Symmetry-Tests in Semileptonic Weak Interactions: A Search for New Physics

CPviolation in beta decay and electric dipole moments

“…The most general set of β-decay interactions can be parametrized at the quark level by an effective Lagrangian [5] …”

“…(5). The R coefficient, corresponding to the T-odd β-decay correlation J · σ e × p e where σ e is e ± polarization, has greater sensitivity to scalar-and tensor-type CP violation [5,6]. Moreover, these couplings are correlated with CP-odd tensor and scalar electron-nucleon couplings, which are strongly constrained by 199 Hg [23] and 205 Tl [24] EDM bounds, respectively [43,44,45,46,47].…”

“…The RPV MSSM is defined by adding to the MSSM superpotential gauge-invariant and renormalizable terms that violate either baryon or lepton number (but not both, to avoid proton decay) [30]. Contributions to D t are generated by the baryon number-violating terms 5 W…”

“…(See Refs. [5,6,7,8] for reviews of fundamental symmetry tests in β-decay.) In this work, we study the so-called D correlation, corresponding to the triple product J · p e ×p ν , where J is nuclear polarization, and p e (p ν ) is the e ± (ν) momentum.…”

Nuclei as Laboratories: Nuclear Tests of Fundamental Symmetries

“…Another interesting tool for probing new weak scale physics with β-decay is to study the spectral shape, spatial distribution, and polarization of the outgoing β particles. These characteristics of the spectrum are described by various correlations, as noted many years ago by Jackson, Treiman, and Wyld [33] ( for recent discussions, see also [34,35,36]) . For our purposes, it is useful to write the partial rate as…”