scholarly journals Single spin asymmetries in ℓp↑→hX processes and transverse momentum dependent factorization

2014 ◽  
Vol 89 (11) ◽  
Author(s):  
M. Anselmino ◽  
M. Boglione ◽  
U. D’Alesio ◽  
S. Melis ◽  
F. Murgia ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Transverse Momentum Dependent ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Single Spin Asymmetries

scholarly journals KANE-PUMPLIN-REPKO FACTORIZATION: ITS APPLICATION TO PRECISION MEASUREMENTS OF TRANSVERSE SPIN ASYMMETRIES AND TO THE STUDY OF TMD EVOLUTION

2014 ◽  
Vol 25 ◽  
pp. 1460002 ◽  
Author(s):  
DENNIS SIVERS
Keyword(s):  
Transverse Momentum ◽  
Inelastic Scattering ◽  
Precision Measurements ◽  
Transverse Spin ◽  
Transverse Momentum Dependent ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Hadronic Structure ◽  
Single Spin Asymmetries ◽  
Fundamental Understanding

This article presents a summary of overlapping presentations by the author to the QCD Evolution 2013 Workshop (Jefferson Lab, May 6-10, 2013) and to the Opportunities for Polarized Physics at Fermilab workshop (Fermilab, May 20-22, 2013). It contains an introduction to the concept of Kane-Pumplin-Repko (KPR) factorization and describes how this concept can be used in the analysis of high precision measurements of parity-conserving transverse single-spin asymmetries. The discussion demonstrates that such measurements can not only probe directly for specific mechanisms that enhance our fundamental understanding of nonperturbative QCD dynamics but, because transverse spin asymmetries are unambiguously parameterized by a spin-directed momentum shift, 〈δkTN (x, μ2)〉 such measurements can also be used to calibrate other phenomenological applications of transverse momentum dependent distributions (TMDs) and of TMD evolution. The calibration supplied by these measurements can thus enable the use of TMD factorization for the exploration of a broad range of other aspects of hadronic structure. KPR factorization ensures that 〈δkTN (x, μ2)〉 remains invariant under TMD evolution and this invariance can be used in the precision comparison of transverse single-spin asymmetries in the Drell-Yan process with those in Semi-inclusive deep inelastic scattering.

Transverse Single-Spin Asymmetries in Proton-Proton Collisions Within Collinear Factorization

2015 ◽  
Vol 37 ◽  
pp. 1560033
Author(s):  
Daniel Pitonyak ◽  
Koichi Kanazawa ◽  
Yuji Koike ◽  
Andreas Metz
Keyword(s):  
Transverse Momentum ◽  
Heavy Ion ◽  
High Transverse Momentum ◽  
Relativistic Heavy Ion Collider ◽  
Collinear Factorization ◽  
Transverse Momentum Dependent ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Single Spin Asymmetries ◽  
Azimuthal Asymmetries

We provide a new analysis within collinear factorization of transverse single-spin asymmetries (TSSAs) in high transverse momentum charged and neutral pion production in pp collisions at the Relativistic Heavy Ion Collider (RHIC). This study incorporates the so-called twist-3 fragmentation term and shows that one can describe RHIC data through this mechanism. Moreover, by fixing other non-perturbative inputs through extractions of transverse momentum dependent functions in e+e- → h1h2X and semi-inclusive deep-inelastic scattering (SIDIS), we provide for the first time a consistency between certain spin/azimuthal asymmetries in all three reactions (i.e., pp, e+e-, and SIDIS).

Predictions on the Transverse Single-Spin Asymmetries at Subleading Twist of Pion Production in Semi-Inclusive DIS

2016 ◽  
Vol 40 ◽  
pp. 1660030
Author(s):  
Wenjuan Mao ◽  
Zhun Lu ◽  
Bo-Qiang Ma
Keyword(s):  
Transverse Momentum ◽  
Pion Production ◽  
Diquark Model ◽  
Transverse Momentum Dependent ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Single Spin Asymmetries ◽  
Fragmentation Functions

We estimate the single-spin asymmetries with [Formula: see text] and [Formula: see text] angular dependencies for electroproduction of pions in transversely polarized semi-inclusive DIS process. We consider the effect of the twist-3 transverse momentum dependent distributions which convoluted with twist-2 fragmentation functions. We calculate these distributions in a spectator-diquark model, and predict the corresponding single-spin asymmetries at the kinematics of HERMES, JLab and COMPASS. We find that the numerical estimates show that the asymmetries are sizable, and the T-odd twist-3 TMDs play an important role in these asymmetries.

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 Introduction to the Transverse-Momentum-Weighted Technique in the Twist-3 Collinear Factorization Approach

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Hongxi Xing ◽  
Shinsuke Yoshida
Keyword(s):  
Transverse Momentum ◽  
Leading Order ◽  
Precise Description ◽  
Collinear Factorization ◽  
Factorization Approach ◽  
Hard Part ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Single Spin Asymmetries ◽  
Successful Approach

The twist-3 collinear factorization framework has drawn much attention in recent decades as a successful approach in describing the data for single spin asymmetries (SSAs). Many SSAs data have been experimentally accumulated in a variety of energies since the first measurement was done in the late 1970s and it is expected that the future experiments like Electron-Ion-Collider will provide us with more data. In order to perform a consistent and precise description of the data taken in different kinematic regimes, the scale evolution of the collinear twist-3 functions and the perturbative higher-order hard part coefficients are mandatory. In this paper, we introduce the techniques for next-to-leading order (NLO) calculation of transverse-momentum-weighted SSAs, which can be served as a useful tool to derive the QCD evolution equation for twist-3 functions and to verify the QCD collinear factorization for twist-3 observables at NLO, as well as obtain the finite NLO hard part coefficients.

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.

scholarly journals Single-Spin Asymmetries AULsinϕh in Semi-Inclusive Pions Production

2016 ◽  
Vol 40 ◽  
pp. 1660045 ◽  
Author(s):  
Zhun Lu ◽  
Wenjuan Mao
Keyword(s):  
Pion Production ◽  
Neutral Pion ◽  
Spin Asymmetry ◽  
Distribution Functions ◽  
Proton Target ◽  
Deuteron Target ◽  
Transverse Momentum Dependent ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Single Spin Asymmetries

The single-spin asymmetry [Formula: see text] of charged and neutral pion production in semi-inclusive deep-inelastic scattering on longitudinally polarized nucleon targets is studied. We particularly consider the effects of the twist-3 transverse-momentum dependent distribution functions [Formula: see text] and [Formula: see text], which are calculated in two different spectator-diquark models. We estimate the asymmetry for [Formula: see text], [Formula: see text] and [Formula: see text] produced off the proton target at HERMES and compare the results with the HERMES measurements. We also predict the same asymmetric moment for different pions at the kinematics of CLAS 5.5 GeV on a proton target, as well as at COMPASS on a deuteron target for comparison.

scholarly journals AN of Single Heavy Flavor Decay Muon in the PHENIX Experiment at RHIC

2016 ◽  
Vol 40 ◽  
pp. 1660043 ◽  
Author(s):  
Xiaorong Wang ◽  
Feng Wei
Keyword(s):  
Transverse Momentum ◽  
Spin Asymmetry ◽  
Single Spin Asymmetry ◽  
Transverse Spin ◽  
Heavy Flavor ◽  
Spin Asymmetries ◽  
Single Spin ◽  
Phenix Experiment ◽  
Single Spin Asymmetries ◽  
Heavy Flavor Production

Transverse single-spin asymmetries provide valuable information about the spin structure of the nucleon. At RHIC energies, heavy-flavor production is dominated by gluon-gluon fusion, and the subsequent decay into high [Formula: see text] electrons or muons can be observed statistically in a collider detector like PHENIX. The transverse single-spin asymmetry in heavy-flavor production originates from the initial state correlation between the internal transverse momentum of the parton and the transverse spin of the nucleon (similar with the known Sivers effect). The measurement of transverse single-spin asymmetry of single muons from heavy flavor decay at RHIC serves as a clean probe and would provide important information on the gluon Sivers function. In 2012, the PHENIX experiment collected 9.2 [Formula: see text] integrated luminosity in transversely polarized [Formula: see text] collisions at [Formula: see text] = 200 GeV with a polarization of [Formula: see text]. The signal-to-background ratio was improved by a factor of two compared to the previous RHIC 2006 and 2008 results in high transverse momentum region ([Formula: see text]GeV). The recent PHENIX preliminary results of transverse single-spin asymmetries of single heavy flavor decay muon at forward-rapidity will be shown and the possible improvement on this measurement in 2015 with the help of the FVTX detector will be discussed.

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