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Bbar {right arrow} {pi}l {nu bar}}at three lattice spacings

Description: The increasing accuracy of experimental results for the exclusive, semileptonic decay {anti B}{yields}{pi}l{anti {nu}} requires a similarly acucrate calculation of the hadronic matrix elements, to determine {vert_bar}V{sub ub}{vert_bar}. We present preliminary results for the form factors of the B to light meson decay mode. Using results from three lattices in the range 5.7{<=}{beta}{<=}6.1 we study the dependence on the lattice spacing.
Date: November 1, 1998
Creator: S. Ryan, A. El-Khadra, S. Hashimoto, A. Kronfeld, P. Mackenzie, and J. Simone
Partner: UNT Libraries Government Documents Department

B physics at the tevatron

Description: Precision B-physics results from the CDF and D0 Collaborations based on data collected during the Tevatron 1992-96 run are presented. In particular we discuss the measurement of the B{sub s} meson lifetime, B{sub c} meson observation, and B{sup 0} - {anti B}{sup 0} mixing results obtained using time-evolution analyses. Prospects for the next Tevatron run, starting in 1999, are also reported.
Date: July 1, 1998
Partner: UNT Libraries Government Documents Department

Measurement of B{sup 0}/Bbar{sup 0} {right arrow}J/{psi} K(0 over s) decay asymmetry using same-side b-flavor tagging

Description: We present a measurement of the time-dependent asymmetry in the rate for {anti B}{sup 0} versus B{sup 0} decays to J/{psi}K{sup 0}{sub s}. The data sample consists of 198 {+-} 17 B{sup 0}/{anti B}{sup 0} decays collected by the CDF detector in p{anti p} collisions at the Fermilab Tevatron, where the initial b flavor has been determined by a same-side flavor tagging technique. This asymmetry is interpreted in the Standard Model as a measurement of the CP-violation parameter sin(2{beta}). Our analysis results in sin(2{beta}) = 1:8 {+-} 1:1(stat) {+-} 0:3(syst).
Date: October 1, 1998
Creator: Tseng, J.
Partner: UNT Libraries Government Documents Department

Measurement of time-dependent B{sup 0}-{anti B}{sup 0} flavor oscillation at CDF

Description: The time dependence of B{sup 0}-{anti B}{sup 0} oscillations has been studied using several techniques by the CDF experiment at Fermilab. The data comprise 110 pb{sup {minus}1} of p{anti p} collisions at {radical}s = 1.8 TeV. Preliminary measurements of the B{sup 0}-{anti B}{sup 0} oscillation frequency ({Delta}m{sub d}) will be presented.
Date: April 1, 1998
Creator: Ribon, A.
Partner: UNT Libraries Government Documents Department

Exclusive versus inclusive semileptonic {anti B} decays in the quark model

Description: Some emerging difficulties in the theoretical description of exclusive semileptonic {anti B} decays are discussed in the context of the quark model. While there are no unambiguous problems at this time, the author discusses physics beyond the valence quark model which should eventually be probed by precision measurements of B semileptonic decays.
Date: October 1, 1996
Creator: Isgur, Nathan
Partner: UNT Libraries Government Documents Department

Two recent results on B physics from CDF

Description: Preliminary results from two recent CDF b physics analyses are presented. The first obtains sin(2{beta})=0.79<sup>+0.41</sup><sub>-0.44</sub> from a measurement of the asymmetry in B<sup>0</sup>, {anti B<sup>0</sup>} {yields} J/{psi}K<sup>0</sup><sub>s</sub> decays, providing the best direct indication so far that CP invariance is violated in the b sector. The second obtains new results on the parity even (A<sub>0</sub> and A<sub>{parallel}</sub>) and odd (A<sub>{perpendicular}</sub>) polarization amplitudes from full angular analyses of B<sup>0</sup> {yields} J/{psi}K*<sup>0</sup> and B<sup>0</sup><sub>s</sub> {yields} J/{psi}{phi} decays: B<sup>0</sup>: {A<sub>0</sub> = 0.770 &plusmn; 0.039 &plusmn; 0.012; A<sub>{parallel}</sub> = (0.530 &plusmn; 0.106 &plusmn; 0.034)e<sup>(2.16 &plusmn; 0.46 &plusmn; 0.10)i</sup>; A<sub>{perpendicular}</sub> = (0.355 &plusmn; 0.156 &plusmn; 0.039)e<sup>(-0.56 &plusmn; 0.53 &plusmn; 0.12)i</sup>}, B<sup>0</sup><sub>s</sub>: {A<sub>0</sub> = 0.778 &plusmn; 0.090 &plusmn; 0.012; A<sub>{parallel}</sub> = (0.407 &plusmn; 0.232 &plusmn; 0.034)e<sup>(1.12 &plusmn; 1.29 &plusmn; 0.11)</sup>i; {vert_bar}A<sub>{perpendicular}</sub> = 0.478 &plusmn; 0.202 &plusmn; 0.040.
Date: June 29, 1999
Creator: Schmidt, M. P.
Partner: UNT Libraries Government Documents Department

Recent theoretical developments in B --&gt;Xs l+ l- decays

Description: We present a concise review of the theoretical status of the rare semileptonic {bar B} {yields} X{sub s}{ell}{sup +}{ell}{sup -} decays in the standard model. Particular attention is thereby devoted to the recent theoretical progress concerning, on the one hand the next-to-next-to-leading order QCD calculation and, on the other hand the analysis of phenomenological important subleading electroweak effects.
Date: May 18, 2004
Creator: Haisch, Ulrich
Partner: UNT Libraries Government Documents Department

Measurement of the CP violation parameter sin(2{beta}) in B{sup 0} {r_arrow}J/{psi} K{sub s}{sup 0} Decays

Description: A sample of {approximately} 400 B{sub d}{sup 0}/{bar B}{sub d}{sup 0} {r_arrow} J/{psi}K{sub s}{sup 0} decays collected in {bar p}p collisions by the CDF detector is used to directly measure the CP-violation parameter sin (2{beta}). They find sin(2{beta}) = 0.79{sub {minus}0.44}{sup + 0.41}, favoring the standard model expectation of a large CP violation in this B{sup 0} decay mode.
Date: September 2, 1999
Creator: Bauer, G.
Partner: UNT Libraries Government Documents Department

B physics at CDF

Description: B physics results from the CDF Collaboration based on data collected during the 1992-1996 Tevatron run are presented. In particular, we report the discovery of the B{sub c} meson in the semileptonic decay B{sub c} {yields} J/{psi}l{nu}X, updates of b hadrons lifetime measurements, with a description of the B{sub s} lifetime measurement, the B{sup 0}{sub d} - {anti B}{sup 0}{sub d} mixing results and the limits set on rare B decay branching ratios. Current results are used to extrapolate B physics prospects for the future high luminosity run II.
Date: September 1, 1998
Creator: Donati, S.
Partner: UNT Libraries Government Documents Department

Recent results from CDF

Description: We first present recent CDF results on the top quark, covering the measurement of the t{anti t} production cross section and the top quark mass, the observation of hadronic W decays in top events, the measurement of V{sub tb}, the search for flavor changing neutral current decays, and kinematical properties of t{anti t} production. Then we present one topic from CDF exotic physics results, i.e., the search for first-generation leptoquarks, and one topic from CDF B physics results, i.e., the measurement of time-dependent B{sup 0}-{anti B}{sup 0} mixing. Finally we conclude by briefly mentioning the prospects for Run II.
Date: February 15, 1998
Creator: Takikawa, K. & CDF
Partner: UNT Libraries Government Documents Department

The Bbar ---&gt; D* l nu bar form factor at zero recoil and the determination of |V{sub cb}|

Description: We summarize our lattice QCD study of the form factor at zero recoil in the decay {bar B} {yields} D*{ell}{bar {nu}}. After careful consideration of all sources of systematic uncertainty, we find, h{sub A{sub 1}}(1) = 0.913{sub -17-30}{sup +24+17}, where the first uncertainty is from statistics and fitting while the second combined uncertainty is from all other systematic effects.
Date: November 26, 2001
Creator: al., J.N. Simone et
Partner: UNT Libraries Government Documents Department

Mixing-induced CP asymmetries in radiative B decays in and beyond the Standard Model

Description: In the Standard Model (SM) the photon in radiative {anti B}{sup 0} and {anti B}{sub s} decays is predominantly left-handed. Thus, mixing induced CP asymmetries in b {r_arrow} s{gamma} and b {r_arrow} d{gamma} are suppressed by m{sub s}/m{sub b} and m{sub d}/m{sub b}, respectively, and are very small. In many extensions of the SM, such as the left-right symmetric model (LRSM), SU(2)xU(1) models with exotic fermions and SUSY, the amplitude of right-handed photons grows proportional to the virtual heavy fermion mass, which can lead to large asymmetries. As an example, in the LRSM, asymmetries larger than 50% are possible even when radiative decay rate measurements agree with SM predictions.
Date: April 1, 1997
Creator: Gronau, M.; Atwood, D. & Soni, A.
Partner: UNT Libraries Government Documents Department

Measurement of the CP asymmetry parameter sin(2{beta}) at CDF.

Description: We present a measurement of the time-dependent asymmetry in the rate for {bar B}{sub d}{sup 0} versus B{sub d}{sup 0} decays to J/{psi}K{sub S}{sup 0}. In the context of the Standard Model this is interpreted as a measurement of the CP-violation parameter sin(2{beta}). A total of 198 {+-} 17 B{sub d}{sup 0}/{bar B}{sub d}{sup 0} decays were observed in p{bar p} collisions at {radical}s = 1.8 TeV by the CDF detector at the Fermilab Tevatron. The initial b-flavor is determined by a same side flavor tagging technique. Our analysis results in sin(2{beta}) = 1.8 {+-} 1.1(stat) {+-} 0.3(syst).
Date: October 14, 1998
Creator: LeCompte, T. J.
Partner: UNT Libraries Government Documents Department

Observation of the decay B0bar -> LambdaC antiproton pi0

Description: In a sample of 467 million B{bar B} pairs collected with the BABAR detector at the PEP-II collider at SLAC we have observed the decay {bar B}{sup 0} {yields} {Lambda}{sub c}{sup +}{bar p}{pi}{sup 0} and measured the branching fraction to be (1.94 {+-} 0.17 {+-} 0.14 {+-} 0.50) x 10{sup -4}, where the uncertainties are statistical, systematic, and the uncertainty on the {Lambda}{sub c}{sup +} {yields} pK{sup -}{pi}{sup +} branching fraction, respectively. We determine an upper limit of 1.5 x 10{sup -6} at 90% C.L. for the product branching fraction {Beta}({bar B}{sup 0} {yields} {Sigma}{sub c}{sup +}(2455){bar p}) x {Beta}({Lambda}{sub c}{sup +} {yields} pK{sup -}{pi}{sup +}). Furthermore, we observe an enhancement at the threshold of the invariant mass of the baryon-antibaryon pair.
Date: August 26, 2010
Creator: Aubert, B.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X. et al.
Partner: UNT Libraries Government Documents Department

Search for T, CP and CPT Violation in B0-B0bar Mixingwith Inclusive Dilepton Events

Description: The authors report the results of a search for T, CP and CPT violation in B{sup 0}-{bar B}{sup 0} mixing using an inclusive dilepton sample collected by the BABAR experiment at the PEP-II B Factory. Using a sample of 232 million B{bar B} pairs, with a simultaneous likelihood fit of the same-sign and opposite-sign dileptons, they measure the T and Cp violation parameter |q/p|-1 = (-0.8 {+-} 2.7(stat.) {+-} 1.9(syst.)) x 10{sup -3}, and the CPT and CP parameters Im z = (-13.9 {+-} 7.3(stat.) {+-} 3.2(syst.)) x 10{sup -3} and {Delta}{Lambda} x Re z = (-7.1 {+-} 3.9(stat.) {+-} 2.0(syst.)) x 10{sup -3} ps{sup -1}. The statistical correlation between the measurements of Im z and {Delta}{Lambda} x Re z is 76%.
Date: March 31, 2006
Creator: Aubert, B.
Partner: UNT Libraries Government Documents Department

CP violation in the K and B systems

Description: Although CP violation was discovered more than thirty years ago, its origin is still unknown. In these lectures, we describe the CP- violating effects which have been seen in K decays, and explain how CP violation can be caused by the Standard Model weak interaction. The hypothesis that this interaction is indeed the origin of CP violation will be incisively tested by future experiments on B and K decays. We explain what quantities these experiments will try to determine, and how they will be able to determine them in a theoretically clean way. To clarify the physics of the K system, we give a phase-convention-free description of CP violation in this system. We conclude by briefly exploring whether electric dipole moments actually violate CP even if CPT invariance is not assumed.
Date: November 1, 1996
Creator: Kayser, B.
Partner: UNT Libraries Government Documents Department

B mixing and CP violation at CDF

Description: The mixing of the neutral {bold B} mesons and the violation of CP symmetry in the {bold B} sector can be investigated at the Tevatron proton-antiproton collider. The most severe challenge that these measurements pose is tagging the flavor of a B meson at production. Here we present in detail the method of same side tagging (SST), which is used to obtain new measurement of the {ital B}{sup 0} mass difference {Delta}{ital m{sub d}} = 0.446 {+-} 0.057({ital stat}) + 0. 034 - 0.031({ital syst}) ps{sup -1}. The significance of SST and other tagging methods for physics during Run II of the Tevatron is discussed.
Date: November 1, 1996
Creator: Boudreau, J.
Partner: UNT Libraries Government Documents Department

Lattice QCD and the unitarity triangle

Description: Theoretical and computational advances in lattice calculations are reviewed, with focus on examples relevant to the unitarity triangle of the CKM matrix. Recent progress in semi-leptonic form factors for B {yields} {pi}/v and B {yields} D*lv, as well as the parameter {zeta} in B{sup 0}-{bar B}{sup 0} mixing, are highlighted.
Date: December 3, 2001
Creator: Kronfeld, Andreas S
Partner: UNT Libraries Government Documents Department

b{bar b} production correlations, b{bar b} mixing and {epsilon}{sub B} at CDF

Description: We present preliminary measurements of b{bar b} production correlations, the average B{bar B} mixing, and a limit on the CP violating parameter {epsilon}{sub b} using dimuon events from the dual semileptonic decay of b{bar b}. Data used in this analysis was taken during the 1992--1993 CDF run of the Fermilab Tevatron collider with an integrated luminosity of 17.4 {plus_minus} 0.6 pb{sup {minus}1}. The results on b{bar b} production correlations are compared to predictions of next-to-leading order QCD.
Date: July 1, 1995
Creator: Abe, F.
Partner: UNT Libraries Government Documents Department

Masses and lifetimes of B hadrons

Description: The latest measurements of the masses and lifetimes of weakly decaying B hadrons from experiments at e{sup +}e{sup {minus}} and p{bar p} colliders are presented. These measurements include the lifetimes of the {bar B} {sup o}, {bar B}{sup o} {sub s}, B{sup {minus}} and b baryons, as well as searches for the B{sub c} meson. The observation of B*, p-wave B mesons (B**), and excited b baryons using inclusive and exclusive B hadron reconstruction are discussed. Results on b quark flavour tagging are given.
Date: February 1, 1996
Creator: Kkkroll, I.J.
Partner: UNT Libraries Government Documents Department

CP Violation in B Decays at the Tevatron

Description: Between 1992 to 1996, the CDF and D0 detectors each collected data samples exceeding 100 pb{sup {minus}1} of p{bar p} collisions at {radical}s = 1.8 TeV at the Fermilab Tevatron. These data sets led to a large number of precision measurements of the properties of B hadrons including lifetimes, masses, neutral B meson flavor oscillations, and relative branching fractions, and to the discovery of the B{sub 0} meson. Perhaps the most exciting result was the first look at the CP violation parameter sin ({vert_bar}2{beta}){vert_bar} using the world's largest sample of fully reconstructed B{sup 0}/{bar B}{sup 0} {r_arrow} J/{psi}K{sub s}{sup 0} decays. A summary of this result is presented here. In the year 2000, the Tevatron will recommence p{bar p} collisions with an over order of magnitude expected increased in integrated luminosity (1 fb{sup {minus}1} per year). The CDF and D0 detectors will have undergone substantial upgrades, particularly in the tracking detectors and the triggers. With these enhancements, the Tevatron B physics program includes precision measurements of sin(2{beta}) and B{sub s}{sup 0} flavor oscillations, as well as studies of rare B decays that are sensitive to new physics. The studies of B{sub s}{sup 0} mesons will be particularly interesting as this physics will be unique to the Tevatron during the first half of the next decade.
Date: September 17, 1999
Creator: Kroll, I. Joseph
Partner: UNT Libraries Government Documents Department