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Physicists to help build most precise particle detector

September 4, 2014

A team of physicists from Indiana University’s Center for Exploration of Energy and Matter has been awarded $1.2 million to help develop a new, highly precise particle detector that will be used to investigate the fundamental properties of elementary particles.

Anselm Vossen, a research scientist in IU Bloomington’s Department of Physics in the College of Arts and Sciences, and electronics engineers Brandon Kunkler and Gerard Visser will lead in the development of electronics for the particle detection systems of the Belle II detector. The detector will be located in Japan at the new SuperKEKB particle accelerator and will work at the interaction region of the accelerator’s electron and positron beams to make measurements of fundamental parameters underlying the Standard Model Theory of particle physics.

Belle II is expected to make measurements with a precision that has not been reached at any prior experiment, and its data could be sensitive to signals of physics beyond the Standard Model theory that could not be observed at any other facility currently in operation, Vossen says. The Standard Model is a well-tested theory that describes subatomic particles and their interactions, yet is deficient in other ways, such as identifying a candidate for dark matter or solving the matter-antimatter asymmetry of the universe.

Belle II follows its predecessor, the Belle experiment, which in 2001 demonstrated charge parity violation, or particle-anti-particle symmetry breaking, that had been predicted by Makoto Kobayashi and Toshihide Maskawa, winners of the 2008 Nobel Prize in Physics. Charge parity violation is believed to be one of the origins for the observed dominance of matter over anti-matter in our present universe, and Belle II aims to collect 50 times more data than the earlier experiment.

“Our engineers here at CEEM have already played a leading role in other nuclear and high-energy physics experiments, most notably the STAR experiment at the Department of Energy’s Brookhaven National Laboratory,” Vossen says. “It’s these qualified engineers coupled with our laboratory resources that played a large role in obtaining this funding.”

IU contributed to the STAR detector — the Solenoidal Tracker at Relativistic Heavy Ion Collider — at Brookhaven by designing and constructing its Endcap Electromagnetic Calorimeter, a device designed to see how gluons, the particles that bind quarks within protons, contribute toward the angular momentum of protons.

The Department of Energy’s Office of Science is providing the funding for the new project, which is being led by the Pacific Northwest National Laboratory.

The physics interest of the IU group focuses on the mechanism of how almost massless quarks, which cannot be observed directly, form observable particles called hadrons, the most stable of which are the protons and neutrons that compose atomic nuclei. There are two types of hadrons — mesons and baryons (protons and neutrons are baryons) — that can be observed, and IU physicists want to better understand how these formation processes depend on the quantum numbers of parent quarks.