286 Matching Results

Search Results

Advanced search parameters have been applied.

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

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

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

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

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

Data acquisition for FNAL E665

Description: The data acquisition system for FNAL E665, an experiment to study deep inelastic muon scattering from nucleons and nuclei, is described. The system is built with the FNAL VAXONLINE and RSX DA building blocks. The structure, capabilities and limitations for data flow, control and monitoring are discussed. 20 refs., 1 fig.
Date: January 1, 1989
Creator: Geesaman, D.F.; Green, M.C.; Kaufman, S.; Tentindo-Repond, S.; Bartlett, J.F.; Melanson, H.L. et al.
Partner: UNT Libraries Government Documents Department

On defining the un-definable: JETS

Description: A brief summary is presented of the current status of jet studies in hadron-hadron collisions. The primary focus is on those issues that would benefit from comparisons of jet samples obtained from hadron-hadron collisions, from e{sup +}e{sup {minus}} annihilation events at LEP and from deep inelastic collisions at HERA. The important point is that, to perform this comparison properly, the jet various samples must be obtained using the same jet definition.
Date: January 1, 1990
Creator: Ellis, S.D.
Partner: UNT Libraries Government Documents Department

Determination of sin/sup 2/THETA/sub w/ and rho in deep inelastic neutrino-nucleon scattering

Description: We have determined the electroweak parameters sin/sup 2/THETA/sub w/ and rho by a measurement of deep inelastic neutrino-nucleon scattering using a fine grained neutrino detector exposed to a narrow band neutrino beam at Fermilab. The unique sampling properties of our detector have permitted neutral current and charged current events to be unambiguously identified over a wide kinematic range, thereby allowing a determination of sin/sup 2/THETA/sub w/ and rho to be made with good statistics and small systematic errors. We have found sin/sup 2/THETA/sub w/ = 0.246 +- 0.012 +- 0.013 in a single parameter fit. The details of the experimental and theoretical systematic errors are given. 17 refs., 2 figs., 2 tabs.
Date: June 1, 1985
Creator: Bogert, D.; Burnstein, R.; Fisk, R.; Fuess, S.; Morfin, J.; Ohska, T. et al.
Partner: UNT Libraries Government Documents Department

Impact of the e-p option on Isabelle experimental areas

Description: There have been many suggestions for the expansion of existing or planned storage rings to include high energy e-p collisions. We will not discuss the physics potential here, but there is a general concensus that a facility with protons colliding with electrons and positrons of selectible helicity would provide great insight into weak interactions, nucleon structure, etc., in a way not duplicated at e/sup +/e/sup -/, pp, nor anti pp machines. In this report, some aspects of the addition of a 10 to 20 GeV electron ring to Isabelle are discussed.
Date: January 1, 1981
Creator: Foley, K.J.; Kantardjian, G.; Lanou, R.; Paar, H. & Stevens, A.
Partner: UNT Libraries Government Documents Department

Impact of the e-p option on ISABELLE experimental areas

Description: There have been many suggestions for the expansion of existing or planned storage rings to include high energy e-p collisions. There is a general concensus that a facility with protons colliding with electrons and positrons of selectible helicity would provide great insight into weak interactions, nucleon structure, etc., in a way not duplicated at e/sup +/e/sup -/, pp nor anti pp machines. Some aspects of the addition of a 10 to 20 GeV electron ring to Isabelle are discussed.
Date: January 1, 1981
Creator: Foley, K.J.; Kantardjian, G.; Lanou, R.; Paar, H & Stevens, A.
Partner: UNT Libraries Government Documents Department

Twist-four effects in deep inelastic neutrino scattering and sinStheta/sub w/

Description: In addition to the standard perturbative QCD corrections to deep inelastic scattering, there are nonperturbative twist-four corrections which behave like 1/QS relative to the lnQS leading log corrections. We have calculated the twist-four, spin-one and spin-two corrections to sigma/sub NC/, sigma/sub CC/, R/sub nu/ and R/sub anti nu/ using the following procedure: The bilocal product of the weak currents is expanded into local operators using the Wilson operator product expansion. The coefficient functions obey the renormalization group equations and, neglecting the anomalous dimensions of the operators, were calculated using perturbative techniques. The nucleon matrix elements of the local operators can then be evaluated assuming some quark confinement model. We found that twist-four, spin-two corrections to the neutral current neutrino scattering decreases sinStheta/sub w/ by about 1%. Taking into account the twist-four, spin-two corrections for the charged current cross section, we found that they give a dominant contribution to the ratio R/sub nu/ and increased sinStheta/sub w/ by about 0.5%. We also have studied the model dependence of our results, and we have found that the twist-four, spin-two corrections to sinStheta/sub w/ are quite model dependent. The twist-four, spin-one corrections to the neutrino scattering were also calculated. These corrections come from two-quark, one-gluon operators and even at low QS their contribution was found to be considerably smaller than the twist-four, spin-two corrections.
Date: July 1, 1985
Creator: Fajfer, S. & Oakes, R.J.
Partner: UNT Libraries Government Documents Department

Azimuthal energy flow in deep inelastic neutrino scattering

Description: Gluon emission and the transverse momentum (p/sub t/) of partons confined in nucleons were studied using deep-inelastic charged-current neutrino-nucleon interactions. For this analysis we use the flow of hadronic energy in the azimuthal direction around the momentum transfer referenced from the neutrino-muon scattering plane. A five standard deviation asymmetry was found. Analysis of this asymmetry indicates a (p/sub t/) of 0.35 +- 0.12 GeV/c if QCD corrections are included, and 0.56 +- 0.05 GeV/c if they are excluded. Some evidence was also observed for x dependence in p/sub t/. Data were taken at Fermilab in 1982 using a 200 ton (fiducial mass) fine grained calorimeter and a dichromatic neutrino beam.
Date: June 12, 1986
Creator: Mukherjee, A.; Bofill, J.; Busza, W.; Eldridge, T.F.; Friedman, J.I.; Fuess, S. et al.
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