$D^0 D^0 \pi^+$ mass distribution in the production of the $T_{cc}$ exotic state

Abstract

We perform a unitary coupled channel study of the interaction of the $D^{*+} D^0, D^{*0} D^+$ channels and find a state barely bound, very close to isospin $I=0$. We take the experimental mass as input and obtain the width of the state and the $D^0 D^0 \pi^+$ mass distribution. When the mass of the $T_{cc}$ state quoted in the experimental paper from raw data is used, the width obtained is of the order of the $80 \;{\rm keV}$, small compared to the value given in that work. Yet, when the mass obtained in an analysis of the data considering the experimental resolution is taken, the width obtained is about $43 \;{\rm keV}$ and both the width and the $D^0 D^0 \pi^+$ mass distribution are in remarkable agreement with the results obtained in that latter analysis.