Feasibility study of a J/$\psi$ cross section measurement with early CMS data

CMS Physics Analysis Summaries
Report number	CMS-PAS-BPH-07-002
Title	Feasibility study of a J/$\psi$ cross section measurement with early CMS data
Corporate author(s)	CMS Collaboration
Collaboration	CMS Collaboration
Imprint	2009/07/29
Subject category	Particle Physics - Experiment
Accelerator/Facility, Experiment	CERN LHC ; CMS
Abstract	We report on the methods and plans for measuring the differential $p_T$~ \jpsi$\rightarrow\mu^+\mu^-$ production cross section, using data to be collected in the first LHC run by the CMS detector. Making use of the large B-hadron lifetime, we show how to separate the promptly produced \jpsi's from those coming from B-hadron decays. Since the \jpsi~production cross section is expected to be large, the analysis should be viable with relatively small data sets, that will become available early in the startup of the LHC. We also address effects of a non-perfect detector alignment, as well as systematic uncertainties. About 70 thousand \jpsi~decays are reconstructed for an integrated luminosity of 3~pb$^{-1}$ in 14 TeV collisions, in the range of \ptjpsi~between 5 and 40 GeV/c. The precision of the result is limited by systematic uncertainties, and is at the 15~\% level.
Other source	Inspire
Email contact: [email protected] Fulltext in PDF Figure_001-a Figure_001-b Figure_002 Figure_003 Figure_004 Figure_005-a Figure_005-b Figure_006 Additional information for the analysis (restricted access)