A review of recent results on branching fractions and time-integrated CP asymmetries of rare B{sub u} and B{sub d} decays to mesonic final states from BABAR Belle and CLEO experiments is presented.

Rare hadronic B-meson decays allow us to study CP violation. The class of B-decays final states containing two vector mesons provides a rich set of angular correlation observables to study. This article reviews some of the recent experimental results from the BABAR and Belle collaborations.

We present results from BaBar experiment for the measurement of inclusive and exclusive branching fractions of B mesons into final states containing J/[psi], [psi](2S) and [chi]c. The contributions of CP even and odd amplitudes in the decay B° 2!J/[psi]K*° are determined from an angular analysis. We report the measurements of the branching ratios B° 2!D* D*− and D* D*− K{sub S}°, and the study of exclusive two-body and quasi-two-body charmless decays. The branching fraction of the decay B° 2!K*°[gamma] has been determined and the corresponding CP asymmetry has been measured.

The PEP-II and KEK asymmetric B factories are providing the BaBar and BELLE collaborations large samples of B mesons, enabling high-statistics searches for rare B decays. The rates for some of these decays can be enhanced by contributions from new physics, while others can provide constraints on the Unitarity Triangle. The author reviews a variety of recent results on rare B decays from these two experiments.

"We present two analyses of the rare B- -> Lambda pbar nu nubar decay. Within the Standard Model, the process B- -> Lambda pbar nu nubar is permitted but highly suppressed, with an expected branching fraction of (7.9 +/- 1.9) x 10^-7. This rarity makes it a sensitive probe for the existence of new physics, which may be discoverable in the form of a higher than predicted branching fraction.The first analysis is conducted on data collected at the BABAR experiment, which ran from 1999-2008. BABAR collected 433 fb^-1 of integrated luminosity at the Upsilon(4S) resonance; Upsilon(4S) decays almost exclusively into B-Bbar pairs, and this analysis uses hadronic tag reconstruction to fully reconstruct one of the B-mesons in this pair. The search for B- -> Lambda pbar nu nubar is then conducted among the decay products of the second, unreconstructed B-meson. Using both real data and Monte Carlo simulations, we develop and implement a signal selection that selects candidates conforming to the expected characteristics of B- -> Lambda pbar nu nubar decays. The result of the analysis is an upper limit on the branching fraction at the 90% confidence level of 3.02 x 10^-5. This is the world's first experimental result in the search for B- -> Lambda pbar nu nubar decays.The second analysis is conducted on Monte Carlo simulations of data that will be collected at Belle II, the world's only next-generation B-meson facility. Over its lifetime Belle II will collect 50 ab^-1 of data, approximately 100 times that of BABAR. This increase in data, along with more capable hardware and software, should allow Belle II to search for B- -> Lambda pbar nu nubar decays with greater sensitivity than BABAR. Using a simulated dataset equivalent in size to that used in our BABAR study, we employ Full Event Interpretation to fully reconstruct the decay of one B-meson in each B-Bbar pair, and conduct our signal selection in the remainder of the data. The result of the analysis is a predicted upper limit on the branching fraction at the 90% confidence level of 1.2 x 10^-4. A comparison of the Belle II and BABAR results highlights several areas where Belle II will need to improve in order to make best use of its projected dataset"--

A selection of rare decay results from BaBar are presented, from a data sample of 82 fb{sup -1} of data taken at the {Upsilon}(4S) resonance (corresponding to 88 x 10{sup 6} B{bar B} pairs).