Observation of two excited &lt;em&gt;B&lt;/em&gt;&lt;sub&gt;c&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt; states and measurement of the &lt;em&gt;B&lt;/em&gt;&lt;sub&gt;c&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt; (2&lt;em&gt;S&lt;/em&gt;) mass in &lt;em&gt;pp &lt;/em&gt;collisions at √&lt;em&gt;s&lt;/em&gt; = 13 TeV

Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Brandstetter, J.; Dragicevic, M.; Erö, J.; Escalante Del Valle, A.; Flechl, M.; Caminada, L.; Deiters, K.; Erdmann, W.; Horisberger, R.; Ingram, Q.; Kaestli, H.C.; Kotlinski, D.; Langenegger, U.; Rohe, T.; Wiederkehr, S.A.; Woods, N.

doi:10.1103/PhysRevLett.122.132001

Observation of two excited B_c⁺ states and measurement of the B_c⁺ (2S) mass in pp

Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Bergauer T, Brandstetter J, Dragicevic M, Erö J, Escalante Del Valle A, Flechl M, Caminada L, Deiters K, Erdmann W, Horisberger R, Ingram Q, Kaestli HC, Kotlinski D, Langenegger U, Rohe T, Wiederkehr SA, Woods N, et al.

Citation

Sirunyan, A. M., Tumasyan, A., Adam, W., Ambrogi, F., Bergauer, T., Brandstetter, J., … Woods, N. (2019). Observation of two excited B_c⁺ states and measurement of the B_c⁺ (2S) mass in pp collisions at √s = 13 TeV. Physical Review Letters, 122(13), 132001 (17 pp.). https://doi.org/10.1103/PhysRevLett.122.132001

Persistent URL https://www.dora.lib4ri.ch/psi/islandora/object/psi:27805

Signals consistent with the B_c⁺(2S) and B*_c⁺(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 b¯c states are observed in the B⁺_cπ⁺π^- invariant mass spectrum, with the ground state B_c⁺ 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 B_c⁺(2S) meson is measured to be 6871.0 ± 1.2(stat) ± 0.8(syst) ±0 .8(B_c⁺) MeV, where the last term corresponds to the uncertainty in the world-average B_c⁺ mass.