Measurement of deuteron spectra and elliptic flow in Pb--Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV at the LHC

Submission Date: 
23/07/2017
Article Information
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System: 
Pb-Pb
Energy: 
2.76 TeV
Abstract Plain Text: 
The transverse momentum (\pt) spectra and elliptic flow coefficient (\vtwo) of deuterons and anti-deuterons at mid-rapidity ($|y|<0.5$) are measured with the ALICE detector at the LHC in \PbPb\ collisions at \s\ =~2.76~TeV. 
The measurement of the \pt\ spectra of  (anti-)deuterons is done up to 8~\gmom\ in 0-10\% centrality  class and up to 6~\gmom\ in 10--20\% and 20--40\% centrality classes. The \vtwo\ is measured in the 0.8~$<$~\pt~$<~$5~\gmom\  interval and in six different centrality intervals (\mbox{0--5\%}, \mbox{5--10\%}, \mbox{10--20\%}, \mbox{20--30\%}, \mbox{30--40\%} and \mbox{40--50\%}) using the scalar product technique. 
Measured \pio$^{\pm}$, K$^{\pm}$  and p+$\overline{\mathrm{p}}$ transverse-momentum spectra and \vtwo\ are used to predict the deuteron \pt\ spectra  and \vtwo\ within the Blast-Wave model. 
The predictions are able to reproduce the \vtwo\ coefficient in the measured \pt\ range and the transverse-momentum spectra for \pt~$>$~1.8~\gmom\ within the experimental uncertainties.
The measurement of the coalescence parameter $B_2$ is performed, showing a \pt\ dependence in contrast with the simplest coalescence model, which fails to reproduce also the measured \vtwo\ coefficient. 
In addition, the coalescence parameter $B_2$  and the elliptic flow coefficient in the 20--40\% centrality interval are compared  with the  AMPT model which is able, in its version without string melting, to reproduce the measured \vtwo(\pt) and the $B_2$(\pt) trend.