This paper describes new attempt to construct a highly-intense muon source called PRISM and an experimental search for lepton-flavor-violating ยต -e conversion processes at a sensitivity of the 10 -18 level with PRISM.
Lepton Flavor Violation
1.1. Physics Motivation
Lepton flavor violation (LFV) of charged leptons has been attracting much interest from theorists and experimentalists because of its recentlyrising potentials of finding clues to new physics beyond the standard model [1]. Recently, neutrino oscillations have been confirmed experimentally from various experiments such as Super-Kamiokande, KamLAND and K2K. One might wonder how the neutrino mixing affects LFV in charged leptons. The contribution has been calculated and turned out to be very small, of the order of 10 -50 . Therefore, discovery of LFV of charged leptons would indicate definite signature of new physics (phenomena) beyond the standard model.
Various theoretical models predict the existence of LFV processes of charged leptons at certain levels. They are, for instance, supersymmetric (SUSY) models, models of heavy neutrinos, leptoquarks, compositeness, two Higgs doublet models, models with heavy extra gauge bosons, and models of extra dimensions. In particular, in SUSY models, the ยต -e transition could occur through the slepton (ฮผ-แบฝ) mixing. It comes from off-diagonal matrix elements in the slepton mass matrix. In minimum supersymmetric standard models (MSSM), however, no off-diagonal terms exist at the Planck scale. And therefore in addition to SUSY itself, additional mechanisms are needed to produce non-zero off-diagonal elements via radiative corrections. They are, for instance, such as (a) grand unification (SUSY-GUT), or (b)