Study of $D_{s1}(2460)^{+}\to D_{s}^{+}\pi^{+}\pi^{-}$ in $B\to {\bar{D}}^{()}D_{s}^{+}\pi^{+}\pi^{-}$ decays

• Main Authors: Albrecht, J, Amey, J. L, Anderlini, L, Ao, D, Da Silva, R. Ataíde, Bachmann, S, Belous, K, Belyaev, I, Blake, T, Bolzonella, R, Bonacci, R. B, Bowcock, T. J. V, Rodriguez, A. Brea, Butter, J. S, Caillet, A. C, Ramirez, S. Calderon, Caravaca-Mora, R, Caspary, R, Cholak, S, Chulikov, V, Congedo, L, Currie, R, Dai, X, De Paula, L, Delaney, B, Didenko, S, Dobishuk, V, Donohoe, A. M, Egorychev, A, Evans, T, Forty, R, Foulds-Holt, D, Führing, Q, Gao, T. Q, Gaspar, C, Girardey, L, Giugliano, C, Gys, T, Hao, L, Hennessy, K, Henry, L, Hu, X, Huang, W, Hushchyn, M, Jiang, Y. J, Juszczak, I, Karacson, M, Khreich, G, Krokovny, P, Kulikova, E, Gomez, C. Landesa, Li, M, Li, P, Liu, G, Lucarelli, C, Luo, Y, Mackey, L. M, Maevskiy, A, Malentacca, L, Gomez, D. Martinez, Merli, A, Miralles, T, Moise, R. D, Morren, W, Oeser, T, Osthues, D, Paolucci, L, Passaleva, G, Perret, P, Pica, L, Pinci, D, Placinta, V, Polukhina, N, Punzi, G, Rademacker, J. H, Reich, J, Fernandez, R. A. Ruiz, Saitta, B, Sarnatskiy, A, Schmelling, M, Schmitt, S, Soares, M. Senghi, Shangase, D. M, Shapkin, M, Smith, K, Spiridenkov, E, Stahl, S, Thompson, D. J. D, Machado, D. Torres, Trippl, C, Uecker, L. H, Gomez, R. Vazquez, Vecchi, S, Ward, J. A, Wilkinson, M. K, Williams, M. R. J, Winn, M, Witek, M, Zhang, D, Zheng, X. Z
• Format: Journal Article
• Language: English
• Published: 05-11-2024
• Subjects: Physics - High Energy Physics - Experiment
• DOI: 10.48550/arxiv.2411.03399

An amplitude analysis of the $D_{s1}(2460)^+\to D_{s}^{+}\pi^{+}\pi^{-}$
transition is performed simultaneously in $B^{0}\to
D^{-}D_{s}^{+}\pi^{+}\pi^{-}$, $B^{+}\to{\bar{D}}^{0} D_{s}^{+}\pi^{+}\pi^{-}$,
and $B^{0}\to D^{*-}D_{s}^{+}\pi^{+}\pi^{-}$ decays. The study is based on a
data sample of proton-proton collisions recorded with the LHCb detector at
centre-of-mass energies of $\sqrt{s}=7,8,$ and $13\,$TeV, corresponding to a
total integrated luminosity of $9\,\rm{fb}^{-1}$. A clear double-peak structure
is observed in the $m(\pi^{+}\pi^{-})$ spectrum of the $D_{s1}(2460)^{+}\to
D_{s}^{+}\pi^{+}\pi^{-}$ decay. The data can be described either with a model
including $f_0(500)$, $f_0(980)$ and $f_2(1270)$ resonances, in which the
contributions of $f_0(980)$ and $f_2(1270)$ are unexpectedly large, or with a
model including $f_0(500)$, a doubly charged open-charm tetraquark state
$T_{c\bar{s}}^{++}$ and its isospin partner $T_{c\bar{s}}^{0}$. If the former
is considered implausible, the $T_{c\bar{s}}$ states are observed with high
significance, and the data are consistent with isospin symmetry. When imposing
isospin constraints between the two $T_{c\bar{s}}$ states, their mass and width
are determined to be $2327\pm13\pm13\,$MeV and $96\pm16\,^{+170}_{-23}\,$MeV,
respectively, where the first uncertainty is statistical and the second is
systematic. The mass is slightly below the $DK$ threshold, and a spin-parity of
$0^+$ is favoured with high significance.