This 2nd edition is an extensive update of "B Decays?. The revisions are necessary because of the extensive amount of new data and new theoretical ideas. This book reviews what is known about b-quark decays and also looks at what can be learned in the future.The importance of this research area is increasing, as evidenced by the approval of the luminosity upgrade for CESR and the asymmetric B factories at SLAC and KEK, and the possibility of experiments at hadron colliders.The key experimental observations made thus far, measurement of the lifetimes of the different B species, B0-B0 mixing, the discovery of ?Penguin? mediated decays, and the extraction of the CKM matrix elements Vub and Vcb from semileptonic decays, as well as more mundane results, are described in great detail by the experimentalists who have been closely involved with making the measurements. Theoretical progress in understanding b-quark decays using HQET and lattice gauge techniques are described by theorists who have developed and used these techniques.Synthesizing the experimental and theoretical information, several articles discuss the implications for the ?Standard Model? and how further tests can be done using measurements of CP violation in the B system.

From a February 1991 conference in Santa Monica, California, 22 papers by particle, theoretical, and accelerator physicists discuss flavor physics and novel flavor factories (aspects of the subatomic world). CP violation and the search for flavor-changing weak neutral currents are covered extensivel

The authors have studied the B{sup ±} → J/[psi][pi]{sup ±} and B{sup ±} → J/[psi]K{sup ±} decays using a 20.7 fb−1 data set collected with the BABAR detector. They observe a signal of 51 ± 10 B{sup ±} → J/[psi][pi]{sup ±} events and determine the ratio [Beta]({sup {+-}} → J/[psi][pi]{sup {+-}})/[Beta](B{sup {+-}} → J/[psi]K{sup {+-}}) to be [3.91 {+-} 0.78(stat.) {+-} 0.19(syst.)]%. The CP-violating charge asymmetries for the B{sup {+-}} → J/[psi][pi]{sup {+-}} and B{sup {+-}} → J/[psi]{sup {+-}}K{sup {+-}} decays are determined to be [Alpha]{sub {pi}} = 0.01 {+-} 0.22(stat.) {+-} 0.01(syst.) and [Alpha]{sub K} = 0.003 {+-} 0.030(stat.) {+-} 0.004(syst.).

The Belle II detector is situated at the asymmetric $e^{-}e^{+}$ collider SuperKEKB at KEK in Tsukuba in Japan, which operates with an energy slightly above the mass of the Y(4S) resonance. As a result, pairs of B mesons are predominantly produced. Due to the clean experimental environment, various measurements to test the Standard Model and precisely determine its parameters can be performed. This is e.g. the element $V_{ mathrm{cb}}$ of the CKM matrix among others, where one of the leading systematic uncertainties arises due to decays of the nature $B to D^{**} ell nu_{ ell}$ . This th...