Beam-target double spin asymmetries in the reaction γ→d→→πNN near threshold with final-state rescattering effects

2020 ◽  
Vol 420 ◽  
pp. 168254 ◽  
Author(s):  
E.M. Darwish ◽  
M.M. Almarashi ◽  
M. Saleh Yousef
Keyword(s):  
Final State ◽  
Spin Asymmetries ◽  
Double Spin ◽  
Near Threshold

Influence of final-state interaction on double spin asymmetries in incoherent π+-photoproduction on the deuteron near threshold

2020 ◽  
Vol 29 (08) ◽  
pp. 2050056
Author(s):  
E. M. Darwish ◽  
H. M. Al-Ghamdi
Keyword(s):  
Cross Sections ◽  
Energy Region ◽  
Final State Interaction ◽  
Reaction Model ◽  
Final State ◽  
Total Cross Sections ◽  
Spin Asymmetries ◽  
Double Spin ◽  
Final State Interactions ◽  
Near Threshold

Incoherent [Formula: see text]-photoproduction on the deuteron is investigated for photon energies near threshold with particular focus on beam-target double spin asymmetries. The analysis is based on a [Formula: see text] reaction model in which realistic elementary amplitudes for [Formula: see text], [Formula: see text] and [Formula: see text] are incorporated. Numerical results on all possible beam-target double spin asymmetries of the differential and total cross-sections in the photon energy region near threshold are presented. Effects of [Formula: see text] and [Formula: see text] final-state interactions are investigated and their roles are found to be important.

scholarly journals Longitudinal Double Spin Asymmetries of π0 - Jet Correlations in Polarized Proton Collisions at s = 510 GeV at STAR

2018 ◽  
Vol 46 ◽  
pp. 1860011
Author(s):  
Yaping Wang
Keyword(s):  
Spin Asymmetry ◽  
Distribution Functions ◽  
Parton Distribution Functions ◽  
Final State ◽  
Model Calculations ◽  
Spin Asymmetries ◽  
Proton Collisions ◽  
Rapidity Region ◽  
Double Spin ◽  
Polarized Proton

One of the primary goals of the spin physics program at STAR is to constrain the polarized gluon distribution function, [Formula: see text], by measuring the longitudinal double-spin asymmetry ([Formula: see text]) of various final-state channels. Using a jet in the mid-rapidity region [Formula: see text] correlated with an azimuthally back-to-back [Formula: see text] in the forward rapidity region [Formula: see text] provides a new possibility to access the [Formula: see text] distribution at Bjorken-[Formula: see text] down to 0.01. Compared to inclusive jet or inclusive [Formula: see text] measurements, this channel also allows to constrain the initial parton kinematics. In these proceedings, we will present the status of the analysis of the [Formula: see text]-jet [Formula: see text] in longitudinally polarized proton+proton collisions at [Formula: see text] =510 GeV with 80 pb[Formula: see text] of data taken during the 2012 RHIC run. We also compare the projected [Formula: see text] uncertainties to theoretical predictions of the [Formula: see text] by next-to-leading order (NLO) model calculations with different polarized parton distribution functions.

MEASUREMENT OF POLARIZED QUARK DISTRIBUTIONS AT HERMES

2003 ◽  
Vol 18 (08) ◽  
pp. 1185-1192
Author(s):  
◽  
STEFAN BERNREUTHER
Keyword(s):  
Cross Section ◽  
Kinematic Range ◽  
Spin Asymmetries ◽  
Double Spin ◽  
Hermes Experiment ◽  
Down Quark ◽  
Up Quark ◽  
Rich Detector ◽  
The Individual ◽  
Quark Flavors

The HERMES experiment has measured double spin asymmetries in the cross section for deep–inelastic scattering of longitudinally polarized positrons on longitudinally polarized 3 He (1995), 1 H (1996/97), and 2 D (1998) targets. A kinematic range of 0.023 < x < 0.6, and 1 GeV 2 < Q2 < 15 GeV 2 has been covered. From these asymmetries, based on inclusive and semi–inclusive measurements, polarized quark distributions are extracted as a function of x for up [Formula: see text] and down [Formula: see text] flavors as well as for valence and sea quarks. In the measured range, the up quark polarization is positive while the down quark polarization is negative. The sea quark polarization is compatible with zero. In this analysis all sea quark polarizations have been assumed to be flavor symmetric. Presently HERMES is analyzing a high statistics 2 D data sample taken in 1999-2000. For these data it is possible to identify pions and kaons with a RICH detector which was installed in 1998. This will enable an extraction of the individual sea quark flavors [Formula: see text], [Formula: see text], and [Formula: see text] without any symmetry assumptions.

scholarly journals Double spin asymmetries through QCD instantons

2014 ◽  
Vol 90 (11) ◽  
Author(s):  
Yachao Qian ◽  
Ismail Zahed
Keyword(s):  
Spin Asymmetries ◽  
Double Spin

scholarly journals STUDY OF THE η-7Be INTERACTION NEAR THRESHOLD IN p-6Li FUSION

2009 ◽  
Vol 18 (05n06) ◽  
pp. 1383-1388
Author(s):  
N. J. UPADHYAY ◽  
N. G. KELKAR ◽  
K. P. KHEMCHANDANI ◽  
B. K. JAIN
Keyword(s):  
Wave Function ◽  
Final State Interaction ◽  
Radial Wave Function ◽  
State Interaction ◽  
Nuclear Medium ◽  
Final State ◽  
Radial Wave ◽  
Near Threshold

We present a calculation for η production in the p-6Li fusion near threshold including the η-7Be final state interaction (FSI). We consider the 6Li and 7Be nuclei as α-d and α-3He clusters respectively. The calculations are done for the lowest states of 7 Be with [Formula: see text] resulting from the L = 1 radial wave function. The η-7Be interaction is incorporated through the η-7BeT–matrix, constructed from the medium modified matrices for the η-3He and η-α systems. These medium modified matrices are obtained by solving few body equations, where the scattering in nuclear medium is taken into account.

scholarly journals Target and double spin asymmetries of deeply virtual π0 production with a longitudinally polarized proton target and CLAS

2017 ◽  
Vol 768 ◽  
pp. 168-173 ◽  
Author(s):  
A. Kim ◽  
H. Avakian ◽  
V. Burkert ◽  
K. Joo ◽  
W. Kim ◽  
...  
Keyword(s):  
Proton Target ◽  
Spin Asymmetries ◽  
Double Spin ◽  
Polarized Proton ◽  
Polarized Proton Target
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