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  • richardmitnick 10:51 am on March 27, 2015 Permalink | Reply
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    From FNAL- “Frontier Science Result: CMS Rule of three 

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

    March 27, 2015
    Jim Pivarski

    CERN CMS New
    CMS

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    The three-fold symmetry of electrons, muons and taus may be broken by Higgs decays. (Design adapted from a neolithic spiral and the flag of Sicily.)

    In Rendezvous with Rama, Arthur C. Clarke imagined an artifact built by aliens who have three arms with three fingers each, so everything about it has a three-fold symmetry. One could argue that our fondness for bilateral symmetries (in the design of cars, planes, cathedrals, etc.) comes from the ubiquity of this shape in life on Earth, and creatures from other worlds might have developed differently. However, it is more surprising to find such a pattern imprinted on the universe itself.

    All particles of matter appear in threes: three generations of leptons and three generations of quarks. The second generation is a complete copy of the first with heavier masses, and the third generation is yet another copy. For instance, a muon is a heavy version of an electron, and a tau is a heavy muon. No one knows why matter comes in triplicate like this.

    For quarks, the symmetry isn’t perfect because W bosons can turn quarks of one generation into quarks of another generation. Something else transforms generations of neutrinos. But charged leptons — electrons, muons and taus — appear to be rigidly distinct. Some physicists suspect that we simply haven’t found the particle that mixes them yet.

    Or perhaps we have: Theoretically, the Higgs boson could mix lepton generations the way that the W boson mixes quarks. The Higgs decay modes haven’t all been discovered yet, so it’s possible that a single Higgs could decay into two generations of leptons at once, such as one muon and one tau. CMS scientists searched for muon-tau pairs with the right amount of energy to have come from a Higgs boson, and the results were surprising.

    They saw an excess of events. That is, they considered all the ways that other processes could masquerade as Higgs to muon-tau decays, estimated how many of these spurious events they should expect to find, and found slightly more. The word “slightly” should be emphasized — it is on the border of statistical significance, and other would-be discoveries at this level of significance (and stronger) have been shown to be flukes. On the other hand, if the effect is real, it would start as a weak signal until enough data confirm it.

    Naturally, the physics community is eager to see how this develops. The LHC, which is scheduled to restart soon at twice the energy of the first run, has the potential to produce Higgs bosons at a much higher rate — perhaps enough to determine whether this three-fold symmetry of leptons is broken or not.

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

    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 12:28 pm on March 17, 2015 Permalink | Reply
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    From Symmetry: “Experiments combine to find mass of Higgs” 

    Symmetry

    March 17, 2015
    Sarah Charley

    1
    Illustration by Thomas McCauley and Lucas Taylor, CERN

    The CMS and ATLAS experiments at the Large Hadron Collider joined forces to make the most precise measurement of the mass of the Higgs boson yet.

    CERN CMS New II
    CMS

    CERN ATLAS New
    ATLAS

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC

    On the dawn of the Large Hadron Collider restart, the CMS and ATLAS collaborations are still gleaning valuable information from the accelerator’s first run. Today, they presented the most precise measurement to date of the Higgs boson’s mass.

    “This combined measurement will likely be the most precise measurement of the Higgs boson’s mass for at least one year,” says CMS scientist Marco Pieri of the University of California, San Diego, co-coordinator of the LHC Higgs combination group. “We will need to wait several months to get enough data from Run II to even start performing any similar analyses.”

    The mass is the only property of the Higgs boson not predicted by the Standard Model of particle physics—the theoretical framework that describes the interactions of all known particles and forces in the universe.

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    Standard Model of Particle Physics. The diagram shows the elementary particles of the Standard Model (the Higgs boson, the three generations of quarks and leptons, and the gauge bosons), including their names, masses, spins, charges, chiralities, and interactions with the strong, weak and electromagnetic forces. It also depicts the crucial role of the Higgs boson in electroweak symmetry breaking, and shows how the properties of the various particles differ in the (high-energy) symmetric phase (top) and the (low-energy) broken-symmetry phase (bottom).

    The mass of subatomic particles is measured in GeV, or giga-electronvolts. (A proton weighs about 1 GeV.) The CMS and ATLAS experiments measured the mass of the Higgs to be 125.09 GeV ± 0.24. This new result narrows in on the Higgs mass with more than 20 percent better precision than any previous measurements.

    Experiments at the LHC measure the Higgs by studying the particles into which it decays. This measurement used decays into two photons or four electrons or muons. The scientists used data collected from about 4000 trillion proton-proton collisions.

    By precisely pinning down the Higgs mass, scientists can accurately calculate its other properties—such as how often it decays into different types of particles. By comparing these calculations with experimental measurements, physicists can learn more about the Higgs boson and look for deviations from the theory—which could provide a window to new physics.

    “This is the first combined publication that will be submitted by the ATLAS and CMS collaborations, and there will be more in the future,” says deputy head of the ATLAS experiment Beate Heinemann, a physicist from the University of California, Berkeley, and Lawrence Berkeley National Laboratory.

    ATLAS and CMS are the two biggest Large Hadron Collider experiments and designed to measure the properties of particles like the Higgs boson and perform general searches for new physics. Their similar function allows them to cross check and verify experimental results, but it also inspires a friendly competition between the two collaborations.

    “It’s good to have competition,” Pieri says. “Competition pushes people to do better. We work faster and more efficiently because we always like to be first and have better results.”

    Normally, the two experiments maintain independence from one another to guarantee their results are not biased or influenced by the other. But with these types of precision measurements, working together and performing combined analyses has the benefit of strengthening both experiments’ results.

    “CMS and ATLAS use different detector technologies and different detailed analyses to determine the Higgs mass,” says ATLAS spokesperson Dave Charlton of the University of Birmingham. “The measurements made by the experiments are quite consistent, and we have learnt a lot by working together, which stands us in good stead for further combinations.”

    It also provided the unique opportunity for the physicists to branch out from their normal working group and learn what life is like on the other experiment.

    “I really enjoyed working with the ATLAS collaboration,” Pieri says. “We normally always interact with the same people, so it was a real pleasure to get to know better the scientists working across the building from us.”

    With this groundwork for cross-experimental collaboration laid and with the LHC restart on the horizon, physicists from both collaborations look forward to working together to increase their experimental sensitivity. This will enable them not only to make more precise measurements in the future, but also to look beyond the Standard Model into the unknown.

    See the full article here.

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 1:20 pm on March 12, 2015 Permalink | Reply
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    From Don Lincoln at FNAL: The Detectors at the LHC 

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

    The Large Hadron Collider or LHC is the world’s biggest particle accelerator, but it can only get particles moving very quickly. To make measurements, scientists must employ particle detectors. There are four big detectors at the LHC: ALICE, ATLAS, CMS, and LHCb. In this video, Fermilab’s Dr. Don Lincoln introduces us to these detectors and gives us an idea of each one’s capabilities.

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles

    CERN ALICE New II
    ALICE

    CERN ATLAS New
    ATLAS

    CERN CMS New
    CMS

    CERN LHCb New II
    LHCb

    See the full article here.

    Please help promote STEM in your local schools.

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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 12:46 pm on March 8, 2015 Permalink | Reply
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    From BBC: “LHC restart: ‘We want to break physics'” 

    BBC
    BBC

    4 March 2015
    Jonathan Webb

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    Inside the CMS experiment, the beam pipe is dwarfed by huge cylindrical detectors that will try to capture everything that emerges from the collisions.

    As the Large Hadron Collider (LHC) gears up for its revamped second run, hurling particles together with more energy than ever before, physicists there are impatient. They want this next round of collisions to shake their discipline to its core.

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

    “I can’t wait for the switch-on. We’ve been waiting since January 2013 to have our proton beams back,” says Tara Shears, a particle physics professor from the University of Liverpool.

    Prof Shears is raising her voice over the occasional noise of fork-lift trucks and tools, as well as the constant hum of the huge experimental apparatus behind her: LHCb, one of four collision points spaced around the LHC’s 27km circumference.

    CERN LHCb New II
    LHCb

    All this noise reverberates because we are perched at the side of an imposing cavern, 30 storeys beneath the French-Swiss border.

    The other three experiments – Atlas, CMS and Alice – occupy similar halls, buried elsewhere on this famous circular pipeline.

    CERN ATLAS New
    ATLAS

    CERN ALICE New II
    ALICE

    ‘Everything unravels’

    In mid-March two beams of protons, driven and steered by super-cooled electromagnets, will do full circuits of the LHC in both directions – for the first time in two years. When that happens, there will be nobody between here and ground level. Then in May, if the protons’ practice laps proceed without a hitch, each of the four separate experiments will recommence its work: funnelling those tightly focussed, parallel beams into a head-on collision and measuring the results. For us, now, the other stations on the ring are a 10-20 minute drive away; for the protons, a lap will take less than one ten-thousandth of a second. They have the advantage of travelling a whisker under the speed of light.

    They are moving with so much energy that when they collide, things get hot. Historically hot. “We’re recreating temperatures that were last seen billionths of a second after the Big Bang,” Prof Shears explains. “When you get to this hot temperature, matter dissociates into atoms, and atoms into nuclei and electrons. “Everything unravels to its constituents. And those constituents are what we study in particle physics.”

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    The two beams of protons are focussed into a tiny, intense blast before being put on a collision course

    Alongside more pedestrian items, like electrons, or the quarks that combine to make protons and neutrons, these constituents include the world-famous Higgs boson.

    Higgs Boson Event
    Higgs Event

    This longed-for and lauded particle – the last major ingredient in the Standard Model of particle physics – was detected by the teams at Atlas and CMS in 2012.

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    Then in early 2013, after countless further collisions with valuable but less sensational results, the LHC was wound down for a planned hiatus.

    __________________________________________________________________________________

    What is an electronvolt?

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    Particle accelerators use strong electric fields to speed up tiny pieces of matter
    An electronvolt (eV) is the energy gained by one electron as it accelerates through a potential of one volt
    The LHC reaches particle energies measured in trillions of eV: teraelectronvolts (TeV)
    This is only the energy in the motion of a flying mosquito – per particle
    The LHC beams contain hundreds of trillions of particles, each travelling at 99.99999999% of the speed of light
    In total, an LHC beam has the energy of a TGV high-speed train travelling at 150 km/h

    __________________________________________________________________________________

    Renewed vigour

    The two intervening years have been spent servicing and improving the collider.

    “All the magnets have been surveyed, the connections between them have been X-rayed and strengthened, and all the electrical and cryogenic systems have been checked out and optimised,” Prof Shears says. This effort – between one and two million hours of work, all told – means that the LHC is now ready to operate at its “design energy”. Its initial run, after a dramatic false start in 2008, only reached a maximum collision energy of eight trillion electronvolts. That came after a boost in 2012 and the extra power delivered the critical Higgs observations within a few months.

    When they kick off in May, the proton collisions will be at 13 trillion electronvolts: a leap equivalent to that made by the LHC when it first went into operation and dwarfed the previous peak, claimed by the 6km Tevatron accelerator in the US. “It’s a really significant step in terms of what we might be able to see in the Universe,” says Prof Shears.

    “The design energy is a little higher again, at 14 TeV. We want to make sure that we can run close to it, first of all. If operations there are smooth, then subsequently, after next year, we can put the energy up that last little bit.” Alongside this radical hike in the beams’ energy, the experiments housed at the four collision sites have also had time to upgrade. Some have added extra detectors as well as finishing, mending or improving equipment that was built for the first run.

    Build it up, tear it down

    In a sense, one of the shiniest new items in the LHC’s armoury for Run Two is the Higgs boson. Now that its existence is confirmed and quantified, it can inform the next round of detection and analysis. “It’s a new door – a new tool that we can use to probe what is beyond the Standard Model,” says Dr Andre David, one of the research team working on the CMS experiment. Dr David is driving me from the CMS site, in France, back down the valley between the Jura Mountains and Lake Geneva to the main Cern headquarters. This main site, adjacent to the Atlas experiment, sits on the southern side of the LHC’s great circle and straddles the Swiss border.

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    Data flow: The LHC has immeasurable miles of cables to carry experimental data – as well as better mobile phone signal than you can get at ground level

    He emphasises that the Higgs is much more than the final item on the Standard Model checklist; there is a great deal still to find out about it. “It’s like a new wrench that we still have to work out exactly where to fit.” Prof Shears agrees: “We’ve only had about a thousand or two of these new particles, to try and understand their nature.

    “And although it looks like the Higgs boson that we expect from our theory, there’s still a chance that it might have partners that would then tell us that we’re not looking at our normal theory at all. We’re looking at something deeper and more exotic.”

    That is the central impatience that is itching all the physicists here: they want to find something that falls completely outside what they expect or understand. “The data so far has confirmed that our theory is really really good, which is frustrating because we know it’s not!” Prof Shears says. “We know it can’t explain a lot of the Universe.

    “So instead of trying to test the truth of this theory, what we really want to do now is break it – to show where it stops reflecting reality. That’s the only way we’re going to make progress.”

    In the canteen at Cern headquarters I meet Dr Steven Goldfarb, a physicist and software developer on the Atlas team. His sentiments are similar. “We have a fantastic model – that we hate,” he chuckles. “It has stood up to precision measurements for 50 years. We get more and more precise, and it stands up and stands up. But we hate it, because it doesn’t explain the universe.”

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    Dark matter: present but invisible

    In fact, only about 5% of the universe is accounted for by the Standard Model. Physicists think that the rest is made up of dark energy (70%) and dark matter (25%) – but these are still just proposals without any experimental evidence. Based on how fast galaxies move and spin, we know there is much more stuff in the universe than what we can see with telescopes. One idea for a “new physics” that might allow for more particles, including the mysterious constituents of dark matter, is supersymmetry.

    Supersymmetry standard model
    Standard Model of Supersymmetry

    It has also never been glimpsed in data from the LHC or elsewhere, but remains a popular concept with theorists. Supersymmetry suggests that all the particles we know about have heavier, “super” partners – as yet unseen by science.

    That failure doesn’t faze the theory’s fans, Dr Golfarb explains. “If you say to someone who really likes supersymmetry, ‘Hey, why haven’t we found any of the particles yet?’ they’ll say, ‘We’ve found half of the particles! We just need to find the other half…'”

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    The Standard Model equation is etched in stone outside Cern’s control room – but physicists inside want to find something it can’t explain

    Some of those missing, hypothetical particles – notably the gluino and the neutralino – have been mooted as the most likely first results from LHC Run Two.

    They also make promising candidate building blocks for dark matter. But the researchers are open to other possibilities. Dr Goldfarb says the search need not focus on specific, ghostly particles: “It doesn’t have to be supersymmetry. You can also just look for dark matter. That’s why we build our detectors perfectly hermetically.”

    CMS and Atlas are the two “general-purpose” experiments at the LHC. Both of them have detectors completely surrounding the collision point, so that nothing can escape.

    Well, almost nothing. “You can’t build a neutrino detector – so neutrinos do get out. But we know under what circumstances and how often there ought to be neutrinos. So we can account for the missing energy.” What the team really wants to see is a chunk of missing energy that they categorically cannot account for. “When you see a lot of missing momentum – more than is predicted in standard model – then you may have found a candidate for dark matter,” Dr Goldfarb explains.

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    Antimatter: missing altogether

    Even within the 5% of the universe that we do know about, there is a baffling imbalance. The Big Bang ought to have produced two flavours of particle – matter and antimatter – in equal amounts. When those two types of particle collide, they “annihilate” each other. A lot of that sort of annihilation went on, physicists say, and everything we can see in the universe is just the scraps left behind. But puzzlingly, nearly all of those scraps are of one flavour: matter.

    “You just don’t get antimatter in the universe,” says Prof Shears. “You get it in sci-fi and you get it when things decay radioactively, but there are no good deposits of it around.” This glaring absence is “one of the biggest mysteries we have”, she adds. And it is the primary target of the LHCb experiment.

    There, a series of slab-shaped detectors is waiting to try and pinpoint the difference between the particles and anti-particles that pop out of the proton collisions. Run One did reveal some of those differences – but nothing that could explain the drastic tipping of the universal scales towards matter.

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    The beam pipe runs directly through the middle of the huge, slab-shaped detectors at LHCb

    “We think now that the answer has to lie in some new physics,” says Prof Shears. She hopes the near doubling of the collision energy will offer a peek. “We’ve got a million crazy ideas. All we can do is to keep our options open, to sift through the data – and to look for the unexpected.”

    Gravity gap

    There are other questions, too. Gravity, somewhat alarmingly, is nowhere to be found in the Standard Model. “There’s no gravity on that mug,” says Dr Goldfarb, pointing to an LHC souvenir with the model’s equation emblazoned on its side. “That’s annoying! But there’s no answer in sight.” And there is always the ongoing quest to smash the things we currently think are the smallest in existence, and find smaller ones. Dr Goldfarb calls this “the oldest physics” and imagines a cavewoman – the first physicist – banging rocks together to see what was inside.

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    Final touches at CMS: ‘It’s like you’ve put a ship in the harbour and replaced every single plank’ “We’re still doing that today, and we still wonder what’s inside,” he says. “There’s nothing that discounts the idea that electrons, or quarks, are made up of something else. We just call them fundamental because as far as we know, they are.”

    The extra power in Run Two might produce just this kind of fundamental fruit. “The more energy we have for these collisions, the smaller the bits that we can look at,” says Dr David.

    “The ultimate goal here is to understand what matter is made of.” And the world’s largest laboratory is not just repaired, but renewed and ready for that goal. “It’s like you’ve put a ship in the harbour and replaced every single plank,” Dr David says with pride. “It’s not the same ship. It’s a whole new ship and it’s going on a new adventure.”

    See the full article here.

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  • richardmitnick 4:10 pm on February 17, 2015 Permalink | Reply
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    From AAAS: “Five things scientists could learn with their new, improved particle accelerator” 

    AAAS

    AAAS

    15 February
    Emily Conover

    1
    CMS

    The Large Hadron Collider (LHC) is back, and it’s better than ever.

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC

    The particle accelerator, located at CERN, the European particle physics lab near Geneva, Switzerland, shut down in February 2013, and since then scientists have been upgrading and repairing it and its particle detectors. The LHC will be back up to full speed this May. Yesterday, scientists discussed the new prospects for the LHC at the annual meeting of AAAS (which publishes Science).

    The LHC is the world’s most powerful particle accelerator. Protons blast along its 17-mile (27-kilometer) ring at nearly light speed, colliding at the sites of several particle detectors, which sift through the resulting particle debris. In 2012, LHC’s ATLAS and CMS experiments discovered the Higgs boson with data from the LHC’s first run, thereby explaining how particles get mass.

    CERN ATLAS New
    ATLAS

    CERN CMS New
    CMS

    The revamped LHC will run at a 60% higher energy, with more sensitive detectors, and a higher collision rate. What might we find with the new-and-improved machine? Here are five questions scientists hope to answer:

    1. Does the Higgs boson hold any surprises?

    Now that we’ve found the Higgs boson, there’s still a lot we can learn from it. Thanks to the LHC’s energy boost, it will produce Higgs bosons at a rate five times higher, and scientists will be using the resulting abundance of Higgs to understand the particle in detail. How does it decay? Does it match the theoretical predictions? Anything out of the ordinary would be a boon to physicists, who are looking for evidence of new phenomena that can explain some of the unsolved mysteries of physics.

    2. What is “dark matter”?

    Only 15% of the matter in the universe is the kind we are familiar with. The rest is dark matter, which is invisible to us except for subtle hints, like its gravitational effects on the cosmos. Physicists are clamoring to know what it is. One likely dark matter culprit is a WIMP, or weakly interacting massive particle, which could show up in the LHC. Dark matter’s fingerprints could even be found on the Higgs boson, which may sometimes decay to dark matter. You can bet that scientists will be sifting through their data for any trace.

    3. Will we ever find supersymmetry?

    Supersymmetry, or SUSY, is a hugely popular theory of particle physics that would solve many unanswered questions about physics, including why the mass of the Higgs boson is lighter than naively expected—if only it were true. This theory proposes a slew of exotic elementary particles that are heavier twins of known ones, but with different spin—a type of intrinsic rotational momentum. Higher energies at the new LHC could boost the production of hypothetical supersymmetric particles called gluinos by a factor of 60, increasing the odds of finding it.

    Supersymmetry standard model
    Standard Model of Supersymmetric particles

    4. Where did all the antimatter go?

    Physicists don’t know why we exist. According to theory, after the big bang the universe was equal parts matter and antimatter, which annihilate one another when they meet. This should have eventually resulted in a lifeless universe devoid of matter. But instead, our universe is full of matter, and antimatter is rare—somehow, the balance between matter and antimatter tipped. With the upgraded LHC, experiments will be able to precisely test how matter might differ from antimatter, and how our universe came to be.

    5. What was our infant universe like?

    Just after the big bang, our universe was so hot and dense that protons and neutrons couldn’t form, and the particles that make them up—quarks and gluons—floated in a soup known as the quark-gluon plasma. To study this type of matter, the LHC produces extra-violent collisions using lead nuclei instead of protons, recreating the fireball of the primordial universe. Aided by the new LHC’s higher rate of collisions, scientists will be able to take more baby photos of our universe than ever before.

    See the full article here.

    The American Association for the Advancement of Science is an international non-profit organization dedicated to advancing science for the benefit of all people.

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  • richardmitnick 5:56 am on February 15, 2015 Permalink | Reply
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    From NBC: “After the Higgs, LHC Rounds Up the Unusual Suspects in Particle Physics” 

    NBC News

    NBC News

    February 14th 2015
    Alan Boyle

    Supersymmetry and dark matter, neutralinos, gravitinos and gluinos … you can expect exotic topics like these to be spinning around as the Large Hadron Collider ramps up to smash subatomic particles again over the next couple of months.

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

    Physicists say the first hints of unconventional physics, such as evidence for the existence of those weird-sounding gluinos, could emerge within the next few months. Or not.

    It’s been almost three years since scientists at Europe’s CERN particle physics lab announced that the world’s most powerful collider had found the Higgs boson, a mysterious particle whose existence was predicted almost a half-century earlier. It’s been two years since the LHC was shut down for repairs and upgrades. Now thousands of physicists are getting ready to send beams of protons through the machine for the first time since 2013.

    “The beam is knocking at the door,” Frederick Bordry, CERN’s director for accelerators and technology, said Saturday during a preview of the LHC’s second experimental run at the annual meeting of the American Association for the Advancement of Science, here in San Jose.

    Bordry said the LHC’s supercooled magnets are being prepared for the first proton beams to start circulating around the end of March. Scientific observations would begin after a two-month conditioning period, or by the end of May, he said.

    “Don’t kill me if we are taking three or four days more,” he joked.

    LHC gets an energy boost

    It has taken decades to plan and build the $10 billion Large Hadron Collider and its four main detectors, housed in tunnels that run 300 feet (100 meters) beneath the countryside at the French-Swiss border. Now Bordry and others at CERN have mapped out a schedule of experimental runs and maintenance periods to keep the LHC on the frontier of physics until at least 2035.

    The upcoming run is scheduled to last until 2017. During that time, the LHC will ramp up to smash protons together at 60 percent higher energies than it did at the end of its initial run: 13 trillion electron volts, or 13 TeV, as opposed to 8 TeV. Moreover, the beam luminosity will be three times higher.

    That means the collider’s detectors should be detecting Higgs bosons — particles that are associated with the process that imparts mass to other subatomic particles — at five times the frequency, said Beate Heinemann, a physicist at the University of California at Berkeley and the Berkeley Lab who’s part of the LHC’s ATLAS experimental group.

    CERN ATLAS New
    ATLAS

    Heinemann said the boost in the LHC’s capabilities should also improve scientists’ chances of detecting gluinos, a theoretical particle predicted by supersymmetry theory, by a factor of 60.

    Hints of weirdness

    Heinemann and her colleagues said the collider’s initial three-year run has already pointed to some apparent discrepancies with the Standard Model, the theory that currently holds sway in particle physics. However, those discrepancies have not yet shown up at a confidence level that would persuade scientists that something weird was really going on.

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    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.

    If the weirdness is real, the LHC could provide evidence for it during the upcoming run, perhaps as soon as August or September, Heinemann told reporters.

    The new phenomena could take the form of supersymmetric particles, as-yet-undetected bits of matter that would add an elegant twist to the Standard Model. One such particle could be a gluino, the supersymmetric partner of a known particle called the gluon.

    Other hypothesized supersymmetric particles include neutralinos, which could account for the universe’s mysterious dark matter; and gravitinos, which could help explain dark matter as well as some of the mysteries surrounding gravity. The discrepancies also could be caused by a new breed of fourth-generation quark, Heinemann said.

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    Supersymmetry theory, or SUSY, suggests that each fundamental subatomic particle we’ve detected to date has a yet-to-be-discovered partner with complementary characteristics. The red box highlights the gluino, a particle that physicists believe could be detected at the Large Hadron Collider. If it exists, that is.

    However, there’s also a chance that the apparent discrepancies are nothing more than statistical glitches. That’s what happened a couple of years ago, when physicists saw hints pointing to the existence of a second kind of Higgs boson — only to watch those hints fade away as more readings were taken.

    “When you put a thousand physicists in a room to do data analysis, and each one of them makes 100 or 1,000 data plots, you’re likely to get statistical anomalies now and then — just like monkeys in the room typing out Shakespeare plays. Things happen,” said UCLA physicist Jay Hauser, a member of the LHC’s CMS collaboration.

    CERN CMS New
    CMS

    He said the data anomalies will provide a focus for future observations.

    “If it’s statistics, they’ll probably go away or diminish,” Hauser said. “If it’s real and interesting, then the effect will grow, and we get really excited.”

    Fermilab physicist Don Lincoln discussed the upcoming restart of the Large Hadron Collider — and the discoveries that may lie ahead — with NBC News’ Alan Boyle earlier this month on “Virtually Speaking Science.”

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    Read the pre-show interview, and listen to the hourlong podcast via BlogTalkRadio or iTunes.

    See the full article here.

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  • richardmitnick 11:45 am on February 13, 2015 Permalink | Reply
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    From Symmetry: “What’s new for LHC Run II” 

    Symmetry

    February 13, 2015
    Sarah Charley

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    The most powerful particle accelerator on Earth has been asleep for the past two years. Soon it will reawaken for its second run.

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC

    Since shutting down in early 2013, the LHC and its detectors have undergone a multitude of upgrades and repairs. When the particle accelerator restarts, it will collide protons at an unprecedented energy: 13 trillion electron volts. Scaled up into our macroscopic world, the force of these proton-proton collisions is roughly equivalent to an apple hitting the moon hard enough to create a crater 6 miles across.

    The upgraded capabilities of the ATLAS, CMS, ALICE and LHCb detectors—plus the LHC’s extra boost of power—will give scientists access to a previously inaccessible realm of physics.

    CERN ATLAS New
    ATLAS

    CERN CMS New
    CMS

    CERN ALICE New
    ALICE

    CERN LHCb New
    LHCb

    To the Higgs boson …and beyond!

    In the first run of the LHC, the ATLAS and CMS experiments ended the 50-year hunt for the Higgs boson, which was predicted the Standard Model of particles and forces. Now scientists want to know if the Higgs they found is hiding any surprises.

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    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.

    “All the properties of the Higgs boson are already predicted by the Standard Model, so it’s our job to go out and measure those properties and see if they agree,” says Jay Hauser, a UCLA physicist working on the CMS experiment. “If anything disagrees, it could be a window to new physics.”

    Because the Higgs boson loves mass, scientists suspect that it might interact with a range of hidden, massive particles that we cannot see, such as dark matter. If the Higgs boson is dancing with any undiscovered physics, scientists should see evidence of this in the way the Higgs behaves.

    But even if the Higgs agrees with all predictions, something about it still seems a bit strange.

    “The Higgs mass doesn’t make any sense,” says Beate Heinemann, a Berkeley physicist and the deputy head of the ATLAS experiment. “It would make much more sense if it was much heavier, which is why we think there must be something that protects the Higgs boson and gives it a lower mass.”

    This Higgs bodyguard could be anything from supersymmetric particles to dark matter to extra dimensions.

    Supersymmetry standard model
    Standard Model of Supersymmetry

    “We have quite a few puzzles,” Heinemann says. “We think that there should be new physics at this energy scale, but we don’t know what it is yet.”

    Bringing it back to the big bang

    Scientists on the ALICE experiment have their sights on something else.

    In the beginning, the entire universe—all the stars, planets and galaxies—were part of a hot soup of matter called quark gluon plasma. The LHC can recreate those conditions in miniature by colliding beams of heavy atomic nuclei, which it does for four weeks per year. The ALICE detector specializes in investigating the properties of this primordial material.

    “The quark gluon plasma is so hot that ordinary protons and neutrons cannot exist in it,” says Peter Jacobs, a Berkeley physicist working on the ALICE experiment. “Quarks and gluons move around in it and interact in new ways that we haven’t seen before. It’s a new form of matter and we want to know how it behaves and what its properties are—like its structure and how it acts at different temperatures.”

    In the first run of the LHC, the ALICE experiment was able to characterize many aspects of this weird semi-liquid plasma, such as its viscosity.

    “The quarks and gluons interact more than we originally thought, indicating that the quark-qluon plasma is more like a liquid than a gas; indeed, almost as “perfect” a liquid as nature allows,” Jacobs says.

    But there is still more to investigate.

    “Run I was a discovery run, and we were able to explore many new things and developed a lot of curiosities,” Jacobs says. “During Run II, we will be able to explore these curiosities more deeply and give them quantitative values instead of just being able to describe them qualitatively.”

    The case of the missing antimatter

    Scientists suspect that the big bang acted like a universe-sized supercollider that brought equal parts of matter and antimatter into existence. But where did all of the antimatter go?

    The LHCb experiment is one of the world’s best early-universe detectives and looks for clues in the case of the disappearing antimatter.

    “We should have started with equivalent amount of matter and antimatter in the universe,” says Michael Williams, an MIT physicist working on the LHCb experiment. “But now, all we see is matter, and there is no way the Standard Model can explain this huge discrepancy. There must be some other way matter and antimatter behave differently.”

    To uncover the root of this huge discrepancy, the LHCb experiment does precision measurements of subatomic processes. LHCb scientists then compare the Standard Model predictions with these experimental observations to see how well they match up.

    Thus far, the Standard Model has been hard to break. But Williams thinks that increasing the precision of these measurements could start to show where the cracks are.

    “You never know if you’re on the cusp of making a discovery,” Williams says. “In Run II, we will measure lots of processes with a much higher precision, and this might reveal something that the Standard Model is not explaining.”

    See the full article here.

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 3:59 pm on February 6, 2015 Permalink | Reply
    Tags: , , , CERN LHC, , ,   

    Amazing CERN Photo Essay From NBC News: “World’s Biggest Particle Smasher Gears Up for Next Run” 

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    CERN New Masthead

    After the discovery of the Higgs boson, or “God Particle,” in 2012, Europe’s giant particle accelerator at CERN has been getting an overhaul.

    1
    1. Scientists at the CERN particle physics center at the French-Swiss borders are preparing to restart the Large Hadron Collider (LHC), the world’s most powerful particle-smasher. Photographer Luca Locatelli was given access to maintenance work in November, providing a unique view into this vast underground laboratory. Engineers work on equipment for the LHC in the main workshop at CERN shown here.

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    2. A model of the Large Hadron Collider is displayed inside the LHC Magnet facility building, where components for the particle accelerator are built. The LHC was first started up in 2008 and is resuming high-energy collisions in March.

    3
    3. The LHC’s 17-mile-round underground tunnel directs particles through ATLAS, one of the facility’s two general-purpose detectors. ATLAS and the other detector, the Compact Muon Solenoid [CMS], probe a wide range of scientific mysteries, from the successful search for the Higgs boson to the hunt for extra dimensions and particles that could make up dark matter.

    4
    4. A scientist works inside one of the underground rooms of the Compact Muon Solenoid, another of LHC’s general-purpose detectors. The CMS experiment is one of the largest international scientific collaborations in history, involving 4,300 particle physicists, engineers, technicians, students and support staff from 182 institutes in 42 countries.

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    5. Maintenance work continues inside the CMS. The CMS detector is built around a huge solenoid magnet. This takes the form of a cylindrical coil of superconducting cable that generates a field of 4 tesla, about 100,000 times the strength of Earth’s magnetic field.

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    6. A unusual feature of the CMS detector is that instead of being built in place like the LHC’s other detectors, it was constructed in 15 sections at ground level before being lowered into an underground cavern and assembled. The complete detector is 70 feet long, 50 feet wide and 50 feet high (21 by 15 by 15 meters).

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    7. The last bit of maintenance work is perfomed inside the ALICE (A Large Ion Collider Experiment) before it resumes operation in 2015. ALICE is a heavy-ion detector that’s designed to study the physics of strongly interacting matter at extreme energy densities.

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    8. The ALICE detector sits in a vast cavern almost 200 feet (56 meters) below ground, close to the village of St Genis-Pouilly in France. When ALICE is in operation, the engineers in charge of the LHC switch from using beams of protons to beams of lead ions.

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    9. The ALICE collaboration uses a 10,000-ton detector – 85 feet long, 50 feet high and 50 feet wide (26 by 16 by 16 meters) – to study quark-gluon plasma, the “Big Bang soup” that existed when the universe was a trillionth of a second old.

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    10. In addition to the experiments at the LHC, scientists at the CERN particle physics center conduct huge numbers of smaller experiments. A bird’s-eye view shows one of the experiments in progress.

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    11. The Antiproton Decelerator provides low-energy antiprotons, mainly for studies of antimatter. Previously, “antiparticle factories” at CERN and elsewhere consisted of chains of accelerators, each performing one of the steps needed to provide antiparticles for experiments. Now the Antiproton Decelerator performs all the necessary steps, from making the antiprotons to delivering them to experiments. At CERN, scientists have used the antiprotons to create atoms of antihydrogen for a fraction of a second.

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    12.The 7,000-ton ATLAS detector is the largest particle detector ever constructed in terms of volume. ATLAS and the Compact Muon Solenoid, or CMS, were instrumental in the successful search for the Higgs boson at the Large Hadron Collider.

    And, for good measure, the 2008 video The Big Bang Machine from BBC. This video is from before the LHC started up. But, in my view, it is the best teaching video on both the LHC and
    particle physics involved in its experiments. This video features Sir Dr. Brian Cox, University of Manchester. Brian worked or works on the ATLAS project. He spent some time at FNAL’s Tevatron and does not leave it out as has been done by others. There are more recent videos. They simply do not do as well in communicating this story.


    Watch, enjoy, learn.

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  • richardmitnick 12:05 pm on January 27, 2015 Permalink | Reply
    Tags: , , CERN LHC, , ,   

    From CERN- “LHC Season 2: holding the key to new frontiers” 

    CERN New Masthead

    12 Jan 2015
    Cian O’Luanaigh

    This year, the Large Hadron Collider (LHC) will restart at the record collision energy of 13 TeV, following a two-year long shutdown (LS1) for planned maintenance. To mark this, today saw the LS1 activities coordinator symbolically handing over the LHC key to the operations team. The team will now perform tests on the machine in preparation for the restart this spring.

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC

    After three years of highly successful running, the LHC was shut down for maintenance in 2013. Since then, engineers and technicians have been repairing and strengthening the 27-kilometre accelerator in preparation for its restart at 13 TeV. Some 18 of the 1232 dipole magnets that steer particle beams around the accelerator were replaced, and more than 10,000 electrical interconnections between the magnets were strengthened. The LHC’s vacuum, cryogenics and electronics systems were also consolidated.

    “It’s important to stress that after the long shutdown, the LHC is essentially a new machine,” said CERN Director-General Rolf Heuer in his New Year address at CERN last week.

    The collision energy of 13 TeV is a significant increase compared with the initial three-year LHC run, which began at 7 TeV and rose to 8 TeV. In addition, in the run that starts this year, bunches of protons in the accelerator will collide at briefer intervals – 25 nanoseconds(ns) between them instead of 50 ns – and the beams will be more tightly focused. All these factors are aimed at optimising the delivery of particle collisions for physics research.

    With collisions at energies never reached in a particle accelerator before, the LHC will open a new window for discovery, allowing further studies of the Higgs boson and the potential to address unsolved mysteries such as dark matter.

    The LHC is CERN’s flagship machine, but the accelerator complex also provides a broad programme of research that makes many contributions to fundamental physics. The long shutdown has allowed teams throughout CERN to upgrade experiments, detectors, accelerators and equipment.

    In addition, the laboratory has continued to nurture its collaborations around the world with involvements in future collider studies, showing CERN’s dedication to the future of particle physics at the very forefront of knowledge.

    It will be a busy year ahead, and with so much in store the laboratory looks forward to LHC Season 2 and more!

    See the full article here.

    Please help promote STEM in your local schools.

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    Meet CERN in a variety of places:

    Cern Courier

    THE FOUR MAJOR PROJECT COLLABORATIONS

    ATLAS
    CERN ATLAS New
    ALICE
    CERN ALICE New

    CMS
    CERN CMS New

    LHCb
    CERN LHCb New

    LHC

    CERN LHC New

    LHC particles

    Quantum Diaries

     
  • richardmitnick 9:31 am on January 27, 2015 Permalink | Reply
    Tags: , CERN LHC, , , ,   

    From Huff Post: “The Future of Physics” 

    Huffington Post
    The Huffington Post

    01/26/2015

    Dr. Sten Odenwald, Astronomer, National Institute of Aerospace

    In another few months the Large Hadron Collider. will be powered up to explore its maximum energy range. Many physicists fervently hope we will see definite signs of “new physics,” especially a phenomenon called “supersymmetry.” In the simplest view, the Standard Model souped-up with supersymmetry will offer a massive new partner particle for every known particle (electron, quark, neutrino, etc). One of these, called the neutralino, may even explain dark matter itself!

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

    Supersymmetry standard model
    Standard Model of Supersymmetry

    But Wait, There’s More!

    Supersymmetry is the foundational cornerstone on which string theory rests. That’s why physicists call this “stringy” theory of matter “superstring theory.” If the LHC does not turn up any signs of supersymmetry during the next two or three years, not only will simple modifications to the current Standard Model be ruled out, but the most elegant forms of supersymmetry theory will fall too.

    As an astronomer I am not too worried. The verified Standard Model is now fully capable of accounting for everything we see in the universe since a trillion-trillion-trillionth of a second after the Big Bang to the present time, once you include gravity, and don’t worry too much about dark matter and dark energy.

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    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.

    But we need some explanation for dark energy and dark matter to complete our understanding of the cosmos, and for that we still need our physicist friends to show the way. Currently their only answers involve supersymmetry theory. If this idea falls, astronomers will be completely stumped to explain what governs our universe on the largest scales.

    Beyond supersymmetry, we also have the huge investment of talent that has pursued superstring theory since the early 1980s. Without supersymmetry, the “super” part of string theory also falls, and you end up with a non-super string theory that is clunky, inelegant and pretty dismal in accounting for the finer details of our physical world, often termed “quantum gravity.” A big part of this is the idea that our universe inhabits more than four dimensions — perhaps as many as 11!

    On April 26, 2006, I had the following exchanges with Stanford theoretical physicist Leonard Susskind, who is widely regarded as one of the fathers of string theory, along with other provocative and foundational ideas such as the “holographic universe.” His comments are still relevant seven years later.

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    Odenwald: Why is it so important for physicists to consider the universe having more than four dimensions, as the mathematics of superstring theory seems to require?

    Susskind: Almost all working high-energy theoretical physicists are convinced some sort of extra dimensions are needed to explain the complexity of elementary particles. That particles move in extra dimensions is another way of talking about the fact that they have more complex properties than just position and velocity. It is hard to find a serious paper about particle phenomenology that doesn’t in some way use the tools of superstring theory. Furthermore, we all agree that the origin of elementary particles is most likely at the planck scale and cannot be understood without a good theory of quantum gravity.

    Odenwald: So if superstring theory were found to be an incorrect model for our particular universe, is that like turning the clock back to circa 1978 in physics?

    Susskind: I agree that going back to the ’70s would be turning the clock back in the sense that we would be ignoring the vast amount of mathematical knowledge that has been gained over the subsequent years, mostly from string theory. That is just not going to happen. The changes in our theoretical understanding of quantum field theory, gravity, black holes, are completely irreversible. [String theory mathematics] has even worked its way into nuclear physics and heavy ion collisions as well as into condensed matter physics.

    Odenwald: Kind of a hard place for modern theoreticians to revisit, but for astronomy and cosmology the 1970s seem not such a bad place. Without superstring theory, we would still have cosmological inflation. Without superstring theory, what happened at the instant of the Big Bang would remain unknown, logically indescribable, and still a great puzzle… as it always has.

    Susskind: [Not quite.] Recent cosmology has been completely dominated by studying the cosmic microwave background [CMB] and inflationary theory.

    Cosmic Background Radiation Planck
    CMB per ESA/Planck

    ESA Planck
    ESA/Planck

    Gravitational Wave Background
    Gravitational waves from BICEP2 in support of Inflation theory not yet accepted

    BICEP 2
    BICEP2

    The CMB fluctuation spectrum is widely understood as a quantum effect. Inflation is a gravitational effect. Is there any question that quantum gravity (quantum plus gravity) will be the framework for understanding the early universe? No, there is not. Also I might add that the old inflation that you are referring to was a disaster. It didn’t work. Many inflationary cosmologists like Linde, Vilenkin, and Guth are looking to string theory for possible answers to the puzzles of inflation.

    Odenwald: Is it fair to say that superstring theory is “too big to fail”? I am reminded of the alledged quotation by Einstein as he was awaiting news about a major test of relativity in 1919. A reporter is said to have asked, “Well, what would it mean if your theory is wrong?” to which Einstein allegedly replied, “Then I would feel sorry for the good Lord; the theory is correct!” Is the physics community in the same predicament because superstring theory is a “beautiful” theory that seems to explain so much, and its mathematics is so impeccable that it is used in other theoretical settings in physics?

    Susskind: Exactly right. However, it is fair to say that while theorists were developing powerful tools, they mostly had wrong expectations for what the theory was indicating. Most theorists hoped that string theory would lead to an absolutely unique set of particles, coupling constants, with exactly vanishing cosmological constant. What we have learned from the theory itself is that it is a theory of tremendous diversity. Unexpectedly, string theory is most comfortable with a huge multiverse of tremendous variety instead of the small “knowable” and unique universe we once imagined.

    Odenwald: So what would our theoretical explanations for our universe look like without added dimensions, quantum gravity or string theory?

    Susskind: Without these things the world as we know it couldn’t exist. Giving up quantum gravity means giving up either the ideas of quantum [mechanics] or of gravity [and general relativity]. In a cosmological context quantum gravity is responsible for the primordial density fluctuations [we directly observe in the CMB] that ultimately condensed to form stars, galaxies, planets, etc. Without string theory we should not have the diversity of possibilites that allow pocket universes [Alan Guth’s term] with the ultra-fine tuning needed to insure conditions for our kind of life.

    Odenwald: If string theory loses its experimental support at the LHC, wouldn’t it be far worse than merely going back to cosmology circa 1975 or even 1965? We would have to question the very mathematical tools we have been using for the last 50 years!

    Susskind: I agree with your analysis, except that I would add: Expect the unexpected. Unforseen surprises are the rule in science, not the exception. Remember: Stuff happens.

    Odenwald: If superstring theory falls, are there any competing theories out there that could hold out some hope?

    Susskind: Not as far as I know.

    • * * * *

    So there you have it. The Large Hadron Collider absolutely has to find some clue about supersymmetry, or superstring theory is compromised, we will have no good idea about dark matter, and we will definitely be in a bad place until the super-LHC is built in the 2030s.

    Patience, however, is a still a necessary virtue. Physicists were in this same quandary before the Higgs boson was finally discovered after 50 years of increasingly panicked searching.

    See the full article here.

    Please help promote STEM in your local schools.

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