Download or read book Study of B to X gamma Decays and Determination of written by and published by . This book was released on 2011 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using a sample of 471 million B{bar B} events collected with the BABAR detector, we study the sum of seven exclusive final states B → X{sub s(d)[gamma]}, where X{sub s(d)} is a strange (non-strange) hadronic system with a mass of up to 2.0 GeV/c2. After correcting for unobserved decay modes, we obtain a branching fraction for b → d[gamma] of (9.2 ± 2.0(stat.) ± 2.3(syst.)) x 10−6 in this mass range, and a branching fraction for b → s[gamma] of (23.0 ± 0.8(stat.) ± 3.0(syst.)) x 10−5 in the same mass range. We find [Beta](b→d[gamma])/[Beta](b→s{gamma}) = 0.040 ± 0.009(stat.) ± 0.010(syst.), from which we determine.

Download or read book Measurement of B to X gamma Decays and Determination of written by and published by . This book was released on 2008 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using a sample of 383 million B{bar B} events collected by the BABAR experiment, they measure sums of seven exclusive final states B → X{sub d(s)}[gamma], where X{sub d}(X{sub s}) is a non-strange (strange) charmless hadronic system in the mass range 0.6-1.8 GeV/c2. After correcting for unmeasured decay modes in this mass range, they obtain a branching fraction for b → d[gamma] of (7.2 ± 2.7(stat.) ± 2.3(syst.)) x 10−6. Taking the ratio of X{sub d} to X{sub s} they find [Lambda](b → d[gamma])/[Lambda](b → s[gamma]) = 0.033 ± 0.013(stat.) ± 0.009(syst.), from which they determine.

Download or read book Studying B S Gamma at BABAR Using a Fully Inclusive Method written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The b [yields] s[gamma] decay represents a possible electromagnetic ''loop'' penguin decay of the B meson. This FCNC process is of high theoretical interest because various scenarios of new physics are expected to have contributions at the same (one loop) level as the Standard Model. The large sample of B[bar B] meson decays collected by the BaBar experiment makes a precision measurement of this rare decay possible. In conjunction with Standard Model predictions at the 10% level, it brings new physics effects into the realm of detection--or seriously constrains models that could predict them. A fully inclusive technique is presented to study the b [yields] s[gamma] transition as a function of photon energy, using 88.5 [+-] 1.0 x 10[sup 6] B[bar B] meson decays collected by the BaBar experiment in the years 2000 to 2002. The expected statistical and systematic uncertainties have been fully determined which enables first comparisons with theoretical predictions and other experimental results. It also lays the basis for the determination of the inclusive branching fraction [Beta](B [yields] X[sub s][gamma]) and the measurement of the photon energy spectrum.

Download or read book Measurement of the Branching Fraction and Photon Energy Moments of B to Xs Gamma and A cp B to X s d Gamma written by and published by . This book was released on 2006 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The photon spectrum in B 2!X{sub s}[gamma] decay, where X{sub s} is any strange hadronic state, is studied using a data sample of 88.5 x 106 ee− 2 2!B{bar B} decays collected by the BABAR experiment at SLAC. The partial branching fraction, [Delta][Beta](B 2!X{sub s}[gamma]) = (3.67 ± 0.29(stat.) ± 0.34(sys.) ± 0.29(model)) x 10−4, the first moment E{sub {gamma}} = 2.288 ± 0.025 ± 0.017 ± 0.015 GeV and the second moment E{sub {gamma}}2 = 0.0328 ± 0.0040 ± 0.0023 ± 0.0036 GeV2 are measured for the photon energy range 1.9 GeV E{sub {gamma}}

Download or read book Study of the B to Xclnu Decays and Determination of written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report studies of semileptonic decays, B → X{sub c}l[nu], based on a sample of 88 million B{bar B} events recorded with the BABAR detector. We have measured four moments of the electron energy and hadronic mass distributions and determined the inclusive branching fraction, the CKM matrix element.

Download or read book A Study of B ccbar Gamma K in the BaBar Experiment written by and published by . This book was released on 2010 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: The BABAR Collaboration is a high energy physics experiment located at the Stanford Linear Accelerator Center. The primary goal of the experiment is to study charge and parity violation in the B-meson sector, however the copious production of B mesons decaying to other final states allows for a wide-ranging physics program. In particular, one can access the charmonium system via colour-suppressed b → c decays of the type B → c{bar c}K. This thesis presents a study of B → c{bar c}[gamma]K decays where c{bar c} includes J/[psi] and [psi](2S), and K includes K{sup ±}, K{sub S}° and K*(892). The particular emphasis is on a search for the radiative decays X(3872) → J/[psi][gamma] and X(3872) → [psi](2S)[gamma]. The X(3872) state is a recently-discovered resonance of undetermined quark composition, speculatively a conventional charmonium state or exotic four-quark di-meson molecule. This research is also sensitive to the well-known radiative charmonium decays B → [chi]{sub c1,2}K, which are used as verification for the analysis technique. This dissertation sets the best B → [chi]{sub c1}K branching fraction measurements to date, and sees the first evidence for factorization-suppressed B° → [chi]{sub c2}K*° decay at a level of 3.6[sigma]. It also provides evidence for X(3872) → J/[psi][gamma] and X(3872) → [psi](2S)[gamma] with 3.6[sigma] and 3.3[sigma] significance, respectively. The product of branching fractions [Beta](B{sup ±} → X(3872)K{sup ±}) · [Beta](X(3872) → J/[psi][gamma]) = (2.8 ± 0.8(stat.) {+-} 0.2(syst.)) x 10−6 and [Beta](B{sup {+-}} → X(3872)K{sup {+-}}) → [Beta](X(3872) → [psi](2S)[gamma]) = (9.5 {+-} 2.7(stat.) {+-} 0.9(syst.)) x 10−6 are measured. These results improve upon previous X(3872) → J/[psi][gamma] measurements, and represent the first evidence for X(3872) → [psi](2S)[gamma].

Download or read book Measurement of Inclusive Radiative B Meson Decay B X s Gamma written by and published by . This book was released on 2006 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radiative decays of the B meson, B 2!X{sub s}[gamma], proceed via virtual flavor changing neutral current processes that are sensitive to contributions from high mass scales, either within the Standard Model of electroweak interactions or beyond. In the Standard Model, these transitions are sensitive to the weak interactions of the top quark, and relatively robust predictions of the inclusive decay rate exist. Significant deviation from these predictions could be interpreted as indications for processes not included in the minimal Standard Model, like interactions of charged Higgs or SUSY particles. The analysis of the inclusive photon spectrum from B 2!X{sub s}[gamma] decays is rather challenging due to high backgrounds from photons emitted in the decay of mesons in B decays as well as ee− annihilation to low mass quark and lepton pairs. Based on 88.5 million B{bar B} events collected by the BABAR detector, the photon spectrum above 1.9 GeV is presented. By comparison of the first and second moments of the photon spectrum with QCD predictions (calculated in the kinetic scheme), QCD parameters describing the bound state of the b quark in the B meson are extracted: m{sub b} = (4.45 ± 0.16) GeV/c2; [mu]{sub {pi}}2 = (0.65 ± 0.29) GeV2. These parameters are useful input to non-perturbative QCD corrections to the semileptonic B decay rate and the determination of the CKM parameter.

Download or read book Study of B S Gamma at BaBar Using the Sum of Exclusive Modes written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The electromagnetic penguin process b [yields] s[gamma] is very interesting to theorists because it can be used to constrain contributions from new physics that could enter at the one loop level. The high statistics of B[bar B] events collected at the BABAR experiment make a measurement of this rare decay possible. The branching fraction of a sum of exclusive b [yields] s[gamma] decay modes is measured as a function of the strange hadronic mass. This is a large step toward the measurement of the b [yields] s[gamma] rate.

Download or read book Analysis of Br anti B X s Gamma at NNLO with a Cut on Photon Energy written by and published by . This book was released on 2006 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: By combining a recent estimate of the total {bar B} → X{sub s}[gamma] branching fraction at O([alpha]{sub s}2) with a detailed analysis of the effects of a cut E{sub [gamma]} ≥ 1.6 GeV on photon energy, a prediction for the partial {bar B} → X{sub s}[gamma] branching fraction at next-to-next-to-leading order in renormalization-group improved perturbation theory is obtained, in which contributions from all relevant scales are properly factorized. The result Br({bar B} → X{sub s}{gamma}) = (2.98 ± 0.26) · 10−4 is about 1.4[sigma] lower than the experimental world average. This opens a window for significant New Physics contributions in rare radiative B decays.

Download or read book Measurement of B Decays to Phi K Gamma written by B. Aubert and published by . This book was released on 2006 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: We measure the branching fraction of the radiative B{sup -} decay {Beta}(B{sup -} {yields} {phi}K{sup -}{gamma}) = (3.46 {+-} 0.57{sub -0.37}{sup +0.39}) x 10{sup -6}, and set an upper limit on the radiative {bar B}{sup 0} decay {Beta}({bar B}{sup 0} {yields} {phi}{bar K}{sup 0}{gamma})

Download or read book Measurement of the Branching Fraction of the Exclusive Decay B0 K 0gamma written by and published by . This book was released on 2000 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The b → s[gamma] transition proceeds by a loop penguin diagram. It may be used to measure precisely the couplings of the top quark and to search for the effects of any new particles appearing in the loop. We present a preliminary measurement of the branching fraction of the exclusive decay, B° → K*°[gamma]. They use 8.6 x 106 B{bar B} decays to measure B(B° → K*°[gamma]) = (5.4 ± 0.8 ± 0.5) x 10−5.

Download or read book Measurement of the B to Xs GammaBranching Fraction and Photon Energy Spectrum Usingthe Recoil Method written by and published by . This book was released on 2007 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the branching fraction and photon energy spectrum for the decay B → X{sub s}[gamma] using data from the BABAR experiment. The data sample corresponds to an integrated luminosity of 210 fb−1, from which approximately 680,000 B{bar B} events are tagged by a fully reconstructed hadronic decay of one of the B mesons. In the decay of the second B meson, an isolated high-energy photon is identified. We measure [Beta](B → X{sub s}[gamma]) = (3.66 ± 0.85{sub stat} ± 0.60{sub syst}) x 10−4 for photon energies E{sub {gamma}} above 1.9 GeV in the B rest frame. From the measured spectrum we calculate the first and second moments for different minimum photon energies, which are used to extract the heavy-quark parameters m{sub b} and [mu]{sub {pi}}2. In addition, measurements of the direct CP asymmetry and isospin asymmetry are presented.

Download or read book Search for the Decay B 2 gamma gamma written by and published by . This book was released on 2001 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a limit on the branching fraction for the decay B° 2![gamma][gamma] using data collected at the [Upsilon](4S) resonance with the BABAR detector at the PEP-II asymmetric--energy ee− collider. Based on the observation of one event in the signal region, out of a sample of 21.3 x 106 ee− 2 2!B{bar B} decays, we establish an upper limit on the branching fraction of [Beta] (B° 2![gamma][gamma])

Download or read book Study of B S Gamma at BaBar Using the Sum of Exclusive Modes written by Teela Maria Pulliam and published by . This book was released on 2002 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Study of Inclusive And Exclusive B X U L Nu Decays And the Measurement of written by and published by . This book was released on 2005 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report studies of B → X{sub u}l[nu] decays, based on a sample of 88 million B{bar B} events recorded with the BABAR detector. From both tagged and untagged B{bar B} events we have isolated inclusive charmless decays in kinematic regions for which the dominant background from B → X{sub c}l[nu] is reduced by making requirements on different variables: the electron energy E{sub l}, the momentum transfer q2, and the hadronic mass m{sub X}. Using theoretical calculations we extrapolate to the total decay rate to determine the CKM matrix element.

Download or read book Measurements of B V Gamma Decays written by Aaron Kevin Yarritu and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Observational evidence and theoretical motivation have led us to the conclusion that our current understanding of the universe is incomplete. While new physics is expected to exist above the electroweak scale, its influence can be detected by experiments that operate below this scale. The Babar experiment has recorded approximately 432 fb-1 of data at the center of mass energy of 10.58 GeV, which corresponds to the Y(4S) mass. One of the physics programs is studying radiative decays of the B meson. These decays primarily proceed through loop diagrams, and thus influences of new particles may be detectable. In this thesis, I present results of the measurements of the branching fractions, CP asymmetry, and isospin asymmetry of B -> K* gamma. Results are also presented for the measurements of the branching fractions of B -> rho(omega) gamma. Finally, a search for the decay of B -> phi gamma is given.

Download or read book Study of the B Xs gamma Decay with a Fully Inclusive Technique at the BABAR Detector written by Francesca Bucci and published by . This book was released on 2005 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: