New experimental results are presented on proton-proton elastic scattering at centre-of-mass energies s =23 GeV and s =62 GeV . The data are obtained using the Split Field Magnet detector at the CERN Intersecting Storage Rings. The absolute differential cross-sections show an energy-dependent behaviour. The position of the diffraction minimum changes from t =(−1.44±0.02)GeV 2 at 23 GeV to (−1.26±0.03)GeV 2 at 62 GeV. The cross-section at the second maximum is increasing with s . The connection of these observations with the hypothesis of “geometrical scaling” is discussed.
63 K EVENTS.
380 K EVENTS.
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 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.
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.
The measurement of the proton-proton total cross section performed by the CERN-Pisa-Rome-Stony Brook Collaboration at the CERN ISR is discussed in detail. The total interaction rate, the elastic scattering rate in the forward direction, and the machine luminosity were measured simultaneously to obtain three different determinations of the total cross section. Consistent results were found, which made it possible to prove the reliability of the Van der Meer luminosity calibration within +-0.9% and to achieve a precision of +-0.6% in the measurement of the total cross section.
No description provided.
We present the results of a systematic analysis of charge-exchange double dissociation in proton-proton collisions at the CERN Intersecting Storage Rings. The data, obtained with the Split-Field Magnet detector, cover the entire ISR energy range between s = 23 GeV and s = 63 GeV at five standard energies.
CHARGE EXCHANGE DOUBLE DIFFRACTION DISSOCIATION OF PROTONS. THESE CROSS SECTIONS WERE REPORTED IN G. GOGGI ET AL., PL 72B, 265 (1977).
No description provided.
THE SEMI INCLUSIVE DENSITY MATRICES ARE ALSO GIVEN (P P --> DEL++ P PI- + DEL0 P PI+).
Prompt dimuon production has been measured. Events with mass up to 25 GeV/c2 are observed, as well as the J and ϒ resonances. Cross sections are given for J and ϒ production. For the continuum, the scaling function F(τ) is measured at very small values of τ=ms covering the range 0.05<τ<0.20.
No description provided.
HERE UPSILON = ALL USILON FAMILY. ANGULAR DISTBN. IS SEEN TO BE ISOTROPIC.
No description provided.
By using three different c.m. energies in pp interactions,\(\sqrt s \), 44, 62 GeV, it is shown that the average charged-particle multiplicity <nch> sclaes with\(\sqrt s \) once the correct hadronic energy available for multiparticle production,Ehad, is used as basic parameter. The pp data, analysed in this way, are compared with e+e− data at equivalent energies. The agreement is very satisfactory.
WITH SQRT(S) OF 30 GEV.
WITH SQRT(S) OF 44 GEV.
WITH SQRT(S) OF 62 GEV.
Measurements of pp→μ+μ−+X at s=44 and 62 GeV are compared. The data are taken under identical conditions utilizing clean proton-proton collisions from the CERN intersecting storage rings and confirm scaling to 5%. The observed μ+μ− yield is a factor of 1.6±0.2 larger than estimated from a simple parton model but is consistent with QCD. The pT dependence of the muon pairs agrees well with expectations from QCD.
No description provided.
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