The E760 Collaboration performed an experiment in the Antiproton Accumulator at Fermilab to study the two photon decay of the eta(c)(1(1)S(0)) charmonium state formed in ($) over bar pp annihilations. This resulted in a new measurement of the mass M(eta c) = 2988.3(-3.1)(+3.3) MeV/c(2) and of the product B(eta(c) --> ($) over bar pp) x Gamma(eta(c) --> gamma gamma) = (8.1(-2.0)(+22.9)) eV. We performed a search for the process ($) over bar pp --> eta(c)'(2(1)S(0)) --> gamma gamma over a limited range of center-of-mass energies. Since no signal was observed, we derived upper limits on the product of branching ratios B(eta(c)' --> ($) over bar pp) x B(eta(c)' --> gamma gamma) in the center-of-mass energy range 3584 less than or equal to root s less than or equal to 3624 MeV. We observed no signal for the nonresonant process ($) over bar p + p --> gamma + gamma and obtain upper limits.

STUDY OF THE ETA(C)(1 S-1(O)) STATE OF CHARMONIUM FORMED IN PP ANNIHILATIONS AND A SEARCH FOR THE ETA'(C)(2 S-1(O))

CALABRESE, Roberto;DALPIAZ, Pietro;LUPPI, Eleonora;PETRUCCI, Ferruccio Carlo;SAVRIE', Mauro;
1995

Abstract

The E760 Collaboration performed an experiment in the Antiproton Accumulator at Fermilab to study the two photon decay of the eta(c)(1(1)S(0)) charmonium state formed in ($) over bar pp annihilations. This resulted in a new measurement of the mass M(eta c) = 2988.3(-3.1)(+3.3) MeV/c(2) and of the product B(eta(c) --> ($) over bar pp) x Gamma(eta(c) --> gamma gamma) = (8.1(-2.0)(+22.9)) eV. We performed a search for the process ($) over bar pp --> eta(c)'(2(1)S(0)) --> gamma gamma over a limited range of center-of-mass energies. Since no signal was observed, we derived upper limits on the product of branching ratios B(eta(c)' --> ($) over bar pp) x B(eta(c)' --> gamma gamma) in the center-of-mass energy range 3584 less than or equal to root s less than or equal to 3624 MeV. We observed no signal for the nonresonant process ($) over bar p + p --> gamma + gamma and obtain upper limits.
1995
Armstrong, Ta; Bettoni, D; Bharadwaj, V; Biino, C; Blanford, G; Borreani, G; Broemmelsiek, D; Buzzo, A; Calabrese, Roberto; Ceccucci, A; Cester, R; Church, M; Dalpiaz, Pietro; P., FERRETTI DALPIAZ; Dimitroyannis, D; Fabbri, M; Fast, J; Gianoli, A; Ginsburg, Cm; Gollwitzer, K; Govi, G; Hahn, A; Hasan, M; Hsueh, S; Lewis, R; Luppi, Eleonora; Macri, M; Majewska, Am; Mandelkern, M; Marchetto, F; Marinelli, M; Marques, Kj; Marsh, W; Martini, M; Masuzawa, M; Menichetti, E; Migliori, A; Mussa, R; Palestini, S; Pallavicini, M; Passaggio, S; Pastrone, N; Patrignani, C; Peoples, J; Petrucci, Ferruccio Carlo; Pia, Mg; Pordes, S; Rapidis, P; Ray, R; Reid, J; Rinaudo, G; Roccuzzo, B; Rosen, J; Santroni, A; Sarmiento, M; Savrie', Mauro; Schultz, J; Seth, Kk; Smith, A; Smith, Ga; Sozzi, M; Trokenheim, S; Weber, Mf; Werkema, S; Zhang, Y; Zhao, J; Zioulas, G.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/516527
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