Invariant mass of ($^{3}\rm{He}$,$\pi^-$) (left) and ($^{3}\overline{\rm{He}}$,$\pi^+$) (right) for events with 10-50% centrality in the pair 2 $\leq \pt $< 10 Gev/$c$ interval. The data points are shown as filled circles, while the squares represent the background distributionas described in the text. The curve represents thefunction used to perform the fit and used to evaluate the background and the raw signal. The significance in $\pm$3$\sigma$ around the peak is 3.5 and 3.0 for the invariant massdistribution of ($^{3}\rm{He}$,$\pi^-$) and ($^{3}\overline{\rm{He}}$,$\pi^+$), respectively.