Sea quark Sivers distribution

Abstract

We compute sea quark Sivers distribution within color glass condensate(CGC) framework. It has been found that up to the leading logarithm accuracy, the collinear twist-3 approach and the CGC calculation yield the same result for sea quark Sivers distribution in the dilute limit. We further verify that transverse momentum dependent factorization is consistent with CGC treatment at small x for the case of transverse spin asymmetry in open charm quark production in semi-inclusive deeply inelastic scattering process in an overlap kinematical region.PACS numbers: I. INTRODUCTIONPolarization dependent phenomenology at small x has attracted a lot of attentions in recent years, as it plays an important role in studying gluon tomography of nucleon/nuclei. Employing powerful color glass condensate(CGC) effective theory [1] and transverse momentum dependent(TMD) factorization [2,3] to polarization effects at small x has produced fruitful results. Among various topical issues in small x spin physics, small x parton helicity distributions [4,5], linearly polarization of small x gluons [6][7][8][9][10][11][12][13][14], (for a recent review covering this topic, see [15]), spin independent odderon [16][17][18] and spin dependent odderon [19][20][21], and elliptical gluon distribution [22][23][24][25][26] were most extensively investigated recently. In this paper, we further explore the phenomenological consequence of spin dependent odderon.In perturbative QCD, odderon is a color-singlet exchange and can be formed by three gluons in a symmetric color state. In the saturation regime, the expectation value of odderon that incorporates multiple gluon exchange effect has been computed in the MV model [1] with a cubic term [27]. The energy dependence of the odderon exchange is described by the BKP equation [28], which also can be formulated in the dipole model [29] and CGC framework [30,31]. It was found in Ref.[19] that a spin dependent odderon can be induced by an asymmetric color source distribution (i.e. valence quark distribution in the context of the MV model) in the transverse plane of a transversely polarized nucleon [32][33][34]. To be more precise, transverse momentum transferred through spin dependent odderon is correlated with transverse spin of target. In a more recent work [20], three T-odd gluon TMDs are shown to be identical and related to the spin dependent odderon. It turns out that the spin dependent odderon is the only possible source contributing to transverse single spin asymmetries(SSAs) at small x in the context of TMD factorization and CGC framework.During the past few decades, transverse single spin asymmetries in high energy scattering is one of the major focus in hadron physics studies. It not only poses the great theoretical challenge to account for the observed large SSAs, but also offers us opportunities to address some central aspects of hadron physics, such as the universality issue associated with QCD factorization theorem, and parton orbital angular momentum inside nucleon. Depending on kinematical r...

Quark sivers function at small x: spin-dependent odderon and the sub-eikonal evolution

“…Similar conclusion of the odderon dominance in the small-x quark Sivers function was reached in [3] using the expression for the small-x unpolarized quark TMD (unintegrated quark distribution) from [94,99] (see also [23,100]). While qualitatively our result and that in [3] agree on the odderon-driven quark Sivers TMD, a more detailed comparison between the two calculations is left for future work. The importance of C-odd correlators in the Sivers asymmetry was also pointed out in [101,102].…”

“…Indeed, in [5] the odderon was shown to generate single transverse spin asymmetry for the quark jet production in scattering of a quark on a transversely polarized nucleon, further suggesting the odderon's connection with the quark Sivers function. Moreover, recently, in [3] it was shown that the spin-dependent odderon does contribute to the quark Sivers function. In this work we study the intersection of these diverse areas of QCD by constructing the small-x asymptotics of the quark Sivers function.…”

“…In this work we study the intersection of these diverse areas of QCD by constructing the small-x asymptotics of the quark Sivers function. Our approach is different from [3,4] since we do not limit our analysis to the eikonal contribution and study the sub-eikonal corrections to the quark Sivers function as well.…”

Electron-ion collider in China

“…2.8. Recent theoretical study suggested an opposite sign between the strange quark and anti-strange quark Sivers functions [82] apart from the sign-flip prediction of the Sivers functions probed in SIDIS and Drell-Yan processes. The experimental test of this prediction at EicC will enrich our knowledge about the proton spin structure, particularly in the relatively small x region.…”

Spin-dependent Pomeron and Odderon in elastic proton–proton scattering

“…Yet, the exact treatment of the problem has been difficult due to the lack of a systematic way to connect the Pomeron and Odderon with the spin degrees of freedom of the scattering (composite) particles such as protons in QCD. 1 Recently, however, there has been a significant progress in our understanding of the interplay between the Odderon and the proton spin [29][30][31][32][33][34]. In the Deep Inelastic Scattering (DIS) at small-x, the Color Glass Condensate (CGC) framework [35] provides a consistent description of the Pomeron and Odderon in terms of Wilson line correlators.…”