Multi-photon signatures at the Fermilab Tevatron

Fermiophobic Higgs bosons (h_f) exhibiting large branching ratios for decay to two photons can arise in models with two or more scalar doublets and/or triplets. In such models the conventional production mechanisms at hadron colliders, which rely on the h_fVV coupling (V=W,Z), may be rendered ineffective due to severe mixing angle suppression. In this scenario, double h_f production may proceed via the complementary mechanism qq’→H^±h_f with subsequent decay H^±→h_fW^*, leading to events with up to four photons. We perform a simulation of the detection prospects of h_f in the multi-photon (>3) channel at the Fermilab Tevatron and show that a sizeable region of the (m_H±,m_hf) parameter space can be probed during Run II.     

Searches for effects of flavor-changing neutral currents

We discuss some possible processes, mainly decays, to search for flavor-changing neutral currents. We examine the theoretical constraints from present data as well as improved sensitivities which might be achieved in future experiments. We focus on the decays K⁰ → μe, Σ⁺ pμe, τ→ μμe and μ → eee as being particularly interesting for further experimental searches.     

Double diffraction dissociation at the Fermilab Tevatron collider

We present results from a measurement of double diffraction dissociation in pp collisions at the Fermilab Tevatron collider. The production cross section for events with a central pseudorapidity gap of width Deltaeta(0)>3 (overlapping eta = 0) is found to be 4.43+/-0.02(stat)+/-1.18(syst) mb [ 3.42+/-0.01(stat)+/-1.09(syst) mb] at square root of (s) = 1800[630] GeV. Our results are compared with previous measurements and with predictions based on Regge theory and factorization.