The dense-dense IP-Glasma initial dynamics Schenke et al.
It is therefore important to quantify whether the results of Mantysaari et al. This flatter behavior is also anticipated in the CGC EFT power counting for large N c h because ρ p from the projectile is promoted to a Wilson line U in the dense-dense limit. However for v 3, they do not see the √ N c hĭependence but a much flatter behavior. ( 2017), also exhibit relative independence on N c h for v 2. Studies which include a dense-dense CGC initial state, followed by hydrodynamic evolution Mantysaari et al. It is unclear at present what the corresponding qualitative expectations are in kinetic and hydrodynamic models for p+A collisions. Remarkably, we find that the anticipated scaling of v 2, 3, 4 with N c h, obtained from the CGC power counting, is in excellent agreement with the ATLAS data. The curved vertical line denotes the cut separating the amplitude from the complex conjugate amplitude. ( 2015).įigure 1: Diagrammatic representation of the leading order contributions to the a) P-even and b) P-odd parts of the inclusive gluon production cross section the straight vertical lines represent multiple scattering in the gluon “shockwave” field of the target. For instance, numerical work in the dense-dense limit of the CGC EFT, where all orders in both ρ p / k 2 ⊥, p and ρ t / k 2 ⊥, t are kept, clearly recover finite values of v 3 Lappi et al.
This is well known to be an artifact of the leading order in ρ p / k 2 ⊥, p approximation. While this dilute-dense approximation may be sufficient to compute the even harmonics v 2 n, an accidental parity symmetry sets v 3 = 0 at this order. Here ρ p ( ρ t ) is color charge density in the proton (lead nucleus) and k ⊥, p ( k ⊥, t) is the transverse momentum of the scattered gluon from the proton (lead nucleus). ( 2004) Kovner and Lublinsky ( 2013) Kovchegov and Wertepny ( 2013) of the CGC EFT consists of keeping terms in the solution of the QCD Yang-Mills equations to compute inclusive gluon amplitudes that are to lowest order in the ratio ρ p / k 2 ⊥, p in the projectile but to all orders in the ratio ρ t / k 2 ⊥, t in the target 1 1 1A further glasma graph approximation corresponds to the regime where one expands to lowest order in both ρ p / k 2 ⊥, p and ρ t / k 2 ⊥, t Dumitru et al. The dilute-dense approximation Kovchegov and Mueller ( 1998) Dumitru and McLerran ( 2002) Blaizot et al.
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