Probing the long-range structure of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msubsup><mml:mi>T</mml:mi><mml:mrow><mml:mi>c</mml:mi><mml:mi>c</mml:mi></mml:mrow><mml:mo>+</mml:mo></mml:msubsup></mml:math> with the strong and electromagnetic decays

Abstract

Very recently, the LHCb Collaboration reported the doubly charmed tetraquark state ${T}_{cc}^{+}$ below the ${D}^{*+}{D}^{0}$ threshold about 273 keV. As a very near-threshold state, its long-distance structure is very important. In the molecular scheme, we relate the coupling constants of ${T}_{cc}^{+}$ with ${D}^{*0}{D}^{+}$ and ${D}^{*+}{D}^{0}$ to its binding energy and mixing angle of two components with a coupled-channel effective field theory. With the coupling constants, we investigate the kinetically allowed strong decays ${T}_{cc}^{+}\ensuremath{\rightarrow}{D}^{0}{D}^{0}{\ensuremath{\pi}}^{+}$, ${T}_{cc}^{+}\ensuremath{\rightarrow}{D}^{+}{D}^{0}{\ensuremath{\pi}}^{0}$ and radiative decays ${D}^{+}{D}^{0}\ensuremath{\gamma}$. Our results show that the decay width of ${T}_{cc}^{+}\ensuremath{\rightarrow}{D}^{0}{D}^{0}{\ensuremath{\pi}}^{+}$ is the largest one, which is just the experimental observation channel. Our theoretical total strong and radiative widths are in favor of the ${T}_{cc}^{+}$ as a $|{D}^{*+}{D}^{0}⟩$ dominated bound state. The total strong and radiative width in the single channel limit and isospin singlet limit are given as ${59.7}_{\ensuremath{-}4.4}^{+4.6}\text{ }\text{ }\mathrm{keV}$ and ${46.7}_{\ensuremath{-}2.9}^{+2.7}\text{ }\text{ }\mathrm{keV}$, respectively. Our calculation is cutoff-independent and without prior isospin assignment. The absolute partial widths and ratios of the different decay channels can be used to test the structure of ${T}_{cc}^{+}$ state when the updated experimental results are available.

Topics & Concepts