Supersymmetric contributions to weak decay correlation coefficients

Abstract

We study supersymmetric contributions to correlation coefficients that characterize the spectral shape and angular distribution for polarized -and -decays. In the minimal supersymmetric standard model (MSSM), one-loop box graphs containing superpartners can give rise to non-V ÿ A V ÿ A fourfermion operators in the presence of left-right or flavor mixing between sfermions. We analyze the present phenomenological constraints on such mixing and determine the range of allowed contributions to the weak decay correlation coefficients. We discuss the prospective implications for future -and -decay experiments, and argue that they may provide unique probes of left-right mixing in the first generation scalar fermion sector.

Prospects for precision measurements in nuclear decay in the LHC era

“…As expected, the interval for the allowed values of Re(C T + C T )/C A from the 6 He experiment is dominated by the contribution of the Fierz term toã. Moreover, it appears that the sensitivity factors for the measurement ofã in 6 He and of P F /P GT in 10 C and 14 O are the same within 2% [2]. Therefore the ratio between the bounds on Re(C T + C T )/C A is provided directly by the ratio between the relative uncertainties of the experimental results.…”

Limits on tensor coupling from neutronβdecay

“…The standard model electroweak radiative corrections are denoted by ∆ RC = 3.90(8) × 10 −2 [7]. G F is the Fermi coupling constant as extracted from muon decay [8], and V ud is the first element of the Cabibbo-Kobyashi-Maskawa (CKM) quark mixing matrix. One can also predict the neutron decay rate from 0 + → 0 + decays, by using the extracted value ofG V from the average Ft 0 + →0 + and λ from neutron angular correlation measurements, where if the Fierz term is zeroG 2 V = G 2…”

New precision measurements of free neutron beta decay with cold neutrons

“…Precision measurements in neutron beta decay belong in the latter category, and seek to illuminate questions related to the number of quark generations (through exploring quark-lepton universality via the Cabibbo-KobayashiMaskawa, or CKM matrix), non-SM forms of weak interaction (i.e., scalar, pseudoscalar and tensor), as well as trace evidence of supersymmetry. The redundancy inherent in the SM description of the neutron beta decay process allows uniquely sensitive checks of the model's validity and limits [1][2][3][4][5][6][7], with strong implications in astrophysics [8].…”