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Polarized lepton-nucleon scattering

Description: Deep inelastic polarized lepton-nucleon scattering is reviewed in three lectures. The first lecture covers the polarized deep inelastic scattering formalism and foundational theoretical work. The second lecture describes the nucleon spin structure function experiments that have been performed up through 1993. The third lecture discusses implication of the results and future experiments aimed at high-precision measurements of the nucleon spin structure functions.
Date: February 1, 1994
Creator: Hughes, E.
Partner: UNT Libraries Government Documents Department

Nuclear effects in deep inelastic scattering

Description: The authors extend the approach used to treat quasi-elastic inclusive electron-nucleus scattering to the deep inelastic region. They provide a general approach to describe lepton scattering from an off-shell nucleon, and calculate the ratio of inclusive deep inelastic scattering cross sections to the deuteron for nuclear matter and helium (EMC-effect). They find that the consistent inclusion of the binding effects, in particular the ones arising from the short-range nucleon-nucleon interaction, allows to describe the data in the region of x > 0.15 where binding fully accounts for the deviation of the cross section ratios from one.
Date: March 1, 1998
Creator: Benhar, O.; Pandharipande, V.R. & Sick, I.
Partner: UNT Libraries Government Documents Department

Finite temperature wave-function renormalization, a comparative analysis

Description: We compare two competing theories regarding finite temperature wave-function corrections for the process H {r_arrow} e{sup +}e{sup {minus}} and for n + {nu} {r_arrow} p + e{sup {minus}} and related processes of interest for primordial nucleosynthesis. Although the two methods are distinct (as shown in H {r_arrow} e{sup +}e{sup {minus}}) they yield the same finite temperature correction for all n {r_arrow} p and p {r_arrow} n processes. Both methods yield an increase in the He/H ratio of 0.01% due to finite temperature renormalization rather than a decrease of 0.16% as previously predicted. 6 refs., 3 figs.
Date: December 31, 1996
Creator: Chapman, I. A.
Partner: UNT Libraries Government Documents Department

The spin of the nucleon in deep inelastic lepton scattering experiments

Description: The current experimental status of the spin dependent structure functions as measured in polarized deep inelastic scattering of charged leptons from nucleons is reviewed. The proposals for new experiments at CERN, SLAC and HERA are discussed with special emphasis on the experiment of the Spin Muon collaboration at CERN which has started data taking.
Date: September 1, 1992
Creator: Mallot, G. K.
Partner: UNT Libraries Government Documents Department

Experimental results on polarized structure functions in deep inelastic lepton-nucleon scattering

Description: A summary is given of experimental results on spin structure functions of the proton g{sub 1}{sup p}(x,Q{sup 2}), deuteron g{sub 1}{sup d}(x,Q{sup 2}), and neutron g{sub 1}{sup n}(x,Q{sup 2}) as measured in deep inelastic scattering of polarized leptons from a polarized target. All results are consistent with the Bjorken sum rule predictions at the Q{sup 2} of each experiment. The data do not support the Ellis-Jaffe sum rule prediction for the proton which implies that the hencity carried by the strange quark may be nonzero and that the net quark helicity is smaller than expected from simple quark models.
Date: August 1, 1994
Creator: Stuart, L.
Partner: UNT Libraries Government Documents Department

Same-Sign Dilepton Production by Neutrinos

Description: There has been considerable experimental work on same-sign dilepton production in neutrino interactions over the past 10 years. However, the situation is still unclear. Most experiments do have evidence for an excess of candidates but there is a lack of independent statistically significant results. Present experiments at the Tevatron may provide important new information. However the recent revision of older results and the lower rates from recent experiments indicate that real progress will be difficult. Furthermore, the problems encountered with ..pi../K background subtractions argue for a multi-target experiment. Also, given the conflict with present c anti c calculations, a high statistics bubble chamber experiment would be useful to establish the presence/absence of c anti c events at the presently measured production rates. 13 refs., 6 figs., 2 tabs.
Date: November 7, 1985
Creator: Murtagh, Michael J.
Partner: UNT Libraries Government Documents Department

Elastic scattering of muon neutrinos at BNL

Description: In this paper measurement of the purely leptonic reactions: nu/sub ..mu../e ..-->.. nu/sub ..mu../e and anti nu/sub ..mu../e ..-->.. anti nu/sub ..mu../e, and the semileptonic reactions: nu/sub ..mu../p ..-->.. nu/sub ..mu../p and anti nu/sub ..mu../p ..-->.. anti nu/sub ..mu../p are presented and discussed in terms of the standard model. The data also places limites of interest on the magnitudes of a possible neutrino charge radius and a neutrino magnetic moment.
Date: February 1, 1987
Creator: Abe, K.; Ahrens, L.A.; Amako, K.; Aronson, S.H.; Beier, E.W.; Callas, J.L. et al.
Partner: UNT Libraries Government Documents Department

Production of like sign dimuon events by neutrinos

Description: A sample of 46 ..mu../sup -/..mu../sup -/ events was obtained in studying high energy neutrino interactions at Fermilab. The analysis of these data yields a prompt rate, N/sup prompt/(..mu../sup -/..mu../sup -/)/N/sup prompt/(..mu../sup -/..mu../sup +/), of 0.12 +- 0.05 for P/sub ..mu../ > 10 GeV/c. The ..mu../sup -/..mu../sup -/ events are predominately of hadronic origin. 9 references.
Date: January 1, 1978
Creator: Gilchriese, M.G.D.
Partner: UNT Libraries Government Documents Department

Nuclear dependence of structure functions in the shadowing region of deep inelastic scattering

Description: A discussion of nuclear shadowing in deep inelastic lepton scattering is presented. We show that the parton recombination model suggests that shadowing should begin to occur at larger values of Bjorken x as A increases. This expectation as well as that of weak dependence on Q/sup 2/, and the trend of the x dependence of the shadowing phenomenon are consistent with recent data. Shadowing at small x is combined with nuclear bound state effects, responsible for nuclear dependence at larger x, to provide description of the A dependence of the structure function for the entire range of x. 21 refs., 5 figs.
Date: July 27, 1988
Creator: Berger, E.L. & Qiu, Jianwei
Partner: UNT Libraries Government Documents Department

Calorimetry in ZEUS: Lessons for the future

Description: The storage ring facility HERA, under construction at the DESY Laboratory, will collide 30 GeV e/sup /minus// with 820 GeV protons when the machine is first turned on in 1990. Four interaction regions being provided. Subsequently either e/sup /minus// or e beams can be used and a facility for producing longitudinal polarization of the electrons at the interaction points will be provided. Both the center-of-mass energy ( s = 314 GeV) and the momentum transfer (Q/sub max/S /approximately/ 10V GeVS) are substantially higher than in any deep inelastic scattering studies to date. The HERA program will be the natural extension of both the neutrino and the muon scattering experiments done at CERN and Fermilab. With the design luminosity of 1.5 10T cm/sup /minus/2/ sec/sup /minus/1/ experiments with 200 pb/sup /minus/1/ of integrated luminosity will be possible. HERA will be the first electron-quark collider. The energy is substantially higher than LEP, and the events will be cleaner than those resulting from p/bar p/ collisions. It provides the third leg that will support the physics stool of the 1990s. In neutral current events, the z exchange graph is comparable in strength to the photon exchange and the charged current events will provide unique insights into the W coupling. There will be substantial rates of heavy quark production. Two detectors are under construction: H1 uses a large solenoid with a liquid argon calorimeter inside the coil, ZEUS uses a smaller magnet with uranium-scintillator calorimeters outside of the coil. 4 refs., 11 figs.
Date: January 1, 1988
Creator: Derrick, M.
Partner: UNT Libraries Government Documents Department

W- and Z-boson production at ep colliders

Description: We briefly summarize the results of a comprehensive study of W and Z production in high energy ep collisions. The processes ep [yields] vWX[sup [plus minus]]X, ep [yields] vW[sup [minus]]X, ep [yields] eZX and ep [yields] vZX are investigated. The region of small momentum transfer in eW and eZ production, with a fermion exchanged in the u-channel, is treated using the photon structure function approach, and carefully matched to the deep inelastic region. Low momentum photon exchange contributions to vW and eZ production, where the proton either stays intact or is transformed into a nucleon resonance, are calculated using form factors and structure functions fitted directly to experimental data.
Date: April 1, 1992
Creator: Baur, U.
Partner: UNT Libraries Government Documents Department

Is there a way to measure the deep-inelastic cross-section using wide-band neutrino beams

Description: A method is described for extracting the value of the neutrino flux in a wide-band beam exposure based on computed differential cross-sections for resonance production and quasielastic scattering of neutrinos on nucleons. The resonance production cross-sections, computed by means of a relativistic quark model, are in excellent agreement with measurements of various neutrino-induced exclusive final states performed so far and also with data from inclusive deep-inelastic neutrino interactions. The theoretical uncertainty inherent in the method is estimated to be about 10% and is roughly equal to the systematic error which plagues the measurements of the neutrino flux in present-day narrow-band beams. Before the first Tevatron narrow-band beam data becomes available in a few years time, if at all, this method provides the only reliable way of ''measuring'' the total neutrino cross-section with the existing wide-band beam data, thus extending the measured energy range by nearly a factor of two.
Date: January 1, 1987
Creator: Belusevic, R. & Rein, D.
Partner: UNT Libraries Government Documents Department

A possible early experimental test for a large G(x,QS)

Description: A proposal that the net spin carried by gluons in a polarized proton may be very large compared to 1/2 has recently received considerable theoretical attention. There exists a unique opportunity to test for this dramatic possibility using an existing experimental setup. We urge the consideration of a precision measurement (+-10 b) of sigma/sub L//sup jet/(pp; p0, s) at p0S = 5 GeVS and s = 400 GeVS using the Fermilab polarized beam facility. 10 refs.
Date: October 6, 1988
Creator: Sivers, D. & Ramsey, G.
Partner: UNT Libraries Government Documents Department

Heavy quark production in ep collisions at HERA. [None]

Description: There are substantial production rates of heavy quarks from ep collisions at HERA. The center of mass energy of about 300 GeV is well above any b-quark threshold effects, and for b/bar b/ production, the cross section is estimated to be 3.3 nb per event, leading to rates approaching 10/sup 6/ b mesons per year. The rates for c/bar c/ production are about two orders of magnitude greater. Two major detectors are under construction and a program of heavy quark physics will start in 1990. 3 refs., 4 figs.
Date: December 22, 1987
Creator: Derrick, M.
Partner: UNT Libraries Government Documents Department

Electron--proton interactions at ISABELLE. [Possible experimental parameters, 400 GeV, cross sections, kinematics]

Description: A calculation of kinematics and cross sections is done for an investigation of the physics possibilities specific to the study of weak interactions in electron-proton interactions at Isabelle at 400 GeV, with an electron/positron storage ring of 20 GeV. (JFP)
Date: August 30, 1977
Creator: Limon, P.J. & Humphrey, J.W.
Partner: UNT Libraries Government Documents Department

Triple gluon coupling, Adler-Bell-Jackiw anomaly, and polarized deep inelastic scattering

Description: An unusual effect of triple gluon coupling and the Adler-Bell-Jackiw anomaly on the flavor singlet part of the polaried deep inelastic scattering structure function ..nu..G/sub 1/(Q/sup 2/,x) are discussed. Namely, the x-integral I/sub S/(Q/sup 2/) of this function is Q/sup 2/-independent both in parton model and leading logarithm calculations, but the first order nonleading logarithm calculation produces a term growing like (-lnlnQ/sup 2/), dominating over the parton model contributions at large Q/sup 2/. The detection of this unusual term will amount to an experimental confirmation of the existence of triple gluon coupling and the Adler-Bell-Jackiw anomaly. Technically, this term comes from a new axial vector gluon operator which is introduced in the Wilson expansion. Other results of this paper include a discussion of mass-sensitive and mass-insensitive structure functions and the derivation of the expression for, and the relations between, some of these structure functions.
Date: May 1, 1980
Creator: Lam, C.S. & Li, B.A.
Partner: UNT Libraries Government Documents Department

Possibility of detecting triple gluon coupling and Adler-Bell-Jackiw anomaly in polarized deep inelastic scattering

Description: A way to detect experimentally the existence of triple gluon coupling and the Adler-Bell-Jackiw anomaly is to measure the Q/sup 2/-dependence of polarized deep inelastic scattering. These effects lead to a ln ln Q/sup 2/ term which we calculate by introducing a new gluon operator in the Wilson expansion.
Date: May 1, 1980
Creator: Lam, C.S. & Li, B.A.
Partner: UNT Libraries Government Documents Department

Transverse spin observables in chromodynamics

Description: Quantum Chromodynamics confronts a harsh series of tests in the attempt to formulate a comprehensive approach to the calculation of transverse spin observables. The basic obstacles to understanding transverse spin can be illustrated by considering the transverse structure function g{sub T}(x, Q{sup 2}) = g{sub 1}(x, Q{sup 2}) + g{sub 2}(x, Q{sup 2}), extracted from deep-inelastic scattering using a polarized lepton and a polarized proton. The inadequacy of the transverse-spin basis for quarks and gluons found there suggests a new approach to the problems of single-spin observables in large-transverse-momentum processes. This approach, presented earlier for single spin production asymmetries, is discussed here. It is shown that the mechanism can also lead to baryon polarization effects at large P{sub T}. 14 refs.
Date: December 1, 1989
Creator: Sivers, D.
Partner: UNT Libraries Government Documents Department