CERN releases analysis of LHC incident

October 16, 2008 | 11:21 am

Investigations have shown that a faulty electrical connection between two magnets (shown in red) was the cause of the incident in sector 3-4 of the LHC on 19 September.

From a CERN press release

Geneva, 16 October 2008–Investigations at CERN following a large helium leak into sector 3-4 of the Large Hadron Collider (LHC) tunnel have confirmed that cause of the incident was a faulty electrical connection between two of the accelerator’s magnets. This resulted in mechanical damage and release of helium from the magnet cold mass into the tunnel.

Proper safety procedures were in force, the safety systems performed as expected, and no one was put at risk. Sufficient spare components are in hand to ensure that the LHC is able to restart in 2009, and measures to prevent a similar incident in the future are being put in place.

“This incident was unforeseen,” said CERN Director General Robert Aymar, “but I am now confident that we can make the necessary repairs, ensure that a similar incident can not happen in the future and move forward to achieving our research objectives.”

The summary report follows:

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Stanford Linear Accelerator Center renamed SLAC National Accelerator Laboratory

October 15, 2008 | 2:45 pm

New SLAC National Accelerator Laboratory logo

New Name Honors Successful Past, Launches a Future of Scientific Expansion

The US Department of Energy (DOE) has renamed Stanford Linear Accelerator Center the SLAC National Accelerator Laboratory.

What’s in a name? Great past, great future, great science. . . .

“The new laboratory name acknowledges the distinguished accomplishments SLAC has achieved over the years, and its exciting future as a multi-program Department of Energy National Laboratory,” said Under Secretary for Science Dr. Raymond L. Orbach. “The Laboratory’s world-leading set of core capabilities makes it a key member of the Department’s National Laboratory complex, and fuels the Office of Science research capabilities for the future.”

In recent years, SLAC’s research program has broadened from its original focus on high-energy physics to include strong photon science and particle astrophysics programs. The lab’s current science programs are expanding to explore the ultimate structure and dynamics of matter and the properties of energy, space and time at the smallest and largest scales. This includes the study of ultra-fast processes in materials with a new state-of-the-art X-ray free electron laser, the Linac Coherent Light Source (LCLS).

“Stanford University is extremely excited with the future of discovery that SLAC National Accelerator Laboratory will enable,” said Stanford University President John Hennessy. “Its broadening scientific portfolio builds upon our core competencies, and the new name signifies the continued strength of our DOE collaboration.”

Laboratory Director Persis Drell said, “Our new name, SLAC National Accelerator Laboratory, is a strong bridge that connects our successful past with our tremendously exciting future. We look forward to keeping this laboratory at the forefront of innovating, building and operating accelerator-based facilities as a Department of Energy National Accelerator Laboratory.”

SLAC National Accelerator Lab’s multi-purpose mission covers a wide range of science. The upcoming startup of the LCLS-planned for 2009-along with the existing SPEAR3 synchrotron X-ray light source, will position the lab as a world-leader in X-ray science. Using these facilities as microscopes on the nanoworld, the lab’s scientists and the national-user communities are working out the structures of proteins and characterizing the quantum workings of new materials. The ability to make the first stop-motion movies of atoms and molecules in action with the LCLS will open new frontiers of research in materials, chemistry, and biology.

The lab’s programs in particle astrophysics, such as the recently launched Fermi Gamma-ray Space Telescope, and the planned Large Synoptic Survey Telescope, are allowing us to see how the universe has evolved, and will provide a key to understanding the mysteries of dark matter and energy.

In addition, DOE’s SLAC National Accelerator Lab will continue to participate in accelerator-based particle physics experiments such as the ATLAS experiment at the Large Hadron Collider.

SLAC National Accelerator Laboratory is operated by Stanford University for the US Department of Energy. The laboratory’s mission is to explore the frontiers of photon science, astrophysics, and accelerator and particle physics in service to the nation and the world.

See the animated SLAC National Accelerator Laboratory logo.

Text from a SLAC National Accelerator Laboratory press release.

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Crunch time for Joint Dark Energy Mission

October 14, 2008 | 7:30 am

Last month’s surprise cancellation of the competition to develop the Joint Dark Energy Mission left researchers stunned.  Now the former competitors have less than two months to come together and redefine what the mission should accomplish–a mission that will be developed and overseen not by a single, winning team but by JDEM’s government sponsors, NASA and the US Department of Energy.

The two agencies have appointed a committee that meets for the first time on Wednesday in Washington, DC.  Called the Science Coordination Group, it includes representatives of each of the formerly competing teams and has the delicate task of determining broad science goals and observational requirements for the mission’s new incarnation. They must include observations of at least three types of phenomena–supernovae, weak gravitational lensing, and baryon acoustic oscillation.

The group will also contribute to the design of an initial Reference Mission, to be delivered by the end of 2008. At that point the agencies will call for proposals for science investigations, with science teams to be selected next year.

“They’ve hit the reset button. It’s a start anew,” Michael Levi of Lawrence Berkeley National Laboratory told me. The Science Coordination Group “has six weeks to come up with a new mission, to take several lumps of clay and mush them together.”

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Glennda Chui

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Oak Ridge opens "big bang beamline" to probe the neutron

October 13, 2008 | 12:05 pm

The Spallation Neutron Source at Oak Ridge National Laboratory in Tennessee has opened a neutron beamline dedicated to the study of the neutron itself.  This close neighbor of the proton may hold clues to the nature of the early universe, matter’s triumph over antimatter and other compelling questions; the new  Fundamental Neutron Physics Beamline is dedicated to digging them out.

An article in Physics World neatly sums it up:

Neutrons are, of course, neutral. But the FNBP will be able to examine whether, for example, the charged quarks inside neutrons give the particle a slight dipole. Such a dipole could help explain why the universe is almost solely made from matter and not antimatter. The FNBP will also look into the decay of free neutrons — which bound in nuclei are normally quite stable — to clarify the distribution of elements shortly after the Big Bang. Finally, the the FNBP will measure the interactions between neutrons and nuclei, hopefully to shed light on so-called symmetry violation — a concept that was first outlined theoretically by Yoichiro Nambu, joint winner of this year’s Nobel Prize for Physics.

And from the Oak Ridge press release:

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Glennda Chui

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Springer Publishing to acquire BioMedCentral

October 9, 2008 | 6:04 am

“Springer to acquire BioMedCentral.” Those of us in physics may well wonder what this headline has to do with us. “BioMed” is not usually associated with high-energy physics (HEP), and Springer is, to most physicists, a big publisher that we occasionally deal with when submitting to Eur.Phys.J. or similar journals.

However, it is worth remembering that BioMedCentral (BMC) has a physics journal as well. The recently launched PhysMathCentral (an arm of BMC) journal PMC Physics A is an exciting new Open Access journal in HEP, so the sale does affect physics literature. I certainly hope that PhysMathCentral will continue to be a leading Open Access journal in the field, paving the way for broader Open Access in the future of HEP publishing. BMC has, since its founding in 2000, been a leader in Open Access, becoming the world’s first for-profit Open Access publisher and the world’s largest Open Access publisher of any kind. In light of this, Springer’s acquisition carries with it some interesting questions.

Will Springer begin to adopt BMC’s commitment to Open Access?

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Travis Brooks

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Brookhaven National Lab and the 2008 Nobel Prize in Physics

October 8, 2008 | 12:43 pm

Yesterday we reported on the 2008 Nobel Prize in Physics. Here is an article that connects Tuesday’s Nobel Prize with the work done at the Department of Energy’s Brookhaven National Laboratory on Long Island, NY. See our other stories for information about SLAC and Fermilab connections to the Nobel Prize.

In the 1950s, interpreting experiments conducted at Brookhaven Lab, physicists T.D. Lee and C.N. Yang (bottom left and bottom right, respectively) discovered that parity was not invariant. In 1964, also at Brookhaven, James Cronin (top left) and Val Fitch (top right)discovered that the decay of K mesons also violated the combined symmetry of C and P, or CP.

One American and two Japanese physicists have won the 2008 Nobel Prize in Physics for their work on symmetry breaking. The prize is shared by Yoichiro Nambu of the University of Chicago, Makoto Kobayashi of the High Energy Accelerator Research Organization (Japan), and Toshihide Maskawa of Kyoto University. Nambu will receive half the prize for this work on the general mechanism of spontaneous symmetry breaking, while Kobayashi and Maskawa are being recognized for their theoretical work that ties symmetry breaking to the existence of three families of quarks.

Symmetry plays an important role in physics. The three new physics laureates studied how symmetries are preserved or violated in various ways. Their work builds in part on earlier theoretical and experimental studies at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory, which also received Nobel recognition in 1957 and 1980.

What is symmetry? The geometrical symmetry of the two sides of the human face is an example of something being the same or equivalent. Rotate a sixfold-symmetric snowflake through one-sixth of a circle and it will look the same.

In physics, symmetry is a more general concept and applies to the idea that a physical situation will be the same even if a certain transformation occurs. Three of the most fundamental symmetries bear the name of time reversal invariance (symbolized by the letter T), charge conjugation invariance (C), and parity invariance (P).

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David Harris

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Fermilab and symmetry breaking

October 8, 2008 | 11:01 am

Yesterday we reported on the 2008 Nobel Prize in Physics. Here is an article that connects Tuesday’s Nobel Prize with the work done at the Department of Energy’s Fermi National Accelerator Laboratory in Batavia, Ill. See this story for information about SLAC’s connection to the Nobel Prize.

Fermilab and symmetry breaking

Yoichiro Nambu, Makoto Kobayashi and Toshihide Maskawa won the 2008 Nobel Prize in Physics for their work on symmetry breaking in the world of elementary particles and forces. The prize recognizes the pioneering development of a picture of nature that has had a major impact on physics at Fermilab and at other laboratories around the world. Nambu’s formulation of symmetry breaking allows physicists to explain why there is matter in the universe, while the work of Kobayashi and Maskawa provides the theoretical tools to explain why the universe contains no antimatter.

When physicists discuss symmetries, they refer to things that appear identical. Symmetry breaking is a way of explaining why things look different from each other. An example is gravity. Skaters have no problem gliding in any direction on an ice rink. But if they jump up, gravity pulls them back down. Gravity breaks the symmetry between left and right motion and up and down motion. Every time you jump up, you rediscover gravity through symmetry breaking.

Yoichiro Nambu incorporated what is known as spontaneous symmetry breaking into the theory of elementary particles to explain why different particles have different masses–why nature allows massive quarks and electrons and massless photons. When Weinberg, Glashow, and Salam earned the Nobel Prize in 1979 for unifying the electromagnetic and weak forces into the electroweak force, they needed to explain why the force carrier of the electromagnetic force, the photon, was massless, while the force carriers of the weak force were very heavy. The concept of spontaneous symmetry breaking allowed them to overcome this difficulty. Without this broken symmetry, matter as we know it would not exist. All particles would be massless and moving at the speed of light.

From the combination of  spontaneous symmetry breaking and electroweak unification comes an exciting prediction: a new particle called the Higgs boson. The Higgs is the hammer that breaks the symmetry and gives different particles different masses.  Currently, close to a thousand physicists from around the world are searching for the Higgs boson in collisions produced by the Tevatron accelerator at Fermilab.

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SLAC and the 2008 Nobel Prize in Physics

October 8, 2008 | 10:18 am

Yesterday we reported on the 2008 Nobel Prize in Physics. Here is an article that connects Tuesday’s Nobel Prize with the work done at the Department of Energy’s Stanford Linear Accelerator Laboratory in California. See this story for information on Fermilab’s connection to the Nobel Prize.

Nobel Prize Recognizes Particle Physicists, Notes Key BaBar Finding

The 2008 Nobel Prize in Physics has been awarded to Yoichiro Nambu “for the discovery of the mechanism of spontaneous broken symmetry in subatomic physics,” and to Makoto Kobayashi and Toshihide Maskawa “for the discovery of the origin of the broken symmetry which predicts the existence of at least three families of quarks in nature.”

The Nobel Foundation’s press release includes explicit mention of SLAC’s BaBar experiment because it helped confirm one of the key predictions by Kobayashi and Maskawa.

BaBar has studied in detail the phenomenon of CP violation, which is partly responsible for the imbalance between matter and antimatter observed in the universe. CP violation had been observed in particles called kaons or K mesons in 1964. However, it wasn’t until Kobayashi and Maskawa developed their theoretical approach in 1972 that the phenomenon could be explained. However, Kobayashi and Maskawa’s approach required a third generation of quarks. Experiments conducted soon after this prediction found evidence of the third generation. (The first generation includes the up and down quarks, the second has the strange and charm, and the third consists of the top and bottom.)

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David Harris

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Removing pesky electrons

October 8, 2008 | 6:28 am

This insert, manufactured by SLAC and the company EMEGA, will be placed inside the KEK-B accelerator beam pipe to trap stray electrons with its triangular grooves. (Photo by Mauro Pivi.)

As accelerators around the world increase in power, clouds become more and more of a problem. These are not thunder clouds sending lightning bolts at power supplies, but rather electron clouds: a haze of electrons that gathers in accelerator beam pipes and disrupts positron or proton beams. Now, researchers from SLAC and KEK are using the positron beam at KEK’s B Factory in Japan to test one promising technique to clear these clouds.

Electron clouds begin to form when a stray electron strikes the interior wall of the beam pipe, producing two electrons. “In turn, those electrons strike the wall, and from two they become 4, then 8, then 16, then 32,” said SLAC researcher Mauro Pivi. “And soon, an electron cloud forms.” The cloud attracts the positively-charged beam traveling through the pipe, causing the beam to behave erratically—not ideal when the end goal is to very accurately collide two particle beams.

An insert without grooves (top) currently sits within the KEK-B accelerator beam pipe. (Photo courtesy of KEK.)

To reduce the electron cloud problem SLAC researchers Pivi and Lanfa Wang, and KEK physicists Yusuke Suetsugu and Hitoshi Fukuma, designed beam pipes with a grooved inner surface. This surface, which from the side looks rather like a row of triangular shark teeth, traps incoming electrons and keeps them—and their resulting cloud of electrons—ricocheting within the well of the groove until they have dissipated enough energy to be absorbed into the beam pipe wall.

This type of triangular groove is currently undergoing tests at KEK-B. Future experiments are planned at the Cornell Electron Storage Ring Test Accelerator and the European accelerator laboratory CERN. At KEK-B, a beam pipe without grooves has been installed into a short region of the accelerator. A detector just behind the pipe will monitor the number of electrons produced over the next two months of operation. Then, technicians will replace the smooth beam pipe with the triangular grooved version. After two additional months of data collection, Pivi and colleagues will compare the number of electrons detected with the smooth and grooved beam pipes.

The region in the KEK-B accelerator where the inserts are being tested. (Photo courtesy of KEK.)

Previous experiments at SLAC’s PEP-II proved that rectangular grooves work well to capture stray electrons in an environment with no magnetic field. Without a magnetic field, the electrons zip into the groove from all directions, and are trapped as they ricochet from side to side. The triangular grooves, Pivi said, should work in the magnetic field that surrounds the KEK-B test region. That’s because in a magnetic field, the electrons spiral straight down into the groove along the field lines. Inside the groove, they collide with the sloped walls and become trapped, instead of simply bouncing off the flat bottom of a rectangular groove and spiraling back up into the center of the beam pipe.

“This research is very promising, and so is another method being developed at KEK that uses clearing electrodes,” said Pivi. (Read about the clearing electrodes approach to the electron cloud problem in symmetry.) SLAC has been leading the experimental effort on the electron cloud problem for future accelerators, including the International Linear Collider.

This story first appeared in SLAC Today.

Kelen Tuttle

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Physics Nobel for matter-antimatter difference and symmetry breaking

October 7, 2008 | 5:19 am

The 2008 Nobel Prize in Physics has been awarded to Yoichiro Nambu “for the discovery of the mechanism of spontaneous broken symmetry in subatomic physics”, and to Makoto Kobayashi and Toshihide Maskawa “for the discovery of the origin of the broken symmetry which predicts the existence of at least three families of quarks in nature”.

This work included a description of how quarks can change flavor, predicted a third generation of quarks, and gave details of one way in which matter and antimatter are not exactly the opposites of each other.

Nambu developed a mathematical description of spontaneously broken symmetry in particle physics, not only for quarks. Kobayashi and Maskawa developed the concept for how CP violation (responsible for some of the difference between how matter and antimatter act) could occur in the weak force, and how that is reflected in the interactions of quarks.

The work of Kobayashi and Maskawa is codified in what is known as the CKM Matrix (also named for Nicola Cabibbo). Kobayashi and Maskawa extended previous work by Cabibbo and proposed the three generations of quarks that are now known to exist.

Experimental determination of CP violation has been shown in various experiments such as that in kaons in 1964 (leading to the Physics Nobel for Val Fitch and James Cronin in 1980). More recent experiments done at the B factories–the BaBar detector at Stanford Linear Accelerator Center and the Belle detector at KEK in Japan–demonstrated an amount of CP violation just as predicted by Kobayashi and Maskawa.

It was really the predictions by Kobayashi and Maskawa that opened the possibility of seeing CP violation in B mesons and that led to the creation of the BaBar and Belle experiments.

The concept of spontaneous symmetry breaking was first introduced to particle physics by Yoichiro Nambu who studied the phenomenon in superconductivity. He translated those ideas to particle physics and ushered in the construction of the Standard Model of particle physics. The Higgs boson is thought to be responsible for particles acquiring mass, and that process is also an example of symmetry breaking.

The work recognized by the 2008 Nobel Prize in Physics is a key step in the long development of physicists’ understanding of the fundamental laws that govern the particles and their interactions.

More resources:
Nobel press release
Nobel information for the public
Nobel scientific information and history of symmetry breaking
Wikipedia: CP violation

Relevant articles in symmetry magazine:
Deconstruction: CKM matrix/Unitarity triangle
BaBar’s window on the weak force
explain it in 60 seconds: B factories
explain it in 60 seconds: The Standard Model
explain it in 60 seconds: CP violation
explain it in 60 seconds: antimatter

Other relevant Nobel Prizes in Physics:
2004: Gross, Politzer, Wilczek–asymptotic freedom in the strong force
1999: ‘t Hooft, Veltman–electroweak force
1990: Friedman, Kendall, Taylor–quark model
1980: Cronin, Fitch–symmetry breaking (CP violation) in K mesons
1979: Glashow, Salam, Weinberg–electroweak theory
1969: Gell-Mann–classification of elementary particles
1965: Tomonaga, Schwinger, Feynman–quantum electrodynamics
1957: Yang, Lee–parity violation

David Harris

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