In this Snowmass whitepaper, we describe the impact of ongoing and proposed intensity frontier experiments on the parameter space of the Minimally Supersymmetric Standard Model (MSSM). We extend a set of phenomenological MSSM (pMSSM) models to includ
e non-zero CP-violating phases and study the sensitivity of various flavor observables in these scenarios Future electric dipole moment and rare meson decay experiments can have a strong impact on the viability of these models that is relatively independent of the detailed superpartner spectrum. In particular, we find that these experiments have the potential to probe models that are expected to escape searches at the high-luminosity LHC.
We point out that, if the direct CP asymmetries in the $D to pi^+ pi^-$ and $D to K^+ K^-$ decays are unequal, the indirect CP asymmetries as measured in these modes are necessarily unequal. This nonuniversality of indirect CP asymmetries can be sign
ificant with the right amount of new physics contributions, a scenario that may be fine-tuned, but is still viable. A model-independent fit to the current data allows different indirect CP asymmetries in the above two decays. This could even be contributing to the apparent tension between the difference CP asymmetries $Delta A_{rm CP}$ measured through the pion-tagged and muon-tagged data samples at the LHCb. This also implies that the measurements of $A_Gamma$ and $y_{rm CP}$ in the $pi^+ pi^-$ and $K^+ K^-$ decay modes can be different, and averaging over these two modes should be avoided. In any case, the complete analysis of CP violation measurements in the $D$ meson sector needs to take into account the possibility of different indirect CP asymmetries in the $pi^+pi^-$ and $K^+ K^-$ channels.
The recent Belle and BaBar measurements of the branching ratio of $B^+ to tau^+ u_tau$ indicate a significant deviation from the Standard Model prediction. We demonstrate that this measurement has a serious impact on models with minimal flavor viola
tion involving a charged Higgs boson, ruling out a large portion of the currently-allowed parameter space. In the constrained minimal supersymmetric standard model, this creates a tension between the measurements of $B^+ to tau^+ u_tau$ and the anomalous magnetic moment of the muon, unless $tanbeta$ is small, $mu > 0$, and $A_0$ takes a large negative value. In fact, a very small region of the parameter space of this model, with small values of $m_0$ and $m_{1/2}$, survives all the constraints at 95% C.L.. It is remarkable that this specific region is still consistent with the lightest supersymmetric particle as the dark matter. Moreover, it predicts observable SUSY signals in the early runs of the LHC, even perhaps at 7 TeV. We also show that a consistent explanation for the deviation of the $B^+ to tau^+ u_tau$ branching ratio from the Standard Model can be achieved in a non-universal Higgs mass model, which could also predict early signals of supersymmetry at the LHC.
