The X(3872) as a mass distribution

Abstract

All existing experimental evidence of the bound state nature of the X(3872) relies on considering its decay products with a finite experimental spectral mass resolution which is typically Delta m >= 2 MeV and much larger than its alleged binding energy, Bx = 0.00(18) MeV. On the other hand, there is a neat cancellation in the 1(++) channel for the invariant D (D) over bar* mass around the threshold between the continuum and bound state contribution. We discuss the impact of this effect for X(3872) at finite temperature, in prompt production in pp collisions data with a finite P T or the lineshapes of specific production experiments of exotic states involving triangle singularities.