Measurement of muon spin relaxation time in various scintillating materials

Abstract A new experimental method to search for T-violating transverse muon polarization (PT ) in the K+ → π 0 μ + ν decay was recently proposed. In this new experiment, the measurements of the μ + momentum vector, the π 0 momentum vector, and the μ + polarization will be performed by the same segmented calorimeter. One of key issues is the choice of a scintillation material which can maintain the μ + spin polarization for several μ + lifetimes. A test experiment to measure the μ + spin relaxation time in various scintillating materials was carried out at J-PARC Material and Life Science Facility (MLF). It was concluded that the residual μ + polarization in CeF3 is high enough to perform the proposed T-violation experiment.