Study of the angular distributions of the reactions p̄p→χc1, χc2→J/ψγ→e+e-γ

M. Ambrogiani*, S. Bagnasco, W. Baldini, D. Bettoni, G. Borreani, A. Buzzo, R. Calabrese, R. Cester, P. Dalpiaz, X. Fan, G. Garzoglio, K. Gollwitzer, A. Hahn, S. Jin, J. Kasper, G. Lasio, M. LoVetere, E. Luppi, P. Maas, M. MacrìM. Mandelkern, F. Marchetto, M. Marinelli, E. Menichetti, R. Mussa, M. Obertino, M. Pallavicini, N. Pastrone, C. Patrignani, T. Pedlar, S. Pordes, E. Robutti, J. Rosen, P. Rumerio, A. Santroni, M. Savrié, J. Schultz, K. K. Seth, G. Stancari, M. Stancari, J. Streets, A. Tomaradze, S. Werkema, G. Zioulas

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

40 Scopus citations


We report on a study of the angular distributions in the radiative decay of the Xc1 and Xc2 states formed in p̄p annihilations. These distributions depend on the dynamics of the formation process and the multipole structure of the radiative decay. Using 2090 Xc1 and 5908 Xc2 events, we have measured the fractional magnetic quadrupole and amplitude to be a2(Xc1)-M 2/E1 ≃ 0.002±0.032, a2(Xc2) = -0.093-0.041+0.039. We have also measured the square of the helicity 0 fractional amplitude in the Xc2 formation process to be B02 =0.13 ±0.08.

Original languageEnglish (US)
Article number052002
Pages (from-to)520021-5200210
Number of pages4680190
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number5
StatePublished - Mar 1 2002

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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