Measurement of the resonance parameters of the charmonium ground state, ηc(11 S0)

M. Ambrogiani, M. Andreotti, S. Argirò, S. Bagnasco, W. Baldini, D. Bettoni, G. Borreani, A. Buzzo, R. Calabrese, R. Cester, G. Cibinetto, P. Dalpiaz, X. Fan, G. Garzoglio, K. E. Gollwitzer, M. Graham, A. Hahn, S. Jin, D. Joffe, J. KasperG. Lasio, M. Lo Vetere, E. Luppi, P. Maas, M. Macrí, M. Mandelkern, F. Marchetto, M. Marinelli, W. Marsh, M. Martini, E. Menichetti, Z. Metreveli, R. Mussa, M. Negrini, M. M. Obertino, M. Pallavicini, N. Pastrone, C. Patrignani, T. K. Pedlar, J. Peoples, S. Pordes, E. Robutti, W. Roethel, J. Rosen, P. Rumerio, R. Rusack, A. Santroni, M. Savriè, J. Schultz, S. H. Seo, K. K. Seth*, G. Stancari, M. Stancari, J. Streets, A. Tomaradze, I. Uman, T. Vidnovic, S. Werkema, G. Zioulas

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


The resonance parameters of the charmonium ground state, ηc(11S0), have been measured by means of the reaction p̄p→ηc→γγ. The mass and total width are determined to be 2984.1 ± 2.1 ± 1.0 MeV/c2 and 20.4-6.7+7.7 ± 2.0 MeV, respectively. The product of branching ratios B(p̄p→ηc)B(ηc→γγ) is determined to be (22.4-3.7+3.8 ± 2.0) × 10-8, from which B(ηc→γγ)=(1.87-0.31-0.50 +0.32+0.95) × 10-4, and Γ(ηc→γγ)=3.8-1.0-1.0 +1.1+1.9 keV are derived using B(ηc→p̄p)= (12 ± 4) × 10-4 from the literature.

Original languageEnglish (US)
Pages (from-to)45-50
Number of pages6
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Issue number1-2
StatePublished - Jul 24 2003

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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