CGC/saturation approach: re-visiting the problem of odd harmonics in angular correlations

• Main Authors: E. Gotsman, E. Levin
• Format: Article
• Language: English
• Published: SpringerOpen 2018-09-01
• Series: European Physical Journal C: Particles and Fields
• Online Access: http://link.springer.com/article/10.1140/epjc/s10052-018-6257-3

Abstract In this paper we demonstrate that the selection of events with different multiplicities of produced particles, leads to the violation of the azimuthal angular symmetry, $$\phi \rightarrow \pi - \phi $$ ϕ→π-ϕ . We find for LHC and lower energies, that this violation can be so large for the events with multiplicities $$n \ge 2 \bar{n}$$ n≥2n¯ , where $$\bar{n}$$ n¯ is the mean multiplicity, that it leads to almost no suppression of $$v_n$$ vn , with odd n. However, this can only occur if the typical size of the dipole in DIS with a nuclear target is small, or $$Q^2 \,>\,Q^2_s\left( A; Y_{\mathrm{min}},b\right) $$ Q2>Qs2A;Ymin,b , where $$Q_s$$ Qs is the saturation momentum of the nucleus at $$Y = Y_{\mathrm{min}}$$ Y=Ymin . In the case of large sizes of dipoles, when $$Q^2 \,<\,Q^2_s\left( A; Y_{\mathrm{min}},b\right) $$ Q2<Qs2A;Ymin,b , we show that $$v_n =0$$ vn=0 for odd n. Hadron-nucleus scattering is discussed.