Invariant-mass distributions for K$^{\ast0}$ (a, b) and $\phi$(c, d) in the transverse momentum range 1.2 $\leq p_{\rm T}$ < 1.4 GeV/$c$ and multiplicity classes 0-20$\%$ and 0-5$\%$, respectively. Upper panels, (a) and (c), report the unlike-sign invariant-mass distribution and the mixed event background (MEB) normalised as described in the text. In lower panels, (b) and (c), the distributions after background subtraction are shown. The K$^{\ast0}$ is fitted with a Breit-Wigner function whereas the $\phi$ meson peak is described by a Voigtian function. A second order polynomial function is used to describe the residual background.