Total and differential cross sections are presented on the reactions: p ̄ p → Λ Λ, ΛΣ 0 + c.c. , Σ + Σ + at an incident momentum of 5.7 GeV/ c , from 200 000 photographs (13 events/ Σ b) of the CERN 2 metre hydrogen bubble chamber. The “forbidden” reaction p ̄ p → Σ − Σ − is also observed and its cross section is 1.3 ± 0.4 μ b. Polarization and correlation of polarizations are presented for the reaction p ̄ p → Λ Λ .
No description provided.
The reaction e + e − → ω o has been measured by detecting the charged pions of the π + π − π o decay mode of the ω o. A partial decay width of ω o in e + e − : Γ e + e − =0.94±0.18 keV is deduced from this result.
FITTED, BACKGROUND SUBTRACTED, PEAK OMEGA CROSS SECTION, CORRECTED FOR UNOBSERVED DECAYS, IS 1.82 +- 0.34 MUB. TABULATED ASSUMING CENTRAL ENERGY IS 782.6 MEV. VACUUM POLARIZATION AND RADIATIVE CORRECTIONS APPLIED.
The electromagnetic form factor of the pion has been determined in the ϱ o resonance region by measuring the absolute cross section of the reaction e + e − → π + π − with the Orsay storage ring. More than 800 pion pairs have been detected. The excitation curve has been fitted with a Breit-Wigner formula which leads to the following values: σ peak = (1.69 ± 0.21) 10 −30 cm 2 ; m ϱ = (770 ± 4) MeV ; Γ ϱ = (111 ± 6) MeV . The partial width of the ϱ o going into e + e − thus obtained is: Γ ϱ → e + e − =(7.36±0.7) keV .
No description provided.
Inelastic electron proton scattering has been measured by detecting the scattered electron, thus obtaining the total absorption cross section for virtual photons. Two complete spectra from threshold to a pion nucleon mass of W = 2 GeV were taken at θ e = 48.3° and fixed primary energies of 3.963 GeV and 5.159 GeV, respectively, corresponding to a momentum transfer at the first resonance of q 2 = 3.98 (GeV/ c ) 2 and q 2 = 5.84 (GeV/ c ) 2 . In addition, a measurement at θ e = 47.9° and at a primary energy of 3.306 GeV in the region of the first resonance is reported.
No description provided.
None
Only statistical errors are given.
Only statistical errors are given.
None
RELATIVE PRODUCTION OF PION PAIRS WITHOUT RADIATIVE CORRECTIONS.
The cross section for photoproduction of π0 mesons was measured at a photon energy of 3 GeV and squared four-momentum transfer (t) of -0.1 to -1.2 (GeV/c)2 using plane-polarized photons. The asymmetry was found to be consistent with +1.0 for t values above -0.4 and below -1.1. For −0.4<~t<~−1.0 there is a dip in the asymmetry and at t=−0.6 it drops to 0.55 ± 0.15. This result precludes a simple Regge model with ω0 and B; a theoretical description requires Regge cuts or an ω′ exchange.
No description provided.
MIT PREP (1967).
Differential cross sections for the elastic scattering of negative pions from hydrogen have been measured over a limited range of squared four-momentum transfer (t) in the vicinity of t≃−3 (GeV/c)2 for incident pion momenta of 2.51, 2.76, and 3.01 GeV/c. These measurements confirm the existence of a minimum in the differential cross section in this region of incident momentum and scattering angle. The minimum occurs at a smaller value of t [t≃−2.6 (GeV/c)2] than has been observed at higher momenta.
No description provided.
No description provided.
No description provided.
The differential cross sections for the elastic scattering of negative pions by deuterons have been measured for 2.01-, 3.77-, and 5.53-GeV/c incident pion momenta, over an interval of the squared four-momentum transfer from -0.25 (GeV/c)2 to ∼-1.0 (GeV/c)2. The results are consistent with calculations based on a Glauber model of the scattering process.
No description provided.
No description provided.
No description provided.
The external beam of the 2.5 GeV-electron-synchrotron has been used to measre elastic electron proton scattering at four-momentum-transfers between 15 and 50 fm<sup loc="post">−2</sup>. By combining these results with measurements at small angles at DESY, we have obtained the electric and magnetic form factors separately. Their ratio shows a deviation from the scaling law.
No description provided.
No description provided.