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Discrete symmetries: A broken look at QCD

Description: The alphabet soup of discrete symmetries is briefly surveyed with a view towards those which can be tested at LISS and two particularly interesting cases are called out. A LISS experiment may be able to distinguish CP violation that is not due to the QCD {theta} term. The elements of a model of parity violation in proton-nucleon scattering, which is consistent with lower energy LAMPF and ANL results, are reviewed in the light of new information on diquarks and the proton spin fraction carried by quarks. The prediction that the parity violating total cross section asymmetry should be large at LISS energies is confirmed. The results of such an experiment can be used both to obtain new information about the diquark substructure of the nucleon and to provide bounds on new right-chiral weak interactions.
Date: August 1, 1996
Creator: Goldman, T.
Partner: UNT Libraries Government Documents Department

Experimental studies of the quark-gluon structure of nucleons and nuclei and of pion- and proton-nucleus interactions. Progress report, April 1, 1994--March 31, 1997

Description: This report summarizes the work on experimental research in intermediate energy nuclear physics carried out by New Mexico State University from April 1, 1994, through March 31, 1996 under a grant from the US Department of Energy. During this period we began phasing out our programs of study of pion-nucleus and pion-nucleon interaction and of nucleon-nucleus charge-exchange reactions, which have been our major focus of the past two or three years. At the same time we continued moving in a new direction of research on studies of the internal structure of nucleons and nuclei in terms of quarks and gluons. The pion and nucleon work has been aimed at improving our understanding of the nature of pion and proton interactions in the nuclear medium and of various aspects of nuclear structure. The studies of the quark-gluon structure of nucleons are aimed at clarifying such problems as the nature of the quark sea and the relation of the nucleon spin to the spins of the quarks within the nucleon, questions which are of a very fundamental nature.
Date: October 1, 1996
Partner: UNT Libraries Government Documents Department


Description: The role of proton-nucleus (p-A) collisions in the study of strong interactions has a long history. It has been an important testing ground for QCD. At RHIC p-A studies have been recognized since the beginning as important elements of the program. These include so-called baseline measurements in cold nuclear matter, essential (along with p-p studies) to a systematic study of QCD at high temperatures and densities in the search for the quark gluon plasma. Also accessible is a study of QCD in the small x (parton saturation) regime, complementary to physics accessible in high-energy e-p and e-A collisions. The role of p-A physics at RHIC was reviewed and brought into sharp focus at a workshop conducted in October 2000 at BNL; the agenda is shown in Appendix 1. This document summarizes the case for p-A at RHIC during the period covered by the next Nuclear Physics Long Range Plan. In subsequent sections we cover the Physics Issues, Experiment Run Plans and Schedule, Detector Upgrade Issues, and Machine Issues & Upgrades.
Date: March 1, 2001
Creator: ARONSON,S.H. & PENG,J.C.
Partner: UNT Libraries Government Documents Department

Nuclear transparency from quasielastic A(e,e'p) reactions up to Q{sup 2}=8.1 (GeV/c){sup 2}

Description: The quasielastic (e,e'p) reaction was studied on targets of deuterium, carbon, and iron up to a value of momentum transfer Q{sup 2} of 8.1 (GeV/c){sup 2}. A nuclear transparency was determined by comparing the data to calculations in the Plane-Wave Impulse Approximation. The dependence of the nuclear transparency on Q{sup 2} and the mass number A was investigated in a search for the onset of the Color Transparency within our range of Q{sup 2}. A fit to the world's nuclear transparency data reflects the energy dependence of the free proton-nucleon cross section.
Date: August 1, 2001
Creator: Garrow, K. & al., et.
Partner: UNT Libraries Government Documents Department

Massive lepton pairs as a prompt photon surrogate

Description: The authors discuss the transverse momentum distribution for the production of massive lepton-pairs in hadron reactions at fixed target and collider energies within the context of next-to-leading order perturbative quantum chromodynamics. For values of the transverse momentum Q{sub T} greater than the pair mass Q, Q{sub T} > Q, they show that the differential cross section is dominated by subprocesses initiated by incident gluons. Massive lepton-pair differential cross sections are an advantageous source of constraints on the gluon density, free from the experimental and theoretical complications of photon isolation that beset studies of prompt photon production. They compare calculations with data and provide predictions for the differential cross section as a function of Q{sub T} in proton-antiproton reactions at center-of-mass energies of 1.8 TeV, and in proton-nucleon reactions at fixed target and LHC energies.
Date: March 1, 1998
Creator: Berger, Edmond L.; Gordon, Lionel E. & Klasen, Michael
Partner: UNT Libraries Government Documents Department

Probing nuclei with high-energy hadronic reactions

Description: I review the subject of hadron-nucleus collisions at energies where peturbative theory is applicable. Reactions studied experimentally at the Fermilab Tevatron and CERN`s Super Proton Synchrotron include the Drell-Yan Process, direct photon production, quarkonium production, and open charm production. I conclude with an observation about a new era of proton-nucleus and nucleus-nucleus experiments which will be carried out at the hadron colliders, RHIC and LHC.
Date: December 1, 1995
Creator: Moss, J.M.
Partner: UNT Libraries Government Documents Department

J/{sub psi} production: Tevatron and fixed-target collisions

Description: In this talk the author shows the results of a fit of the NRQCD matrix elements to the CDF data for direct J/{psi} production, by including the radiative corrections to the g g {r_arrow} {sup 3} S {sub 1}{sup [1]} channel and the effect of the k{sub T}-smearing. Furthermore he performs the NLO NRQCD analysis of J/{psi} production in fixed-target proton-nucleon collisions and he fits the colour-octet matrix elements to the available experimental data. The results are compared to the Tevatron ones.
Date: June 1, 2000
Creator: Petrelli, A.
Partner: UNT Libraries Government Documents Department

Double semi-leptonic charm decay in helios-I 450 GeV/c p-Be data. Appendix 1

Description: Data taken in 1989 by HELIOS-I (NA34) at the CERN SPS (450 GeV/c proton beam on Be target) have been examined for e{sup {plus_minus}} {mu}{sup {minus_plus}} or {mu}{sup {plus_minus}} {mu}{sup {minus_plus}} pairs with associated missing energy. Such pairs arise from semi-leptonic decay of both members of a c{bar c} pair. The e{mu} and {mu}{mu} samples are consistent with expectations from charm decay, allowing a quantitative limit to be placed on other physics.
Date: December 31, 1992
Creator: Pierre, A. & Pomianowski, P. A.
Partner: UNT Libraries Government Documents Department

Nuclear rescattering effects in pA {yields} dihadrons

Description: Based upon recent dijet angular correlation measurements, we point out that the parameter {alpha} in the A{alpha} cross section parameterization can be substantially affected by the angular acceptance of the two-arm spectrometer apparatus used to measure dihadron production from nuclear targets. Correction for this acceptance effect could well bring the results of some published 400 GeV dihadron experiments into better agreement with each other.
Date: December 31, 1992
Creator: Fields, T. & Corcoran, M. D.
Partner: UNT Libraries Government Documents Department

E789 and P865: High-rate fixed-target studies of charm and beauty

Description: Experiment 789 at Fermilab used the high-rate E605/E772 spectrometer to study low-multiplicity charm and beauty decays. Preliminary results on charm and beauty production are presented based on analysis of {approx} 100% of the charm data and {approx} 50% of the beauty data. A new experiment is proposed to improve charm and beauty sensitivity by several orders of magnitude.
Date: June 1, 1993
Creator: Kaplan, D. M. & Collaborations, E789 and P865
Partner: UNT Libraries Government Documents Department

Study of nuclear fragment emission in proton heavy nucleus collision from 10 to 500 GeV/c

Description: We propose to measure the double differential cross section of nuclear fragments (2 less than or equal to Z less than or equal to 16), for a given incident momentum, produced by proton heavy nucleus (20 less than or equal to Z less than or equal to 80) collisions in the 10 to 500 GeV/c momentum range. Recent experimental results and theoretical speculations suggest collective nuclear motion is initiated by the passage of a fast proton through a heavy nucleus. The novel feature of this experiment is the determination of the energy dependence of the excitation mechanism. Because nuclear fragments are best studied from thin targets, one needs a very high beam flux to obtain sufficient event rates. These considerations make the Internal Target Area with a heavy gas jet target the ideal place to initiate our experimental program. The detection system will consist of four conventional $delta$E- E semiconductor telescopes. (auth)
Date: September 16, 1975
Partner: UNT Libraries Government Documents Department

Empirical proton-neutron interaction strengths

Description: An empirical technique to extract proton-neutron interaction energies for specific protons and neutrons in a wide variety of nuclei is described. The results shed light on the roles of the monopole and quadrupole components of the p-n interaction, their orbit dependence, the microscopic basis of the N/sub p/N/sub n/ scheme, and the saturation of collectively observed in deformed nuclei. 3 refs., 4 figs.
Date: January 1, 1989
Creator: Casten, R.F.; Zhang, J.Y. & Brenner, D.S.
Partner: UNT Libraries Government Documents Department

Neutron-proton bremsstrahlung experiments

Description: It is well known that charged particles emit bremsstrahlung radiation when they are accelerated. Classical electron bremsstrahlung occurs when a photon is emitted by an electron accelerated in the field of a nucleus. The bremsstrahlung process also occurs in the scattering of nucleons, for which it is the lowest energy inelastic process that can occur. Like electron bremsstrahlung, nucleon-nucleon bremsstrahlung also requires the exchange of a virtual particle to conserve energy and momentum. In electron bremsstrahlung a virtual photon is exchanged but with two nucleons a meson can be exchanged. Unlike electron bremsstrahlung, in nucleon-nucleon bremsstrahlung the photon can originate from the exchanged meson. This exchange contribution has been shown in calculations to be a significant fraction of bremsstrahlung events. Thus bremsstrahlung serves as a probe of exchange currents in the nucleon-nucleon interaction. Because of a lack of a free neutron target or an intense neutron beam, few measurements of neutron-proton bremsstrahlung exist, each having poor statistical accuracy and poor energy resolution. The white neutron source at the Weapons Neutron Research (WNR) target area at the Los Alamos Meson Physics Facility (LAMPF) produces neutrons with energies from below 50 to above 400 MeV. Using time-of-flight techniques and a liquid hydrogen target, we are measuring the outgoing photons of energies up to 250 MeV at gamma ray angles of around 90[degree] relative to the incident beam. Protons scattered at very forward angles are also detected in coincidence with the gamma rays.
Date: January 1, 1992
Creator: Koster, J.E.; Nelson, R.O.; Schillaci, M.E.; Wender, S.A. (Los Alamos National Lab., NM (United States)); Mayo, D.; Brady, F.P. et al.
Partner: UNT Libraries Government Documents Department

Nuclear structure studies at intermediate energies. Summary progress report, 1987--1990

Description: This report discusses the following topics: Search for dibaryon resonances; analysis of {sup 208}Pb({pi}{sup {plus_minus}},{pi}{sup {plus_minus}}) data; analysis of {sup 206,207,208}Pb(p,p{prime}) data; study of transition nuclei by (p,p{prime}); search for recoil free {delta}-production; search for low lying magnetic states; proton nucleus scattering and swelling of nucleons; measurement of spin observables in {sup 28}Si(p,p{prime}); strength of tensor force in nuclei; global analysis of (p,p{prime}) reactions to high spin states in {sup 28}Si and {sup 58}Ni and density dependent modifications; MRS Setup and development; and development of coincidence studies with the MRS.
Date: July 1, 1990
Creator: Hintz, N. M.
Partner: UNT Libraries Government Documents Department

Is nuclear structure really so simple The P-factor revisited

Description: The parameter, P = N{sub p}N{sub n}/(N{sub p}+N{sub n}) is the number of valence protons (neutron) relative to the nearest shell or subshell closure, provides a simple and physically intuitive framework for understanding the evolution of collectivity in medium and heavy nuclei in terms of the competition between the spherical-driving, like-particle interaction and the deformation-driving, proton-neutron (p-n) interaction. In the past several years the P factor has been used to correlate a variety of properties of nuclear ground states and structures at low excitation energy. Here we present two new applications of this simple scheme: The isotopic systematics of 2{sub 1}{sup +} states and the linearization of intruder 0+ states in the Pb region. The results show the versatility of the P-factor as a simple embodiment of the competition and balance between the p-n and pairing residual interactions that seem to determine much of the behavior of ground and excited configurations of medium and heavy nuclei.
Date: January 1, 1992
Creator: Brenner, D. S. (Clark Univ., Worcester, MA (United States)); Casten, R. F. (Brookhaven National Lab., Upton, NY (United States)); Chou, W. T. (Clark Univ., Worcester, MA (United States) Brookhaven National Lab., Upton, NY (United States)) & Zhang, J. Y. (Brookhaven National Lab., Upton, NY (United States) Tennessee Univ., Knoxville, TN (United States) Institute of Modern Physics, Lanzhou, PRC (China))
Partner: UNT Libraries Government Documents Department

Status of heavy-lepton searches

Description: Searches for heavy leptons using e{sup +}e{sup -} annihilation, lepton-hadron collisions, photon-hadron collisions, hadron-hadron collisions, and studies of macroscopic matter are reviewed. The present experimental status and future possibilities are summarized.
Date: June 1, 1981
Creator: Perl, M.L.
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

Correlations between the production of prompt positrons at low transverse momentum and the associated charged multiplicity

Description: The production of prompt positrons in pp-collisions at ..sqrt..s = 63 GeV and y - 0 has been measured as a function of the associated charged particle multiplicity over the P/sub T/ internal 0.12 < P/sub T/ < 1.0 GeV/c. Preliminary results indicate that the production of positrons is proportional to the square of the mean multiplicity at low P/sub T/ (< 0.4 GeV/c). Such a square dependence is not expected from final state sources such as hadronic bremsstrahlung or hadronic decays. It could however indicate a production mechanism of the soft lepton continuum over an extensive volume during the early stages of the collision.
Date: January 1, 1986
Partner: UNT Libraries Government Documents Department

Charge symmetry breaking in the neutron proton system

Description: Two consequences of charge symmetry breaking (CSB) in the n-p system are examined. In n-p elastic scattering, CSB nuclear forces cause a difference between the polarizations of the neutron and the proton scattered in opposite directions in the center of mass system. The expected differences in polarizations due to one boson exchanges, particularly a photon exchange, isospin mixed mesons, and a pion (with the n-p mass difference taken into account), are computed. The calculated polarization difference is typically of the order of several tenths of a percent. In np ..-->.. d..pi../sup 0/, the CSB of nuclear forces can be tested by measuring the asymmetry of the angular distribution of deuterons about 90/sup 0/ in the center of mass frame. The expected asymmetry is calculated for one boson exchange CSB mechanisms, as in the elastic scattering. The asymmetry caused by the mixed n-..pi../sup 0/ exchange is dominant, but all of the mechanisms contribute asymmetries with similar angular dependences. The maximum assymmetry is about 0.8% at /sup 0/; the average is about 0.2%.
Date: December 1, 1979
Creator: Cheung, C.Y.; Henley, E.M. & Miller, G.A.
Partner: UNT Libraries Government Documents Department

Asymmetry measurements in PP elastic scattering during polarized beam acceleration up to 4. 4 GeV/c

Description: This is a brief report on the first measurement of the continuous momentum dependence of the analyzing power in proton-proton elastic scattering during polarized beam acceleration from 1.1 to 4.4 GeV/c. The measurement was done in the KEK-PS tunnel using an internal polyethylene thread target. The momentum bin size ranges from 5 to 18 MeV/c. Statistical uncertainty of the analyzing power is typically 0.5% per momentum bin. A small narrow structure has been observed at the incident proton momentum of 1.23 GeV/c. 2 refs., 4 figs.
Date: January 1, 1989
Creator: Shimizu, H.; Yoshida, H.; Ohnuma, H.; Kobayashi, Y.; Kobayashi, K.; Nakagawa, T. et al.
Partner: UNT Libraries Government Documents Department

High energy hadron--hadron collisions. Annual progress report. [Summaries of research activities at the University of Georgia]

Description: Work on high energy hadron collisions in the geometrical picture, performed under the ERDA Contract No. E(38-1)-946, is summarized. Comparisons with new experimental results are made. Specific items discussed include the hadronic matter distribution for mesons and the comparison of theoretical prediction with a recent experiment, the possible existence of a second minimum in elastic pp scattering at very high energies, the analysis of the energy dependence of opaqueness in pp collisions, and the study of spin effects in high energy polarized Kd elastic scattering.
Date: October 1, 1977
Creator: Chou, T.T.
Partner: UNT Libraries Government Documents Department

Medium energy measurements of N-N parameters

Description: This report discusses the following topics: Spin Transfer Measurements in np Elastic Scattering; KLL and P for np Elastic Scattering; Single Pion Production in np Scattering; Single Pion Production in np Scattering; and A New Search for Very Rate K{sub L}{degrees} Decays.
Date: November 30, 1991
Creator: Riley, P. J.
Partner: UNT Libraries Government Documents Department