D. Bogert

Cross sections and charged multiplicity distributions for π−p and K−p interactions at 147 GeV/c

Abstract The results presented in this paper were obtained from a 105 000 frame exposure of the FNAL Hybrid Proportional Wire Chamber-30 inch Bubble Chamber System, in a tagged beam of 147 GeV/ c negative particles. Elastic, total and topological cross sections were obtained for both π − p and K − p interactions. Comparisons with other data, taken with various beam particles over large momentum intervals, show good agreement with KNO scaling, and similarity in the scaling behavior of σ n for the different beam particles.

Inclusive ϱ° production in π−p interactions at 205 GeV/c

Abstract The inclusive ϱ ° production cross section has been measured in the reaction π − p → π + π − X at 205 GeV/ c . We find σ ( ϱ ° ) = 13.5 ± 3.4 mb, with most of the production occuring in the central region. Assuming σ ( ϱ + ) ≈ σ ( ϱ − ) ≈ σ ( ϱ ° ), it is concluded that approximately one-third of the pions at this energy come from ϱ -decay.

Topological and leading particle cross sections for 147 GeV/c π− -p interactions☆

Abstract Results are reported based on a study of π − p interactions at 147 GeV/ c in the FERMILAB 30-inch Proportional Wire Hybrid Bubble Chamber System. We have measured the topological cross sections and separated two-prong elastic and inelastic channels. In addition, we have extracted leading particle cross sections using the increased momentum resolution of the downstream proportional wire chambers. We have compared our results with experiments and predictions of a simple fragmentation hyphothesis.

Inclusive and semi-inclusive ϱ0 production in π−p interactions at 147 GeV/c

Abstract We present data on inclusive and semi-inclusive ϱ 0 production in 147 GeV/ c π − p interactions. We find a total cross section of 7.3 ± 1.3 mb. Most of this cross section is found in the lower topology events (⩽ 10 prongs), and in the central and forward rapidity regions. The P T 2 dependence of ϱ 0 production, 〈: n > ϱ 0 per event, and the ϱ 0 / π + ratios are also discussed.

Charge asymmetry in inelastic π−p interactions at 205 GeV/c for particles with transverse momentum > 1.0 GeVc

Abstract In 205 GeV / c π − p inelastic interactions, negative particles with transverse momentum greater than 1.0 GeV / c moving forward in the center of mass outnumber similar positive particles by a factor of 3.7 to 1, greatly in excess of the corresponding ratio for small transverse momentum. The asymmetry is reversed in the backward direction. The forward asymmetry is most prominent in 2-, 4-, and 6-prong interactions, but both forward and backward asymmetries are also substantial for higher multiplicity interactions.

The production of μe events in antineutrino-nucleon interactions

Abstract A clear observation of μ + e − events produced in an antineutrino heavy neon-hydrogen experiment using the Fermilab 15 ft bubble chamber is reported. The relative production rate, Vee yield, and scaling variable distributions are presented, and the events are interpreted as charmed particle production from ocean quarks.

Pion and nucleon dissociation in π−p→π−π+π−p at 205 GeV/c

Abstract In a 48 000-picture exposure of the Fermilab 30-inch hydrogen bubble chamber to a 205 GeV/ c π − beam, we have measured 169 events of the reaction, π − p → π − π + π − p, with a cross section of 635 ± 61 μ b. This reaction proceeds almost entirely via low mass π − → 3 π and p → p ππ dissociation. Factorization is satisfied for p → pππ dissociation in πp and pp interactions.

Search for a charm changing neutral current in antineutrino interactions

Abstract A search for charmed particle production in anti neutrino-nucleon neutral current interactions is reported. The recognition signature used was positron decay of the charmed particle; however all single positron events found can be attributed to known sources. Based upon a possible singal of one event, the 90% confidence level upper limit for the rate of neutral current charmed particle production with subsequent positron decay relative to charged current interactions above the charm threshold is 1.45×10 −3 . Assuming a branching ratio of 0.1, we find the corresponding limit for the right handed u c coupling is 1.9×10 −2 .

Evidence for charged cluster emission in 147 GeV/ π−p collisions☆

Abstract A study of charged particle production in 147 GeV/c π − p collisions yields no evidence for an electrically neutral central region or corresponding rapidity plateau. The results do indicate that electric charge and transverse momentum may be locally conserved over small intervals on the rapidity axis. These results support a picture in which the observed hadrons are emitted in clusters whose quantum numbers vary as a function of rapidity and reflect the incident channel quantum numbers at the extremes of the rapidity scale.

The exclusive channel π-π-π+p in π-p interactions at 147 GeV/c

SummaryThe results of a study of the reaction π-p→π-π-π+p at 2 147 GeV/c carried out at the Fermilab Proportional Wire 30″ Bubble Chamber Hybrid Spectrometer are reported. More than 92% of the cross-section ((670±41) μb) for this reaction is contained in those for proton and pion diffraction dissociation. The cross-sections for pion diffraction events with three-pion invariant mass in given regions are in agreement with values obtained by extrapolation of fits to data at lower incidentpion momenta. ρ0π- events make an important contribution in the A1 and A2 mass regions, and the data are consistent with contributions from f0π- in the A3 mass region. The cross-section for proton diffraction events is in agreement with a smooth extrapolation of the data at lower momentum.RiassuntoSi presentano i risultati di uno studio della reazione π-p→π-π-π+p a 147 GeV/c realizzati 2 nello spettrometro ibrido della camera a bolle di 30″ proporzionale a filo del Fermilab. Più del 92% della sezione d’urto (670±4) μb) per questa reazione è contenuto in quelle della dissociazione di diffrazione per il protone e il pione. Le sezioni d’urto per gli eventi di diffrazione del pione con la massa invariante di tre pioni in regioni date sono in accordo con i valori ottenuti mediante l’estrapolazione di appros-simazioni per dati a minore impulso del pione incidente. Gli eventi di ρ0π danno un contributo importante nelle regioni di massa di A1 e A2 e i dati sono compatibili con i contributi da f0π- nella regione di massa di A3. La sezione d’urto per gli eventi di diffrazione del protone è in accordo con un’estrapolazione uniforme dei dati ad impulso minore.РезюмеСообщаются результаты исследования реакции π-p→π-π-π+p при 147 ГэВ/с, проведенного в Лаборатории Ферми. Более чем 92% поперечного сечения ((670±41) мбарн) для этой реакции связано с дифракционной диссоциацией. Поперечные сечения для событий дифракции пионов с инвариантной массой трех пионов в заданных областях согласуются со значениями, полученными в результате экстраполяции подгонки данных при меньших импульсах падающих пионов. События π0π- дают важный вклад в области масс A1 и A2. Полученные данные соответствуют вкладам f0π- в области массы A3. Поперечное сечение для событий дифракции протонов согласуется с плавной экстраполяцией данных данных при малых импульсах.