Analysis of the radiativeΛb→Λγtransition in the standard model and scenarios with one or two universal extra dimensions

Abstract

We investigate the radiative process of ${\ensuremath{\Lambda}}_{b}\ensuremath{\rightarrow}\ensuremath{\Lambda}\ensuremath{\gamma}$ in the standard model as well as models with one or two compact universal extra dimensions. Using the form factors entered to the low-energy matrix elements, calculated via light-cone QCD in full theory, we calculate the total decay width and branching ratio of this decay channel. We compare the results of the extra-dimensional models with those of the standard model on the considered physical quantities and look for the deviations of the results from the standard model predictions at different values of the compactification scale ($1/R$).