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

M. Andreotti, S. Bagnasco, W. Baldini, D. Bettoni, G. Borreani, A. Buzzo, R. Calabrese, R. Cester, G. Cibinetto, P. Dalpiaz, G. Garzoglio, K. E. Gollwitzer, M. Graham, M. Hu, D. Joffe, J. Kasper, G. Lasio, M. Lo Vetere, E. Luppi, M. MacrìM. Mandelkern, F. Marchetto, M. Marinelli, E. Menichetti, Z. Metreveli, R. Mussa, M. Negrini, M. M. Obertino, M. Pallavicini, N. Pastrone, C. Patrignani, S. Pordes, E. Robutti, W. Roethel, J. Rosen, P. Rumerio, R. W. Rusack, A. Santroni, J. Schultz, S. H. Seo, K. K. Seth, G. Stancari*, M. Stancari, A. Tomaradze, I. Uman, T. Vidnovic, S. Werkema, P. Zweber

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

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.

Original languageEnglish (US)
Pages (from-to)74-79
Number of pages6
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume654
Issue number3-4
DOIs
StatePublished - Oct 11 2007

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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