Abstract: (arXiv)
In the Minimal Supersymmetric Standard Model (MSSM), large chiral symmetry breaking term AtA_t, which plays an important role in Higgs mass, may significantly contribute in flavor changing neutral current (FCNC) processes BXsγB\to X_{s}\gamma and Bsμ+μB_{s}\to \mu^{+}\mu^{-}. Though the above processes can both be categorized as bsb\to s transitions, the two rare decays behave completely different in MSSM. With an on-shell photon in the final state, helicity of initial state bb-quark and final state ss-quark must be flipped in BXsγB\to X_{s}\gamma, which corresponds to the simultaneous breaking of chiral symmetry and electroweak symmetry. The common feature is shared by fermion mass generation. Same as radiative mass generation in MSSM, Peccei-Quinn and RR symmetry breaking contributions, for example from a Higgsino-stop loop when μAt<0\mu A_t<0, may significantly cancel the contribution from charged Higgs and reduce the prediction of BXsγB\to X_{s}\gamma. For the latter process, including Babu-Kolda FCNC proportional to μAt\mu A_t, Bsμ+μB_{s}\to \mu^{+}\mu^{-} is mediated by a scalar HdH_d boson which corresponds to chiral symmetry breaking. In addition, as a result of interference among the Higgs extension sector and ZZ contributions, in the region of μAt<0\mu A_t <0 which is favored by BXsγB\to X_{s}\gamma, there may simultaneously exist large enhancement in Bsμ+μB_{s}\to \mu^{+}\mu^{-}. However, we still find viable parameter region with light Higgsino of a few hundreds GeV when charged Higgs contribution is not negligible with MAM_A of 400 GeV.
Note:
  • 15 pages, 6 figures
  • new physics
  • supersymmetry
  • minimal supersymmetric standard model: parameter space
  • stop: mixing
  • stop: coupling
  • coupling: Higgs
  • Higgsino: mass
  • Higgsino: exchange
  • B: rare decay
  • B: radiative decay