91 research outputs found
Fitting DVCS at NLO and beyond
We outline the twist-two analysis of deeply virtual Compton scattering
(DVCS)within the conformal partial wave expansion of the amplitude, represented
as a Mellin--Barnes integral. The complete next-to-leading order results,
including evolution, are obtained in the MS and a conformal factorization
scheme. Within the latter, exploiting conformal symmetry, the radiative
corrections are evaluated up to next-to-next-to-leading order. Using a new
proposed parameterization for GPDs, we study the convergence of perturbation
theory and demonstrate for H1 and ZEUS measurements that our formalism is
suitable for a fitting procedure of DVCS observables. We comment on a recent
claim of a breakdown of collinear factorization and show that a Regge-inspired
Q^2 scaling law is ruled out by small x_Bj DVCS data.Comment: 15 pages, 4 figure
K -> pi gamma decays and space-time noncommutativity
We propose the K -> pi gamma decay mode as a signature of the violation of
the Lorentz invariance and the appearance of new physics via space-time
noncommutativity.Comment: 3 pages, 1 figure included, version to appear in Phys. Rev.
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