Interactions of the doubly charmed state $$T_{cc} ^+$$ with a hadronic medium

Abstract

We calculate the cross sections of the processes $$T_{cc}^+ \pi , T_{cc}^+ \rho \rightarrow D^{(*)} D^{(*)} $$ T cc + π , T cc + ρ → D ( ∗ ) D ( ∗ ) and of the corresponding inverse reactions. We use effective Lagrangians to account for the couplings between light and heavy mesons, and give special attention to the form factors in the vertices. Using QCD sum rules we calculate here for the first time the $$ T_{cc}^+ - D - D^*$$ T cc + - D - D ∗ form factor. The $$T_{cc}^+$$ T cc + absorption cross sections are found to be larger than the production ones. We compare our results with the only other existing estimate of these quantities, presented in a work by J. Hong, S. Cho, T. Song and S. H. Lee, in which the authors employed the quasi-free approximation. We find cross sections which are one order of magnitude smaller.

An Effective Field Theory Treatment of the Production and Annihilation of Magnetic Monopoles and their Relic Abundance

“…In this paper, we obtain the thermal-averaged cross sections for monopole absorption, in analogy with recent work on the open flavour tetraquark state X(2900) in a hot hadronic medium Ref. [27,28]. We obtained the thermally averaged cross section < σv rel > for the absorption of monopoles with an exact formula obtained by Cannoni and which is valid with an effective field theory where the masses of the annihilation products (here, the quarks) are much smaller than the monopole masses [29][30][31].…”