Malcolm John

Abstract:

A measurement of the time-dependent CP asymmetry for the neutral B-meson decay B0 → φK0 was discussed. The study was carried by using a sample of B-meson pairs taken at the γ(4S) resonance with the BABAR detector at the PEP-II B-meson factory at SLAC. The CP eigenstates were reconstructed φK0s and φK 0L, where φ K+K-,K 0s → π+ π-, and K 0L was observed. The results show that the values of the CP-violations parameters were SφK = 0.47 ± 0.37(stat) +0.08-0.06.

Abstract:

The branching fraction for the semi-inclusive process B→ήXs, where Xs is a strange hadronic system, was measured. The Xs mass spectrum was also obtained, which fits into models predicting high masses. Two tracking devices, a silicon vertex tracker consisting of five layers of double-sided silicon microstrip detectors and a 40-layer central drift chamber, were used for the detection of charged particles. It was found that the charged-particle identification was provided by the average energy loss in the tracking devices.

Abstract:

The branching fractions and charge asymmeteries in B-meson decays were discussed. The decay amplitudes were evaluated from the measurements of decay rates and CP-violating charge asymmetries. The B-background from charmed and charmless B decays was investigated using MC-simulated events. The uncertainties in the signal MC simulation, which include signal misreconstruction, were evaluated from fully reconstructed B-decays. The misreconstruction signal was due the presence of low momentum pions in the B-decays.

Abstract:

The observation of charmonium production in B meson decays by color-supressed b → cc̄s quark transition was discussed. The data used in the observation correspond to a integrated luminosity of 81.9 fb -1 taken on the γ(4S) resonance. The data were collected at the asymmetric energy e+e- storage ring with BABAR detectors. The results show that with an upper limit of X(3872) in the product branching fraction the magnitude of possibole enhancements with charmonium hybrid states can restrict.

Abstract:

A measurement of the direct CP asymmetry between inclusive b→sγ decays was performed. It was observed that this asymmetry was expected to be less than 0.01 in the standard model but could be enhanced up to 0.10. The different components of the signal and background events was also identified that was described by a crystal ball function. Monte Carlo simulations were also applied to the four contributions to the beam energy substituted mass distribution of events.