Hadroproduction of the chi(1) and chi(2) states of charmonium in 800-GeV/cproton-silicon interactions - art. no. 032006

Alexopoulos, T Antoniazzi, L Arenton, M Ballagh, HC Bingham, H Blankman, A Block, M Boden, A Bonomi, G Cao, ZL Chen, TY Clark, K Cline, D Conetti, S Cooper, M Corti, G Cox, B Creti, P Dukes, EC Durandet, C Elia, V Erwin, AR Fortney, L Golovatyuk, V Gorini, E Grancagnolo, F Hagan, K Haire, M Hanlet, P He, M Introzzi, G Jenkins, M Judd, D Kononenko, W Kowald, W Lau, K Ledovskoy, A Liguori, G Lys, J Mazur, PO McManus, AP Misawa, S Mo, GH Murphy, CT Nelson, K Pogosyan, V Ramachandran, S Rhoades, J Selove, W Smith, RP Spiegel, L Sun, JG Tokar, S Torre, P Trischuk, J Turnbull, L Wagoner, DE Wang, CR Wei, C Yang, W Yao, N Zhang, NJ Zou, BT

T. Alexopoulos et al., Hadroproduction of the chi(1) and chi(2) states of charmonium in 800-GeV/cproton-silicon interactions - art. no. 032006, PHYS REV D, 6203(3), 2000, pp. 2006

23

INGLESE

Article

Physics

PHYSICAL REVIEW D

0556-2821 → ACNP

6203

3

2000

ISI

0556-2821(20000801)6203:3<2006:HOTCAC>2.0.ZU;2-8

The cross sections for the hadroproduction of the chi(1) and chi(2) states of charmonium in proton-silicon collisions at root s = 38.8 GeV have been m easured in Fermilab fixed target experiment 771. The chi states were observ ed via their radiative decay to J/psi gamma, where the photon converted to e(+)e(-) i(n) the material of the spectrometer. The estimated values for th e chi(1) and chi(2) cross sections for x(F) > 0 are 263 +/- 69(stat) +/- 32 (syst) and 498 +/- 143(stat) +/- 67(syst) nb per nucleon, respectively. The resulting sigma(chi(1))/sigma(chi(2)) ratio of 0.53 +/- 0.20(stat) +/- 0.0 7( syst), although somewhat larger than most theoretical expectations, can be accommodated by the latest theoretical estimates.