User

Roles
Anonymous

The $M_{\mu\mu}$ distribution in the 5--60\% centrality interval and 2 $< \pt <$ 15 GeV/$c$

Figure Information
Scope: PWG
PWG-DQ (Dileptons and Quarkonia)
Energy
5.02 TeV
System
Pb-Pb
Figure Group
Measurement of Upsilon(1S) v2 at forward rapidity in Pb-Pb collisions at 5.02 TeV - published
Figure Image
Figure image (.eps)
2019-07-09-Fig1_01072019.eps
Figure image (.pdf)
2019-07-09-Fig1_01072019.pdf
Figure Caption

The $M_{\mu\mu}$ distribution in the 5--60\% centrality interval and 2 $< \pt <$ 15 GeV/$c$ fitted with a combination of an
    extended Crystal Ball function for the signal and a Variable-Width Gaussian function for the background.

Detail description

The dimuon invariant mass ($M_{\mu\mu}$) distribution is
fitted with a combination of an extended Crystal Ball (CB2) function for the $\Upsilon$(1S) signal and a Variable-Width Gaussian (VWG) function with a quadratic dependence of the width on $M_{\mu\mu}$ for the background~\cite{ALICE-PUBLIC-2015-006}.
A binned maximum-likelihood fit is employed.
The $\Upsilon$(1S) peak position and width are left free, while the CB2 tail parameters are fixed to the values extracted from Monte Carlo simulations~\cite{Acharya:2018mni}. The $\Upsilon$(2S) and $\Upsilon$(3S) signals
are included in the fit. Their peak positions and widths are fixed to those of the $\Upsilon$(1S) scaled by the ratio of their nominal masses to the nominal mass of the $\Upsilon$(1S). An example of the $M_{\mu\mu}$ fit is shown in the left panel of Fig.~\ref{fig:fits}. It is worth noting that no statistically significant $\Upsilon$(3S) is observed in any of the studied centrality and \pt\ intervals, and thus it is not considered in the further analysis.