Sampa Bhadra  Ph.D. (Colorado) Professor of Physics  This e-mail address is being protected from spambots. You need JavaScript enabled to view it Research Field: High Energy Physics Research specialization: Experimental particle physics (see http://www.hep.yorku.ca). Publications

I am currently working on the T2K experiment in Japan, which probes the properties of the elusive neutrino. The neutrino plays a key role in unsolved problems in particle physics and cosmology. The consequence of the breakthrough discovery that neutrinos have mass (by the experiments SuperK in Japan and SNO in Canada), contrary to the assumption in the Standard Model of particle physics, gives rise to quantum mechanical mixing among the 3 known neutrinos, encoded in matrix form. One of goals of T2K was to determine the last unknown parameter in this matrix, theta_13, which is accessible by studying the transformation of muon neutrinos to electron neutrinos. T2K has shown that theta_13 is non-zero and relatively large and this was published in Physical Review Letters 107, 041801 (2011). T2K was awarded a prestigious prize by La Recherche, a French science magazine, for finding the first indications of these types of oscillations. This dramatic discovery implies that the matter-antimatter asymmetry of the universe could be due to neutrino physics. We plan to investigate this possibility by comparing results from data collected with neutrino and anti-neutrino beams.

At T2K beams of neutrinos and anti-neutrinos are produced from protons hitting a graphite target. Precise monitoring of this proton beam is essential for understanding the neutrino flux, which is an input for physics studies. One of the monitoring devices, an Optical Transition Radiation (OTR) detector, is critical for measuring the proton beam characteristics in the high radiation environment near the target. The OTR detector along with its data acquisition system was designed, installed and commissioned by my group, with TRIUMF and University of Toronto collaborators. We have published a long paper in Nuclear Instruments and Methods describing the OTR system and its performance (http://dx.doi.org/10.1016/j.bbr.2011.03.031).

We are currently in an exciting phase of data taking and physics results withT2K. We are also looking into R&D for future experiments. Students having an interest in experimental studies at the cutting edge of fundamental physics are strongly encouraged to inquire about graduate positions in my group.