Search

Kinematic properties of inclusive {ital p}+{ital A}{r arrow}{pi}{sup {minus}} and {ital A}{sub 1}+{ital A}{sub 2}{r arrow}{pi}{sup {minus}} at 200 GeV/nucleon are compared with {ital p}+{ital p}{r arrow}{pi}{sup {minus}} at 200 GeV/{ital c} using data of CERN SPS experiments. The partition temperature is found to be practically the same for all the reactions analyzed, suggesting an approximate scaling. The peak shift of pseudorapidity {eta} distributions of these nuclear reactions with respect to the peak of {ital pp}{r arrow}{pi}{sup {minus}} follows a geometrical law: {eta}{sup *}{congruent}({ital A}{sub 1}{sup 1/3}{minus}{ital A}{sub 2}{sup 1/3})/8, independent of energy. The mean free path {ital l} characteristic of the energy loss suffered by the projectile fireball passing through the nuclear target is {ital l}{congruent}6.21 fm. Semiempirical formulas for {l angle}{ital n}{sub {minus}}{r angle} of {ital p}+{ital A} and {ital A}{sub 1}+{ital A}{sub 2} reactions are proposed and tested using available data.

The pseudorapidity {eta} distributions of {pi}{sup {minus}} from {ital pp}, {pi}{sup +}{ital p}, and {ital K}{sup +}{ital p} collisions of a CERN SPS experiment at {ital P}{sub lab}=250 GeV/{ital c} are analyzed in terms of a covariant partition-temperature {ital T}{sub {ital p}} model, the asymmetry of the distribution being accounted for by a shift parameter {eta}{sup *}. Remarks are made on the properties of {ital T}{sub {ital p}} and {eta}{sup *}.

Analyses of P/sub perpendicular/ and x,z distributions of inclusive e/sup +/e/sup -/..-->..hh-bar from experiments at the SLAC storage ring PEP at 29 GeV confirm that there is only one temperature T = 196 +- 7 MeV of e/sup +/e/sup -/ annihilation for various hadrons, as predicted by Chou and Yang. It is found that TproportionalE/sup 1/4/ according to the TASSO data; its relationship with the impact parameter b sets a lower limit (for b = 0) T/sub 0/approx.106 MeV related to the effective light-quark mass m/sub q/ = 3,T/sub 0/approx. =318 MeV. Hadron multiplicities from PEP experiments, covering approx.3 orders of magnitude, are accounted for by a semiempirical formula derived from the Boltzmann factor with quark contents and a unique temperature T = 196 MeV for all hadrons under investigation.

A kinematic method is considered to estimate the quark mass from e/sup +/e/sup -/..-->..qq-bar..-->..hadrons. It is based on a well-known linear relationship between the average meson multiplicity and the fireball mass, crucial tests being made with ..pi.. production by pp collisions and p-barp annihilations. Applied to the multiplicity data of e/sup +/e/sup -/ annihilation from ADONE, the method yields for the effective mass of the light quarks 0.33 +- 0.03 GeV.

Cross sections of the inclusive reactions ..pi../sup -/A, p-barA, and ..gamma..A..-->..J/psi+... at P/sub lab/approx. =40 and 125 GeV/c are investigated using the geometric model with the same A dependence as expected from the Fermi distribution of nuclear density. The fits agree well with the data. An overall fit to all four sets of data assuming a constant absorption mean free path and a power law for the energy dependence of the radius parameter indicates no anomaly of J/psi production from the W and Pb targets. It is found that due to the threshold effect the temperature of J/psi is much cooler than the ..pi.. temperature. A remark is made on a similar formula for the cross section of the nucleus-nucleus reaction.

Fireball properties have been investigated using results of previous analyses of inclusive $p\ensuremath{-}p$ data in terms of a Bose-type distribution modified by a scaling parameter. A discussion is presented on the relation between the scaling parameter and the longitudinal velocity of the fireball. It is found that the transverse motion may account for large-${P}_{T}$ distributions at 90\ifmmode^\circ\else\textdegree\fi{} c.m. angle and that this motion is not detectable for ${P}_{T}l1.5$ GeV/c. The fireball mass is found to increase as ${({\ensuremath{\gamma}}_{\mathrm{c}.\mathrm{m}.}\ensuremath{-}1)}^{\frac{1}{2}}$, ${\ensuremath{\gamma}}_{\mathrm{c}.\mathrm{m}.}$ being the Lorentz transformation factor from lab to c.m. system.

Simple relationships are found for meson multiplicities as linear functions of the fireball mass, the energy dependence being determined by the scaling property of each reaction. In this way, only three parameters related to the proton, the meson, and the photon-lepton fireball, are needed to account for multiplicities from eight reactions: pp, ..pi../sup +/p, K/sup +/p, ..gamma..p, e/sup -/p, ..mu../sup -/p, and ..nu..p, as well as p-barp annihilation.

A remark is made on the Maxwell distribution, including the mass motion to account for the anisotropy of angular distribution. This distribution is used to analyze secondaries emitted at 180degree by p-nucleus reactions in a Pennsylvania--Los Alamos--Temple experiment. The velocity of the mass motion is compared with that of the Fermi motion.

Large-P/sub perpendicular/ distributions for ..pi../sup plus-or-minus/ and K/sup plus-or-minus/ from p-nucleus collisions of the Chicago-Princeton experiment are analyzed using a Bose-type distribution. A discussion is presented on the behavior of two parameters, temperature and transverse velocity of the fireball. The A dependence of cross sections is found to follow a power law A/sup alpha/, with ..cap alpha.. = 0.86 for ..pi../sup plus-or-minus/ as well as for K/sup plus-or-minus/. A comparison with data from a CERN ISR experiment shows a striking similarity in meson production by p-p and p-nucleus collisions. Remarks from the viewpoint of the Boltzmann factor are made about the P/sub perpendicular/ distribution of the new particle J (3.1) from nucleon-nucleus collisions. (AIP)

A discussion is given on crucial tests for the Hagedorn and the Boltzmann distributions for PT. Applications to the high energy π−p and pp experiments of Wisconsin and Berkeley justify the use of the Hagedorn distribution and rules out the Boltzmann distribution. Neither one is adequate for the secondaries of the pp annihilation experiments of Argonne and CERN. A thermodynamical model based on the Bose distribution satisfying the “scaling” law will be discussed.

The design is based on earlier experience with smaller magnetic-field systems. Details are included concerning the magnet, spark chambers, pulsers, counters, data box, and the geometry of the system, (J.R.D.)

The angular distributions near 0o and 180o of associated production π− + p → Ko + Λo/Σo have been measured at 4 GeV/c. The slope of the backward peak is about 1 4 that of the forward peak, and the polarization of the forward Λo's is small.

A spark chamber is described which has a magnetic field, and is operated with an event-triggered arrangement rather than a strict one such as found in earlier chambers. The performance of the system is discussed including capacity, particle identification, and scanning experience. Data are included on event identification and momentum precision. (J.R.D.)

An analysis of single particle distributions of π mesons from a high statistics pp anihilation at 2.32 GeV/c is presented. It has been found that in the reactions pp → n π with n = 4, 5, 6 and 7, the gross features of the c.m. longitudinal and the transverse momentum distributions follow close to the phase space. The c.m. longitudinal momentum distributions show an asymmetry, which is characteristic of the disfavoured fragmentation postulated by Chou and Yang. The magnitude of the asymmetry is found to decrease with the multiplicity n. A comparison between the experimental distributions and those computed from the multiperipheral model of Chan, Łoskiewicz and Allison is presented. An inclusive single particle distribution for π+ and a fit with the form (1 − x)c for the Feynman variable x > 0.68 is presented.

Recent CERN Intersecting Storage Rings data on inclusive p-p collisons have been analyzed using a Bose-type distribution with two parameters: temperature T and scaling factor lambda . The results of the analysis agree with the previous conclusion that the Feynman-Yang ent P/sub lab/ > 20 GeV/c and the lambda behaves as lambda yields 2/ gamma , gamma being the c.m. Lorentz factor. The temperature is found to be T approx equal 0.120 GeV (auth)

Properties of a Poisson-type distribution satisfying the same recurrence relation as the negative binomial distribution are investigated using the charged multiplicity data of\(\bar p\)p,pp, π+p,K+p ande+e − interactions. Its two parameters are found to deviate significantly from the predictions of the Giovannini-Van Hove model. Remarks are made on the property of quark content of the multiplicity due to fragmentation of colliding particles such asp,π/K ande under investigation.

Author(s): Goldhaber, Gerson; Fowler, William B.; Goldhaber, Sulamith; Hoang, T.F.; Kalogeropoulos, Theodore E.; Powell, Wilson M.

A set of programs for computing covariant phase space factors using the IBM-605 is described. Originally the programs were written to investigate K production in antiproton annihilation in terms of the statistical model. Theywere written with enough flexibility to permit their use on similar problems involving four to six secondary particles of another nature provided the particles can be ordered so that the last two particles in the successive integrals are identical. (W.D.M.)

K-meson production by p - bar annihilation was investigated using an isobar model. A comparison of the predictions of this model with the experimental data excludes the assumption of an isobar state of ( pi pi ) having a mass greater than three pion masses. (auth)