b-physics signals of the lightest CP-odd Higgs in the NMSSM at large tanβ

We investigate the low energy phenomenology of the lighter pseudoscalar A1 in the NMSSM. The A1 mass can naturally be small due to a global U(1)R symmetry of the Higgs potential, which is only broken by trilinear soft terms. The A1 mass is further protected from renormalization group effects in the large tan β limit. We calculate the b → sA1 amplitude at leading order in tan β and work out the contributions to rare K, B and radiative Υ-decays and B − B̄ mixing. We obtain constraints on the A1 mass and couplings and show that masses down to O(10) MeV are allowed. The b-physics phenomenology of the NMSSM differs from the MSSM in the appearance of sizeable renormalization effects from neutral Higgses to the photon and gluon dipole operators and the breakdown of the MSSM correlation between the Bs → μ+μ− branching ratio and Bs − B̄s mixing. For A1 masses above the tau threshold the A1 can be searched for in b → sτ+τ− processes with branching ratios < ∼ 10 −3. email: [email protected]