549 Matching Results

Search Results

Advanced search parameters have been applied.

Weak matrix elements on the lattice - Circa 1995

Description: Status of weak matrix elements is reviewed. In particular, e{prime}/e, B {yields} K*{gamma}, B{sub B} and B{sub B}, are discussed and the overall situation with respect to the lattice effort and some of its phenomenological implications are summarised. For e{prime}/e the need for the relevant matrix elements is stressed in view of the forthcoming improved experiments. For some of the operators, (e.g. O{sub 6}), even bound on their matrix elements would be very helpful. On B {yields} K{degrees}{gamma}, a constant behavior of T{sub 2} appears disfavored although dependence of T{sub 2} could, of course, be milder than a simple pole. Improved data is badly needed to settle this important issue firmly, especially in view of its ramification for extractions of V{sub td} from B {yields} {rho}{gamma}. On B{sub {kappa}}, the preliminary result from JLQCD appears to contradict Sharpe et al. JLQCD data seems to fit very well to linear {alpha} dependence and leads to an appreciably lower value of B{sub {kappa}}. Four studies of B{sub {kappa}} in the {open_quotes}full{close_quotes} (n{sub f} = 2) theory indicate very little quenching effects on B{sub {kappa}}; the full theory value seems to be just a little less than the quenched result. Based on expectations from HQET, analysis of B-parameter (B{sub h}{ell}) for the heavy-light mesons via B{sub h}{ell}) = constant + constants{prime}/m{sub h}{ell} is suggested. A summary of an illustrative sample of hadron matrix elements is given and constraints on CKM parameters (e.g. V{sub td}/V{sub ts}, on the unitarity triangle and on x{sub s}/x{sub d}, emerging from the lattice calculations along with experimental results are briefly discussed. In quite a few cases, for the first time, some indication of quenching errors on weak matrix elements are now becoming available.
Date: October 3, 1995
Creator: Soni, A.
Partner: UNT Libraries Government Documents Department

Rare b decays from the CDF experiment

Description: The high cross-section for the production of b quarks at the Tevatron hadron collider make it an ideal place to search for rare B meson species and very low branching fraction decay modes of the more common B mesons. This paper reports the recent discovery of the Bc meson by the CDF collaboration. It also discusses the observation of rare B meson final states involving {psi}(2S) mesons and searches for ultra-rare decays such as B {yields} {mu}{sup +}{mu}{sup -}
Date: October 1, 1998
Creator: Trischuk, W.
Partner: UNT Libraries Government Documents Department

B {right arrow}Dl{nu}form factors and the Determination of |V{sub cb}|

Description: The zero recoil limit of the B{yields}Dl{nu} form factors is calculated on the lattice, which provides a model-independent determination of {vert_bar}V{sub cb}{vert_bar}. Considering a ratio of form factors, in which the bulk of statistical and systematic errors cancel, we obtain a precise result both for h{sub +}(1) and for h{sub -}(1).
Date: November 1, 1998
Creator: al., S.Hashimoto et
Partner: UNT Libraries Government Documents Department

Prospects for mixing and CP violation at the Tevatron

Description: The Fermilab p{bar p} Tevatron collider, operating at {radical}s = 1. 8 TeV, is a proficient source of B hadrons. The first collider run, Run I, has clearly proven that B states can be observed cleanly and can be studied in great detail in a hadron collider environment. In this presentation the future of the study of B{bar B} mixing and of CP violation at the Tevatron, with an upgraded machine and detectors, is discussed.
Date: December 1, 1996
Creator: Rijssenbeek, M. & collaborations, The CDF and DO
Partner: UNT Libraries Government Documents Department

CP violation, mixing and rare decays at the Tevatron now and in Run II

Description: We review the status of current B mixing and CP violation measurements from the Fermilab Tevatron. With the existing data sample, the CDF collaboration has made competitive measurements of B{sub d}{sup 0} mixing; set limits on B{sub s}{sup 0} mixing and has begun a direct search of CP violation in the B system through the decay B{sup 0}/{anti B}{sup 0}{yields}J/{psi}K{sub S}{sup 0}. The prospects for future b measurements at the Tevatron, including CP violation, B{sub s}{sup 0} mixing and rare decay searches are discussed.
Date: December 1, 1998
Creator: Pitts, Kevin T.
Partner: UNT Libraries Government Documents Department

Theoretical developments in inclusive B decays

Description: Some recent theoretical work on inclusive B decays relevant for the model independent determination of {vert_bar}V{sub ub}{vert_bar} and {vert_bar}V{sub cb}{vert_bar} is summarized. The theoretical predictions and their reliability for several differential decay distributions in {anti B}{yields}X{sub c,u}e{anti {nu}} and {anti B}{yields}X{sub s}{gamma} are reviewed. These can be used to determine certain important HQET matrix elements. The upsilon expansion and ways of testing it are discussed.
Date: May 17, 1999
Creator: Ligeti, Zoltan
Partner: UNT Libraries Government Documents Department

B Decays as a probe of spontaneous cp-violation in SUSY models

Description: We consider phenomenological implications of susy models with spontaneously broken CP-symmetry. In particular, we analyze CP-asymmetries in B decays and find that the predictions of these models are vastly different from those of the SM. These features are common to NMSSM-like models with an arbitrary number of sterile superfields and the MSSM with broken R-parity.
Date: July 8, 1999
Creator: Lebedev, Oleg
Partner: UNT Libraries Government Documents Department

Low Emittance Tuning Studies for SuperB

Description: SuperB[1] is an international project for an asymmetric 2 rings collider at the B mesons cm energy to be built in the Rome area in Italy. The two rings will have very small beam sizes at the Interaction Point and very small emittances, similar to the Linear Collider Damping Rings ones. In particular, the ultra low vertical emittances, 7 pm in the LER and 4 pm in the HER, need a careful study of the misalignment errors effects on the machine performances. Studies on the closed orbit, vertical dispersion and coupling corrections have been carried out in order to specify the maximum allowed errors and to provide a procedure for emittance tuning. A new tool which combines MADX and Matlab routines has been developed, allowing for both corrections and tuning. Results of these studies are presented.
Date: July 6, 2012
Creator: Liuzzo, Simone; /INFN, Pisa; Biagini, Maria; /INFN, Rome; Raimondi, Pantaleo; /INFN, Rome et al.
Partner: UNT Libraries Government Documents Department

A Search for the Decay Modes B +/- to h +/- tau l

Description: We present a search for the lepton flavor violating decay modes B{sup {+-}} {yields} h{sup {+-}} {tau}{ell} (h = K, {pi}; {ell} = e, {mu}) using the BABAR data sample, which corresponds to 472 million B{bar B} pairs. The search uses events where one B meson is fully reconstructed in one of several hadronic final states. Using the momenta of the reconstructed B, h, and {ell} candidates, we are able to fully determine the {tau} four-momentum. The resulting {tau} candidate mass is our main discriminant against combinatorial background. We see no evidence for B{sup {+-}} {yields} h{sup {+-}} {tau}{ell} decays and set a 90% confidence level upper limit on each branching fraction at the level of a few times 10{sup -5}.
Date: July 20, 2012
Creator: Lees, J.P.
Partner: UNT Libraries Government Documents Department

Observation of the Rare Decay B+ \to K+pi0pi0 and Measurement of the Quasi-two Body Contributions B+ \to K*(892)+pi0, B+ \to f0(980)K+ and B+ \to chic0K+

Description: We report an analysis of charmless hadronic decays of charged B mesons to the final state K{sup +}{pi}{sup 0}{pi}{sup 0}, using a data sample of (470.9 {+-} 2.8) x 10{sup 6} B{bar B} events collected with the BABAR detector at the {Gamma}(4S) resonance. We observe an excess of signal events, with a significance above 10 standard deviations including systematic uncertainties, and measure the branching fraction and CP asymmetry to be {Beta}(B{sup +} {yields} K{sup +}{pi}{sup 0}{pi}{sup 0}) = (16.2 {+-} 1.2 {+-} 1.5) x 10{sup -6} and A{sub CP}(B{sup +} {yields} K{sup +}{pi}{sup 0}{pi}{sup 0}) = -0.06 {+-} 0.06 {+-} 0.04, where the uncertainties are statistical and systematic, respectively. Additionally, we study the contributions of the B{sup +} {yields} K{sup +}(892){sup +}{pi}{sup 0}, B{sup +} {yields} f{sub 0}(980)K{sup +}, and B{sup +} {yields} {chi}{sub c0}K{sup +} quasi-two-body decays. We report the world's best measurements of the branching fraction and CP asymmetry of the B{sup +} {yields} K{sup +}{pi}{sup 0}{pi}{sup 0} and B{sup +} {yields} K{sup +}(892){sup +}{pi}{sup 0} channels.
Date: December 13, 2011
Creator: Lees, J.P.; Poireau, V.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E. et al.
Partner: UNT Libraries Government Documents Department

Electromagnetic Mass Splittings in Heavy Mesons

Description: The electromagnetic contribution to the isomultiplet mass splittings of heavy mesons is reanalyzed within the framework of the heavy mass expansion. It is shown that the leading term in the expansion is given to a good approximation by the elastic term. 1/mQ-corrections can only be estimated, the main source of uncertainty now being inelastic contributions. The 1/mQ-corrections to the elastic term turn out to be relatively small in both D and B mesons.
Date: November 1, 1992
Creator: Goity, Jose
Partner: UNT Libraries Government Documents Department

Measurement of the Branching Fraction for the DecayB^{\pm} to K^{*\pm} gamma, K^{*\pm} toK^{\pm} \pi^{0} with the BaBar Detector

Description: The branching fraction of the radiative penguin B meson decay B{sup {+-}} {yields} K*{sup {+-}}{gamma} is measured at the PEP-II asymmetric energy e{sup +}e{sup -} collider, operating at a center of momentum energy of 10.58 GeV, the {Upsilon}(4S) resonance. This document concentrates on the case K*{sup {+-}} {yields} K{sup {+-}}{pi}{sup 0}; {pi}{sup 0} {yields} {gamma}{gamma}. This analysis is based on a dataset of 88.2-million {Upsilon}(4S) {yields} B{bar B} events corresponding to 81.3 fb{sup -1} collected with the BABAR detector.
Date: September 8, 2006
Creator: koeneke, K.
Partner: UNT Libraries Government Documents Department

A Measurement of the Branching Fractions ofexclusive Bbar to D(*)(pi)lnu Decays in Events with a Fully Reconstructed BMeson

Description: The authors report a measurement of the branching fractions for {bar B} {yields} D{sup (*)}{pi}{ell}{sup -}{bar {nu}}{sub {ell}} decays based on 341.1 fb{sup -1} of data collected at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II e{sup +}e{sup -} storage rings. Events are tagged by fully reconstructing one of the B mesons in a hadronic decay mode. The obtain {Beta}(B{sup -} {yields} D{sup 0}{ell}{sup -}{bar {nu}}{sub {ell}}) = (2.33 {+-} 0.09{sub stat.} {+-} 0.09{sub syst.})%, {Beta}(B{sup -} {yields} D*{sup 0}{ell}{sup -}{bar {nu}}{sub {ell}}) = 5.83 {+-} 0.15{sub stat.} {+-} 0.30{sub syst.}%, {Beta}({bar B}{sup 0} {yields} D{sup +}{ell}{sup -}{bar {nu}}{sub {ell}}) = (2.21 {+-} 0.11{sub stat.} {+-} 0.12{sub syst.})% {Beta}({bar B}{sup 0} {yields} D*{sup +}{ell}{sup -}{bar {nu}}{sub {ell}}) = 5.49 {+-} 0.16{sub stat.} {+-} 0.25{sub syst.}%, {Beta}(B{sup -} {yields} D{sup +}{pi}{sup -}{ell}{sup -}{bar {nu}}{sub {ell}}) = (0.42 {+-} 0.06{sub stat.} {+-} 0.03{sub syst.})%, {Beta}(B{sup -} {yields} D*{sup +} {pi}{sup -}{ell}{sup -}{bar {nu}}{sub {ell}}) = (0.59 {+-} 0.05{sub stat.} {+-} 0.04{sub syst.})%, {Beta}({bar B}{sup 0} {yields} D{sup 0}{pi}{sup +}{ell}{sup -}{bar {nu}}{sub {ell}}) = (0.43 {+-} 0.08{sub stat.} {+-} 0.03{sub syst.})% and {Beta}({bar B}{sup 0} {yields} D*{sup 0} {pi}{sup +}{ell}{sup -}{bar {nu}}{sub {ell}}) = (0.48 {+-} 0.08{sub stat.} {+-} 0.04{sub syst.})%.
Date: January 8, 2008
Creator: Aubert, B.
Partner: UNT Libraries Government Documents Department

Measurements of sin2beta at BaBar with Charmonium and Penguin Decays

Description: This article summarizes measurements of time-dependent CP asymmetries in decays of neutral B mesons to charmonium, open-charm and gluonic penguin-dominated charmless final states. Unless otherwise stated, these measurements are based on a sample of approximately 230 million {Upsilon}(4S) {yields} B{bar B} decays collected by the BABAR detector at the PEP-II asymmetric-energy B-factory.
Date: December 14, 2005
Creator: George, Katherine A. & U., /Liverpool
Partner: UNT Libraries Government Documents Department

Measurements of the CKM Angle Beta/Phi(1) at the B Factories

Description: We report measurements of time-dependent CP asymmetries related to the CKM angle {beta}/{phi}{sub 1}, using decays of neutral B mesons to charmonium, open charm and in b {yields} s loop-dominated processes. A preliminary measurement of time-dependent CP asymmetries in B{sup 0} {yields} {rho}{sup 0}(770)K{sub S}{sup 0} decays from the BABAR experiment is given here.
Date: August 23, 2006
Creator: Ocariz, J. & /Paris U., VI-VII
Partner: UNT Libraries Government Documents Department

B^0 to \pi^+ \pi^- \pi^0Time Dependent Dalitz Analysis at BaBar

Description: The author presents here results of a time-dependent analysis of the Dalitz structure of neutral B meson decays to {pi}{sup +}{pi}{sup -}{pi}{sup 0} from a dataset of 346 million B{bar B} pairs collected at the {Upsilon}(4S) center of mass energy by the BaBar detector at the SLAC PEP-II e{sup +}e{sup -} accelerator. No significant CP violation effects are observed and 68% confidence interval is derived on the weak angle {alpha} to be [75,152].
Date: April 6, 2007
Creator: Cavoto, Gianluca
Partner: UNT Libraries Government Documents Department

Search for B Meson Decays to eta' eta' K

Description: The authors describe searches for decays of B mesons to the charmless final states {eta}'{eta}'K. The data consist of 228 million B{bar B} pairs produced in e{sup +}e{sup -} annihilation, collected with the BABAR detector at the Stanford Linear Accelerator Center. The 90% confidence level upper limits for the branching fractions are {Beta}(B{sup 0} {yields} {eta}'{eta}'K{sup 0}) < 31 x 10{sup -6} and {Beta}(B{sup +} {yields} {eta}'{eta}'K{sup +}) < 25 x 10{sup -6}.
Date: May 5, 2006
Creator: Aubert, B.
Partner: UNT Libraries Government Documents Department

Recent Results in Electroweak B Decays from the BaBar Experiment

Description: A review of the most recent BABAR results on electroweak penguin B decays is presented. The focus of this paper is on the measurement of observables in the decays B {yields} X{sub s}{gamma}, B {yields} K{sup (*)}l{sup +}l{sup -} B {yields} K{sub s}{sup 0}{pi}{sup 0}{gamma} (time-dependent analysis) and B {yields} ({rho}/{omega}){gamma}.
Date: September 1, 2006
Creator: Koeneke, Karsten & /MIT, LNS /SLAC
Partner: UNT Libraries Government Documents Department

sin 2 beta + gamma Measurements

Description: I report on the most recent measurements done to constrain sin(2{beta}+{gamma}) with neutral B mesons. Direct measurements of 2{beta} + {gamma} will provide a precise test of the standard model predictions with higher statistics. Present constraints come from studies of B {yields} D{sup (*){+-}}{pi}{sup {-+}}/{rho}{sup {-+}} decays done by BABAR and Belle collaborations with full and inclusive techniques to reconstruct B mesons. B {yields} D{sup 0(*)}K{sup 0} decays are also very promising but statistics are too low to give any constraint at the moment.
Date: June 24, 2005
Creator: Therin, G & /Paris U., VI-VII
Partner: UNT Libraries Government Documents Department