Speaker
Michael Felix Clark
(Columbia University)
Description
ATLAS measurement of azimuthal correlations between particle pairs at
large pseudorapidity separation in pp and pPb collisions are presented.
The data were collected using a combination of the minimum-bias and high
track-multiplicity triggers. A detailed study of the dependence of
two-particle correlations on the charged particle multiplicity,
transverse momentum of the pair constituents and the pseudorapidity
separation between particles forming a pair is shown. Measurements of
multi-particle cumulants in the azimuthal angles of produced particles
in wide pseudorapidity (|η|<2.5) and multiplicity ranges, with the aim
to extract a single particle anisotropy coefficient, v1-v5, are also
presented. These measurements can help to understand the origin of the
long-range correlations seen in high-multiplicity pp and p+Pb collisions.
In addition, one and three-dimensional HBT radii in p+Pb collisions are
presented as a function of event centrality. An estimation of dE/dx in
the pixel detector is used to identify charged pions. These particles
are selected from |η| < 2.5 and the measurement is performed in several
pair-average momentum (kT) bins from 0.1 GeV to 1.0 GeV. The measured
source sizes are observed to increase with collision centrality. The
contribution to the correlation function from hard processes is studied
and a novel method for tuning the amplitude of this background in the
data is introduced.
Author
Michael Ryan Clark
(Columbia University (US))
