Approximately 60 000 events have been collected in a spark chamber experiment at the CERN Proton Synchrotron which studied elastic diffraction scattering of π--p and p-p at incident momenta of 8.5, 12.4 and 18.4 GeV/c and of π+-p at 8.5 and 12.4 GeV/c. Magnetic analysis of the incoming and diffraction scattered particle, together with measurement of all angles, permitted each event to be determined as elastic subject to three constraints, so that the inelastic background was rejected with. high efficiency, even at the larger momentum, transfers. Much of the data have been processed by the CERN Automatic Flying-Spot DigitizerHPD. A detailed description of the experimental technique and of the methods of analysis is given. The results, together with data from lower energies, confirm the remarkable energy-independence of the shape of the pion-proton diffraction scattering peak up to |t| = 1.5 (GeV/c)2, wheret is the square of the four-momentum transfer, over a range of pion energies from 2 to 18 GeV. Proton-proton scattering does however appear to show a shrinking diffraction peak. In general, the data agree with other experiments using both counter and bubble chamber techniques, but some differences do appear. During the experiment, data were taken which set an upper limit of 2·102 μb/(GeV/c)2 on the differential elastic cross-section dσ/dt over a range of |t| from 20.9 to 23.4 (GeV/c)2 at 13.4 GeV/c incident pion momentum.
'1'. '2'. '3'. '4'.
'1'.
'1'.
The real part of the proton proton elastic scattering amplitude has been determined from its interference with the Coulomb amplitude at total centre-of-mass energies up to 62 GeV. The observed steady increase of ϱ with energy indicates that the total proton proton cross section continues to increase well beyond this energy.
No description provided.
USING SIG AND SLOPE OBTAINED FROM INTERPOLATIONS OF PREVIOUS MEASUREMENTS.
Λp interactions have been studied at momenta up to 24 GeV/ c using a new bubble chamber technique. We find that the Λp elastic cross section has fallen to approximately 6 mb at the highest momentum. Results are presented on Λ p→ Λ p π + π − for the first time above 5 GeV c .
No description provided.
No description provided.
ESTIMATE.
The reaction π − + p → π − + π − + π + + p at 25 GeV/ c was studied in the mass region M 3 π ⩾ 1.8 GeV with leading π + . The mass spectrum of the π + π − system shows peaks corresponding to the ϱ 0 , f and g 0 resonances and an enhancement around 1.9 GeV. Evidence is presented for a J P = 3 + s-wave g 0 π − state (A 4 ) similar to the ϱ 0 π − (A 1 ) and fπ − (A 3 ) threshold enhancements.
No description provided.
None
FOUR PION RESONANCE CALLED RHO(1.71) BY AUTHORS. DECAY IS CONSISTENT WITH 100 PCT <RHO0 RHO-> MODE.
From an experiment done with the CERN Omega spectrometer, triggered by a fast forward proton device, we present results on the differential cross section d σ d u for π − p backward elastic scattering. The d σ d u distribution agrees with an A e Bu law. The compilation of existing results shows a discrepancy between results but the ( d σ d u ) u=0 data fit perfectly an s 2 α 0 −2 dependence, as predicted by a single Δδ Regge trajectory exchange. A search for the reaction π − p → d p , with a fast forward deuteron, which can be produced by a double-baryon exchange mechanism, gives cross-section upper limits of ∼1% of the backward elastic cross section.
UMIN IS 0.0446 GEV**2.
UMIN IS 0.0333 GEV**2.
D(SIG)/DU FITTED FOR 0 < -U < 0.75 GEV**2 TO GIVE SLOPE/INTERCEPT.
Single and joint decay angular distributions in the reaction p p → Δ ++ Δ ++ at 9.13 GeV/ c are discussed in the framework of single and double statistical tensors. The t dependence of 12 double statistical tensors is presented. Cross sections for p p → p p π + π − and p p → Δ ++ Δ ++ are determined to be 2.60 ± 0.10 and 0.90 ± 0.10 mb respectively. The results obtained are compared with other experiments mainly at 5.7 and 12 GeV/ c .
No description provided.
No description provided.
FROM FITTING DECAY ANGULAR DISTRIBUTIONS OF BOTH ISOBARS ADDED.
The ratio of π+p to pp elastic scattering is found to be smoothly varying over the range −t=0.03 to 0.4 GeV2. It is well fitted by a single exponential, indicating the forward behavior must be quite similar for the two reactions.
ACTUALLY THE DATA ARE THE EXPONENTIAL SLOPE OF THE RATIO OF D(SIG)/DT FOR THE TWO REACTIONS.
The photoproduction of the ψ(3100) meson from a beryllium target has been measured using an 11.8-GeV bremsstrahlung beam. The energy and angular dependence of the measured spectra may be obtained from an elastic nucleon cross section of the form dσdt=(1.01±0.20)exp[(1.25±0.20)t] nb/GeV2. This cross section is exceedingly small in comparison with those of the other vector mesons.
ELECTRON PAIR PRODUCTION FROM BERYLLIUM TARGET. ELASTIC CROSS SECTION VALUE ALLOWS FOR SYSTEMATIC UNCERTAINTIES AND POSSIBLE INELASTIC CONTRIBUTIONS. -TMIN = 0.41 GEV**2.
Results are presented for the reactions (1) π+n→pπ+π−, (2) π+n→pπ+π−π0, at an incident pion beam momentum of 11.7 GeV/c. Both reactions show considerable resonance production. Reaction (1) is dominated by ρ0 and f0 production and there is evidence for the variation of the ρ00 width with momentum transfer. Decay angular distributions are presented for the dipion system observed in reaction (1). Reaction (2) shows the production of both dipion and tripion resonances and there is evidence for the associated production of\(\mathcal{N}\)-resonances with the dipion resonances.
No description provided.
DN/DT PLOTTED. ALL RESONANCES ARE DEFINED JUST BY MASS CUTS.
RHO0 MASS REGION OF DIPION SYSTEM. NUMERICAL VALUES TAKEN FROM TABLE 6.1 OF THE THESIS BY D. KEMP (DURHAM 1974).