Probing the long-range structure of the Tcc+ with the strong and electromagnetic decays

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*degrees 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(+) -> (DD0)-D-0 pi(+), T-cc(+) -> (D-D0)pi(0) and radiative decays (D+D0)gamma. Our results show that the decay width of T-cc(+ )-> (DD0)-D-0 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 vertical bar D*D-+(0)> dominated bound state. The total strong and radiative width in the single channel limit and isospin singlet limit arc given as 59.7(-4.4)(+4.6) keV and 46.7(-2.9)(+2.7) 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 arc available.

Automated summary

The study focuses on the characteristics of the doubly charmed tetraquark state T-cc(+), including binding energy, coupling constants, and various decay channels. The results indicate that the decay width of T-cc(+) -> (DD0)-D-0 pi(+) is the largest, suggesting this as the dominant experimental observation channel.