Beyond the Dark matter effective field theory and a simplified model approach at colliders

Direct detection of and LHC search for the singlet fermion dark matter (SFDM) model with Higgs portal interaction are considered in a renormalizable model where the full Standard Model (SM) gauge symmetry is imposed by introducing a singlet scalar messenger. In this model, direct detection is described by an effective operator m_q \bar{q} q \bar{\chi} \chi as usual, but the full amplitude for monojet + \not E_T involves two intermediate scalar propagators, which cannot be seen within the effective field theory (EFT) or in the simplified model without the full SM gauge symmetry. We derive the collider bounds from the ATLAS monojet + \not E_T as well as the CMS t\bar{t} + \not E_T data, finding out that the bounds and the interpretation of the results are completely different from those obtained within the EFT or simplified models. It is pointed out that it is important to respect unitarity, renormalizability and local gauge invariance of the SM.Comment: 7 pages, 3 figures, version published in Phys. Lett.

Implications of the measurements of B_s - B_s bar mixing on SUSY models

We derive constraints on the mass insertion parameters from the recent measurements of B_s - B_s bar mixing, and discuss their implications on SUSY breaking mediation mechanisms and SUSY flavor models. Some SUSY flavor models are already excluded or disfavored by B_s - B_s bar mixing. We also discuss how to test the SM and SUSY models in the future experiments, by studying other CP violating observables related to b -> s transition, such as the time-dependent CP asymmetry in B -> phi K_S and the direct CP asymmetry in B -> X_s gamma.Comment: 29 page

Sflavor mixing map viewed from a high scale in supersymmetric SU(5)

We study flavor violation in a supersymmetric SU(5) grand unification scenario in a model-independent way employing mass insertions. We examine how the quark and the lepton sector observables restrict sfermion mixings. With a low soft scalar mass, a lepton flavor violating process provides a stringent constraint on the flavor structure of right-handed down-type squarks. In particular, mu -> e gamma turns out to be highly susceptible to the 1-3 and 2-3 mixings thereof, due to the radiative correction from the top Yukawa coupling to the scalar mass terms of 10. With a higher scalar mass around the optimal value, in contrast, the quark sector inputs such as B-meson mixings and hadron electric dipole moment, essentially determine the room for sfermion mixing. We also discuss the recent deviation observed in B_s mixing phase, projected sensitivity of forthcoming experiments, and ways to maintain the power of leptonic restrictions even after incorporating a solution to fix the incorrect quark-lepton mass relations.Comment: 40 pages, updated using phi_s from HFAG, conclusion unchange

B0 - B0 bar mixing, B -> J/psi K_S and B -> X_d gamma in general MSSM

We consider the gluino-mediated SUSY contributions to B0 - B0 bar mixing, B -> J/psi K_S and B -> X_d gamma in the mass insertion approximation. We find the LL mixing parameter can be as large as |delta_{13}^d_{LL}| < 2*10^-1, but the LR mixing is strongly constrained by the B -> X_d gamma branching ratio and we find |delta_{13}^d_{LR}| < 10^-2. The implications for the direct CP asymmetry in B -> X_d gamma and the dilepton charge asymmetry (A_{ll}) are also discussed, where substantial deviations from the standard model predictions are possible.Comment: 14 pages, 4 figure