Precision measurements of the total and partial widths of the psi(2S) charmonium meson with a new complementary-scan technique in (p)over-barp annihilations

We present new precision measurements of the psi (2S) total and partial widths from excitation curves obtained in antiproton-proton annihilations by Fermilab experiment E835 at the Antiproton Accumulator in the year 2000. A new technique of complementary scans was developed to study narrow resonances with stochastically cooled antiproton beams. The technique relies on precise revolution-frequency and orbit-length measurements. while making the analysis of the excitation curve almost independent of machine lattice parameters. We study the psi (2S) meson through the processes pp -> e(+)e(-) and pp -> J/psi + X -> e(+)e(-) + X. We measure the width to be Gamma = 290 +/- 25(sta) +/- 4(sys) keV and the combination of partial widths Gamma(+)(-)(e)(e) - Gamma pp/Gamma = 579 +/- 38(sta) +/- 36(sys) meV, which represent the most precise measurements to date. (C) 2007 Elsevier B.V. All rights reserved.