A first unbiased global determination of polarized PDFs and their uncertainties

Abstract

We present a first global determination of spin-dependent parton distribution functions (PDFs) and their uncertainties using the NNPDF methodology: NNPDFpol1.1. Longitudinally polarized deep- inelastic scattering data, already used for the previous NNPDFpol1.0 PDF set, are supplemented with the most recent polarized hadron collider data for inclusive jet and W boson production from the STAR and PHENIX experiments at RHIC, and with open-charm production data from the COMPASS experiment, thereby allowing for a separate determination of the polarized quark and anti-quark PDFs, and an improved determination of the medium- and large-x polarized gluon PDF. We study the phe- nomenological implications of the NNPDFpol1.1 set, and we provide predictions for the longitudinal double-spin asymmetry for semi-inclusive pion production at RHIC

Review on Recent Results from RHIC Polarized Collider; Unexpected Forward Neutron Asymmetry

“…5 are inclusive π 0 and jet measurements by PHENIX and STAR experiments, respectively. The polarized gluon distribution function ∆g(x, Q 2 ) is extracted by fitting data based on a next-to-leading order (NLO) pQCD framework [17] [18]. These global fitting models are confirmed to reproduce inclusive cross sections.…”

“…The experimental efforts to extend the measured region to lower x region where the majority of gluon exists is now underway. x T for π 0 production at mid-rapidity with the point-to-point uncertainties in 200 GeV (blue circles) [13] and 510 GeV (red squares) [14] p+p collisions, compared to NLO predictions for three recent NLO global analyses [17][18][19] (blue curves for 200 GeV and red curves for 510 GeV). The gray/gold bands give the correlated systematic uncertainties.…”

“…for inclusive π 0 measured in PHENIX at √ s = 510 GeV. (right) A LL vs. x T for inclusive jet production at mid-rapidity in 200 GeV (blue circles) [6] and 510 GeV (red squares) [16] p+p collisions, compared to NLO predictions for three recent NLO global analyses [17][18][19] (blue curves for 200 GeV and red curves for 510 GeV).…”

Target mass corrections and higher twist effects in polarized deep-inelastic scattering

“…In Table VIII, we present the values for the first moments of the polarized quark and gluon extracted from our model at Q 2 0 = 4 GeV 2 . They are compared with recent fit results of DSSV08 [10] (DIS, SIDIS, and RHIC), BB10 [11] (DIS data), LSS10 [9] (DIS and SIDIS data), AAC08-Set A [12] (DIS), and NFRR12 [84] (DIS data). The values of ∆Σ are almost comparable, while different ∆g are reported.…”

Polarized parton densities and spin dependent structure function of the nucleon

“…We have different analysis to determine PPDFs parametrization such as simple polynomials approach, neural networks for PPDFs parametrization and etc such as DSSV [2][3][4], NNPDF [5,6] [7].…”