1. Precision measurements of the total and partial widths of the ψ (2 S) charmonium meson with a new complementary-scan technique in over(p, ̄) p annihilations
- Author
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Andreotti, M, Bagnasco, S, Baldini, W, Bettoni, D, Borreani, G, Buzzo, A, Calabrese, R, Cester, R, Cibinetto, G, Dalpiaz, P, Garzoglio, G, Gollwitzer, KE, Graham, M, Hu, M, Joffe, D, Kasper, J, Lasio, G, Lo Vetere, M, Luppi, E, Macrì, M, Mandelkern, M, Marchetto, F, Marinelli, M, Menichetti, E, Metreveli, Z, Mussa, R, Negrini, M, Obertino, MM, Pallavicini, M, Pastrone, N, Patrignani, C, Pordes, S, Robutti, E, Roethel, W, Rosen, J, Rumerio, P, Rusack, RW, Santroni, A, Schultz, J, Seo, SH, Seth, KK, Stancari, G, Stancari, M, Tomaradze, A, Uman, I, Vidnovic, T, Werkema, S, and Zweber, P
- Subjects
Nuclear & Particles Physics ,Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Astronomical and Space Sciences ,Mathematical Physics ,Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics - Abstract
We present new precision measurements of the ψ (2 S) 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 ψ (2 S) meson through the processes over(p, ̄) p → e+ e- and over(p, ̄) p → J / ψ + X → e+ e- + X. We measure the width to be Γ = 290 ± 25 (sta) ± 4 (sys) keV and the combination of partial widths Γe+ e- Γover(p, ̄) p / Γ = 579 ± 38 (sta) ± 36 (sys) meV, which represent the most precise measurements to date. © 2007 Elsevier B.V. All rights reserved.
- Published
- 2007