Measurement of the elliptic anisotropy of charged particles produced in PbPb collisions atsNN=2.76TeV

Abstract

The anisotropy of the azimuthal distributions of charged particles produced in √ s NN = 2.76 TeV PbPb collisions is studied with the CMS experiment at the LHC. The elliptic anisotropy parameter, v 2 , defined as the second coefficient in a Fourier expansion of the particle invariant yields, is extracted using the event-plane method, two-and four-particle cumulants, and Lee-Yang zeros. The anisotropy is presented as a function of transverse momentum (p T ), pseudorapidity (η) over a broad kinematic range, 0.3 < p T < 20 GeV/c, |η| < 2.4, and in 12 classes of collision centrality from 0 to 80%. The results are compared to those obtained at lower center-of-mass energies, and various scaling behaviors are examined. When scaled by the geometric eccentricity of the collision zone, the elliptic anisotropy is found to obey a universal scaling with the transverse particle density for different collision systems and center-of-mass energies.

Exceptional thermodynamics: the equation of state of G2 gauge theory

“…These findings are derived from the observation of elliptic flow [12][13][14][15][16], electromagnetic spectra [17,18], quarkonium melting [19][20][21][22][23][24][25][26], enhanced strangeness production [27][28][29][30][31][32] and jet quenching [33][34][35][36][37][38][39][40][41][42][43][44]; for a very recent review, see ref. [45].…”

Elliptic flow of identified hadrons in Pb-Pb collisions at s N N = 2.76 $$ \sqrt{s_{\mathrm{NN}}}=2.76 $$ TeV

“…The existence of the QGP has been stipulated by observations at the Relativistic Heavy Ion Collider (RHIC) [7][8][9][10]. The first experimental results from the heavy-ion program at the LHC [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] have also provided evidence of the existence of the QGP in this new energy regime.-1 - …”

Azimuthal anisotropy harmonics from long-range correlations in high multiplicity pp collisions at CMS

“…2. The results of previous publication [5,6] to-back jet correlations on the away side as there is no evidence of long-range near-side correlation being seen in these low-multiplicity events. However, for the high multiplicity events with 110 ≤ N offline trk < 150, a deviation of v 2 between particle species is observed.…”