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Showing posts with label CERN. Show all posts
Showing posts with label CERN. Show all posts

Tuesday, October 11, 2011

LHSee - Large Hadron Collider app - Big bang science in your pocket



Want to find out how to Hunt the Higgs Boson using your phone? Ever wondered how the Large Hadron Collider experiments work, and what the collisions look like?


Scientists at the world's biggest scientific experiment - the Large Hadron Collider (LHC)at CERN, Geneva - are trying to answer fundamental questions about the nature of the Universe, the origin of mass, the structure of space and time, and the conditions of the early universe. For those of us not lucky enough to have the world's highest energy particle smasher in our own back gardens, we can still get close to the action using an exciting new smartphone App.

The new App, called 'LHSee', makes the LHC accessible to anybody with a smartphone or tablet PC running the Google Android operating system. Written by Oxford University scientists in collaboration with the ATLAS, one of the four LHC experiments at CERN, it has been designed for experts and non-experts alike.

For the first time you can now grab live collision events from the underground detectors in Geneva, and beam them direct to your own device. As well as a variety of educational resources, the application allows you to interact with the collision events in full 3D graphics. You can also find out how the different parts of the detector work, learn how to identify different types of collision, and even put your new skills to the test by playing the 'Hunt the Higgs' game.

Dr Alan Barr of the University of Oxford says: "I love the detail in the live displays - it's amazing to see that you can pick out the different individual proton collisions."

With help from their international friends within the ATLAS collaboration, the developers offer the App with language support not just in English, but also in French, German, Italian, Spanish and Swedish.

The App is free to download from the Google Android Marketplace.

Sunday, September 25, 2011

Roll over Einstein: Law of physics challenged


One of the very pillars of physics and Einstein's theory of relativity - that nothing can go faster than the speed of light - was rocked Thursday by new findings from one of the world's foremost laboratories.
This undated file photo shows famed physicist Albert Einstein. Scientists at the European Organization for Nuclear Research, or CERN, the world's largest physics lab, say they have clocked subatomic particles, called neutrinos, traveling faster than light, a feat that, if true, would break a fundamental pillar of science, the idea that nothing is supposed to move faster than light, at least according to Einstein's special theory of relativity: The famous E (equals) mc2 equation. That stands for energy equals mass times the speed of light squared. The readings have so astounded researchers that they are asking others to independently verify the measurements before claiming an actual discovery. (AP Photo)

European researchers said they clocked an oddball type of subatomic particle called a neutrino going faster than the 186,282 miles per second that has long been considered the cosmic speed limit.

The claim was met with skepticism, with one outside physicist calling it the equivalent of saying you have a flying carpet. In fact, the researchers themselves are not ready to proclaim a discovery and are asking other physicists to independently try to verify their findings.

"The feeling that most people have is this can't be right, this can't be real," said James Gillies, a spokesman for the European Organization for Nuclear Research, or CERN, which provided the particle accelerator that sent neutrinos on their breakneck 454-mile trip underground from Geneva to Italy.

Going faster than light is something that is just not supposed to happen according to Einstein's 1905 special theory of relativity - the one made famous by the equation E equals mc2. But no one is rushing out to rewrite the science books just yet.

It is "a revolutionary discovery if confirmed," said Indiana University theoretical physicist Alan Kostelecky, who has worked on this concept for a quarter of a century.

Stephen Parke, who is head theoretician at the Fermilab near Chicago and was not part of the research, said: "It's a shock. It's going to cause us problems, no doubt about that - if it's true."

Even if these results are confirmed, they won't change at all the way we live or the way the world works. After all, these particles have presumably been speed demons for billions of years. But the finding will fundamentally alter our understanding of how the universe operates, physicists said.

Einstein's special relativity theory, which says that energy equals mass times the speed of light squared, underlies "pretty much everything in modern physics," said John Ellis, a theoretical physicist at CERN who was not involved in the experiment. "It has worked perfectly up until now."

France's National Institute for Nuclear and Particle Physics Research collaborated with Italy's Gran Sasso National Laboratory on the experiment at CERN. CERN reported that a neutrino beam fired from a particle accelerator near Geneva to a lab 454 miles (730 kilometers) away in Italy traveled 60 nanoseconds faster than the speed of light. Scientists calculated the margin of error at just 10 nanoseconds. (A nanosecond is one-billionth of a second.)

Given the enormous implications of the find, the researchers spent months checking and rechecking their results to make sure there were no flaws in the experiment.

A team at Fermilab had similar faster-than-light results in 2007, but a large margin of error undercut its scientific significance.

If anything is going to throw a cosmic twist into Einstein's theories, it's not surprising that it's the strange particles known as neutrinos. These are odd slivers of an atom that have confounded physicists for about 80 years.

The neutrino has almost no mass, comes in three different "flavors," may have its own antiparticle and has been seen shifting from one flavor to another while shooting out from our sun, said physicist Phillip Schewe, communications director at the Joint Quantum Institute in Maryland.

Columbia University physicist Brian Greene, author of the book "Fabric of the Cosmos," said neutrinos theoretically can travel at different speeds depending on how much energy they have. And some mysterious particles whose existence is still only theorized could be similarly speedy, he said.



Fermilab team spokeswoman Jenny Thomas, a physics professor at the University College of London, said there must be a "more mundane explanation" for the European findings. She said Fermilab's experience showed how hard it is to measure accurately the distance, time and angles required for such a claim.

Nevertheless, Fermilab, which shoots neutrinos from Chicago to Minnesota, has already begun working to try to verify or knock down the new findings.

And that's exactly what the team in Geneva wants.

Gillies told The Associated Press that the readings have so astounded researchers that "they are inviting the broader physics community to look at what they've done and really scrutinize it in great detail, and ideally for someone elsewhere in the world to repeat the measurements."

Only two labs elsewhere in the world can try to replicate the work: Fermilab and a Japanese installation that has been slowed by the tsunami and earthquake. And Fermilab's measuring systems aren't nearly as precise as the Europeans' and won't be upgraded for a while, said Fermilab scientist Rob Plunkett.

Drew Baden, chairman of the physics department at the University of Maryland, said it is far more likely that the CERN findings are the result of measurement errors or some kind of fluke. Tracking neutrinos is very difficult, he said.

"This is ridiculous what they're putting out," Baden said. "Until this is verified by another group, it's flying carpets. It's cool, but ..."

So if the neutrinos are pulling this fast one on Einstein, how can it happen?

Parke said there could be a cosmic shortcut through another dimension - physics theory is full of unseen dimensions - that allows the neutrinos to beat the speed of light.

Indiana's Kostelecky theorizes that there are situations when the background is different in the universe, not perfectly symmetrical as Einstein says. Those changes in background may alter both the speed of light and the speed of neutrinos.

But that doesn't mean Einstein's theory is ready for the trash heap, he said.

"I don't think you're going to ever kill Einstein's theory. You can't. It works," Kostelecky said. There are just times when an additional explanation is needed, he said.

If the European findings are correct, "this would change the idea of how the universe is put together," Columbia's Greene said. But he added: "I would bet just about everything I hold dear that this won't hold up to scrutiny."


More information: The results are pre-published on ArXiv: http://arxiv.org/abs/1109.4897

Monday, June 6, 2011

Physicists Store Antimatter Atoms for 1,000 Seconds -- And Still Counting



The ALPHA Collaboration, an international team of scientists working at CERN in Geneva, Switzerland, has created and stored a total of 309 antihydrogen atoms, some for up to 1,000 seconds (almost 17 minutes), with an indication of much longer storage time as well.
This is an artistic representation of the ALPHA neutral 
antimatter trap, suggesting the nature of the ALPHA 
apparatus as a container for antihydrogen. (Credit: 
Chukman So, copyright © 2011 Wurtele Research 
Group. All rights reserved.)

ALPHA announced in November, 2010, that they had succeeded in storing antimatter atoms for the first time ever, having captured 38 atoms of antihydrogen and storing each for a sixth of a second. In the weeks following, ALPHA continued to collect anti-atoms and hold them for longer and longer times.

Scientists at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California at Berkeley, including Joel Fajans and Jonathan Wurtele of Berkeley Lab's Accelerator and Fusion Research Division (AFRD), both UC Berkeley physics professors, are members of the ALPHA Collaboration.

Says Fajans, "Perhaps the most important aspect of this result is that after just one second these antihydrogen atoms had surely already decayed to ground state. These were likely the first ground state anti-atoms ever made." Since almost all precision measurements require atoms in the ground state, ALPHA's achievement opens a path to new experiments with antimatter.

A principal component of ALPHA's atom trap is a superconducting octupole magnet proposed and prototyped in Berkeley Lab's AFRD. It takes ALPHA about 15 minutes to make and capture atoms of antihydrogen in their magnetic trap.

"So far, the only way we know whether we've caught an anti-atom is to turn off the magnet," says Fajans. "When the anti-atom hits the wall of the trap it annihilates, which tells us that we got one. In the beginning we were turning off our trap as soon as possible after each attempt to make anti-atoms, so as not to miss any."

Says Wurtele, "At first we needed to demonstrate that we could trap antihydrogen. Once we proved that, we started optimizing the system and made rapid progress, a real qualitative change."

Initially ALPHA caught only about one anti-atom in every 10 tries, but Fajans notes that at its best the ALPHA apparatus trapped one anti-atom with nearly every attempt.

Although the physical set-ups are different, ALPHA's ability to hold anti-atoms in a magnetic trap for 1,000 seconds, and presumably longer, compares well to the length of time ordinary atoms can be magnetically confined.

"A thousand seconds is more than enough time to perform measurements on a confined anti-atom," says Fajans. "For instance, it's enough time for the anti-atoms to interact with laser beams or microwaves." He jokes that, at CERN, "it's even enough time to go for coffee."

The ALPHA Collaboration not only made and stored the long-lived antihydrogen atoms, it was able to measure their energy distribution.



"It may not sound exciting, but it's the first experiment done on trapped antihydrogen atoms," Wurtele says. "This summer we're planning more experiments, with microwaves. Hopefully we will measure microwave-induced changes of the atomic state of the anti-atoms." With these and other experiments the ALPHA Collaboration aims to determine the properties of antihydrogen and measure matter-antimatter asymmetry with precision.

A program of upgrades is being planned that will allow experiments not possible with the current ALPHA apparatus. At present the experimenters don't have laser access to the trap. Lasers are essential for performing spectroscopy and for "cooling" the antihydrogen atoms (reducing their energy and slowing them down) to perform other experiments.

Fajans says, "We hope to have laser access by 2012. We're clearly ready to move to the next level."

Thursday, November 25, 2010

Early Universe Was a Liquid, Nuclei Collisions at the Large Hadron Collider Show


In an experiment to collide lead nuclei together at CERN's Large Hadron Collider physicists from the ALICE detector team including researchers from the University of Birmingham have discovered that the very early Universe was not only very hot and dense but behaved like a hot liquid.
Another Real lead-lead collision in ALICE inner 
detector. (Credit: CERN)

By accelerating and smashing together lead nuclei at the highest possible energies, the ALICE experiment has generated incredibly hot and dense sub-atomic fireballs, recreating the conditions that existed in the first few microseconds after the Big Bang. Scientists claim that these mini big bangs create temperatures of over ten trillion degrees.

At these temperatures normal matter is expected to melt into an exotic, primordial 'soup' known as quark-gluon plasma. These first results from lead collisions have already ruled out a number of theoretical physics models, including ones predicting that the quark-gluon plasma created at these energies would behave like a gas.

Although previous research in the USA at lower energies, indicated that the hot fire balls produced in nuclei collisions behaved like a liquid, many expected the quark-gluon plasma to behave like a gas at these much higher energies.

Scientists from the University of Birmingham's School of Physics and Astronomy are playing a key role in this new phase of the LHC's programme which comes after seven months of successfully colliding protons at high energies. Dr David Evans, from the University of Birmingham's School of Physics and Astronomy, and UK lead investigator at ALICE experiment, said: "Although it is very early days we are already learning more about the early Universe."

He continues: "These first results would seem to suggest that the Universe would have behaved like a super-hot liquid immediately after the Big Bang."

The team has also discovered that more sub-atomic particles are produced in these head-on collisions than some theoretical models previously suggested. The fireballs resulting from the collision only lasts a short time, but when the 'soup' cools down, the researchers are able to see thousands of particles radiating out from the fireball. It is in this debris that they are able to draw conclusions about the soup's behaviour.

Two papers detailing this research have been submitted for publication and posted on: http://xxx.lanl.gov/abs/1011.3914| and http://xxx.lanl.gov/abs/1011.3916|.

This research is funded by the Science and Technology Facilities Council (STFC).

Tuesday, July 27, 2010

Largest Particle Accelerator 'Rediscovers' Fundamental Subatomic Particles


The world's largest particle accelerator -- Europe's Large Hadron Collider (LHC) -- has yielded its first measurements of fundamental subatomic particles, so far confirming physicists' Standard Model but also paving the way to future discoveries that may offer new insights into the forces that govern the universe.
Particle tracks fly out from the heart of the ALICE experiment from one of the first collisions at a total energy of 7 TeV. (Credit: Copyright CERN)

First results from the LHC at CERN are being revealed at the International Conference on High Energy Physics (ICHEP), the world's largest international conference on particle physics, which has attracted more than 1000 participants to its venue in Paris. The spokespersons of the four major experiments at the LHC -- ALICE, ATLAS, CMS and LHCb -- are presenting measurements from the first three months of successful LHC operation at 3.5 TeV per beam, an energy three and a half times higher than previously achieved at a particle accelerator.

With these first measurements the experiments are rediscovering the particles that lie at the heart of the Standard Model -- the package that contains current understanding of the particles of matter and the forces that act between them. This is an essential step before moving on to make discoveries. Among the billions of collisions already recorded are some that contain 'candidates' for the top quark, for the first time at a European laboratory.

"Rediscovering our 'old friends' in the particle world shows that the LHC experiments are well prepared to enter new territory," said CERN's Director-General Rolf Heuer. "It seems that the Standard Model is working as expected. Now it is down to nature to show us what is new."

The quality of the results presented at ICHEP bears witness both to the excellent performance of the LHC and to the high quality of the data in the experiments. The LHC, which is still in its early days, is making steady progress towards its ultimate operating conditions. The luminosity -- a measure of the collision rate -- has already risen by a factor of more than a thousand since the end of March. This rapid progress with commissioning the LHC beam has been matched by the speed with which the data on billions of collisions have been processed by the Worldwide LHC Computing Grid, which allows data from the experiments to be analysed at collaborating centres around the world.

"Within days we were finding Ws, and later Zs -- the two carriers of the weak force discovered here at CERN nearly 30 years ago," said Fabiola Gianotti, spokesperson for the 3000-strong ATLAS collaboration. "Thanks to the efforts of the whole collaboration, in particular the young scientists, everything from data-taking at the detector, through calibration, data processing and distribution, to the physics analysis, has worked fast and efficiently."

"It is amazing to see how quickly we have 're-discovered' the known particles: from the lightest resonances up to the massive top quark. What we have shown here in Paris is just the first outcome of an intense campaign of accurate measurements of their properties." said Guido Tonelli, spokesperson for CMS. "This patient and systematic work is needed to establish the known background to any new signal."

"The LHCb experiment is tailor-made to study the family of b particles, containing beauty quarks," said the experiment's spokesperson Andrei Golutvin, "So it's extremely gratifying that we are already finding hundreds of examples of these particles, clearly pin-pointed through the analysis of many particle tracks."

"The current running with proton collisions has allowed us to connect with results from other experiments at lower energies, test and improve the extrapolations made for the LHC, and prepare the ground for the heavy-ion runs," said Jurgen Schukraft, spokesperson for the ALICE collaboration. This experiment is optimized to study collisions of lead ions, which will occur in the LHC for the first time later this year.

Two further experiments have also already benefited from the first months of LHC operation at 3.5 TeV per beam. LHCf, which is studying the production of neutral particles in proton-proton collisions to help in understanding cosmic-ray interactions in the Earth's atmosphere, has already collected the data it needs at a beam energy of 3.5 TeV. TOTEM, which has to move close to the beams for its in-depth studies of the proton, is beginning to make its first measurements.

CERN will run the LHC for 18-24 months with the objective of delivering enough data to the experiments to make significant advances across a wide range of physics processes. With the amount of data expected, referred to as one inverse femtobarn, the experiments should be well placed to make inroads in to new territory, with the possibility of significant discoveries.

Wednesday, March 31, 2010

Large Hadron Collider: Beams Colliding at Record Energies Mark Start of Research Program


Beams collided at 7 trillion (1012) electron volts (or 7 tera electron volts -- TeV) in the Large Hadron Collider on March 30 at 13:06 Central European Summer Time (CEST) at CERN, marking the start of the LHC research programme. Particle physicists around the world are looking forward to a potentially rich harvest of new physics as the LHC begins its first long run at an energy three and a half times higher than previously achieved at a particle accelerator.
Large Hadron Collider
An event at the Large Hadron Collider beauty experiment (LHCb), which physicists are carrying out for precise measurements of CP violation and rare decays. (Credit: Copyright CERN)
"It's a great day to be a particle physicist," said CERN Director General Rolf Heuer. "A lot of people have waited a long time for this moment, but their patience and dedication is starting to pay dividends."

"With these record-shattering collision energies, the LHC experiments are propelled into a vast region to explore, and the hunt begins for dark matter, new forces, new dimensions and the Higgs boson," said ATLAS collaboration spokesperson, Fabiola Gianotti. "The fact that the experiments have published papers already on the basis of last year's data bodes very well for this first physics run."

"We've all been impressed with the way the LHC has performed so far," said Guido Tonelli, spokesperson of the CMS experiment, "and it's particularly gratifying to see how well our particle detectors are working while our physics teams worldwide are already analysing data. We'll address soon some of the major puzzles of modern physics like the origin of mass, the grand unification of forces and the presence of abundant dark matter in the universe. I expect very exciting times in front of us."

"This is the moment we have been waiting and preparing for," said ALICE spokesperson Jürgen Schukraft. "We're very much looking forward to the results from proton collisions, and later this year from lead-ion collisions, to give us new insights into the nature of the strong interaction and the evolution of matter in the early Universe."

"LHCb is ready for physics," said the experiment's spokesperson Andrei Golutvin, "we have a great research programme ahead of us exploring the nature of matter-antimatter asymmetry more profoundly than has ever been done before."

CERN will run the LHC for 18-24 months with the objective of delivering enough data to the experiments to make significant advances across a wide range of physics channels. As soon as they have "re-discovered" the known Standard Model particles, a necessary precursor to looking for new physics, the LHC experiments will start the systematic search for the Higgs boson. With the amount of data expected, called one inverse femtobarn by physicists, the combined analysis of ATLAS and CMS will be able to explore a wide mass range, and there's even a chance of discovery if the Higgs has a mass near 160 GeV. If it's much lighter or very heavy, it will be harder to find in this first LHC run.

For supersymmetry, ATLAS and CMS will each have enough data to double today's sensitivity to certain new discoveries. Experiments today are sensitive to some supersymmetric particles with masses up to 400 GeV. An inverse femtobarn at the LHC pushes the discovery range up to 800 GeV.

"The LHC has a real chance over the next two years of discovering supersymmetric particles," explained Heuer, "and possibly giving insights into the composition of about a quarter of the Universe."

Even at the more exotic end of the LHC's potential discovery spectrum, this LHC run will extend the current reach by a factor of two. LHC experiments will be sensitive to new massive particles indicating the presence of extra dimensions up to masses of 2 TeV, where today's reach is around 1 TeV.

"Over 2000 graduate students are eagerly awaiting data from the LHC experiments," said Heuer. "They're a privileged bunch, set to produce the first theses at the new high-energy frontier."

Following this run, the LHC will shutdown for routine maintenance, and to complete the repairs and consolidation work needed to reach the LHC's design energy of 14 TeV following the incident of 19 September 2008. Traditionally, CERN has operated its accelerators on an annual cycle, running for seven to eight months with a four to five month shutdown each year. Being a cryogenic machine operating at very low temperature, the LHC takes about a month to bring up to room temperature and another month to cool down. A four-month shutdown as part of an annual cycle no longer makes sense for such a machine, so CERN has decided to move to a longer cycle with longer periods of operation accompanied by longer shutdown periods when needed.

"Two years of continuous running is a tall order both for the LHC operators and the experiments, but it will be well worth the effort," said Heuer. "By starting with a long run and concentrating preparations for 14 TeV collisions into a single shutdown, we're increasing the overall running time over the next three years, making up for lost time and giving the experiments the chance to make their mark."
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Thursday, January 7, 2010

The Large Hadron Collider : Physicists Beginning to See Data


Three Iowa State University physicists who took winter trips to the Large Hadron Collider for meetings and experimental work are starting to see real data from the planet's biggest science experiment.

Last month the ATLAS experiment at the Large Hadron Collider began recording proton-proton collisions at a record energy of 2.36 trillion electron volts. Image courtesy of the ATLAS experiment. (Credit: Image courtesy of Iowa State University)

Finally.

The multibillion-dollar collider made international news on Sept. 10, 2008, when it sent its first beam of protons around 17 miles of underground tunnel near Geneva, Switzerland. But breakdowns in the machine's high-current electrical connections forced a complete shutdown for more than a year of repairs and tests.

Sunday, March 15, 2009

Physicists closer to finding 'God Particle'



Physicists have come closer to finding the elusive "God Particle," which they hope could one day explain why particles have mass, the US Department of Fermi National Accelerator Laboratory announced. Researchers at the Fermilab have managed to shrink the territory where the elusive Higgs Boson particle is expected to be found - a discovery placing the American research institute ahead of its European rival in the race to discover one of the biggest prizes in physics.

Physicists have long puzzled over how particles acquire mass. In 1964, a British physicist, Peter Higgs, came up with this idea: there must exist a background field that would act rather like treacle. Particles passing through it would acquire mass by being dragged through a mediator, which theoreticians dubbed the Higgs Boson.

The standard quip about the Higgs is that it is the "God Particle" - it is everywhere but remains frustratingly elusive. Confirming the Higgs would fill a huge gap in the so-called Standard Model, the theory that summarizes our present knowledge of particles. Over the years, scientists have whittled down the ranges of mass that the Higgs is likely to have.

Physicists were hopeful that the particle could be found with Europe's Big Bang atom-smasher, the Large Hadron Collider. But the Collider was shut down just days after it was turned on in September 2008 at the European Organisation for Nuclear Research (CERN) below the Franco-Swiss border.

It is not scheduled to be turned back on until September of this year, while researchers at the rival Fermilab have cranked up their efforts to discover the Higgs. Researchers at CERN had already determined that the Higgs must weigh more than 114 GeV/c2, Femilab said in a press release.

Calculations of quantum effects involving the Higgs Boson require its mass to be less than 185 GeV/c2. Using Fermilab's Tevatron collider, researchers were able to "carve out a section in the middle of this range and establish that it cannot have a mass in between 160 and 170 GeV/c2."

They did this by combing the efforts of two major research groups that have analyzed three inverse femtobarns of collision data -- the scientific unit that scientists use to count the number of collisions. Each experiment expects to receive a total of about 10 inverse femtobarns by the end of 2010.

"A particle collision at the Tevatron collider can produce a Higgs boson in many different ways, and the Higgs particle can then decay into various particles," said Fermilab researcher Rob Roser. "Each experiment examines more and more possibilities. Combining all of them, we hope to see a first hint of the Higgs particle."


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