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)
Prof.
Elliot Leader
(Imperial College London)
12/09/2018, 14:30
Nucleon Helicity Structure
Parallel Sessions
The 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...
Nobuo Sato
(Jefferson Lab)
12/09/2018, 14:50
Nucleon Helicity Structure
Parallel Sessions
In 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.
Dr
Fernanda Steffens
(DESY - Zeuthen)
12/09/2018, 15:10
Nucleon Helicity Structure
Parallel Sessions
We 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...
Dr
Brad Sawatzky
(Jefferson Lab)
12/09/2018, 15:30
Nucleon Helicity Structure
Parallel Sessions
The 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...
Prof.
Karl Slifer
(UNH)
12/09/2018, 15:50
Nucleon Helicity Structure
Parallel Sessions
Moments 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").
Prof.
Kenneth Barish
(UC Riverside)
12/09/2018, 16:40
Nucleon Helicity Structure
Parallel Sessions
Double 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...
Mr
Taebong Moon
(Yonsei University/RIKEN)
12/09/2018, 17:00
Nucleon Helicity Structure
Parallel Sessions
One 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...
Christopher Dilks
(Pennsylvania State University)
12/09/2018, 17:20
Nucleon Helicity Structure
Parallel Sessions
The 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...
Dr
Ting Lin
(Texas A&M University)
12/09/2018, 17:40
Nucleon Helicity Structure
Parallel Sessions
One 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...
Werner Vogelsang
(Univ. Tuebingen)
12/09/2018, 18:00
Nucleon Helicity Structure
Parallel Sessions
We 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...
Dr
Polina Kravchenko
(PNPI NRC Kurchatov institute)
13/09/2018, 14:30
Nucleon Helicity Structure
Parallel Sessions
A 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...
Dr
fabienne kunne
(CEA saclay)
13/09/2018, 14:50
Nucleon Helicity Structure
Parallel Sessions
For 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...
Qinghua Xu
(Shandong University)
13/09/2018, 15:10
Nucleon Helicity Structure
Parallel Sessions
The 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...
Dr
Sanghwa Park
(Stony Brook University)
13/09/2018, 15:30
Nucleon Helicity Structure
Parallel Sessions
The 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...
Dr
Yann Bedfer
(CEA Saclay)
13/09/2018, 16:40
Nucleon Helicity Structure
Parallel Sessions
The 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...
Andrea Moretti
(TS)
13/09/2018, 17:20
Nucleon Helicity Structure
Parallel Sessions
One 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...
Mr
Qin-Tao Song
(Sokendai/KEK)
13/09/2018, 17:40
Nucleon Helicity Structure
Parallel Sessions
There 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...