scholarly journals Transverse single spin asymmetry ine+p↑→e+J/ψ+Xand transverse momentum dependent evolution of the Sivers function

2013 ◽  
Vol 88 (1) ◽  
Author(s):  
Rohini M. Godbole ◽  
Anuradha Misra ◽  
Asmita Mukherjee ◽  
Vaibhav S. Rawoot
2017 ◽  
Vol 32 (28n29) ◽  
pp. 1750176
Author(s):  
H. Mahdizadeh Saffar ◽  
A. Mirjalili ◽  
S. Atashbar Tehrani ◽  
M. M. Yazdanpanah

Sivers effect is describing the correlation between the transverse polarization of nucleon and the transverse momentum, [Formula: see text], of its unpolarized constituent partons. This effect is an outstanding subject and in this regard, a great deal in recent years has been considered from experimental and phenomenological points of view. It also plays an essential role to extend our understanding from nucleon structure. Semi-inclusive DIS (SIDIS) process provides us an opportunity to access to Sivers function which is dependent on transverse momentum of partons. In this paper, for the first time the covariant parton model is used to deliver us the [Formula: see text] and [Formula: see text] dependence part of Sivers function. Based on this model, this combinatory dependence is arising out from the HERAPDF parametrization group. In this paper the other required parametrized functions in Sivers function is also changed with respect to Ref. 1. The unknown parameters which exist in Sivers function can be extracted, doing a global fit over the recent available experimental data, including HERMES, COMPASS and JLAB collaborations for the single spin asymmetry (SSA) in [Formula: see text] and [Formula: see text] meson production as well as kaon production to constrain the evolved strange quark. This is done, considering advanced mathematical manipulations to overcome the difficulties which exist to compute the required multiple integrals and finally employing the CERN MINIUTE program to do a global fit. Our results for SSA are in good agreement with the available experimental data. For more confirmation a comparison between our results and the ones from Ref. 2 is also done.


2022 ◽  
Vol 258 ◽  
pp. 03002
Author(s):  
Hui Li ◽  
Xiaoyu Wang ◽  
Zhun Lu

We study the single-spin asymmetry ATsin(2ϕ−ϕS) in the pion-induced Drell-Yan process within the transverse momentum dependent factorization (TMD factorization). The asymmetry can be expressed as the convolution of the Boer-Mulders function and the transversity function. We numerically estimate the asymmetry ATsin(2ϕ−ϕS) at the COMPASS kinematics with the model results for the pion meson distributions from the light-cone wave function approach and the available parametrization for the proton distributions. We also include the TMD evolution formalism both proton and pion parton distribution functions by using two different parametrizations on nonperturbative Sudakov form factor. We find that the asymmetry ATsin(2ϕ−ϕS) as functions of xp, xπ, xF and q⊥ is qualitatively consistent with the recent COMPASS measurement.


2015 ◽  
Vol 91 (1) ◽  
Author(s):  
Rohini M. Godbole ◽  
Abhiram Kaushik ◽  
Anuradha Misra ◽  
Vaibhav S. Rawoot

2012 ◽  
Author(s):  
Vaibhav Rawoot ◽  
Rohini Godbole ◽  
Anuradha Misra ◽  
Asmita Mukherjee

2016 ◽  
Vol 40 ◽  
pp. 1660043 ◽  
Author(s):  
Xiaorong Wang ◽  
Feng Wei

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.


2015 ◽  
Vol 37 ◽  
pp. 1560069 ◽  
Author(s):  
Rohini M. Godbole ◽  
Abhiram Kaushik ◽  
Anuradha Misra ◽  
Vaibhav S. Rawoot

We estimate Sivers asymmetry in low virtuality photoproduction of J/ψ using color evaporation model and taking into account Q2- evolution of transverse momentum dependent PDF's and Sivers function. There is a substantial reduction in asymmetry as compared to our previous analysis wherein the Q2-dependence came only from DGLAP evolution of collinear part of TMDs. The estimates of asymmetry are comparable to our earlier estimates in which we had used analytical solution of only an approximated form of the evolution equations. We have also estimated asymmetry using the latest parametrization by Echevarria et al. which are based on an evolution kernel in which the perturbative part is resummed to NLL accuracy.


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