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  • richardmitnick 3:34 pm on May 22, 2016 Permalink | Reply
    Tags: , , , , , Particle Accelerators,   

    From HuffPost: “Meet The Most Powerful Woman In Particle Physics” Women in Science 

    Huffington Post
    The Huffington Post

    05/18/2016
    David Freeman

    1
    Fabiola Gianotti, CERN’s new director-general. Christian Beutler

    Fabiola Gianotti isn’t new to CERN, the Geneva, Switzerland-based research organization that operates the Large Hadron Collider (LHC), the world’s biggest particle collider.

    CERN/LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    In fact, the Italian particle physicist was among the CERN scientists who made history in 2012 with the discovery of the Higgs boson.

    CERN CMS Higgs Event
    CERN CMS Higgs Event

    CERN/CMS Detector
    CERN/CMS Detector

    But now Gianotti isn’t just working at CERN. As the organization’s new director-general — the first woman ever to hold the position — she’s running the show. And though expanding our knowledge of the subatomic realm remains her main focus, she’s acutely aware that she is now a high-visibility role model for women around the world.

    “Physics is widely regarding as a male-dominated field, and it’s true that there are more men in our community than women,” Gianotti told The Huffington Post in an email. “So I am glad if in my new role I can contribute to encourage young women to undertake a job in scientific research with the certitude that they have the same opportunities as men.”

    Recently, HuffPost Science posed a few questions to Gianotti via email. Here, lightly edited, are her answers.

    How will things be different for you in your new role?

    My new role is very interesting and stimulating, and I feel very honored to have been offered it. The range of issues I have to deal with is much broader than before and includes scientific strategy and planning, budget, personnel aspects, relations with a large variety of stakeholders, etc. Days are long and full, and I am learning many new things. And there is nothing more enriching and gratifying than learning.

    What’s a typical day like for you?

    Super-hectic, super-speedy and … atypical!

    What do you think explains the gender gap in science generally and in physics particularly?

    There are many factors. There’s no difference in ability between men and women, that’s for sure. And in my experience, the more diverse a team is, the stronger it is. There is the baggage of history, of course, which takes a long time to overcome. There is the question of the lack of role models, and there is the question of making workplaces more family friendly. We need to enable parents, men or women, to take breaks to raise families and we need to support parents with infrastructure and facilities.

    2
    The Large Hadron Collider, Geneva, Switzerland.

    Your term as CERN’s director-general is scheduled to last five years. What are your goals for CERN during this period?

    The second run of the LHC is the top priority for CERN in the coming years. We got off to a very good start in 2015, and have three years of data-taking ahead of us before we go into the accelerator’s second long shutdown. The experiments are expected to record at least three times more data than in Run 1 at an energy almost twice as large. It will be a long time before another such step in energy will be made in the future.

    So, the coming years are going to be an exciting period for high-energy physics. But CERN is not just the LHC. We have a variety of experiments and facilities, including precise measurements of rare decays and detailed studies of antimatter, to mention just a couple of them. In parallel with the ongoing program, we will be working to ensure a healthy long-term future for CERN, at first with the high-luminosity LHC upgrade scheduled to come on stream in the middle of the next decade, and also through a range of design studies looking at the post-LHC era — from 2035 onwards.

    CERN HL-LHC bloc

    What discoveries can we reasonably expect from CERN during your term?

    I’m afraid that I don’t have a crystal ball to hand. There will be a wealth of excellent physics results from the LHC Run 2 and from other CERN experiments. We’ll certainly get to know the Higgs boson much better and expand our exploration of physics beyond the Standard Model.

    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.
    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    Whether we find any hints of the new physics everyone is so eagerly waiting for, however, I don’t know. We know there’s new physics to be found. Good as it is, the Standard Model explains only the 5 percent of the universe that is visible. There are so many exciting questions still waiting to be answered.

    What are the biggest opportunities at CERN? The biggest challenges?

    These two questions have a single answer. Over the coming years, the greatest opportunities and challenges, not only for CERN but for the global particle physics community as a whole, come from the changing nature of the field. Collaboration between regions is growing. CERN recently signed a set of agreements with the U.S. outlining U.S. participation in the upgrade of the LHC and CERN participation in neutrino projects at Fermilab in the U.S.

    FNAL LBNF/DUNE
    FNAL LBNF/DUNE

    There are also emerging players in the field, notably China, whose scientific community has expressed ambitious goals for a potential future facility. All this represents a great opportunity for particle physics. The challenge for all of us in the field is to advance in a globally coordinated manner, so as to be able to carry out as many exciting and complementary projects as possible.

    Were you always interested in being a scientist? If you couldn’t be a scientist, what would you be/do?

    I was always interested in science, and I was always interested in music. I pursued both for as long as I could, but when the time came to make a choice, I chose science. I suppose that as a professional physicist, it is still possible to enjoy music — I still play the piano from time to time. But as a professional musician, it would be harder to engage in science.

    What do you do in your spare time?

    I spend my little spare time with family and friends. I do some sport, I listen to music, I read.

    What do you think is the biggest misconception nonscientists have about particle physics?

    That it’s hard to understand! Of course, if you want to be a particle physicist, you have to master the language of mathematics and be trained to quite a high level. But if you want to understand the field conceptually, it’s almost child’s play. All children are natural scientists. They are curious, and they want to take things apart to see how they work.

    Particle physics is just like that. We study the fundamental building blocks of matter from which everything is made, and the forces at work between them. And the equations that describe the building blocks and their interactions are simple and elegant. They can be written on a small piece of paper.

    See the full article here .

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  • richardmitnick 8:28 am on May 22, 2016 Permalink | Reply
    Tags: , , , , , Particle Accelerators,   

    From livescience: “LHC [Particle] Smasher Opens Quantum Physics Floodgates” 

    Livescience

    May 20, 2016
    Ian O’Neill, Discovery News

    1
    A display of a proton-proton collision taken in the LHCb detector in the early hours of May 9.
    Credit: CERN/LHCB

    CERN/LHCb
    CERN/LHCb

    A display of a proton-proton collision taken in the LHCb detector in the early hours of May 9. Credit: CERN/LHCb

    The Large Hadron Collider is the most complex machine ever built by humankind and it is probing into deep quantum unknown, revealing never-before-seen detail in the matter and forces that underpin the foundations of our universe.

    CERN/LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    In its most basic sense, the LHC is a time machine; with each relativistic proton-on-proton collision, the particle accelerator is revealing energy densities and states of matter that haven’t existed in our universe since the moment after the Big Bang, nearly 14 billion years ago.

    The collider, which is managed by the European Organization for Nuclear Research (CERN) is located near Geneva, Switzerland.

    With the countless billions of collisions between ions inside the LHC’s detectors comes a firehose of data that needs to be recorded, deciphered and stored. Since the 27 kilometer (17 mile) circumference ring of supercooled electromagnets started smashing protons together once more after its winter break, LHC scientists are expecting a lot more data this year than what the experiment produced in 2015.

    “The LHC is running extremely well,” said CERN Director for Accelerators and Technology Frédérick Bordry in a statement. “We now have an ambitious goal for 2016, as we plan to deliver around six times more data than in 2015.”

    And this data will contain ever more detailed information about the elusive Higgs boson that was discovered in 2012 and possibly even details of “new” or “exotic” physics that physicists could spend decades trying to understand. Key to the LHC’s aims is to attempt to understand what dark matter is and why the universe is composed of matter and not antimatter.

    In fact, there was already a buzz surrounding an unexpected signal that was recorded in 2015 that could represent something amazing, but as is the mantra of any scientist: more data is needed. And it looks like LHC physicists are about to be flooded with the stuff.

    Central to the LHC’s recent upgrades is the sheer density of accelerated “beams” of protons that are accelerated to close to the speed of light. The more concentrated or focused the beams, the more collisions can be achieved. More collisions means more data and the more likelihood of revealing new and exciting things about our universe. This year, LHC engineers hope to magnetically squeeze the beams of protons when they collide inside the detectors, generating up to one billion proton collisions per second.

    Add these advances in extreme beam control with the fact the LHC will be running at a record-breaking collision energy of 13 TeV and we have the unprecedented opportunity to make some groundbreaking discoveries.

    “In 2015, we opened the doors to a completely new landscape with unprecedented energy. Now we can begin to explore this landscape in depth,” said CERN Director for Research and Computing, Eckhard Elsen.

    The current plan is to continue proton-proton collisions for six months and then carry out a four-week run using much heavier lead ions.

    So the message is clear: Hold onto your hats. We’re in for an incredible year of discovery that could confirm or deny certain models of our universe and revel something completely unexpected and, possibly, something very exotic.

    See the full article here .

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  • richardmitnick 9:07 am on May 14, 2016 Permalink | Reply
    Tags: , Boston U, Boston U Bump Hunters, , , Particle Accelerators, ,   

    From BU: “Bump Hunters” 

    Boston University Bloc

    Boston University

    5.14.16
    Elizabeth Dougherty

    Boston U Bump Hunters Steve Ahlen, Kenneth Lane, Tulika Bose, Kevin Black, Sheldon Glashow
    Bump Hunters Steve Ahlen, Kenneth Lane, Tulika Bose, Kevin Black, Sheldon Glashow

    Tulika Bose stands guard over the printer.

    She’s carried her laptop down the hall and submitted her print job on arrival to be certain that she will intercept her papers before anyone else has a chance to see them. Her documents contain secrets.

    Bose is a physicist working at the Large Hadron Collider (LHC) in Switzerland.

    CERN/LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    Her work has nothing to do with weapons or national defense or space exploration or any of the usual top-secret stuff physicists work on. What her files contain are ideas about what we—everything under the sun and beyond it—are made of. Her documents could contain the secrets of the universe.


    Access mp4 video here .
    When Protons Collide: A proton collision is like a car accident—except when it isn’t. Physicist Kevin Black explains why. (Watch out for the kitchen sink!) Video by Joe Chan

    An associate professor of physics at Boston University, Bose is part of a cadre of physicists at BU committed to understanding matter down to its smallest particles and most intricate interactions. BU is unusual, one of only a small handful of US universities with researchers working on multiple experiments at the LHC.

    These experiments are looking for signs of particles that have never been seen before. The particles familiar from high school physics—electrons, protons, and neutrons—were just the beginning. Over the past several decades, physicists have confirmed that there are six kinds of quarks; three types of leptons; and assorted bosons, including photons, gluons, and the famed Higgs. These particles only exist in high-energy environments, such as the LHC, where protons are sent hurtling around a ring at speeds very close to the speed of light, colliding together spectacularly. All of the particles that are predicted to exist by the accepted theory of particle physics, called the Standard Model, have been found through experiments like those done at the LHC.

    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.
    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    2
    A theoretical physicist since the 1960s and a Nobel Laureate, Glashow came to BU in 2000 because of the physics department’s emphasis on experiments like those at the LHC. Photo by Gina Manning

    U also happens to have on its faculty Sheldon Glashow, a BU College of Arts & Sciences physics professor, who won the Nobel Prize in Physics in 1979 for his work developing the foundations of the Standard Model. Theorists like Glashow and Kenneth Lane, also a BU professor of physics, and experimental physicists like Bose have become masters of the Standard Model and are spending their careers trying to figure out one thing: Is there more to the universe than what we know right now?

    The answer, almost surely, is yes.

    When physicists look for new particles, they are really looking for “bumps” in the data produced by their experiments. A bump indicates that something appeared with energy or mass that was different than expected. “We call it ‘bump hunting,’” says Steve Ahlen, BU professor of physics, who represents yet another flavor of physicist. A hardware physicist, Ahlen has built muon detector chambers with his own hands and led their construction in Boston. Those built in Boston were auspiciously placed at the LHC and captured a good portion of the particles that allowed researchers to confirm the existence of the Higgs boson in 2012.

    The hunt is on, at a time like no other in physics. The quest reached a pinnacle with the Higgs boson, but finding it wasn’t the end. It was just the beginning.

    “Before the Higgs was discovered, people were absolutely convinced that it was there. The challenge was finding it,” says Glashow. “The trouble now is that we theorists don’t know what else is out there. We are no longer so confident that we know what to look for. But we hope that something interesting will show up.”

    On Colliders and Detectors

    The Large Hadron Collider is currently the world’s highest energy particle collider. It is also the largest machine ever built. The circular tunnel around which proton beams fly is 17 miles wide and buried 574 feet underground in a rural area on the border of France and Switzerland at the European Organization for Nuclear Research (CERN). The collider’s job is to smash particles together at high speeds and record the spray of shrapnel that results, so that physicists can look for signs of new particles. If they find something that looks interesting, they piece the data back together again, retracing the paths of all the particles in the spray back to the collision that caused them.

    “I think of it as if a murder has happened, and you have all these clues,” says Bose. “The detective comes in and uses all these clues to reconstruct the scene and figure out who committed the crime.”

    In 2015, the LHC operated at 13 tera-electron-volts (TeV), the highest energy level yet. One TeV is a trillion electron-volts, which sounds like a lot. It is, but it is small compared to the energy consumed by light bulbs and laptops and other things of daily life. A tera-electron-volt is approximately equal to the energy of a single flying mosquito. What the LHC does, beyond multiplying that energy by 13, is compress it into the space of a proton beam, a million million times smaller than a mosquito.

    At this energy level, the LHC can accelerate protons to speeds extremely close to the speed of light. Further, it bundles those protons, with each beam containing a thousand bunches of about a hundred billion protons per bunch. Packing far more punch than a mosquito, the total energy of a beam is more like a 17-ton plane flying over 460 miles per hour.

    In March 2016, the collider began running again, this time with more intense beams. This increased brightness will make for more collisions per second, so the LHC will produce approximately six times more data than in 2015. “We’re just beginning to tap its potential,” says Kevin Black, an associate professor of physics at BU, and also Bose’s husband. Bose and her students work on an experiment called CMS at LHC. Black works on a different experiment there called ATLAS.

    The CMS and ATLAS experiments are, at their core, two different pieces of hardware that detect particles.

    CERN/CMS Detector
    CERN CMS Higgs Event
    CERN/CMS and Higgs event at CMS

    CERN/ATLAS
    CERN ATLAS Higgs Event
    CERN/ATLAS andHiggs event at ATLAS

    They sit at opposite sides of the beam ring surrounding two separate beam intersections, where they capture all of the shrapnel from the proton-proton collisions that occur at their centers.

    The ATLAS detector, which Ahlen helped build, is a 75-foot-high, 140-foot-long machine in which five layers of detection hardware measure the momentum and mass of particles produced when protons smash together. CMS, for Compact Muon Solenoid, is considerably smaller and more dense. It captures the same types of particles as ATLAS, just in a different way.

    2
    A hands-on physicist, Ahlen likes to build things. He is currently building dark energy detectors and climbing mountains to install them on telescopes. Photo by Gina Manning

    These machines can detect all of the particles defined in the Standard Model. Take muons as an example. A muon is a tiny particle, even by the standards of particle physicists, that is produced inside colliders and also when cosmic rays strike the atmosphere. When Ahlen got involved with the development of detectors for particle colliders in the 1990s, it wasn’t clear how to detect muons affordably. He came up with a simple solution: A twelve-foot-long, two-inch-diameter aluminum tube, crimped at both ends and filled with gas, with a wire stretched under tension from end to end. “If you pressurize it, it can localize the trajectory of a particle that passes through the tube,” he says, waving around a spare tube he keeps behind the door in his office.

    The ATLAS detector, which has several layers of specialized particle detectors, contains about 500,000 of these tubes. They were built all over the world to exacting standards, many in Boston by Ahlen, who borrowed and bartered equipment and materials to get the job done.

    While the tubes themselves might not seem so special, keep in mind that each tube in the ATLAS detector must be precisely placed. “We know where each wire is to less than the width of a human hair,” says Ahlen.

    Not only that, every particle that whizzes by must be recorded, along with the exact time it flew through. So every tube and every other sensor in the detector—tens of millions of them in total—is connected to a clock. The clocks are set to the beam crossing, which occurs every 25 nanoseconds. The first crossing is one. “The second, two, the third, three,” says Ahlen. “Every 25 nanoseconds, boom, boom.”

    There were 40 million beam crossings per second, and about a billion proton-proton collisions per second, in the last run of the LHC.

    The time-stamped data flows from each detector down an electrical pipe to join with others in a raging river of data. Carefully coded computer algorithms determine which events to keep and which to throw away. Bose, who is the “trigger” in charge of this gatekeeping for CMS, saves only about a thousand events per second. A lot, but still just a tiny fraction of the data produced.

    Secret Keepers

    CMS and ATLAS produce and save independent sets of data and have independent teams analyzing it. Bose, for example, is one of nearly 4,000 people working on the CMS experiment, while Black is part of a team of 3,000 people working on ATLAS.

    The teams sift through their data in secret, without sharing early results. At a time when data sharing in science is all the rage, secrecy seems to go against the grain, but it is a necessity in physics. In the past, there have been cases where rumors about the early sightings of new particles lead to false discoveries. In one case, physicists started looking for signs of a new particle people were buzzing about. “Any run that had a little bump in the rumored location, they kept,” says Black. “Anything that didn’t, they found a reason to throw out the data. Inadvertently, they self-selected the particle into existence.” In the end, an unbiased look at the data proved that the particle did not exist.

    3
    For Black (PhD ’05), who is currently stationed at the LHC in Switzerland, patience is a virtue. The phenomena he studies occur so rarely that even with millions of collisions per second, he might not see them. Photo by Darrin Vanselow

    So experimentalists like Bose and Black try not to share data. In fact, they try extra hard, since the two are married. “We don’t talk about the details,” says Black. “I think we actually have more of a dividing line there because we are worried that if there is any leak, people might look to us first.”

    In practice, though, that line is a bit murky. The thousands of scientists at the LHC work side-by-side. The offices of scientists on different experiments are intermeshed. They share cafeterias and printers and hold open-door seminars to discuss ideas. Despite all this openness, no one wants to undermine the credibility of the science they are doing. “From a pure science point of view, the result is much stronger when two independent experiments come up with the same answer without biasing each other,” says Bose. “We try to keep an open mind. You look everywhere and you see what you see.”

    In the end, it isn’t just secrecy that keeps the science pure. Particle physicists have also set a very high bar for discovery. For a new particle to be accepted, scientists must be confident that it is not a statistical fluctuation. They’ve agreed on a number, 5-sigma, which means that the chance of the data being a statistical fluctuation is 1 in 3.5 million.

    The concept of sigma might be familiar from basic statistics—or from tests graded on a curve. One standard deviation from the mean on a bell curve is called one-sigma. Students scoring two- or three-sigma above (or below) are rare and end up with the grades to prove it.

    But the LHC doesn’t make its findings based on a single test. A bump at the LHC stands out against the bell curves of all the tests ever run. This mass of data all taken together, says Bose, is called “background.” It forms a landscape that has become familiar to physicists. A bump like the Higgs appears as a blot on this predictable landscape, a little like the unexpected genius who shows up for test after test and busts the curve.

    The bump that physicists recognized as the first sign of the Higgs boson was produced by data from about 10 collisions. Even with such scant data, the confidence level was about 4-sigma because the Higgs stood out so starkly against the familiar background. Later, when all of the data came together, about 40 events produced a more pronounced bump with a confidence level of 8-sigma. “That’s a very clean discovery,” says Ahlen.

    From Old Physics, New

    The LHC fired up its proton beams again in March 2016, and saw its first collisions on April 23. The hope is that at the planned higher energy level, it will produce more dramatic collisions that will allow physicists to discover something new.

    “The best thing that could happen is that we’ll discover a whole set of new particles that don’t make any sense at all,” says Black. “I’m hopeful that sort of thing will happen, that we’ll discover something that truly doesn’t make sense and we’ll really learn something from it.”

    Physicists refer to their quest as a search for “new physics,” begging the question: What’s wrong with the old physics? It’s not so much that the old physics doesn’t work—it does, amazingly well—but ask any particle physicist, and they will tell you there’s something about it that just isn’t satisfying. Parameters have to line up in very specific ways for some calculations to work out. If something is off by a smidgen, everything falls apart.

    “This kind of special balancing out of parameters in the current theory gives us the impression that there has to be some underlying principle that we’re missing,” says Black.

    So it is and so it has always been in physics. It all started back when the Greeks came up with the solid but incomplete idea of the atom. Centuries later, Newton’s experiments resulted in Newtonian mechanics, which brilliantly explain the day-to-day physics of the movements of planets in space and objects on Earth. Things got heady in the late 1800s when scientists started to understand electrical currents and magnetic fields. The early 20th century gave rise to quantum theory, which explains the world of tiny, energetic things, like photons. According to Lane, every successful theory has engulfed its predecessor. “Quantum mechanics ate the physics of the 18th and 19th centuries alive,” he says.

    The most recent meal, so to speak, was devoured in the 1960s and 70s by the Standard Model. By 1960, physicists knew about weak nuclear forces, which govern how particles decay into other particles. But no one knew how this force was related to existing theories of electromagnetism. Glashow worked out a new model for weak nuclear forces that relied on three new particles.

    “No one cared,” he says, until 1967, when Glashow’s idea morphed, in a confluence of other ideas, into a theory that made sense: The Standard Model. “Experimenters went out of their way to verify the predictions of the theory,” says Glashow, who won the Nobel Prize alongside Steven Weinberg and Abdus Salam for their work. “Lo and behold, the theory was right.”

    For theorists like Glashow and Lane, the observations of experiments lend credence to theory, and theory provides a rationale for understanding and deciphering what is seen in experiments. “Physics is an experimental science,” says Lane. “It’s not mathematics or philosophy. If it can’t be tested by experiment, it ain’t physics.”

    The most recent piece of experimental data confirming the Standard Model was the discovery of the Higgs boson in 2012. For Lane, the Higgs was a bit of a disappointment. “It’s kind of a simple-minded solution to a big problem,” he says. “Some people still feel burned by this discovery. Me, for example.”

    But ultimately, Lane is interested in figuring out what the most basic, fundamental particles are and how they interact with one another. “Right now, we have a story for that, but there’s always been a story for that,” he says.

    As long as people have been curious about the world they live in, they’ve been coming up with theories, testing them, and making them better. “This,” says Lane, “is an enterprise that need have no end.”

    See the full article here .

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    Boston University is no small operation. With over 33,000 undergraduate and graduate students from more than 130 countries, nearly 10,000 faculty and staff, 17 schools and colleges, and 250 fields of study, our two campuses are always humming, always in high gear.

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  • richardmitnick 1:52 pm on May 13, 2016 Permalink | Reply
    Tags: , , , , Particle Accelerators, ,   

    From FNAL: “What do theorists do?” 

    FNAL II photo

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    May 13, 2016
    Leah Hesla
    Rashmi Shivni

    1
    Pilar Coloma (left) and Seyda Ipek write calculations from floor to ceiling as they try to find solutions to lingering questions about our current models of the universe. Photo: Rashmi Shivni, OC

    Some of the ideas you’ve probably had about theoretical physicists are true.

    They toil away at complicated equations. The amount of time they spend on their computers rivals that of millennials on their hand-held devices. And almost nothing of what they turn up will ever be understood by most of us.

    The statements are true, but as you might expect, the resulting portrait of ivory tower isolation misses the mark.

    The theorist’s task is to explain why we see what we see and predict what we might expect to see, and such pronouncements can’t be made from the proverbial armchair. Theorists work with experimentalists, their counterparts in the proverbial field, as a vital part of the feedback loop of scientific investigation.

    “Sometimes I bounce ideas off experimentalists and learn from what they have seen in their results,” said Fermilab theorist Pilar Coloma, who studies neutrino physics. “Or they may find something profound in theory models that they want to test. My job is all about pushing the knowledge forward so other people can use it.”

    Predictive power

    Theorists in particle physics — the Higgses and Hawkings of the world — push knowledge by making predictions about particle interactions. Starting from the framework known as the Standard Model, they calculate, say, the likelihood of numerous outcomes from the interaction of two electrons, like a blackjack player scanning through the possibilities for the dealer’s next draw.

    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.
    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    Experimentalists can then seek out the predicted phenomena, rooting around in the data for a never-before-seen phenomenon.

    Theorists’ predictions keep experimentalists from having to shoot in the dark. Like an experienced paleontologist, the theorist can tell the experimentalist where to dig to find something new.

    “We simulate many fake events,” Coloma said. “The simulated data determines the prospects for an experiment or puts a bound on a new physics model.”

    The Higgs boson provides one example.

    CERN ATLAS Higgs Event
    CERN ATLAS Higgs Event

    By 2011, a year before CERN’s ATLAS and CMS experiments announced they’d discovered the Higgs boson, theorists had put forth nearly 100 different proposals by as many different methods for the particle’s mass. Many of the predictions were indeed in the neighborhood of the mass as measured by the two experiments.

    CERN/LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    CERN/ATLAS
    CERN/ATLAS

    CERN/CMS Detector
    CERN/CMS Detector

    And like the paleontologist presented with a new artifact, the theorist also offers explanations for unexplained sightings in experimentalists’ data. She might compare the particle signatures in the detector against her many fake events. Or given an intriguing measurement, she might fold it into the next iteration of calculations. If experimentalists see a particle made of a quark combination not yet on the books, theorists would respond by explaining the underlying mechanism or, if there isn’t one yet, work it out.

    “Experimentalists give you information. ‘We think this particle is of this type. Do you know of any Standard Model particle that fits?’” said Seyda Ipek, a theorist studying the matter-antimatter imbalance in the universe. “At first it might not be obvious, because when you add something new, you change the other observations you know are in the Standard Model, and that puts a constraint on your models.”

    And since the grand aim of particle physics theory is to be able to explain all of nature, the calculation developed to explain a new phenomenon must be extendible to a general principle.

    “Unless you have a very good prediction from theory, you can’t convert that experimental measurement into a parameter that appears in the underlying theory of the Standard Model,” said Fermilab theorist John Campbell, who works on precision theoretical predictions for the ATLAS and CMS experiments at the Large Hadron Collider.

    Calculating moves

    The theorist’s calculation starts with the prospect of a new measurement or a hole in a theory.

    “You look at the interesting things that an experiment is going to measure or that you have a chance of measuring,” Campbell said. “If the data agrees with theory everywhere, there’s not much room for new physics. So you look for small deviations that might be a sign of something. You’re really trying to dream up a new set of interactions that might explain why the data doesn’t agree somewhere.”

    In its raw form, particle physics data is the amount and location of the energy a particle deposits in a particle detector. The more sensitive the detector, the more accurate the experimentalists’ measurement, and the more precise the corresponding calculation needs to be.

    2
    Fermilab theorists John Campbell (left) and Ye Li work on a calculation that describes the interactions you might expect to see in the complicated environment of the LHC. Photo: Rashmi Shivni

    The CMS detector at the Large Hadron Collider, for example, allows scientists to measure some probabilities of particle interactions to within a few percent. And that’s after taking into account that it takes one million or even one billion proton-proton collisions to produce just one interesting interaction that CMS would like to measure.

    “When you’re making the measurement that accurately, it demands a prediction at a very high level,” Campbell said. “If you’re looking for something unexpected, then you need to know the expected part in quite a lot of detail.”

    A paleontologist recognizes the vertebra of a brachiosaurus, and the theoretical particle physicist knows what the production of a pair of top quarks looks like in the detector. A departure from the known picture triggers him to take action.

    “So then you embark on this calculation,” Campbell said.

    Embark, indeed. These calculations are not pencil-and-paper assignments. A single calculation predicting the details of a particle interaction, for example, can be a prodigious effort that takes months or years.

    So-called loop corrections are one example: Theorists home in on what happens during a particle event by adding detail — a correction — to an approximate picture.

    Consider two electrons that approach each other, exchange a photon and diverge. Zooming in further, you predict that the photon emits and reabsorbs yet another pair of particles before it itself is reabsorbed by the electron pair. And perhaps you predict that, at the same time, one of the electrons emits and reabsorbs another photon all on its own.

    Each additional quantum-scale effect, or loop, in the big-picture interaction is like pennies on the dollar, changing the accounting of the total transaction — the precision of a particle mass calculation or of the interaction strength between two particles.

    With each additional loop, the task of performing the calculation becomes that much more formidable. (“Loop” reflects how the effects are represented pictorially in Feynman diagrams — details in the approximate picture of the interaction.) Theorists were computing one-loop corrections for the production of a Higgs boson arising from two protons until 1991. It took another 10 years to complete the two-loop corrections for the process. And it wasn’t until this year, 2016, that they finished computing the three-loop corrections. Precise measurements at the Large Hadron Collider would (and do) require precise predictions to determine the kind of Higgs boson that scientists would see, demanding the decades-long investment.

    “Doing these calculations is not straightforward, or we would have done them a long time ago,” Campbell said.

    Once the theorist completes a calculation, they might publish a paper or otherwise make their code broadly available. From there, experimentalists can use the code to simulate how it will look in the detector. Farms of computers map out millions of fake events that take into account the new predictions provided courtesy of the theorist.

    “Without a network of computers available, our studies can’t be done in a reasonable time,” Coloma said. “A single computer can not analyze millions of data points, just as a human being could never take on such a task.”

    If the simulation shows that, for example, a particle might decay in more ways than what the experiment has seen, the theorist could suggest that experimentalists expand their search.

    “We’ve pushed experiments to look in different channels,” Ipek said. “They could look into decays of particles into two-body states, but why not also 10-body states?”

    Theorists also work with an experiment, or multiple experiments, to put their calculations to best use. Armed with code, experimentalists can change a parameter or two to guide them in their search for new physics. What happens, for example, if the Higgs boson interacts a little more strongly with the top quark than we expect? How would that change what we see in our detectors?

    “That’s a question they can ask and then answer,” Campbell said. “Anyone can come up with a new theory. It is best to try to provide a concrete plan that they can follow.”

    Outlandish theories and concrete plans

    Concrete plans ensure a fruitful relationship between experiment and theory. The wilder, unconventional theories scientists dream up take the field into exciting, uncharted territory, but that isn’t to say that they don’t also have their utility.

    Theorists who specialize in physics beyond the Standard Model, for example, generate thousands of theories worldwide for new physics – new phenomena seen as new energy deposits in the detector where you don’t expect to see them.

    “Even if things don’t end up existing, it encourages the experiment to look at its data in different ways,” Campbell said. An experiment could take so much data that you might worry that some fun effect is hiding, never to be seen. Having truckloads of theories helps mitigate against that. “You’re trying to come up with as many outlandish ideas as you can in the hope that you cover as many of those possibilities as you can.”

    Theorists bridge the gap between the pure mathematics that describes nature and the data through which nature manifests.

    “The field itself is challenging, but theory takes us to new places and helps us imagine new phenomena,” Ipek said.” We collectively work toward understanding every detail of our universe and that’s what ultimately matters most.”

    See the full article here .

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 6:49 am on May 10, 2016 Permalink | Reply
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    From Cern Atlas: “ATLAS continues to explore the 13 TeV frontier” 

    CERN ATLAS Higgs Event

    CERN/ATLAS
    ATLAS

    9th May 2016

    ATLAS is back and better than ever! With 13 TeV beams circulating in the Large Hadron Collider, the ATLAS experiment is now recording data for physics. This milestone marks the start of the second year of “Run 2” as ATLAS continues its exploration of 13 TeV energy frontier.

    Anticipation is high for 2016, with the year set to deliver exciting new results for physicists around the world. From precision studies of the Higgs boson to searches for new particles, this year’s data will deepen our understanding of Nature. “We welcome the first 13 TeV collisions of the year with the careful preparation and great expectations of a good friend’s anticipated encounter,” says Alessandro Cerri, ATLAS Run Co-Coordinator. “Together, we are ready for new, exciting explorations!”

    1
    One of the early collision events with stable beams recorded by ATLAS in 2016. (Image: ATLAS Experiment/CERN)

    Today’s smooth start was thanks to the hard work and dedication of countless ATLAS teams. ATLAS physicists were able to hit the ground running, harnessing last year’s experience running at 13 TeV. “The ATLAS teams have done an incredible job to further improve the performance of the detector and get the systems up and running again in step with the swift start-up of LHC in 2016,” says Alex Oh, ATLAS Run Co-Coordinator. “It’s going to be an exiting year for ATLAS and the other LHC experiments with hopefully great discoveries to be made.”

    “The mission of the data preparation team is to get the best quality data to the physics analysis teams as quickly as possible. We’ve learned from our experience in 2015 and this year we will be faster, with even better data quality,” adds Paul Laycock, ATLAS Data Preparation Coordinator.

    Over the next 6 months of operation with proton beams, the ATLAS experiment will see up to a billion collisions per second. Selecting the most interesting of these collisions is the ATLAS trigger: “It is with great excitement and satisfaction we see the ATLAS trigger system smoothly selecting events for analysis; the many months of preparation and the long nights our experts spent at the control room certainly paid off!” says Anna Sfyrla, ATLAS Trigger Coordinator. “We now need to be patient for more LHC data to come and look into them for the next surprises Nature holds for us.”

    “2015 was like watching the film trailer, there were tantalising glimpses of something amazing happening,” concludes Paul Laycock. “In 2016 we’re looking forward to watching the whole film!”

    See the full article here .

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

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  • richardmitnick 12:21 pm on May 9, 2016 Permalink | Reply
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    From FNAL: “Large Hadron Collider prepares to deliver six times the data” 

    FNAL II photo

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    May 9, 2016

    Media contact

    Andre Salles, Fermilab Office of Communication, asalles@fnal.gov, 630-840-6733
    Ivy F. Kupec, National Science Foundation, ikupec@nsf.gov, 703-292-8796
    Rick Borchelt, U.S. Department of Energy Office of Communications and Public Affairs, rick.borchelt@science.doe.gov, 202-586-4477
    Sarah Charley, US LHC, scharley@fnal.gov, 630-338-3034 (cell)

    1
    Collisions recorded on May 7, 2016, by the CMS detector on the Large Hadron Collider. After a winter break, the LHC is now taking data again at extraordinary energies. Image: CERN

    Experiments at the LHC are once again recording collisions at extraordinary energies

    Editor’s note: The following news release about the restart of the Large Hadron Collider is being issued by the U.S. Department of Energy’s Fermi National Accelerator Laboratory on behalf of the U.S. scientists working on the LHC. Fermilab serves as the U.S. hub for the CMS experiment at the LHC and the roughly 1,000 U.S. scientists who work on that experiment, including about 100 Fermilab employees. Fermilab is a Tier 1 computing center for LHC data and hosts a Remote Operations Center to process and analyze that data. Read more information about Fermilab’s role in the CMS experiment and the LHC. Fermilab scientists are available for interviews upon request, including Joel Butler, recently elected next spokesperson of the CMS experiment.

    CERN/LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    After months of winter hibernation, the Large Hadron Collider is once again smashing protons and taking data. The LHC will run around the clock for the next six months and produce roughly 2 quadrillion high-quality proton collisions, six times more than in 2015 and just shy of the total number of collisions recorded during the nearly three years of the collider’s first run.

    “2015 was a recommissioning year. 2016 will be a year of full data production during which we will focus on delivering the maximum number of data to the experiments,” said Fabiola Gianotti, CERN director general.

    CERN Fabiola Gianotti
    Fabiola Gianotti

    The LHC is the world’s most powerful particle accelerator. Its collisions produce subatomic fireballs of energy, which morph into the fundamental building blocks of matter. The four particle detectors located on the LHC’s ring allow scientists to record and study the properties of these building blocks and look for new fundamental particles and forces.

    “We’re proud to support more than a thousand U.S. scientists and engineers who play integral parts in operating the detectors, analyzing the data and developing tools and technologies to upgrade the LHC’s performance in this international endeavor,” said Jim Siegrist, associate director of science for high-energy physics in the U.S. Department of Energy’s Office of Science. “The LHC is the only place in the world where this kind of research can be performed, and we are a fully committed partner on the LHC experiments and the future development of the collider itself.”

    [Never should it be forgotten that this work could have proceeded i the US had the US Congress followed through with funding for the Superconducting Super Collider which had begun construction in Texas. In 1993, our congress decided to stop this project and leave this research to others.]

    Between 2010 and 2013 the LHC produced proton-proton collisions with 8 teraelectronvolts of energy. In the spring of 2015, after a two-year shutdown, LHC operators ramped up the collision energy to 13 TeV. This increase in energy enables scientists to explore a new realm of physics that was previously inaccessible. Run II collisions also produce Higgs bosons — the groundbreaking particle discovered in LHC Run I — 25 percent faster than Run I collisions and increase the chances of finding new massive particles by more than 40 percent.

    Almost everything we know about matter is summed up in the Standard Model of particle physics, an elegant map of the subatomic world.

    The Standard Model of elementary particles , with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.
    The Standard Model of elementary particles , with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    During the first run of the LHC, scientists on the ATLAS and CMS experiments discovered the Higgs boson, the cornerstone of the Standard Model that helps explain the origins of mass.

    CERN/ATLAS
    CERN ATLAS Higgs Event
    ATLAS

    CERN/CMS Detector
    CERN CMS Higgs Event
    CMS

    The LHCb experiment also discovered never-before-seen five-quark particles, and the ALICE experiment studied the near-perfect liquid that existed immediately after the Big Bang. All these observations are in line with the predictions of the Standard Model.

    CERN/LHCb
    LHCb

    AliceDetectorLarge
    ALICE

    “So far the Standard Model seems to explain matter, but we know there has to be something beyond the Standard Model,” said Denise Caldwell, director of the Physics Division of the National Science Foundation. “This potential new physics can only be uncovered with more data that will come with the next LHC run.”

    For example, the Standard Model contains no explanation of gravity, which is one of the four fundamental forces in the universe. It also does not explain astronomical observations of dark matter, a type of matter that interacts with our visible universe only through gravity, nor does it explain why matter prevailed over antimatter during the formation of the early universe. The small mass of the Higgs boson also suggests that matter is fundamentally unstable.

    The new LHC data will help scientists verify the Standard Model’s predictions and push beyond its boundaries. Many predicted and theoretical subatomic processes are so rare that scientists need billions of collisions to find just a small handful of events that are clean and scientifically interesting. Scientists also need an enormous amount of data to precisely measure well-known Standard Model processes. Any significant deviations from the Standard Model’s predictions could be the first step towards new physics.

    The United States is the largest national contributor to both the ATLAS and CMS experiments, with 45 U.S. universities and laboratories working on ATLAS and 49 working on CMS.

    CERN, the European Organization for Nuclear Research, is the world’s leading laboratory for particle physics. It has its headquarters in Geneva. At present, its member states are Austria, Belgium, Bulgaria, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Israel, Italy, the Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom. Romania is a candidate for accession. Cyprus and Serbia are associate members in the pre-stage to membership. Turkey and Pakistan are associate members. India, Japan, the Russian Federation, the United States of America, Turkey, the European Union, JINR and UNESCO have observer status.

    See the full from FNAL article here .
    See the Symmetry article here .

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 10:43 am on May 2, 2016 Permalink | Reply
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    From phys.org: “Physicists abuzz about possible new particle as CERN revs up” 

    physdotorg
    phys.org

    May 2, 2016
    Jamey Keaten And Frank Jordans

    CERN/LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    Scientists around the globe are revved up with excitement as the world’s biggest atom smasher—best known for revealing the Higgs boson four years ago—starts whirring again to churn out data that may confirm cautious hints of an entirely new particle.

    Higgs Boson Event
    Higgs Boson Event

    Such a discovery would all but upend the most basic understanding of physics, experts say.

    The European Center for Nuclear Research, or CERN by its French-language acronym, has in recent months given more oomph to the machinery in a 27-kilometer (17-mile) underground circuit along the French-Swiss border known as the Large Hadron Collider.

    In a surprise development in December, two separate LHC detectors each turned up faint signs that could indicate a new particle, and since then theorizing has been rife.

    “It’s a hint at a possible discovery,” said theoretical physicist Csaba Csaki, who isn’t involved in the experiments. “If this is really true, then it would possibly be the most exciting thing that I have seen in particle physics in my career—more exciting than the discovery of the Higgs itself.”

    After a wintertime break, the Large Hadron Collider, or LHC, reopened on March 25 to prepare for a restart in early May. CERN scientists are doing safety tests and scrubbing clean the pipes before slamming together large bundles of particles in hopes of producing enough data to clear up that mystery. Firm answers aren’t expected for weeks, if not until an August conference of physicists in Chicago known as ICHEP.

    On Friday, the LHC was temporarily immobilized by a weasel, which invaded a transformer that helps power the machine and set off an electrical outage. CERN says it was one of a few small glitches that will delay by a few days plans to start the data collection at the $4.4 billion collider.

    The 2012 confirmation of the Higgs boson, dubbed the “God particle” by some laypeople, culminated a theory first floated decades earlier. The “Higgs” rounded out the Standard Model of physics, which aims to explain how the universe is structured at the infinitesimal level.

    The LHC’s Atlas and Compact Muon Solenoid particle detectors in December turned up preliminary readings that suggested a particle not accounted for by the Standard Model might exist at 750 Giga electron Volts. This mystery particle would be nearly four times more massive than the top quark, the most massive particle in the model, and six times more massive than the Higgs, CERN officials say.

    CERN/ATLAS
    CERN/ATLAS

    CERN/CMS Detector
    CERN/CMS Detector

    The Standard Model has worked well, but has gaps notably about dark matter, which is believed to make up one-quarter of the mass of the universe.

    The Standard Model of elementary particles , with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.
    The Standard Model of elementary particles , with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    Theorists say the December results, if confirmed, could help elucidate that enigma; or it could signal a graviton—a theorized first particle with gravity—or another boson, even hint of a new dimension.

    More data is needed to iron those possibilities out, and even then, the December results could just be a blip. But with so much still unexplained, physicists say discoveries of new particles—whether this year or later—may be inevitable as colliders get more and more powerful.

    Dave Charlton, who heads the Atlas team, said the December results could just be a “fluctuation” and “in that case, really for science, there’s not really any consequence … At this point, you won’t find any experimentalist who will put any weight on this: We are all very largely expecting it to go away again.”

    “But if it stays around, it’s almost a new ball game,” said Charlton, an experimental physicist at the University of Birmingham in Britain.

    The unprecedented power of the LHC has turned physics on its head in recent years. Whereas theorists once predicted behaviors that experimentalists would test in the lab, the vast energy being pumped into CERN’s collider means scientists are now seeing results for which there isn’t yet a theoretical explanation.

    “This particle—if it’s real—it would be something totally unexpected that tells us we’re missing something interesting,” he said.

    Whatever happens, experimentalists and theorists agree that 2016 promises to be exciting because of the sheer amount of data pumped out from the high-intensity collisions at record-high energy of 13 Tera electron Volts, a level first reached on a smaller scale last year, and up from 8 TeVs previously. (CERN likens 1 TeV to the energy generated by a flying mosquito: That may not sound like much, but it’s being generated at a scale a trillion times smaller.)

    In energy, the LHC will be nearly at full throttle—its maximum is 14 TeV—and over 2,700 bunches of particles will be in beams that collide at the speed of light, which is “nearly the maximum,” CERN spokesman Arnaud Marsollier said. He said the aim is to produce six times more collisions this year than in 2015.

    “When you open up the energies, you open up possibilities to find new particles,” he said. “The window that we’re opening at 13 TeV is very significant. If something exists between 8 and 13 TeV, we’re going to find it.”

    Still, both branches of physics are trying to stay skeptical despite the buzz that’s been growing since December.

    Csaki, a theorist at Cornell University in Ithaca, New York, stressed that the preliminary results don’t qualify as a discovery yet and there’s a good chance they may turn out not to be true. The Higgs boson had been predicted by physicists for a long time before it was finally confirmed, he noted.

    “Right now it’s a statistical game, but the good thing is that there will be a lot of new data coming in this year and hopefully by this summer we will know if this is real or not,” Csaki said, alluding to the Chicago conference. “No vacation in August.”

    See the full article here .

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    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 3:21 pm on April 10, 2016 Permalink | Reply
    Tags: , , , , Particle Accelerators, ,   

    From The Daily Galaxy: “CERN LHC Reveals: “The Universe a Billionth of a Second After the Big Bang” 

    Daily Galaxy
    The Daily Galaxy

    CERN/LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    April 09, 2016
    No writer credit found

    “It is remarkable that we are able to carry out such detailed measurements on a drop of ‘early universe’, that only has a radius of about one millionth of a billionth of a meter. The results are fully consistent with the physical laws of hydrodynamics, i.e. the theory of flowing liquids and it shows that the quark-gluon plasma behaves like a fluid.

    It is however a very special liquid, as it does not consist of molecules like water, but of the fundamental particles quarks and gluons,” explained Jens Jørgen Gaardhøje, professor and head of the ALICE group at the Niels Bohr Institute at the University of Copenhagen.

    A few billionths of a second after the Big Bang, the universe was made up of a kind of extremely hot and dense primordial soup of the most fundamental particles, especially quarks and gluons. This state is called quark-gluon plasma. By colliding lead nuclei at a record-high energy of 5.02 TeV in the world’s most powerful particle accelerator, the 27 km long Large Hadron Collider, LHC at CERN in Geneva, it has been possible to recreate this state in the ALICE experiment’s detector and measure its properties.

    Quark gluon plasma. Duke University
    Quark-gluon plasma. Duke University

    CERN researchers recreated the universe’s primordial soup in miniature format by colliding lead atoms with extremely high energy in the 27 km long particle accelerator, the LHC in Geneva. The primordial soup is a so-called quark-gluon plasma and researchers from the Niels Bohr Institute, among others, have measured its liquid properties with great accuracy at the LHC’s top energy. The results were submitted to Physical Review Letters, which is the top scientific journal for nuclear and particle physics.

    “The analyses of the collisions make it possible, for the first time, to measure the precise characteristics of a quark-gluon plasma at the highest energy ever and to determine how it flows,” explains You Zhou, who is a postdoc in the ALICE research group at the Niels Bohr Institute.

    CERN ALICE Icon HUGE
    ALICE Run Control Center
    CERN ALICE New
    CERN ALICE New II
    CERN ALICE and the Control Room

    You Zhou, together with a small, fast-working team of international collaboration partners, led the analysis of the new data and measured how the quark-gluon plasma flows and fluctuates after it is formed by the collisions between lead ions.

    The focus has been on the quark-gluon plasma’s collective properties, which show that this state of matter behaves more like a liquid than a gas, even at the very highest energy densities. The new measurements, which uses new methods to study the correlation between many particles, make it possible to determine the viscosity of this exotic fluid with great precision.

    You Zhou explains that the experimental method is very advanced and is based on the fact that when two spherical atomic nuclei are shot at each other and hit each other a bit off center, a quark-gluon plasma is formed with a slightly elongated shape somewhat like an American football. This means that the pressure difference between the centre of this extremely hot ‘droplet’ and the surface varies along the different axes. The pressure differential drives the expansion and flow and consequently one can measure a characteristic variation in the number of particles produced in the collisions as a function of the angle.

    Jens Jørgen Gaardhøje adds that they are now in the process of mapping this state with ever increasing precision — and even further back in time.

    See the full article here .

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  • richardmitnick 3:37 pm on April 8, 2016 Permalink | Reply
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    From FNAL: “Heavy neutrinos: Leave no stone unturned” 

    FNAL II photo

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    April 8, 2016
    Bo Jayatilaka

    While the discovery of the Higgs boson at the LHC yielded considerable evidence that the Higgs mechanism is responsible for some particles having mass and others not, it does not help explain why massive particles have the specific masses they do. Over a decade prior to the discovery of the Higgs boson, experiments studying neutrinos produced by the sun and by particle accelerators made the astounding discovery that neutrinos have mass, albeit in incredibly tiny amounts. The question du jour about neutrino masses shifted immediately from “Do neutrinos have mass?” to “Why are neutrino masses what they are?”

    Physicists naturally attack this question from as many angles as possible. A significant focus of the scientific efforts of Fermilab center on studying neutrinos produced by the Fermilab accelerator complex in order to probe this question. An experiment like CMS, designed to measure highly interactive particles, can’t directly detect neutrinos at all and might seem to be left on the sidelines in this quest. However, a popular family of theories suggests that there is an additional family of neutrino linked to the garden-variety neutrinos we know of. This linking mechanism between the known neutrinos and their exotic cousins is known as a “seesaw mechanism,” as it forces one type to become massive when the others become lightweight. Searching for unknown but massive particles is exactly what the CMS detector was designed to do.

    CERN/CMS Detector
    CERN/CMS Detector

    The CMS experiment has searched for such heavy neutrinos, focusing on the case where the heavy neutrino is of the Majorana type, meaning that it is its own antiparticle. As Don Lincoln explains about one of the first such searches, the production and decay of a heavy Majorana neutrino results in the signature of two leptons (electrons or muons) of the same electric charge along with jets. A more recent search at CMS used the full 8-TeV data set and focused on events in which the same-charged leptons were muons.

    To ensure that no stone remains unturned in the search for heavy Majorana neutrinos, the analysis of 8-TeV data has been updated* to include events with like-charged electron pairs and like-charged pairings of an electron and a muon.-

    Unfortunately, as with the previous searches, no evidence of a heavy neutrino was seen. However, the inclusion of electron and electron-muon pair events allowed CMS physicists to place significantly more stringent limits on the possible masses of heavy Majorana neutrinos. With Run 2 of the LHC under way, you can expect searches for Majorana neutrinos to push into ever higher masses.

    *Search for heavy Majorana neutrinos in e+/- e+/- plus jets and e+/- mu+/- plus jets events in proton-proton collisions at sqrt(s) = 8 TeV
    CMS Collaboration

    See the full article here .

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 3:23 pm on April 7, 2016 Permalink | Reply
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    From Symmetry: “Physicists build ultra-powerful accelerator magnet” 

    Symmetry Mag

    Symmetry

    04/07/16
    Sarah Charley

    Magnet built for LHC

    The next generation of cutting-edge accelerator magnets is no longer just an idea. Recent tests revealed that the United States and CERN have successfully co-created a prototype superconducting accelerator magnet that is much more powerful than those currently inside the Large Hadron Collider.

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    CERN/LHC

    Engineers will incorporate more than 20 magnets similar to this model into the next iteration of the LHC, which will take the stage in 2026 and increase the LHC’s luminosity by a factor of ten. That translates into a ten-fold increase in the data rate.

    “Building this magnet prototype was truly an international effort,” says Lucio Rossi, the head of the High-Luminosity (HighLumi) LHC project at CERN. “Half the magnetic coils inside the prototype were produced at CERN, and half at laboratories in the United States.”

    During the original construction of the Large Hadron Collider, US Department of Energy national laboratories foresaw the future need for stronger LHC magnets and created the LHC Accelerator Research Program (LARP): an R&D program committed to developing new accelerator technology for future LHC upgrades.

    MQXF1 quadrupole 1.5-meter prototype magnet sits at Fermilab before testing.
    MQXF1 quadrupole 1.5-meter prototype magnet sits at Fermilab before testing. G. Ambrosio (US-LARP and Fermilab), P. Ferracin and E. Todesco (CERN TE-MSC)

    This 1.5-meter-long model, which is a fully functioning accelerator magnet, was developed by scientists and engineers at Fermilab [FNAL], Brookhaven National Laboratory [BNL], Lawrence Berkeley National Laboratory [LBL], and CERN.

    FNAL II photo
    FNAL

    BNL Logo (2)
    BNL

    LBL Big
    LBL

    CERN
    CERN

    The magnet recently underwent an intense testing program at Fermilab, which it passed in March with flying colors. It will now undergo a rigorous series of endurance and stress tests to simulate the arduous conditions inside a particle accelerator.

    This new type of magnet will replace about 5 percent of the LHC’s focusing and steering magnets when the accelerator is converted into the High-Luminosity LHC, a planned upgrade which will increase the number and density of protons packed inside the accelerator. The HL-LHC upgrade will enable scientists to collect data at a much faster rate.

    The LHC’s magnets are made by repeatedly winding a superconducting cable into long coils. These coils are then installed on all sides of the beam pipe and encased inside a superfluid helium cryogenic system. When cooled to 1.9 Kelvin, the coils can carry a huge amount of electrical current with zero electrical resistance. By modulating the amount of current running through the coils, engineers can manipulate the strength and quality of the resulting magnetic field and control the particles inside the accelerator.

    The magnets currently inside the LHC are made from niobium titanium, a superconductor that can operate inside a magnetic field of up to 10 teslas before losing its superconducting properties. This new magnet is made from niobium-three tin (Nb3Sn), a superconductor capable of carrying current through a magnetic field of up to 20 teslas.

    “We’re dealing with a new technology that can achieve far beyond what was possible when the LHC was first constructed,” says Giorgio Apollinari, Fermilab scientist and Director of US LARP. “This new magnet technology will make the HL-LHC project possible and empower physicists to think about future applications of this technology in the field of accelerators.”

    High-Luminosity LHC coil
    High-Luminosity LHC coil similar to those incorporated into the successful magnet prototype shows the collaboration between CERN and the LHC Accelerator Research Program, LARP.
    Photo by Reidar Hahn, Fermilab

    This technology is powerful and versatile—like upgrading from a moped to a motorcycle. But this new super material doesn’t come without its drawbacks.

    “Niobium-three tin is much more complicated to work with than niobium titanium,” says Peter Wanderer, head of the Superconducting Magnet Division at Brookhaven National Lab. “It doesn’t become a superconductor until it is baked at 650 degrees Celsius. This heat-treatment changes the material’s atomic structure and it becomes almost as brittle as ceramic.”

    Building a moose-sized magnet from a material more fragile than a teacup is not an easy endeavor. Scientists and engineers at the US national laboratories spent 10 years designing and perfecting a new and internationally reproducible process to wind, form, bake and stabilize the coils.

    “The LARP-CERN collaboration works closely on all aspects of the design, fabrication and testing of the magnets,” says Soren Prestemon of the Berkeley Center for Magnet Technology at Berkeley Lab. “The success is a testament to the seamless nature of the collaboration, the level of expertise of the teams involved, and the ownership shown by the participating laboratories.”

    This model is a huge success for the engineers and scientists involved. But it is only the first step toward building the next big supercollider.

    “This test showed that it is possible,” Apollinari says. “The next step is it to apply everything we’ve learned moving from this prototype into bigger and bigger magnets.”

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.


     
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