J.P. Silverman

Inclusive production of neutral strange particles by 147 GeV/cπ+/K+/p interactions in hydrogen

Results are presented from a study of inclusive neutral strange particle production by a 147 GeV/c tagged π+/K+/p beam in the Fermilab 30-inch hydrogen bubble chamber. The experiment made use of the proportional hybrid spectrometer system. Results are based on 995 KS0, 485 Λ, and 83 Λ found in a sample of 132 000 pictures. Cross sections are given for inclusive production of these particles by each of the three beam particles, and comparisons are made with measurements at other energies. Topological cross sections are also calculated, and KNO multiplicity scaling is investigated. Distributions are presented of invariant cross sections as functions of the Feynman scaling variable x and c.m. rapidity y. The transverse momentum-squared distributions with their fitted slopes are also given. Comparisons are made of the production characteristics for the three beam types.

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.

Impact parameter analysis of multiparticle production in π−p interactions at 15 and 147 GeV/c☆

Abstract A recently proposed method of calculating experimental lower bounds, b L , on the root-mean-squared impact parameter of multiparticle processes has been applied to a variety of reactions in π − p interactions at 15 and 147 GeV/ c . The values obtained for b L show a decrease of the root-mean-squared impact parameter with increasing multiplicity at fixed energy and a very slow increase, if any, of b L with energy at fixed multiplicity. Furthermore, the results might indicate that absorption effects in multiparticle production in π − p interactions are not important. The transverse momentum transfer correlation matrices calculated in this paper have a diagonal form in agreement with multiperipheral type models.

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.

Comparison of 147 GeV/c π−p low transverse momentum hadron production with deep-inelastic leptoproduction

Distributions with respect toz andzR for the fastest and second fastest particles produced in both beam and target hemispheres from 147 GeV/c π− interactions are compared with each other and with the distributions for the fastest and second fastest particles from deepinelastic leptoproduction and Field-Feynman curves. The distributions and curves for the fastest particles are very similar, with the exception of the identified protons. Those for the second fastest are in agreement. Distributions with respect toz′R for the first through fourth fastest particles (excepting the protons) are all similar, suggesting that the shape of the distributions may be determined by the available longitudinal phase space.

Triple-Regge analysis of the reactions π−p→ pslow + X and π−p → πfast− + X at 147 GeV/c☆

Abstract In this paper we present new data for the reactions π−p→pslow+X− and π−p→πfast− + X+ at 147 GeV/c. This is the first time that experimental information on these two processes has been obtained using the same apparatus at Fermilab energies. The triple-Regge formalism is applied to the differential cross sections dσ/dMx2 of both reactions using all the data at present available in the literature. A good description of the data is obtained when parameters from a triple-Regge fit of the reaction pp → p + X are used, together with the assumption of factorization of the pomeron and the reggeons. The equality of the dσ/dMx2 distributions of the two reactions may be explained in terms of an interesting assumption in the framework of the independent quark model and imposes an additional relation between the triple-Regge terms.

Inclusive and semi-inclusive charge structure in π−p multiparticle production at 147 GeV/c

Abstract A new method of analysis (leading charge model) based on the zone graph technique is used to separate charged particles produced in the target, projectile and central regions of phase space. A significant fraction of the centrally produced particles follow a Bose momentum distribution with temperature of 131 ± 2 MeV.