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Scalar and tensor couplings in kaon decays

Description: In the past few years charged kaon experiments have indicated possible scalar and tensor couplings in semileptonic kaon decays (K{yields}{pi}e{nu}). These couplings, if correct, are not predicted by the Standard Model and may indicate the onset of new physics. We present a summary of the existing data and a new, precision measurement of these couplings in the neutral kaon system based on a 3% subset of the data taken by the KTeV (E799) experiment at Fermilab.
Date: May 10, 1999
Creator: Tesarek, Richard J.
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

b {r_arrow} sl{sup +}l{sup {minus}} in the left-right symmetric model

Description: We begin to analyze and contrast the predictions for the decay b {r_arrow} sl{sup +}l{sup {minus}} in the Left-Right Symmetric Model (LMR) with those of the Standard Model (SM). In particular, we show that the forward-backward asymmetry of the lepton spectrum can be used to distinguish the SM from the simplest manifestation of the LRM.
Date: May 1, 1997
Creator: Rizzo, T.G.
Partner: UNT Libraries Government Documents Department

Estimated Errors in |Vcd|/|Vcs| from semileptonic D decays

Description: We estimate statistical and systematic errors in the extraction of the CKM ratio {vert_bar}V{sub cd}{vert_bar}/{vert_bar}v{sub cs}{vert_bar} from exclusive D-meson semileptonic decays using lattice QCD and anticipated new experimental results.
Date: November 1, 1998
Creator: J.N.Simone, A.X.El-Khadra, S.Hashimoto, A.S.Kronfeld, P.B.Mackenzie, and S.M.Ryan
Partner: UNT Libraries Government Documents Department

Observation of the Decay K{sup +} yields P{sup +} v...

Description: We have observed 1 event consistent with the signature expected of the rare decay of a positive kaon to a positive pion and a neutrino anti-neutrino pair. In the examined momentum region of 211 to 230 MeV/c in the center of mass of the kaon we estimated the backgrounds to be about 0.08 &plusmn; 0.03 events. From this observation we estimate the branching ratio to be 4.2<SUP>+9.7</SUP><SUB>-3.5</SUB> x 10<SUP>-10</SUP>. In this presentation I will explain the experiment, and the analysis techniques. I will also discuss the expected improvements in the near future from the analysis of new data sets.
Date: May 21, 1999
Creator: Diwan, M.V.
Partner: UNT Libraries Government Documents Department

1/m<sub>c</sub> Terms in lambda<sup>+</sup><sub>c</sub> Semileptonic Decays

Description: We use the heavy quark effective theory to investigate the form factors that describe the semileptonic decays lambda<sup>+</sup><sub>c</sub> -> lambda e<sup>+</sup> nu, to order 1/m<sub>c</sub>. We find that a total of four form factors are needed to this order, in contrast with two form factors to leading order, and six form factors in the most general case. We point out some relationships that arise among the general form factors.
Date: February 1, 1992
Creator: Roberts, Winston
Partner: UNT Libraries Government Documents Department

Rare kaon decays

Description: The phenomenology of rare kaon decays is reviewed, with emphasis on tests of standard model flavordynamics.
Date: January 1, 1997
Creator: Buchalla, G.
Partner: UNT Libraries Government Documents Department

Evidence for {Kappa}{sup +} {r_arrow} {pi}{sup +}{nu}{anti {nu}}

Description: The first observation of the decay {Kappa}{sup +} {r_arrow} {pi}{sup +}{nu}{anti {nu}} has been reported. The E787 experiment presented evidence for the {Kappa}{sup +} {r_arrow} {pi}{sup +}{nu}{anti {nu}} decay, based on the observation of a single clean event from data collected during the 1995 run of the AGS (Alternating Gradient Synchrotron at Brookhaven National Laboratory). The branching ratio indicated by this observation, {Beta}({Kappa}{sup +} {r_arrow} {pi}{sup +}{nu}{anti {nu}}) = 4.2{sub {minus}3.5}{sup +9.7} {times} 10{sup {minus}10}, is consistent with the Standard Model expectation although the central experimental value is four times larger. The final E787 data sample, from the 1995--98 runs, should reach a sensitivity of about five times that of the 1995 run alone. A new experiment, E949, has been given scientific approval and should start data collection in 2001. It is expected to achieve a sensitivity of more than an order of magnitude below the prediction of the Standard Model.
Date: December 31, 1998
Creator: Kettell, S.
Partner: UNT Libraries Government Documents Department

Probing supersymmetry in rare B decays

Description: We determine the ability of future experiments to observe supersymmetric contributions to the rare decays B {r_arrow} X{sub s}{gamma} and B {r_arrow} X{sub s}l{sup +}l{sup -}. A global fit to the Wilson coefficients which contribute to these decays is performed from Monte Carlo generated data. This fit is then compared to supersymmetric predictions for several different patterns of the superpartner spectrum.
Date: October 1, 1996
Creator: Hewett, J.L.
Partner: UNT Libraries Government Documents Department

A measurement of the b quark fragmentation function at {radical}Q{sup 2} = 45.6 GeV

Description: Presented here is a measurement of the b quark fragmentation function D{sub b}(X), taken from a sample of 504 semi-leptonic B decays which were selected from the 150,000 Z{sup 0} decays collected between 1993 and 1995 at the SLD at SLAC. The energy of each tagged B hadron is reconstructed using missing jet energy, based on the information from the lepton and a partially-reconstructed charm-decay vertex. Account is taken of the effect of primary orbitally excited mesons (B**s). An iterative unfolding procedure is used which serves to effectively extract the true fragmentation function from the reconstructed B energy spectrum. The final result is shown to be compatible with many theoretical models. A comparison is made with other b fragmentation function measurements at 45.6 GeV, and this measurement is shown to be consistent with those results. The average scaled energy is found to be (x{sub E}) = 0.697{+-} 0.017(stat) {+-} 0.034(sys).
Date: June 1, 1996
Creator: Church, E.D.
Partner: UNT Libraries Government Documents Department

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

Search for new mechanism of CP violation through tau decay and semileptonic decay at hadrons

Description: If CP is violated in any decay process involving leptons it will signify the existence of a new force (called the X boson) responsible for CP violation that may be the key to understanding matter-antimatter asymmetry in the universe. The author discusses the signatures of CP violation in (1) the decay of tau lepton, and (2) the semileptonic decay of {pi}, K, D, B and t particles by measuring the polarization of the charged lepton in the decay. The author discusses how the coupling constants and their phases of the coupling of the X boson to 9 quark vertices and 3 lepton vertices can be obtained through 12 decay processes.
Date: November 1, 1996
Creator: Tsai, Yung Su
Partner: UNT Libraries Government Documents Department

Lepton flavor violation

Description: The connection of rare decays to supersymmetric grand unification is highlighted, and a review of the status of rare decay experiments is given. Plans for future investigations of processes that violate lepton flavor are discussed. A new result from the MEGA experiment, a search for {mu}{sup +} {yields} e{sup +} {gamma}, is reported to be B.R. < 3.8 x 10{sup -11} with 90% confidence.
Date: October 1, 1997
Creator: Cooper, M.D. Brooks, M. & Hogan, G.E.
Partner: UNT Libraries Government Documents Department

919: Evidence for K{sup +} {r_arrow} {pi}{sup +} {nu}{bar {nu}} from E787

Description: A collaboration from KEK, INS, Osaka, TRIUMF, Princeton, and BNL is currently running E787 at the AGS. The experiment is designed primarily to search for the rare decay K{sup +} {yields} {pi}{sup +}{nu}{bar {nu}}, with an expected branching ratio of {approximately} 10{sup {minus}10}. The authors report evidence that they have observed this decay. They also discuss the future outlook for the experiment.
Date: December 1, 1997
Creator: Frank, J.S. & Collaboration, E787
Partner: UNT Libraries Government Documents Department

From symmetry violation to dynamics: The charm window

Description: C.S. Wu observed parity violation in the low energy process of nuclear decay. She was the first to observe this symmetry violation at any energy. Yet, her work taught us about the form and strengths of the couplings of the massive weak boson. Today, we use the same approach. We look for very much higher mass-scale interactions through symmetry violations in the decays of charm quark systems. These charm decays provide a unique window to new physics.
Date: December 1, 1997
Creator: Appel, J.A.
Partner: UNT Libraries Government Documents Department

The K{sub L} {yields} {pi}{sup 0}{nu}{anti {nu}} decay beyond the Standard Model

Description: The K{sub L} {yields} {pi}{sup 0}{nu}{anti {nu}} decay is analyzed in a model independent way. When lepton flavor is conserved, this decay mode is a manifestation of CP violating interference between mixing and decay. Consequently, a theoretically clean relation between the measured rate and electroweak parameters holds in any given model.
Date: April 1, 1997
Creator: Grossman, Y.
Partner: UNT Libraries Government Documents Department

Unified description of kaon electroweak form factors

Description: A calculation of the semileptonic decays of the kaon (K{sub l3}) is presented. The results are direct predictions of a covariant model of the pion and kaon introduced earlier by Ito, Buck, Gross. The weak form factors for K{sub l3} are predicted with absolutely no parameter adjustments of the model. The authors obtained for the form factor parameters: f{sub {minus}}(q{sup 2}=m{sub l}{sup 2})/f{sub +}(q{sup 2}=m{sub l}{sup 2})={minus}0.28 and {lambda}{sub +}= 0.028, both within experimental error bars. Connections of this approach to heavy quark symmetry will also be discussed.
Date: June 1, 1996
Creator: Afanasev, A. & Buck, W.
Partner: UNT Libraries Government Documents Department

Form factors of kaon semileptonic decays

Description: A calculation of the semi-leptonic decays of the kaon (K{sub 13}) is presented. The results are direct predictions of a covariant model of the pion and kaon introduced earlier by Ito, Buck, and Gross. The weak form factors for K{sub 13} are predicted with absolutely no parameter adjustments of the model. The authors obtained for the form factor parameters: f{sub {minus}}(q{sup 2} = m{sub 1}{sup 2})/f{sub +}(q{sup 2} = m{sub 1}{sup 2}) = 0.28 and {lambda}{sub +} = 0.028, both within experimental error bars. Connections of this approach to heavy quark symmetry is also discussed.
Date: July 1, 1996
Creator: Afanasev, Andrei & Buck, W.W.
Partner: UNT Libraries Government Documents Department

Semileptonic meson decays in the quark model: An update

Description: The authors present the predictions of ISGW2, an update of the ISGW quark model for semileptonic meson decays. The updated model incorporates a number of features which should make it more reliable, including the constraints imposed by Heavy Quark Symmetry, hyperfine distortions of wave-functions, and form factors with more realistic high recoil behaviors.
Date: March 1, 1995
Creator: Scora, D. & Isgur, N.
Partner: UNT Libraries Government Documents Department

Tevatron results on gauge boson couplings

Description: Direct measurements of the trilinear gauge boson couplings by the CDF and D0 collaborations at Fermilab are reviewed. Limits on the anomalous couplings were obtained at a 95% CL from four diboson production processes: W{gamma} production with the subsequent W boson decay to e{nu} or {mu}{nu}, WW production with both the W boson decaying to e{nu} or {mu}{nu}, WW/WZ production with one of the gauge bosons decaying leptonically and the other gauge boson decaying to two jets, and Z{gamma} production with the subsequent Z boson decay to ee, {mu}{mu}, or {nu}{nu}. Limits were also obtained by a combined fit to W{gamma}, WW{yields}dileptons and WW/WZ semileptonic data samples.
Date: June 1, 1997
Creator: Yasuda, T. & Collaborations, CDF and D0
Partner: UNT Libraries Government Documents Department

On constraints for heavy-meson form factors

Description: We examine the recent work of de Rafael and Taron where model-independent bounds on the Isgur-Wise function are presented. We first argue that the bounds cannot hold in as much generality as implied. We show that the effects of resonances omitted in their discussion (such as heavy-heavy ``onium`` states below threshold) modify the bound. The resulting bound is much weaker but may be useful where the size of the additional contribution may be computed or estimated.
Date: November 1, 1992
Creator: Grinstein, B. & Mende, P.F.
Partner: UNT Libraries Government Documents Department

A kaon physics program at the Fermialb Main Injector

Description: In this paper we describe a triad of kaon experiments which will form the foundation of a kaon physics program at Fermilab in the Main Injector era. These three experiments; KAMI, CKM and CPT, span the range of experiment types discussed above. KAMI will use the existing neutral kaon beam and the KTeV detector as the basis of a search for the Standard Model ultra rare decay K{sub L} {yields} {pi}{sup 0}{nu}{anti {nu}} decay mode is by far the theoretically cleanest measurement of the Standard Model parameter responsible for CP violation. CKM will measure the analogous charged kaon decay mode. Together these two experiments will determine the Standard Model contribution to CP violation independent of the B meson sector. The Standard Model parameters controlling CP violation must be observed to be the same in the K and B meson sectors in order to confirm the Standard Model as the sole source of CP violation in nature. CPT is a hybrid beam experiment using a high purity K{sup +} beam to produce a pure K{sub 0} beam in order to search for violation of CPT symmetry at a mass scale up to the Planck mass. CPT also will measure new CP violation parameters to test the Standard Model and search for rare K{sub S} decays. The Fermilab infrastructure for such a physics program largely already exists. The Main Injector will be an existing accelerator by late 1998 with beam properties comparable to any of the previous ``kaon factory`` proposals. The KTeV detector and neutral kaon beamline are unsurpassed in the world and were originally designed to also operate with the 120 GeV Main Injector beam as KAMI. The Fermilab Meson laboratory was originally designed as an area for fixed target experiments using 200 GeV proton beams. The charged kaon beam experiments ...
Date: November 1, 1997
Creator: Cooper, Peter
Partner: UNT Libraries Government Documents Department