2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/48758Physics beyond the Standard Model could be measured indirectly, through its effects on Standard Model observables. One place to look for such effects is in the semileptonic decays of B mesons. In order to constrain the possible role of new physics on semileptonic B decays, we present the most general low energy effective Lagrangian constructed from all dimension six four-fermion operators that contribute to the process b-> c l- nu. We then use it to compute the corrections due to new physics to the differential decay rates for the exclusive processes B-> D(*) l- nu, as well as the inclusive decays B-> X l- nu. Both inclusive and exclusive rates are expressed in terms of a set of parameters that characterize the types of four-fermion interactions that can be induced by physics beyond the Standard Model. Although it is not particularly useful to carry out a full analysis until data from the next generation of B factories becomes available, here we illustrate how the existing experimental results can be used to constrain some of these parameters.16 pages, LatexHigh Energy Physics - Phenomenologytext