Measurement of the $$\psi(2S)$$ Production Cross Section and Polarization at $$p\bar{p}$$ Collisions at $$\sqrt{s}$$ = 1.8-TeV

Thesis/Dissertation · Thu Feb 01 04:00:00 EST 2001

DOI:https://doi.org/10.2172/1369301· OSTI ID:1369301

Ngan, Ching-Yuk Paul ^[1]

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1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

We present a measurement of the polarization of $$\psi$$(2S) mesons produced in $$p\bar{p}$$ collisions at $$\sqrt{s}$$ = 1.8 TeV with the CDF detector at Fermilab. This measurement is a sensitive test of the calculations based on the Non-relativistic QCD (NRQCD) factorization mechanism, which are able to account for the unexpectedly large cross section for charmonium production in $$p\bar{p}$$ collisions (roughly a factor 50 above the Color Singlet Model). These calculations also predict that directly produced charmonia should approach 100% transverse polarization for high transverse momentum of the onium state. We consider $$\psi$$(2S) mesons, reconstructed using the decay mode $$\psi(2S) \to \mu^+\mu^-$$ in a 110 $$pb^{-1}$$ data sample of $$p\bar{p}$$ collisions. The polarization of prompt $$\psi$$(2S) is extracted to be -0.54 ± 0.48( stat.) ± 0.04(syst.) for 9 < $$P_T(\psi$$(2S)) < 20 GeV/c.

• Research Organization: Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
• DOE Contract Number: AC02-07CH11359
• OSTI ID: 1369301
• Report Number(s): FERMILAB-THESIS--2001-50; 580551
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS