Results of a search for the hc(P11) state of charmonium in the ηcγ and J/ψπ0 decay modes

M. Andreotti*, S. Bagnasco, W. Baldini, D. Bettoni, G. Borreani, A. Buzzo, R. Calabrese, R. Cester, G. Cibinetto, P. Dalpiaz, G. Garzoglio, K. E. Gollwitzer, M. Graham, M. Hu, D. Joffe, J. Kasper, G. Lasio, M. Lo Vetere, E. Luppi, M. MacrìM. Mandelkern, F. Marchetto, M. Marinelli, E. Menichetti, Z. Metreveli, R. Mussa, M. Negrini, M. M. Obertino, M. Pallavicini, N. Pastrone, C. Patrignani, T. K. Pedlar, S. Pordes, E. Robutti, W. Roethel, J. L. Rosen, P. Rumerio, R. Rusack, A. Santroni, J. Schultz, S. H. Seo, K. K. Seth, G. Stancari, M. Stancari, A. Tomaradze, I. Uman, T. Vidnovic, S. Werkema, P. Zweber

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

89 Scopus citations


We report evidence for the hc state of charmonium in its ηcγ decay mode and lack of evidence in the J/ψπ0 mode. We studied these channels in p̄p annihilations near the center of gravity of the PJ3 states, where the hc was reported in the J/ψπ0 mode by E760, our previous experiment, at 3526.2±0.15±0.2MeV, with ΓR≤1MeV. We observe an event excess in the ηcγ mode near 3526 MeV. Testing the null hypothesis of a linearly varying background cross section against the alternate hypothesis that includes a resonance near 3526 MeV, we reject the null hypothesis with P∼0.001. The resonance mass is 3525.8±0.2±0. 2MeV and the resonance width ≤1MeV. We estimate 10.0±3. 5<Γp̄pBηcγ<12.0±4.5eV, corresponding to fixed values 0.5<ΓR<1.0MeV. We find no event excess within the search region in the J/ψπ0 mode.

Original languageEnglish (US)
Article number032001
Pages (from-to)1-11
Number of pages11
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number3
StatePublished - Aug 1 2005

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)


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