Speaker
Sooraj Krishnan Radhakrishnan
(State University of New York (US))
Description
Detailed measurement of the Fourier harmonics ($v_n$) associated with the
azimuthal modulation of two-particle correlation structures over
$-5 < \delta\eta < 5$ in 31 nb$^{-1}$ p + Pb collisions are presented. The $v_n$
results are presented as a function of $p_T$, \eta, and event activity
characterized by the number of reconstructed tracks in $-2.5 < \eta < 2.5$,
and the total transverse energy on the Pb-going side ($3.2 < \eta < 4.9$).
The elliptic, triangular, and quadrangular coefficients, $v_2$, $v_3$ and
$v_4$, are extracted for $0.5 < p_T < 15$ GeV, significantly extending the
previous measurements. The v_n values are found to reach a maximum
around 3-5 GeV and then decrease to a finite positive values at $p_T > 10$
GeV, similar to the behavior seen in Pb+Pb collisions. Evidence for
rapidity-even dipolar flow $v_1$ is also observed, further supporting a
collective origin of the long-range two-particle correlations. The first
measurement of the eta dependence of these correlations suggests that
the $v_2$ values are smaller in the proton-going side than those in the
Pb-going side. Finally $v_n$ results are also extracted with four-particle
cumulant method and compared with those obtained with two-particle
correlation method. These results provide new important insights on the
physics underlying the long-range pseudorapidity correlations.
| On behalf of collaboration: | ATLAS |
|---|
Primary author
Sooraj Krishnan Radhakrishnan
(State University of New York (US))
