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D0 findings on the top quark

Description: Recent results on top quark physics with the D0 experiment in pp collisions at {radical}s = 1.8 TeV are reported. The direct measurement of the top quark mass uses single lepton and dilepton events, giving the result m{sub top} = 172.1 {+-} 7.1 GeV/c{sup 2} . The measurement of the t{anti t} production cross section includes analyses from 9 top decay channels: dilepton, electron and neutrino, single leptons with and without b tagging, and all-jets (t{anti t} {r_arrow} b jets). The authors measured the t{anti t} production cross section to be 5.9 {+-} 1.7 pb at m{sub top} = 172.1 GeV/c{sup 2}. Preliminary results on a search for charged Higgs production in top events are presented.
Date: June 1, 1998
Creator: Klima, B.
Partner: UNT Libraries Government Documents Department

Phenomenological implications of low energy supersymmetry breaking

Description: The experimental signatures for low energy supersymmetry breaking are presented. The lightest standard model superpartner is unstable and decays to its partner plus a Goldstino, G. For a supersymmetry breaking scale below a few 1,000 TeV this decay can take place within a detector, leading to very distinctive signatures. If a neutralino is the lightest standard model superpartner it decays by {chi}{sub 1}{sup 0} {r_arrow} {gamma} + G, and if kinematically accessible by {chi}{sub 1}{sup 0} {r_arrow} (Z{sup 0}, h{sup 0}, H{sup 0}, A{sup 0}) + G. These decays can give rise to displaced vertices. Alternately, if a slepton is the lightest standard model superpartner it decays by {tilde l} {r_arrow} l + G. This can be seen as a greater than minimum ionizing charged particle track, possibly with a kink to a minimum ionizing track.
Date: July 1, 1996
Creator: Dimopoulos, S.; Dine, M.; Raby, S.; Thomas, S. & Wells, J.D.
Partner: UNT Libraries Government Documents Department

Searching for new physics with charm

Description: The author considers the prospect of using the charm system as a laboratory for probing new physics. The theoretical expectations for rare charm meson decays, D{sup 0} - {bar D}{sup 0}, and charm quark asymmetries in Z decays are examined in the Standard Model. The effects of new physics from several classes of nonstandard dynamical models are summarized for these phenomena.
Date: June 1995
Creator: Hewett, J. L.
Partner: UNT Libraries Government Documents Department

Explicit quark-hadron duality in 1+1 dimensions

Description: Explicit quark-hadron duality in the limit of heavy quark mass is studied using the 't Hooft model, where both partonic and hadronic amplitudes may be computed exactly. Results for weak decays of heavy mesons are presented for both standard spectator decays, where the duality limit is convincingly approached, and annihilation decays of the valence quark-antiquark pair, where the approach to asymptotic duality is much less precise.
Date: June 1, 1998
Creator: Lebed, Richard F.
Partner: UNT Libraries Government Documents Department

Experimental study of sin 2 {beta} and sin 2 {alpha}

Description: Detailed measurements of CP violation in B meson decay are on the horizon. Here the author reviews the status of current measurements of sin 2{beta} made at LEP and CDF. These yield an average of sin 2{beta} = 0.82 {+-} 0.39, giving 97% confidence that {beta} is greater than 0, evidence that CP violation occurs in B decay. He reviews predictions for the precision one can expect on sin 2{beta} and sin 2{alpha} in the next few years.
Date: March 7, 2000
Creator: Truschuk, W.
Partner: UNT Libraries Government Documents Department

Probing new physics in B Penguins

Description: Constraints placed on physics beyond the Standard Model from the recent CLEO observation of the inclusive decay B {yields} X{sub s}{gamma} are summarized. Further searches for new physics using the process B {yields} X{sub s}l{sup +}l{sup {minus}} are discussed.
Date: February 1, 1995
Creator: Hewett, J.L.
Partner: UNT Libraries Government Documents Department

Hyperon particle physics at JHF

Description: This paper discusses the possibility of a program in hyperon decay physics at the Japan Hadron Facility. The study of hyperon decays has a history of over 40 years of experimental results. However, many of the earliest results are still the best available and there are many gaps in the data. The static properties of hyperons (masses, magnetic moments) are in relatively good shape. Much work remains to be done on the decays of hyperons and hyperon resonances. There are current experiments at the major accelerator facilities that address various hyperon decays, but no comprehensive program. This presents an excellent opportunity for such a program to be considered at JHF. The high-intensity beams of {pi}, K, and p beams will allow experiments to be designed that optimize the properties of the hyperons being studied. It is possible to envision experiments with samples of 10{sup 9} hyperon decays in 10{sup 7} sec runs.
Date: December 1, 1998
Creator: Mischke, R.E.
Partner: UNT Libraries Government Documents Department

CDF results on B decays

Description: The authors present recent CDF results on B lifetimes, B meson mass measurements, ratios of branching ratios, and rare decays. In addition, they present the first measurement of time-dependent B{sub d} mixing at CDF. Several results have been updated and a few new ones included since the workshop.
Date: May 1995
Creator: Skarha, J. E.
Partner: UNT Libraries Government Documents Department

Supersymmetry and supergravity: Phenomenology and grand unification

Description: A survey is given of supersymmetry and supergravity and their phenomenology. Some of the topics discussed are the basic ideas of global supersymmetry, the minimal supersymmetric Standard Model (MSSM) and its phenomenology, the basic ideas of local supersymmetry (supergravity), grand unification, supersymmetry breaking in supergravity grand unified models, radiative breaking of SU(2) {times} U(1), proton decay, cosmological constraints, and predictions of supergravity grand unified models. While the number of detailed derivations are necessarily limited, a sufficient number of results are given so that a reader can get a working knowledge of this field.
Date: December 31, 1993
Creator: Arnowitt, R. & Nath, P.
Partner: UNT Libraries Government Documents Department

Search for the decay B{sup 0} {yields} {mu}{sup +}{mu}{sup {minus}}

Description: The authors present a search for the decays B{sub d}{sup 0} {yields} {mu}{sup +}{mu}{sup {minus}} and B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup {minus}} using 17.8 pb{sup {minus}1} of data collected with the Collider Detector at Fermilab (CDF) during 1992--1993 data taking period. They find no B{sub d}{sup 0} candidates in a mass window of [5.205, 5.355] GeV/c{sup 2} and 1 B{sub s}{sup 0} candidate in a mass window of [5.300, 5.450] GeV/c{sup 2}. Normalizing to the measured cross-section {sigma} (B{sup +}) = 2.39 {+-} 0.54 {micro}b for p{sub t}(B) > 6 GeV/c and {vert_bar}y(B){vert_bar} < 1 and assuming {sigma}(B{sup +}) = {sigma}(B{sub d}{sup 0}) = 3{sigma}(B{sub s}{sup 0}), they find Br(B{sub d}{sup 0} {yields} {mu}{sup +}{mu}{sup {minus}}) < 1.6 {times} 10{sup {minus}6} and Br(B{sub s}{sup 0} {yields} {mu}{sup +}{mu}{sup {minus}}) < 8.4 {times} 10{sup {minus}6} at 90% confidence level. These limits are significant improvements of previous measurements.
Date: July 1, 1995
Creator: Abe, F.
Partner: UNT Libraries Government Documents Department

CP violation in K decays and rare decays

Description: The present status of CP violation in decays of neutral kaons is reviewed. In addition selected rare decays of both K and B mesons are discussed. The emphasis is in particular on observables that can be reliably calculated and thus offer the possibility of clean tests of standard model flavor physics. 105 refs.
Date: December 1, 1996
Creator: Buchalla, G.
Partner: UNT Libraries Government Documents Department

Jet angular decorrelation and color coherence in p{bar p} collisions at {radical}s = 1.8 TeV

Description: We present three QCD studies based on data collected by the d{O} detector during the 1992-1993 and 1994-1995 runs at the Fermilab Tevatron collider at center of mass energy {radical}s = 1.8 TeV. The first study is an analysis of jet-jet azimuthal decorrelation as a function of jet rapidity separation. The second and third studies are probes of color coherence effects in hadronic collisions - one using multi-jet events and the other using W+jet events.
Date: August 1, 1996
Creator: Jaques, J.
Partner: UNT Libraries Government Documents Department

Tau physics results from SLD

Description: Results on {tau} physics at SLD are presented. They are based on 4,316 {tau}-pair events selected from a 150 k Z{sup 0} data sample collected at the SLC. These results include measurements of the {tau} lifetime ({tau}{sub r} = 288.1 {+-} 6.1 {+-} 3.3 fs), the {tau} Michel parameters ({rho} = 0.71 {+-} 0.09 {+-} 0.04, {zeta} = 1.03 {+-} 0.36 {+-} 0.05, and {zeta}{delta} = 0.84 {+-} 0.27 {+-} 0.05), and the {tau} neutrino helicity (h{sub {nu}} = {minus}0.81 {+-} 0.18 {+-} 0.03).
Date: August 10, 1996
Creator: Daoudi, M. & Collaboration, SLD
Partner: UNT Libraries Government Documents Department

Rare decays experimental summary and prospects

Description: I review the status and future prospects of searches for forbidden and highly kaon suppressed decays. This workshop comes as we are poised at the threshold of a new generation of rare K decay experiments. There are new experiments running or about to run at KEK, BNL, FNAL, and CERN. In another year or so these will be joined by the KLOE experiment at DA{Phi}NE. The good news is that it`s a very exciting time. The bad news, at least for a reviewer, is that there aren`t too many new results. Thus I`ll be giving a little more attention than usual to what the experimenters expect to do. My discussion of rare K decays covers processes that are forbidden in the Standard Model, those that highly suppressed and to a smaller extent, those that are merely discouraged.
Date: December 31, 1996
Creator: Littenberg, L.
Partner: UNT Libraries Government Documents Department

Top quark measurements at the Tevatron

Description: The authors present top physics results from the CDF and D0 collaborations. The data were collected at the Fermilab Tevatron over the years 1992--1995 and correspond to approximately 110 pb{sup {minus}1} of p{anti p} collisions. Both experiments present determination of the t{anti t} production cross section using a variety of top decay channels, and refined measurements of the top mass.
Date: January 1, 1997
Creator: Kestenbaum, D. S.
Partner: UNT Libraries Government Documents Department

Search for leptoquarks at CDF

Description: We present the result of direct leptoquark searches based on 110 pb{sup -1} of integrated luminosity collected by the Collider Detector at Fermilab during the 1992-93 and 1994-95 Tevatron runs at {radical}s = 1.8 TeV. We present upper limits on the production cross sections as a function of the leptoquark mass. Using the NLO calculation of the leptoquark-pair production cross sections we extract lower-mass limits for 1{sup st}, 2{sup nd}, and 3{sup d} generation leptoquarks. We also present the result of an indirect search for Pati-Salam leptoquarks via exclusive e{mu} decay modes of B{sup 0}{sub s} and B{sup 0}{sub d}
Date: July 1, 1997
Creator: Kambara, H. S.
Partner: UNT Libraries Government Documents Department

University of Virginia High Energy Physics Group. Final performance report, June 1, 1989--January 31, 1994

Description: The US Department of Energy Contracts for 1989 covered the initial year of the University of Virginia High Energy Physics Group. The first proposal was submitted in the fall of 1988 and the first allocation of funding was received in June 1989. This first contract which covered the time period June 1, 1989--January 31, 1990 was in the amount of $186,000 and covered UVa HEP group operations and equipment during that period. At that point, a regular contract year was established and two subsequent contracts were issued for February 1, 1990--January 31, 1991 and February 1, 1991--January 31, 992 with awards of $280,000 and $580,000, respectively. The funding between June, 1989 and January, 1992 covered the activities of both the UVa Theory Group (Task A) and the UVa HEP Experimental Group (Task B). Expenditures of all above funds was completed by January 31, 1994. In this time period, certain initial things were accomplished using the operating funds provided by DOE and the seed funds ($2.2 million over the period). There were three main areas of activities, the building of the University of Virginia HEP infrastructure (construction of lab space, computer facilities, electronic shop, machine shop and office space), the hiring of personnel (faculty, post docs, and students) and the physics activities of the group. Much of the physics program of the experimental group revolved around the study of production and decay of heavy flavor. A list of technical papers generated by their work is provided.
Date: December 31, 1994
Partner: UNT Libraries Government Documents Department

Rare and forbidden kaon decays at the AGS

Description: An overview of the Rare Kaon Decay program at the AGS is presented, with particular emphasis on the three major experiments currently running and analyzing data. A brief overview of earlier kaon decay experiments and of the AGs performance improvements is also provided. This review concludes with a discussion of proposed and developing experiments planned to run in the year 2000 and beyond (AGS-2000).
Date: December 9, 1997
Creator: Kettell, S.
Partner: UNT Libraries Government Documents Department

Discovery mass reach for topgluons decaying to b{bar b} at the Tevatron

Description: In topcolor assisted technicolor, topgluons are massive gluons which couple mainly to top and bottom quarks. We estimate the mass reach for topgluons decaying to {ital b{anti b}} at the Tevatron as a function of integrated luminosity. The mass reach for topgluons decreases with increasing topgluon width, and is 0.77-0.95 TeV for Run II (2 fb{sup -1}) and 1.0 - 1.2 TeV for TeV33 (30 fb{sup -1}).
Date: September 1, 1996
Creator: Harris, R.M.
Partner: UNT Libraries Government Documents Department

Improved upper limits on B(K{sub L}{sup 0} {r_arrow} {mu}e) and B(K{sub L}{sup 0} {r_arrow} ee) and a new value for B(K{sub L}{sup 0} {r_arrow} {mu}{mu})

Description: The author gives recent results from E791 at BNL with improved upper limits on the branching fractions B(K{sub L}{sup 0} {r_arrow} {mu}e) and B(K{sub L}{sup 0} {r_arrow} ee) of 8.5 {times} 10{sup {minus}11} and 11.6 {times} 10{sup {minus}11} at 90% C.L. He also gives a preliminary result of a new measurement B(K{sub L}{sup 0} {r_arrow} {mu}{mu}) = 7.6 {+-} 0.5(stat) {+-} 0.4(syst) {times} 10{sup {minus}9}.
Date: September 1, 1998
Creator: Molzon, W.R.
Partner: UNT Libraries Government Documents Department

Spin correlation in t{anti t} production from p{anti p} collisions at {radical}s = 1.8 TeV

Description: The Standard Model predicts that the lifetime of the top quark is shorter than the typical time scale at which hadronization process occurs, and the spin information at its production is preserved. Spin correlation of the t{anti t} system from p{anti p} collisions at the Tevatron is analyzed using 6 events in the dilepton channels collected using the D0 detector. Spin correlation factor of {kappa} &gt; {minus} 0.25 at 68% CL is obtained from the data.
Date: June 15, 2000
Creator: Choi, Suyong
Partner: UNT Libraries Government Documents Department

Top polarization at a {mu}{sup +} {mu}{sup {minus}} collider

Description: The top quark pairs produced at a polarized muon collider are in a (nearly) pure spin configuration. This result holds for all center-of-mass energies, and is insensitive to the next-to-leading order QCD radiative corrections. The decay products of a polarized top quark show strong angular correlations. The authors describe an interesting interference effect between the left-handed and longitudinally polarized W bosons in top quark decay. This effect is easily observable in the angular distribution of the charged lepton with respect to the beam axis.
Date: January 27, 2000
Creator: Parke, S. & Mahlon, G.
Partner: UNT Libraries Government Documents Department

CP violation in top physics at the NLC

Description: Top quark is extremely sensitive to non-standard CP violating phases. General strategies for exposing different types of phases at the NLC are outlined. SUSY phase(s) cause PRA in t {r_arrow} Wb. The transverse polarization of the {tau} in the reaction t {r_arrow} b{tau}{nu} is extremely sensitive to a phase from the charged Higgs sector. Phase(s) from the neutral Higgs sector cause appreciable dipole moment effects and lead to sizable asymmetries in e{sup +}e{sup {minus}} {r_arrow} t{anti t}H{sup 0} and e{sup +}e{sup {minus}} {r_arrow} t{anti t}{nu}{sub e}anti({nu}{sub e}).
Date: September 1, 1996
Creator: Atwood, D. & Soni, A.
Partner: UNT Libraries Government Documents Department