Inclusive Production Cross Section Research Articles

Muon-electron events in high-energy proton-proton collisions

We have searched for events in proton-proton collisions, at the CERN Intersecting Storage Rings, which contain a muon and an electron of opposite sign. Such events cannot come from the decay of a single vector meson or from the Drell-Yan process, but can comee from the semileptonic decays of a pair of charmed mesons. We find a signal of 32 ± 16 events. Assumming that the signal is caused by charmed meson pairs, and using a model for the p T and p L distribution of such pairs, we estimate the total inclusive charm production cross section in proton-proton collisions to be (70 ± 36) μb.

Inclusive production cross sections of resonances in 32 GeV/ c K +p interactions

The inclusive production of resonances is systematically studied in K +p interactions at 32 GeV/ c. Total production cross sections are given for three baryon resonances, five vector and three 2 + tensor mesons. We also compare the central and fragmentation components of the total production cross sections with quark model predictions.

Inclusive production of K ∗(890), Σ(1385) and S ∗(993) resonances in [formula omitted]p interactions at 12 GeV/ c incident momentum

The reactions pp → K ∗(890) X, pp →Σ ±(1385) X and pp → S ∗(993) X at 12 GeV/ c incident momentum have been studied using 19 000 events with a visible V 0 decay in BEBC. Inclusive production cross sections of these resonances as a function of transverse momentum and rapidity are presented. The contribution of annihilation to the production of the K ∗(890) is investigated from a comparison with the corresponding pp data.

Results of a beam dump experiment at the CERN SPS neutrino facility

We report results from a beam dump experiment that has been performed at the CERN SPS neutrino facility using the CDHS neutrino counter detector. Limits on dimuon and trimuon production by new penetrating neutral particles are given. A new source of prompt electron and muon neutrinos has been observed giving (1.2±0.4)× 10−7 νe or νμ per incident proton with neutrino angle smaller than 1.85 mrad and Eν > 20 GeV. If these prompt neutrinos are attributed to charmed meson pair production, the inclusive DD production cross section could be of the order of 30 ωb. If axions are existing their production rate relative to π0 mesons is found to be less than 0.5 × 10−8.

Measurement ofϕProduction in Proton-Nucleus Collisions at 400 GeV/c

We have measured the invariant cross section for inclusive phi production in proton-nucleus collisions at 400 GeV/c near Feynman chi = 0. For transverse momenta in the range between 0.8 and 3.5 GeV/c the ratio of the phi to ..pi../sup -/ rises from 1 to 7%. We also report on correlations with particles opposite the phi in the center-of-mass system as they relate to the Okubo-Zweig-Iizuka rule.

Inclusive production of neutral strange particles in 250-GeV/cπ−pinteractions

Neutral-strange-particle production has been studied in a 46000-picture exposure in the Fermilab 15-ft bubble chamber. Cross sections for inclusive production of ${K}_{s}^{0}$, $\ensuremath{\Lambda}$, and $\overline{\ensuremath{\Lambda}}$ are given and compared with data at lower energies. The ${K}_{s}^{0}$'s are produced principally in the central region of rapidity with a cross section which increases with energy. The $\ensuremath{\Lambda}$'s are produced principally by proton fragmentation, whereas the $\overline{\ensuremath{\Lambda}}$'s are centrally produced. Correlations of ${K}_{s}^{0}{\ensuremath{\pi}}^{+}$ and ${K}_{s}^{0}{K}_{s}^{0}$ are shown to be different from those for ${\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$.

Hadron production from a boiling quark soup: A thermodynamical quark model predicting particle ratios in hadronic collisions

We present a thermodynamical quark model which can predict cross sections for particle production in hadronic interactions at high energies. In this model a hadronic collision gives rise to a soup of quarks and antiquarks at some temperature kT ≃ 170 MeV. Results for inclusive meson production cross sections look promising in comparison with experiments. We give a formula for the inclusive cross section.

Adependence of large-momentum-transfer inclusive reactions

The large-momentum-transfer inclusive cross section for production of pions, protons, and kaons from nulcei is discussed in the framework of a multiple-scattering theory. We find that the A dependence seen in recent experiments can be explained by considering higher-order large-momentum-transfer reactions between the projectile and the nucleons. The theory has one parameter, which can be interpreted as the value of of p/sub perpendicular/ at which the exponential falloff of the elementary cross section changes to a more-slowly-falling form. It is found that the data can be with fitted first- and second-order terms only.

Experimental means for distinguishing models of large p⊥ inclusive scattering

The scaling behavior, and to some extent the magnitude, of the ratio γ π of large p ⊥ direct photon and pion inclusive production cross sections are shown to provide an excellent means of determining the fundamental mechanism of large p ⊥ scattering.

Nucleons produced in inelastic electron scattering with a deuterium target

We have measured at − k 2 = 0.6 (GeV/ c) 2 and W = 2.3 GeV the inclusive electroproduction cross sections for final-state neutrons and protons from a deuterium target. By comparison with previous data from a proton target, we present cross sections for inclusive nucleon production from neutrons which show great similarity to those from protons. There is evidence that ϱ 0 production is present with essentially the same strength as with a proton target.

Hyperon-initiated reactions at high energies

We present detailed estimates of the differential cross sections for hyperon-nucleon charge-exchange and strangeness-exchange reactions. Polarization and line-reversal systematics are discussed, and reasons for studying such reactions experimentally are explained. In addition, using triple-Regge techniques we estimate the cross sections for inclusive hyperon resonance production, and examine Feynman scaling for these processes.

Near threshold production of neutral pions by complex particles

Cross sections for the inclusive neutral pion production cross section have been measured for near threshold energy 3He particles on complex nuclei. The results of these measurements are of order 10 −36 cm 2/sr · MeV. The neutral pion cross section for 710 MeV 4He on 12C has been found to be comparable to the production cross section for nucleons, 10 −30 cm 2/sr · MeV. Comparisons are made with a naive model relating complex particle production to nucleon production of pions.

Weak and electromagnetic effects in large pT proton-proton collisions

The weak and electromagnetic contributions to the inclusive cross section for hadron production at large p T in proton ISR experiments are calculated using the parton model. When compared with extrapolations of recent strong interaction data, it is found that they overtake the strong cross section at large p T for beam energies of several hundred GeV at a cross section which might be accessible (assuming a reasonable W boson mass in the weak case). Further, the parity violating effects of the weak interaction are found to be large and thus in principle could give an unambigous signature to weakly produced events, using polarised beams.

Structure of final states with a high transverse momentum π0 in proton-proton collisions

We present a study of the final state structure in proton-proton collisions (√ s = 53 GeV) where a large transverse momentum π 0 ( p t > 2 GeV/ c) is produced at an angle of 90°. Charged secondaries have been detected and momentum analysed in the split field magnet detector at the CERN Intersecting Storage Rings. The large angular coverage of this detector extends over ±2.5 units of rapidity and ±30° of azimuth with respect to the trigger π 0, both towards and away from it. In each of these directions, where we observe similar strong correlations, we present charged particle distributions, in rapidity and momentum. In the hemisphere containing the trigger π 0 we have measured the cross section for inclusive production of large transverse momentum ϱ ± mesons. In the opposite hemisphere the data exhibit several features predicted by hard scattering quark-parton models: coplanarity and short-range rapidity correlation for the large transverse momentum secondaries as well as a transverse momentum sharing distribution similar to that observed in deep inelastic electro-production and in e +e − collisions.

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.

Limits on Charmed-Meson Production ine+e−Annihilation at 4.8-GeV Center-of-Mass Energy

Data from e/sup +/e/sup -/ annihilation into hadrons at 4.8 GeV center-of-mass energy were used to search for charmed mesons in the mass range 1.5 to 4.0 GeV/c/sup 2/. Narrow peaks in the invariant-mass distributions for K/sup - +/..pi../sup + -/, K/sup 0//sub s/..pi../sup +/..pi../sup -/, ..pi../sup +/..pi../sup -/, K/sup +/K/sup -/, K/sup - +/, ..pi../sup + -/..pi../sup + -/, K/sup 0//sub s/..pi../sup + -/, K/sup 0//sub s/K/sup + -/, and ..pi../sup +/..pi../sup -/..pi../sup + -/ were sought. Upper limits are presented for the inclusive production cross section times the branching ratio for charmed mesons having these decay modes. 2 figures, 1 table.

Final-state absorption in multiperipheral models

We study s-channel unitarity effects in multiperipheral production amplitudes due to final state particle rescattering. For non-diffractive events we show that — if the pomeron is required to have α (0) = 1 — the absorbed overlap function leads to σ in ∼ (ln s) η and forward peak shrinking as (ln s) ν similarly to Reggeon field theories. Inclusive many-particle distributions and production cross sections are calculated, and found to have logarithmic multiplicity and integrable, i.e., not very long-range, correlations in the inelastic component. The t-distribution for diffractive production of large masses is found to have no turnover at small t in the model, but the probability of large-gap events is damped by absorption, so that consistency with unitarity is achieved. By the same token the Finkelstein-Kajantie paradox is avoided and multiple diffractive events give at most a small intercept renormalization. A comparison of this s-channel point of view with reggeon field theory is also given.

Inclusive cross sections for pion and proton production by photons using collimated coherent bremsstrahlung

Cross sections for the inclusive processes $\ensuremath{\gamma}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}X \mathrm{and} \mathrm{pX}$ have been measured at the Stanford Linear Accelerator Center for linearly polarized photons of average energy 10 and 14 GeV. The kinematic range of detected particles was ${P}_{T}=0.15 \mathrm{to} 1.0$ GeV/c, $x=0 \mathrm{to} \ensuremath{-}0.32$ for pions and -0.3 to -0.8 for protons at 10 GeV; the 14-GeV data had measurements at $x=0$ for pions and $x\ensuremath{\approx}\ensuremath{-}0.3$ for protons. The experiment was carried out using collimated coherent bremsstrahlung from a thin diamond radiator and the SLAC 1.6-GeV/c spectrometer. The variation of the cross section, as a function of $x$ and ${P}_{T}$, shows a marked similarity to that observed for pion and proton production from $\mathrm{pp}$ collisions. Our results show little dependence of the pion invariant cross section on either energy or polarization. The $\frac{{\ensuremath{\pi}}^{+}}{{\ensuremath{\pi}}^{\ensuremath{-}}}$ ratio varies from 1.3 at $x=0 \mathrm{to} 1.75$ at $x=\ensuremath{-}0.32$.

Unified Description of Single-Particle Production inppCollisions

We show that over a very wide range of c.m. angles, energies, and transverse momenta, the invariant cross sections for inclusive production of hadrons in $\mathrm{pp}$ collisions show a very simple behavior when expressed in terms of a new radial scaling variable ${x}_{R}\ensuremath{\equiv}\frac{{p}^{*}}{{{p}_{max}}^{*}}$, where ${p}^{*}$ is the total c.m. momentum of the hadron.

Inclusive contributions to the rising inelastic proton - proton cross section

Attention is directed to the nonscaling behavior of inclusive cross sections which may accompany a rising inelastic proton-proton cross section. In particular it is pointed out that the observed "threshold rise" of the invariant inclusive cross section for antibaryon production toward its scaling limit in the CERN ISR energy region sets a mass scale similar to that observed in the rising total cross section.