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The Heavy Mass Expansion lambda(sub)b -> lambda(sub)c Decays

Description: We point out that in the decays of the lambda(sub)b to lambda(sub)c one can find predictions which - in the framework of the 1/m(sub)c expansion - do not receive corrections in any order of 1/m(sub)c. We discuss QCD corrections to these predictions and examine some of the consequences for nonleptonic decays.
Date: November 1, 1992
Creator: Mannel, Thomas & Roberts, Winston
Partner: UNT Libraries Government Documents Department

Flavor tagging nd CP-violation measurements at the Tevatron

Description: The CDF collaboration has adapted several heavy flavor tagging techniques and employed them in analyses of time-dependent flavor asymmetries using data from the Tevatron Run I. The tagging algorithms were calibrated using low-P{sub t} inclusive lepton and dilepton trigger data samples. The tagging techniques were applied to a sample of {approximately} 400 B{sub d}{sup 0}/{anti B}{sub d}{sup 0} {r_arrow} J/{psi}K{sub s}{sup 0} decays and were used to measure the CP violation parameter, sin(2{beta}). Prospects for future improved measurements of the CP violation parameters at the Tevatron are briefly discussed.
Date: April 28, 1999
Creator: Tkaczyk, S.
Partner: UNT Libraries Government Documents Department

Phenomenological study of strong decays of heavy hadrons in heavy quark effective theory

Description: The application of the tensor formalism of the heavy quark effective theory (HQET) at leading order to strong decays of heavy hadrons is presented. Comparisons between experimental and theoretical predictions of ratios of decay rated for B mesons, D mesons and kaons are given. The application of HQET to strange mesons presents some encouraging results. The spin-flavor symmetry is used to predict some decay rates that have not yet been measured.
Date: December 1999
Creator: Tregoures, N. & Roberts, W.
Partner: UNT Libraries Government Documents Department

EPR in B physics and elsewhere

Description: The application of Einstein-Podolsky-Rosen correlations in {Upsilon}(4s) {yields} B{anti B} decays to research in CP violation is the first and probably only use of EPR as a technique for research in new physics. Elsewhere highly sophisticated EPR projects question EPR and test its predictions to look for violations of quantum mechanics, hidden variables, Bell`s inequalities, etc.
Date: September 1, 1997
Creator: Lipkin, H.J.
Partner: UNT Libraries Government Documents Department

Quark-hadron duality in the 't Hooft model for meson weak decays: Different quark diagram topologies

Description: The authors compare the effects of different quark diagram topologies on the weak hadronic width of heavy-light mesons in the large N{sub c} limit. They enumerate the various topologies and show that the only one dominant (or even comparable) in powers of N{sub c} to the noninteracting spectator ''tree'' diagram is the ''annihilation'' diagram, in which the valence quark-antiquark pair annihilate weakly. They compute the amplitude for this diagram in the 't Hooft model (QCD in 1+1 spacetime dimensions with a large number of colors N{sub c}) at the hadronic level and compare to the Born term partonic level. They find that quark-hadron duality is not well satisfied, even after the application of a smearing procedure to the hadronic result. A number of interesting subtleties absent from the tree diagram case arise in the annihilation diagram case, and are described in detail.
Date: May 1, 1998
Creator: Grinstein, Benjamin & Lebed, Richard F.
Partner: UNT Libraries Government Documents Department

Latest experimental information on {epsilon}{prime}/{epsilon}

Description: The authors review the latest experimental results in search for direct CP-violation by measuring the CP-violating parameters Re({epsilon}{prime}/{epsilon}) in neutral kaon decays. The recent result from Fermilab-KTeV Re({epsilon}{prime}/{epsilon}) = (28.0 {+-} 4.1) x 10{sup {minus}4}, and the new preliminary result from CERN-NA48 Re({epsilon}{prime}/{epsilon}) = (14.0 {+-} 4.3) x 10{sup {minus}4}, are presented. Both experiments, though using very different techniques, have now performed very well by collecting millions of events for all four relevant decay modes of K{sub L,S} to {pi}{sup +}{pi}{sup {minus}} and {pi}{sup 0}{pi}{sup 0} simultaneously. The current world average on this important measurement is Re({epsilon}{prime}/{epsilon}) = 19.3 {+-} 10{sup {minus}4} with a {chi}{sup 2}/ndf = 11.1/5, establishing the existence of direct CP-violation. The experimental status of such crucial measurements and the future prospects are also discussed here.
Date: August 17, 2000
Creator: Hsiung, Yee B.
Partner: UNT Libraries Government Documents Department

The CKM matrix and CP violation

Description: The status of CP violation and the CKM matrix is reviewed. Direct CP violation in B decay has been established and the measurement of sin 2{beta} in {psi}K modes reached 5% accuracy. I discuss the implications of these, and of the possible deviations of the CP asymmetries in b {yields} s modes from that in {psi}K. The first meaningful measurements of {alpha} and {gamma} are explained, together with their significance for constraining both the SM and new physics in B-{bar B} mixing. I also discuss implications of recent developments in the theory of nonleptonic decays for B {yields} {pi}K rates and CP asymmetries, and for the polarization in charmless B decays to two vector mesons.
Date: September 14, 2004
Creator: Ligeti, Zoltan
Partner: UNT Libraries Government Documents Department

Fully reconstructed B-meson decays using J/{psi} and {psi}(2S)

Description: In this paper we present CDF B-meson branching ratio results involving color-suppressed {ital B} {r_arrow} {Psi}{Kappa} decays, where {Psi} = {ital J}/{psi}, {psi}(2{ital S}) and {Kappa} = {Kappa}, {Kappa}{sup *}. Fully reconstructed decays of {ital B} {r_arrow} {ital J}/{psi}{Kappa}, {ital B} {r_arrow} {psi}(2{ital S}){Kappa}, {ital B}{sup +} {r_arrow} {ital J}/{psi}{pi}{sup +} and {ital B}{sub s} {r_arrow} {ital J}/{psi}{phi} are used to extract branching ratios, vector-pseudoscalar ratios and polarization parameters.
Date: September 1, 1996
Creator: Miao, Ting
Partner: UNT Libraries Government Documents Department

Precise measurement of the left-right cross section asymmetry in Z boson production by E{sup +}e{sup {minus}} collisions

Description: The authors present a precise measurement of the left-right cross section asymmetry (A{sub LR}) for Z boson production by e{sup +}e{sup {minus}} collisions. The measurement was performed at a center-of-mass energy of 91.26 GeV with the SLD detector at the SLAC Linear Collider (SLC). The luminosity-weighted average polarization of the SLC electron beam was (63.0 {+-} 1.1)%. Using a sample of 49,392 Z decays, they measure A{sub LR} to be 0.1628 {+-} 0.0071 (stat.) {+-} 0.0028(syst.) which determines the effective weak mixing angle to be sin{sup 2} {theta}{sub W}{sup eff} = 0.2292 {+-} 0.0009(stat.) {+-} 0.0004(syst.). They combine this result with the result obtained in 1992 and obtain sin{sup 2} {theta}{sub W}{sup eff} = 0.2294 {+-} 0.0010, which constitutes the best measurement of sin{sup 2} {theta}{sub W}{sup eff} in a single experiment presently available.
Date: September 1, 1994
Creator: Lath, A. & Collaboration, SLD
Partner: UNT Libraries Government Documents Department

D0 top quark cross section for the 1992--1995 tevatron run

Description: We present a measurement of the t{bar t} cross section in p{bar p} collisions at {radical}s = 1.8 TeV using dilepton and single lepton final states. This analysis uses about 100 pb{sup -1} of data collected with the D0 detector at Fermilab during the 1992-1995 run. Analyses in two other final states are also presented. 13 refs., 3 figs., 2 tabs.
Date: October 1, 1996
Creator: Bantly, J.
Partner: UNT Libraries Government Documents Department

Beautiful CP violation

Description: CP violation is observed to date only in K{sup 0} decays and is parameterizable by a single quantity {epsilon}. Because it is one of the least understood phenomena in the Standard Model and holds a clue to baryogenesis, it must be investigated further. Highly specialized searches in K{sup 0} decays are possible. Effects in B decays are much larger. In addition to the traditional B{sub d} {yields} J/{psi}K{sub S}, {pi}{sup +}{pi}{sup {minus}} asymmetries, CP violation could be searched for in already existing inclusive B data samples. The rapid B{sub s}--{anti B}{sub s} oscillations cancel in untagged B{sub s} data samples, which therefore allow feasibility studies for the observation of CP violation and the extraction of CKM elements with present vertex detectors. The favored method for the extraction of the CKM angle {gamma} is shown to be unfeasible and a solution is presented involving striking direct CP violation in charged B decays. Novel methods for determining the B{sub s} mixing parameter {Delta}m are described without the traditional requirement of flavor-specific final states.
Date: September 24, 1997
Creator: Dunietz, I.
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

Search for the H-dibaryon. A proposal to E871

Description: This report consists of vugraphs for a lecture on the search for the H-dibaryon. The physics importance of this search are: (1) low energy test of QCD; (2) new form of matter; (3) missing link between normal hadronic matter and strange matter; (4) astrophysical explanations; and (5) cosmology and dark matter. The author reviews past experiments searching for H-dibaryon. Finally he discusses search methods at E871.
Date: October 1, 1998
Creator: Fitch, V.; Klein, J. & May, M.
Partner: UNT Libraries Government Documents Department

Review of charm lifetimes

Description: A review of the latest experimental results on charm particle lifetimes is presented. The most significant update is that the D{sub s}{sup +} lifetime is conclusively larger than the D{sup 0} lifetime and signifies that W-exchange/W-annihilation contributions are large. Using new high statistics data on D{sup +} {r{underscore}arrow} K{sup +}{pi}{sup +}{pi}{sup {minus}} together with the D{sub s}{sup +} lifetime and some assumptions, one can phenomenologically extract the strength of the W-exchange contribution in D{sup 0} decays and of W-annihilation in D{sub s}{sup +} decays. These are larger than or at the limit of theoretical expectations using QCD-based operator production expansion techniques.
Date: January 6, 2000
Creator: Cheung, H.W.K.
Partner: UNT Libraries Government Documents Department

A study of the orientation and energy partition of three-jet events in hadronic Z{sup 0} decays

Description: Using hadronic Z{sup 0} decays collected in the SLD experiment at SLAC we have measured the distributions of the jet energies in e{sup +}e{sup -}{yields} Z{sup 0}{yields} three-jet events of the three orientation angles of the event plane. We find that these distributions are well described by perturbative QCD incorporating vector gluons. We have also compared our data with models of scalar and tensor gluon production, and discuss limits on the relative contributions of these particles to three-jet production in e{sup +}e{sup -} annihilation.
Date: July 1, 1995
Creator: The SLD Collaboration
Partner: UNT Libraries Government Documents Department

HQET and Form Factor Effects in B {r_arrow} K{sup (*)} {ell}{sup +}{ell}{sup {minus}}

Description: We examine the rates for the exclusive decays B {r_arrow} K* {ell}{sup +}{ell}{sup {minus}}. We use the scaling predictions of the heavy quark effective theory to extract the necessary form factors from fits to various combinations of data. These data include the D {r_arrow} K*{ell}{nu} semileptonic decays, as well as the nonleptonic decays B{r_arrow}K*{psi}{prime} and the rare decay B {r_arrow} K*{gamma}. We use different parametrizations of form factors, and find that integrated decay rates are not very sensitive to the forms chosen. However, the decay spectra and the forward-backward asymmetry in B {r_arrow} K*{ell}{sup +}{ell}{sup {minus}} are sensitive to the forms chosen for the form factors, while the lepton polarization asymmetry in {bar B}{sup 0} {r_arrow} {bar K}{sup 0} {mu}{sup +} {mu}{sup {minus}} is largely independent of the choice of form factors. Contributions from charmonium resonances dominate the spectra and integrated rates. In our best scenario, we find Br({bar B}{sup 0}) {r_arrow} {bar K}{sup 0} {mu}{sup +}{mu}{sup {minus}} = 2.0 {+-} 0.3 times 10{sup {minus}6} and Br({bar B}{sup 0} {r_arrow} {bar K}*{sup 0} {mu}{sup +} {mu}{sup {minus}}) = 8.1 {+-} 2.0 x 10{sup {minus}6}. We also make predictions for other polarization observables in these decays.
Date: July 1, 1996
Creator: Roberts, W.
Partner: UNT Libraries Government Documents Department

Rare Nonleptonic Decays of the Omega Hyperon: Measurements of the Branching Ratios for Omega-+ --> Xi*0(1530) (anti-Xi*0(1530)) pi-+ and Omega-+ --> Xi-+ pi+- pi-+

Description: A clean signal of 78 (24) events has been observed in the rare nonleptonic particle (antiparticle) decay modes {Omega}{sup {-+}} {yields} {Xi}{sup {-+}}{pi}{sup {+-}}{pi}{sup {-+}} using data collected with the HyperCP spectrometer during Fermilab's 1999 fixed-target run. We obtain B({Omega}{sup -} {yields} {Xi}{sup -}{pi}{sup +}{pi}{sup -}) = [4.32 {+-} 0.56(stat) {+-} 0.28(syst)] x 10{sup -4} and B({Omega}{sup +} {yields} {Xi}{sup +}{pi}{sup -}{pi}{sup +}) = 3.13 {+-} 0.71(stat) {+-} 0.20(syst) x 10{sup -4}. This is the first observation of the antiparticle mode. Our measurement for the particle mode agrees with the previous experimental result and has an order-of-magnitude better precision. We extract the contribution from the resonance decay mode {Omega}{sup {-+}} {yields} {Xi}*{sub 1530}{sup 0} ({ovr {Xi}*{sub 1530}{sup 0}}){pi}{sup {-+}} to the final state {Xi}{sup {-+}}{pi}{sup {+-}}{pi}{sup {-+}}. This the first actual measurement of the resonance-mode branching ratios, gives B({Omega}{sup -} {yields} {Xi}*{sub 1530}{sup 0} {pi}{sup -}) = [4.55 {+-} 2.33(stat) {+-} 0.38(syst)] x 10{sup -5}, B({Omega}{sup +} {yields} {ovr {Xi}*{sub 1530}{sup 0}}{pi}{sup +}) = [1.40 {+-} 2.83(stat) {+-} 0.12(syst)] x 10{sup -5} and disagrees with the current Particle Data Group review value, being {approx} 14 times smaller. Since the central value of the resonance-mode branching ratio is less than two standard deviations away from zero, we also calculate branching ratio upper limits at 90% confidence level: B({Omega}{sup -} {yields} {Xi}*{sub 1530}{sup 0} {pi}{sup -}) < 7.61 x 10{sup -5} and B({Omega}{sup +} {yields} {ovr {Xi}*{sub 1530}{sup 0}} {pi}{sup +}) < 5.61 x 10{sup -5}. This analysis provides new data on nonleptonic hyperon decays which allows studies of how weak interaction processes occur in the presence of strong interactions.
Date: December 1, 2007
Creator: Kamaev, Oleg
Partner: UNT Libraries Government Documents Department

Top quark results at CDF

Description: We present the latest results on the top quark obtained by the CDF experiment using a data sample of about 110 {ital pb}{sup -1} collected at the Fermilab Tevatron collider. We briefly describe the candidate events selection and then discuss the production cross section determination and the mass measurement. The study of two new decay channels (all hadronic and ``tau dilepton``) is also reported.
Date: August 1, 1996
Creator: Leone, S.
Partner: UNT Libraries Government Documents Department

Top production at D0

Description: We report an updated measurement of the top quark production cross section in {ital p}{ital {anti p}} collisions at {radical}s = 1.8 TeV by the D{null} experiment at the Fermilab Tevatron. We also present a measurement of the top quark mass. The data set used for these measurements corresponds to approximately 100 pb{sup -1}, almost the entire data sample collected by the D{null} experiment during the Run I of the Fermilab Tevatron. We observe 37 events with an expected background of 13.4{+-}3.0 events. We measure the mass of the top quark to be 170{+-}15({ital stat}){+-}10({ital syst.}) GeV/c{sup 2}. At this mass we find the top production cross section to be 5.2{+-}1. 8 pb.
Date: August 1, 1996
Creator: Narain, M.
Partner: UNT Libraries Government Documents Department

Top mass measurements at CDF

Description: We report on measurements of the top quark mass by the CDF experiment at the FermiLab Tevatron collider. The top quark is produced in {ital p{anti p}} collisions at {radical}{ital s} = 1.8 TeV. The analyses use an integrated luminosity of 110 pb{sup -1}. Results are presented from three decay channels, (i) one lepton plus jets, (ii) dilepton, (iii) all hadronic. The smallest error on the mass comes from (i), with a preliminary top mass value of 175.6 {+-}4.4 (stat.) {+-} 4.8 (syst.) GeV. Results from the other channels are consistent with this value.
Date: November 1, 1996
Creator: Lys, J.
Partner: UNT Libraries Government Documents Department

Top production at CDF

Description: We present the measurements of t{anti t} production cross section using {ital L} = 110 {ital pb{sup -1}} data sample of {ital p{anti p}} collisions at {radical}s = 1.8 TeV collected with the Collider Detector at Fermilab (CDF). Combining the results from the channels with at least one W decaying into leptons ({ital e} or {mu}) plus jets we measure {sigma}{sub t{anti t}} = 7.5 {sup +1.9}{sub -1.6} {ital pb}. We report the observation of t{anti t} production in all hadronic decay channels using a kinematical selection and b identification techniques. Finally we show preliminary evidence for t {anti t} production in the decay mode with one e or {mu} in the final state and a hadronically decaying {tau}.
Date: May 1, 1996
Creator: Azzi, P.
Partner: UNT Libraries Government Documents Department

Top quark physics at CDF

Description: We present preliminary results on top quark physics recently obtained by the CDF collaboration. The data sample consists of 110 {ital pb}{sup -1} of {ital p{anti p}} collisions at {radical}{ital s} = 1.8 TeV, collected with the Collider Detector at Fermilab during the period 1992 - 1995. We report on the {ital t{anti t}} production cross section and on the top quark mass. The measurements are made in three topologies, corresponding to the decay modes of the {ital Wb} pairs in the final state: lepton + multi-jets, dilepton and all hadronic final state. The analysis performed on the single lepton sample yields the most accurate measurements, due to the good acceptance and the favorable signal to noise ratio obtained after applying some b-tagging techniques. In this channel we measure: {sigma}{sub {ital t{anti t}}} = 6.8{sup +2.3}{sub -1.8} pb M{sub {ital t}} = 175.6 {+-} 5.7 ({ital stat}) {+-} 7.1 ({ital syst.}) {ital GeV/c{sup 2}} Combining the cross sections measured with the lepton + multi-jet and dilepton data we obtain: {sigma}{sub {ital t{anti t}}} = 7.5{sup +1.9}{sub -1.6} {ital pb} A preliminary investigation of the production mechanism of the {ital t{anti t}} system is shown and compared to Standard Model expectations.
Date: August 1, 1996
Creator: Caner, A.
Partner: UNT Libraries Government Documents Department

Measurement of the t tbar production cross section at D0

Description: We report on the results from the analyses of {ital t}{ital {anti t}} decays in {ital dilepton} and {ital lepton+jets} modes with {approx}100 pb{sup -1} of {ital p}{ital {anti p}} Collider data at {radical}s = 1.8 TeV collected by the D{null} experiment at the Fermilab Tevatron. We have observed 37 {ital t}{ital {anti t}} candidate events while the estimated background is 13.4 {+-} 3.0 events. The {ital t}{ital {anti t}} production cross section has been measured to be 5.2 {+-} 1.8 pb at a top quark mass of 170 GeV/c{sup 2}.
Date: August 1, 1996
Creator: Bhat, P.C.
Partner: UNT Libraries Government Documents Department

W/Z at CDF

Description: Results are presented based on 19 {ital pb}{sup -1} of data collected by the CDF detector during the 1992-1993 collider run at the Fermilab Tevatron. These results include measurements of the {ital W} mass and {sigma}{center_dot}{ital B} for {ital W} and {ital Z decays} using both the electron and muon channels. In addition to extracting the total width of the {ital W} width using the electron decay channel is also presented.
Date: August 1, 1996
Creator: Thurman-Keupp, R. M.
Partner: UNT Libraries Government Documents Department