Elliptic flow in small systems due to elliptic gluon distributions?

Hagiwara, Yoshikazu; Hatta, Yoshitaka; Xiao, Bo-Wen; Yuan, Feng

doi:10.1016/j.physletb.2017.05.083

Cited by 32 publications

(33 citation statements)

References 44 publications

(74 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As for the cos 2φ term, it is essential to consider the elliptic gluon Wigner distribution [17][18][19] which represents the dominant angular dependence of the dipole S-matrix. In this regard, it is interesting to note that the elliptic gluon distribution has been recently proposed [20] as a possible underlying mechanism for the observed elliptic flow (cos 2φ azimuthal correlation among the final state hadrons) in high energy pp and pA collisions [35]. Thus the same distribution plays an important role to generate the cos 2φ distribution both in DVCS and in inclusive hadron production in pA collisions (see also [19]).…”

Section: Discussionmentioning

confidence: 97%

“…It is at most a few percent in magnitude compared to F 0 , but has very different functional dependencies on x and q ⊥ [18]. It can thus lead to distinct experimental signatures [17,19,20]. One of the main goals of this paper is to clarify the role of F ǫ in DVCS.…”

Section: The Dipole S-matrix and The Gluon Gpdmentioning

confidence: 97%

“…We have included a factor −2 to adjust to the normalization A T ∼ −2S in (20). If we change variables asq ⊥ = q ⊥ + δ ⊥ , (37) takes the form…”

Section: Momentum Space Calculation and The Collinear Limitmentioning

confidence: 99%

“…In this paper, we investigate this physics in the small-x dipole formalism, which is also known as the color-glass condensate (CGC) formalism [16]. We will show that the cos 2φ correlation in DVCS provides a unique opportunity to test the CGC prediction, and at the same time provides crucial information on the gluon tomography at small-x, in particular, that associated with the so-called elliptic gluon distribution [17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Gluon tomography from deeply virtual Compton scattering at small x

2017

Self Cite

View full text Add to dashboard Cite

We present a full evaluation of the deeply virtual Compton scattering (DVCS) cross section in the dipole framework in the small-x region. The result features the cos φ and cos 2φ azimuthal angular correlations which have been missing in previous studies based on the dipole model. In particular, the cos 2φ term is generated by the elliptic gluon Wigner distribution whose measurement at the planned electron-ion collider (EIC) provides an important information about the gluon tomography at small-x. We also show the consistency with the standard collinear factorization approach based on the quark and gluon generalized parton distributions (GPDs).

show abstract

Section: Discussionmentioning

confidence: 97%

Section: The Dipole S-matrix and The Gluon Gpdmentioning

confidence: 97%

“…We have included a factor −2 to adjust to the normalization A T ∼ −2S in (20). If we change variables asq ⊥ = q ⊥ + δ ⊥ , (37) takes the form…”

Section: Momentum Space Calculation and The Collinear Limitmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Gluon tomography from deeply virtual Compton scattering at small x

2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…[23,22]. Not long ago, it was also pointed out that gluon GTMDs can be studied in protonnucleus collisions [24]. With the exception of [21], the papers on observables for GTMDs deal with the small-x region of parton saturation.…”

Section: Introductionmentioning

confidence: 99%

Observables for Generalized TMDs of Quarks

Bhattacharya¹,

Metz²,

Zhou³

2018

Proceedings of QCD Evolution 2017 — PoS(QCDEV2017)

View full text Add to dashboard Cite

Generalized TMDs (GTMDs) of hadrons are the most general two-parton correlation functions. Upon certain projections, several GTMDs reduce to generalized parton distributions (GPDs) and transverse momentum dependent parton distributions (TMDs), respectively. Therefore, GTMDs can be considered as partonic "mother functions". Moreover, two of the GTMDs play an important role in the nucleon spin structure. We show that, by means of the exclusive double Drell-Yan process, GTMDs for quarks can in principle be measured. This is the first known process which is sensitive to these objects. Specific GTMDs can be addressed via suitable polarization observables. We also identify other processes that are directly sensitive to GTMDs.

show abstract

Directed flow from C-odd gluon correlations at small x

Boer

Daal

Mulders

et al. 2018

J. High Energ. Phys.

View full text Add to dashboard Cite

It is shown that odd harmonic azimuthal correlations, including the directed flow v 1 , in forward two-particle production in peripheral proton-nucleus (pA) collisions can arise simply from the radial nuclear profile of a large nucleus. This requires consideration of the C-odd part of the gluonic generalized transverse momentum dependent (GTMD) correlator of nucleons in the nucleus. The gluonic GTMD correlator is the Fourier transform of an off-forward hadronic matrix element containing gluonic field strength tensors that are connected by gauge links. It is parametrized in terms of various gluon GTMD distribution functions (GTMDs). We show (in a gauge invariant way) that for the relevant dipole-type gauge link structure in the small-x limit the GTMD correlator reduces to a generalized Wilson loop correlator. The Wilson loop correlator is parametrized in terms of a single function, implying that in the region of small x there is only one independent dipole-type GTMD, which can have a C-odd part. We show that the odderon Wigner distribution, which is related to this C-odd dipole GTMD by a Fourier transform, generates odd harmonics in the two-particle azimuthal correlations in peripheral pA collisions. We calculate the first odd harmonic v 1 for forward production within the color glass condensate framework in the limit of a large number of colors. We find that nonzero odd harmonics are present without breaking the rotational symmetry of the nucleus, arising just from its inhomogeneity in the radial direction. Using a CGC model with a cubic action, we illustrate that percent level v 1 can arise from this C-odd mechanism. In contrast, we show that only even harmonics arise in diffractive dijet production in ultra-peripheral pA collisions where this gluon dipole GTMD also appears.

show abstract

Elliptic flow in small systems due to elliptic gluon distributions?

Cited by 32 publications

References 44 publications

Gluon tomography from deeply virtual Compton scattering at small x

Gluon tomography from deeply virtual Compton scattering at small x

Observables for Generalized TMDs of Quarks

Directed flow from C-odd gluon correlations at small x

Contact Info

Product

Resources

About