Download Free Measurement Of The Branching Fraction And Search For Direct Cp Violation In The Radiative Decay B To Kgamma With The Babar Detector Book in PDF and EPUB Free Download. You can read online Measurement Of The Branching Fraction And Search For Direct Cp Violation In The Radiative Decay B To Kgamma With The Babar Detector and write the review.

The presented study of the radiative electroweak "penguin"--Decay B->K*(892)gamma, proceeding by the b->sgamma "loop"-transition, provides an important test of the Standard Model and a candidate of the search for New Physics. The used data sample has been recorded at the Y(4S) resonance with the BABAR detector at the asymmetric electron-positron- collider PEP-II of the Stanford Linear Accelerator Center (SLAC) in California. The B->K*gamma branching fractions are measured in four K*-decay modes. A search for direct CP-violation in the B->K*gamma mode has also been carried out.
The phenomenon of CP-violation in weak interactions, discovered in 1964 in decays of neutral kaons, receives a simple and elegant explanation in the Standard Model with three generations of quarks. Indeed, in this model the common source of CP-asymmetry phenomena is represented by a simple complex phase in the unitary matrix (the Cabibbo-Kobayashi-Maskawa matrix) describing the charged weak couplings of the quarks. This simple scheme has never received an accurate validation, because the phenomenological parameters determined from measurements of CP-violation in kaons decays are related to the fundamental parameters of the theory in a complex way, sensitive to large theoretical uncertainties. On the contrary, decays of neutral B mesons like B{sup 0} {yields} J/{psi} K{sub S}{sup 0} represent a unique laboratory to test the predictions of the theory because they are expected to show significant CP-violation effects, the magnitude of which is cleanly related to the Standard Model parameters. Thus experimental facilities have been built with the purpose of performing extensive studies of B decays. The BABAR experiment is operating at one of these facilities, at the Stanford Linear Accelerator Center. It is collecting data at the PEP-II asymmetric e{sup +}e{sup -} collider (E{sub e{sup -}} = 9.0 GeV; E{sub e{sup +}} = 3.1 GeV), a high-luminosity accelerator machine (L = 3 x 10{sup 33} cm{sup -2}s{sup -1}). The center-of-mass energy (10.58 GeV) of the e{sup +}e{sup -} system at PEP-II allows resonant production of the {Upsilon}(4S), a b{bar b} bound state, which decays almost exclusively in a B{sup 0}{bar B}{sup 0} or a B{sup +}B{sup -} pair. A high-acceptance detector, projected and built by a wide international collaboration, detects and characterizes the decay products of the B mesons. From the analysis of the data collected during the first two years of operation, the BABAR collaboration has established CP-violation in decays of neutral B mesons at the 4.1{sigma} level. Besides the primary goal of CP-violation studies, the high luminosity of PEP-II, coupled with the high acceptance of the BABAR detector, allows competitive studies of the properties of a wide set of B decay modes. In particular, measurements of non-leptonic decays are extremely useful to understand the dynamics of the non-perturbative strong interactions involved in these processes. In this thesis a study of the non-leptonic decay mode B{sup {+-}} {yields} J/{psi}{pi}{sup {+-}} is presented.
The authors present measurements of branching fractions in the b 2!s{bar s}s penguin-dominated decays B 2![phi]K and B° 2![phi]K° in a sample of approximately 89 million B{bar B} pairs collected by the BABAR detector at the PEP-II asymmetric-energy B-meson Factory at SLAC. They determine [Beta](B+ 2![phi]K+) = (10.0{sub -0.8}{sup +0.9} ± 0.5) x 10−6 and [Beta](B° 2![phi]K°) = (8.4{sub -1.3}{sup +1.5} ± 0.5) x 10−6. Additionally, they measure the CP-violating charge asymmetry [Alpha]{sub CP}(B{sup ±} 2![phi]K{sup ±}) = 0.04 {+-} 0.09 {+-} 0.01, with a 90% confidence-level interval of [-0.10, 0.18], and set an upper limit on the CKM- and color-suppressed decay B+ 2![phi][pi]+, [Beta](B+ 2![phi][pi]+)
The primary goals of the BABAR experiment are the detection of CP violation (CPV) in the B meson system, the precise measurement of some of the elements of the CKM matrix and the measurement of the rates of rare B meson decays. At present, BABAR has achieved major successes: (1) the discovery, in neutral B decays, of direct and mixing-induced CP violation; (2) accurate measurements of the magnitudes of the CKM matrix elements.
The authors present measurements of the CP-violation parameters S and C for the radiative decay B° →?K{sub S}°?; for B →?K? they also measure the branching fractions and for B →?K+? the time-integrated charge asymmetry?{sub ch}. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 465 x 106 B{bar B} pairs produced in e+e− annihilation. The results are S = -0.18{sub -0.46}{sup +0.49} ± 0.12, C = -0.32{sub -0.39}{sup +0.40} ± 0.07,?(B° →?K°?) = (7.1{sub -2.0}{sup +2.1} ± 0.4) x 10−6,?(B+ →?K+?) = (7.7 ± 1.0 ± 0.4) x 10−6, and?{sub ch} = ( -9.0{sub -9.8}{sup +10.4} ± 1.4) x 10−2. The first error quoted is statistical and the second systematic.