Phenomenological Studies Of New Physics Effects In (?)?X_c?(?)_? Decay

The Standard Model of particle physics describes the three fundamental interactions in nature except for the gravitational one:strong,weak and electromagnetic interactions.Most of the predictions of the Standard Model have been verified by experiments,and have achieved a high accuracy.So,the Standard Model is considered to be one of the most successful theories in history.However,there are still a few flaws in the Standard Model;for example,there eixsts a large diviation between the theoretical predictions and the experimental measurements for some physical observables(such as R(D(*)discussed in this thesis),which provides space for the existence of New Physics beyond the Standard Model.Heavy flavor physics,especially B-meson physics,has always been a frontier field of particle physics.Among them,the B-meson decay is regarded as an important place to accurately test the Standard Model,to measure its related parameters and to explore New Physics.In this thesis,we explore the inclusive semileptonic B-meson decay B ?XcTVT both within the Standard Model and in a model-independent New Physics framework.In chapter 2,we briefly introduce the Standard Model and the theoretical tools needed to study the B-meson weak decays,including the operator product expansion,the heavy-quark effective theory and so on.In chapter 3,we first discuss the inclusive semileptonic B-meson decay within the Standard Model and calculate its decay width,including the contributions of power corrections up to order 1/mb3 and the one-loop(?)(?s)QCD correction.Then,we study the effects of various model-independent New Physics operators on this decay,in which the effect of power correction is also taken into account,and the allowed parameter space of New Physics operators are obtained under the experimental constraints of R(D(*)).Finally,in the dicussed New Physics framework and using the allowed parameter space,we present our predictions for the ratio of the braching fractions(?)and the differential decay rate(?)Thechapter 4 contains our summary and prospect.Our results of the decay B? XcTVT obtained in this paper will further deepen our understanding of various New Physics models used to explain the R(D(*)anomalies and,at the same time,motivate the accurate experimental measurements of the physical observables predicted in this paper.