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  • richardmitnick 3:34 pm on May 22, 2016 Permalink | Reply
    Tags: Accelerator Science, , , , , ,   

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

    Huffington Post
    The Huffington Post

    David Freeman

    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.

    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.


    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: Accelerator Science, , , , , ,   

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


    May 20, 2016
    Ian O’Neill, Discovery News

    A display of a proton-proton collision taken in the LHCb detector in the early hours of May 9.
    Credit: 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 11:07 am on May 19, 2016 Permalink | Reply
    Tags: Accelerator Science, , , , The Biggest Hopes Of What A New Particle At The LHC Might Reveal   

    From Ethan Siegel: “The Biggest Hopes Of What A New Particle At The LHC Might Reveal” 

    Starts with a Bang

    May 18, 2016
    Ethan Siegel

    Inside the magnet upgrades on the LHC, that have it running at nearly double the energies of the first (2010-2013) run. Image credit: Richard Juilliart/AFP/Getty Images.

    Built over an 11-year period from 1998 to 2008, the Large Hadron Collider was designed with one goal in mind: to create the greatest numbers of the highest-energy collisions ever, in the hopes of finding new fundamental particles and of revealing new secrets of nature.

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

    Over a three year period from 2010 to 2013, the LHC collided protons together at energies nearly four times the previous record, with an upgrade nearly doubling that in 2015: to a record 13 TeV, or approximately 14,000 times the energy inherent to a proton via Einstein’s E = mc^2. The largest, most advanced detectors of all — CMS and ATLAS — were built around the main two collision points, collecting as precise and accurate data about all the debris that emerges each time two protons smash together.

    CERN/CMS Detector
    CERN/CMS detector

    CERN/ATLAS detector
    CERN/ATLAS detector

    July 2012 was a watershed moment for particle physics, as enough high-energy collisions were reconstructed to definitively announce, in both detectors, the first concrete, direct evidence for the Higgs Boson: the last undiscovered particle in the Standard Model of particle physics.

    CERN ATLAS Higgs Event
    CERN ATLAS Higgs Event

    CERN CMS Higgs Event
    CERN CMS Higgs Event

    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

    Image credit: The CMS Collaboration, “Observation of the diphoton decay of the Higgs boson and measurement of its properties”, (2014). This was the first “5-sigma” detection of the Higgs.

    But that was expected. The problem is, there are a whole host of questions about the Universe that the Standard Model of particle physics doesn’t answer at a fundamental level, including:

    Why is there more matter than antimatter in the Universe?
    What is dark matter, and what particle(s) beyond the Standard Model (which cannot account for it) explains it?
    Why does our Universe have dark energy, and what is its nature?
    Why don’t the strong interactions in the Standard Model exhibit CP-violation in the strong decays?

    Why do neutrinos have such small but non-zero masses compared to all the other particles?
    And why do the Standard Model particles have the properties and masses that they do, and not any others?

    And the great hope of the LHC, the real hope, is that we’ll learn something extra, beyond the Standard Model, that helps answer one or more of these questions.

    The particles of the Standard Model, all of which have been detected. Image credit: E. Siegel, from his new book, Beyond The Galaxy.

    With the possible exception of dark energy, all of these problems pretty much require new fundamental particles to explain them. And many of them — the dark matter problem, the matter/antimatter problem, and the mass-of-the-particles problem (a.k.a. the Hierarchy problem) — may actually be within reach at the LHC. One way to look for this new physics is to look for deviations from the expected (and well-calculated) behavior in the decays and other properties of the known, detectable Standard Model particles. So far, to the best of our abilities, everything falls within the “normal” range, where things are perfectly consistent with the Standard Model.

    Image credit: The ATLAS collaboration, 2015, of the various decay channels of the Higgs. The parameter mu = 1 corresponds to a Standard Model Higgs only. Via https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/CONFNOTES/ATLAS-CONF-2015-007/.

    But the second way is even better: to discover, directly, evidence for a new particle beyond the Standard Model. As the LHC begins collecting even higher-energy data and with even greater numbers of collisions-per-second, it’s in the best position it’s ever going to be to find new fundamental particles; particles it never expected to find. Of course, it doesn’t exactly find particles; it finds the decay products of particles! Fortunately, because of how physics works, we can reconstruct what energy (and hence, what mass) those particles were created at, and whether we’ve got a new particle after all. At the end of the LHC’s initial run, there’s an intriguing (but not certain) hint of what might be a new particle. This “750 GeV diphoton bump” might not be real, but if it is, it could mean the world to physicists everywhere.

    The ATLAS and CMS diphoton bumps, displayed together, clearly correlating at ~750 GeV. Image credit: CERN, CMS/ATLAS collaborations, image generated by Matt Strassler at https://profmattstrassler.com/2015/12/16/is-this-the-beginning-of-the-end-of-the-standard-model/.

    The preliminary signal is discernible in both the CMS and the ATLAS detectors so far, and that makes the possibility extra tantalizing. Within about 6 more months, we should know whether this signal is strengthening — and hence likely real — or whether it shows itself to be spurious. If it’s real, here are some of the top possibilities:

    1. It’s a second Higgs boson! Many extensions to the Standard Model — like supersymmetry — predict additional Higgs particles that are heavier than the current (126 GeV) one we know. If so, this could be a window into a whole world of physics beyond the Standard Model, including into the matter/antimatter asymmetry and the Hierarchy problem.
    2. It’s dark matter-related. Could this new particle be a window into the dark sector? Is there some energy non-conservation happening here that means we’re making something that the detectors can’t see? This is one of the “dare-to-dream” possibilities of particle physics: that the LHC could create dark matter. There’s even a fun little correlation here with something most people haven’t put together: there’s an excess in cosmic ray energies seen in this exact same energy range from the balloon-borne Advanced Thin Ionization Calorimeter (ATIC) experiment!

    Image credit: J. Chang et al. (2008), Nature, from the Advanced Thin Ionization Calorimeter (ATIC).

    3.It’s a window into extra dimensions. If there are more than the three spatial dimensions we’re used to, especially at smaller scales, new particles can arise in our three dimensions as a result. These Kaluza-Klein particles could show up at the LHC, and might decay to two photons. Studying how they decay could tell us whether this is true.

    4.It’s a new part of the neutrino sector. This would be a little unusual — since neutrinos don’t normally decay to two photons; they’ve got the wrong spin — but a scalar neutrino could create two photons, which is actually a thing in Standard Model extensions. The couplings and decay pathways, if it’s real, could show us this.

    5. It’s a composite particle. The first particle we ever saw decay into two photons was the lightest quark-antiquark combination of all: the neutral pion. Perhaps these Standard Model particles are combining in ways we don’t yet understand, and what we’ve found is nothing new.
    Or, most excitingly, none of the above. The most exciting discoveries are the ones you never anticipated, and perhaps it isn’t any of the speculative scenarios we know to look for. Perhaps nature is more surprising than even our wildest theoretical dreams.

    6. Or, most excitingly, none of the above. The most exciting discoveries are the ones you never anticipated, and perhaps it isn’t any of the speculative scenarios we know to look for. Perhaps nature is more surprising than even our wildest theoretical dreams.

    The answers, believe it or not, are locked inside of the smallest particles in nature. All we need are the highest energies we can get to in order to find out.

    Of course, this could simply turn out to be a statistically insignificant bump that goes away with more data; it may be nothing at all. This has already happened once before, at about three times the energy. There was hint of an extra “bump” at just over 2 TeV in both detectors, as you can see for yourself.

    Images credit: ATLAS collaboration (L), via http://arxiv.org/abs/1506.00962; CMS collaboration (R), via http://arxiv.org/abs/1405.3447.

    A reanalysis of the data shows there’s no significance to this signal, and that might be what we have in the 750 GeV case, too. But the possibility that it’s real is too big to ignore, and the data will come in to tell us by the end of this year. The biggest unanswered, fundamental questions in theoretical physics will get a run for the money, and all it takes is for a bump in the data to hold up a little bit longer.

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    “Starts With A Bang! is a blog/video blog about cosmology, physics, astronomy, and anything else I find interesting enough to write about. I am a firm believer that the highest good in life is learning, and the greatest evil is willful ignorance. The goal of everything on this site is to help inform you about our world, how we came to be here, and to understand how it all works. As I write these pages for you, I hope to not only explain to you what we know, think, and believe, but how we know it, and why we draw the conclusions we do. It is my hope that you find this interesting, informative, and accessible,” says Ethan

  • richardmitnick 4:33 pm on May 17, 2016 Permalink | Reply
    Tags: Accelerator Science, , ,   

    From CERN: “How to help CERN to run more simulations” 

    Cern New Bloc

    Cern New Particle Event

    CERN New Masthead


    16 May 2016
    by The LHC@home team

    With LHC@Home you can actively contribute to the computing capacity of the Laboratory!

    LHC Sixtrack

    You may think that CERN’s large Data Centre and the Worldwide LHC Computing Grid have enough computing capacity for all the Laboratory’s users. However, given the massive amount of data coming from LHC experiments and other sources, additional computing resources are always needed, notably for simulations of physics events, or accelerator and detector upgrades.

    This is an area where you can help, by installing BOINC and running simulations from LHC@home on your office PC or laptop. These background simulations will not disturb your work, as BOINC can be configured to automatically stop computing when your PC is in use.

    BOINC WallPaper


    As mentioned in earlier editions of the Bulletin (see here and here), contributions from LHC@home volunteers have played a major role in LHC beam simulation studies.

    LHC@Home Classic Users 133,627 Hosts (computers) 359,237 Teams 5,079 Countries 205 Total BOINC credit 4,797,971,717
    Last day 205,687
    (Statistics from BOINCStats)

    The computing capacity they made available corresponds to about half the capacity of the CERN batch system! Thanks to this precious contribution, detailed studies of subtle effects related with non-linear beam dynamics have been performed using the SixTrack code. This proved extremely useful not only for the LHC, but also for its upgrade, the HL-LHC.

    More recently, thanks to virtualisation, the use of LHC@home has been expanded to other applications. Full physics simulations are run in a small CernVM virtual machine on all types of volunteer computers. Monte-Carlo simulations for theorists were first included in a project called Test4Theory. Results are submitted to a database called MCPLots, based in the Theory department at CERN. Since 2011, about 2.7 trillion events have been simulated.

    Following this success, ATLAS became the first experiment to join, and the number of volunteers engaged in ATLAS physics events simulation has been steadily ramping up for the last 18 months. The production rate is now equivalent to that of a large WLCG Tier 2 site! These events are fully integrated into the experiment data management system and are already being used for the physics analysis of Run 2. Now applications for the other LHC experiments are also being tested under LHC@home.

    We encourage you to help to produce more results. It is really easy to join! On a standard CERN NICE PC, you can install BOINC with CMF, and then connect to LHC@home as indicated on the LHC@home web-site and in the CMF instructions. If you use a Macintosh or Linux desktop, please refer to the instructions for your platform on the website, which also includes a video tutorial.

    Help our accelerator and research community and join LHC@home!

    [This subject is near and dear to my heart. For about six years I was a “cruncher”. I worked on Six Track and Test4Theory for CERN. In total, all projects I amassed 37,000,000 credits before I had to quit. I still believe in Public Distributed Computing. I support BOINC and World Community Grid on this blog when something is published.]

    See the full article here.

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    Meet CERN in a variety of places:

    Cern Courier




    CERN CMS New

    CERN LHCb New II


    CERN LHC Map
    CERN LHC Grand Tunnel

    CERN LHC particles

    Quantum Diaries

  • richardmitnick 1:52 pm on May 13, 2016 Permalink | Reply
    Tags: Accelerator Science, , , , , ,   

    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

    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/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.

    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 1:03 pm on May 13, 2016 Permalink | Reply
    Tags: Accelerator Science, , , , quasiparticle collider   

    From NOVA: “Quasiparticle Collider Could Illuminate Mysteries of Superconductivity” 



    When a marten—a small, weasel-like animal—crawled inside a transformer and shut down the Large Hadron Collider, it highlighted the risks of giant science experiments. The bigger the facility, the more chances for the unexpected. Physicists use the Large Hadron Collider (LHC), a 17-mile vacuum tube buried under Geneva, Switzerland, to speed up subatomic particles to near the speed of light and smash them together.

    CERN/LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC, 17 mile circular accelerator at CERN

    But a team of scientists has developed a marten-proof way to collide particles—using a device the size of a tabletop.

    Made up of no more than a laser and a tiny crystal, the technique studies different kinds of particles than the LHC does. They’re called quasiparticles. Quasiparticles are, in essence, disturbances that form in a material that can be classified—and modeled—as particles in their own right (even though they are not actual particles). For example, an electron quasiparticle is made up of an electron moving through a medium (in this particular study, a semiconductor crystal), plus the perturbations its negative charge causes in neighboring electrons and atomic nuclei.

    A quantum dot—a nanoscale semiconductor device that tightly packs electrons and electron holes—glows a specific color when it is hit with any kind of light. The team’s new quasiparticle collider could help scientists develop more efficient light-emitting tools, beyond what the quantum dot can do.

    Another example of a quasiparticle that acts as a counterpart to the electron quasiparticle is an electron hole, defined as the lack of electrons in a space surrounded by electrons. In other words, a “hole” quasiparticle is equivalent to a positively charged gap left by an electron on-the-go. So although quasiparticles a little different from what we usually think of as a particle, they’re sort of like air bubbles moving through water. Here’s Elizabeth Gibney, reporting for Nature News:

    It is intuitive for physicists to think in terms of quasiparticles, in the same way that it makes sense to follow a moving bubble in water, rather than trying to chart every molecule that surrounds it, says Mackillo Kira, a physicist at the University of Marburg in Germany and co-author of a report on the quasiparticle collider, published in Nature.

    Usually, the electron quasiparticle and the hole quasiparticle are bound up as a compound quasiparticle called an exciton. Their opposite charges pull them together. But with powerful laser pulses, physicists can cleave the exciton back into its component parts, which rush away from each other. Then they swing back and collide at high speed, producing light particles called photons. The physicists are able to detect the photons, which let them study what happened in the quasiparticle collision.

    Those photons could hold the secrets of how quasiparticles are structured. Though they’re only around for tiny fractions of a second, quasiparticles are an important part of physics. Since quasiparticles form when light is emitted, the new technique could illuminate a way to build better solar cells or to study strange forms of matter such as superconductors, since so-called Bogoliubov quasiparticles represent half of the electron pairs required for superconductivity.

    See the full article here .

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    NOVA is the highest rated science series on television and the most watched documentary series on public television. It is also one of television’s most acclaimed series, having won every major television award, most of them many times over.

  • richardmitnick 3:39 pm on May 12, 2016 Permalink | Reply
    Tags: Accelerator Science, , ,   

    From JLab: “Award enables research for more efficient accelerators” 

    May 12, 2016
    Kandice Carter
    Jefferson Lab Public Affairs

    A furnace system designed by Jefferson Lab Staff Scientist Grigory Eremeev and his colleagues adds tin to the inside surface of niobium cavities. A niobium test cavity and tin are placed inside and heated up to 1200 degrees Celsius. At that temperature, the tin is vaporized by the heat. The tin vapor bonds to the inner surface of the niobium cavity, producing a layer of niobium-tin that is just a few thousandths of a millimeter thick.

    Grigory Eremeev wants to double the efficiency of some of the most efficient particle accelerators being used for research. Now, the staff scientist at the Department of Energy’s Thomas Jefferson National Accelerator Facility has just been awarded a five-year grant through DOE’s Early Career Research Program to do just that.

    Managed by the DOE’s Office of Science, the program provides support to exceptional researchers during the crucial early career years, when many scientists do their most formative work. Eremeev is one of 49 awardees this year, which includes 22 from the National Labs and 27 from universities. His award includes $500K per year for five years.

    “We invest in promising young researchers early in their careers to support lifelong discovery science to fuel the nation’s innovation system,” said Cherry Murray, director of DOE’s Office of Science. “We are proud of the accomplishments these young scientists already have made, and look forward to following their achievements in years to come.”

    Eremeev works with accelerator components made of a metal called niobium. Niobium is a shiny silver metal that becomes a superconductor when chilled to just a few degrees above absolute zero.

    For use in an accelerator, the niobium is formed into specially shaped accelerating structures called cavities. Niobium cavities harness and impart energy onto particles, thereby “accelerating” the particles for use in nuclear physics experiments for exploring the particles inside the nucleus of the atom.

    Superconducting niobium cavities can store energy with almost no losses, allowing the structures to accelerate a continuous beam of particles. Jefferson Lab’s Continuous Electron Beam Accelerator Facility was the first large-scale accelerator to use this technology.

    Jlab CEBAF
    Jlab CEBAF

    Because of its efficiency, CEBAF has been used to conduct many experiments in the nucleus of the atom that weren’t thought possible before, and a recent upgrade of the machine has taken advantage of new technology advances, yielding even more efficient accelerator cavities.

    But Eremeev thinks that these structures can be further improved, so he and his colleagues are looking at ways to optimize the preparation of these structures to coax improved performance from them.

    “We are trying new techniques to reach the potential of the material. So, we are trying different parameters to get better performance,” Eremeev says.

    One of the most promising new parameters that Eremeev and his colleagues are testing is the addition of other superconducting metals to the surface of niobium accelerator cavities, such as tin. Like niobium, tin is a shiny metal that becomes superconducting when cooled to low temperatures. The researchers are working to mix tin with the surface layer of niobium on the inside of the cavities to produce a thin layer of niobium-tin (called Nb3Sn). It’s thought that this alloy will provide a more efficient superconducting surface than pure niobium.

    Eremeev and his colleagues designed and constructed a furnace system to add tin to the inside surface of niobium cavities. A niobium cavity and tin are placed inside and heated up to 1200 degrees Celsius. At that temperature, the tin is vaporized by the heat. The tin vapor bonds to the inner surface of the niobium cavity, producing a layer of niobium-tin that is just a few thousandths of a millimeter thick.

    Eremeev says the niobium-tin cavities have already shown great promise in initial testing.

    “We want to understand and push the limits of the niobum-tin, trying to approach, as close as we can, the performance limitation of the superconductor,” he says.

    For instance, the niobium-tin cavities will stay superconducting at twice the temperatures that are needed for pure niobium accelerating cavities, which could provide significant operational cost savings for future accelerators using the technology.

    In the 12 GeV CEBAF, for instance, the niobium cavities must be kept near 2 Kelvin (-456 degrees Fahrenheit) when operating, which requires 10 MW of power to refrigerate. At double that temperature, 4 Kelvin, there is the potential to only require 6.5 MW of power, a significant savings.

    So far, tests of this new type of accelerator cavity have been limited to R&D units. Eremeev says the next step is to produce two full-size cavities and install them in a section of accelerator for testing under real-world operating conditions, a goal that is now made possible by the DOE Early Career Research Program grant.

    “We need to demonstrate it in a CEBAF five-cell cavity to show that it works,” he says.

    Jefferson Lab is a world-leading nuclear physics research laboratory devoted to the study of the building blocks of matter inside the atom’s nucleus – quarks and gluons – that make up 99 percent of the mass of our visible universe. Jefferson Science Associates, LLC, a joint venture of the Southeastern Universities Research Association, Inc. and PAE Applied Technologies, manages and operates the Thomas Jefferson National Accelerator Facility, or Jefferson Lab, for the U.S. Department of Energy’s Office of Science.

    DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, visit science.energy.gov.

    See the full article here .

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    Thomas Jefferson National Accelerator Facility is managed by Jefferson Science Associates, LLC for the U.S. Department of Energy

    JLab campus

  • richardmitnick 6:49 am on May 10, 2016 Permalink | Reply
    Tags: Accelerator Science, , , ,   

    From Cern Atlas: “ATLAS continues to explore the 13 TeV frontier” 

    CERN ATLAS Higgs Event


    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!”

    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 10:43 am on May 2, 2016 Permalink | Reply
    Tags: Accelerator Science, , , , ,   

    From phys.org: “Physicists abuzz about possible new particle as CERN revs up” 


    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/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 7:57 am on April 14, 2016 Permalink | Reply
    Tags: Accelerator Science, , , ,   

    From FNAL’s Don Lincoln on livescience: “Collider Unleashed! The LHC Will Soon Hit Its Stride” 


    April 12, 2016

    FNAL Don Lincoln
    Don Lincoln, Senior Scientist, Fermi National Accelerator Laboratory; Adjunct Professor of Physics, University of Notre Dame

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

    If you’re a science groupie and would love nothing better than for a cornerstone scientific theory to be overthrown and replaced with something newer and better, then 2016 might well be your year. The world’s largest particle accelerator, the Large Hadron Collider (LHC), is resuming operations after a pause during the winter months, when the cost for electricity in France is highest.

    So why is it such a big deal that LHC coming back on line? It’s because this is the year the accelerator will operate at something approaching its design specifications. Scientists will smash the gas pedal to the floor, crank the fire hose wide open, spin the amplifier button to eleven or enact whatever metaphor you like. This year is the first real year of full-scale LHC operations.

    A particle smasher reborn

    Now if you actually are a science groupie, you know what the LHC is and have probably heard about some of its accomplishments. You know it smashes together two beams of protons traveling at nearly the speed of light. You know scientists using the LHC found the Higgs boson.

    CERN ATLAS Higgs Event
    CERN ATLAS Higgs Event

    CERN CMS Higgs Event
    CERN CMS Higgs Event

    You know that this marvel is the largest scientific device ever built.

    So what’s different now? Well, let’s go back in time to 2008, when the LHC circulated its first beams. At the time, the world’s premier particle accelerator was the U.S. Department of Energy’s Fermilab Tevatron, which collided beams at a whopping 2 trillion electron volts (TeV) of energy and with a beam brightness of about 2 × 1032 cm-2 s-1.

    FNAL/Tevatron map
    FNAL/Tevatron map

    FNAL/Tevatron CDF
    FNAL/Tevatron CDF detectorFNAL/DZero detector
    FNAL/DZero detector

    The technical term for beam brightness is “instantaneous luminosity,” and basically it’s a density. More precisely, when a beam passes through a target, the instantaneous luminosity (L) is the number of particles per second in a beam that pass a location (ΔNB/Δt) divided by the area of the beam (A), multiplied by the number of targets (NT), L = ΔNB/Δt × (1/A) × NT. (And the target can be another beam.)

    The simplest analogy that will help you understand this quantity is a light source and a magnifying glass. You can increase the “luminosity” of the light by turning up the brightness of the light source or by focusing the light more tightly. It is the same way with a beam. You can increase the instantaneous luminosity by increasing the number of beam or target particles, or by concentrating the beam into a smaller area.

    The LHC was built to replace the Tevatron and trounce that machine’s already-impressive performance numbers.

    [If our USA Congress was not filled with idiots, we would have built in Texas the Superconducting Super Collider and not lost this HEP race.]

    The new accelerator was designed to collide beams at a collision energy of 14 TeV and to have a beam brightness — instantaneous luminosity — of at least 100 × 1032 cm-2 s-1. So the beam energy was to be seven times higher, and the beam brightness would increase 50- to 100-fold.

    Sadly, in 2008, a design flaw was uncovered in the LHC when an electrical short caused severe damage, requiring two years to repair . Further, when the LHC actually did run, in 2010, it operated at half the design energy (7 TeV) and at a beam brightness basically the same as that of the Fermilab Tevatron. The lower energy was to give a large safety margin, as the design flaw had been only patched, not completely reengineered.

    The situation improved in 2011 when the beam brightness got as high as 30 × 1032 cm-2 s-1, although with the same beam energy. In 2012, the beam energy was raised to 8 TeV, and the beam brightness was higher still, peaking at about 65 × 1032 cm-2 s-1.

    The LHC was shut down during 2013 and 2014 to retrofit the accelerator to make it safe to run at closer to design specifications. The retrofits consisted mostly of additional industrial safety measures that allowed for better monitoring of the electrical currents in the LHC. This helps ensure there are no electrical shorts and that there is sufficient venting. The venting guarantees no catastrophic ruptures of the LHC magnets (which steer the beams) in the event that cryogenic liquids — helium and nitrogen — in the magnets warm up and turn into a gas. In 2015, the LHC resumed operations, this time at 13 TeV and with a beam brightness of 40 × 1032 cm-2 s-1.

    So what’s expected in 2016?

    The LHC will run at 13 TeV and with a beam brightness that is expected to approach 100 × 1032 cm-2 s-1 and possibly even slightly exceed that mark. Essentially, the LHC will be running at design specifications.

    In addition, there is a technical change in 2016. The protons in the LHC beams will be spread more uniformly around the ring, thus reducing the number of protons colliding simultaneously, resulting in better data that is easier to interpret.

    At a technical level, this is kind of interesting. A particle beam isn’t continuous like a laser beam or water coming out of a hose. Instead, the beam comes in a couple of thousand distinct “bunches.” A bunch looks a little bit like a stick of uncooked spaghetti, except it is about a foot long and much thinner — about 0.3 millimeters, most of the time. These bunches travel in the huge 16-mile-long (27 kilometers) circle that is the LHC, with each bunch separated from the other bunches by a distance that (until now) has been about 50 feet (15 meters).

    The technical change in 2016 is to take the same number of beam protons (roughly 3 × 1014 protons) and split them up into 2,808 bunches, each separated not by 50 feet, but by 25 feet (7.6 m). This doubles the number of bunches, but cuts the number of protons in each bunch in half. (Each bunch contains about 1011 protons.)

    Because the LHC has the same number of protons but separated into more bunches, that means when two bunches cross and collide in the center of the detector, there are fewer collisions per crossing. Since most collisions are boring and low-energy affairs, having a lot of them at the same time that an interesting collision occurs just clutters up the data.

    Ideally, you’d like to have only an interesting collision and no simultaneous boring ones. This change of bunch separation distance from 50 feet to 25 feet brings the data collection closer to ideal.

    Luminous beams

    Another crucial design element is the integrated beam. Beam brightness (instantaneous luminosity) is related to the number of proton collisions per second, while integrated beam (integrated luminosity) is related to the total number of collisions that occur as the two counter-rotating beams continually pass through the detector. Integrated luminosity is something that adds up over the days, months and years.

    The unit of integrated luminosity is a pb-1. This unit is a bit confusing, but not so bad. The “b” in “pb” stands for a barn (more on that in a moment). A barn is 10-24 cm2. A picobarn (pb) is 10-36 cm2. The term “barn” is a unit of area and comes from another particle physics term called a cross section, which is related to how likely it is that two particles will interact and generate a specific outcome. Two objects that have large effective area will interact easily, while objects with a small effective area will interact rarely.

    An object with an area of a barn is a square with a length of 10-12 cm. That’s about the size of the nucleus of a uranium atom.

    During World War II, physicists at Purdue University in Indiana were working with uranium and needed to mask their work for security reasons. So they invented the term “barn,” defining it as an area about the size of a uranium nucleus. Given how big this area is in the eyes of nuclear and particle physicists, the Purdue scientists were co-opting the phrase “as big as a barn.” In the luminosity world, with its units of (1/barn), small numbers mean more luminosity.

    This trend is evident in the integrated luminosity seen in the LHC each year as scientists improved their ability to operate the accelerator. The integrated luminosity in 2010 was 45 pb-1. In 2011 and 2012, it was 6,100 pb-1 and 23,300 pb-1, respectively. As time went on, the accelerator ran more reliably, resulting in far higher numbers of recorded collisions.

    Because the accelerator had been re-configured during the 2013 to 2014 shutdown, the luminosity was lower in 2015, coming in at 4,200 pb-1, although, of course, at the much higher beam energy. The 2016 projection could be as high as 35,000 pb-1. The predicted increase merely reflects the accelerator operators’ increased confidence in their ability to operate the facility.

    This means in 2016, we could actually record eight times as much data as we did in 2015. And it is expected that 2017 will bring even higher performance.

    Illuminating new science

    Let’s think about what these improvements mean. When LHC first collided beams, in 2010, the Higgs boson was still to be observed.

    Higgs Boson Event
    Higgs Boson Event

    On the other hand, the particle was already predicted, and there was good circumstantial evidence to expect that the Higgs would be discovered. And, without a doubt, it must be admitted that the discovery of the Higgs boson was an enormous scientific triumph.

    But confirming previously predicted particles, no matter how impressive, is not why the LHC was built.

    Scientists’ current theory of the particle world is called the Standard Model, and it was developed in the late 1960s, half a century ago.

    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

    While it is an incredibly successful theory, it is known to have holes. Although it explains why particles have mass, it doesn’t explain why some particles have more mass than others. It doesn’t explain why there are so many fundamental particles, given that only a handful of them are needed to constitute the ordinary matter of atoms and puppies and pizzas. It doesn’t explain why the universe is composed solely of matter, when the theory predicts that matter and antimatter should exist in equal quantities. It doesn’t identify dark matter, which is five times more prevalent than ordinary matter and is necessary to explain why galaxies rotate in a stately manner and don’t rip themselves apart.

    When you get right down to it, there is a lot the Standard Model doesn’t explain. And while there are tons of ideas about new and improved theories that could replace it, ideas are cheap. The trick is to find out which idea is right.

    That’s where the LHC comes in. The LHC can explore what happens if we expose matter to more and more severe conditions. Using Einstein’s equation E = mc2, we can see how the high-collision energies only achievable in the LHC are converted into forms of matter never before seen. We can sift through the LHC data to find clues that point us in the right direction to hopefully figure out the next bigger and more effective theory. We can take another step toward our ultimate goal of finding a theory of everything.

    With the LHC now operating at essentially design spec, we can finally use the machine to do what we built it for: to explore new realms, to investigate phenomena never before seen and, stealing a line from my favorite television show, “to boldly go where no one has gone before.” We scientists are excited. We’re giddy. We’re pumped. In fact, there can be but one way to express how we view this upcoming year:

    See the full article here .

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