Proton-antiproton and proton-proton elastic scattering have been measured in the four-momentum transfer range 0.001⩽| t |⩽0.06 GeV 2 for center-of-mass energy 52.8 GeV at the CERN Intersecting Storage Rings (ISR). Using the known pp total cross section, a simultaneous fit to the pp̄ and pp differential cross sections yields the pp̄ total cross section; in addition, we obtain the ratio of the real-to-imaginary part of the forward nuclear-scattering amplitude and the nuclear-slope parameter for both pp̄ and pp. Our results show conclusively that the pp̄ total cross section is rising at ISR energies and lend support to conventional theories in which the difference between the pp̄ and pp total cross section vanishes at very high energy.

Antiproton-proton and proton-proton small-angle elastic scattering was measured for centre-of-mass energies s =30.6, 52.8 and 62.3 GeV at the CERN Intersectung Storage Rings. In addition, proton-proton elastic scattering was measured at s =23.5 GeV . Using the optical theorem, total cross sections are obtained with an accuracy of about 0.5% for proton-proton scattering and about 1% for antiproton-proton scattering. The measurement of the interference of the Coulomb scattering and the hadronic scattering permits a determination of the ratio of the real-to-imaginary part of the forward hadronic scattering amplitude. Also presented are measurements of the hadronic slope parameter.

We measured the differential cross section for p̄p and pp elastic scattering in the momentum-transfer range 0.01 <| t | < 1.0 GeV 2 at the CERN Intersecting Storage Rings with center-of-mass energy s = 52.8 GeV . Fitting the differential cross section with an exponential [ A exp ( bt )], we found b p p = 13.92 ± 0.59 GeV −2 for | t | < 0.05 GeV 2 , whilst for | t | > 0.09 GeV 2 , b p p = 10.68 ± 0.26 GeV −2 . Using the optical theorem, we obtained for the total cross section σ tot ( p p)= 44.86 ± 0.78 mb and, by integrating the differential cross section, we obtained for the total elastic cross section σ el ( p p) = 7.89 ± 0.28 mb . Calculations of σ tot combining elastic-rate and total-rate measurements are also given. All of these measurements were also performed for pp scattering at the same energy, and the results for both reactions are compared.

Antiproton-proton and proton-proton small-angle elastic scattering have been measured for centre-of-mass energies √ s = 30.7 and 62.5 GeV at the CERN Intersecting Storage Rings (ISR). Antiproton-proton and proton-proton total cross sections are obtained using the optical theorem. The measurement of the Coulomb scattering and its interference with the nuclear scattering allows a determination of the ratio of the real-to-imaginary part of the forward nuclear scattering amplitude. Also presented are measurements for the nuclear slope parameter at √ s = 62.5 GeV. Our new results reinforce the conclusions drawn recently from our measurements at √ s = 52.8 GeV. In particular, the pp̄ total cross section is rising at ISR energies and should continue to rise well beyond these energies.

We report a measurement of the p p total cross section at √ s =1.8 TeV using a luminosity-independent method. Our result is σ T =72.1±3.3 mb ; we also derive the total elastic cross section σ el =16.6±1.6 mb. A value is obtained for the total single diffraction cross section of 11.7±2.3 mb.

We report a measurement of the p p ̄ total cross section at s =1.8 TeV at the Fermilab Tevatron Collider, using the luminosity independent method. Our result is σ T =71.71±2.02 mb. We also obtained values of the total elastic and total inelastic cross sections.

We have measured the antiproton-proton total cross section at √s =1.8 TeV at the Fermilab Tevatron Collider; the value obtained is 78.3±5.9 mb. B, the nuclear slope parameter for elastic scattering, was measured to be 16.3±0.5 (GeV/c)−2. From these data, we derive a value for the total elastic cross section.

The proton-antiproton total cross section was measured at the center-of-mass energy of s = 541 GeV at the S p pS at CERN using a luminosity dependent method. The result σ tot =63.0±2.1 mb is in agreement with the luminosity independent measurement performed earlier by the UA4 Collaboration.

The proton-antiproton total cross section was measured at the CM energy √s = 546 GeV . The result is σ tot = 61.9± 1.5 mb . The ratio of the elastic to the total cross section is σ e ℓ / σ tot = 0.215±0.005. A comparison to the lower energy data shows that the increase of the total cross section with energy is very close to a log 2 s behaviour.

Proton-antiproton elastic scattering at CM energy 540 GeV has been studied in the t -range 0.04 < − t < 0.45 GeV 2 . The data are well fitted by the form exp ( bt ) with b = 17.1 ± 1.0 GeV −2 for | t | = 0.04 − 0.18 GeV su 2 and b = 13.7 ± 0.2 ± 0.2 GeV −2 for | t | = 0.21−0.45 GeV 2 . A luminosity measurement combined with the optical theorem gives σ tot = 67.6 ± 5.9 ± 2.7 mb and σ e1 / σ tot = 0.209 ± 0.018 ± 0.008.

Topological and channel cross sections are given for annihilation and inelastic final states produced in p p interactions at 9.1 GeV/c. Cross sections for prominent resonances in specific channels and charged pion, ϱ 0 and Δ ++ inclusive cross sections are also presented.

A detailed account is given of high-precision measurements of the total hadronic cross sections of proton-antiproton and proton-proton interactions at centre-of-mass energies of 30.6, 52.8 and 62.7 GeV. The experiment was performed at the CERN Intersecting Storage Rings (ISR) using the total interaction-rate method, in which additive correction terms for trigger losses were held to less than 6% of the final result. An experimental determination of the vertical beam-displacement scale permitted luminosity-monitor calibrations to be made with high intrinsic accuracy. The overall precision (systematic and statistical errors combined) achieved in the total cross sections was ± 1.1% for proton-antiproton reactions and 0.7% for proton-proton reactions. In the proton-proton case the measurement was the most precise such measurement made at the ISR.

Reactions p p → p p and p p → n n were studied at the kinetic energy 230 MeV of incident p by using bubble chamber films. Total cross sections for both of the reactions were found to be 51.2 ± 1.6 mb and 9.1 ± 0.6 mb, respectively. Differential cross sections are well explained by the phenomenological theory given by Bryan and Phillips.

An extensive investigation of antiproton-proton interactions at 5.7 GeV/c without strange-particle production was carried out using a hydrogen bubble chamber. Cross-sections for different channels are given and discussed. The reliability of the analysis was checked using artificially generated events. The cross-sections for elastic scattering, for all processes involving annihilation, and for all other inelastic processes are respectively σel=(16.3±0.6)mb,σannlbil=(22.5±2.0)mb, σinel=(24.8±2.0)mb. TheN * 1:38 is present both in the single and multiple pion production channels. For the reaction MediaObjects/11539_2007_Article_BF02720569_f1.jpg a cross-section of (1.05±0.21) mb was obtained. Cross-sections forN * 1238 production in other channels are also given. Some indication of the presence ofI=1/2 isobars was found in the nucleon-pion and the nucleon-two-pion systems. The inelastic nonannihilation reactions were found to be strongly peripheral. The one-pion exchange model including either a form factor or corrections for absorption was applied to the reaction MediaObjects/11539_2007_Article_BF02720569_f2.jpg . Neither version of the model could correctly account for all features of the reaction. The average number of pions in the annihilation was found to be 7.3±0.6. The presence of an asymmetry in the angular distribution of the charged pions was confirmed at this energy; it is due mostly to high-energy pions. The production of ρ and ω mesons was observed in various annihilation channels. Rates of up to 80% for ρ production and up to 15% for ω production were obtained by fitting phase-space and Breit-Wigner curves to the effective-mass distributions of different channels.

The differential cross sections of p p elastic scattering at 0.7 GeV/ c were obtained in the range 0.0018<| t |⩽0.0320 GeV 2 . From the interference between the Coulomb and the nuclear amplitude, the ratio of real to imaginary part of the forward nuclear amplitude was found to be +0.33±0.04.

Differential cross sections for p p elastic scattering have been measured for very small momentum transfers at six different incident antiproton momenta in the range 3.7 to 6.2 GeV/c by the detection of recoil protons at scattering angles close to 90°. Forward scattering parameters σ T , b , and ϱ have been determined. For the ϱ-parameter, up to an order of magnitude higher level of precision has been achieved compared to that in earlier experiments. It is found that existing dispersion theory predictions are in disagreement with our results for the ϱ-parameter.

The small-angle elastic scattering for pp at s=23.5, 30.7, and 52.8 GeV and for p¯p at s=52.8 GeV are measured. The data are normalized on Coulomb scattering. Using the optical theorem and the best estimate of the real part of the forward scattering amplitude, ρ(pp¯)=0.1, we obtain σtot(p¯p)=44.1±2.9 mb for the total cross section and b(p¯p)=13.6±2.2 GeV−2 for the nuclear slope parameter. This supports the dispersion relation prediction that σtot(p¯p) will start to rise above Elab≈200 GeV.

Results are presented on the charge exchange reaction\(\bar pp \to \bar nn\) and\(\bar np\) annihilations from bubble chamber exposures to antiproton beam of momenta 700 and 760 MeV/c. The differential cross section of\(\bar pp \to \bar nn\) shows a forward spike followed by a clear dip bump structure. Total annihilation cross section of\(\bar np\) for average\(\bar n\) momentum of 700 MeV/c has been evaluated to be 55.4±2.2 mb. The multiplicity, Feynmanx andpT2 distributions for inclusive charged pions in\(\bar pp\) and\(\bar np\) annihilations are found to be similar. The emission of charged pions from\(\bar np\) annihilations are found to be consistent with thermodynamic models with temperature ∼110 MeV.

Absolute inclusive cross sections for\(\bar pp\) interactions at 7.3 GeV/c are given. The data cover prong cross sections,V0, γ production and inclusive charged particle (p/π) production. Separation has been made into annihilation and non-annihilation components. Inclusive π+, π− production in the processes of\(\bar pp\) annihilation and non-annihilation are compared with simple quark models.

We have measured ρ, the ratio of the real to the imaginary part of the p¯p forward elastic-scattering amplitude, at √s =1.8 TeV. Our result, ρ=0.140±0.069, is compared with extrapolations from lower-energy data based on dispersion relations, and with the UA4 value at √s =546 GeV.

The antiproton-proton small-angle elastic-scattering distribution was measured at\(\sqrt s \) GeV at the Fermilab Tevatron Collider. A fit to the nuclear-scattering distribution in the range 0.065≤|t|≤0.21 (GeV/c)2 givesb=(16.2±0.5±0.5) (GeV/c)−2 for the logarithmic slope parameter. Using the optical theorem and the luminosity from Collider parameters, we obtain σtoto(1+ρ2)1/2 =(61.7±3.7±4.4)mb.

We have measured $\rho$ , the ratio of the real to the imaginary part of the $p \bar{p}$ forward elastic scattering amplitude, at $\sqrt{s}$ = 1.8  TeV. Our result is $\rho$ = 0.132 $\pm$ 0.056; this can be combined with a previous measurement at the same energy to give $\rho$ = 0.135 $\pm$ 0.044.

The inclusive production of photons in\(\bar pp\) interactions has been studied at incident momentum of 12 GeV/c. Topological cross section has been presented and KNO distribution for\(\bar pp\) interactions has been studied. Inclusive cross section for γ production has been measured to be 149.5±8.8 mb. Bulk of these photons come from π0 decays whose cross section has been evaluated independently to be 60.4±7.9 mb. Signals of η and ω have been seen in γγ and π+π-π0 decay modes and their inclusive cross sections have been estimated to be 14.9±8.8 mb and 14.6±7.0 mb respectively. Results on average multiplicities of γ and two particle correlation parameters are presented. Neutral pions seem to be more strongly correlated than the charged pions. The inclusive distributions of the Feynmanx andpT/2 of the photons are compared with expectation from charged pions on the basis of charge independence. Energy dependence of the normalised invariant distributions has been studied. The distribution of the scaling variablez of photons ine+e− and\(\bar pp\) interactions has been compared.

The real-to-imaginary ratio of the p p forward elastic scattering amplitude has been measured at the LEAR facility of CERN by the Coulomb-nuclear interference method at seven beam momenta between 181 and 590 MeV/ c . The ratio is positive at 590 MeV/ c , becomes negative below 500 MeV/ c , reaches a minimum at 260 MeV/ c and then crosses zero again at about 230 MeV/ c .

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