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Meson phase space density from interferometry

Description: The interferometric analysis of meson correlations a measure of the average phase space density of the mesons in the final state. The quantity is a useful indicator of the statistical properties of the systems, and it can be extracted with a minimum of model assumptions. Values obtained from recent measurements are consistent with the thermal value, but do not rule out superradiance effects.
Date: December 31, 1993
Creator: Bertsch, G. F.
Partner: UNT Libraries Government Documents Department

Modeling mesons with relativistic wave equations

Description: We use two relativistic quasi-potential equations to fit meson spectra. A global fit of 45 mesons is achieved with an rams deviation from experiment of 43 MeV, and we compare meson two-photon decay widths calculated using the model wave functions with experimentally measured widths. We give an example calculation of in-medium (high temperature) effects that may be incorporated in the models.
Date: August 1, 1994
Creator: Sommerer, A. J.; El-Hady, A. A.; Spence, J. R.; Vary, J. P. & Benesh, C.
Partner: UNT Libraries Government Documents Department

Measurement of the average lifeetime of B hadrons at SLD

Description: The authors present preliminary measurements of the average B hadron lifetime using a sample of 50,000 Z{sup 0} events collected by SLD at the SLC in 1993. Their first technique uses the impact parameter of tracks in jets opposite tagged b jets. They obtain {tau}{sub B}({delta}) = 1.617 {+-} 0.048 {+-} 0.086 ps, and {tau}{sub B}({Sigma}{delta}) = 1.627 {+-} 0.054 {+-} 0.132 ps from single and summed impact parameter distributions. The second technique uses inclusive vertices reconstructed in three dimensions. From the decay length distribution, they extract {tau}{sub B} = 1.577 {+-} 0.032 {+-} 0.046 ps.
Date: September 1, 1994
Creator: Punkar, G.
Partner: UNT Libraries Government Documents Department

Proposal for the systematic naming of mesons and baryons

Description: Twenty years ago, the Particle Data Group adopted a systematic naming convention for baryons: the symbols N, ..delta.., ..lambda.., ..sigma.., ..xi.., and ..cap omega.. were to identify the isospin and strangeness, The mesons, by contrast, have become an alphabet soup of uninformative names - theta, iota, xi, zeta, g/sub T/, g/sub s/, H, E, delta, h, g, r, kappa, etc. -, and in some cases identical names are used for mesons with different quantum numbers (A, B, and D). Furthermore, experimentalists are now discovering baryons that contain heavy quarks. It is therefore timely to consider systematic naming conventions both for mesons and for baryons with heavy quarks. The Particle Data Group is circulating this proposal in the hope of generating feedback, and we attach a sheet for responses. It should be emphasized that the Particle Tables would show both the old and new names for some time.
Date: October 1, 1984
Creator: Porter, F.C.; Hernandez, J.J.; Montanet, L.; Roos, M.; Toernqvist, N.A.; Barnett, R.M. et al.
Partner: UNT Libraries Government Documents Department

New preliminary results on the physics of charm hadroproduction subprocesses

Description: This paper reviews the results and physics of two contributed papers to ICHEP94. Both papers relate to charm meson hadroproduction at Fermilab fixed target energies. The first (from E769) addresses the total forward cross section for charm mesons (D{sup {plus_minus}} and D{sub s}{sup {plus_minus}}) produced by {pi}{sup {plus_minus}}, K{sup {plus_minus}}, and proton beams. The second paper (from E791) deals with the asymmetries in the differential cross sections for charged D mesons produced in the forward direction by {pi}{sup {minus}} beam. The physics most directly related to the results of the E769 paper are the gluon distributions in the incident hadrons as well as perturbative QCD calculations of charm quark production and the charm quark mass. The E791 results address the details of the hadronization process after production of the charm quarks.
Date: October 1, 1994
Creator: Appel, J. A
Partner: UNT Libraries Government Documents Department

Phenomenology from 100 large lattices

Description: The authors present a status report on simulations being done on 32{sup 3} x 64 lattices at {beta} = 6.0 using quenched Wilson fermions. Phenomenologically relevant results for the spectrum, decay constants, the kaon B-parameter B{sub K}, B{sub 7}, B{sub s}, semi-leptonic and B {yields} K{sup *}{gamma} form factors are given based on a statistical sample of 100 configurations.
Date: February 1, 1995
Creator: Bhattacharya, T. & Gupta, R.
Partner: UNT Libraries Government Documents Department

J{sup P} = 1{sup {minus}} radial excitations from LASS data

Description: The experimental status of the strange 1 {sup {minus}} mesons is briefly reviewed and compared with the non-strange sector and quark model expectations. The results described are taken from a 4.1 event/nb exposure of the LASS spectrometer to an 11 GeV/e K{sup {minus}} beam.
Date: December 1, 1991
Creator: Aston, D.; Bienz, T.; Bird, F.; Dunwoodie, W.; Johnson, W. B.; Kunz, P. et al.
Partner: UNT Libraries Government Documents Department

On the scattering of atmospheric muons in the rock above Soudan 2

Description: I have investigated the effect of scattering in the rock overburden on the position and direction of atmospheric muons as observed at the Soudan 2 detector relative to the surface. The dominant contributions to the fluctuations in those observables arise from multiple Coulomb scattering and delta ray production. The contribution of the other energy loss mechanisms, bremsstrahlung, pair production and nuclear interactions, is small, with slowly increasing importance at very large deviations from the means of the distributions.
Date: January 24, 1992
Creator: Trost, Hans-Jochen
Partner: UNT Libraries Government Documents Department

Summary of the {eta}-meson sessions

Description: This summary describes the contents of the nineteen talks related to research on the {eta} meson and presented at the Workshop of Future Directions. The subjects of this area include threshold {eta} production, {eta}-nuclear spectroscopy, baryon spectroscopy, {eta} decays, facilities, and instrumentation.
Date: June 1, 1993
Creator: Chrien, R. E.
Partner: UNT Libraries Government Documents Department

Tests of non-local interferences in kaon physics at asymmetric {phi}-factories

Description: Tests of non-local interference effects in the two-kaon system are proposed. The first kind of tests consists of measuring the amount of destructive interference between K{sub S} {yields} K{sub L} regeneration processes of two distant kaons. The second kind deals with constructive interference. These tests could be performed at an asymmetric {phi}-factory. Estimates are given of the number of events predicted by orthodox quantum mechanics and kaon regeneration theory in various suitable experimental conditions. The impact on local theories if the predictions of quantum mechanics hold is discussed.
Date: April 16, 1993
Creator: Eberhard, P. H.
Partner: UNT Libraries Government Documents Department

Two Guage-Boson Physics at Very High Energies

Description: Use of rapidity-gap signature can lead to observation of interesting processes involving collisions of gauge-bosons at the SSC. This includes production of the heavy Higgs boson (500 GeV-1 TeV), which appears straightforward.
Date: May 1, 1992
Creator: Bjorken, J. D.
Partner: UNT Libraries Government Documents Department

Quenched QCD spectrum on a 32{sup 3} {times} 64 lattice

Description: We present light hadron masses calculated from quenched QCD on a 32{sup 3} {times} 64 lattice, using staggered quark sources of masses, m{sub q}a = 0.01,0.005 and 0.0025. Results from {beta} = 6. 0(preliminary) and those from {beta} = 6.5 are compared. Using m{sub p}(m{sub q} = 0) and f{sub {pi}}, we suggest that {beta} = 6.5 is in the asymptotic scaling region and {beta} = 6.0 result shows {approximately} 20% (bare coupling) or {approximately} 10% (improved coupling) scaling violation. Flavor symmetry appears to be restored at {beta} = 6.5. The estimated pion decay constant, f{sub {pi}}, is 93(4) MeV at {beta} = 6.5, where the experimental value is 93 MeV.
Date: November 1, 1993
Creator: Kim, S. & Sinclair, D. K.
Partner: UNT Libraries Government Documents Department

Goldstone pion and other mesons using a scalar confining interaction

Description: A covariant wave equation for q{bar q} interactions with an interaction kernel composed of the sum of constant vector and linear scalar confining interactions is solved for states with two quarks with identical mass. The model includes an NJL-like mechanism which links the dynamical breaking of chiral symmetry to the spontaneous generation of quark mass and the appearance of a low mass Goldstone pion. A novel feature of this approach is that it automatically explains the small mass of the pion even though the linear potential is a scalar interaction in Dirac space, and hence breaks chiral symmetry. Solutions for mesons composed of light quarks ({pi},{rho}, and low lying excited states) and heavy quarks ({rho}{sub c}, J/{Psi}, and low lying excited states) are presented and discussed.
Date: April 1, 1994
Creator: Gross, F. & Milana, J.
Partner: UNT Libraries Government Documents Department

Low energy theorems in pion production

Description: Considerable activity-both theoretical and experimental-has recently taken place involving the threshold and near threshold of pion photo- and electroproduction. This activity is herein summarized and a program for future work is outlined.
Date: September 1, 1992
Creator: Holstein, B. R.
Partner: UNT Libraries Government Documents Department

Inclusive charged hadron and K{sup 0} production in two-photon interactions

Description: The analogous process to quark pair production in e{sup +} e{sup {minus}} annihilation is the hard-scattering quark exchange process in {gamma}{gamma} interactions. This hard-scattering process is expected to dominate the cross section at high transverse momenta of the produced quarks. Experimentally, one has looked for this process in two-jet as well as inclusive particle production and has found a relatively low PT onset of hard scattering in {gamma}{gamma} interactions. This report examines the issue in more detail (high statistics) for charged particle inclusive production and checks if the heavier flavors display a similar behavior in inclusive K{sup 0} production.
Date: March 1, 1988
Creator: Cords, D.; Boyer, J.; Butler, F.; Gidal, G.; Abrams, G. S.; Amidei, D. et al.
Partner: UNT Libraries Government Documents Department

The off-shell axial anomaly via the {gamma}*{pi}{sup 0} {yields} {gamma} transition

Description: The {gamma}*{pi}{sup 0} {yields} {gamma} form factor, including the extension off the pion mass-shell, is obtained from a generalized impulse approximation within a QCD-based model field theory known to provide an excellent description of the pion charge form factor. This approach implements dressing of the vertex functions and propagators consistent with dynamical chiral symmetry breaking, gauge invariance, quark confinement and perturbative QCD. Soft nonperturbative behavior, dictated by the axial anomaly, is found to evolve to the perturbative QCD limit only for Q{sup 2} {ge} 20 GeV{sup 2}.
Date: January 1, 1995
Creator: Frank, M. R.; Mitchell, K. L.; Tandy, P. C. & Roberts, C. D.
Partner: UNT Libraries Government Documents Department

Signatures for hybrids

Description: In this review talk I summarize theoretical expectations for properties of hybrid mesons and baryons, and discuss the prospects for identifying these states experimentally.
Date: December 1, 1993
Creator: Barnes, T.
Partner: UNT Libraries Government Documents Department

Gauge invariance and the electromagnetic current of composite pions

Description: The Global Color-symmetry Model of QCD is extended to deal with a background electromagnetic field, and the associated conserved current is identified for the finite size {bar q}q pion modes at tree level. A well-defined truncation issued that factorizes the bilocal pion field into a local field variable and a hadronic form factor having a ladder Bethe-Salpeter content. The associated pion charge form factor is formulated. These developments are used to provide an illustration of how an effective hadronic action containing form factors may be electromagnetically coupled in a gauge invariant way that is accountable to its field substructure. In particular, the Ward-Takahashi identity for the photon vertex appropriate to the localized pion fields is seen to contain the hadronic form factors. In this context, gauge invariance of the effective hadronic action also requires recognition of the fact that the free inverse propagator for the localized pion field gauge transforms due to the substructure field content that has been absorbed into it.
Date: March 24, 1993
Creator: Frank, M. R. & Tandy, P. C.
Partner: UNT Libraries Government Documents Department

Elastic charge form factors for K mesons

Description: The elastic charge form factors for the charged K{sup +} and neutral K{sup 0} are presented. The model employed makes use of solutions of the coupled Bethe-Salpeter and Schwinger-Dyson equations. This covariant model, which provides good predictions for the pion`s elastic charge and transition form factor, has been presented elsewhere and will be briefly outlined here. The results for the kaon are in good agreement with the available data and can serve as an eventual guide in the interpretation of the approved CEBAF experiment E-93-018. The Q{sup 2} dependent K{sup 0} results suggest a new area for experimental exploration.
Date: April 1, 1994
Creator: Buck, W. W.; Williams, R. A. & Ito, Hiroshi
Partner: UNT Libraries Government Documents Department