September 14, 2021
Europe/Zurich timezone

What can we learn from the width of the $T_{cc}^+$ tetraquark?

Sep 14, 2021, 2:00 PM


Mitja Rosina


The width of the $T_{cc}^+$ tetraquark (dimeson) is expected to differ considerably from the widths of its constituent $D^{*0}$ and $D^{*+}$. Unfortunately, reliable values of the $D^{*0}$ and $T_{cc}^+$ widths are not yet known and at least theoretical estimates would be welcome. An interesting effect is due to the charge splitting of the
$(D^{*+})D^0$ and $(D^{*0})D^+$ thresholds,
therefore $T_{cc}^+$ will not have a pure isospin coupling
$T_{cc}^+ = [(D^{*+})D^0 - (D^{*0})D^+]/\sqrt{2}$ and the actual composition may be seen in branching ratios. The width of $T_{cc}^+$ may depend strongly on threshold effects since its energy is not discrete and its peak extends beyond the lowest threshold, making it partially unstable and therefore broader. I shal try to estimate some of these effects.

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