From CERN: “CERN’s ISOLTRAP reveals new magic in the atomic nucleus”

19 June 2013
Cian O’Luanaigh

“The ISOLTRAP collaboration has measured the mass of exotic calcium nuclei using a new instrument installed at the ISOLDE facility at CERN. The measurements, published on 20 June in the journal Nature, clearly establish a new ‘magic number’ related to the stability of this exotic species. The results cast light on how nuclei can be described in terms of the fundamental strong force.

Part of the ISOLTRAP experimental apparatus at CERN (Image: CERN)

‘This measurement from a classic ISOLDE low-energy experiment complements well recent key results on radon, observed by post-accelerated beams, and on astatine, observed at the source with lasers,’ said CERN’s Director-General, Rolf Heuer. ‘It demonstrates beautifully that ISOLDE has a wealth of tools for producing exciting physics.’

The results strengthen the prominence in calcium isotopes of a magic number that was not foreseen in the original ‘nuclear shell model’, for which Maria Goeppert-Mayer and Hans Jensen received the Nobel Prize in 1963, exactly 50 years ago. In this model, the protons and neutrons in a nucleus arrange themselves in ‘shells’ similar to those of electrons in atoms. The magic numbers correspond to full nuclear shells, in which the constituents are more tightly bound, leading to more stability and lighter masses.

The ISOLTRAP team used the ISOLDE facility to make exotic isotopes of calcium, which has the magic number of 20 protons in a closed shell. Their goal was to find out how the shell structure evolves with increasing numbers of neutrons. Standard calcium with 20 neutrons is doubly magic, and a rare long-lived isotope has 28 neutrons – another magic number.

Now, the ISOLTRAP team has determined the masses of calcium isotopes all the way to calcium-54, which has 34 neutrons in addition to the 20 protons. The measurements not only reveal a new magic number, 32, but also pin down nuclear interactions in exotic neutron-rich nuclei.”

The full article is here.

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From Fermilab: “Cranking it up to 11: a new superconducting magnet”

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

Tuesday, June 18, 2013
Leah Hesla

“Like the famous volume controls in This Is Spinal Tap, a new magnet developed by CERN and Fermilab goes to 11. But unlike the dubiously labeled amplifier, the magnet doesn’t just say it goes to 11, it really does. 11.7, in fact.

Fermilab’s Technical Specialist Marty Whitson installs the 11-Tesla niobium-tin dipole magnet inside a bolted skin. Photo: Fermilab

Pushing past 11 Tesla is a goal that both laboratories have been working on since they combined forces three years ago to develop stronger magnets for the LHC upgrade. It’s a remarkable achievement for the accelerator community.

‘There were many happy e-mails going around,”‘said 11-Tesla Project Leader Mikko Karppinen, of CERN.

For more than 10 years, Fermilab has been working to develop accelerator magnets with high fields using niobium-tin superconductor. In March, the High-Field Magnet Group announced a new milestone: In collaboration with the High-Luminosity LHC project at CERN, the group developed a niobium-tin magnet that broke the 11-Tesla barrier.

‘When we heard about the need at CERN to develop these 11-Tesla magnets, we offered our help here,’ said Fermilab’s Alexander Zlobin, head of the High-Field Magnet Program. ‘For us this was a good opportunity to implement niobium-tin technology in a real machine.’

11 Tesla isn’t an arbitrarily chosen value. The LHC is planning to use shorter magnets to make room in its tunnel for new instruments that will help narrow the particle beam, protecting the LHC ring from beam losses. But if the magnets must be shorter, they must also be stronger to compensate. The LHC currently uses niobium-titanium magnets at their maximum of 8.33 Tesla. The niobium-tin magnets will kick it up a few notches.”

See the full article here.

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.

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From CERN: “EuCARD-2 kicks off”

18 Jun 2013
Marina Giampietro

“Last week CERN hosted a number of events that focused on research and development for particle accelerators.

EuCARD-2 aims to foster new ideas for next-generation particle accelerators (Image: Anna Pantelia/CERN)

On Monday speakers presented the results of the EuCARD project – a common research-and-development venture of 39 partners involved in accelerator sciences and technologies in Europe. In a 2-day workshop experts discussed the future of accelerators, predicting their technical needs for the next 50 years. Then on Thursday and Friday, EuCARD-2 – an R&D project for the next generation of accelerators – was officially launched.

The project, coordinated by Maurizio Vretenar from CERN, will last four years, managing a budget of €23.4 million of which one third is from the European Commission. ‘This project builds on the success of EuCARD in joining large laboratories with the intellectual potential of small institutes and universities,’ says Vretenar. ‘EuCARD-2 aims to become an important actor in fostering new ideas and technologies for the future of accelerators and in enhancing their impact on the society.’”

See the full article here.

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From CERN: “Lighting the torch for ELENA”

17 Jun 2013
Cian O’Luanaigh

“A ground-breaking ceremony today marked the start of construction of an extension to CERN’s antimatter facility. Infrastructure currently housed in the Antiproton Decelerator (AD) hall will be moved into this extension to make space for a new decelerator, the Extra-Low-Energy Antiproton ring (ELENA).

CERN Director-General Rolf Heuer gets stuck in at the ground-breaking ceremony for ELENA (Image: Anna Pantelia/CERN)

This cooling ring, about 30 metres in circumference, will further slow the 5.3 MeV antiprotons ejected from the AD down to 100 keV to increase the number of antiprotons that can be trapped by antimatter experiments.

ELENA is designed to decelerate antiprotons in a well controlled way and to further reduce beam sizes and energy spreads with an electron cooler to increase the efficiency of deceleration, resulting in more trapped antiprotons.

Design is also under way for a new experiment – GBAR – that will be installed at the same time as ELENA; and the BASE collaboration has recently suggested adding an experiment to increase the precision of a measurement of the antiproton’s magnetic moment by a factor of 1000. As well as more usable (or trappable) antiprotons, ELENA will be able to deliver beams almost simultaneously to four antimatter experiments resulting in an essential gain in total beam time for each experiment.

There is much to explore in the field of antimatter; many theoretical predictions in the antimatter regime remain experimentally unverified. ELENA will increase CERN’s capacity to accommodate research groups wishing to perform experiments in the increasingly popular field of antihydrogen and low-energy antiproton physics.”

See the full article here.

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From Brookhaven Lab: “RHIC’s Perfect Liquid a Study in Perfection”

Brookhaven Lab

June 17, 2013
Karen McNulty Walsh

Systematic analysis of particle flow in heavy ion experiments suggests that RHIC’s shear viscosity is close to ideal limit

“When heavy ions (the nuclei of heavy atoms such as gold and lead) collide at high energies at Brookhaven National Laboratory’s Relativistic Heavy Ion Collider (RHIC) and Europe’s Large Hadron Collider (LHC), the components of the nuclei (protons and neutrons) melt to form a hot soup of their constituent particles, quarks and gluons. A new model that accurately describes the experimentally observed patterns of particles flowing out from this ‘quark-gluon plasma’ (QGP) suggests that the effective shear viscosity, or resistance to flow, is close to the ideal limit used to define a ‘perfect’ fluid.

Bjoern Schenke, right, chats with fellow Brookhaven Lab nuclear theorist Raju Venugopalan, at last summer’s Quark Matter meeting in Washington, D.C. Schenke recently won a Young Scientist Prize in nuclear physics from the International Union of Pure and Applied Physics.

‘Our result is consistent across finer and finer detailed analyses of particle flow patterns,’ said Bjoern Schenke, a Goldhaber Fellow in the nuclear theory group at Brookhaven Lab and a coauthor on a paper describing the analyses in Physical Review Letters published earlier this year.

‘These findings help answer the question of how perfect the perfect liquid QGP created at RHIC is—that is, how close the viscosity comes to a limit derived from quantum mechanics—and how this property varies with temperature. Our findings indicate that viscosity increases away from the ideal limit with the increasing temperatures reached at LHC,’ Schenke said.

The findings will also help scientists better understand how the internal characteristics of the heavy ions before they collide—particularly dense concentrations of gluons known as color glass condensate—shape the initial collision geometry and rapidly turn into the liquid quark-gluon plasma. “

See the full article here.

One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.

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From Fermilab- “Frontier Science Result: CMS Looking in many boxes”

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

Friday, June 14, 2013
Don Lincoln

Dr.Don Lincoln

“In February, I wrote an article that described a search for the smallest building blocks of matter. Currently, the best description we have of the subatomic realm is the Standard Model, and this theory treats particles called quarks and leptons as having no size at all. On the other hand, the history of physics is full of particles that were once thought to be the smallest of the small and turned out not to be: Atoms, atomic nuclei and protons are the best known ones.

Standard Model

If there are particles smaller than the ones we know, then there is some sort of force that binds the smaller particles into the familiar quarks and leptons. When we begin to probe the smaller scale, we expect to encounter new physics, and the character of the data will change. Because these changes will be caused by contacting the new physical phenomena, these kinds of pursuits are called contact interactions, and the math treats the interactions as if the particles actually come into contact.

Searching for particles smaller than any previously discovered requires looking into lots of different boxes. An earlier search using leptons was unsuccessful, so this analysis turned to quarks.

In the earlier article, I described how CMS scientists were searching for contact interactions in the production of leptons. This allows physicists to see if there is new physics to be found at the smallest scales when investigating electrons and muons.

There is no guarantee that leptons are the right place to search for new phenomena. Leptons may be sufficiently point-like that we can’t see contact interactions using our equipment. However, it is possible that quarks and gluons are less point-like than leptons. Accordingly, it is important also to check the data for contact interactions for quarks. CMS has looked for any evidence of new physics occurring at very small scales when quarks are scattered. No evidence for unexpected contact interactions was discovered.”

See the full article with links here.

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.

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From CERN: “International Linear Collider ready for construction”

12 Jun 2013
Cian O’Luanaigh

“Today the Linear Collider Collaboration published its Technical Design Report [PDF] for the International Linear Collider (ILC) – a proposed 31-kilometre electron-positron collider that will both complement and advance beyond the physics of the Large Hadron Collider.

A schematic of the layout of the International Linear Collider – note the soccer pitch for scale (Image: Pablo Vazquez )

In three consecutive ceremonies in Asia, Europe and the Americas, the authors officially handed the report over to the international oversight board for projects in particle physics, the International Committee for Future Accelerators (ICFA). The report presents the latest, most technologically advanced and most thoroughly scrutinized design for the ILC.

The ILC will accelerate and collide electrons and their antiparticles, positrons. Collisions will occur roughly 7000 times per second at the collision energy of 500 GeV. Some 16,000 superconducting cavities will be needed to drive the ILC’s particle beams. The report also includes details of two state-of-the-art detectors that will record the collisions, as well as an extensive outline of the geological and civil engineering studies conducted for siting the ILC.

‘The Technical Design Report is an impressive piece of work that shows maturity, scrutiny and boldness,’ says Lyn Evans, director of the Linear Collider Collaboration. ‘The International Linear Collider should be next on the agenda for global particle physics.’”

See the full article here.

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From Fermilab: “DZero collaboration meeting reviews Tevatron legacy”

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

No one should ever forget the value of the work of the Tevatron. The work of the Tevatron led directly to the success of the LHC.

Monday, June 10, 2013
No Writer Credit

“This week the DZero collaboration is holding a workshop on the plains of DeKalb, Ill., as it plans its final campaign to review the legacy of the Tevatron. This is the 30th year that DZero has held its regular week-long workshops. With the unique Tevatron proton-antiproton data set, fully developed particle identification and well-established computing in hand, the experiment analysis teams are in position to address the most important topics of particle physics. At the workshop, scientists are discussing plans for the publication of more than 50 legacy results from the full Tevatron data set, including precision measurements of such fundamental Standard Model parameters as masses of the top quark and W boson and result combinations with the CDF and LHC experiments. Learn more about this week’s workshop.

Large particle collider experiments tackle a panoply of distinct physics questions, each of which requires inputs from many algorithm and calibration tools. Weaving these disparate threads into a coherent tapestry requires a huge effort. The DZero collaboration has used these week-long collaboration-wide workshops to step back and view the overall effort and provide comprehensive guidance.

Tevatron

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.

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From Fermilab: “Choreographing the Accelerator and NuMI Upgrade”

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

“More than a year ago, Fermilab Engineering Physicist Cons Gattuso hung in his Cross Gallery office a large pin board covered with notes and strung with ribbons of different colors. The many-colored diagram, with its numerous and moveable parts, laid out the grand and dynamic plan for completing Fermilab’s Accelerator and NuMI Upgrade.

The Accelerator Division recently installed these two radio-frequency cavities in the Main Injector tunnel as part of Fermilab’s Accelerator and NuMI Upgrade. Photo: Marty Murphy, AD

The plan’s elaborateness is evident in the numbers. Since the beginning of the shutdown in April 2012, more than 300 employees—roughly 18 percent of the laboratory’s workforce—have contributed directly to the upgrade. Together, they have pulled 1 million feet of cable, handled more than 450 tons of material, reworked 1,500 feet of the new transfer line section and modified 10 percent of the vacuum system.

Led by members of the Accelerator Division, engineers and technicians from across the laboratory have been working for the last 13 months to prepare Fermilab’s Main Injector accelerator, the Recycler storage ring and the NuMI beamline to deliver proton beams of higher power than previously obtained. They have also been upgrading the NuMI target to handle the higher-intensity beams used for the NOvA experiment. These upgrades are an essential part of the laboratory’s shift to focus on Intensity Frontier research programs.

In a few weeks, the upgrade will be complete. It has been a project of complex choreography—hence the ribbon board, where each ribbon represents a crew’s workflow.

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.

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From Symmetry: “Three decades of the Z”

May 31, 2013
Kelly Izlar

Thirty years ago this week, CERN scientists announced the discovery of the Z boson, an elusive elementary particle that transmits the weak force.

“On June 1, 1983, physicists at CERN’s proton–antiproton collider called a press conference and made a long-awaited announcement: They had directly observed the Z boson. (One of the first Z-boson observations is shown in the image [below].)

Courtesy of: CERN

The discovery was greeted with both jubilation and sighs of relief as it confirmed the electroweak theory, a cornerstone of the Standard Model of particle physics upon which physicists had been relying for some time.

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.

Just a few months previous, CERN researchers had announced the discovery of the W boson. Together, these two bosons carry the weak force, which is responsible for the radioactive decay of particles.

Despite its name, the weak force is actually one of the stronger fundamental forces, but its influence is limited by the large mass of the Z and W bosons. Their size caps the range of the weak force at about a quintillionth of a meter, and it becomes negligible beyond the radius of a single proton.

Enrico Fermi was the first to put forth a theory of the weak force in 1933, and Sheldon Lee Glashow, Abdus Salam and Steven Weinberg developed its present form in the 1960s when they proposed that the weak and electromagnetic forces are actually different manifestations of a single electroweak force.

Carlo Rubbia, head of the UA1 collaboration, and Herwig Schopper, CERN director general, announce the discovery of the Z boson.
Photo: CERN

After the initial discovery in 1983, scientists at Z-boson factories at CERN and SLAC National Accelerator Laboratory studied millions of the bosons in great detail.

The Z boson also turned out to be very important when it came time to search for the Standard Model’s missing piece: the Higgs boson.

When scientists announced in 2012 that they had observed a new particle consistent with the Higgs boson, they had not directly observed the Higgs—the Higgs decays far too quickly for that. Instead, they had observed the particles into which the Higgs decays, including the Z boson.

See the full article here.

Symmetry is a joint Fermilab/SLAC publication.