This document presents results of the search for B + → etaXK+ in which etaX → etapi+pi - or etaX → K0S K+pi-, and etaX is a potentially exotic state with a resonant mass within (1.2-1.8) GeV. We use the BABAR data of 382.9 million BB pairs and report the first observation of B+ → eta(1295) K+ and B+ → eta(1475)K+, and set upper limits for the modes listed below. We also consider an alternative signal model in the etaX → K0S K+/-pi∓ mode with an extra resonance, to better describe the meson mass spectrum. We provide the central values where possible. Hermitian conjugation is implied throughout the document unless stated otherwise. BB+/- →h1295 K+/- xBh 1295→h pp=2.93+0.77+0.22 -0.73-0.21 ˙10-6, BB+/- →h1475 K+/- xBh 1475→ KK&d1;p =13.79+1.83+1.00-1.65-0.56 ˙10-6. The following upper limits assume 90% C.L: BB+/- →f11285 K+/-xB f11285 →hpp

This thesis describes a high-quality, high-precision method for the data analysis of an interesting elementary particle reaction. The data was collected at the Japanese B-meson factory KEKB with the Belle detector, one of the most successful large-scale experiments worldwide. CP violation is a subtle quantum effect that makes the world look different when simultaneously left and right and matter and antimatter are exchanged. This being a prerequisite for our own world to have developed from the big bang, there are only a few experimental indications of such effects, and their detection requires very intricate techniques. The discovery of CP violation in B meson decays garnered Kobayashi and Maskawa, who had predicted these findings as early as 1973, the 2008 Nobel prize in physics. This thesis describes in great detail what are by far the best measurements of branching ratios and CP violation parameters in two special reactions with two charm mesons in the final state. It presents an in-depth but accessible overview of the theory, phenomenology, experimental setup, data collection, Monte Carlo simulations, (blind) statistical data analysis, and systematic uncertainty studies.

The authors present measurements of branching fractions and CP-violating asymmetries in decays of B mesons to two-body final states containing a K[sup 0]. The results are based on a data sample of approximately 88 million [Upsilon](4S) [yields] B[bar B] decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC.

We present recent results on time integrated and time dependent CP violation for charmless hadronic B decays using BABAR detector at the PEP-II B-factory.