Yu Muramatsu

Two-loop renormalization factors of dimension-six proton decay operators in the supersymmetric standard models

Abstract The renormalization factors of the dimension-six effective operators for proton decay are evaluated at two-loop level in the supersymmetric grand unified theories. For this purpose, we use the previous results in which the quantum corrections to the effective Kahler potential are evaluated at two-loop level. Numerical values for the factors are presented in the case of the minimal supersymmetric SU(5) grand unified model. We also derive a simple formula for the one-loop renormalization factors for any higher-dimensional operators in the Kahler potential, assuming that they are induced by the gauge interactions.

Flavor violating Z′ from SO(10) SUSY GUT in High-Scale SUSY

Abstract We propose an SO ( 10 ) supersymmetric grand unified theory (SUSY GUT), where the SO ( 10 ) gauge symmetry breaks down to SU ( 3 ) c × SU ( 2 ) L × U ( 1 ) Y × U ( 1 ) X at the GUT scale and U ( 1 ) X is radiatively broken at the SUSY-braking scale. In order to achieve the observed Higgs mass around 126 GeV and also to satisfy constraints on flavor- and/or CP-violating processes, we assume that the SUSY-breaking scale is O ( 100 ) TeV , so that the U ( 1 ) X breaking scale is also O ( 100 ) TeV . One big issue in the SO ( 10 ) GUTs is how to realize realistic Yukawa couplings. In our model, not only 16-dimensional but also 10-dimensional matter fields are introduced to predict the observed fermion masses and mixings. The Standard-Model quarks and leptons are linear combinations of the 16- and 10-dimensional fields so that the U ( 1 ) X gauge interaction may be flavor-violating. We investigate the current constraints on the flavor-violating Z ′ interaction from the flavor physics and discuss prospects for future experiments.

Flavor physics induced by light

A bstractIn this paper, we investigate predictions of the SO(10) Grand Unified Theory (GUT), where an extra U(1)′ gauge symmetry remains up to the supersymmetry (SUSY) breaking scale. The minimal setup of SO(10) GUT unifies quarks and leptons into a 16-representational field in each generations. The setup, however, suffers from the realization of the realistic Yukawa couplings at the electroweak scale. In order to solve this problem, we introduce 10-representational matter fields, and then the two kinds of matter fields mix with each other at the SUSY breaking scale, where the extra U(1)′ gauge symmetry breaks down radiatively. One crucial prediction is that the Standard Model quarks and leptons are given by the linear combinations of the fields with two different U(1)′ charges. The mixing also depends on the flavor. Consequently, the U(1)′ interaction becomes flavor violating, and the flavor physics is the smoking-gun signal of our GUT model. The flavor violating Z′ couplings are related to the fermion masses and the CKM matrix, so that we can derive some explicit predictions in flavor physics. We especially discuss K-K¯

from SO(10) GUT

\overline{K}

U(1)_A

mixing, B(s)-Bs¯

Flavor changing nucleon decay

\overline{B_{(s)}}