J. Gress

Multiplicity of charged particles in 800 GeV p-p interactions

Abstract Results are reported concerning the charged-particle multiplicity distribution obtained in an exposure of the high-resolution hydrogen bubble chamber LEBC to a beam of 800 GeV protons at the Fermilab MPS. This is the first time that such data have been available at this energy. The distribution of the number n ch of charged particles produced in inelastic interactions obeys KNO-scaling. The average multiplicity is 〈 n ch 〉 = 10.26±0.15. For n ch ⩾8 the data can be well fitted to a negative binomial. The difference between the overall experimental multiplicity distribution and that resulting from the latter fit is in agreement with the contribution expected from diffractive processes.

Inclusive Charm Cross-Sections in 800-GeV/c p p Interactions

Abstract We report a measurement of the inclusive D/D production cross section in 800 GeV/ c proton-proton interactions. The experiment used the high resolution bubble chamber LEBC exposed to an 800 GeV/ c proton beam at the Fermilab MPS. We obtain σ( D/ D )=59 −15 +22 μ b (statistical errors), having analysed 25% of the total data sample. Comparison with 400 GeV/ c pp dat a obtained with LEBC at CERN shows a D/D cross section increase by a factor of 1.7 −0.5 +0.7 . This is in good agreement with fusion model calculations.

Measurement of the stopping power of nuclei for 100 GeV/c protons and antiprotons

Abstract We have studied the reactions p+A→ (p, n)+X and p +A→ p +X at beam momenta of 100 GeV/c for Mg, Ag and Au targets. The rapidity loss of the leading final state protons, antiprotons, and neutrons has been obtained as a measurement of the nuclear stopping power and correlated with the number of slow protons and the multiplicity and momentum of the associated charged particles.

Monte Carlo simulation of extensive air showers initiated by gamma rays and protons

A new approach to simulate gamma ray and proton extensive air showers (EAS) is presented with a detailed treatment of the electromagnetic component. In this method a hybrid Monte Carlo program is constructed which utilizes two existing codes: SHOWERSIM and EGS4. Results for EAS generated by vertical gamma rays and protons with primary energies of 1013, 1014, 1015 and 1016 eV are reported for different threshold energies at detection level. Shower size fluctuations, lateral distributions and corresponding fits are presented. Similarities and differences between gamma ray and proton initiated showers are discussed.

Secondary particle identification using the relativistic rise in ionization

Abstract We report on the data analysis and techniques used to determine particle identification from the relativistic rise in ionization as detected by CRISIS, a 1 × 1 × 3 m 3 , 192 cell, ionization-sampling drift chamber containing an 80% argon/20% carbon dioxide gas mixture. For 100 GeV/ c protons/antiprotons (pions) we obtain an ionization FWHM of 7.6% (7.9%), which compares well with the design value of 7.8%. The separation between the mean ionization values for the protons and pions was determined to be 7.9%. We also present the analysis of particle identification for secondary particles produced by interactions in the bubble chamber. A statistical method for correcting for the overlapping ionization curves from secondary protons/antiprotons and pions is discussed.

Vector boson production in hadron nuclear collisions

Abstract We report a search for the production of light quark vector bosons in hadron-nucleus collisions at 100 GeV bombarding energy. We find surprisingly few of these resonances produced. The lack of these particles is though to be due to the absorption by the many modestly energetic nucleons and the few anti-nucleons in the final state.

Inclusive charged pion production in hadron-nucleus interactions at 100 and 320 GeV/c

AbstractAn experiment has been performed with the Fermilab 30-inch bubble chamber and Downstream Particle Identifier to study inclusive charged pion production in the high energy interactions of π±,K+,p and

The angular distributions of charged secondaries in electromagnetic and hadronic extensive air showers at 10, 100, 1000 and 10000 TeV

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