scholarly journals Transverse Single Spin Asymmetries of Forward π0 and Jet-like Events in s = 500 GeV Polarized Proton Collisions at STAR

2016 ◽  
Vol 40 ◽  
pp. 1660037 ◽  
Author(s):  
Yuxi Pan
Keyword(s):  
Final States ◽  
High Transverse Momentum ◽  
Initial State ◽  
Final State ◽  
Spin Asymmetries ◽  
Proton Collisions ◽  
Single Spin ◽  
Single Spin Asymmetries ◽  
Polarized Proton ◽  
State Models

The large transverse single spin asymmetries (SSA) of high [Formula: see text] inclusive hadrons produced in polarized proton collisions are usually explained by means of collinear twist-3 multi-parton correlations. In this picture these asymmetries can originate from initial-state twist-3 parton distributions in the polarized proton and/or through the coupling between proton transversity and twist-3 fragmentation functions. The measurement of SSA for forward inclusive hadrons produced in [Formula: see text] collisions out to high transverse momentum helps to examine the validity and interplay of these initial- and final-state models. These models can be further explored by investigating the dependence of the SSA on event topologies. We present our latest status on the measurement of SSA for forward inclusive [Formula: see text] detected within [Formula: see text] in [Formula: see text] = 500 GeV [Formula: see text] collisions as well as its dependence on event topologies. We will also present our analysis of Sivers and Collins asymmetries for forward jet-like events consisting of multi-photon final states. The measurements are based on the data taken in 2011 with integrated luminosity [Formula: see text] 22 [Formula: see text].

scholarly journals Azimuthal Single-Spin Asymmetries of Charged Pions in Jets in s = 200 GeV p↑p Collisions at STAR

2016 ◽  
Vol 40 ◽  
pp. 1660040 ◽  
Author(s):  
J. Kevin Adkins ◽  
James L. Drachenberg
Keyword(s):  
Spin Asymmetry ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collider ◽  
Spin Asymmetries ◽  
Proton Collisions ◽  
Single Spin ◽  
Single Spin Asymmetries ◽  
Polarized Proton ◽  
Charged Pions ◽  
200 Gev

Single spin asymmetry measurements ([Formula: see text]) of the azimuthal distribution of charged pions inside jets produced in transversely polarized proton collisions are sensitive to the transversity distribution and the Collins fragmentation function. The STAR Detector at the Relativistic Heavy Ion Collider is well suited for these types of measurements as it is capable of full jet reconstruction and charged pion identification in the mid-rapidity region ([Formula: see text][Formula: see text][Formula: see text][Formula: see text]). We report here the first observation of Collins [Formula: see text] asymmetries in [Formula: see text] GeV [Formula: see text] collisions.

scholarly journals MEASUREMENT OF FORWARD JETS AT RHIC

2014 ◽  
Vol 25 ◽  
pp. 1460022 ◽  
Author(s):  
◽  
L. C. BLAND
Keyword(s):  
Angular Momentum ◽  
Transverse Momentum ◽  
Orbital Angular Momentum ◽  
Initial State ◽  
Spin Asymmetries ◽  
Jet Production ◽  
Single Spin ◽  
Single Spin Asymmetries ◽  
Forward Jets

We present first measurements of forward jet production from p↑ + p collisions at [Formula: see text] GeV, including transverse single spin asymmetries. These asymmetries are expected to be sensitive to spin-correlated transverse momentum in the initial state, which is particularly interesting because it is related to orbital angular momentum in the proton.

scholarly journals Initial-state interactions and single-spin asymmetries in Drell–Yan processes

2002 ◽  
Vol 642 (1-2) ◽  
pp. 344-356 ◽  
Author(s):  
Stanley J. Brodsky ◽  
Dae Sung Hwang ◽  
Ivan Schmidt
Keyword(s):  
Initial State ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Single Spin Asymmetries

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.

scholarly journals Cross sections and transverse single-spin asymmetries in forward jet production from proton collisions ats=500 GeV

2015 ◽  
Vol 750 ◽  
pp. 660-665 ◽  
Author(s):  
L.C. Bland ◽  
E.J. Brash ◽  
H.J. Crawford ◽  
A.A. Derevschikov ◽  
K.A. Drees ◽  
...  
Keyword(s):  
Cross Sections ◽  
Spin Asymmetries ◽  
Proton Collisions ◽  
Jet Production ◽  
Single Spin ◽  
Single Spin Asymmetries

scholarly journals Proton Quark Helicity Structure via W-Boson Production in PP Collision @ Phenix

2016 ◽  
Vol 40 ◽  
pp. 1660018
Author(s):  
F. Giordano
Keyword(s):  
W Boson ◽  
Light Quark ◽  
Center Of Mass ◽  
Proton Spin ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Single Spin Asymmetries ◽  
Quark Spin ◽  
Polarized Proton ◽  
The Status

The spin structure of the proton has been long studied in the past decades, but, while the contributions to the proton spin from valence quarks is by now precisely known, large uncertainties are still affecting our knowledge of the sea quark contributions. The measurement of single-spin asymmetries of the parity violating W production in pp collision allows a (quasi-)model independent access to the flavor-dependent light sea quark contributions. Being maximally parity violating, the [Formula: see text] charge can be directly realted to the quark and antiquark flavor, and in addition, moving from forward to backward rapidities with respect to the polarized proton beam direction it is possible to change the relative contributions of u, d, anti-u, anti-d quarks, thus accessing each light-quark spin alignment with respect to the proton spin. At PHENIX, the W boson produced in pp collision at center of mass energies of about 500 GeV is accessed via its decays into electron (muon) at central (forward) rapidities. Here the status of the analysis and the most updated results is reported.

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