Two narrow resonant states are observed in the Λ 0 b K − π + mass spectrum using a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the LHCb experiment and corresponding to an integrated luminosity of 6     fb − 1 . The minimal quark content of the Λ 0 b K − π + system indicates that these are excited Ξ 0 b baryons. The masses of the Ξ b ( 6327 ) 0 and Ξ b ( 6333 ) 0 states are m [ Ξ b ( 6327 ) 0 ] = 6327.2 8 + 0.23 − 0.21 ± 0.12 ± 0.24 and m [ Ξ b ( 6333 ) 0 ] = 6332.6 9 + 0.17 − 0.18 ± 0.03 ± 0.22     MeV , respectively, with a mass splitting of Δ m = 5.4 1 + 0.26 − 0.27 ± 0.12     MeV , where the uncertainties are statistical, systematic, and due to the Λ 0 b mass measurement. The measured natural widths of these states are consistent with zero, with upper limits of Γ [ Ξ b ( 6327 ) 0 ] < 2.20 ( 2.56 ) and Γ [ Ξ b ( 6333 ) 0 ] < 1.60 ( 1.92 )     MeV at a 90% (95%) credibility level. The significance of the two-peak hypothesis is larger than nine (five) Gaussian standard deviations compared to the no-peak (one-peak) hypothesis. The masses, widths, and resonant structure of the new states are in good agreement with the expectations for a doublet of 1 D Ξ 0 b resonances.

Observation of two new excited Ξb0 states decaying to Λb0 K-π+ / Aaij, R., Abdelmotteleb, A.S.W., Abellán Beteta, C., Ackernley, T., Adeva, B., Adinolfi, M., Afsharnia, H., Agapopoulou, C., Aidala, C.A., Aiola, S., Ajaltouni, Z., Akar, S., Albrecht, J., Alessio, F., Alexander, M., Alfonso Albero, A., Aliouche, Z., Alkhazov, G., Alvarez Cartelle, P., Amato, S., et al.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 128:16(2022). [10.1103/PhysRevLett.128.162001]

Observation of two new excited Ξb0 states decaying to Λb0 K-π+

Casse, G.;Sarti, A.;
2022

Abstract

Two narrow resonant states are observed in the Λ 0 b K − π + mass spectrum using a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the LHCb experiment and corresponding to an integrated luminosity of 6     fb − 1 . The minimal quark content of the Λ 0 b K − π + system indicates that these are excited Ξ 0 b baryons. The masses of the Ξ b ( 6327 ) 0 and Ξ b ( 6333 ) 0 states are m [ Ξ b ( 6327 ) 0 ] = 6327.2 8 + 0.23 − 0.21 ± 0.12 ± 0.24 and m [ Ξ b ( 6333 ) 0 ] = 6332.6 9 + 0.17 − 0.18 ± 0.03 ± 0.22     MeV , respectively, with a mass splitting of Δ m = 5.4 1 + 0.26 − 0.27 ± 0.12     MeV , where the uncertainties are statistical, systematic, and due to the Λ 0 b mass measurement. The measured natural widths of these states are consistent with zero, with upper limits of Γ [ Ξ b ( 6327 ) 0 ] < 2.20 ( 2.56 ) and Γ [ Ξ b ( 6333 ) 0 ] < 1.60 ( 1.92 )     MeV at a 90% (95%) credibility level. The significance of the two-peak hypothesis is larger than nine (five) Gaussian standard deviations compared to the no-peak (one-peak) hypothesis. The masses, widths, and resonant structure of the new states are in good agreement with the expectations for a doublet of 1 D Ξ 0 b resonances.
2022
bottom baryons, mass, hadrons
01 Pubblicazione su rivista::01a Articolo in rivista
Observation of two new excited Ξb0 states decaying to Λb0 K-π+ / Aaij, R., Abdelmotteleb, A.S.W., Abellán Beteta, C., Ackernley, T., Adeva, B., Adinolfi, M., Afsharnia, H., Agapopoulou, C., Aidala, C.A., Aiola, S., Ajaltouni, Z., Akar, S., Albrecht, J., Alessio, F., Alexander, M., Alfonso Albero, A., Aliouche, Z., Alkhazov, G., Alvarez Cartelle, P., Amato, S., et al.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 128:16(2022). [10.1103/PhysRevLett.128.162001]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1672049
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