We present CDF results on the branching fractions and time-integrated direct CP asymmetries for Bd, Bs and Lb decay modes into pairs of charmless charged hadrons (pions, kaons and protons). The data-set for these measurements amounts to 1fb−1 of p{bar p} collisions at a center of mass energy 1.96TeV. We report on the first observation of the Bs->Kpi, Lb-ppi and Lb->pK decay modes and on the measurement of their branching fractions and direct CP asymmetries.

This work of thesis will investigate the heavy flavor sector, involving decays of particles containing the most massive quarks. In particular, we will study the bhadrons, that means particles containing b-quarks. The topic of this work is the measurements of B and CP asymmetries of two-body charmless decays of neutral b-hadrons, (B0 (s) → h+h' - and [Lambda]0 b →and ph -, where the h can be a pion or a kaon) collectively called B → h+h' -. Next sections describe the theoretical framework in which the b-hadrons are included. Firstly, it is necessary to introduce the CKM matrix describing the electroweak interactions between quarks and how the phenomenon of the CP violation manifests itself.

The CDF experiment at the Tevatron p{bar p} collider established that extensive and detailed exploration of the b-quark dynamics is possible in hadron collisions, with results competitive and supplementary to those from ee− colliders. This provides a rich, and highly rewarding program that has currently reached full maturity. In the following I report some recent results on hadronic decays: the evidence for the charmless annihilation decay mode B{sub s}° →?+?−, and the first reconstruction in hadron collisions of the suppressed decays B− → D(→ K+?°)K− and B− → D(→ K+?−)?−.

The authors report on the charmless B decays measurements performed on 180 pb{sup -1} of data collected with the CDF II detector at the Fermilab Tevatron collider. This paper describes: the first observation of the decay mode B{sub s} {yields} K{sup +}K{sup -} and the measurement of the direct Cp asymmetry in the ({bar B}){sub d} {yields} K{sup {+-}}{pi}{sup {-+}} decay; the first evidence of the decay mode B{sub s} {yields} {phi}{phi} and the branching ratio and Cp asymmetry for the B{sup {+-}} {yields} {phi}K{sup {+-}} decay.

This book highlights two essential analyses of data collected during the LHCb experiment, based on the Large Hadron Collider at CERN. The first comprises the first observation and studies of matter-antimatter asymmetries in two three-body b-baryon decays, paving the way for more precise measurements of the relatively unknown decay properties of b-baryon decays. The second is an analysis of a charged B meson decay to three charged pions, where previously large matter-antimatter asymmetries were observed in a model-independent analysis. Here a model of the decay amplitude is constructed using the unitarity-conserving ‘K-matrix’ model for the scalar contributions, so as to gain an understanding of how the previously observed matter-antimatter asymmetries arise; further, the model’s construction yields the most precise and comprehensive study of this decay mode to date.