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We present an analysis, in the framework of the triple Regge model, of our recent experimental results on the reaction p+p→p+X between 50 and 400 GeV.
The cross sections is fitted in the framework of the triple Regge model. The symbols P and R in the (C=...) denote pomeron and reggeon, respectively. For fit I and II the authors used conventional trajectories alpha(P) = 1 +0.25*T, alpha(R) = 0.5 + T. Fit II is restricted to data with (1 - M(P=4)**2/S) > 0.84. In fit III they use alpha(R) = 0.2 + T for the RRP term. Fit IV is like fit I with additional fixed (pion pion P) term.
The cross sections is fitted in the farmework of the triple Regge model. The symbols P and R in teh (C=...) denote pomeron and reggeon, respectively. CONST(C=C) and SLOPE are from the replacement of the RRP term by the exponential one : CONST(C=C)*(SLOPE*(1-x)). See text for detail.
The π − p→n γ and π − p→n π ° differential cross sections have been measured for −0.9< cos θ ∗ <−0.45 (θ ∗ c.m. scattering angle) at 475 MeV/ c and 550 MeV/ c incident momenta. The π − p→n γ measurement is a good check of the detailed balance principle in the electromagnetic interactions of hadrons at these energies and is in good agreement with Walker's analysis. On the other hand the π − p→ π °n extrapolated values of 180° allows one to verify that the phases of the A 1 2 and A 3 2 amplitudes are equal.
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BACKWARD CROSS SECTION ESTIMATED BY LEGENDRE POLYNOMIAL FIT.
The reaction e − + p → e − + p + η has been studied in the region of the S 11 (1535)-resonance by detecting the recoil proton in coincidence with the scattered electron. The reaction has been observed at three four-momentum transfers of the virtual photon: q 2 = 0.2, 0.28 and 0.4 (GeV/ c ). First results of the differential cross section measurements are given and compared with quark model calculations.
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We have measured elastic pion-proton scattering in a 50 GeV/ c π − beam at the 76 GeV proton synchrotron in Serpukhov. Data are presented for four-momenta transfer squared in the range 0.03 < t < 0.4 (GeV/ c ) 2 .
SLOPE IS 9.1, +0.2, -0.4 GEV**-2 (INCLUDING SYSTEMATIC ERRORS).
Data have been taken at the φ energy with the same large solid angle detector which has been used for the measurement of the ϱ and ω production by e + e − annihilations. From the φ → K o L K o S π + φ − excitation curve we have deduced the φ width Γ φ = (3.81 ± 0.37) MeV and the cross-section σ e + e − → K o L K o S = (1.48±0.08±0.12) μ b. (the quoted errors are respectively statistical and systematical.)
EXPERIMENTAL CROSS SECTION INCLUDING RADIATIVE EFFECTS.
FITTED CROSS SECTION AT PHI PEAK, RADIATIVELY CORRECTED.
K + p elastic scattering has been measured over nearly the whole angular range at an incident momentum of 10 GeV/ c . The differential cross-section is found to decrease smoothly in the forward direction to - t ≈ 2 (GeV/ c ) 2 , where there is a change in slope, followed by a further decrease to - t ≈ 6 (GeV/ c ) 2 . Around 90° c.m. the cross-section is approximately 1 nb/(GeV/ c ) 2 , which is more than two orders of magnitude lower than at 5 GeV/ c . The backward peak has no structure.
THESE DATA ARE REPORTED MORE FULLY IN C. BAGLIN ET AL., NP B98, 365 (1975).
A large solid angle detector has been used to observe π + π − π o events produced at the φ energy by electron-positron collisions in the Orsay storage ring. Fitting our data with a Breit and Wigner curve, with a fixed width Γ = (3.8±0.4) MeV coming from K O S K O L analysis, we deduce σ e + e − → π + π − π O = (0.70±0.13) μ bat 2 E = Mφ . Using our measurements on the other φ decay modes we deduce ( φ → π + π − π o )/( φ → K o S K o L ) = 0.47±0.06 and ( φ → η o γ )/( φ → K o S K o L ) = 0.077±0.022. Assuming ( φ → K + K − )/( φ → K o S K o L ) = 1.60, we derive σ TOT = (4.7±0.4) μ b, Γ e + e − = (1.27±0.11 keV and g 2 o /4 π = 14.3±1.3 (without finite width correction). Furthermore (from the observation of the ππγ coplanar events) we put an upper limit to the mode e + e − → φ π + π − γ , Γ ( φ → π + π − γ ) ⩽ 0.007 Γ ( φ → Total ) with 90% C.L.
EXPERIMENTAL CROSS SECTIONS INCLUDING RADIATIVE EFFECTS.
FITTED PARTIAL AND TOTAL CROSS SECTION AT PHI PEAK, RADIATIVELY CORRECTED.
The angular distribution of π + p elastic scattering has been measured at an incident momentum of 10 GeV/ c . Nearly the whole angular range was covered in one experimental set-up. The pronounced dip at − t = 2.8 (GeV/ c ) 2 , observed at lower momenta, has diminished and is essentially a shoulder at 10 GeV/ c . The other structure at larger momentum transfers are also different in detail from what we observed at 5 GeV/ c . In the 90° c.m. region the differential cross-section is approximately one nb/(GeV/ c ) 2 , which is more than two orders of magnitude lower than at 5 GeV/ c .
THESE DATA ARE REPORTED MORE FULLY IN C. BAGLIN ET AL., NP B98, 365 (1975).
Results are reported of a study of the hypercharge reactions K − p → ωΛ (la), K − p → φΛ (lb), K − p → φ ∑ o (lc), K − p → ϱ o Λ (ld), K − p → ϱ o ∑ o (le), K − p → ϱ − ∑ + (lf) in a 12 events/ub bubble chamber experiment using K − mesons of 4.25 GeV/ c momentum. Total and differential cross sections are presented as well as the density matrix elements of the peripherally produced vector meson and (except for reaction (1f)) the hyperon polarization. For reactions (1a) and (1b) an amplitude analysis is performed. The mass and the width of the ϱ−, φ− and f-meson have been determined.
FURTHER DATA FROM THIS COLLABORATION ON THESE REACTIONS WITH TEN TIMES BETTER STATISTICS ARE PRESENTED IN M. J. LOSTY ET AL., NP B133, 38 (1978).
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