DOUBLE SPIN ASYMMETRY ALT IN THE PRODUCTION OF PHOTONS, HADRONS, AND JETS

2012 ◽  
Vol 20 ◽  
pp. 29-36
Author(s):  
DANIEL PITONYAK
Keyword(s):  
Spin Asymmetry ◽  
Pp Collisions ◽  
Proton Proton ◽  
Spin Asymmetries ◽  
Double Spin Asymmetry ◽  
Single Spin ◽  
Double Spin ◽  
Single Spin Asymmetries ◽  
Complete Set ◽  
First Time

We calculate the double spin asymmetry (DSA) ALT in proton-proton (pp) collisions for the production of photons, hadrons, and jets in the collinear twist-3 framework. These processes allows us for the first time to access a complete set of collinear twist-3 functions. We also give numerical estimates for the asymmetries of which photon production shows the most promise of a measurable effect. Furthermore, we comment on how these asymmetries would allow us to probe the gluon helicity down to as of yet unexplored x values, remark on the importance of these effects in determining the evolution of the Efremov-Teryaev-Qiu-Sterman (ETQS) function TF(x, x), and discuss their usefulness in resolving the true mechanism behind the large transverse single spin asymmetries (SSAs) measured in pp collisions.

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.

scholarly journals Transverse Single-Spin Asymmetries in Proton-Proton Collisions at the AFTER@LHC Experiment in a TMD Factorisation Scheme

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
M. Anselmino ◽  
U. D’Alesio ◽  
S. Melis
Keyword(s):  
Spin Asymmetry ◽  
Parton Model ◽  
Fixed Target ◽  
Proton Proton ◽  
Spin Asymmetries ◽  
Proton Collisions ◽  
Single Spin ◽  
Single Spin Asymmetries ◽  
Target Experiment ◽  
Proton Proton Collisions

The inclusive large-pTproduction of a single pion, jet or direct photon, and Drell-Yan processes, are considered for proton-proton collisions in the kinematical range expected for the fixed-target experiment AFTER, proposed at LHC. For all these processes, predictions are given for the transverse single-spin asymmetry,AN, computed according to a Generalised Parton Model previously discussed in the literature and based on TMD factorisation. Comparisons with the results of a collinear twist-3 approach, recently presented, are made and discussed.

scholarly journals Transverse spin observables in hard-scattering hadronic processes within collinear factorization

2016 ◽  
Vol 31 (32) ◽  
pp. 1630049 ◽  
Author(s):  
Daniel Pitonyak
Keyword(s):  
Transverse Spin ◽  
Final States ◽  
Collinear Factorization ◽  
Future Directions ◽  
Proton Proton ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Double Spin ◽  
Single Spin Asymmetries ◽  
Transverse Spin Structure

We review what is currently known about the transverse spin structure of hadrons, in particular from observables that can be analyzed within a collinear framework. These effects have been around for 40 years and represent a critical test of perturbative QCD. We look at both proton–proton and lepton–nucleon collisions for various final states. While the main focus is on transverse single-spin asymmetries, we also discuss how longitudinal-transverse double-spin asymmetries offer a complimentary, yet equally important, source of information on the quark–gluon content of hadrons. We also summarize some recent progress in solidifying the theoretical formalism behind these observables and give an outlook on future directions of research.

scholarly journals Measurement of Longitudinal Spin Asymmetries for Weak Boson Production in Polarized Proton-Proton Collisions at STAR

2016 ◽  
Vol 40 ◽  
pp. 1660019
Author(s):  
Jinlong Zhang
Keyword(s):  
Spin Asymmetry ◽  
Data Set ◽  
Proton Proton ◽  
Weak Boson ◽  
Spin Asymmetries ◽  
Proton Collisions ◽  
Double Spin ◽  
Polarized Proton ◽  
The Status ◽  
Proton Proton Collisions

The production of [Formula: see text] bosons in longitudinally polarized [Formula: see text] collisions is a powerful tool to study the spin-flavor structure of the proton. We report measurements of single- and double-spin asymmetries for [Formula: see text] and [Formula: see text] production in longitudinally polarized proton-proton collisions at [Formula: see text] GeV at RHIC. The single-spin asymmetry results for [Formula: see text] from data sets collected by STAR experiment in 2011 and 2012 provided new constraints on proton’s polarized sea quark distributions and prefer a sizable value for [Formula: see text] polarization. The status for the analysis of a much larger data set collected by STAR in 2013 will also be given.

WHAT CAUSES TRANSVERSE SINGLE-SPIN ASYMMETRIES IN LEPTON-NUCLEON AND IN NUCLEON-NUCLEON SCATTERING?

2014 ◽  
Vol 25 ◽  
pp. 1460011
Author(s):  
ANDREAS METZ ◽  
DANIEL PITONYAK ◽  
ANDREAS SCHÄFER ◽  
MARC SCHLEGEL ◽  
WERNER VOGELSANG ◽  
...  
Keyword(s):  
Nucleon Nucleon ◽  
Nucleon Scattering ◽  
Transverse Momentum Dependent ◽  
Spin Asymmetries ◽  
Hadronic Physics ◽  
Single Spin ◽  
Single Spin Asymmetries ◽  
Sivers Function ◽  
First Time ◽  
Shed Light

Transverse single-spin asymmetries are among the most intriguing observables in hadronic physics. Though such asymmetries were already measured for the first time about four decades ago, their origin is still under debate. Here we consider transverse single-spin asymmetries in semi-inclusive lepton-nucleon scattering, in nucleon-nucleon scattering, and in inclusive lepton-nucleon scattering. It is argued that the single-spin asymmetries for those three processes may be simultaneously described in perturbative QCD, where the re-scattering of the active partons plays a crucial role. A comparison of single-spin asymmetries in different reactions can also shed light on the universality of transverse momentum dependent parton correlation functions. In particular, we discuss what existing data tells us about the predicted process dependence of the Sivers function.

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