Using pp collision data corresponding to an integrated luminosity of 8.5 fb-1 recorded by the LHCb experiment at center-of-mass energies of s=7, 8, and 13 TeV, the observation of an excited Bc+ state in the Bc+π+π- invariant-mass spectrum is reported. The observed peak has a mass of 6841.2±0.6(stat)±0.1(syst)±0.8(Bc+) MeV/c2, where the last uncertainty is due to the limited knowledge of the Bc+ mass. It is consistent with expectations of the Bc∗(2S31)+ state reconstructed without the low-energy photon from the Bc∗(1S31)+→Bc+γ decay following Bc∗(2S31)+→Bc∗(1S31)+π+π-. A second state is seen with a global (local) statistical significance of 2.2σ (3.2σ) and a mass of 6872.1±1.3(stat)±0.1(syst)±0.8(Bc+) MeV/c2, and is consistent with the Bc(2S10)+ state. These mass measurements are the most precise to date.

Aaij, R., Abellan Beteta, C., Adeva, B., Adinolfi, M., Aidala, C., Ajaltouni, Z., et al. (2019). Observation of an Excited Bc+ State. PHYSICAL REVIEW LETTERS, 122(23), 232001 [10.1103/PhysRevLett.122.232001].

Observation of an Excited Bc+ State

Belloli N.;Borsato M.;Calvi M.;Carniti P.;Fazzini D.;Gotti C.;Martinelli M.;Petruzzo M.;
2019

Abstract

Using pp collision data corresponding to an integrated luminosity of 8.5 fb-1 recorded by the LHCb experiment at center-of-mass energies of s=7, 8, and 13 TeV, the observation of an excited Bc+ state in the Bc+π+π- invariant-mass spectrum is reported. The observed peak has a mass of 6841.2±0.6(stat)±0.1(syst)±0.8(Bc+) MeV/c2, where the last uncertainty is due to the limited knowledge of the Bc+ mass. It is consistent with expectations of the Bc∗(2S31)+ state reconstructed without the low-energy photon from the Bc∗(1S31)+→Bc+γ decay following Bc∗(2S31)+→Bc∗(1S31)+π+π-. A second state is seen with a global (local) statistical significance of 2.2σ (3.2σ) and a mass of 6872.1±1.3(stat)±0.1(syst)±0.8(Bc+) MeV/c2, and is consistent with the Bc(2S10)+ state. These mass measurements are the most precise to date.
Articolo in rivista - Articolo scientifico
Excited Bc+ State
English
2019
122
23
232001
232001
none
Aaij, R., Abellan Beteta, C., Adeva, B., Adinolfi, M., Aidala, C., Ajaltouni, Z., et al. (2019). Observation of an Excited Bc+ State. PHYSICAL REVIEW LETTERS, 122(23), 232001 [10.1103/PhysRevLett.122.232001].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/242941
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