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Phases of QCD: Summary of the Rutgers Long Range Plan Town Meeting, January 12-14, 2007

Description: This White Paper summarizes the outcome of the Town Meeting on Phases of QCD that took place January 12-14, 2007 at Rutgers University, as part of the NSAC 2007 Long Range Planning process. The meeting was held in conjunction with the Town Meeting on Hadron Structure, including a full day of joint plenary sessions of the two meetings. Appendix A.1 contains the meeting agenda. This Executive Summary presents the prioritized recommendations that were determined at the meeting. Subsequent chapters present the essential background to the recommendations. While this White Paper is not a scholarly article and contains few references, it is intended to provide the non-expert reader
Date: May 14, 2007
Creator: Jacobs, Peter; Kharzeev, Dmitri; Muller, Berndt; Nagle, Jamie; Rajagopal, Krishna & Vigdor, Steve
Partner: UNT Libraries Government Documents Department

Summary and highlights of the 14th Topical Conference on Hadron Collider Physics (HCP2002)

Description: First of all, I would like to thank the scientific committee, the conference organizers, the University of Karlsruhe and the Institute for Experimental Nuclear Physics, all of the speakers, and the conference secretariat, for making this an extremely well-organized and uniformly high-quality meeting. I would also like to thank all of the speakers who provided me with material for my talk before and during the conference. There is obviously no point in these proceedings in attempting to repeat all of the material from the individual contributions; by definition, these are all available earlier in this volume. In the written version, therefore, I will try to give a high level overview of the current state of hadron collider physics and to highlight the connections between the many presentations at this conference.
Date: November 13, 2002
Creator: Womersley, John
Partner: UNT Libraries Government Documents Department

Drell-Yan Lepton Pair Azimuthal Asymmetry in Hadronic Processes

Description: We study the azimuthal asymmetry in the Drell-Yan lepton pair production in hadronic scattering processes at moderate transverse momentum region, taking into account the contributions from the twist-three quark-gluon correlations from the unpolarized hadrons. The contributions are found to dominate the asymmetry, and are not power suppressed by qt/Q at small qt where qt and Q are the transverse momentum and invariant mass of the lepton pair. Accordingly, the Lam-Tung relation will be violated at this momentum region, and its violation depends on the twist-three functions. However, at large transverse momentum qt~;;Q, the Lam-Tung relation still holds because all corrections are power suppressed by Lambda2/qt2 ~;; Lambda2/Q2 where Lambda is the typical nonperturbative scale.
Date: January 22, 2009
Creator: Zhou, Jian; Yuan, Feng & Liang, Zuo-Tang
Partner: UNT Libraries Government Documents Department

Single Spin Asymmetry in Inclusive Hadron Production in pp Scattering from Collins Mechanism

Description: We study the Collins mechanism contribution to the single transverse spin asymmetry in inclusive hadron production in pp scattering p{up_arrow}p {yields} {pi}X from the leading jet fragmentation. The azimuthal asymmetric distribution of hadron in the jet leads to a single spin asymmetry for the produced hadron in the Lab frame. The effect is evaluated in a transverse momentum dependent model that takes into account the transverse momentum dependence in the fragmentation process. We find the asymmetry is comparable in size to the experimental observation at RHIC at {radical}s = 200GeV.
Date: April 14, 2008
Creator: Yuan, Feng & Yuan, Feng
Partner: UNT Libraries Government Documents Department

Alignment strategy for the ATLAS tracker

Description: The ATLAS experiment is a multi-purpose particle detector that will study high-energy particle collisions produced by the Large Hadron Collider. For the reconstruction of charged particles, and their production and their decay vertices, ATLAS is equipped with a sophisticated tracking system, unprecedented in size and complexity. Full exploitation of both the Inner Detector and the muon spectrometer requires an accurate alignment. The challenge of aligning the ATLAS tracking devices is discussed, and the ATLAS alignment strategy is presented and illustrated with both data and Monte Carlo results.
Date: September 23, 2007
Creator: ATLAS & Golling, T.
Partner: UNT Libraries Government Documents Department

A Survey of Hadron Therapy Accelerator Technologies.

Description: Hadron therapy has entered a new age [1]. The number of facilities grows steadily, and 'consumer' interest is high. Some groups are working on new accelerator technology, while others optimize existing designs by reducing capital and operating costs, and improving performance. This paper surveys the current requirements and directions in accelerator technology for hadron therapy.
Date: June 25, 2007
Partner: UNT Libraries Government Documents Department

Electron-Cloud Build-Up Simulations for the FNAL Main Injector

Description: We present a summary on ongoing simulation results for the electron-cloud (EC) buildup in the context of the proposed FNAL Main Injector (MI) intensity upgrade effort [1]. Most of the results presented here are for the field-free region at the location of the retarding field analyzer (RFA) electron detector [2-4]. The primary input variable we exercise is the peak secondary electron yield (SEY) {delta}{sub max}, which we let vary in the range 1.2 {le} {delta}{sub max} {le} 1.7. By combining our simulated results for the electron flux at the vacuum chamber wall with the corresponding RFA measurements we infer that 1.25 {approx}< {delta}{sub max} {approx}< 1.35 at this location. From this piece of information we estimate features of the EC distribution for various fill patterns, including the average electron number density n{sub e}. We then compare the behavior of the EC for a hypothetical RF frequency f{sub RF} = 212 MHz with the current 53 MHz for a given total beam population N{sub tot}. The density n{sub e} goes through a clear threshold as a function of N{sub tot} in a field-free region. As expected, the higher frequency leads to a weaker EC effect: the threshold in N{sub tot} is a factor {approx} 2 higher for f{sub RF} = 212 MHz than for 53 MHz, and ne is correspondingly lower by a factor {approx} 2 when N{sub tot} is above threshold. We briefly describe further work that needs to be carried out, sensitivities in the calculation, and puzzles in the results that remain to be addressed.
Date: August 25, 2008
Creator: Furman, Miguel .A.
Partner: UNT Libraries Government Documents Department

Nb3Sn Quadrupole Magnets for the LHC IR

Description: The development of insertion quadrupoles with 205 T/m gradient and 90 mm bore represents a promising strategy to achieve the ultimate luminosity goal of 2.5 x 10{sup 34} cm{sup -2}s{sup -1} at the Large Hadron Collider (LHC). At present, Nb{sub 3}Sn is the only practical conductor which can meet these requirements. Since Nb{sub 3}Sn is brittle, and considerably more strain sensitive than NbTi, the design concepts and fabrication techniques developed for NbTi magnets need to be modified appropriately. In addition, IR magnets must provide high field quality and operate reliably under severe radiation loads. The results of conceptual design studies addressing these issues are presented.
Date: August 1, 2001
Creator: Sabbi, G.; Caspi, S.; Chiesa, L.; Coccoli, M.; Dietderich, D.r.; Ferracin, P. et al.
Partner: UNT Libraries Government Documents Department

Common Coil Magnet System for VLHC

Description: This paper introduces the common coil magnet system for the proposed very large hadron collider (VLHC). In this system, the high energy booster (HEB), the injector to VLHC, is integrated as the iron dominated low field aperture within the coldmass of the common coil magnet design introduced earlier. This 4-in-1 magnet concept for a 2-in-1 machine should provide a major cost reduction in building and operating VLHC. Moreover, the proposed design reduces the field quality problems associated with the large persistent currents in Nb{sub 3}Sn magnets. The paper also shows that the geometric field harmonics can be made small. In this preliminary magnetic design. the current dependence in harmonics is significant but not umnanageable.
Date: February 12, 1999
Creator: Gupta, R.
Partner: UNT Libraries Government Documents Department

Status of Proof-of-principle Experiment for Coherent Electron Cooling

Description: Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron colliders. To verify the concept we conduct proof-of-the-principle experiment at RHIC. In this paper, we describe the current experimental setup to be installed into 2 o'clock RHIC interaction regions. We present current design, status of equipment acquisition and estimates for the expected beam parameters.
Date: July 1, 2012
Creator: Pinayev, I.; Ben-Zvi, I.; Bengtsson, J.; Elizarov, A.; Fedotov, A. V.; Gassner, D. M. et al.
Partner: UNT Libraries Government Documents Department

Hadron Spectroscopy

Description: This review summarizes contributions to the Parallel Workshop Session on Hadron Spectroscopy at the PANIC XII conference.
Date: January 1, 1990
Creator: Isgur, Nathan
Partner: UNT Libraries Government Documents Department

Hadron Spectroscopy and Structure

Description: In this talk I review and comment upon recent developments in hadron spectroscopy and structure. The talk is organized into three main sections dealing with heavy quarkonia (QQ(bar)), hadrons containing a single heavy quark (Qq(bar) and Qqq), and hadrons containing only light quarks and glue, although I will emphasize a surprising unity of the phenomena characterizing these systems.
Date: August 1, 1992
Creator: Isgur, Nathan
Partner: UNT Libraries Government Documents Department

Energy and system size dependence of phi meson production in Cu+Cu and Au+Au collisions

Description: We study the beam-energy and system-size dependence of {phi} meson production (using the hadronic decay mode {phi} {yields} K{sup +}K{sup -}) by comparing the new results from Cu + Cu collisions and previously reported Au + Au collisions at {radical}s{sub NN} = 62.4 and 200 GeV measured in the STAR experiment at RHIC. Data presented are from midrapidity (|y| < 0.5) for 0.4 < p{sub T} < 5 GeV/c. At a given beam energy, the transverse momentum distributions for {phi} mesons are observed to be similar in yield and shape for Cu + Cu and Au + Au colliding systems with similar average numbers of participating nucleons. The {phi} meson yields in nucleus-nucleus collisions, normalized by the average number of participating nucleons, are found to be enhanced relative to those from p + p collisions with a different trend compared to strange baryons. The enhancement for {phi} mesons is observed to be higher at {radical}s{sub NN} = 200 GeV compared to 62.4 GeV. These observations for the produced {phi}(s{bar s}) mesons clearly suggest that, at these collision energies, the source of enhancement of strange hadrons is related to the formation of a dense partonic medium in high energy nucleus-nucleus collisions and cannot be alone due to canonical suppression of their production in smaller systems.
Date: October 28, 2008
Creator: Coll, STAR
Partner: UNT Libraries Government Documents Department

Indications of Conical Emission of Charged Hadrons at the BNL Relativistic HeavyIon Collider

Description: Three-particle azimuthal correlation measurements with a high transverse momentum trigger particle are reported for pp, d + Au, and Au + Au collisions at {radical}s{sub NN} = 200 GeV by the STAR experiment. Dijet structures are observed in pp, d + Au and peripheral Au + Au collisions. An additional structure is observed in central Au + Au data, signaling conical emission of correlated charged hadrons. The conical emission angle is found to be {theta} = 1.37 {+-} 0.02(stat){sub -0.07}{sup +0.06}(syst), independent of p{sub {perpendicular}}.
Date: February 9, 2009
Creator: Coll, STAR
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