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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

Structure functions: Their status and implications

Description: I discuss the current status of structure functions. Attention is given to the uncertainties in them and the implications of these uncertainties for experimental predictions. I indicate which experiments are capable of removing these uncertainties. 17 refs., 17 figs., 1 tab.
Date: September 29, 1988
Creator: Hinchliffe, I.
Partner: UNT Libraries Government Documents Department

Structure functions and parton distributions

Description: Activities of the structure functions and parton distributions group is summarized. The impact of scheme-dependence of parton distributions (especially sea-quarks and gluons) on the quantitative formulation of the QCD parton model is highlighted. Recent progress on the global analysis of parton distributions is summarized. Issues on the proper use of the next-to-leading parton distributions are stressed.
Date: April 1, 1991
Creator: Olness, F. (Oregon Univ., Eugene, OR (United States). Inst. of Theoretical Science) & Tung, Wu-Ki (Illinois Inst. of Tech., Chicago, IL (United States). Dept. of Physics)
Partner: UNT Libraries Government Documents Department

What we can learn from lepton-quark interactions

Description: A review is presented of what has been learned from lepton-quark interactions. Next, the context in which to ask future questions, the paradigm, it constitutes the set of assumptions that we believe on the basis of present experiments and which - subject always to refinement, extension, and revision - defines the way we talk about experiments done now and in the future. Two fothcoming neutrino experiments are discussed which seem to be of specific interest. Finally, some of the possibilities for experiments with ep colliders are covered. The point of that discussion is to try to understand what - in very general terms - are the things we may hope to learn from these facilities, and to begin to ask what requirements our physics questions place upon machines and experiments.
Date: July 1, 1981
Creator: Quigg, C.
Partner: UNT Libraries Government Documents Department

Producing [mu][sup [minus]]d and [mu][sup [minus]]t in vacuum

Description: After the feasibility of vacuum isolated [mu][sup -]d production was demonstrated at TRIUMF in 1989, development was begun on a target system that would take advantage of the process to aid in the understanding of the muon catalyzed fusion cycle. Minimal neutron backgrounds, the ability to use silicon detectors, and compatibility with tritium were considered important for a very versatile target system. the advantages which the target gives isolating [mu]CF process will be outlined.
Date: January 1, 1992
Creator: Knowles, P.E.; Beer, G.A.; Mason, G.R.; Olin, A. (Victoria Univ., BC (Canada)); Bailey, J.M. (Liverpool Univ. (United Kingdom)); Beveridge, J.L. et al.
Partner: UNT Libraries Government Documents Department

Photon structure function - theory

Description: The theoretical status of the photon structure function is reviewed. Particular attention is paid to the hadronic mixing problem and the ability of perturbative QCD to make definitive predictions for the photon structure function. 11 references.
Date: December 1, 1984
Creator: Bardeen, W.A.
Partner: UNT Libraries Government Documents Department

QCD phenomenology of parton distribution functions at small x

Description: The small x behavior of parton distributions is studied phenomenologically by examining in detail a series of QCD-evolved distribution sets obtained in a new global analysis of deep inelastic scattering and lepton-pair production experiments. The importance of 2-loop evolution is discussed. The main features and results of the global analysis are described. The range of small x behavior consistent with next-to-leading order QCD and current data is delineated. The extrapolated small x behavior is parameterized by effective Q-dependent power- and logarithmic-law parameters. Intriguing features of the evolution of these parameters with Q are presented. Alternative parametrizations based on the analytic solution for small x is also explored. 20 refs., 6 figs., 1 tab.
Date: September 1, 1990
Creator: Tung, Wu-Ki (Illinois Inst. of Tech., Chicago, IL (USA) Fermi National Accelerator Lab., Batavia, IL (USA))
Partner: UNT Libraries Government Documents Department