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Measuring the flavor asymmetry in the sea quarks of the proton

Description: The proton is a composite object made of fundamental, strongly-interacting quarks. Many of the features of the proton can be described by a simple picture based on three valence quarks bound by the exchange of gluons. However, protons are much more complex objects with the vast majority of their mass dynamically generated by Quantum Chromodynamics (QCD). This mass manifests itself through a 'sea' of gluons and quark-antiquark pairs. By measuring Drell-Yan scattering, the Fermilab E-906/SeaQuest… more
Date: January 1, 2010
Creator: Reimer, Paul E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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AdS/QCD, Light-Front Holography, and Sublimated Gluons

Description: The gauge/gravity duality leads to a simple analytical and phenomenologically compelling nonperturbative approximation to the full light-front QCD Hamiltonian - 'Light-Front Holography', which provides a Lorentz-invariant first-approximation to QCD, and successfully describes the spectroscopy of light-quark meson and baryons, their elastic and transition form factors, and other hadronic properties. The bound-state Schroedinger and Dirac equations of the soft-wall AdS/QCD model predict linear Re… more
Date: February 16, 2012
Creator: Brodsky, Stanley J. & de Teramond, Guy F.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Gluons and the Quark Sea at High Energies: Distributions, Polarization, Tomography

Description: This report on the science case for an Electron-Ion Collider (EIC) is the result of a ten-week program at the Institute for Nuclear Theory (INT) in Seattle (from September 13-November 19, 2010), motivated by the need to develop a strong case for the continued study of the QCD description of hadron structure in the coming decades. Hadron structure in the valence quark region will be studied extensively with the Jefferson Lab 12 GeV science program, the subject of an INT program the previous year… more
Date: June 7, 2012
Creator: Boer, Daniel; Diehl, Markus; Milner, Richard; Venugopalan, Raju; Vogelsang, Werner; Kaplan, David et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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kt-factorization for Hard Processes in Nuclei

Description: Two widely proposed kt-dependent gluon distributions in the small-x saturation regime are investigated using two particle back-to-back correlations in high energy scattering processes. The Weizsacker-Williams gluon distribution, interpreted as the number density of gluon inside the nucleus, is studied in the quark-antiquark jet correlation in deep inelastic scattering. On the other hand, the unintegrated gluon distribution, defined as the Fourier transform of the color-dipole cross section, is … more
Date: September 13, 2010
Creator: Dominguez, Fabio; Xiao, Bo-Wen & Yuan, Feng
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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First Search for the Standard Model Higgs Boson Using the Semileptonic Decay Channel: H --> WW --> mu bar nu jj

Description: This dissertation presents the first search for the standard model Higgs boson (H) in decay topologies containing a muon, an imbalance in transverse momentum (E{sub T}) and jets, using p{bar p} collisions at {radical}s = 1.96 TeV with an integrated luminosity of 4.3 fb{sup -1} recorded with the D0 detector at the Fermilab Tevatron Collider. This analysis is sensitive primary to contributions from Higgs bosons produced through gluon fusion, with subsequent decay H {yields} WW {yields} {mu}{nu}jj… more
Date: September 1, 2010
Creator: Zelitch, Shannon Maura & U., /Virginia
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
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Probing the Linear Polarization of Gluons in Unpolarized Hadrons at EIC

Description: Gluons inside unpolarized hadrons can be linearly polarized provided they have a nonzero transverse momentum. The simplest and theoretically safest way to probe this TMD distribution of linearly polarized gluons is through cos 2{phi} asymmetries in heavy quark pair or dijet production in electron-hadron collisions. Future EIC or LHeC experiments are ideally suited for this purpose. Here we estimate the maximum asymmetries for EIC kinematics.
Date: August 17, 2011
Creator: Boer, Daniel; Brodsky, Stanley J.; Mulders, Piet J. & Pisano, Cristian
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Transversity from First Principles in QCD

Description: Transversity observables, such as the T-odd Sivers single-spin asymmetry measured in deep inelastic lepton scattering on polarized protons and the distributions which are measured in deeply virtual Compton scattering, provide important constraints on the fundamental quark and gluon structure of the proton. In this talk I discuss the challenge of computing these observables from first principles; i.e.; quantum chromodynamics, itself. A key step is the determination of the frame-independent light… more
Date: February 16, 2012
Creator: Brodsky, Stanley J. & /SLAC /Southern Denmark U., CP3-Origins
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Electroweak Baryogenesis and Colored Scalars

Description: We consider the 2-loop finite temperature effective potential for a Standard Model-like Higgs boson, allowing Higgs boson couplings to additional scalars. If the scalars transform under color, they contribute 2-loop diagrams to the effective potential that include gluons. These 2-loop effects are perhaps stronger than previously appreciated. For a Higgs boson mass of 115 GeV, they can increase the strength of the phase transition by as much as a factor of 3.5. It is this effect that is responsi… more
Date: February 15, 2012
Creator: Cohen, Timothy; /SLAC /Michigan U., MCTP; Pierce, Aaron & /Michigan U., MCTP
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Opportunities for Drell-Yan Physics at RHIC

Description: Drell-Yan (DY) physics gives the unique opportunity to study the parton structure of nucleons in an experimentally and theoretically clean way. With the availability of polarized proton-proton collisions and asymmetric d+Au collisions at the Relativistic Heavy Ion Collider (RHIC), we have the basic (and unique in the world) tools to address several fundamental questions in QCD, including the expected gluon saturation at low partonic momenta and the universality of transverse momentum dependent … more
Date: May 24, 2011
Creator: Aschenauer, E.; Bland, L.; Crawford, H.; Goto, Y.; Eyser, O.; Kang, Z. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Search for the standard model Higgs boson in tau lepton pair final states

Description: We present a search for the standard model Higgs boson in final states with an electron or muon and a hadronically decaying tau lepton in association with zero, one, or two or more jets using data corresponding to an integrated luminosity of up to 7.3 fb{sup -1} collected with the D0 detector at the Fermilab Tevatron collider. The analysis is sensitive to Higgs boson production via gluon gluon fusion, associated vector boson production, and vector boson fusion, and to Higgs boson decays to tau … more
Date: March 1, 2012
Creator: Abazov, Victor Mukhamedovich & al., et
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Summary of “Future of DIS” Working Group Session

Description: Despite the closure of the HERA accelerator in the past few years, much physics still remains to be understood, from the quark and gluon content of the nucleon/nucleus across all x to the still unknown spin structure of the proton. The 'Future of DIS' working group was dedicated to discussions on these and many other subjects. This paper represents a brief overview of the discussions. For further details, please refer to individual contributions.
Date: April 11, 2011
Creator: M., Lamont; Guzey, V. & Polini, A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Inclusive hadron distributions in p+p collisions from saturation models of HERA DIS data.

Description: Dipole models based on various saturation scenarios provide reasonable fits to small-x DIS inclusive, diffractive and exclusive data from HERA. Proton un-integrated gluon distributions extracted from such fits are employed in a k{sub {perpendicular}}-factorization framework to calculate inclusive gluon distributions at various energies. The n-particle multiplicity distribution predicted in the Glasma flux tube approach shows good agreement with data over a wide range of energies. Hadron inclusi… more
Date: December 6, 2010
Creator: Tribedy, P. & Venugopalan, R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Hiding a Heavy Higgs Boson at the 7 TeV LHC

Description: A heavy Standard Model Higgs boson is not only disfavored by electroweak precision observables but is also excluded by direct searches at the 7 TeV LHC for a wide range of masses. Here, we examine scenarios where a heavy Higgs boson can be made consistent with both the indirect constraints and the direct null searches by adding only one new particle beyond the Standard Model. This new particle should be a weak multiplet in order to have additional contributions to the oblique parameters. If it … more
Date: March 20, 2012
Creator: Bai, Yang; Fan, JiJi & Hewett, JoAnne L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Excited Baryons in Holographic QCD

Description: The light-front holographic QCD approach is used to describe baryon spectroscopy and the systematics of nucleon transition form factors. Baryon spectroscopy and the excitation dynamics of nucleon resonances encoded in the nucleon transition form factors can provide fundamental insight into the strong-coupling dynamics of QCD. The transition from the hard-scattering perturbative domain to the non-perturbative region is sensitive to the detailed dynamics of confined quarks and gluons. Computation… more
Date: November 8, 2011
Creator: de Teramond, Guy F.; U., /Costa Rica; Brodsky, Stanley J. & /SLAC /Southern Denmark U., CP3-Origins
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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New Perspectives for QCD Physics at the LHC

Description: I review a number of topics where conventional wisdom relevant to hadron physics at the LHC has been challenged. For example, the initial-state and final-state interactions of the quarks and gluons entering perturbative QCD hard-scattering subprocesses lead to the breakdown of traditional concepts of factorization and universality for transverse-momentum-dependent observables at leading twist. These soft-gluon rescattering effect produce single-spin asymmetries, the breakdown of the Lam-Tung re… more
Date: February 7, 2011
Creator: Brodsky, Stanley J. & /SLAC /Stanford U. /Southern Denmark U., CP3-Origins
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Gluons and the quark sea at high energies: distributions, polarization, tomography

Description: This report is based on a ten-week program on Gluons and the quark sea at high-energies, which took place at the Institute for Nuclear Theory (INT) in Seattle in Fall 2010. The principal aim of the program was to develop and sharpen the science case for an Electron-Ion Collider (EIC), a facility that will be able to collide electrons and positrons with polarized protons and with light to heavy nuclei at high energies, offering unprecedented possibilities for in-depth studies of quantum chromody… more
Date: September 30, 2011
Creator: Boer, D.; Venugopalan, R.; Diehl, M.; Milner, R.; Vogelsang, W. & al., et
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Strongly Interacting Matter Matter at Very High Energy Density: 3 Lectures in Zakopane

Description: These lectures concern the properties of strongly interacting matter at very high energy density. I begin with the Color Glass Condensate and the Glasma, matter that controls the earliest times in hadronic collisions. I then describe the Quark Gluon Plasma, matter produced from the thermalized remnants of the Glasma. Finally, I describe high density baryonic matter, in particular Quarkyonic matter. The discussion will be intuitive and based on simple structural aspects of QCD. There will be som… more
Date: June 9, 2010
Creator: McLerran, L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Precision measurements of the top quark mass and width with the D0 detector

Description: Since the discovery of the top quark in 1995 at the Fermliab Tevatron Collider, top quark properties have been measured with ever higher precision. In this article, recent measurements of the top quark mass and its width using up to 3.6 fb{sup -1} of D0 data are summarized. Different techniques and final states have been examined and no deviations within these measurements have been observed. In addition to the direct measurements, a measurement of the top quark mass from its production cross s… more
Date: January 1, 2010
Creator: Grohsjean, Alexander & /IRFU, SPP, Saclay
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Spin-Flavor van der Waals Forces and NN interaction

Description: A major goal in Nuclear Physics is the derivation of the Nucleon-Nucleon (NN) interaction from Quantum Chromodynamics (QCD). In QCD the fundamental degrees of freedom are colored quarks and gluons which are confined to form colorless strongly interacting hadrons. Because of this the resulting nuclear forces at sufficiently large distances correspond to spin-flavor excitations, very much like the dipole excitations generating the van der Waals (vdW) forces acting between atoms. We study the Nucl… more
Date: December 1, 2011
Creator: Alvaro Calle Cordon, Enrique Ruiz Arriola
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Medium Modification of Vector Mesons

Description: The theory of the strong interaction, Quantum Chromodynamics (QCD), has been remarkably successful in describing high-energy and short-distance-scale experiments involving quarks and gluons. However, applying QCD to low energy and large-distance scale experiments has been a major challenge. Various QCD-inspired models predict a partial restoration of chiral symmetry in nuclear matter with modifications of the properties of hadrons from their free-space values. Measurable changes such as a shift… more
Date: March 1, 2011
Creator: Chaden Djalali, Michael Paolone, Dennis Weygand, Michael H. Wood, Rakhsha Nasseripour
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Physics Opportunities of a Fixed-Target Experiment using the LHC Beams

Description: We outline the many physics opportunities offered by a multi-purpose fixed-target experiment using the proton and lead-ion beams of the LHC extracted by a bent crystal. In a proton run with the LHC 7-TeV beam, one can analyze pp, pd and pA collisions at center-of-mass energy {radical}s{sub NN} {approx_equal} 115 GeV and even higher using the Fermi motion of the nucleons in a nuclear target. In a lead run with a 2.76 TeV-per-nucleon beam, {radical}s{sub NN} is as high as 72 GeV. Bent crystals ca… more
Date: March 16, 2012
Creator: Brodsky, S.J.; /SLAC; Fleuret, F.; Polytechnique, /Ecole; Hadjidakis, C.; Lansberg, J.P. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Physics Prospects with GlueX

Description: The new experiment GlueX is being currently constructed at Jefferson Lab. The experiment was designed to search for hybrid mesons with exotic-quantum-numbers using a beam of linearly polarized photons incident on a liquid hydrogen target. We will discuss the discovery potential of the GlueX experiment and briefly overview its physics program. GlueX is a new experiment at Jefferson Lab. whose physics program is intended to improve our knowledge of strong interactions. The main goal of the experi… more
Date: October 1, 2011
Creator: Somov, Alexander
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Observation of the doubly strange b-Baryon Omega(b)-

Description: This thesis reports the first experimental evidence of the doubly strange b-baryon {Omega}{sub b}{sup -} (ssb) following the decay channel {Omega}{sub b}{sup -} {yields} J/{psi}(1S) {mu}{sup +}{mu}{sup -} {Omega}{sup -} {Lambda} K{sup -} p {pi}{sup -} in p{bar p} collisions at {radical}s = 1.96 Tev. Using approximately 1.3 fb{sup -1} of data collected with the D0 detector at the Fermilab Tevatron Collider, they observe 17.8 {+-} 4.9(stat) {+-} 0.8(syst) {Omega}{sub b}{sup -} signal events at 6.… more
Date: February 1, 2011
Creator: Hernandez Orduna, de Jesus, Jose
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
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Polarized proton beams in RHIC

Description: The polarized beam for RHIC is produced in the optically-pumped polarized H{sup -} ion source and then accelerated in Linac to 200 MeV for strip-injection to Booster and further accelerated 24.3 GeV in AGS for injection in RHIC. In 2009 Run polarized protons was successfully accelerated to 250 GeV beam energy. The beam polarization of about 60% at 100 GeV beam energy and 36-42% at 250 GeV beam energy was measured with the H-jet and p-Carbon CNI polarimeters. The gluon contribution to the proton… more
Date: October 4, 2010
Creator: Zelenski, A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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