Inelastic differential cross sections have been measured for π±p, K±p, and p±p at 140- and 175-GeV/c incident momentum over a |t| range from 0.05 to 0.6 GeV2 and covering a missing-mass region from 2.4 to 9 GeV2. For Mx2 greater than 4 GeV2, the invariant quantity Mx2d2σdtdMx2 was found to be independent of Mx2 at fixed t and could be adequately described by a simple triple-Pomeron form. The values obtained for the triple-Pomeron couplings are identical within statistics for all channels.
Data from 140 GeV and 175 GeV are combined. The distributions are fit to CONST*(SLOPE(C=1)*T+SLOPE(C=2)*T**2).
Differential cross sections for K − n → Σ o π o have been measured at K − momenta between 680 and 840 MeV/ c in a bubble chamber experiment. For K − n → Σ o π − the Σ o polarization was also determined. The measurements were combined with the available data on K − p → Σπ in an energy-dependent partial wave analysis in the center of mass energy range from 1520 to 1745 MeV. An acceptable fit was obtained with the well established resonances.
FULL DETAILS OF THIS EXPERIMENT ARE IN V. HEPP ET AL., NP B115, 82 (1976), THE RECORD OF WHICH CONTAINS THE TABULATED TOTAL AND DIFFERENTIAL CROSS SECTIONS, POLARIZATIONS AND LEGENDRE POLYNOMIAL COEFFICIENTS.
Analyzing a sample of 220 000 events from an experiment still in progress at the CERN Proton Synchrotron (PS), 60 pairs of electrons with an energy above 700 MeV have been observed. The electrons, produced by annihilation of antiprotons stopped in a liquid-hydrogen target, are detected with optical spark chambers and scintillation counters. Twenty-nine out of these 60 pairs have been found to be collinear; normalizing with respect to the hadronic two-body channels π + π − and K + K − , a braching ratio B ee =Γ( p ̄ p → e + e − )/Γ( p ̄ p → total ) = (3.2 ± 0.9) × 10 −7 has been obtained
No description provided.
We present data on K − p reactions leading to the final states K 0 n , π 0 Λ, ηΛ, η'Λ, π − Σ + , K 0 Δ 0 (1230), and π − Σ + (1385) from a bubble chamber experiment at 14.3 GeV/ c K − lab momentum. Total and differential cross sections, Λ and Σ ∓ polarisations in π 0 Λ and π − Σ + final states as well as the Σ + (1385) density matrix elements are given.
NORMALIZED TO A TOTAL CROSS SECTION OF 21.5 +- 0.2 MB (GALBRAITH ET AL, PR 138B, 913 (1965)).
No description provided.
No description provided.
New experimental results are reported on diffractive dissociation of protons into (nπ + ) in proton-proton collisions at a centre-of-mass energy of s = 45 GeV . The data were obtained using the Split-Field-Magnet detector at the CERN Intersecting Storage Rings. We have searched for resonance contributions and found peaks at mass values of 1.5 GeV, 1.65 GeV, and 2.1 GeV. A dip in d σ d t is observed at low t and low mass; it is most pronounced for events with neutrons emitted at 90° in the Gottfried-Jackson frame. The correlation between mass and slope depends strongly on θ J . The cross section of the channel pp → pnπ + is 400 ± 110 μb at s = 45 GeV , giving an energy dependence of s −0.30±0.07 for isospin exchange zero in this channel.
SCALE UNCERTAINTY 20 PCT IS INCLUDED IN ERROR.
SIG(P P --> P N PI+) IS NEARLY EQUAL TO SIG(P P --> P (N PI+)) WHICH WAS ACTUALLY MEASURED, SINCE THE CROSS SECTION OF THE REACTION P P --> N (P PI+) IS LESS THAN .1 MUB AS MEASURED BY N. KWAK ET AL., PL 62B, 359, 1976.
EXTRAPOLATING TO T=0 AND ALLOWING FOR OTHER DECAY MODES YIELDS RESULT.
A comparison of K±p and p±p elastic scattering is made for incident energy 50 to 175 GeV. Average values of 0.19±0.04 and 0.11±0.02 GeV2 were found for the invariant-momentum-transfer values of the Kp and pp crossover points, respectively.
KP AND PP CROSSOVER POINTS AT -T = 0.19 +- 0.04 AND 0.11 +- 0.02 GEV**2 (AVERAGE VALUES) RESPECTIVELY.
We have measured charged-particle multiplicities and elastic and inelastic cross sections for π+p and pp interactions at 60 GeV/c. The data are from a 30 000-picture exposure of the 30-inch bubble chamber to a tagged but unseparated positive-particle beam at Fermilab. The low-order moments of the inelastic multiplicity distributions for all charged particles are 〈n〉 = 5.60±0.09, f2 = 0.96±0.31, and 〈n〉D = 2.19±0.06 for pp reactions and 〈n〉6.23±0.10, f2 = 1.63±0.37, and 〈n〉D = 2.22±0.06 for π+p collisions.
NORMALIZED TO A TOTAL CROSS SECTION OF 38.3 MB. CORRECTED FOR SMALL -T LOSSES AND FOR PI0 MESONS.
NORMALIZED TO A TOTAL CROSS SECTION OF 23.2 MB. CORRECTED FOR SMALL -T LOSSES AND FOR PI0 MESONS.
FORWARD CROSS SECTIONS ARE CONSISTENT WITH OPTICAL POINT FOR PURELY IMAGINARY ELASTIC AMPLITUDES.
No description provided.
Measurements of the proton-proton total cross section have been made with increased precision (±0.6%) over the ISR energy range s =23.5−62.7 GeV . Two different experimental methods gave consistent results, showing that the total cross section increases 10% over the ISR range and in addition that the absolute value of the ISR luminosity can be measured to ±0.9%.
CROSS SECTIONS ARE A WEIGHTED AVERAGE OF THOSE OBTAINED BY THE PISA-STONY BROOK METHOD AND BY THE CERN-ROME (OPTICAL THEOREM) METHOD.
We compare some aspects of the N→N π , N→N ππ and N → Λ K diffractive fragmentation systems induced by 14.3 GeV/ c incident K − mesons with those obtained in pp interactions at ISR energies. The similarity between the low-mass Nπ and Nππ systems produced by different incident particles at c.m. energies differing by an order of magnitude is very striking. The shapesof the mass spectra (not the M 2 / s spectra) are approximately independent of s , both in the resonant and non-resonant diffractive dissociation components. These findings, as well as features of the differential cross sections and decay angular distributions, indicate that the (asymptotic) diffractive dynamics operative at ISR energies is already dominant at 10–20 GeV/ c , remains essentially unchanged over this broad energy range, and has approximate vertex factorization properties.
No description provided.
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