학술논문
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
Document Type
article
Author
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; Zweber, P
Source
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. 654(3-4)
Subject
Language
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.