Hadroproduction of the Chi1 and Chi2 States of Charmonium in 800 GeV/c
  Proton-Silicon Interactions

A. Blankman; A. Boden; A. Ledovskoy; A. P. McManus; A. R. Erwin; B. Cox; B. T. Zou; C. Durandet; C. R. Wang; C. T. Murphy; C. Wei; D. Cline; D. E. Wagoner; D. Judd; E. C. Dukes; E. Gorini; F. Grancagnolo; G. Bonomi; G. Corti; G. H. Mo; G. Introzzi; G. Liguori; H. Bingham; H. C. Ballagh; J. G. Sun; J. Lys; J. Rhoades; J. Trischuk; K. Clark; K. Hagan; K. Lau; K. Nelson; L. Antoniazzi; L. Fortney; L. Spiegel; L. Turnbull; M. Arenton; M. Block; M. Cooper; M. Haire; M. He; M. Jenkins; N. J. Zhang; N. Yao; P. Creti; P. Hanlet; P. O. Mazur; P. Torre; R. P. Smith; S. Conetti; S. Misawa; S. Ramachandran; S. Tokar; T. Alexopoulos; T. Y. Chen; V. Elia; V. Golovatyuk; V. Pogosyan; W. Kononenko; W. Kowald; W. Selove; W. Yang; Z. L. Cao

research

Hadroproduction of the Chi1 and Chi2 States of Charmonium in 800 GeV/c Proton-Silicon Interactions

Abstract

The cross sections for the hadroproduction of the Chi1 and Chi2 states of charmonium in proton-silicon collisions at sqrt{s}=38.8 GeV have been measured in Fermilab fixed target Experiment 771. The Chi states were observed via their radiative decay to J/psi+gamma, where the photon converted to e+e- in the material of the spectrometer. The measured values for the Chi1 and Chi2 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(Chi1}/sigma(Chi2) ratio of 0.53+-0.20(stat)+-0.07(syst), although somewhat larger than most theoretical expectations, can be accomodated by the latest theoretical estimates.Comment: 4 pages, 4 figure