$H_{u,d}$-messenger Couplings Address the $μ/B_μ$ \& $A_t/m_{H_u}^2$ Problem and $(g-2)_μ$ Puzzle

Abstract

Gauge mediated supersymmetry (SUSY)-breaking (GMSB) furnishes the best idea to overcome the flavor problem in SSMs, supersymmetric stand models (SM). However, implemented in the minimal SSM (MSSM), a very serious fine-tuning problem arises, owing to the absence of a large $A_t$ term in the stop sector to radiatively enhance the SM-like Higgs boson mass. In the extended GMSB coupling $H_u$ to messengers can alleviate this problem but encounters the $A_t/m_{H_u}^2$ problem, i.e., at the same time a large $m_{H_u}^2$ is generated, rendering radiative electroweak spontaneously breaking (EWSB) problematic. This issue shows similarity to another long-standing problem of GMSB, the $μ/{B_μ}$ problem, and, of great interest, we find that they may admit the same solution, nonradiative EWSB. Such a solution is naturally accommodated when both $H_u$ and $H_d$ couple to messengers. As a bonus of nonradiative EWSB, the sleptons tend to be very light due to the significant renormalization group equation effect and they are able to account for the $(g-2)_μ$ puzzle. As a concrete example, we investigate a hidden sector with $(10,\overline {10})$ messengers.