Signals consistent with the Bc+(2S) and Bc∗+(2S) states are observed in proton-proton collisions at s=13 TeV, in an event sample corresponding to an integrated luminosity of 143 fb-1, collected by the CMS experiment during the 2015-2018 LHC running periods. These excited bc states are observed in the Bc+π+π- invariant mass spectrum, with the ground state Bc+ reconstructed through its decay to J/ψπ+. The two states are reconstructed as two well-resolved peaks, separated in mass by 29.1±1.5(stat)±0.7(syst) MeV. The observation of two peaks, rather than one, is established with a significance exceeding five standard deviations. The mass of the Bc+(2S) meson is measured to be 6871.0±1.2(stat)±0.8(syst)±0.8(Bc+) MeV, where the last term corresponds to the uncertainty in the world-average Bc+ mass.

Observation of Two Excited Bc+ States and Measurement of the Bc+ (2S) Mass in pp Collisions at s =13 TeV / Sirunyan, A.M., Tumasyan, A., Adam, W., Ambrogi, F., Bergauer, T., Brandstetter, J., Dragicevic, M., Ero, J., Escalante Del Valle, A., Flechl, M., Fruhwirth, R., Jeitler, M., Krammer, N., Kratschmer, I., Liko, D., Madlener, T., Mikulec, I., Rad, N., Schieck, J., Schofbeck, R., et al.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 122:13(2019), p. 132001. [10.1103/PhysRevLett.122.132001]

Observation of Two Excited Bc+ States and Measurement of the Bc+ (2S) Mass in pp Collisions at s =13 TeV

Cipriani M.;Del Re D.;Longo E.;Organtini G.;Paramatti R.;Quaranta C.;Rahatlou S.;Santanastasio F.;
2019

Abstract

Signals consistent with the Bc+(2S) and Bc∗+(2S) states are observed in proton-proton collisions at s=13 TeV, in an event sample corresponding to an integrated luminosity of 143 fb-1, collected by the CMS experiment during the 2015-2018 LHC running periods. These excited bc states are observed in the Bc+π+π- invariant mass spectrum, with the ground state Bc+ reconstructed through its decay to J/ψπ+. The two states are reconstructed as two well-resolved peaks, separated in mass by 29.1±1.5(stat)±0.7(syst) MeV. The observation of two peaks, rather than one, is established with a significance exceeding five standard deviations. The mass of the Bc+(2S) meson is measured to be 6871.0±1.2(stat)±0.8(syst)±0.8(Bc+) MeV, where the last term corresponds to the uncertainty in the world-average Bc+ mass.
2019
Particle Physics; LHC; Bc+ States; CMS
01 Pubblicazione su rivista::01a Articolo in rivista
Observation of Two Excited Bc+ States and Measurement of the Bc+ (2S) Mass in pp Collisions at s =13 TeV / Sirunyan, A.M., Tumasyan, A., Adam, W., Ambrogi, F., Bergauer, T., Brandstetter, J., Dragicevic, M., Ero, J., Escalante Del Valle, A., Flechl, M., Fruhwirth, R., Jeitler, M., Krammer, N., Kratschmer, I., Liko, D., Madlener, T., Mikulec, I., Rad, N., Schieck, J., Schofbeck, R., et al.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 122:13(2019), p. 132001. [10.1103/PhysRevLett.122.132001]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1343978
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