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Example of an Antiproton-Nucleon Annihilation

Description: The existence of antiprotons has recently been demonstrated at the Berkeley Bevatron by a counter experiment. The antiprotons were found among the momentum-analyzed (1190 Mev/c) negative particles emitted by a copper target bombarded by 6.2-Bev protons. Concurrently with the counter experiment, stacks of nuclear emulsions were exposed in the beam adjusted to 1090 Mev/c negative particles in an experiment designed to observe the properties of antiprotons when coming to rest. This required a 132 g/cm2 copper absorber to slow down the antiprotons sufficiently to stop them in the emulsion stack. Only one antiproton was found in stacks in which seven were expected, assuming a geometric interaction cross section for antiprotons in copper. It has now been found that the cross section in copper is about twice geometric, which explains this low yield.
Date: February 27, 1956
Creator: Chamberlain, O.; Chupp, W.W.; Ekspong, A.G.; Goldhaber, G.; Goldhaber, S.; Lofgren, E.J. et al.
Partner: UNT Libraries Government Documents Department

Multifractal structures in multiparticle production in p -p interactions at radical s = 1800 GeV

Description: Fractal structure in multiparticle production of {bar p} {minus} p minimum-bias'' interactions at {radical}s = 1800 GeV has been studied using the Collider Detector at Fermilab. Preliminary results are shown and compared with very simple Monte Carlo models.
Date: August 1, 1990
Creator: Rimondi, F. (Bologna Univ. (Italy) Istituto Nazionale di Fisica Nucleare, Bologna (Italy))
Partner: UNT Libraries Government Documents Department

A quark-gluon plasma search in anti p --p at radical s = 1. 8 TeV

Description: The search by E-735 for QGP evidence in centrally produced particles in {bar p}p collisions has revealed several interesting results in the behavior with variation of dN{sub c}/d{eta} in the measured interval from 2--18. In {l angle}P{sub t}{r angle} we see a decrease in slope for all particles near dN{sub c}/d{eta} {approx equal} 9 corresponding to a Bjorken initial energy density of 2.2 GeV/{sub fm}{sup 3}. Above dN{sub c}/d{eta} = 10, the increase of {l angle}P{sub t}{r angle} is small except for {bar p}'s where the data suggest a 25% increase in the region 13--18. In the particle ratios, normalizing to {pi}'s, they (K, {bar p}, {Lambda}{sup 0}, {gamma}) are all independent of dN{sub c}/d{eta} within errors of {plus minus} 15% except for K{sup {plus minus}}/{pi}{sup {plus minus}} which increases by 30% in the interval 7 to 18. Based on the E-735 data analyzed to data, one can conclude that QGP is not manifest in {bar p}p collisions at 1.8 TeV. Nonetheless, there are the two effects mentioned above, which can be explored with much improved sensitivity using the high-statistics data of the '88--'89 run.
Date: October 8, 1990
Creator: Turkot, F.
Partner: UNT Libraries Government Documents Department

Neutron-antineutron oscillations in nuclei

Description: We briefly review the state of the art for extracting the period of neutron-antineutron oscillations from the lifetime of nuclei. The most recent data on nuclear stability provide a limit of 10{sup 8} s for the oscillation period. 13 refs.
Date: January 1, 1989
Creator: Dover, C.B.; Gal, A.; Richard, J.M. (Brookhaven National Lab., Upton, NY (USA); Hebrew Univ., Jerusalem (Israel). Racah Inst. of Physics & Grenoble-1 Univ., 38 (France). Inst. des Sciences Nucleaires)
Partner: UNT Libraries Government Documents Department

The Fermilab PBAR-P Collider: Present status and future plans

Description: The Tevatron Collider is performing beyond expectations for its first physics run. The peak luminosity is already 1.6 times the design goal of 10/sup 30/ cm/sup /minus/2/ s/sup /minus/1/. The anticipated integrated luminosity recorded by the major detector, CDF, is 3 inverse picobarns which should be sufficient to see the top quark if its mass is less than 110 GeV. The next two Collider runs will have improved performance with luminosity approaching 10/sup 31/ at two interaction regions. In the years between 1993 and 2000, the Collider energy will be increased by using the highest field superconducting magnets then available, where 8.8 T would give 2 TeV on 2 TeV pbar-p collisions with a luminosity above 10/sup 31/. To facilitate this possibility and to improve the general Collider capabilities, a new 150 GeV Main Injector is now being designed. 3 figs., 2 tabs.
Date: November 1, 1988
Creator: Johnson, R.
Partner: UNT Libraries Government Documents Department

The Missing Top: Prospects at the Tevatron

Description: A new run has begun at the Tevatron Collider, and two detectors, CDF and D0, have started taking data. After a short review of the situation of the top search in both the single and dilepton channel, we present the expectations for the near and far future. There have already been accelerator and detector upgrades, and more are to come. Important improvements are also expected from new analysis tools.
Date: December 1, 1992
Creator: Cobal, M.
Partner: UNT Libraries Government Documents Department

Nucleon-antinucleon annihilation in chiral soliton model

Description: We investigate annihilation process of nucleons in the chiral soliton model by the path integral method. A soliton-antisoliton pair is shown to decay into mesons at range of about 1fm, defined by the S{bar S} potential. Contribution of the annihilation channel to the elastic scattering is discussed.
Date: September 7, 1991
Creator: Musakhanov, M. M. & Musatov, I. V.
Partner: UNT Libraries Government Documents Department

Proton-proton and proton-antiproton elastic scattering at high energies: Theory, phenomenology, and experiment

Description: This is a brief review of the progress in the understanding, during the past twenty years, of hadronic elastic scattering near the forward direction at high energies. On the basis of quantum gauge field theories, the Pomeron is found to be a branch cut above 1. Using the physical picture that this result implies, phenomenology for proton-proton and antiproton-proton elastic scattering is constructed. Two noteworthy features are that, at high energies, both the total cross section and the ratio of the integrated elastic cross section to the total cross section to the total cross section are increasing functions of the center-of-mass energy. Detailed predictions are given for the elastic differential cross sections, Coulomb interference and the ratios of the real to imaginary parts of the forward amplitudes. These predictions have been extensively and accurately confirmed by experiments, and have also been given both for future experiments on existing accelerators and for experiments on future accelerators. 14 refs., 2 figs.
Date: January 1, 1990
Creator: Wu, Tai Tsun.
Partner: UNT Libraries Government Documents Department

An Experimental High Energy Physics Program: Task D

Description: This report discusses: The CDF for {bar p}-p Collisions at FNAL; The L3 Detector for e{sup +}e{sup {minus}} Collisions at CERN; The SCD Detector for pp Collisions at the SSCL (calorimeters); The SDC Detector for pp Collisions at the SSCL (muon detector); The CO experiment for {bar p}-p Collisions at FNAL; and Accelerator Physics at Fermilab.
Date: January 1, 1992
Creator: Barnes, V.E.; Carmony, D.D.; Garfinkel, A.F. & Gutay, L.J.
Partner: UNT Libraries Government Documents Department

Review of total cross sections and forward scattering parameters at ultra-high energies

Description: We review the field of the elastic scattering of pp and {bar p}p at the ultra-high energies. The recent total cross section, {sigma}{sub tot}, and {rho}-value results from the Fermilab Tevatron Collider experiments presented at the 4th Blois' Workshop on Elastic and Diffractive Scattering (Elba, Italy, in May, 1991), allow us a comprehensive overview of the field. 24 refs., 10 figs., 3 tabs.
Date: October 1, 1991
Creator: Block, M.M. (Northwestern Univ., Evanston, IL (United States). Dept. of Physics and Astronomy) & White, A.R. (Argonne National Lab., IL (United States). High Energy Physics Div.)
Partner: UNT Libraries Government Documents Department

Nucleon-antinucleon annihilation in chiral soliton model

Description: We investigate annihilation process of nucleons in the chiral soliton model by the path integral method. A soliton-antisoliton pair is shown to decay into mesons at range of about 1fm, defined by the S{bar S} potential. Contribution of the annihilation channel to the elastic scattering is discussed.
Date: September 7, 1991
Creator: Musakhanov, M.M. (Washington Univ., Seattle, WA (United States). Inst. for Nuclear Theory Tashkentskij Gosudarstvennyj Univ., Tashkent (USSR). Dept. of Theoretical Physics) & Musatov, I.V. (Tashkentskij Gosudarstvennyj Univ., Tashkent (USSR). Research Inst. of Applied Physics)
Partner: UNT Libraries Government Documents Department

Implications for supersymmetry of the CERN monojets

Description: Results of a comprehensive study of supersymmetric processes which could give monojet events similar to those observed at the CERN Sp anti pS are presented. If supersymmetry is to be the explanation of the monojets, strict bounds are obtained on possible supersymmetric masses. 15 references.
Date: January 1, 1985
Creator: Haber, H.E.
Partner: UNT Libraries Government Documents Department

Search for narrow structure in proton-antiproton annihilation cross sections from 1900 to 1960 MeV

Description: The anti pp annihilation cross section has been measured with good resolution (approx.2 MeV rms) in the mass range 1900-1960 MeV. No narrow structures are seen, the 90% confidence level upper limit being 8-12 mb-MeV for the integrated area of a resonance in this mass range. However, we do not rule out a very narrow bump-dip structure seen in an earlier experiment in the 1935-1941 MeV mass interval. The data also do not support the existence of a broad structure previously reported at 1937 MeV.
Date: January 1, 1985
Creator: Lowenstein, D.I.; Pealsee, D.C.; Miller, R.J.; Lewis, R.A.; Oh, B.Y.; Smith, G.A. et al.
Partner: UNT Libraries Government Documents Department

Status of perturbative QCD

Description: In this talk is discussed, within the framework of perturbative QCD, four topics which have received theoretical attention in the last year. They are: (1) jets at the CERN Sp anti p S collider, (2) power corrections to leptoproduction, (3) hard scattering off nuclear targets, and (4) the photon structure function. 28 references.
Date: August 1, 1983
Creator: Ellis, R.K.
Partner: UNT Libraries Government Documents Department

Search for narrow structures in the anti pp annihilation cross section from 1925 to 1955 MeV

Description: The anti pp annihilation cross section has been measured over the CM energy range 1925 to 1955 MeV with an RMS resolution of +-2.5 MeV on the average. This search yields no evidence for narrow enhancements in the S(1936) region. Using an A + B/p dependent background, a two standard deviation upper limit of 9 mb-MeV is set for the integrated area of any resonance with mass between 1936 and 1942 and with width less than or equal to 4 MeV.
Date: January 1, 1980
Creator: Lowenstein, D I; Peaslee, D C & Bromberg, C
Partner: UNT Libraries Government Documents Department

Recent experimental results on the beam-beam effects in storage rings and an attempt of their interpretation

Description: The latest available experimental results on the luminosity, the space charge parameters, and the beam blowup as functions of particle energy and beam current are reviewed. The comparison with the phenomenological diffusion theory is done and useful scaling laws are derived. Some implications for anti p p storage rings are discussed.
Date: June 1, 1980
Creator: Kheifets, S.
Partner: UNT Libraries Government Documents Department

Calculations of anti pp. -->. anti yy near threshold

Description: The reactions anti pp ..-->.. anti yy will soon be studied near threshold at LEAR. Comparison of theoretical calculations with the measured differential cross sections, polarizations and spin correlations may help to determine the role of various meson exchange terms and the extent to which quark degrees of freedom are important. Calculations along these lines are in progress and are described briefly.
Date: January 1, 1982
Creator: Eisenstein, R. A.
Partner: UNT Libraries Government Documents Department

Fragmentation properties of jets produced in proton-antiproton collisions at radical S = 1. 8 TeV

Description: Jet fragmentation properties have been studied in collisions of protons and antiprotons at a center-of-mass energy of 1.8 TeV, using the Collider Detector at Fermilab (CDF). The fractional momentum distribution of charged particles within jets is presented and compared with Monte-Carlo predictions. With increasing di-jet invariant mass from 60 to 200 GeV/c{sup 2} the fragmentation is observed to soften as predicted by scale breaking effects in Quantum Chromodynamics (QCD). The charged multiplicity in the jet core is observed to rise with di-jet invariant mass. 57 refs.
Date: November 1, 1989
Creator: Hubbard, B. (California Univ., Berkeley, CA (USA). Dept. of Physics):(Lawrence Berkeley Lab., CA (USA))
Partner: UNT Libraries Government Documents Department

Intermediate vector bosons in the muon channel

Description: Description of the W{sup {plus minus}} and Z{sup 0} mass measurement in the muon decay channel, using 4.4 pb{sup {minus}1} of proton-antiproton collision data from the Fermilab Tevatron and CDF. A preliminary result of M{sub w} = 79.9 {plus minus} 0.4 {plus minus} 0.6 GeV/c{sup 2} is presented, and the published values of M{sub z} = 90.9 {plus minus} 0.3 {plus minus} 0.2 GeV/c{sup 2} and {Gamma}{sub z} = 3.8 {plus minus} 1.1 {plus minus} 1.0 GeV/c{sup 2} are described. 8 refs., 5 figs., 6 tabs.
Date: December 1, 1989
Creator: Smith, D.A.
Partner: UNT Libraries Government Documents Department