Conveners
Nucleon helicity structure
- Fabienne Kunne (CEA saclay)
- Brian Page (Brookhaven National Lab)
- Wally Melnitchouk (Jefferson Lab)
Nucleon helicity structure
- Fabienne Kunne (CEA saclay)
- Brian Page (Brookhaven National Lab)
- Wally Melnitchouk (Jefferson Lab)
Nucleon helicity structure
- Brian Page (Brookhaven National Lab)
- Wally Melnitchouk (Jefferson Lab)
- Fabienne Kunne (CEA saclay)
Nucleon helicity structure
- Brian Page (Brookhaven National Lab)
- Fabienne Kunne (CEA saclay)
- Wally Melnitchouk (Jefferson Lab)
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Prof. Elliot Leader (Imperial College London)12/09/2018, 14:30Nucleon Helicity StructureParallel SessionsThe paper on "A spin crisis in the parton model" first appeared 28 years ago. Since then numerous publications have attempted to clarify the issue, and to show that there is really no crisis, yet papers which talk about the "proton spin crisis" continue to appear at present. We give a careful discussion of the subtleties involved and a precise statement of the proton spin sum rule, whereby...Go to contribution page
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Nobuo Sato (Jefferson Lab)12/09/2018, 14:50Nucleon Helicity StructureParallel SessionsIn this talk I will discuss the recent updates from the JAM collaboration to extract simultaneously polarized and unpolarized PDFs and fragmentation functions from the available global data.Go to contribution page
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Dr Fernanda Steffens (DESY - Zeuthen)12/09/2018, 15:10Nucleon Helicity StructureParallel SessionsWe present spin-dependent parton distribution functions calculated within lattice QCD simulations using physical values of the light quark mass. Non-perturbative renormalization is employed, and the lattice data are converted to the MS-scheme at a scale of 2 GeV. We then reconstruct the light-cone parton distribution functions using a matching procedure. We obtain a nice overlap for a...Go to contribution page
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Dr Brad Sawatzky (Jefferson Lab)12/09/2018, 15:30Nucleon Helicity StructureParallel SessionsThe last several years of Jefferson Lab's 6~GeV physics program saw a wealth of nucleon spin structure measurements run across several Halls. In particular, E06-014 (``$d_2^n$") in Hall A (polarized neutron), and E07-003 (``SANE") in Hall C (polarized proton) took advantage of significant advances in target design and new/upgraded large solid angle detector packages to run precision...Go to contribution page
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Prof. Karl Slifer (UNH)12/09/2018, 15:50Nucleon Helicity StructureParallel SessionsMoments of spin structure functions at low Q2 provide a benchmark test of chiral dynamics, and are necessary input for calculations of atomic energy levels. We will present the results from the Jefferson Lab Hall A and C spin structure experiments at low Q2 ("g2p" and "SAGDH").Go to contribution page
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Prof. Kenneth Barish (UC Riverside)12/09/2018, 16:40Nucleon Helicity StructureParallel SessionsDouble helicity asymmetries $A_{LL}$ in hadron, jet and direct photon production in $\vec{p}$+$\vec{p}$ collisions at the Relativistic Heavy Ion Collider (RHIC) are sensitive to the gluon helicity contribution to the proton's spin. Unlike hadrons and jet, direct photon production provides clean access to the polarized gluon distribution since there is no hadronization. However, the small...Go to contribution page
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Mr Taebong Moon (Yonsei University/RIKEN)12/09/2018, 17:00Nucleon Helicity StructureParallel SessionsOne of the main goals of the RHIC spin program is the determination of the gluon helicity contribution to the proton spin. This can be accessed by measuring double helicity asymmetries ($A_{LL}$) of pion production at mid-rapidity in longitudinally polarized proton collisions. The ordering of the asymmetries with the charge of the final state pions can in addition directly infer the sign of...Go to contribution page
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Christopher Dilks (Pennsylvania State University)12/09/2018, 17:20Nucleon Helicity StructureParallel SessionsThe contribution to the spin of the proton from the gluon helicity is starting to come into focus: for gluons carrying a large fraction $x$ of the proton momentum, evidence of positive gluon polarization has been observed, via measurements of the longitudinal double-spin asymmetry $A_{LL}$ for inclusive jet and dijet production. $A_{LL}$ is sensitive to the polarized gluon distribution...Go to contribution page
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Dr Ting Lin (Texas A&M University)12/09/2018, 17:40Nucleon Helicity StructureParallel SessionsOne of the primary goals of the RHIC spin program is to determine the spin-dependent gluon distribution, Δg(x), of the proton. The measurements of the 2009 longitudinal double-helicity asymmetry, $A_{LL}$, for mid-rapidity inclusive jet and π^0 production in polarized proton+proton collisions at the center-of-mass energy √s = 200 GeV place strong constraints on Δg(x). They also for the first...Go to contribution page
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Werner Vogelsang (Univ. Tuebingen)12/09/2018, 18:00Nucleon Helicity StructureParallel SessionsWe discuss the processes pp --> (jet h) X and pp --> (\gamma h) X, for which a specific hadron or photon is observed inside a fully reconstructed jet. We present NLO results for the corresponding cross sections and show that the results can be cast into simple and systematic forms based on suitable universal jet functions. We present phenomenological results for experiments at the...Go to contribution page
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Dr Polina Kravchenko (PNPI NRC Kurchatov institute)13/09/2018, 14:30Nucleon Helicity StructureParallel SessionsA comprehensive collection of results on longitudinal double-spin asymmetries is presented for charged pions and kaons produced in semi-inclusive deep-inelastic scattering of electrons and positrons on the proton and deuteron, based on the full HERMES data set. The dependence of the asymmetries on hadron transverse momentum and azimuthal angle extends the sensitivity to the flavor structure of...Go to contribution page
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Dr fabienne kunne (CEA saclay)13/09/2018, 14:50Nucleon Helicity StructureParallel SessionsFor the first time, the K-/K+ multiplicity ratio was measured in deep-inelastic scattering for kaons carrying a large fraction z of the virtual-photon energy. The data were obtained using a 160 GeV muon beam and an isoscalar 6LiD target. They cover the range 0.01 < x < 0.4, z> 0.75, Q2 > 1 (GeV/c)2, and W > 5 GeV/c2. For values of z larger than 0.8, the results contradict expectations obtained...Go to contribution page
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Qinghua Xu (Shandong University)13/09/2018, 15:10Nucleon Helicity StructureParallel SessionsThe contribution from the sea quark polarization to the nucleon spin is an important piece for complete understanding of the nucleon spin structure. The production of W bosons in longitudinally polarized p+p collisions at RHIC provides a unique probe to the sea quark polarization, through the parity-violating single-spin asymmetry, AL. At STAR, the W bosons through the W→eν channel at...Go to contribution page
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Dr Sanghwa Park (Stony Brook University)13/09/2018, 15:30Nucleon Helicity StructureParallel SessionsThe measurement of the single spin asymmetries of parity violating W boson production in longitudinally polarized proton collisions provides unique and clean access to the light sea quark helicity distributions. The W boson couples only to left-handed quarks and right-handed anti quarks, and hence one can directly relate the charge of the W with initial state quark flavors. The PHENIX...Go to contribution page
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Dr Yann Bedfer (CEA Saclay)13/09/2018, 16:40Nucleon Helicity StructureParallel SessionsThe study of the longitudinal spin structure is one of the main objectives of the COMPASS experiment at CERN. It achieves this objective via spin-dependent measurements, both inclusive and semi-inclusive. In this talk, I will first present the final results obtained by inclusive measurements, including the spin dependent structure function g1 and derivatives obtained from it. Secondly, I will...Go to contribution page
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Andrea Moretti (TS)13/09/2018, 17:20Nucleon Helicity StructureParallel SessionsOne among the several methods proposed to access the transversity function h_1^q(x) in semi-inclusive DIS is the measurement of Lambda hyperons polarization, which can be quantified by studying the angular distribution of the proton emitted in the self-analyzing Lambda -> p pi^- decay. The struck quark inherits the transverse polarization of the target with a proportionality factor given by...Go to contribution page
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Mr Qin-Tao Song (Sokendai/KEK)13/09/2018, 17:40Nucleon Helicity StructureParallel SessionsThere exist polarized structure functions b_{1-4} for the spin-one deuteron. These functions probe very different nature of hadron spin physics from the longitudinally-polarized distributions measured by g_1 for the nucleon. The twist-two structure functions b_1 and b_2 are expressed by tensor-polarized parton distribution functions (PDFs), which indicate unpolarized parton distributions in...Go to contribution page