Observation of the Ξb-→ψ(2S)Ξ- decay and studies of the Ξb(5945)0 baryon in proton-proton collisions at s=13TeV

• Published in: Physical review. D 2024-07, Vol.110 (1)
• Main Authors: Mikulec, I., Vanden Bemden, M., Shumka, E., Wang, D., Yang, H., Grimault, C., Spah, J. L., Stein, A., Bhattacharya, S., Borras, K., Jeppe, L., Leyva Pernia, D., Milella, G., Schwanenberger, C., Labe, F., Raciti, B., Schröder, M., Stadie, H., Lawhorn, J. M., Panagiotou, A., Szillasi, Z., Sandeep, K., Ameen, M. M., Kumar, D., Jaiswal, A., Abbrescia, M., Colaleo, A., Iaselli, G., Bisello, D., Ronchese, P., Spiga, D., Del Re, D., Pelliccioni, M., Trocino, D., Gwak, P., Lee, S., Choi, J., Kim, J., Ha, S., León Coello, M., Lopez-Fernandez, R., Sánchez Hernández, A., Ahmad, A., Bluj, M., Leonardo, N., Escalante Del Valle, A., Fernández Del Val, D., Pérez-Calero Yzquierdo, A., Baechler, J., Pierini, M., Datta, K., Valsecchi, D., Jofrehei, A., Lin, W., Dolek, F., Guler, Y., Gurpinar Guler, E., Simsek, C., Isildak, B., Robertshaw, L., Harder, K., Uchida, K., Hatakeyama, K., Sutantawibul, C., Wilson, J., Cosby, C., Erbacher, R., Cousins, R., Nunez Del Prado, A., Barzdukas, A., Roberts, A., Zipper, N., Green, D., Zoi, I., Mitselmakher, G., Rudrabhatla, S., Yoo, J., Blumenfeld, B., Rebassoo, F., Wang, Z., Haza, G., Kharchilava, A., Jessop, C., Moore, C., Osherson, M., Bylsma, B., Stickland, D., Barnes, V. E., Dolen, J., Carnahan, T., Geurts, F. J. M., Khukhunaishvili, A., Popova, E., Heindl, M., Higginbotham, S., Hussain, A., Mondal, S., Krasnikov, N., Shmatov, S., Smirnov, V.
• Format: Article
• Language: English
• Subjects: PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
• ISSN: 2470-0010

The first observation of the decay $Ξ^{-}_{b}$ → $ψ$(2S)$Ξ^-$ and measurement of the branching ratio of $Ξ^{-}_{b}$ → $ψ$(2S)$Ξ^-$ to $Ξ^{-}_{b}$ → $J/ψ$$Ξ^-$ are presented. The $J/ψ$ and $ψ$(2S) mesons are reconstructed using their dimuon decay modes. The results are based on proton-proton colliding beam data from the LHC collected by the CMS experiment at $\sqrt{s}$ = 13 TeV in 2016–2018, corresponding to an integrated luminosity of 140 fb-1. The branching fraction ratio is measured to be $\mathcal{B}$($Ξ^{-}_{b}$ → $ψ$(2S)$Ξ$-)/$\mathcal{B}$($Ξ^{-}_{b}$ → $J/ψ$$Ξ^{-}$) = $0.84^{+0.21}_{-0.19}$(stat) 0.10(syst) ± 0.02($\mathcal{B}$), where the last uncertainty comes from the uncertainties in the branching fractions of the charmonium states. New measurements of the $Ξ_b$(5945)0 baryon mass and natural width are also presented, using the $Ξ^{-}_{b}$$π^+$ final state, where the $Ξ^{-}_{b}$ baryon is reconstructed through the decays $J/ψ$$Ξ^-$, $ψ$(2S)$Ξ^-$, $J/ψΛK$-, and $J/ψΣ$0$K$-. Finally, the fraction of $Ξ^{-}_{b}$ baryons produced from $Ξ_b$(5945)0 decays is determined.