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Friends and Colleagues of Raju Raghavan Gather to Honor His Life in Science

      On Saturday, October 20th the one year anniversary of his death, friends and colleagues of Prof. Raju Raghavan gathered at Virginia Tech to pay tribute to his versatile and creative life in science. The Symposium on the Life and Science of Raju Raghavan featured talks from throughout his career. Speakers included: Sandip Pakvasa of the University of Hawaii, who talked about Raju as a graduate student; Daniel Murnick of Rutgers and Loren Pfeiffer of Prinecton who talked about Raju's Career at Bell Labs; Franz von Feilitzsch of Technische Universität München who talked about Raju's contributions to Borexino; Atsuto Suzuki, Director General of KEK,who talked about Raju's contributions to KamLAND; and many others.
Portrait of Symposium Participants

      Many of Raju's friends who could not make the Symposium in person watched the live web stream, which is still available on YouTube.

Virginia Tech Hosts the International Neutrino Summer School

      The Center for Neutrino Physics, the Department of Physics and the College of Science hosted the International Neutrino Summer School from July 10th through July 21st, 2012. The two week school was attended by more than 70 postdoctoral and graduate students from 14 different countries. Students attended lectures given by top researches from around the world. The lectures included topics such as neutrino oscillations, neutrino mass, leptogenesis (a theory in which neutrinos may be responsible for the matter-antimatter asymmetry in the universe), neutrinos in cosmology and astrophysics, neutrino interactions, the physics of neutrino detection, and experiments with neutrinos from the upper atmosphere, accelerators, nuclear reactors and the Sun. In addition to attending lectures students worked in groups to solve problems such as designing experiments to measure critical neutrino properties.
Portrait of INSS Participants

      The International Neutrino Summer School was sponsored by the Virginia Tech College of Science, the VT Physics Department, the Center for Neutrino Physics, Fermi National Accelerator Laboratory, the US Department of Energy, the National Science Foundation, The Sanford Underground Research Facility, Lawrence Berkeley National Laboratory and Oak Ridge National Laboratory.

Daya Bay Measures the Neutrino Mixing Parameter sin213

      In a letter submitted to the Physical Review (arXiv:1203.1669[hep-ex]), the Daya Bay Collaboration, including mebers of Virginia Tech's Center for Neutrino Physics, announces the first observation and measurement on the neutrino mixing parameter sin213. The mixing angle θ13 governs the rate of electron neutrino conversion to muon and tau neutrinos at baselines consistent with atmospheric oscillations. The hunt for theta;13 is currently the focus of several major experiments world wide, who are using either electron antineutrinos from nuclear reactors or beams of muon neutrios/anitneutrinos produced at accelerators.

      In reactor neutrino experiments such as Daya Bay, the oscillation is observed as an electron antineutrino disappearance at a distance of about 2 km from the reactor. The effect can only be measured with confidence in the comparison of detectors placed near the reactor cores – which measure the neutrino flux before significant oscillation has occured – to detectors placed farther away – at a location close to the oscillation maximum. In this way uncertainties associated with antineutrino production in the reactor, the interaction cross section in the detector, and to a lessor degree detector efficiency will cancel in the near/far detector comparison. Daya Bay Collaboration is the first to apply this technique and report results, finding:

sin213=0.092±0.016(stat.)±0.005(syst.).

The measured vs. expected signal in each detector, assuming no oscillation. Reactor and survey data are used to compute the weighted average baselines. The oscillation survival probability at the best fit value is given by the smooth curve.

Read the full press release.

Borexino Sees First Evidence of Neutrinos from the Rare pep Solar Fusion Process

      In a recently published article (Phys.Rev.Lett. 108, 051302) the Borexino Collaboration, including members of the Virginia Tech group lead by Prof. Bruce Vogelaar, announced a first ever observation of neutrinos from the sun consistent with the rare fusion process in which two light hydrogen nuclei, or protons, combine with an electron to make a heavy hydrogen nucleus, known as a duteron, and an electron neutrino. This process know as pep fusion is about 500 times less likely than the primary pp process in which a two protons combine to to make a duteron, and electron and an electron neutrino. While neutrinos from the pp fusion process are much more common, neutrinos from the pep process have higher energies, which makes it possible for them to be seen in the Borexino detector.

      The Borexino observation is consistant with the Standard Solar Model prediction for flux of neutrinos from the pep fusion combined with the best fit model of neutrino oscillations.
See the Article in APS Spotlight

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Leo Piilonen, of the Center for Neutrino Physics, has been elected as one of the spokespersons of the Belle Collaboration. As spokesperson, Prof. Piilonen will help guide the collaboration as they undertake the major upgrade of the experiment to Belle II.

CNP Director, Leo Piilonen, was selected as next Chair of the Physics Department. Jonathan Link was selected to succeed Piilonen as Director of CNP.