Speaker
Description
Bose-Einstein correlations between identified charged pions are measured for $p$+Pb
collisions at $\sqrt{s_{\mathrm{NN}}}=5.02~\mathrm{TeV}$ with the ATLAS detector with
a total integrated luminosity of $28~\inb$. Pions are identified using ionization
energy loss measured in the pixel detector. Two-particle correlation functions and
the extracted source radii are presented as a function of average transverse pair
momentum ($k_{\mathrm{T}}$) and rapidity ($y^{*}_{k}$) as well as collision centrality.
Pairs are selected with a rapidity $-2 < y^{*}_{k} < 1$ and with an average transverse
momentum $0.1 < k_{\mathrm{T}} < 0.8 \GeV$. The effect on the two-particle correlation
function from jet fragmentation is studied, and a new method for constraining its
contributions to the measured correlations is described. The measured source sizes
are substantially larger in more central collisions and are observed to decrease with
increasing pair $k_{\mathrm{T}}$. Radii are also evaluated in intervals of $y^{*}_{k}$
and a correlation with the local multiplicity $dN/dy^{*}$ is demonstrated.
The scaling of the extracted radii with the mean number of participants is also used
to compare a selection of initial-geometry models.
| Collaboration | ATLAS |
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