Measurements of the total cross section have been performed at the ISR with c.m. energies between 23.5 GeV and 62.5 GeV. Two independent experimental methods have been applied, a measurement of total interaction rate and of small angle elastic scattering. Both experiments give consistent results showing that the total cross section increases by (11.8±1.5) % over the ISR energy range. This experiment has also measured the slope of the forward diffraction peak in elastic scattering at small momentum transfer. The elastic cross section shows the same relative rise as the total cross section, and the ratio λ of elastic to total cross section approaches a constant value of λ =0.178±0.003.
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TOTAL CROSS SECTION FROM (INTERACTION RATE)/(LUMINOSITY). SYSTEMATIC ERROR <0.8 PCT.
TOTAL CROSS SECTION FROM APPLYING THE OPTICAL THEOREM TO SMALL ANGLE ELASTIC SCATTERING EXTRAPOLATED TO T=0.
Measurements of the cross section for the production of electron pairs with invariant masses between 4 and 8.7 GeV are presented as a function of the centre-of-mass energy ( s = 28 to s = 62 GeV ) of the colliding proton beams. A significant excess of events is observed in the region 8.7 to 10.3 GeV; these are ascribed to the ϒ(9.5 GeV) resonances and estimates of the production cross sections are given.
Axis error includes +- 40/40 contribution (Due to the uncertainty in efficiency).
Axis error includes +- 40/40 contribution (Due to the uncertainty in efficiency).
We have measured the charge-exchange reaction pp → (p π + ) (p π − ) at s = 23, 31, 45, 53, and 63 GeV at the ISR, using the Split Field Magnet detector. The data are characterized by a sharp forward peak of width 0.02 (GeV/ c ) 2 , followed by a much gentler slope at higher | t |; sizeable Δ ++ , Δ 0 , and N 0 production is observed in the (Nπ) mass spectra. Two different components are present in the data following power-law energy dependence of the type p lab − n with n 1 = −1.63 ± 0.13 and n 2 = −0.96 ± 0.07, respectively, indicating the onset of mechanisms in competition with pion exchange at ISR energies.
CHARGE EXCHANGE DOUBLE DIFFRACTION DISSOCIATION OF PROTONS. DEL++, DEL0, N(1520)0 AND N(1688)0 RESONANCES IDENTIFIED IN PROTON-PION MASS SPECTRA.
We report results on a new measurement of the double diffractive reaction pp → (p π + π − ) (p π + π − ) at the ISR obtained with the Split Field Magnet detector. Experimental procedures and data analysis are discussed in detail. The cross section measured at the five standard ISR energies exhibits an increase of (55 ± 7)% in the s -range from 549 to 3892 GeV 2 .
DOUBLE DIFFRACTION DISSOCIATION OF PROTONS.
We report on a study of the charge-exchange reaction pp → nΔ ++ (1232) at the CERN intersecting storage rings (ISR) in the energy range √ s = 23 to 53 GeV. From our analysis of the energy dependence of the total cross-section, of the differential cross-section d σ /d t and of the decay angular distributions we find evidence that pion exchange is dominant up to √ s = 23 GeV and that ( ϱ +A 2 ) exchange dominates the reaction for √ s ⩾ 30 GeV, as described by simple Regge-pole models.
THE ERRORS ARE DUE TO STATISTICAL ERRORS AND BACKGROUND SUBTRACTION ERRORS COMBINED IN QUADRATURE.
THE ERRORS ARE DUE TO STATISTICAL ERRORS AND BACKGROUND SUBTRACTION ERRORS COMBINED IN QUADRATURE.
No description provided.
Measurements of the double differential cross sections for ππ and pπ production in pp collisions at the CERN ISR are presented for 5 c.m. energies s = 22, 30, 44, 53, 62 GeV . Charge and transverse momentum correlations are also reported.
No description provided.
No description provided.
No description provided.
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.
The inclusive production of low-momentum charged pions, kaons, and protons has been measured at x = 0 over the ISR energy range 23 < √ s < 63 GeV. The average increase in the invariant differential cross section is 36 ± 2% for π + , 41 ± 2% for π − , 52 ± 8% for K + , 69 ± 8% for K − , 8 ± 5% for p, and 84 ± for p ̄ . Pions have been measured in the range 0.04 < p T < 0.4 GeV/ c , kaons over 0.1 < p T < 0.3 GeV/ c , and nucleons over 0.1 < p T < 0.5 GeV/ c .
No description provided.
No description provided.
No description provided.
Results are reported for the invariant differential cross-section of charged pions produced at x = 0 in proton-proton collisions at the CERN ISR. The range covered is 40 to 400 MeV/c in transverse momentum and 23 to 63 GeV in collision energy. The inclusive cross-section for π + and π − are increasing by 36 ± 2% and 41 ± 2%, respectively over the ISR energy range with a somewhat stronger increase at the lowest transverse momenta. The transverse momentum distribution is well described by an exponential in the transverse energy.
No description provided.
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.
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