From CERN: “A fundamental property of the rarest element on Earth”

14 May 2013
Cian O’Luanaigh

“An international team of physicists at the radioactive-beam facility ISOLDE at CERN have for the first time measured the ionization potential of the rare radioactive element astatine.

Part of the resonance ionization laser ion source (RILIS) at ISOLDE (Image: ISOLDE/CERN)

The value for astatine, published today in the journal Nature Communications, could help chemists to develop applications for the element in radiotherapy, and will serve as a benchmark for theories that predict the structure of super-heavy elements.

The ionization potential of an element is the energy needed to remove one electron from the atom, thereby turning it into an ion. This measurement is related to the chemical reactivity of an element and, indirectly, to the stability of its chemical bonds in compounds.

See the full article here.

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From Symmetry: “Smallest lab-made drop of liquid might cause strange particle behavior”

A new result from the CMS collaboration takes a step toward revealing the origin of the mysterious ridge effect.

May 07, 2013
Kelly Izlar

“The Large Hadron Collider is known for a list of impressive facts—it’s the world’s largest and most powerful particle collider; it accelerates particles to nearly the speed of light; its cryogenic system keeps it colder than outer space.

Now it’s under consideration for a new superlative: Scientists there might have created the most minuscule drop of liquid ever formed in a laboratory.

Photo: Michael Hoch / CERN

Last year physicists collided protons with heavier lead ions in the LHC. They found a small but noticeable correspondence between the trajectories of charged particles that sped away from collisions. Newly produced particles appeared to be synced, like a school of fish moving in unison. They dubbed this phenomenon the ‘ridge effect.’

The CMS experiment (pictured above) studied more proton–lead collisions early this year, and the result, made public this week, suggests that the particles are behaving the way they do in lead–lead collisions, where they are swept along by a drop of plasma. If this is true, the drop formed in proton–lead collisions would be the smallest drop of liquid ever formed in a laboratory.”

See the full article here.

Symmetry is a joint Fermilab/SLAC publication.

From Symmetry: “Matter, antimatter, we all fall down—right?”

April 30, 2013
Ashley WennersHerron

Scientists perform the first direct investigation into how antimatter interacts with gravity.

What goes up must come down, the saying goes. But things might work a little differently with antimatter.
A CERN-based experiment has taken the first step in investigating exactly how antimatter interacts with gravity.

Photo: CERN

Atimatter particles should mimic those of matter particles. If it turns out that there is a difference, it will be a sign of dramatically new physics.
So far, no one has been able to test directly how antimatter interacts with gravity—but the ALPHA experiment has begun to try.

The ALPHA experiment’s main purpose is to trap and study antihydrogen atoms, the antimatter partners of hydrogen atoms. The antihydrogen atoms are held in place inside a tube by magnetic forces. Physicists on ALPHA have trapped more than 500 antiatoms since 2010. They keep them in their trap for up to about 16 minutes. When they turn off their magnets, the antiatoms fall out of the trap. A highly sensitive detector tracks the antiatoms and records where they first come in contact with matter and annihilate.”

See the full article here.

Symmetry is a joint Fermilab/SLAC publication.

From CERN and Symmetry Magazine: “LHCb experiment observes new matter-antimatter difference”

24 Apr 2013
No Writer Credit

A view of the LHCb underground area, looking upwards from the cavern floor (Image: Anna Pantelia/CERN)

“The LHCb collaboration at CERN today submitted a paper to Physical Review Letters on the first observation of matter-antimatter asymmetry in the decays of the particle known as the B0s. It is only the fourth subatomic particle known to exhibit such behaviour.

Matter and antimatter are thought to have existed in equal amounts at the beginning of the universe, but today the universe appears to be composed essentially of matter. By studying subtle differences in the behaviour of particle and antiparticles, experiments at the LHC are seeking to cast light on this dominance of matter over antimatter.

Now the LHCb experiment has observed a preference for matter over antimatter known as CP-violation in the decay of neutral B0s particles. The results are based on the analysis of data collected by the experiment in 2011. ‘The discovery of the asymmetric behaviour in the B0S particle comes with a significance of more than 5 sigma – a result that was only possible thanks to the large amount of data provided by the LHC and to the LHCb detector’s particle identification capabilities,’ says Pierluigi Campana, spokesperson of the LHCb collaboration . ‘Experiments elsewhere have not been in a position to accumulate a large enough number of B0s decays.’

Violation of the CP symmetry was first observed at Brookhaven Laboratory in the US in the 1960s in neutral particles called kaons. About 40 years later, experiments in Japan and the US found similar behaviour in another particle, the B0 meson. More recently, experiments at the so-called B factories and the LHCb experiment at CERN have found that the B+ meson also demonstrates CP violation.

All of these CP violation phenomena can be accounted for in the Standard Model, although some interesting discrepancies demand more detailed studies. ‘We also know that the total effects induced by Standard Model CP violation are too small to account for the matter-dominated universe,’ says Campana. ‘However, by studying these CP violation effects we are looking for the missing pieces of the puzzle, which provide stringent tests of the theory and are a sensitive probe for revealing the presence of physics beyond the Standard Model.’”

See the full CERN article here.

And now a different slant from Symmetry Magazine

Strange beauty particle decays boost matter

Photo: CERN via Symmetry Magazine

April 24, 2013
Kelly Izlar

“When the universe was less than a minute old, a tiny difference in the behavior of matter and antimatter led to the matter-dominated existence we experience today.

Today, particle physicists on CERN’s LHCb collaboration announced that, for the first time, they have observed particles called strange beauty mesons, or B0s, contributing to this imbalance.

Scientists found that in strange beauty particles, composed of beauty antiquarks bound with strange quarks, antimatter decays slightly more often than matter. This is called charge-parity, or CP, violation.

When B0s mesons decay to kaons and pions, physicists can determine if the new particles are matter or antimatter by looking at their relative charges. After comparing the number of matter particles with antimatter particles, they were able to confirm the findings.

‘It’s a simple idea, although getting there is quite complicated, says Tara Shears, a physicist on LHCb. ‘We’re looking at a very small discrepancy that reflects the nature of the universe.’

LHCb’s result has a statistical significance exceeding five sigma—the gold standard for declaring a discovery in particle physics.

‘We had about one thousand B0s candidates to measure,’ says Shears. ‘The results unambiguously support predictions that these particles violate CP.’

In the 1960s, James Cronin and Val Fitch observed CP violation in neutral kaons. About 40 years later, another particle, the B0 meson, showed similar behavior in the BaBar and Belle detectors in the United States and Japan. Recently, these experiments and LHCb also observed CP violation effects in B+ meson decays.

However, the Standard Model predicts only a tiny portion of the amount of CP violation needed to explain the huge deficit of antimatter in the universe. While these results help scientists understand the mechanics of CP violation, the case of the missing antimatter remains unsolved.

“We expected a certain amount of CP violation to be found in the strange beauty system,” says Pierluigi Campana, the LHCb spokesperson. “But finding the missing fraction of CP violation in the early universe will be new physics, which the Standard Model can’t predict.”

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From CERN: Fabulous Photo and “CMS prepares for the future”

23 Apr 2013
Austin Ball, Achintya Rao

“While the Large Hadron Collider (LHC) takes a break for its first long shutdown, the CMS collaboration are busy maintaining and consolidating the detector to be sure to handle the collider’s improved performance from 2015 onwards.

The biggest priority for CMS is the tracker performance. The CMS tracking system forms the innermost subdetector and fits snugly round the LHC beampipe. It must withstand an onslaught of some 1010 particles a second and the aggressive field of mixed radiation that this produces.

Another major element is to improve the muon detectors with a fourth endcap layer to help discriminate between interesting muons and fake signatures or background. New shielding discs, 10 centimetres deep, are to be installed on either end of the detector. Each shielding disc is made of 12 iron sector-casings filled with a special concrete. The concrete, developed for this specific application by CERN’s civil engineers, is almost 50% denser than normal concrete – it is made using haematite (or ferric oxide) instead of the usual sand – and it is loaded with boron to absorb low-energy neutrons that would otherwise give rise to unwanted hits in the detector.”

See the full article here.

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From CERN: “Two-beam module to drive particle beams”

22 Apr 2013
Cian O’Luanaigh

“It may look like a steampunk locomotive, but this first prototype module for the Compact Linear Collider (CLIC) won’t be carrying any passengers. CLIC is a concept for a two-beam linear accelerator to collide electrons and positrons (antielectrons) head-on at energies up to several teraelectronvolts (TeV).

The first prototype module for the Compact Linear Collider is being tested at CERN (Image:Anna Pantelia/CERN)

The module above – the first of its kind – is being tested at CERN, with neither beam nor radiofrequency (RF) system. The CLIC two-beam module team is checking the feasibility of the engineering designs for the different technical systems, such as the RF structures, the support structures, the alignment, stabilization and vacuum.”

In the CLIC machine, energy is extracted from a low-energy, high-intensity electron beam to drive a parallel beam of particles The main linear accelerators (linacs) have a modular design based on 2-metre long two-beam modules, and will operate under ultra-high vacuum conditions required for beam physics.

CLIC

See the full article here.

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From Symmetry: “LHC passes ‘ping-pong ball’ test”

Physicists sent an ultra-clean, miniature ping-pong ball through part of the Large Hadron Collider beam pipe to test for hidden defects.

April 16, 2013
Ashley WennersHerron

“Sometimes the best solutions in high-energy physics research are surprisingly low-tech.

Physicists sent a carefully sterilized, slightly-smaller-than-regulation ping-pong ball through a 2-mile section of the Large Hadron Collider today. They were searching for possible defects in the connections between magnets that can arise as they change temperature.

The so-called radio-frequency ball, first developed in 2007, carried a small transmitter that allowed scientists to track its progress. It moved through simple suction, pinging every third of a mile.

‘The beam pipes are fragile,’ says Vincent Baglin, the leader of the LHC beam vacuum section at CERN. ‘We always have to check and crosscheck to minimize any problems. This is a simple test that can prevent complicated issues.’”

See the full article here.

Also, see this article from CERN.

Symmetry is a joint Fermilab/SLAC publication.

From CERN: “Opening the LHC – in pictures” Don’t Miss this one.

If you want to really see where your tax money is going, do not miss this article from CERN

12 Apr 2013.
Cian O’Luanaigh

This week technicians opened up the first interconnections between magnets on the Large Hadron Collider (LHC) to work on the accelerator components inside. Above, a technician prizes the thermal insulation plates from an interconnection between LHC magnets. Note the bicycles, which workers use to get around the LHC tunnel.

All images by Maximilien Brice for CERN.

There are two more terrific shots. Take a peak. The article is here.

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From CERN: “The LHC at level best”

April 9 2013
Katarina Anthony

“The Large Hadron Collider (LHC) tunnel is renowned for its geological stability: set between layers of sandstone and molasse, it has allowed the world’s largest accelerators to run to sub-millimetre precision. But even the most stable of tunnels can be affected by geological events. To ensure the precise alignment of the LHC, the CERN survey team performs regular measurements of the vertical position of the magnets (a process known as “levelling”).

CERN surveyors take levelling measurements of the LHC magnets (Image: CERN)

The team has taken measurements of the LHC before its temperature reached 100 K, beyond which there may be some mechanical movements. As no data could be gathered while the machine was in operation, these measurements will provide the clearest picture yet of the accelerator’s position at the end of its run. The team used a so-called “fast levelling” technique, which involves measuring every second magnet in order to complete the survey as quickly as possible and to reduce the influence of the environmental conditions that could affect the observations made with an optical level. Technicians were able not only to measure the height of the magnets but also to make immediate height comparisons with the previous magnets. No magnet realignments were carried out at this stage.

‘By comparing these measurements with the base measurements taken during the 2008-2009 shutdown, we will soon have an accurate picture of how ground disturbances may have affected the machine,’ says Dominique Missiaen, leader of the Beams department section responsible for large-scale metrology. ‘This comparison will also help us predict possible future deviations and deterioration of the relative positions between magnets.’”

See the full article here.

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From CERN: "First result from the AMS experiment"

30 March 2013
No Writer Credit

“The Alpha Magnetic Spectrometer (AMS) Collaboration announces the publication of its first physics result in Physical Review Letters. The AMS Experiment is the most powerful and sensitive particle physics spectrometer ever deployed in space. As seen in Figure 1, AMS is located on the exterior of the International Space Station (ISS) and since its installation on 19 May 2011 it has measured over 30 billion cosmic rays at energies up to trillions of electron volts. Its permanent magnet and array of precision particle detectors collect and identify charged cosmic rays passing through AMS from the far reaches of space. Over its long duration mission on the ISS, AMS will record signals from 16 billion cosmic rays every year and transmit them to Earth for analysis by the AMS Collaboration. This is the first of many physics results to be reported.

From its vantage point ~260 miles (~400 km) above the Earth, the Alpha Magnetic Spectrometer (AMS) collects data from primordial cosmic rays that traverse the detector.

In the initial 18 month period of space operations, from 19 May 2011 to 10 December 2012, AMS analyzed 25 billion primary cosmic ray events. Of these, an unprecedented number, 6.8 million, were unambiguously identified as electrons and their antimatter counterpart, positrons. The 6.8 million particles observed in the energy range 0.5 to 350 GeV are the subject of the precision study reported in this first paper.

Electrons and positrons are identified by the accurate and redundant measurements provided by the various AMS instruments against a large background of protons. Positrons are clearly distinguished from this background through the robust rejection power of AMS of more than one in one million.

Currently, the total number of positrons identified by AMS, in excess of 400,000, is the largest number of energetic antimatter particles directly measured and analyzed from space.”

From AMS at NASA
“The AMS-02 experiment is a state-of-the-art particle physics detector that is constructed, tested and operated by an international team composed of 56 institutes from 16 countries and organized under United States Department of Energy (DOE) sponsorship. The JSC (Johnson Space Center) AMS project office oversaw the overall payload integration activities and ensured that the payload is safe and ready for launch on the Space Shuttle and and continues to be safe since its deployment onto the ISS. The AMS Experiment uses the unique environment of space to advance knowledge of the universe and lead to the understanding of the universe’s origin. AMS was launched on Space Shuttle Endeavour on May 16, 2011.” Operations on the ISS began three days later, and AMS continues operations onboard the ISS today.”

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