Secondary particle yields from 450 GeV/c protons on beryllium, a precise measurement for present and future neutrino beam calculations

Results on charged K and π production rates and their ratios measured by the SPY/NA56 experiment for 450 GeV/c proton interactions on beryllium targets are reported here. The present data sample covers the secondary particle momentum range between 7 GeV/c and 135 GeV/c in the forward direction. Experimental accuracies of 3% for K/π ratios and of 5–10% for particle yields have been achieved.     

Measurement of the production cross-section of positive pions in the collision of 8.9 GeV/c protons on beryllium

The double-differential production cross-section of positive pions, , measured in the HARP experiment is presented. The incident particles are 8.9 GeV/c protons directed onto a beryllium target with a thickness of 5% of a nuclear interaction length. The measured cross-section has a direct impact on the prediction of neutrino fluxes for the MiniBooNE and SciBooNE experiments at Fermilab. After cuts, 13 million protons on target produced about 96000 reconstructed secondary tracks which were used in this analysis. Cross-section results are presented in the kinematic range 0.75 GeV/c≤p_π≤ 6.5 GeV/c and 30 mrad≤θ_π≤ 210 mrad in the laboratory frame.     

Large-angle production of charged pions by 3-12.9?GeV/c protons on beryllium, aluminium and lead targets

Measurements of the double-differential π^± production cross-section in the range of momentum 100 MeV/c≤p< 800 MeV/c and angle 0.35 rad ≤θ<  2.15 rad in proton–beryllium, proton–aluminium and proton–lead collisions are presented. The data were taken with the HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 GeV/c to 12.9 GeV/c hitting a target with a thickness of 5% of a nuclear interaction length. The tracking and identification of the produced particles was performed using a small-radius cylindrical time projection chamber (TPC) placed inside a solenoidal magnet. Incident particles were identified by an elaborate system of beam detectors. Results are obtained for the double-differential cross-sections d²σ/dpdθ at six incident proton beam momenta (3 GeV/c, 5 GeV/c, 8 GeV/c, 8.9 GeV/c (Be only), 12 GeV/c and 12.9 GeV/c (Al only)) and compared to previously available data.     

Large-angle production of charged pions by 3?GeV/c–12?GeV/c protons on carbon, copper and tin targets

A measurement of the double-differential π^± production cross-section in proton–carbon, proton–copper and proton–tin collisions in the range of pion momentum 100 MeV/c≤p<800 MeV/c and angle 0.35 rad≤θ<2.15 rad is presented. The data were taken with the HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 GeV/c to 12 GeV/c hitting a target with a thickness of 5% of a nuclear interaction length. The tracking and identification of the produced particles was done using a small-radius cylindrical time projection chamber (TPC) placed in a solenoidal magnet. An elaborate system of detectors in the beam line ensured the identification of the incident particles. Results are shown for the double-differential cross-sections d²σ/dpdθ at four incident proton beam momenta (3 GeV/c, 5 GeV/c, 8 GeV/c and 12 GeV/c). PACS 13.75.Cs; 13.85.Ni     

Direct photon production from pions and protons at 200 GeV/c

Direct photon production has been studied by an experiment performed with the NA3 spectrometer at CERN, using incident negative and positive beams at 200 GeV/c interacting with an isoscalar Carbon target. Two different triggers have been used; one of them requires the photon conversion. The experiment is sensitive to direct photons produced with 3.0≦P _T ≦6 GeV/c and center-of-mass rapidity ?0.4≦y ^*≦1.2. Inclusive cross sections are given for incident π^± and protons, and compared with second order QCD predictions; finally an estimation of the gluon structure function of the nucleon is given.     

ψψ production and limits on beauty meson production from 400 GeV/c protons

From a study of multimuon events obtained in a high luminosity proton-platinum experiment at 400 GeV/c, we find 5 ± 4ψψ events, which correspond to a production cross section σ(ψψ = 27 ± 10 pb. The observed production is compared to the ψψ events previously found in the same apparatus from incoming π^?; a comparison with QCD predictions is performed, giving a good agreement with expectations from gluon-gluon fusion. Finally, using like-sign dimuon, trimuon and quadrimuon events, we give model-dependent upper limits on beauty meson production: 2 nb/nucleon for central models, 20 nb/nucleon for diffractive production.     

Coherent production of particles by 67 GeV/c protons on emulsion nuclei

Coherent reactions were observed among one-, three- and may be five-prong interactions of 37 GeV/c protons in nuclear emulsion. Their cross sections were estimated and compared with other data on coherent production in emulsion.     

Single particle inclusive spectra of charged particles from antiproton-proton interactions at 5.7 GeV/c

A systematic study of single particle inclusive spectra of charged particles from ¯pp interactions at 5.7 GeV/c is presented and discussed in the framework of the Mueller-Regge approach to inclusive reactions. A comparison of our results with data at other energies points to specific properties of antiproton-proton interactions.I have greatly benefited from discussions with Dr. J. Cvach and Dr. V. imák. To Dr. V. imák I am also indebted for the encouragement during the preparation of this paper.     

Strange particle production from π−p interactions at 1.69 GeV/c

The three-body final states $\text{Σ}{}^{\mathrm{\pm }}\text{π}{}^{\mathrm{?}}\text{K}{}^0\text{, Σ}{}^{\mathrm{<mtext>0</mtext>}}\text{π}{}^{\mathrm{<mtext>0</mtext>}}\text{K}{}^{\mathrm{+}}$ and $\text{Λπ}{}^{\mathrm{<mtext>0</mtext>}}\text{K}{}^{\mathrm{+0}}$ produced from πp interactions at 1.69 GeV/c are examined. The quasi-two-body state Λ(1405)K⁰ is discussed in detail. In particular, the spin of Λ(1405) is determined, via the method of Byers and Fenster, to be consistent with $\text{1}\text{2}$. The Σ^±π^? mass spectrum is compared to that produced by various zero-range and effective-range parametrizations and the Λ(1405) is found to have a mass of 1405 MeV and width of 45–55 MeV. Production and decay characteristics of the quasi-two-body states $\text{Σ(1385)}{}^{\mathrm{<mtext>0</mtext>}}\text{K}{}^{\mathrm{<mtext>0</mtext>}}$ are reported.     

Inclusive highP T π0 production from π± and protons at 200 GeV/c

We have measured the inclusive cross-section for π⁰ production at large transverse momentum by 200 GeV/c positive and negative hadron beams on Carbon targets (2.9<P _T <6 GeV/c; ?0.4<y ^*<1.2). We used the NA3 spectrometer at the CERNSPS.     

Topological cross sections and charged particle multiplicities inpp interactions at 360 GeV/c

Using data obtained with EHS equipped with the Rapid Cycling Bubble Chamber (RCBC) exposed to a proton beam of 360 GeV/c, we calculate topological cross sections. We present in great detail the procedure and the techniques used to correct raw data. Finally, we give multiplicity moments and multiplicity correlations and we compare the values obtained in our experiment, together with data at other energies, with different models.     

Channeling of 1.1 GeV/c protons and pions

Channeling effects have been observed for 1.1 GeV/c protons and pions transmitted through a 1 mm thick germanium single crystal.     

Measurement of particle and antiparticle elastic scattering on protons between 6 and 14 GeV

Differential cross sections in the t-range between 0.02 and 1.5 GeV² have been measured for the elastic scattering of particles and antiparticles on protons at 6.4, 10.4 and 14 GeV for K^±p and 10.4 GeV for π^±p and p^±p. Large statistics have been achieved and systematic uncertainties have been minimized. The relative systematic uncertainty between particle and antiparticle data is less than 0.5%. Accurate measurements of the position of the first crossover between particle and antiparticle differential cross sections have been performed. As the energy increases from 6.4 to 14 GeV the K^±p crossover moves to smaller values by 0.010 GeV² with a statistical error of 0.006 GeV² and a systematic uncertainty of 0.005 GeV². The crossover positions at 10.4 GeV for π^±, K^± and p^± scale approximately with the interaction radii.     

Jet production from nuclei at 400 GeV/c

Results are presented from a calorimeter study on the production of jets in large-E_T proton-nucleus collisions at 400 GeV/c. Jet-like large-p_T events from eight nuclear targets are seen with a special jet trigger. As previously observed, the cross section for such events increases slightly faster than the atomic number, much like in the production of large-p_T single hadrons. Data on energy flows and multiplicities suggest that a heavy nucleus does not significantly widen the angular distribution of the beam remmants. In the central region the particle flow in hard nuclear collisions is similar to that in soft nuclear collisions.     

Neutral strange particle production in neutrino and antineutrino charged current interactions on protons

The production of the neutral strange particlesK ⁰, and invp and charged current interactions is studied in an experiment with the Big European Bubble Chamber. Mean multiplicities are measured as a function of the event variablesE _v,W ² andQ ² and of the hadron variablesx _F,z andp _T ² .K ^*± (892) and ^*± (1385) signals are observed, whereas there is no evidence for ^*- (1385) production invp scattering. Forward, backward and total mean multiplicities are found to compare well with the predictions of an empirical model for deep-inelastic reactions in the case of the strange mesonsK ⁰ andK ^*± (892) but less so for the strange baryons , and ^*± (1385). The strange baryon multiplicities are used to obtain the decuplet to octet baryon production ratio and to assess the probabilities of auu orud system to break up.