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Direct Interaction Neutrons from 14-Mev Inelastic Neutron Scattering

Description: Abstract: "Neutron nonelastic cross sections measured at different detector biases have been used to determine the cross sections for inelastically scattering 14 Mev neutrons into 9- to 14-Mev energy range. The cross section for producing these high energy neutrons, which may be attributed to direct interaction processes, is roughly 10% of the nonelastic cross section, for all elements. A comparison is made with data of Coon and co workers, who measured angular distributions for the same high-energy inelastically scattered-neutron group."
Date: May 19, 1958
Creator: MacGregor, Malcolm H.
Partner: UNT Libraries Government Documents Department

On the Relation Between Mechanisms for Single-Transverse-SpinAsymmetries

Description: Recent studies have shown that two widely-used mechanismsfor single-transverse-spin asymmetries based on either twist-threecontributions or on transverse-momentum-dependent (Sivers) partondistributions become identical in a kinematical regime of overlap. Thiswas demonstrated for the so-called soft-gluon-pole and hard-polecontributions to the asymmetry associated with a particular quark-gluoncorrelation function in the nucleon. In this paper, using semi-inclusivedeep inelastic scattering as an example, we extend the study to thecontributions by soft-fermion poles and by another independenttwist-three correlation function. We find that these additional termsorganize themselves in such a way as to maintain the mutual consistencyof the two mechanisms for single-spin asymmetries.
Date: November 5, 2007
Creator: Koike, Yuji; Vogelsang, Werner & Yuan, Feng
Partner: UNT Libraries Government Documents Department


Description: Calculational procedures oriented toward computer application are preserted to evaluate the neutron inelastic scattering cross section in the incoherent approximation for a simple cubic Bravais lattice. The differential scattering cross section, the scattering law, or inelastic scattering matrices and transport cross sections for multigroup calculations are evaluated using the contributions of 25 phonons. The inelastic scattering cross section for graphite is calculated as an example of polycrystalline media where the phonon-frequency distribution is dependent on the direction of polarization. (H.D.R.)
Date: September 1, 1962
Creator: Jankus, V.Z.
Partner: UNT Libraries Government Documents Department

Gamma Rays from Inelastic Scattering of 14-Mev Neutrons on Pb²⁰⁸

Description: Abstract: "The cross section for the production of 2.61-Mev gamma rays from the Pb-208(n, n')Pb-208* reaction has been measured for five different angles from 50 to 130 degrees. The angular distribution appears to be isotropic within the precision of the experiments, and leads to an integrated cross section of 25.5 +/- 4.6 millibarns."
Date: August 25, 1959
Creator: Hallett, Edward & Jensen, Roger
Partner: UNT Libraries Government Documents Department


Description: BS>Graphs were prepared as basic inelastic neutron data requested for neutron age calculations to be made using the compositions NaF-ZrF/sub 4/, BeF/ sub 2/, LiF-BeF/sub 2/, and ZrH. Nuclear temperature as a function of incident neutron energy was obtained for F, Be, and Zr. (W.D.M.)
Date: June 1, 1956
Creator: Copenhaver, C.M.
Partner: UNT Libraries Government Documents Department

Azimuthal Asymmetric Distribution of Hadrons Inside a Jet atHadron Collider

Description: We study the azimuthal asymmetric distribution of hadronsinside a high energy jet in the single transverse polarized proton protonscattering, coming from the Collins effect multiplied by the quarktransversity distribution. We argue that the Collins function in thisprocess is the same as that in the semi-inclusive deep inelasticscattering. The experimental study of this process will provide usimportant information on the quark transversity distribution and test theuniversality of the fragmentation functions.
Date: September 20, 2007
Creator: Yuan, Feng
Partner: UNT Libraries Government Documents Department

Nuclear structure studies with the inelastic neutron scattering rection and gamma-ray detection

Description: The (<i>n</i>, <i>n</i>´(gamma)) reaction has been used at the University of Kentucky accelerator facility to examine the detailed structure of a number of nuclei. The advantages of this method are reviewed, and recent developments are described. Examples of unique nuclear structure studies that have been carried out with this method are presented.
Date: December 10, 1998
Creator: Garrett, P. E.; Warr, N. & Yates, S. W.
Partner: UNT Libraries Government Documents Department

Theoretical description of heavy quark production in DIS

Description: We present results from a new event-generator Monte Carlo program for semi- inclusive DIS heavy quark production computed in a composite 3-flavor/4-flavor scheme, which is applicable over a wider range of energy scales than existing calculations. We compare the semi-inclusive distributions in p{sub t}, Q{sup 2} and W at O ({alpha}{sup 1}{sub s}) with recent HERA results. We also compare the inclusive F{sup charm}{sub 2} with the data and the existing O ({alpha}{sup 2}{sub s}) 3-flavor scheme calculation. Both calculations agree will with current HERA data, but the resummed O ({alpha}{sup 1}{sub s}) composite scheme calculation is simpler and more efficient by an order of magnitude.
Date: July 1, 1998
Creator: Amundson, J., FERMI
Partner: UNT Libraries Government Documents Department

Determination of sin{superscript 2} theta {subscript W} in neutrino-nucleon scattering at the NuTeV

Description: We report the determination of sin{sup 2}{theta}{sub W} in {nu}-N deep inelastic scattering from the NuTeV experiment. Using separate neutrino and anti-neutrino beams, NuTeV is able to extract sin{sup 2}{theta}{sub W} with low systematic errors from the Paschos-Wolfenstein variable R{sup -}, a ratio of differences of neutrino and anti-neutrino neutral-current and charged-current cross-sections. NuTeV measures sin{sup 2}{theta}{sub W} {sup (on - shell)} = 0.2253 {+-} 0.0019(stat) {+-} 0.0010(syst), which implies M{sub W}= 80.26 {+-} 0.11 GeV.
Date: April 29, 1999
Creator: al., R. Bernstein et
Partner: UNT Libraries Government Documents Department

Note on Nuclear Shadowing at Low Q{sup 2} and the Extraction of sin{sup 2} theta{sub w}

Description: In the light of a recent claim that models of nuclear shadowing which incorporate a vector meson dominance component at low Q{sup 2} are incompatible with nuclear deep inelastic scattering data, we compare the predictions of such a model with high precision data on the Q{sup 2} dependence of nuclear shadowing. Contrary to this claim, we find that models which incorporate both vector meson and partonic mechanisms are indeed consistent with both the magnitude and the Q{sup 2} slope of the shadowing data.
Date: August 1, 2002
Creator: Melnitchouk, Wally & Thomas, A.W.
Partner: UNT Libraries Government Documents Department


Description: For many years now, spin physics has played a very prominent role in QCD. The field has been carried by the hugely successful experimental program of polarized deeply-inelastic lepton-nucleon scattering (DIS), and by a simultaneous tremendous progress in theory. This talk summarizes some of the interesting new developments in spin physics in the past roughly two years. As we will see, there have yet again been exciting new data from polarized lepton-nucleon scattering, but also from the world's first polarized pp collider, RHIC. There have been very significant advances in theory as well. It will not be possible to cover all developments. The author will select those topics that may be of particular interest to the attendees of a conference in the ''DIS'' series. The author briefly reviews some of the recent developments in QCD spin physics.
Date: September 29, 2003
Partner: UNT Libraries Government Documents Department

Nuclear effects at HERA

Description: The development of a nuclear beam facility at HERA would allow the study of fundamental features of quark and gluon interactions in QCD. I briefly review the physics underlying nuclear shadowing and anti-shadowing as well as other diffractive and jet fragmentation processes that can be studies in high energy electron-nucleus collisions.
Date: July 1, 1996
Creator: Brodsky, S.J.
Partner: UNT Libraries Government Documents Department

How well do we know the neutron structure function?

Description: We present a detailed analysis of the uncertainty in the neutron F{sub 2}n structure function extracted from inclusive deuteron and proton deep-inelastic scattering data. The analysis includes experimental uncertainties as well as uncertainties associated with the deuteron wave function, nuclear smearing, and nucleon off-shell corrections. Consistently accounting for the Q{sup 2} dependence of the data and calculations, and restricting the nuclear corrections to microscopic models of the deuteron, we find significantly smaller uncertainty in the extracted F{sub 2}n/F{sub 2}p ratio than in previous analyses. In addition to yielding an improved extraction of the neutron structure function, this analysis also provides an important baseline that will allow future, model-independent extractions of neutron structure to be used to examine nuclear medium effects in the the deuteron.
Date: June 1, 2012
Creator: J. Arrington, J. G. Rubin, W. Melnitchouk
Partner: UNT Libraries Government Documents Department

Recent results in DIS from Jefferson Lab

Description: Recent results in Deep Inelastic processes measured at Jefferson Lab are presented. In addition to the inclusive reactions typically discussed in the context of Deep Inelastic (electron) Scattering, particular emphasis is given to Deep Exclusive and semi#19;inclusive reactions. Jefferson Lab has made significant contributions to the understanding of the partonic structure of the nucleon at large x, and with its first dedicated measurements is already providing important contributions to understanding the three-dimensional structure of the nucleon via constraints on Generalized Parton Distributions (GPDs) and Transverse Momentum Distributions (TMDs).
Date: April 1, 2010
Creator: Gaskell, David
Partner: UNT Libraries Government Documents Department

Hyperon Polarization in Unpolarized Scattering Processes

Description: Transverse polarization in the Hyperon (\Lambda) production in the unpolarizeddeep inelastic scattering and pp collisions is studied in the twist-three approach, considering the contribution from the quark-gluon-antiquark correlation distribution in nucleon. We further compare our results for deep inelastic scattering to a transverse momentum dependent factorization approach, and find consistency between the two approaches in the intermediate transverse momentum region. We also find that in pp collisions, there are only derivative terms contributions, and the non-derivative terms vanish.
Date: August 27, 2008
Creator: Zhou, Jian; Yuan, Feng & Liang, Zuo-Tang
Partner: UNT Libraries Government Documents Department


Description: Measurements of x{sub F}-dependent single spin asymmetries of identified charged hadrons, {pi}{sup {+-}}, K{sup {+-}}, p, and {bar p}, from transversely polarized proton collisions at {radical}s = 200 and 62.4 GeV at RHIC are presented. The energy and flavor dependent asymmetry measurements bring new insight into the fundamental mechanisms of transverse spin asymmetries and Quantum Chromodynamical description of hadronic structure.
Date: April 16, 2007
Partner: UNT Libraries Government Documents Department

The SISCone and anti-k_t jet algorithms

Description: We illustrate how the midpoint and iterative cone (with progressive removal) algorithms fail to satisfy the fundamental requirements of infrared and collinear safety, causing divergences in the perturbative expansion. We introduce SISCone and the anti-k{sub t} algorithms as respective replacements that do not have those failures without any cost at the experimental level.
Date: April 7, 2008
Creator: Soyez,G.
Partner: UNT Libraries Government Documents Department

Test of the Universality of Naive-time-reversal-odd Fragmentation Functions

Description: We investigate the&quot;spontaneous'' hyperon transverse polarization in e+e- annihilation and semi-inclusive deep inelastic scattering processes as a test of the universality of the naive-time-reversal-odd transverse momentum dependent fragmentation functions. We find that universality implies definite sign relations among various observables. This provides a unique opportunity to study initial/final state interaction effects in the fragmentation process and test the associated factorization.
Date: August 23, 2010
Creator: Boer, Daniel; Kang, Zhong-Bo; Vogelsang, Werner & Yuan, Feng
Partner: UNT Libraries Government Documents Department