Friday, January 07, 2011

Italy approves SuperB particle collider

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Jan 6, 2011

The Italian government has given final approval for building a new €500m collider that will investigate the small but significant differences between matter and antimatter. The SuperB facility will smash electrons and positrons together to produce particle/antiparticle pairs of B-mesons, D-mesons and tau-leptons. Measuring the subtle differences in how these particles and their antiparticles decay could help shed light on the mystery of why there is so much more matter than antimatter in the universe.

The SuperB facility will be built by Italy's national institute for nuclear and particle-physics research (INFN). It will consist of a 2 km circumference ring with two accelerators – one for electrons and the other for positrons. Collisions will occur within a large detector that will track the decay products and measure their energy.

The facility is expected to produce B-mesons at a rate 50–100 times greater than existing and previous "B factories" such as BaBar in the US and Belle in Japan. Marcello Giorgi from the INFN's lab in Pisa, who is director of the SuperB project board, says that the experiment could begin taking data by 2016.

SuperB will also produce synchrotron radiation, which will be used in a wide range of experiments in condensed-matter physics, chemistry, biology and materials science. The synchrotron facility will have six beamlines – three extracting light from the electron beam and three from the positron beam. Although this is a small number of beamlines compared with other synchrotron facilities, Giorgi told that "the brilliance of the light will be greater than any existing synchrotron".

The SuperB synchrotron, plans for which were finalized in February 2010, will be run by the Italian Institute of Technology (ITT). Once particle-physics experiments are finished at SuperB, the facility will eventually be devoted solely to synchrotron-radiation research. However, Giorgi, stresses that particle physics is the priority and he does not expect the matter/antimatter studies to be adversely affected by the synchrotron research.

Although the funding announcement has been delayed by a year – due in part to the global financial crisis – Giorgi expects work to begin on the facility later this year. Commissioning of the accelerator is scheduled for late 2015 and the first data should emerge in 2016. Physicists should be able to keep to this tight schedule because many of the accelerator components will be reused from the defunct PEP-II electron–positron collider at SLAC National Accelerator Laboratory in the US, which hosted the BaBar experiment until 2008.

Despite this tight schedule, the INFN has still not decided where to build the facility. The leading candidate is INFN's Frascati lab just outside Rome. Frascati is already home to the DAFNE electron–positron collider, which is used to study CP violation in K-mesons. Although the INFN site is not large enough to hold the entire ring, it could be shared with the adjoining Frascati campus of Italy's national energy research lab ENEA. According to Giorgi, the INFN is in the final stages of negotiating this plan, which includes building tunnels under a main road.

If the Frascati plan falls through, the alternative site is Rome's University of Tor Vergata, which is about 2.4 km from the Frascati lab. According to Giorgi, a site will be chosen by the end of January.

View the original article here

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