Tag Archives: Large Hadron Collider

Three-decade quest backs physics’ ‘Standard Model’


Meanwhile, religious lunatics, Muslims of course, are beheading people because they belong to the wrong brand of Islam, as well as westerners for being infidels…

The two extremes of mankind’s intellect at work; on the one hand you have science (civilized and rational) and on the other you have religion (barbaric and irrational). Any guess as to which one will be the downfall of man? The answer is clear, and has been for the last 5000 years. TGO

Refer to story below. Source: Associated Press

AFP
A scientist looks at a section of the European Organisation for Nuclear Research (CERN) Large Hadron Collider (LHC) in Meyrin, near Geneva, during maintenance works on July 19, 2013

Paris (AFP) – Scientists on Wednesday said that after a nearly three-decade bid they had detected a telltale change in a sub-atomic particle, further backing a key theory about the Universe.

Researchers at the world’s biggest particle collider said they had observed an extremely rare event — the decay of the neutral B meson into a pair of muons, the heavy cousins of electrons.

The results provide further support for the so-called Standard Model, the conceptual framework for the particles and forces that constitute the cosmos, they said in the journal Nature.

Neutral B mesons are unstable composites of two kinds of particles called quarks, bound by the “strong” force.

Their decay into muons is predicted under the Standard Model. But getting evidence to confirm the prediction has been a puzzler since the mid-1980s.

For one thing, neutral B mesons themselves are produced in extreme conditions — in particle colliders or in cosmic-ray interactions, for instance — which makes them hard or very costly to study.

And the transition into muons only occurs about four times in every billion “decays.”

Rival teams at CERN’s Large Hadron Collider (LHC) — the massive underground lab near Geneva that straddles the Franco-Swiss border — worked separately on detecting the elusive event.

They released individual results in July 2013, but, separately, the data batches fell just short of the demanding threshold of accuracy for claiming a discovery.

Their combined analysis, now published in the benchmark peer-reviewed science journal, “easily exceeds this requirement,” the European Organisation for Nuclear Research (CERN) said in a statement.

The paper said the experiments showed that Standard Model, which dates to the 1970s, had cleared another hurdle but others lay ahead.

“In the course of the past few decades, the Standard Model has passed critical tests derived from experiment, but it does not address some profound questions about the nature of the Universe,” the authors said.

The framework does not, for instance, explain dark matter, the stuff that composes nearly 85 percent of the mass in the cosmos and is currently only detectable through its gravitational effect on visible matter.

The quest to understand dark matter is one of the priorities of the current work programme at the LHC, which began last month after a two-year upgrade.

The collider comprises a ring-shaped tunnel where proton beams are whizzed around in opposite directions at speeds approaching that of light.

At four locations in the tunnel, powerful magnets bend the beams, bringing them together so that some of the protons smash together — a brief, intense collision.

The sub-atomic rubble that results is then analysed to look for novel particles or clues about known ones.

In 2012, the LHC confirmed the Higgs Boson, the long-sought Standard Model particle that confers mass.

It earned the 2013 Nobel physics prize for two of the scientists who back in 1964 had theorised the boson’s existence.

CERN’s revamped particle smasher ready to push physics into unknown


Where would we be as a species if it wasn’t for science? We would still be living in caves and hunting for food with primitive tools, much as our ancestors did tens of thousands of years ago. Yet here we are, trying to unlock the mysteries of the universe. TGO

Refer to story below. Source: Associated Press

AFP

The Globe of Science and Innovation at the European Organisation for Nuclear Research (CERN) in Meyrin, near Geneva, Switzerland, on February 10, 2015
 

Geneva (AFP) – Europe’s physics lab CERN said Thursday it had begun tests in preparation for rebooting the world’s biggest particle collider and trying to uncover new particles that could alter our understanding of the Universe.

“We are really excited, because we are entering a new phase,” CERN director general Rolf Heuer told reporters in Geneva.

CERN’s Large Hadron Collider (LHC) went offline in February 2013 for a massive overhaul after identifying what is believed to be the Higgs boson, the long-sought maker of mass theorised in the 1960s.

The giant lab, housed in a 27-kilometre (17-mile) tunnel straddling the French-Swiss border, flushed out the so-called “God particle” by crashing proton beams at velocities near the speed of light.

Now, after nearly doubling energy levels possible in the collider, CERN scientists have their sights set on finding exotic new particles in a previously-inaccessible realm.

Frederick Bordry, CERN director for accelerators and technology, said that proton beams were injected into the LHC over the weekend, especially to test transfer lines.

“It was a good test,” he said.

CERN now plans to begin rebooting the machine within the next two week, allowing beams containing billions of protons travelling at 99.9 percent the speed of light to shoot through the massive ring-shaped collider.

LHC

By the end of May, the mighty machine should be calibrated to reach energy levels allowing the long-awaited proton collisions — brief but super-intense smashups recorded in four labs dotted around the ring — to begin.

The collider’s previous highest power was 8 TeV reached in 2012, but after the upgrade, it will first reach 13 TeV and can potentially be cranked up to a maximum 14 TeV.

– Cracks in Standard Model? –

Firing up the LHC is not like throwing a light switch, Heuer said, stressing the delicacy of the process and pointing out that the two beams that will be shooting around the loop together will have the power to melt a tonne of copper.

“We don’t want to do that. So we are better off increasing the intensity and the power of the beams step by step,” he said.

Experiments at the collider have been seeking to unlock clues as to how the Universe came into existence by studying fundamental particles, the building blocks of all matter, and the forces that control them.

During its next run, researchers will look for evidence of “new physics”. They will probe ‘supersymmetry’ — a theoretical concept informally dubbed Susy — seek explanations for enigmatic dark matter, and look for signs of extra dimensions.

Ordinary, visible matter comprises only about four percent of the known Universe.

“There is an enormous amount of speculation out there that we could go beyond the standard model,” said Tiziano Camporesi, head of the LHC’s Compact Muon Solenoid (CMS) experiment, referring to the mainstream theory of how our visible Universe is constructed.

“We have to prepare our detectors in order to be ready to also look for the unexpected, so we can see whatever may exceed the standard model as we know it,” he said, insisting that the LHC was “at the frontier of what can be done in our field.”

He acknowledged that it was difficult to say when the unexpected might appear.

“If nature is kind with us, it could be quick, and if less kind, it could take some time,” Camporesi said.

While the timeline remains unclear, Heuer meanwhile said he was sure the LHC had new discoveries in store.

“It is high time to find a crack in the standard model,” he said, pointing out that “there is 95 percent of the universe that is still unknown to us.”

Particle physics: Experiments give shape to Higgs


Interesting stuff… TGO

Refer to story below. Source: Associated Press

AFP

Physicists

Paris (AFP) – Physicists on Sunday said they had learned more about the identity of the Higgs Boson, the elusive particle whose ground-breaking discovery was announced nearly two years ago.

Work at the Large Hadron Collider (LHC) — the particle smasher on the French-Swiss border where the breakthrough was made — has answered long-standing questions about how the Higgs behaves, they said.

The Higgs was theorised in the 1960s as being the sub-atomic particle that gives other particles mass. Without it, matter would not exist.

Decades of work followed to explore the idea until on July 4, 2012, rival teams at the LHC announced they had independently found a particle consistent with the Higgs.

But further work was needed to flesh out this discovery and to see how it fits with the Standard Model, the conceptual framework for explaining visible matter in the Universe.

In a study published in the journal Nature Physics, one of the LHC teams said the boson behaves as predicted, and is not an “imposter that looks like it.”

Analysis of the mountain of data from collisions at the LHC shows the boson decays neatly to a group of sub-particles called fermions, in line with Standard Model theory, the paper said.

“This is an enormous breakthrough,” said Markus Klute of the Massachusetts Institute of Technology (MIT) who led the research at the LHC’s Compact Muon Solenoid (CMS).

“Now we know that particles like electrons get their mass by coupling to the Higgs field, which is really exciting.”

Finding the Higgs was only possible through the building of the LHC, the world’s biggest laboratory, made up of a 27-kilometre (17-mile) ring-shaped tunnel.

An army of physicists from around the world sifted through the rubble left from billions of proton smashups, hunting for a telltale signature from a fleeting particle.

The initial discovery put the Higgs’ mass at between 125 to 126 gigaelectronvolts, a standard unit of measurement at sub-atomic level.

Later analysis of the data from these experiments also found that the boson has no “spin,” and rapidly decays into pairs of photons (particles of light) and so-called W or Z bosons.

“We have now established the main characteristics of this new particle,” said Klute in a press release issued by MIT.

“All of these things are consistent with the Standard Model.”

Experiments at the LHC are currently on hold while the collider goes through an upgrade, although scientists are still trawling through reams of data generated from smashups before the shutdown.

Operations are due to resume in 2015, with a three-year programme that will see scientists use more powerful collisions to explore theorised phenomena such as “super-symmetry” which may explain dark matter, the substance that makes up most of the Universe.

The boson is named after Peter Higgs, a British physicist who co-won the Nobel prize last year with Francois Englert of Belgium.

Other physicists who made big contributions were Robert Brout, also a Belgian, who died in 2011, and a US-British team of Dick Hagen, Gerald Guralnik and Tom Kibble.

Elusive ‘Exotic Hadron’ Particles Confirmed


Interesting stuff… TGO

Refer to story below. Source: LiveScience

LHC

The existence of exotic hadrons — a type of matter that doesn’t fit within the traditional model of particle physics — has now been confirmed, scientists say.

Hadrons are subatomic particles made up of quarks and antiquarks (which have the same mass as their quark counterparts, but opposite charge), which interact via the “strong force” that binds protons together inside the nuclei of atoms.

Researchers working on the Large Hadron Collider beauty (LHCb) collaboration at CERN (the European Organization for Nuclear Research) in Switzerland — where the elusive Higgs boson particle was discovered in 2012 — announced today (April 14) they had confirmed the existence of a new type of hadron, with an unprecedented degree of statistical certainty.

“We’ve confirmed the unambiguous observation of a very exotic state — something that looks like a particle composed of two quarks and two antiquarks,” study co-leader Tomasz Skwarnicki, a high-energy physicist at Syracuse University in New York said in a statement. The discovery “may give us a new way of looking at strong-[force] interaction physics,” he added.

The Standard Model of particle physics allows for two kinds of hadrons. “Baryons” (such as protons) are made up of three quarks, and “mesons” are made up of a quark- antiquark pair. But since the Standard Model was developed, physicists have predicted the existence of other types of hadrons composed of different combinations of quarks and antiquarks, which could arise from the decay of mesons.

In 2007, a team of scientists called the Belle Collaboration that was using a particle accelerator in Japan discovered evidence of an exotic particle called Z(4430), which appeared to be composed of two quarks and two antiquarks. But some scientists thought their analysis was “naïve” and lacked good evidence, Skwarnicki said.

A few years later, a team known as BaBar used a more sophisticated analysis that seemed to explain the data without exotic hadrons.

“BaBar didn’t prove that Belle’s measurements and data interpretations were wrong,” Skwarnicki said. “They just felt that, based on their data, there was no need to postulate existence of this particle.”

So the original team conducted an even more rigorous analysis of the data, and found strong evidence for the particle.

Now, the LHCb team has studied data from more than 25,000 meson decay events selected from data from 180 trillion proton-proton collisions in the Large Hadron Collider, the world’s largest and most powerful particle accelerator. They analyzed the data using both the Belle and BaBar teams’ methods, and confirmed the particle was both real and an exotic hadron.

The results of the experiment are “the clincher” that such particles do exist, and aren’t just some artifact of the data, Skwarnicki said.

His colleague, Sheldon Stone of CERN, also praised the achievement. “It’s great to finally prove the existence of something that we had long thought was out there,” he said.

Follow Tanya Lewis on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science.

Story of the Biggest Experiment in History Caught on Film


Interesting stuff… TGO

Refer to story below. Source: LiveScience

LiveScience.com By Tanya Lewis, Staff Writer 

LHC

On July 4, 2012, scientists around the world waited with bated breath for the announcement that the long-awaited Higgs boson particle had been discovered. The finding — the result of the biggest and most expensive experiment in history — was set to either confirm reigning models of particle physics, or reveal gaps in scientists’ understanding of the universe.

A new documentary follows six scientists during the launch of the machine that made the discovery possible, the Large Hadron Collider (LHC), a gigantic particle accelerator at the European Organization for Nuclear Research (CERN), in Switzerland, as they attempt to recreate the earliest moments of the universe. “Particle Fever” captures the scientists’ sense of excitement and foreboding leading up to the discovery of the Higgs, the particle that explains how other particles get their mass.

“I knew this big event was coming, and I wanted it recorded,” said producer David Kaplan, a physicist at Johns Hopkins University in Baltimore, Md. “I knew it was going to be extremely dramatic scientifically, and also emotionally, for all of my colleagues,” Kaplan told Live Science.

The film, which opens March 5 in New York and March 21 in Washington, D.C., stars a group of theoretical and experimental physicists united by a quest to probe the nature of the universe, using the world’s most powerful particle accelerator. The LHC collides two beams of protons (particles that make up the nuclei of atoms) at near light-speed around the 17 miles (27 kilometers) of the machine’s ring. The collisions produce new particles, which could reveal the composition of space itself.

The film opens during the first test of a single proton beam in September 2008. Viewers meet Fabiola Gianotti, the former spokeswoman for ATLAS, one of the two LHC experiments that detected the Higgs, as well as experimental physicists Monica Dunford and Martin Aleksa, both at ATLAS, who rose to prominence throughout the course of the experiment. Mike Lamont, the LHC’s beam operation leader, also features in the film. Lamont faces the formidable challenge of ensuring the LHC’s successful launch and operation.

But to understand why scientists need the LHC, one first has to understand the hypotheses it is putting to the test.

Supersymmetry vs. multiverse

The Standard Model of particle physics, finalized in the 1970s, seeks to explain the origin of matter and forces in the universe. The model predicts the existence of a few fundamental particles, including the Higgs boson, theorized by British physicist Peter Higgs in 1964. Finding the Higgs confirms the existence of the Higgs field, and this field gives all other particles their mass.

An extension of the Standard Model known as supersymmetry suggests a highly structured and symmetrical universe, in which every particle has a supersymmetric twin that has yet to be discovered. Another, somewhat radical hypothesis suggests the known universe is part of a much larger, chaotic multiverse, in which the laws of physics are random.

The film pits Kaplan and Stanford theorist Savas Dimopoulos, proponents of supersymmetry, against the young Princeton theorist Nima Arkani-Hamed, a supporter of the multiverse idea. The LHC offers the chance to test these hypotheses for the first time. If supersymmetry proves itself, physicists are on the right track. On the other hand, “We may fall off a cliff,” and find that the fundamental laws of physics turn out to be random, Kaplan said.

Biggest experiment in history

The beam test went off successfully in 2008, but a few weeks later, a catastrophic explosion in the facility vented liquid helium, damaging many of the magnets inside the LHC.

“The whole film changed,” said director Mark Levinson, who added he didn’t know how long it would take to fix the damage, and whether the film would have a happy ending. Fortunately, repairs were completed, and the collider was up and running by November 2009.

Fast-forward to July 2012, and the discovery of the Higgs. The particle observed by the LHC confirmed what physicists had long suspected, but also brought up new questions.

Most supersymmetry models predict a Higgs boson with a mass of about 115 gigaelectronvolts, or GeV, whereas multiverse models predict a heavier mass of about 140 GeV. The Higgs observed by the LHC was about 125 GeV — smack in the middle, which doesn’t confirm or rule out either theory. Instead, it merely narrows down the possibilities.

It’s like being lost in the woods, and then getting a hint of the broad direction you should go, Kaplan said, adding, “At least you know which way to start walking.”

In the next step, scientists will collide protons at higher energies, to see if even more particles are created, as predicted by supersymmetry. The LHC was shut down for upgrades in 2013, with plans to reopen it running at twice the power in 2015.

The filmmakers hope “Particle Fever” gives audiences an appreciation of particle physics, and gets them excited about learning more. As Kaplan said, “We want people to come out thinking physics is awesome.”

Editor’s Note: This article was updated at 6:07 p.m. ET, to correct references to untested “theories” to “hypotheses” or “models.”

Follow Tanya Lewis on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science.

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