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Onium and b production at the Tevatron

Description: Recent data from the CDF and D0 experiments at the Tevatron are presented on b quark production cross sections, J/{psi}, {psi}{prime} and {Upsilon} production cross sections. An analysis from CDF of the production polarization of the J/{psi}, {psi}{prime} and {Upsilon}(1S) is reviewed and the results discussed in the context of the color octet model.
Date: January 27, 2000
Creator: Sumorok, K.
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

{psi}{prime} and J/{psi} suppression in high-energy nucleon-nucleus and nucleus-nucleus collisions

Description: The observed features of {psi}` to J/{psi} suppression in pA and nucleus-nucleus collisions can be explained in terms of a two-component absorption model. For the hard component of the absorption due to the interaction of the produced c{bar c} systems with baryons at high relative energies, the absorption cross sections are insensitive to the radii of the c{bar c} systems, as described by the Additive Quark Model. For the soft component due to the low energy c{bar c} interactions with soft particles produced by other baryon-baryon collisions, the absorption cross sections are greater for {psi}` than for J/{psi}, because the breakup threshold for {psi}` is much smaller than for {psi}.
Date: December 31, 1995
Creator: Wong, Cheuk-Yin
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

Rapidity dependence of the inclusive J/{psi} production in p{bar p} collisions at {radical}s = 1.8 TeV

Description: We have studied the {ital J}/{psi} production in {ital p}{ital {anti p}} collisions at {radical}s = 1.8 TeV with the D{null} detector at the Fermilab Tevatron, using a {mu}{sup +}{mu}{sup -} data sample collected during the 1994-95 running period. We have measured the inclusive {ital J}/{psi} production cross section as a function of the {ital J}/{psi} transverse momentum, {ital P}{sub T}{sup {ital J}/{psi}} in the central and forward rapidity regions. The new measurement of the cross section {ital d{sigma}/dp}{sub T}{sup {ital J}/{psi}} for {vert_bar}{eta}{sup {ital J}/{psi}}{vert_bar} {lt} 0.6 is in a good agreement with the CDF and earlier D{null} results. The cross section measurement {ital d{sigma}/dp}{sub T}{sup {ital J}/{psi}} for 2.5 {lt} {vert_bar}{eta}{sup {ital J}/{psi}}{vert_bar} {lt} 3.7 covers the {ital p}{sub T}{sup {ital J}/{psi}} range from 1 to 16 GeV/c. We combine the measurements in several {vert_bar}{eta}{sup {ital J}/{psi}}{vert_bar} regions to discuss {ital d{sigma}/d{eta}}{sup {ital J}/{psi}} for {ital p}{sub T}{sup {ital J}/{psi}} {gt} 8 GeV/c. The data are compared with the next-to- leading order (NLO) QCD calculations, which take into account different {ital J}/{psi} production mechanisms.
Date: August 1, 1996
Creator: D0 Collaboration
Partner: UNT Libraries Government Documents Department

J/{Psi} suppression as a signal for the quark-gluon plasma

Description: The authors review the search for the quark-gluon plasma using the signal of the suppression of J/{psi} production in high-energy heavy-ion collisions. Recent anomalous J/{psi} suppression in high-energy Pb-Pb collisions observed by the NA50 Collaboration are examined and compared with earlier results from pA and nucleus-nucleus collisions with heavy ions of smaller mass numbers. The anomalous suppression of J/{psi} production in Pb-Pb collisions can be explained as due to the occurrence of a new phase of strong J/{psi} absorption, which sets in when the number of nucleon-nucleon collisions at a spatial point exceeds about 4 and corresponds to a local energy density of about 3.4 GeV/fm{sup 3}.
Date: December 1, 1997
Creator: Wong, C.Y.
Partner: UNT Libraries Government Documents Department

Unresolved questions in J/{psi} production and propagation in nuclei

Description: In order to understand the J/{psi} suppression arising from the possible occurrence of the quark-gluon plasma in high-energy heavy-ion collisions, it is necessary to have a comprehensive picture how the J/{psi} and its precursors are produced, what their properties after production are, and how the J/{psi} and its precursors propagate inside nuclear matter. There are unresolved questions in the descriptions of J/{psi} production and propagation. The author outlines some of these questions and discusses the approaches for their resolution.
Date: November 1, 1998
Creator: Wong, C.Y.
Partner: UNT Libraries Government Documents Department

The magnitude of the gluon condensate and the masses of c and b quarks from the families of T/{Psi} and {Upsilon} mesons

Description: It is shown that the model used by Shifman, Vainshtein, and Zakharov for the description of the experimental function R{sub c}(s) in the form of a sum of {delta}-functions and the plateau contradicts the Wilson operator expansion (O.E.) in the terms due to the gluon condensate. A QCD model with an infinite number of vector mesons does satisfy the requirements of the O.E. for masses and electronic width resonances close to the experimental values. The region of allowable values of the masses of c- and b-quarks and the gluon condensate compatible with the O.E. is obtained.
Date: November 1, 1993
Creator: Geshkenbein, B. & Morgunov, V.
Partner: UNT Libraries Government Documents Department

Measurements of the CP-violation parameter sin(2 beta) in B{superscipt 0} {right arrow} J/{psi}K{0 over S} decays

Description: In the 110 pb{sup -1} Run I data sample, using three complementary flavor-tagging algorithms CDF has made a new measurement of the CP-violating asymmetry sin(2{beta})=0.79{sup +0.41}{sub -0.44}, This corresponds to the limit sin(2{beta})>-0.08 at 95% confidence level. This result agrees well with predictions from indirect constraints based on fits of elements of the CKM matrix.
Date: May 11, 1999
Creator: Lewis, J. D.
Partner: UNT Libraries Government Documents Department

Summary of the parallel session on hadron dynamics

Description: The hadron dynamics sessions focussed on A-dependent effects in hard interactions and heavy quark production, as well as color transparency effects. Other topics covered included exclusive processes and spin effects.
Date: December 31, 1994
Creator: Corcoran, M.D. & Carroll, A.S.
Partner: UNT Libraries Government Documents Department

Anomalous charm production at large x{sub F}

Description: We show that the new QCD production mechanisms which were proposed by S.J. Brodsky, P. Hoyer, A.H. Mueller and the author can explain at least some of the anomalous behavior of open and/or closed charm production at large x{sub F}.
Date: October 1, 1995
Creator: Tang, W. K.
Partner: UNT Libraries Government Documents Department

Quarkonia production at CDF and D0

Description: In this paper we present results on J/{Psi}, {Psi}(2{ital S}), {chi}{sub c} and {Upsilon} production at {radical}s = 1.8 TeV. These results were obtained from data taken with the CDF and D0 detectors at Fermilab. We cover recently completed analyses of the 1992-1995 collider run. Prospects for the near future are also discussed.
Date: June 1, 1996
Creator: Papadimitriou, V. & Collaborations, CDF and D0
Partner: UNT Libraries Government Documents Department

Support of hadroproduction of bottom using the 800 GeV/c primary proton beam at the Fermilab tevatron. Final performance report, June 14, 1988--May 14, 1992

Description: The High Energy Physics (HEP) group at Prairie View A&M University is a collaborator with Fermi National Accelerator Laboratory (Fermilab), and the universities listed below. The purpose of this collaboration is to contribute to the understanding of heavy quark hadroproduction. Our efforts began in the early 1980`s at Fermilab with the study of the charmonium states, J/{psi} and {chi}, (DE-FG-86ER-40297) and presently with the continued studies of the charmonium system and direct photon production (Fermilab experiment E705) and new studies on bottom production (Fermilab experiment E771) in the High Intensity Laboratory (Proton-West Area) of Fermilab. The Prairie View group will, as a part of their task, be directly responsible for a major part of the PWC system upgrade by developing the electronics for the readouts of the PWC pad chambers. Six in all, these chambers, are a part of new multilevel triggering scheme and represents a departure from the triggering methodology of the previous trigger processors in earlier experiments. The Prairie View group is also involved with the Bottom Collider Detector (BCD) Collaboration which is proposing to study bottom production at the Fermilab Collider and at the Superconducting Super Collider (SSC).
Date: May 14, 1992
Creator: Judd, D.J.
Partner: UNT Libraries Government Documents Department

Observation of B{sup +} {yields} J/{psi}{pi}{sup +}

Description: We report on the observation of the Cabibbo-suppresed mode B{sup +} J/{psi}{pi}{sup +}, with J/{psi} {yields} {mu}{sup +}{mu}{sup {minus}}. Further, we calculate the relative branching ratio. BR(B{sup +} - J/{psi}{pi}{sup +})/BR(B{sup +} {yields} J/{psi}K{sup +}) and find a value of (4.9{sub {minus}1.7}{sup +}{plus_minus}1.1)%.
Date: July 1, 1995
Creator: Abe, F.
Partner: UNT Libraries Government Documents Department

Parton Cascade Description of Heavy Ion Collisions at CERN?

Description: There seems to be a general consensus now that a first glimpse of a QGP-like effect has become visible in the beautiful NA50 data on J/{psi} production and the anomalous suppression phenomenon. On the other hand, it is still widely believed that the dynamics of heavy-ion collisions at CERN SPS energy is predominantly governed by soft, non-perturbative physics. This is ironic: after all, it is unlikely that a QGP could be formed if the underlying dynamics were essentially soft, rather than that it requires intense quark-gluon production with sufficient cascade-like reinteractions which drive the matter to large density and equilibrium. Therefore, the author advocates in this contribution that for ultra-relativistic nucleus-nucleus collisions a description based on the pQCD interactions and cascade evolution of involved partons can and should be used, owing to the claim that short-range parton interactions play an important role at sufficiently high beam energies, including CERN energy {radical}s {approx_equal} 20 A GeV. Here mini-jet production which liberates of quarks and gluons cannot be considered as an isolated rare phenomenon, but can occur quite copiously and may lead to complex multiple cascade-type processes.
Date: February 1, 1998
Creator: Geiger, K.
Partner: UNT Libraries Government Documents Department

D0 papers on B-physics submitted to DPF '96: b-quark inclusive cross sections and b anti-b correlations using dimuons from the D0 experiment; Single muon production in the forward region at {radical}s=1.8 TEV; Rapidity dependence of the inclusive J{psi} production in the forward region {radical}s=1.8 TEV; A search for b {r_arrow} X{mu}{sup +}{mu}{sup {minus}} and B{sup 0} {r_arrow} {mu}{sup +}{mu}{sup {minus}} decays in p anti-p collisions at {radical}s=1.8 TEV

Description: Paper 1: Using dimuons collected with the D0 detector during the 1993--1995 Tevatron collider run, the authors have measured the b-quark cross section and b{anti b} correlations as given by the difference in azimuthal angle between the two muons. Both measurements agree with the NLO QCD predictions within experimental and theoretical errors. (Three other papers are included in this report.)
Date: November 1996
Creator: Vititoe, D. L.; Kozelov, Alexander; Jesik, Richard & Collaboration, D0
Partner: UNT Libraries Government Documents Department

Final performance report to the Department of Energy by Prairie View A & M University High Energy Physics

Description: The High Energy Physics (HEP) group at Prairie View A&M University is a collaboratory with Fermi National Accelerator Laboratory (Fermilab), and the universities listed below. The purpose of this collaboration is to contribute to the understanding of heavy quark hadroproduction. Our efforts began in the early 1980`s at Fermilab with the study of the charmonium states, J/{psi} and {chi}, (DE-FG-86ER-40297) and presently with the continued studies of the charmonium system and direct photon production (Fermilab experiment E705) and new studies on bottom production (Fermilab experiment E771) in the High Intensity Laboratory (Proton-West Area) of Fermilab. The Prairie View group will, as a part of their task, be directly responsible for a major part of the PWC system upgrade by developing the electronics for the readouts of the PWC pad chambers. Six in all, these chambers, are a part of new multilevel triggering scheme and represents a departure from the triggering methodology of the previous trigger processors in earlier experiments. The Prairie View group is also involved with the Bottom Collider Detector (BCD) Collaboration which is proposing to study bottom production at the Fermilab Collider and at the Superconducting Super Collider (SSC).
Date: May 14, 1992
Creator: Judd, D.J.
Partner: UNT Libraries Government Documents Department

J/{psi} and {psi}{prime} suppression by comovers in Pb+Pb collisions

Description: Measurements of {psi} and {psi}{prime} production at the CERN SPS are compared to predictions based on a hadronic model of charmonium suppression. Detailed information is presented to facilitate comparison to other analyses. Sensitivity of these conclusions to model parameters is discussed.
Date: November 1996
Creator: Gavin, S. & Vogt, R.
Partner: UNT Libraries Government Documents Department

Quarkonium production in proton antiproton collisions at the Tevatron

Description: Charmonium and bottomonium production is studied using {mu}{sup +}{mu}{sup -} data samples collected by the CDF and D{null} experiments during the 1992-96 {ital p{anti p}} collider run at the Fermilab Tevatron. The inclusive cross sections as a function of the transverse momentum of reconstructed quarkonium states are measured. The results are compared with theoretical predictions, which take into account different quarkonium production mechanisms.
Date: November 1, 1996
Creator: Tkaczyk, S.M. & Collaborations, CDF and D0
Partner: UNT Libraries Government Documents Department

Quarkonia production at CDF

Description: In the 1992-1995 runs CDF has collected large samples of {ital J/{psi}}, {psi}(2{ital S}) and {Gamma} identified through their muonic decay. In the charmonium system all production sources have been separately measured and compared with the theoretical predictions. A large excess of direct production has been observed for both {psi}(s{ital S}) and {ital J/{psi}}. the relative production rate for the {chi}{sub c}{sup 1} and {chi}{sub c}{sup 2} has also been measured. The unexpected results have lead to a profound revisitation of the theory of the production of {ital Q{anti Q}} bound states in high energy hadronic collisions.
Date: August 1, 1996
Creator: Sansoni, A.
Partner: UNT Libraries Government Documents Department

J/{psi} and {psi}{prime} suppression in high-energy heavy-ion collisions

Description: The anomalous suppression of J/{psi} production in Pb-Pb collisions at 158 GeV observed by the NA50 Collaboration can be explained as due to the occurrence of a new phase of strong J/{psi} absorption, which sets in when the local energy density exceeds about 3.4 GeV/fm{sup 3}. The peculiar behavior of the {psi}{sup `}/{psi} ratio in {ital p}-A and nucleus-nucleus collisions can be understood as due to approximately equal {psi}-N and {psi}{sup `}-N absorption cross sections, but greater absorption cross sections for {psi}{sup `} than J/{psi} with regard to absorption by soft particles and matter in the new phase.
Date: September 1, 1996
Creator: Wong, Cheuk-Yin
Partner: UNT Libraries Government Documents Department

Recent progress on perturbative QCD fragmentation functions

Description: The recent development of perturbative QCD (PQCD) fragmentation functions has strong impact on quarkonium production. I shall summarize B{sub c} meson production based on these PQCD fragmentation functions, as well as, the highlights of some recent activities on applying these PQCD fragmentation functions to explain anomalous J/{psi} and {psi}{prime} production at the Tevatron. Finally, I discuss a fragmentation model based on the PQCD fragmentation functions for heavy quarks fragmenting into heavy-light mesons.
Date: May 1, 1995
Creator: Cheung, K.
Partner: UNT Libraries Government Documents Department

Measurement of the average lifetime of B-hadrons produced in p{bar p} collisions at {radical}s = 1.8 TeV

Description: The average b-hadron lifetime has been measured using a high statistics sample of {ital B} {r_arrow} {ital J}/{psi}{Chi} decays recorded with the Collider Detector at Fermilab. We use a sample with an integrated luminosity of {approx} 90 {ital pb}{sup -1} recorded during the 1994-95 running period. The decay vertices of {approx} 62656 inclusive {ital J}/{psi} {r_arrow} {mu}{sup +}{mu}{sup -} candidates have been reconstructed using information from a silicon vertex-detector. The measured {ital B}lifetime, which is the average over all b-hadrons produced in {ital p}{ital {anti p}} collisions at {radical}s = 1.8 TeV weighted by their branching ratios into {ital J}/{psi}, is 1.524 {+-} 0.015 ({ital stat}){sup +0.035}{sub -0.026} ({ital sys}) ps. The precision of this measurement is significantly improved compared to the inclusive lifetime measurement published previously using {approx} 10 {ital pb}{sup -1}.
Date: August 1, 1996
Creator: Wenzel, H.
Partner: UNT Libraries Government Documents Department

Signatures of Absorption Mechanisms for J{psi} and {psi}` Production in High Energy Heavy-Ion Collisions

Description: J/psi and psi` produced in high-energy heavy-ion collisions are absorbed by their collisions with nucleons and produced soft particles, leading to two distinct absorption mechanisms. The signature of absorption by produced soft particles, as revealed by psi` production data, consists of a gap and a change of the slope in going from the pA line to the nucleus-nucleus line when we make a semi-log plot of the survival probability as a function of the path length. Using this signature, we find from the J/psi production data in pA, O-Cu, O-U, and S-U collisions that the degree of J/psi absorption by produced soft particles is small and cannot account for the J/psi data in Pb-Pb collisions. The anomalous suppression of J/psi production in Pb-Pb collisions can be explained as due to the occurrence of a new phase of strong J/psi absorption, which sets in when the local energy density exceeds about 3.4 GeV/fm3. To probe the chemical content of the new phase, we propose to study the abundance of open-charm mesons and charm hyperons which depends sensitively on the quark chemical potential.
Date: June 1, 1997
Creator: Wong, Cheuk-Yin
Partner: UNT Libraries Government Documents Department