We report on measurements of charged pion production cross sections at θ ≅ 50°, p T ≅ 3–9 GeV / c and √ s = 45 GeV , taken with the Split Field Magnet Detector at the CERN Intersecting Storage Rings (ISR). Together with previous data at √ s = 62 GeV , this allows the calculation of the exponent n assuming a power law dependence p n T . Values of n ≈ 8 are found at low x T = 2 p T /√ s which drop to about 7 at x T ≈ 0.3. The measured values of π + /π − rise with x T and approach ≈ 2 at x T ≈ 0.3. A first-order QCD calculations is reasonably consistent with the data.
No description provided.
The ratios of high p T charged kaon to pion production cross sections at √ s = 45 and 62 GeV are presented. The values of the K ± π ± ratios are essentially independent of both √ s and x T = 2p T √s and are compatible with a strangeness suppression factor λ = 0.55. By contrast, the K − π − values fall with x T suggesting a gluonic origin of K − . QCD calculations agrees with the measurements.
No description provided.
No description provided.
The multiplicities of charged secondaries in proton-proton collisions were determined using the split-field-magnet detector at the CERN Intersecting Storage Rings (ISR). Measurements are presented on multiplicity distributions both for inelastic and non-single-diffractive events at four different energies s=30.4, 44.5, 52.6, and 62.2 GeV. The results reported here represent the first high-statistics measurement of charged multiplicity distributions at ISR energies with a magnetic detector covering nearly the full solid angle.
INELASTIC EVENTS.
NON-SINGLE-DIFFRACTIVE EVENTS.
Moments of the multiplicity distributions for Inelastic events.
Events with a single highpT charged particle were recorded with the Split-Field-Magnet Detector in proton-proton collisions at the CERN-ISR. In the jet opposite to the trigger region the densities of photons and reconstructed neutral pions were measured with a liquid argon shower counter. Scaled momentum distributions of these particles are given and compared with those of charged pions. The spectra of charged and neutral pions coincide. The production cross-section of neutrals in the away jet shows no dependence on the flavour of the trigger particle.
No description provided.
We present evidence for the existence of two strange J P = 1 − mesons; one at 1410 MeV/c 2 coupling principally to K ∗ (892)π , and the other at 1790 MeV/c 2 couplingto K π , K ∗ π and ϱ K. The data derive from a partial wave analysis of the K 0 π + π − system produced in the reaction K − p → K 0 π + π − n at 11 GeV /c . The production mechanism and quark model assignment of each state are discussed. The state at 1410 MeV/c 2 most naturally understood as the first radial excitation of the K ∗ (892), and the 1790 MeV/c 2 object can be interpreted as the triplet D wave partner to the 3 − K ∗ (1780).
No description provided.
We have measured the differential cross section for pp and p̄p elastic scattering at √ s = 31, 53 and 62 GeV in the interval 0.05 < | t | < 0.85 GeV 2 at the CERN ISR using the Split Field Magnet detector. At 53 and 62 GeV, for 0.17 < | t | < 0.85 GeV 2 both pp and p̄p data show simple exponential behaviour in t ; at √ s = 31 GeV the data for 0.05 < | t | < 0.85 GeV 2 are consistent with a change in slope near | t | = 0.15 GeV 2 .
ERRORS CONTAIN BOTH STATISTICAL AND T-DEPENDENT SYSYEMATIC ERRORS.
No description provided.
LOCAL SLOPE PARAMETERS BASED ON QUADRATIC EXPONENTIAL FIT.
We have measured the differential cross section for p¯p and pp elastic scattering at s=53 GeV in the interval 0.5<|t|<4.0 (GeV/c)2 at the CERN intersecting storage rings using the split-field magnet detector. The shape of the differential cross section differs significantly between p¯p and pp scattering in the region 1.1<|t|<1.5 (GeV/c)2, with p¯p data showing a less pronounced dip structure than pp data.
No description provided.
No description provided.
Large samples of inclusively produced Ξ−, Ω−, and Ξ0(1530) events are presented from a 1427 events/μb exposure of the large-aperture superconducting-solenoid spectrometer to an 11-GeV/c K− beam. Production characteristics of these states are compared with other data and shown to be consistent with hyperon exchange. Polarization of Ξ− shows an increase in magnitude with both Feynman x and transverse momentum. The Ξ− decay parameters are measured to be αΞ=-0.40±0.03 and ΦΞ=(5±10)° . Results of searches for higher-mass hyperons are presented. The Ξ−(1820)→Ξ0(1530)π− decay is observed, while we fail to confirm the existence of the Σ+(3170).
No description provided.
No description provided.
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The relative yields of kaons and protons compared with the yield of pions at highpT and polar angles θ away from 90° (in the range from 10° to 45°) are presented forpp, dd, and αα interactions at a centre-of-mass energy\(\sqrt {s_{NN} }= 31\) GeV per nucleon-nucleon collision. The measured particle ratios depend on the atomic mass numberA of the beam particles and on θ. TheA dependence of the ratios becomes stronger for largerpT and is more pronounced at smaller polar angles.
ERRORS ARE PURELY STATISTICAL.
ERRORS ARE PURELY STATISTICAL.
ERRORS ARE PURELY STATISTICAL.
Data are presented for the exclusive reaction pp → pp π+ π− at\(\sqrt s= 62GeV\) with two leading protons at large Feynman-x and a centrally produced π+;π− system. In this kinematical configuration one expects a substantial contribution from Double Pomeron Exchange, which is a potential source of glueballs. The experiment was performed at the CERN ISR using the Split Field Magnet spectrometer. In the mass range between 1,000 and 1,700 MeV/c2 the invariant mass distribution for the central π+;π− system exhibits a very significant signal for thef0(1270) and no other obvious resonant states.
No description provided.
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