Productions of $T_{cc}$ and its SU(3)-flavor symmetry and heavy quark spin symmetry partners in $B_c$ decays

TL;DR

This work uses a contact-range effective field theory with HQSS and SU(3) flavor symmetry to predict a multiplet of doubly charmed hadronic molecules centered on the observed $T_{cc}$ as a $DD^*$ bound state. By enforcing identical short-range potentials across the six related $DD^{(*)}$-type configurations, it predicts five additional partners and their HQSS relatives, then computes their partial decays and production in exclusive $B_c$ decays via tree and triangle diagrams. The study finds that the $T_{cc}$-SU(3) partners $T_{ccs}^{+}$ and $T_{ccs}^{++}$ have relatively favorable widths and decay patterns, and that the production rates in $B_c$ decays combined with LHC Run 3/HL-LHC yields make $T_{ccs}^{++}$ and $T_{ccs}^{*++}$ likely to be observed, while $T_{cc}$ and $T_{cc}^{*}$ are more challenging to detect. These results offer concrete channels and branching fractions to test the molecular picture of $T_{cc}$ and guide experimental searches for doubly charmed tetraquark states in $B_c$ decays.

Abstract

Inspired by the observation of the doubly charmed tetraquark state $T_{cc}$ at $pp$ collisions in the inclusive processes, we systematically investigate the production of doubly charmed tetraquark states in exclusive $B_c$ decays. In this work, we assume the $T_{cc}$ as a $DD^*$ bound state, and then predict the masses of its heavy quark spin symmetry partner $D^*D^*$ (denoted by $T_{cc}^{*}$) as well as their SU(3)-flavor symmetry partners, i.g., $D_sD^*/D_s^*D$ (denoted by $T_{ccs}^{+}$ and $T_{ccs}^{++}$) and $D^*D_s^*$ (denoted by $T_{ccs}^{*+}$ and $T_{ccs}^{*++}$), using the contact range effective field theory. Within the molecular picture, we compute their partial decays and production rates in $B_c$ meson decays. We identify the decays $B_c \to D^0D^0π^+\bar{D}^0 $ and $B_c \to D_s^+ D^{0} π^+{D}^{-}$ as promising channels to observe the tetraquark states $T_{cc}^{(*)}$ and $T_{ccs}^{(*)++}$, respectively. Finally, by combining these results with $B_c$ production cross sections, we estimate the expected event yields for these states in the upcoming LHC Run 3 and 4. Our results indicate that the $T_{ccs}^{+}$ and $T_{ccs}^{*++}$ states are likely to be observed in $B_c$ decays, while it is quite difficult for the $T_{cc}$ and $T_{cc}^{*}$ states.

Figures (4)

• Figure 1: Tree diagrams responsible for the three-body decays of the $T_{cc}$(a-b), $T_{ccs}^{+}$(c-d), and $T_{ccs}^{++}$(e-f) states.
• Figure 2: Tree diagrams responsible for the three-body decays of the $T_{cc}^*$(a-b), $T_{ccs}^{*+}$(c-d), and $T_{ccs}^{*++}$(e-f) states.
• Figure 3:
• Figure 4: Triangle diagrams responsible for the productions of the $T_{cc}$(a-d), $T_{ccs}^+$(e-h), $T_{ccs}^{++}$(i-l), $T_{cc}^*$(m-p), $T_{ccs}^{*+}$(q-t), and $T_{ccs}^{*++}$(u-x) states in $B_c$ meson decays.