scholarly journals Azimuthal transverse single-spin asymmetries of inclusive jets and charged pions within jets from polarized-proton collisions at s=500  GeV

2018 ◽  
Vol 97 (3) ◽  
Author(s):  
L. Adamczyk ◽  
J. R. Adams ◽  
J. K. Adkins ◽  
G. Agakishiev ◽  
M. M. Aggarwal ◽  
...  
Keyword(s):  
Spin Asymmetries ◽  
Proton Collisions ◽  
Single Spin ◽  
Inclusive Jets ◽  
Single Spin Asymmetries ◽  
Polarized Proton ◽  
Charged Pions

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 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 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.

scholarly journals SPIN PHYSICS WITH STAR

2003 ◽  
Vol 18 (08) ◽  
pp. 1335-1342 ◽  
Author(s):  
◽  
JOANNA KIRYLUK
Keyword(s):  
Star Collaboration ◽  
Gluon Polarization ◽  
Proton Proton ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Double Spin ◽  
Single Spin Asymmetries ◽  
Polarized Proton ◽  
First Time ◽  
Proton Proton Collisions

The STAR collaboration aims to study polarized proton-proton collisions at RHIC. The emphasis of the spin run this year is on transverse single spin asymmetries. Beyond 2001, we aim to determine directly and precisely the gluon polarization, as well as the polarizations of the u, [Formula: see text], d and [Formula: see text] quarks in the proton by measuring in addition longitudinal and double spin asymmetries. Furthermore, we aim to measure for the first time the quark transversity distributions. These measurements will improve substantially the knowledge and understanding of the spin structure of the nucleon.

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