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Giulia Ricciardi

Publications and source records attributed to Giulia Ricciardi.

60 records · Page 4Linked to original sources
arXiv1997

QCD corrections to b -> s gamma gamma induced decays: B -> X_s gamma gamma and B_s -> gamma gamma

We present a complete calculation of the Leading Order QCD corrections to the quark level decay amplitude for b -> s gamma gamma and study their relevance for both the inclusive branching ratio BR(B -> X_s gamma gamma) and for the exclusive decay channel B_s -> gamma gamma. In addition to the uncertainties in the short distance calculation, due to the choice of the renormalization scale, an appreciable uncertainty in both B_s -> gamma gamma and B -> X_s gamma gamma is introduced by the matrix element calculation. We also briefly discuss some long distance effects, especially those due to the eta_c resonance for the inclusive rate. Finally, the analysis of the IR singularities of the two photon spectrum in the inclusive case is given.

hep-ph↗
arXiv1996

The B -> X_s gamma gamma rare decay

The rare decay B -> X_s gamma gamma is studied in the Standard Model (SM) and in two different versions (Model I and Model II) of the Two Higgs Doublet Model (2HDM). In the SM the branching ratio into ``hard photons'' is about 10^(-7) and can be appreciably different in the 2HDM. We also introduce a forward-backward asymmetry which gives an additional handle to discriminate different models.

hep-ph↗
arXiv1995

Theoretical Review of Radiative Rare B Decays

A status report on the theory of radiative rare $B$ decays in the standard model is presented, with focus on inclusive decays $B \rightarrow X_{(s,d)}\, γ$ and exclusive decays $B \rightarrow (K^\ast,ω,ρ) \, γ$. CP asymmetries are also briefly discussed.

hep-ph↗
arXiv1995

Short and Long Distance Interplay in Inclusive $ B \to X_d γ$ Decays

We analyze the short and long distance contributions to inclusive $B \rightarrow X_d γ$ decay, paying particular attention to the dependence on the Cabibbo-Kobayashi-Maskawa parameter $V_{td}$. We discuss penguin diagrams with internal $u$ and $c$ quarks in the framework of the effective field theory. We also estimate the size of possible long range contributions by using vector meson dominance.

hep-ph↗
arXiv1994

QCD corrections to electroweak processes in an unconventional scheme: application to the b -> s gamma decay

In this work we give a detailed description of a method for the calculation of QCD corrections to electroweak processes in dimensional regularization that does not require any definition of the gamma_5 matrix in d dimensions. This method appears particularly convenient in order to limit the algebraic complexity of higher order calculations. As an example, we compute the leading logarithmic corrections to the b -> s gamma decay.

hep-ph↗