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Differences between heavy and light quarks.

Description: The quark Dyson-Schwinger equation shows that there are distinct differences between light and heavy quarks. The dynamical mass function of the light quarks is characterized by a sharp increase below 1 GeV, whereas the mass function of the heavy quarks is approximately constant in this infrared region. As a consequence, the heavy meson masses increase linearly with the current quark masses, whereas the light pseudoscalar meson masses are proportional to the square root of the current quark masses.
Date: November 10, 1997
Creator: Maris, P. & Roberts, C. D.
Partner: UNT Libraries Government Documents Department

A Rosetta Stone Relating Conventions In Photo-Meson Partial Wave Analyses

Description: A new generation of complete experiments in pseudoscalar meson photo-production is being pursued at several laboratories. While new data are emerging, there is some confusion regarding definitions of asymmetries and the conventions used in partial wave analyses (PWA). We present expressions for constructing asymmetries as coordinate-system independent ratios of cross sections, along with the names used for these ratios by different PWA groups.
Date: April 1, 2012
Creator: A.M. Sandorfi, B. Dey, A. Sarantsev, L. Tiator, R. Workman
Partner: UNT Libraries Government Documents Department

Meson spectrum from the Bethe-Salpeter equation

Description: We present details of a model for calculating the mass spectrum of light-quark mesons and decay constants of the pseudoscalar meson octet from a phenomenological model based on Dyson-Schwinger and Bethe-Salpeter equations. In this model the Bethe-Salpeter kernel is approximated by a separable ansatz obtained from input quark propagators. 13 refs., 2 tabs.
Date: January 22, 1996
Creator: Burden, C. J.; Qian, L.; Tandy, P. C.; Roberts, C. D. & Thomson, M. J.
Partner: UNT Libraries Government Documents Department

High temperature meson propagators with domain-wall quarks.

Description: We study the chiral properties of domain-wall quarks at high temperatures on an ensemble of quenched configurations. Low lying eigenmodes of the Dirac operator are calculated and used to check the extent to which the Atiyah-Singer index theorem is obeyed on lattices with finite N{sub 5}. We calculate the connected and disconnected screening propagators for the lowest mass scalar and pseudoscalar mesons in the sectors of different topological charge and note that they behave as expected. Separating out the would-be zero eigenmodes enables us to accurately estimate the disconnected propagators with far less effort than would be needed otherwise.
Date: September 23, 1999
Creator: Lagae, J.-F. & Sinclair, D. K.
Partner: UNT Libraries Government Documents Department

Search for rare 3 and 4-body D0 decays at FNAL E791

Description: Limits at the 10{sup -4} level are reported for rare and forbidden decays of the D{sup 0} charm meson to a pair of leptons and either a vector meson or two pseudoscalar mesons. Of these searches, 18 are investigations of decays without previous published results; several others have significantly improved sensitivity over previous results.
Date: June 12, 2001
Creator: Summers, Donald J.
Partner: UNT Libraries Government Documents Department

Exact heavy to light meson form factors in the combined heavy quark, large N{sub c} and chiral limits

Description: We demonstrate that the form factors of local operators between a heavy meson state (like the B) and a light pseudoscalar state (like the pion) are given exactly by a single pole form in the combined heavy quark, large N{sub c} (number of colors) and chiral limits. We discuss the deviations from this exact result from finite heavy quark masses, non-zero light quark masses and finite N{sub c}. We comment on some of the numerous implications of this result.
Date: December 1, 1993
Creator: Grinstein, B. & Mende, P.
Partner: UNT Libraries Government Documents Department

Search for Lepton Flavor Violating Decays $\tau^\pm \to \ell^\pm{\pi^0}, \ell^\pm\eta, \ell^\pm{\eta^\prime}$

Description: A search for lepton flavor violating decays of the {tau} lepton to a lighter mass lepton and a pseudoscalar meson has been performed using 339 fb{sup -1} of e{sup +}e{sup -} annihilation data collected at a center-of-mass energy near 10.58GeV by the BABAR detector at the SLAC PEP-II storage ring. No evidence of signal has been found, and upper limits on the branching fractions are set at 10{sup -7} level.
Date: November 15, 2006
Creator: Aubert, B.
Partner: UNT Libraries Government Documents Department

Semirelativistic constituent-quark model with goldstone-boson-exchange hyperfine interactions.

Description: We address the semirelativistic constituent-quark model with linear confinement and a hyperfine interaction deduced from Goldstone-boson exchange. In the version where the latter is represented by pseudoscalar meson exchange ({pi}, K, {eta}, {eta}{prime})and restricted to the spin-spin component only a unified description of all light- and strange-baryon spectra is provided in close agreement with phenomenology. We discuss the extension of the model that includes also the tensor components of the pseudoscalar meson exchange and in addition vector-meson ({rho}, {omega}, K*, {phi}) and scalar-meson ({sigma}) exchanges. A preliminary version thereof provides a description of the baryon spectra with similar good quality.
Date: October 20, 1998
Creator: Wagenbrunn, R. F.
Partner: UNT Libraries Government Documents Department

Decay constants of heavy-light pseudoscalars: Results at {beta} = 6.3

Description: A lattice calculation of the pseudoscalar decay constant for heavy-light mesons is reported. Emphasis is placed on preliminary results obtained using wall-source propagators at {beta} = 6.3. The previously-observed discrepancy between the static and conventional approaches appears to be much reduced.
Date: January 1, 1992
Creator: Bernard, C.; Heard, C. M.; Labrenz, J. & Soni, A.
Partner: UNT Libraries Government Documents Department

Physics Prospects with GlueX

Description: The new experiment GlueX is being currently constructed at Jefferson Lab. The experiment was designed to search for hybrid mesons with exotic-quantum-numbers using a beam of linearly polarized photons incident on a liquid hydrogen target. We will discuss the discovery potential of the GlueX experiment and briefly overview its physics program. GlueX is a new experiment at Jefferson Lab. whose physics program is intended to improve our knowledge of strong interactions. The main goal of the experiment is to search for gluonic excitations in photoproduction. The experiment is expected to collect a data sample a few order of magnitudes larger than all existing photoproduction data. The physics topics of the experiment spans from light meson spectroscopy to Primakoff production of pseudoscalar mesons. The construction of the experiment has started in 2009 and the commissioning stage is expected to be finished in 2015.
Date: October 1, 2011
Creator: Somov, Alexander
Partner: UNT Libraries Government Documents Department

Observation of B to eta' K* and Evidence for B+ to eta' rho+

Description: The authors presented an observation of B {yields} {eta}{prime}K*. The data sample corresponds to 232 million B{bar B} pairs collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. They measure the branching fractions (in units of 10{sup -6}) {Beta}(B{sup 0} {yields} {eta}{prime}K*{sup 0}) = 3.8 {+-} 1.1 {+-} 0.5 and {Beta}(B{sup +} {yields} {eta}{prime}K*{sup +}) = 4.9{sub -1.7}{sup +1.9} {+-} 0.8, where the first error is statistical and the second systematic. A simultaneous fit results in the observation of B {yields} {eta}{prime}K* with {Beta}(B {yields} {eta}{prime}K*) = 4.1{sub -0.9}{sup +1.0} {+-} 0.5. They also search for B {yields} {eta}{prime}{rho} and {eta}{prime} f{sub 0}(980)(f{sub 0} {yields} {pi}{sup +}{pi}{sup -}) with results and 90% confidence level upper limits {Beta}(B{sup +} {yields} {eta}{prime}{rho}{sup +}) = 8.7{sub -2.8-1.3}{sup +3.1+2.3} (< 14), {Beta}(B{sup 0} {yields} {eta}{prime}{rho}{sup 0}) < 3.7, and {Beta}(B{sup 0} {yields} {eta}{prime} f{sub 0}(980)(f{sub 0} {yields} {pi}{sup +}{pi}{sup -})) < 1.5. Charge asymmetries in the channels with significant yields are consistent with zero.
Date: September 26, 2006
Creator: Aubert, B
Partner: UNT Libraries Government Documents Department

The kaon B-parameter from unquenched mixed action lattice QCD

Description: We present a preliminary calculation of B{sub K} using domain-wall valence quarks and 2+1 flavors of improved staggered sea quarks. Both the size of the residual quark mass, which measures the amount of chiral symmetry breaking, and of the mixed meson splitting Delta{sub mix}, a measure of taste-symmetry breaking, show that discretization effects are under control in our mixed action lattice simulations. We show preliminary data for pseudoscalar meson masses, decay constants and B{sub K}. We discuss general issues associated with the chiral extrapolation of lattice data, and, as an example, present a preliminary chiral and continuum extrapolation of f{sub pi}. The quality of our data shows that the good chiral properties of domain-wall quarks, in combination with the light sea quark masses and multiple lattice spacings available with the MILC staggered configurations, will allow for a precise determination of B{sub K}.
Date: October 1, 2007
Creator: Aubin, Christopher A.; Laiho, Jack & Van de Water, Ruth S.
Partner: UNT Libraries Government Documents Department

Minimal Doubling and Point Splitting

Description: Minimally-doubled chiral fermions have the unusual property of a single local field creating two fermionic species. Spreading the field over hypercubes allows construction of combinations that isolate specific modes. Combining these fields into bilinears produces meson fields of specific quantum numbers. Minimally-doubled fermion actions present the possibility of fast simulations while maintaining one exact chiral symmetry. They do, however, introduce some peculiar aspects. An explicit breaking of hyper-cubic symmetry allows additional counter-terms to appear in the renormalization. While a single field creates two different species, spreading this field over nearby sites allows isolation of specific states and the construction of physical meson operators. Finally, lattice artifacts break isospin and give two of the three pseudoscalar mesons an additional contribution to their mass. Depending on the sign of this mass splitting, one can either have a traditional Goldstone pseudoscalar meson or a parity breaking Aoki-like phase.
Date: June 14, 2010
Creator: Creutz, M.
Partner: UNT Libraries Government Documents Department

Decays of neutral pseudoscalar mesons into lepton pairs

Description: The authors calculate the branching ratio {Lambda}(P {yields} {ell}{sup +}{ell}{sup -})/{Lambda}(P {yields} {gamma}{gamma}) to lowest contributing order in quantum electrodynamics, with a vector meson model for the pseudoscalar meson form factor. They treat the processes {eta} {yields} {mu}{sup +}{mu}{sup -}; {eta} {yields} e{sup +}e{sup -}; K{sub 2}{sup 0} {yields} {mu}{sup +}{mu}{sup -}; K{sub 2}{sup 0} {yields} e{sup +}e{sup -}; {pi}{sup 0} {yields} e{sup +}e{sup -}. Results are compared with those of previous calculations.
Date: September 24, 1968
Creator: Quigg, C. & Jackson, J. D.
Partner: UNT Libraries Government Documents Department

Apiary B Factory lattice design

Description: The Apiary B Factory is a proposed high-intensity electron-positron collider. This paper will present the lattice design for this facility, which envisions two rings with unequal energies in the PEP tunnel. The design has many interesting optical and geometrical features due to the needs to conform to the existing tunnel, and to achieve the necessary emittances, damping times and vacuum. Existing hardware is used to a maximum extent. 8 figs. 1 tab.
Date: April 1, 1991
Creator: Donald, M.H.R. (Stanford Linear Accelerator Center, Menlo Park, CA (USA)) & Garren, A.A. (Lawrence Berkeley Lab., CA (USA))
Partner: UNT Libraries Government Documents Department

Preliminary measurement of prompt D{sup {+-}} and D*{sup {+-}} meson production and D*{sup {+-}} spin alignment in hadronic Z{sup 0} decays

Description: The authors have measured the production rates as a function of scaled energy x of prompt charmed pseudoscalar D{sup {+-}} and vector D*{sup {+-}} mesons in hadronic Z{sup 0} decays. The prompt signal components were isolated from the background of D mesons from B hadron decays using impact parameters of reconstructed D{sup {+-}} {yields} K{sup {minus_plus}}{pi}{sup {+-}}{pi}{sup {+-}} and D*-daughter D{sup 0} {yields} K{sup {minus}}{pi}{sup +} and D{sup 0} {yields} K{sup {minus}}{pi}{sup +}{pi}{sup {minus}}{pi}{sup +} candidates. Using the combined meson production rates the authors have measured the fraction of hadronic Z{sup 0} decays into c{bar c}, R{sub c} = 0.182 {+-} 0.027 (stat.) {+-} 0.012 (syst.) (Preliminary). Comparison of the D*{sup {+-}} and D{sup {+-}} rates gives a direct probe of vector (V) vs. pseudoscalar (P) meson production for charmed quarks, and for x > 0.4 they have measured P{sub V} = V/(V + P) = 0.65 {+-} 0.09(stat.) {+-} 0.03(syst.) {+-} 0.03 (BR) (Preliminary). They have measured the degree of spin alignment of the D*{sup {+-}} mesons along their flight direction and find it to be consistent with zero. They compared the latter two results with QCD- and model-based predictions of charm-quark jet fragmentation.
Date: June 1, 1997
Creator: Abe, K.; Abe, K.; Akagi, T. & Collaboration, SLD
Partner: UNT Libraries Government Documents Department

Pseudoscalar meson electroproduction above the resonance region

Description: One principal motivation for studying exclusive reactions is that they provide a new class of observables, called off-diagonal parton distributions, for the internal structure of the nucleon. The study of exclusive reactions provides a probe of nucleon structure complementary to purely inclusive studies. The simplest, and possibly the most promising, type of experiment is exclusive electroproduction of pseudoscalar mesons at small t, and at large Q{sup 2} and W. The authors show that using the CLAS spectrometer at JLAB and with beam energies between four and six GeV, they can obtain good quality electroproduction data that will improve their understanding of nucleon structure.
Date: April 1, 1999
Creator: Niczyporuk, B.B.
Partner: UNT Libraries Government Documents Department

B decays into light mesons

Description: The author calculates the form factors describing semileptonic and penguin induced decays of B mesons into light pseudoscalar and vector mesons. The form factors are calculated from QCD sum rules on the light-cone including contributions up to twist 4, radiative corrections to the leading twist contribution and SU(3) breaking effects. The theoretical uncertainty is estimated to be tilde (15--20)%.
Date: April 1, 1998
Creator: Ball, P.
Partner: UNT Libraries Government Documents Department

Unquenched Studies Using the Truncated Determinant Algorithm

Description: A truncated determinant algorithm is used to study the physical effects of the quark eigenmodes associated with eigenvalues below 420 MeV. This initial high statistics study focuses on coarse (6{sup 4}) lattices (with O(a{sup 2}) improved gauge action), light internal quark masses and large physical volumes. Three features of full QCD are examined: topological charge distributions, string breaking as observed in the static energy and the eta prime mass.
Date: November 29, 2001
Creator: A. Duncan, E. Eichten and H. Thacker
Partner: UNT Libraries Government Documents Department

Two-colour QCD at finite fundamental quark-number density and related theories

Description: We are simulating SU(2) Yang-Mills theory with four flavours of dynamical quarks in the fundamental representation of SU(2) colour at finite chemical potential, p for quark number, as a model for QCD at finite baryon number density. In particular we observe that for p large enough this theory undergoes a phase transition to a state with a diquark condensate which breaks quark-number symmetry. In this phase we examine the spectrum of light scalar and pseudoscalar bosons and see evidence for the Goldstone boson associated with this spontaneous symmetry breaking. This theory is closely related to QCD at finite chemical potential for isospin, a theory which we are now studying for SU(3) colour.
Date: November 15, 2000
Creator: Hands, S. J.; Kogut, J. B.; Morrison, S. E. & Sinclair, D. K.
Partner: UNT Libraries Government Documents Department

Separable approximation to the Bethe-Salpeter equation in QCD

Description: We calculate the mass spectrum and decay constants of the pseudoscalar meson octet, and mass spectrum of the vector meson octet from a separable approximation to the Bethel-Salpeter equation. In the model, quark propagators inspired by earlier studies of QCD Dyson-Schwinger equations are taken as the only input.
Date: December 1, 1995
Creator: Burden, C.J.; Qian, L. & Roberts, C.D.
Partner: UNT Libraries Government Documents Department

A meson exchange model for the YN interaction

Description: We present a new model for the hyperon-nucleon (Lambda N, Sigma N) interaction, derived within the meson exchange framework. The model incorporates the standard one boson exchange contributions of the lowest pseudoscalar and vector meson multiplets with coupling constants fixed by SU(6) symmetry relations. In addition - as the main feature of the new model - the exchange of two correlated pions or kaons, both in the scalar-isoscalar (sigma) and vector-isovector (rho) channels, is included.
Date: September 1, 2001
Creator: Haidenbauer, J.; Melnitchouk, W. & Speth, J.
Partner: UNT Libraries Government Documents Department

Rare and forbidden decays of D Mesons

Description: The authors summarize the results of two recent searches for flavor-changing neutral current, lepton-flavor violating, and lepton-number violating decays of D{sup +}, D{sub s}{sup +}, and D{sup 0} mesons (and their antiparticles) into modes containing muons and electrons. using data from Fermilab charm hadroproduction experiment E791, they examined D{sup +} and D{sub s}{sup +} {pi}{ell}{ell} and {Kappa}{ell}{ell} decay modes and the D{sup 0} dilepton decay modes containing either {ell}{sup +}{ell}{sup {minus}}, a {rho}{sup 0}, {bar {Kappa}}*{sup 0}, or {phi} vector meson, or a non-resonant {pi}{pi}, {Kappa}{pi}, or {Kappa}{Kappa} pair of pseudoscalar mesons. No evidence for any of these decays was found. Therefore, the authors presented branching-fraction upper limits at 90% confidence level for the 51 decay modes examined. Twenty-six of these modes had no previously reported limits, and eighteen of the remainder were reported with significant improvements over previously published results.
Date: May 23, 2001
Creator: al., David A. Sanders et
Partner: UNT Libraries Government Documents Department

Composite Octet Searches with Jet Substructure

Description: Many new physics models with strongly interacting sectors predict a mass hierarchy between the lightest vector meson and the lightest pseudoscalar mesons. We examine the power of jet substructure tools to extend the 7 TeV LHC sensitivity to these new states for the case of QCD octet mesons, considering both two gluon and two b-jet decay modes for the pseudoscalar mesons. We develop both a simple dijet search using only the jet mass and a more sophisticated jet substructure analysis, both of which can discover the composite octets in a dijet-like signature. The reach depends on the mass hierarchy between the vector and pseudoscalar mesons. We find that for the pseudoscalar-to-vector meson mass ratio below approximately 0.2 the simple jet mass analysis provides the best discovery limit; for a ratio between 0.2 and the QCD-like value of 0.3, the sophisticated jet substructure analysis has the best discovery potential; for a ratio above approximately 0.3, the standard four-jet analysis is more suitable.
Date: February 14, 2012
Creator: Bai, Yang; /SLAC; Shelton, Jessie & U., /Yale
Partner: UNT Libraries Government Documents Department