$D^+D^-$ hadronic atom and its production in $pp$ and $p\bar{p}$ collisions

TL;DR

This paper predicts the properties, decay width, and production cross sections of the $D^+D^-$ hadronic atom, called dionium, using effective field theory and lattice inputs, and discusses its potential observation at collider experiments.

Contribution

It provides the first detailed theoretical prediction of the mass, decay width, and production rates of the $D^+D^-$ hadronic atom, including estimates for experimental detection.

Findings

Mass of dionium predicted at 3739.3 MeV

Decay width into $D^0\bar D^0$ channel estimated at ~1.8 keV

Production rates at LHCb, CMS, and PANDA estimated

Abstract

There must be Coulomb bound states of a pair of hadrons, which are stable against the strong interaction, with opposite electric charges. Such bound states are hadronic atoms. We study the properties and the production of the ground-state $D^+D^-$ hadronic atom $A_{D^+D^-}$, called dionium, with quantum numbers $J^{PC}=0^{++}$. Using a nonrelativistic effective field theory for the $D^0\bar{D}^0$-$D^+D^-$ coupled-channel system, the mass of the ground-state dionium is predicted to be $(3739.3 \pm 0.1)~\text{MeV}$, with the binding energy reduced by about 10% compared to the Coulomb binding energy due to the strong interaction. Its width for the decay into the neutral $D^0\bar D^0$ channel is predicted to be $1.8^{+1.4}_{-0.6}$ keV using lattice inputs for the $D\bar D$ strong interaction. The cross section for the inclusive prompt production of the dionium at CMS and LHCb and that for the direct production $p\bar p\to A_{D^+D^-}$ at PANDA are estimated at an order-of-magnitude level. In particular, we expect that $\mathcal{O}(10^3\sim 10^5)$ events of the reaction chain $p\bar p\to A_{D^+D^-}\to D^0\bar D^0 \to K^-\pi^+K^+\pi^-$ can be collected at PANDA, and valuable information on the charmed meson interaction and on understanding charmoniumlike states will be obtained.