| The $\pT$-differential nuclear modification factor $\RAA$ of muons from heavy-flavour hadron decays at forward rapidity ($2.5 < y < 4$) in central (\cent{0}{10}, top), semi-central (\cent{20}{40}, middle), and peripheral (\cent{60}{80}, bottom) Pb--Pb collisions at \fivenn{} (symbols). Statistical (vertical bars) and systematic uncertainties (open boxes) are shown. The filled boxes centered at $\RAA = 1$ represent the normalisation uncertainty of pp and Pb--Pb measurements. Horizontal bars reflect the bin widths and the values are shown at the centre of the bin. Left: the measured $\RAA$ is compared with the TAMU and SCET models~\cite{He:2014cla,Kang:2016ofv} displayed with their uncertainty bands. Right: the measured $\RAA$ is compared with MC@sHQ+EPOS2 model calculations with pure collisional energy loss (full lines) and a combination of collisional and radiative energy loss (dashed lines)~\cite{Nahrgang:2013xaa,Nahrgang:2013saa}. |