Date

Study of narrow mesons near their thresholds

Binnie, D.M. ; Camilleri, L. ; Debenham, N.C. ; et al.
Phys.Rev.D 8 (1973) 2789-2813, 1973.
Inspire Record 93328 DOI 10.17182/hepdata.47579

A novel form of mass spectrometer has been used to measure the masses, widths, and cross sections of the η, ω, X0(958), and φ mesons near their respective thresholds in the reaction π−+p→missingmass+n. The incident momentum is varied in small steps through the threshold while neutrons of a given momentum are detected near zero degrees. The lower limit of the c.m. momentum P* at which measurements have been made ranges from about 50 MeV/c at the φ to about 30 MeV/c at the η. A somewhat low value for the ω mass, 782.3 ± 0.6 MeV, is found. The width of the X0 is < 1.9 MeV (95% confidence level). All four mesons show evidence of S-wave production, with values of σP* of 21.2 ± 1.8, 0.35 ± 0.03, and 0.29 ± 0.06 μb/(MeV/c) for the η, X0, and φ, respectively. A rapid rise in the ω cross section appears to be modified by a final-state interaction. The effect of this rise can probably be seen in some S11 pion-nucleon phase-shift solutions. Evidence is also presented of a sudden drop in the π+π− mass spectrum just above the threshold for the production of a K+K− pair. The paper includes a comprehensive discussion of the method and of the details of the spectrometer.

1 data table

CROSS SECTIONS NEAR THRESHOLD.


The charge exchange anti-p p ---> anti-n n at 5.0 and 7.76 gev/c near the forward direction

Lee, J.G. ; Harckham, A. ; Letheren, M. ; et al.
Nucl.Phys.B 52 (1973) 292-300, 1973.
Inspire Record 84235 DOI 10.17182/hepdata.32683

The differential cross section for the charge exchange p p → n n has been measured with high statistics at 7.76 GeV/ c and at 5.0 GeV/ c . The 7.76 GeV/ c data show a very narrow [ Δt ⪅ 0.01 (GeV/ c ) 2 ] forward peak superposed on a slow exponential fall-off.

3 data tables

No description provided.

No description provided.

INTEGRATED CROSS SECTIONS FROM EXPONENTIAL FIT.