Abstract
A sizable $\cos 4\phi$ azimuthal asymmetry in exclusive di-pion production near $\rho^0$ resonance peak in ultraperipheral heavy ion collisions recently has been reported by STAR collaboration. We show that both elliptic gluon Wigner distribution and final state soft photon radiation can give rise to this azimuthal asymmetry. The fact that the QED effect alone severely underestimates the observed asymmetry might signal the existence of the nontrivial correlation in quantum phase distribution of gluons.
Highlights
Probing the gluon tomography in photoproduction of dipionKey Laboratory of Particle Physics and Particle Irradiation (MOE), Institute of Frontier and Interdisciplinary Science, Shandong University, (QingDao), Shandong 266237, China (Received 11 July 2021; accepted 13 October 2021; published 17 November 2021)
The study of nucleon/nucleus multiple-dimensional partonic structure has been widely recognized as one of the most important frontiers of hadronic physics
Within perturbative QCD factorization framework, 3D partonic structure of nucleon is quantified by transverse momentumdependent distributions (TMDs) and generalized parton distributions (GPDs)
Summary
Key Laboratory of Particle Physics and Particle Irradiation (MOE), Institute of Frontier and Interdisciplinary Science, Shandong University, (QingDao), Shandong 266237, China (Received 11 July 2021; accepted 13 October 2021; published 17 November 2021). A sizable cos 4φ azimuthal asymmetry in exclusive dipion production near ρ0 resonance peak in ultraperipheral heavy-ion collisions recently has been reported by STAR collaboration. We show that both elliptic gluon Wigner distribution and final-state soft photon radiation can give rise to this azimuthal asymmetry. The fact that the QED effect alone severely underestimates the observed asymmetry might signal the existence of the nontrivial correlation in quantum phase distribution of gluons
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
