Observation of the chi(b1)(3P) and chi(b2)(3P) and measurement of their masses

• Main Authors: Sirunyan, A. M., Tumasyan, A. R., Adam, Wolfgang, Ambrogi, Federico, Asilar, Ece, Md. Ali, Mohd. Adli
• Format: Article
• Language: English; English; English
• Published: American Physical Society 2018
• Subjects: Q Science (General); QC Physics
• Online Access: http://irep.iium.edu.my/70106/1/70106_Observation%20of%20the%20chi%28b1%29%283P%29%20and%20chi%28b2%29%283P%29.pdf; http://irep.iium.edu.my/70106/2/70106_Observation%20of%20the%20chi%28b1%29%283P%29%20and%20chi%28b2%29%283P%29_WOS.pdf; http://irep.iium.edu.my/70106/13/70106_Observation%20of%20the%20%CF%87b1%20%283P%29%20and%20%CF%87b2%20_scopus.pdf; http://irep.iium.edu.my/70106/; https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.121.092002

The χb1ð3PÞ and χb2ð3PÞ states are observed through their ϒð3SÞγ decays, using an event sample of proton-proton collisions collected by the CMS experiment at the CERN LHC. The data were collected at a center-of-mass energy of 13 TeV and correspond to an integrated luminosity of 80.0 fb−1. The ϒð3SÞ mesons are identified through their dimuon decay channel, while the low-energy photons are detected after converting to eþe− pairs in the silicon tracker, leading to a χbð3PÞ mass resolution of 2.2 MeV. This is the first time that the J ¼ 1 and 2 states are well resolved and their masses individually measured: 10513.42 0.41ðstatÞ 0.18ðsystÞ MeV and 10524.02 0.57ðstatÞ 0.18ðsystÞ MeV; they are determined with respect to the world-average value of the ϒð3SÞ mass, which has an uncertainty of 0.5 MeV. The mass splitting is measured to be 10.60 0.64ðstatÞ 0.17ðsystÞ MeV.