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Book DOUBLE TRANSVERSE SPIN ASYMMETRIES AT NLO

Download or read book DOUBLE TRANSVERSE SPIN ASYMMETRIES AT NLO written by A.STRATMANN MUKHERJEE (M.VOGELSANG, W.) and published by . This book was released on 2003 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on a next-to-leading order QCD calculation of the cross section and the spin asymmetry for isolated large-p{sub T} prompt photon production in collisions of transversely polarized protons. Corresponding measurements may be used at RHIC to determine the transversity parton distributions of the proton.

Book Longitudinal Double spin Asymmetry and Cross Section for Inclusivejet Production in Polarized Proton Collisions at Sqrt s

Download or read book Longitudinal Double spin Asymmetry and Cross Section for Inclusivejet Production in Polarized Proton Collisions at Sqrt s written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report a measurement of the longitudinal double-spinasymmetry A_LL and the differential cross section for inclusivemidrapidity jet production in polarized proton collisions at sqrt(s)=200GeV. The cross section data cover transverse momenta 5

Book Measurement of Longitudinal Double Spin Asymmetries of pi Production in P over arrow P over arrow Collisions at sqrt s

Download or read book Measurement of Longitudinal Double Spin Asymmetries of pi Production in P over arrow P over arrow Collisions at sqrt s written by Adam Philip Kocoloski and published by . This book was released on 2010 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spin dependent measurements provide incisive tests for modern theories of particle physics. The discovery that the integral of the quark helicity distribution is much too small to account for the spin of the proton is an excellent case in point. It inspired an intense period of theoretical scrutiny and a new generation of experiments to study [Delta]g, the helicity distribution of gluons in the nucleon. In particular, the unique polarized proton collider at RHIC enables a class of asymmetry measurements that are directly sensitive to gluon polarization. The STAR experiment at RHIC measures the double spin asymmetry A[subscript LL] for a variety of final states in collisions of longitudinally polarized protons in order to constrain [Delta]g. Asymmetries for mid-rapidity charged pion production benefit from large cross sections and the excellent tracking and particle identification capabilities of the STAR Time Projection Chamber. This thesis presents the first measurements of charged pion A[subscript LL] at STAR. The measurements are compared to predictions based on perturbative QCD calculations and from this comparison model-dependent constraints are placed on the integral gluon polarization [Delta]G.

Book The Double Spin Asymmetry in Exclusive Pi Electro production with CLAS

Download or read book The Double Spin Asymmetry in Exclusive Pi Electro production with CLAS written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The eg1b run was conducted using CLAS at Jefferson Lab in 2000 by the CLAS collab- oration. A 1.6 GeV - 5.6 GeV polarized electron beam and polarized nuclear targets (composed of NH3 and ND3) were used, allowing single and double spin asymmetries to be measured. This analysis deals with the double spin asymmetry A.

Book Inclusive Cross Section and Double helicity Asymmetry for math Display

Download or read book Inclusive Cross Section and Double helicity Asymmetry for math Display written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present PHENIX measurements for the cross section and double-helicity asymmetry (ALL) in inclusive [pi]0 production at midrapidity from p + p collisions at √s = 510 GeV from data taken in 2012 and 2013 at the Relativistic Heavy Ion Collider. The next-to-leading-order perturbative-quantum-chromodynamics theory calculation is in excellent agreement with the presented cross section results. The calculation utilized parton-to-pion fragmentation functions from the recent DSS14 global analysis, which prefer a smaller gluon-to-pion fragmentation function. Our [pi]0ALL results follow an increasingly positive asymmetry trend with pT and √s with respect to the predictions and are in excellent agreement with the latest global analysis results. This analysis incorporated earlier results on [pi]0 and jet ALL and suggested a positive contribution of gluon polarization to the spin of the proton [Delta]G for the gluon momentum fraction range x > 0.05. Finally, the data presented here extend to a currently unexplored region, down to x similar to 0.01, and thus provide additional constraints on the value of [Delta]G.

Book Measurement of Single and Double Spin Asymmetries in Deep Inelastic Pion Electroproduction with a Longitudinally Polarized Target

Download or read book Measurement of Single and Double Spin Asymmetries in Deep Inelastic Pion Electroproduction with a Longitudinally Polarized Target written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report the first measurement of the transverse momentum dependence of double spin asymmetries in semi-inclusive production of pions in deep inelastic scattering off the longitudinally polarized proton. Data have been obtained using a polarized electron beam of 5.7 GeV with the CLAS detector at the Thomas Jefferson National Accelerator Facility (JLab). A significant non-zero $\sin2\phi$ single spin asymmetry was also observed for the first time indicating strong spin-orbit correlations for transversely polarized quarks in the longitudinally polarized proton. The azimuthal modulations of single spin asymmetries have been measured over a wide kinematic range.

Book Precise Measurements of Beam Spin Asymmetries in Semi Inclusive pi 0 Production

Download or read book Precise Measurements of Beam Spin Asymmetries in Semi Inclusive pi 0 Production written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present studies of single-spin asymmetries for neutral pion electroproduction in semi-inclusive deep-inelastic scattering of 5.776 GeV polarized electrons from an unpolarized hydrogen target, using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. A substantial sin [Phi]h amplitude has been measured in the distribution of the cross section asymmetry as a function of the azimuthal angle [Phi]h of the produced neutral pion. The dependence of this amplitude on Bjorken x and on the pion transverse momentum is extracted with significantly higher precision than previous data and is compared to model calculations.

Book Forward Di hadron Asymmetries from P P at 8 s

Download or read book Forward Di hadron Asymmetries from P P at 8 s written by James Lucas Drachenberg and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: One unresolved question in hadronic physics is the origin of large transverse single-spin asymmetries, AN, observed in hadron production from high-energy polarized-proton collisions. Collinear perturbative Quantum Chromodynamics (pQCD) predicts that AN should scale with the quark mass, however, experiments have since reported large AN for inclusive hadron production. Recent measurements from RHIC experiments show examples of these asymmetries at forward angles in a kinematic region where pQCD cross-section calculations reasonably agree with measured cross-sections. Disentangling dynamical contributions to AN from hadro-production requires moving beyond inclusive measurements. One possibility is to investigate asymmetries in two-particle correlations due to Interference Fragmentation Functions (IFF) and the Sivers effect. In 2008, RHIC dedicated a portion of the run to transversely polarized proton collisions at sqrt(s) = 200 GeV. STAR was equipped with a Foward Meson Spectrometer (FMS) and a Forward Time Projection Chamber (FTPC), overlapping in the pseudorapidity range of 2.5 eta & lt; 4. By analyzing neutral pions with the FMS correlated with charged particles from the FTPC, correlation asymmetries can be measured at kinematics where large inclusive asymmetries have been measured. Correlations are measured for pi^0's with 2 & lt; pT, pi^0 & lt; 5 GeV/c and associated charged particles in two ranges of transverse momentum: 1 & lt; pT, ch & lt; 2 GeV/c and 0.5 & lt; pT, ch & lt; 1 GeV/c. IFF and Sivers asymmetries manifest themselves through the correlation of two particles from the same jet. These events are selected through a cut on the pair radius, delta R. Gain non-uniformities and electronics failures have resulted in large holes in trigger acceptance and associated particle acceptance, respectively. This non-uniform acceptance allows the Sivers and IFF effects to mix and distort the raw asymmetries. Techniques are developed to measure this leak-through by means of unpolarized yields and event weighting. They result in small corrections to the asymmetries. IFF and Sivers asymmetries both for xF 0 and for xF & lt; 0 are reported for forward-angle pi^0-charged particle correlations from polarized-proton collisions at sqrt(s) = 200 GeV. Asymmetries are shown corrected for full underlying-event and pileup backgrounds, as well as corrected only for pile-up contributions. It appears the asymmetries are less sensitive to delta R when corrected for the full underlying-event background. Unfortunately, statistics limitations preclude a firm conclusion.

Book Double spin Asymmetries in Diffractive Vector meson Production at HERMES

Download or read book Double spin Asymmetries in Diffractive Vector meson Production at HERMES written by Ekaterina Lipka and published by . This book was released on 2002 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: