Charm Physics at CDF II

The CDF II detector has the capability of triggering on displaced tracks. Because of this ability, CDF II has accrued large samples of charmed meson decays to fully hadronic final states in 64 pb^-1 of ppbar collision data gathered at sqrt(s) = 1.96 TeV. Using initial Run II data samples, the production cross sections for J/psi, D0, D+, D*+ and Ds+ mesons have been measured. Ratios of branching ratios for Cabibbo suppressed final states and CP asymmetries in D0 meson decays have been studied. A measurement of the mass difference m(Ds+) - m(D+) has been done, and a limit for the branching fraction of the FCNC D0 -> mu+ mu- decays has been set.Comment: Presented at 17th Les Rencontres de Physique de la Vallee d'Aoste: Results and Perspectives in Particle Physics, La Thuile, Aosta Valley, Italy, 9-15 Mar 200

NMSSM with Lopsided Gauge Mediation

We study a gauge mediated supersymmetry breaking version of the NMSSM in which the soft m_{H_u}^2 and m_{H_d}^2 masses receive extra contributions due to the presence of direct couplings between the Higgs and the messenger sector. We are motivated by the well-known result that minimal gauge mediation is phenomenologically incompatible with the NMSSM due to the small value of the induced effective mu term. The model considered in the present paper solves the aforementioned problem through a modified RG running of the singlet soft mass m_N^2. This effect, which is induced by the dominant m_{H_d}^2 term in the one-loop beta-function of m_N^2, shifts the singlet soft mass towards large negative values at the electroweak scale. That is sufficient to ensure a large VEV for the scalar component of the singlet which in turn translates into a sizeable effective mu term. We also describe a mechanism for generating large soft trilinear terms at the messenger scale. This allows us to make the mass of the lightest Higgs boson compatible with the current LHC bound without relying on exceedingly heavy stops