ar X iv : h ep - p h / 99 05 43 1 v 1 2 1 M ay 1 99 9 The lowest - order short - distance contribution to the B s → γγ decay Gela

ar X iv : h ep - p h / 99 05 50 4 v 1 2 7 M ay 1 99 9 On the Long Distance Contribution to the B s → γγ Decay in the Effective Lagrangian Approach

We re-estimate the decay branching ratio of Bs → 2γ through D + s D − s and D∗+ s D ∗− s intermediate states, in the effective Lagrangian approach. We find that the branching ratio does not exceed a few times 10−7, contrary to the result recently claimed in the literature. PACS numbers: 13.25.Hw Typeset using REVTEX

ar X iv : h ep - p h / 96 05 31 0 v 1 1 5 M ay 1 99 6 O ( α 2 G F m 2 t ) Contributions to H → γγ

The rare decay H → γγ is a promising detection channel for an intermediate mass Higgs boson. We compute its two-loop O(αGFm 2 t ) correction in the standard model and find that it is much smaller than the corresponding QCD correction. The analogous correction to the amplitude for gg → H is recovered as a special case. The generalization of our result to other models is also briefly indicated.

ar X iv : h ep - t h / 96 05 13 9 v 1 2 1 M ay 1 99 6 Differential Renormalization of QCD in the Background - Field Method

A short outline is given on the application of differential regularization to QCD in the background-field method. The derivation of the propagators in the background gluon field as short-distance expansions is described and the renormalization of the theory is mentioned.

ar X iv : h ep - p h / 99 05 46 9 v 1 2 5 M ay 1 99 9 DESY 99 – 060 hep - ph / 9905469 May 1999 W Boson Production at NLO ∗

We discuss W boson production at HERA including NLO QCD corrections. A detailed comparison with previous work is presented.

ar X iv : h ep - p h / 98 05 30 4 v 1 1 3 M ay 1 99 8 Λ b → Λ c P ( V ) Nonleptonic Weak Decays