Inclusive Particle Production Research Articles

Inclusive strange particle production in π −p interactions at 6 GeV/c

The inclusive production of Λ, K S 0, Σ ±(1385) and K ∗±(892) in π −p interactions at 6 GeV/ c has been studied. The observed cross sections are: σ( Λ)=0.94±0.06 mb, σ(K S 0)=0.98±0.06 mb, σ( Σ +(1385))=60±7 μb, σ( Σ −(1385))=90±9 μb, σ( K ∗+(892))=216±28 μ b and σ( K ∗−(892))=41±8 μ b , respectively. The inclusive spectra of these particles are presented as functions of squared transverse momentum and Feynman scaling variable x. The polarization of Λ has also been investigated. It is found from a comparison with higher-energy data that the inclusive cross sections for Σ ±(1385) and the production ratios Σ ±(1385)/ Λ in π −p at 6 GeV/ c have not reached the high-energy limiting values.

Charged-particle production from neutron-nucleus collisions at 200 GeV/c

We have studied the inclusive production of charged particles in neutron-nucleus collisons using the M3 neutral beam at Fermilab. Differential particle yields, $\frac{\mathrm{dN}}{d\ensuremath{\eta}}$, in laboratory pseudorapidity, $\ensuremath{\eta}=\ensuremath{-}\mathrm{ln}[tan(\frac{{\ensuremath{\theta}}_{L}}{2})]$. from Be, Cu, and Pb targets are presented for the forward region $1.7\ensuremath{\le}\ensuremath{\eta}\ensuremath{\lesssim}6.5$ as well as the extreme backward region $\ensuremath{-}2.8\ensuremath{\le}\ensuremath{\eta}\ensuremath{\le}\ensuremath{-}1.6$. Comparisons are made with previously reported measurements of the forward yields. The backward yields are used to test the coherent tube model.

Particle and antiparticle production by 200 GeV/c protons in the charged hyperon beam at the CERN SPS

A charge hyperon beam has been brought into operation at the CERN SPS. Particles are identified by a DISC Čerenkov counter, and decay products are analysed by a magnetic spectrometer. Cross sections for the inclusive production of π + , K + , p , Σ + , Σ − , ζ − , d, and π − , K − , p , Σ + , Σ − , ζ − , ω − , d in the forward direction have been measured at laboratory momenta between 70 and 130 GeV/ c . This range of momenta corresponds to 0.35 ⩽ x ⩽ 0.66 for an incident proton momentum of 200 GeV/ c . Antihyperon ( Σ − , ζ − , Σ + ) and Σ + and ω − fluxes have been measured for the first time in a hyperon beam. Scaling behaviour is observed when the data are compared with the results from other experiments. The inclusive particle production cross sections have a (1 − x ) n dependence, where n is characteristics of the particle. A search has been made for new particles in the mass range 2–10 GeV/ c 2 . No evidence is found for such particles.

Particle and antiparticle production by 200 GeV/ c protons in the charged hyperon beam at the CERN SPS

A charge hyperon beam has been brought into operation at the CERN SPS. Particles are identified by a DISC Čerenkov counter, and decay products are analysed by a magnetic spectrometer. Cross sections for the inclusive production of π +, K +, p, Σ +, Σ − , ζ − , d, and π −, K −, p , Σ + , Σ −, ζ −, ω −, d in the forward direction have been measured at laboratory momenta between 70 and 130 GeV/ c. This range of momenta corresponds to 0.35 ⩽ x ⩽ 0.66 for an incident proton momentum of 200 GeV/ c. Antihyperon ( Σ − , ζ − , Σ + ) and Σ + and ω − fluxes have been measured for the first time in a hyperon beam. Scaling behaviour is observed when the data are compared with the results from other experiments. The inclusive particle production cross sections have a (1 − x) n dependence, where n is characteristics of the particle. A search has been made for new particles in the mass range 2–10 GeV/ c 2. No evidence is found for such particles.

Inclusive charged-Particle Production in Neutron-Nucleus Collisions

We have measured inclusive particle production in neutron-nucleus collisions at high energies. Data on positive and negative particles produced in nuclei, ranging in size from Be to Pb, are presented for essentially the full forward hemisphere in the center-of-mass system. Fits of the form ${A}^{\ensuremath{\alpha}}$ to the invariant production cross section indicate that $\ensuremath{\alpha}$ changes from \ensuremath{\sim}0.85 to \ensuremath{\sim}0.55 for laboratory rapidities ranging from 3 to 8. Multiperipheral models which invoke cut contributions to particle production in nuclei predict such behavior.

General features of [formula omitted] interactions at 32 GeV/ c

The general features of p p interactions at 32 GeV/ c are analysed in a bubble chamber experiment with a statistics of 5.2 μb/event. The inclusive production of neutral strange particles and pions is analysed and compared to results obtained at other energies and in pp interactions. Total cross sections are determined for various 4C reactions and the relative contributions of diffractive dissociation and ΔΔ production to the reaction p p→ p pπ +π − are estimated.

Inclusive neutral particle production in π −d interactions at 205 GeV

The inclusive production of neutral particles are studied in π −d interactions at 205 GeV. Topological distributions for the inclusive reactions π −d → γ + d, π −d → K s 0+x, π −d → Γ + x and the cross section for π − d → Γ + x are presented and compared with π −p and pp interactions at 100 and 205 GeV. The effects of double scattering are studied and π −n inclusive distributions are obtained and compared to results from π −p interactions (in hydrogen) at 205 GeV.

Inclusive production of neutral strange particles at 300 GeV: Triple-Regge behavior

The process p + nucleon → V 0+ anything has been studied at 300 GeV for V 0 = Λ 0, Λ 0 , and K S 0. The data are consistent with a simple Mueller-Regge formulation in the appropriate limit. Values of α( t) computed from the data agree with those expected from the simplest triple-Regge diagrams. If the pomeron is not a pure SU(3) singlet, a similar diagram is consistent with the Feynman x-dependence of the observed polarization of inclusively produced Λ 0.

Nuclear size dependence of inclusive particle production

The inclusive production of π +, π −, K +, K −, p and p for protons incident on carbon and tungsten targets was studied at the Internal Target Area of the Fermilab. We assume an A α dependence for the inclusive cross sections and report here on the variation of α with incident momentum, transverse momentum and particle species.

π+p,K+p, andpptopological cross sections and inclusive interactions at 100 GeV using a hybrid bubble-chamber-spark-chamber system and a tagged beam

${\ensuremath{\pi}}^{+}p$, ${K}^{+}p$, and $\mathrm{pp}$ interactions at 100 GeV are studied using the Fermilab hybrid 30-inch bubble chamber with associated downstream multiparticle spectrometer and an unseparated tagged positive beam. Topological cross sections and charged-particle-multiplicity moments are presented and good agreement is found with Koba-Nielsen-Olesen scaling. The charged-multiplicity second moment, ${f}_{2}^{\mathrm{cc}}$, and the second moment of produced (+ -) pairs, ${f}_{2}^{\ensuremath{-}\ensuremath{-}}$, are presented both with and without the diffractive-dissociation events, and are discussed in terms of the two-component model invoked to explain $\mathrm{pp}$ multiplicity distributions above 100 GeV. Single-particle inclusive distributions are presented and studied in terms of the Regge-Mueller forms of approach to scaling at asymptotic energies. Pomeron factorization is found to hold in the target-proton-associated backward center-of-mass hemisphere for inclusive particle production by incident ${\ensuremath{\pi}}^{+}$, ${K}^{+}$, and protons.

A study of the Landau hydrodynamical model predictions for high-energy inclusive charged particle production

The predictions of the Landau hydrodynamical model are compared with the experimental results on the one-particle distributions from proton-proton collisions at the CERN ISR. Both one-dimensional and three-dimensional versions of the model are considered. The parameters of the model are the velocity of sound in nuclear matter, c 0, which describes the expansion and cooling of the fluid, and the break-up temperature, T c, at which the particles emerge. The best agreement between the theoretical and experimental distributions is obtained for values of these parameters well below those from earlier investigations. The values are, however, compatible to those found in proton-nucleus investigations. The values of best agreement do, however, for the one-dimensional model, depend upon the range of phase space where the comparison is made. For the three-dimensional model, the parameter values are less sensitive to the range considered.

Multiple muons in the Utah detector. II. Comparison with a hadronic scaling model

Detailed predictions are made for the multiple-muon-event rates measured in the underground muon experiment at the University of Utah. In our calculations, Feynman scaling is used to project inclusive proton-nucleus particle production cross sections from 19.2-GeV accelerator measurements to the ultrahigh-energy region from 1 TeV to 10 000 TeV. The multiplicity distribution is assumed to follow Koba-Nielsen-Olesen scaling. The primary cosmic-ray spectrum and composition are extrapolated upwards from the direct measurements made at less than a few TeV. Rates are calculated for detected multiplicities ${n}_{D}=1\ensuremath{-}30$ observed over a zenith angle range 30\ifmmode^\circ\else\textdegree\fi{}-72\ifmmode^\circ\else\textdegree\fi{} and over a depth range of 1.5\ifmmode\times\else\texttimes\fi{}${10}^{5}$${\ensuremath{-}10}^{6}$ g ${\mathrm{cm}}^{\ensuremath{-}2}$. Good agreement between predictions and measurements has been obtained with scaling and such a simple extrapolation to higher energies of the directly measured primary spectrum and composition.

Inclusive strange particle production in π+p interactions at 16 GeV/c

The production of K S 0, Λ and Λ is measured in π +p reactions at 16 GeV/ c. The total strange particle cross section is found to be 4.0 ± 0.3 mb, about 20% of the inelastic cross section. Cross sections for single strange particles and for strange particle pairs are determined, both inclusively and as functions of the charged multiplicity. Relative production rates for different strange particle combinations are compared with the prediction of the isospin statistical model. Inclusive spectra for single particles are studied and it is found the K S 0 are produced mostly in the forward hemisphere, most probably by fragmentation of the incident pion into K K π . The Λ are mostly backwards, probably deriving from fragmentation of the proton into ΛK pairs. The Λ tend to be produced forwards, but evidence is found for central Λ Λ production. Distributions in rapidity of the Λ particles from π + p interactions are compared in terms of the factorisation hypothesis. Results are given on the Λ transversal polarisation.

On the factorization of the pomeranchuk singularity in the Mueller-Regge diagrams

It is shown that the j plane singularity (Pomeron) which leads to a rising total cross-section like ( ln s) ϵ , ϵ > 0. cannot be factorizable in the Mueller diagrams for inclusive production of particles with large rapidity differences. The relevance of this result for the theories of a renormalized Pomeron is discussed.

Monte Carlo calculation of hadronic cascades at high energy

The transport of particles and the transport and deposition of energy in matter by the hadronic cascade is calculated by a Monte Carlo method. The most important input data are absorption cross sections of high energy particles on nuclei and inclusive single particle production cross sections as well as other data related to the interactions of high energy particles with matter. We describe the method used to select random events which satisfy both the inclusive cross sections and energy conservation in each event. This method differs from the usual methods for sampling according to phase space, which are not applicable here. We discuss also the general structure of the Monte Carlo programmes. Such procedures are applied to calculate: (i) shielding requirements, induced radioactivity, direct radiation doses and radiation heating around high energy accelerators; (ii) the performance of total absorption detectors for hadrons and (iii) the modification of secondary particle production in targets due to the hadronic cascade in the target.

Thermodynamic inclusive single particle spectra and particle production ratios at the ISR

Two essential modifications of the thermodynamic single particle spectra using fireballs according to the strong bootstrap model are described: (i) An energy-dependent velocity weight function is introduced which leads to better agreement with the flat single particle spectra in the central region observed at the ISR. (ii) Heavy pair production is modified by producing the two particles in different steps of the decay chain of the fireballs. The fact that heavy fireballs are produced leads in the model to a natural understanding of the deviations from scaling behaviour in the central region of single particle spectra p + p → π +-, p or K − + anything between 20 GeV and ISR energies. The particle production ratios p /π −, K −/π −, π +/p, K +/p and p /p are compared to recent ISR data.