KAI-FENG CHENPAO-TI CHANGRONG-SHYANG LUWEI-SHU HOU2021-07-282021-07-28202010298479https://www.scopus.com/inward/record.uri?eid=2-s2.0-85096395259&doi=10.1007%2fJHEP11%282020%29001&partnerID=40&md5=8c48a03175cf97cf23c7070f93df2c62https://scholars.lib.ntu.edu.tw/handle/123456789/573662The ratios of the production cross sections between the excited ?(2S) and ?(3S) mesons and the ?(1S) ground state, detected via their decay into two muons, are studied as a function of the number of charged particles in the event. The data are from proton-proton collisions at s = 7 TeV, corresponding to an integrated luminosity of 4.8 fb?1, collected with the CMS detector at the LHC. Evidence of a decrease in these ratios as a function of the particle multiplicity is observed, more pronounced at low transverse momentum pTμμ. For ?(nS) mesons with pTμμ> 7 GeV, where most of the data were collected, the correlation with multiplicity is studied as a function of the underlying event transverse sphericity and the number of particles in a cone around the ?(nS) direction. The ratios are found to be multiplicity independent for jet-like events. The mean pTμμ values for the ?(nS) states as a function of particle multiplicity are also measured and found to grow more steeply as their mass increases. [Figure not available: see fulltext.] ? 2020, The Author(s).journal article10.1007/JHEP11(2020)0012-s2.0-85096395259