EPJ Web of Conferences
Volume 81, 2014MESON 2014 – 13th International Workshop on Production, Properties and Interaction of Mesons
|Number of page(s)||4|
|Section||High energy hadron production - contributions|
|Published online||26 November 2014|
Quarkonium production and polarization in pp collisions with the CMS detector
University of Turin, INFN and CERN
a e-mail: email@example.com
Published online: 26 November 2014
Studies of the production of heavy quarkonium states are very important to improve our understanding of QCD and hadron formation, given that the heavy quark masses allow the application of theoretical tools less sensitive to nonperturbative effects. Thanks to a dedicated dimuon trigger strategy, combined with the record-level energy and luminosity provided by the LHC, the CMS experiment could collect large samples of pp collisions at 7 and 8 TeV, including quarkonium states decaying in the dimuon channel. This allowed the CMS collaboration to perform a series of systematic measurements in quarkonium production physics, including double-differential cross sections and polarizations, as a function of rapidity and pT, for five S-wave quarkonia: J/ψ, ψ (2S), ϒ(1S), ϒ(2S), and ϒ(3S). Some of these measurements extend well above pT ≃ 100 GeV, probing regions of very high pT/mass, where the theory calculations are supposed to be the most reliable. Thanks to its high-granularity silicon tracker, CMS can reconstruct lowenergy photons through their conversions to e+e− pairs, thereby accessing the radiative decays of the P-wave quarkonium states, with an extremely good mass resolution, so that the J=1 and J=2 1P states can be resolved. This allows CMS to determine cross-section ratios and feed-down decay fractions involving the χ states, in both the charmonium and bottomonium families.
This talk presents some of the most recent CMS quarkonium production results, in pp collisions, in particular the production of ϒ(1S,2S,3S), the cross-section ratio of charmonium and bottomonium P-wave states and the polarization of S-wave cc̄ and bb̄ states.
© Owned by the authors, published by EDP Sciences, 2014
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.