A Study of Strange Particle Production in Muon Neutrino Charged Current Interactions in the NOMAD Experiment

A study of strange particle production in muon neutrino charged current interactions has been performed using the data from the NOMAD experiment. Yields of neutral strange particles K0s, Lambda, AntiLambda have been measured. Mean multiplicities are reported as a function of the event kinematic variables Enu, W2 and Q2 as well as of the variables describing particle behaviour within a hadronic jet: xF, z and pT2. Decays of resonances and heavy hyperons with identified K0s and Lambda in the final state have been analyzed. Clear signals corresponding to K*+-, Sigma*+-, Xi- and Sigma0 have been observed.Comment: 43 pages, accepted for publication in the Nuclear Physics B as a Rapid Communication in Experimental High-Energy Physic

Perspectives and challenges for the use of radar in biological conservation

Radar is at the forefront for the study of broad-scale aerial movements of birds, bats and insects and related issues in biological conservation. Radar techniques are especially useful for investigating species which fly at high altitudes, in darkness, or which are too small for applying electronic tags. Here, we present an overview of radar applications in biological conservation and highlight its future possibilities. Depending on the type of radar, information can be gathered on local- to continental-scale movements of airborne organisms and their behaviour. Such data can quantify flyway usage, biomass and nutrient transport (bioflow), population sizes, dynamics and distributions, times and dimensions of movements, areas and times of mass emergence and swarming, habitat use and activity ranges. Radar also captures behavioural responses to anthropogenic disturbances, artificial light and man-made structures. Weather surveillance and other long-range radar networks allow spatially broad overviews of important stopover areas, songbird mass roosts and emergences from bat caves. Mobile radars, including repurposed marine radars and commercially dedicated ‘bird radars’, offer the ability to track and monitor the local movements of individuals or groups of flying animals. Harmonic radar techniques have been used for tracking short-range movements of insects and other small animals of conservation interest. However, a major challenge in aeroecology is determining the taxonomic identity of the targets, which often requires ancillary data obtained from other methods. Radar data have become a global source of information on ecosystem structure, composition, services and function and will play an increasing role in the monitoring and conservation of flying animals and threatened habitats worldwide

COHERENT PRODUCTION OF pi+ pi- MESONS BY CHARGED CURRENT INTERACTIONS OF NEUTRINOS AND ANTI-NEUTRINOS ON NEON NUCLEI AT THE TEVATRON

Coherent single-pion production on neon nuclei is studied using the Fermilab 15-ft bubble chamber filled with a heavy Ne-H2 mixture and exposed to the Tevatron neutrino beam. In the neutrino energy range 40ε300 GeV, the net signal is 20±6 events, giving a corrected rate per charged-current event of (0.26±0.10)%. The cross section and kinematic distributions agree with the predictions of a model based on partial conservation of axial-vector current and meson dominance. © 1989 The American Physical Society.0SCOPUS: ar.jinfo:eu-repo/semantics/publishe

The GENIE neutrino Monte Carlo generator

GENIE is a new neutrino event generator for the experimental neutrino physics community. The goal of the project is to develop a `canonical' neutrino interaction physics Monte Carlo whose validity extends to all nuclear targets and neutrino flavors from MeV to PeV energy scales. Currently, emphasis is on the few-GeV energy range, the challenging boundary between the non-perturbative and perturbative regimes, which is relevant for the current and near future long-baseline precision neutrino experiments using accelerator-made beams. The design of the package addresses many challenges unique to neutrino simulations and supports the full life-cycle of simulation and generator-related analysis tasks. GENIE is a large-scale software system, consisting of 120,000 lines of C++ code, featuring a modern object-oriented design and extensively validated physics content. The first official physics release of GENIE was made available in August 2007, and at the time of the writing of this article, the latest available version was v2.4.4.Comment: 36 pages, 6 figures, submitted to Nucl.Instrum.Meth.

Neutral Strange Particle Production in Neutrino and Antineutrino Charged-Current Interactions on Neon

A study has been made of neutral strange particle production in νμNe and ν̄μNe charged-current interactions at a higher energy than any previous study. The experiment was done at the Fermilab Tevatron using the 15-ft. bubble chamber, and the data sample consists of 814(154) observed neutral strange particles from 6263(1115) ν(ν̄) charged-current events. For the ν beam (average event energy Eν=150 GeV), the average multiplicities per charged-current event have been measured to be 0.408±0.048 for K0, 0.127±0.014 for Λ, and 0.015±0.005 for Λ̄, which are significantly greater than for lower-energy experiments. The dependence of rates on kinematical variables has been measured, and shows that both K0 and Λ production increase strongly with Eν, W2, Q2, and yB. Compared to lower-energy experiments, single-particle distributions indicate that there is much more K0 production for xF>-0.2, and the enhanced Λ production spans most of the kinematic region. Λ̄ production is mostly in the region xF-0.2 there is a significant excess of Λ production over the model's prediction. The Λ hyperons are found to be polarized in the production plane. © 1994 The American Physical Society.086 auteursSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Strangeness production in deep inelastic positron - proton scattering at HERA

Measurements are presented of $K^0$ meson and $\Lambda$ baryon production in deep-inelastic positron-proton scattering (DIS) in the kinematic range $10 < Q^2 < 70$GeV$^2$ and $10^{-4} < x < 10^{-2}$. The measurements, obtained using the H1 detector at the HERA collider, are discussed in the light of possible mechanisms for increased strangeness production at low Bjorken-$x$. Comparisons of the $x_F$ spectra, where $x_F$ is the fractional longitudinal momentum in the hadronic centre-of-mass frame, with results from electron-positron annihilation are made. The $x_F$ spectra and the $K^0$ ``seagull'' plot are compared with previous DIS results. The mean $K^0$ and $\Lambda$ multiplicities are studied as a function of the centre-of-mass energy $W$ and are observed to be consistent with a logarithmic increase with $W$ when compared with previous measurements. A comparison of the levels of strangeness production in diffractive and non-diffractive DIS is made. An upper limit of $0.9$nb, at the 95% confidence level, is placed on the cross-section for QCD instanton induced events.Comment: 36 pages, latex, 15 Figure

Dimuon Production by Neutrinos in the Fermilab 15 ft. Bubble Chamber at the Tevatron

The Fermilab 15-ft bubble chamber has been exposed to a quadrupole triplet neutrino beam produced at the Tevatron. The ratio of to in the beam is approximately 2.5. The mean event energy for -induced charged-current events is 150 GeV, and for -induced charged-current events it is 110 GeV. A total of 64 dimuon candidates (1+, 52 -+ and -, and 11 --) is observed in the data sample of approximately 13 300 charged-current events. The number and properties of the -- and + candidates are consistent with their being produced by background processes, the important sources being and K decay and punchthrough. The 90%-C.L. upper limit for --/- for muon momenta above 4 GeV/c is 1.2×10-3, and for momenta above 9 GeV/c this limit is 1.1×10-3. The opposite-sign-dimuono single-muon ratio is (0.62±0.13)% for muon momenta above 4 GeV/c. There are eight neutral strange particles in the opposite-sign sample, leading to a rate per dimuon event of 0.65±0.29. The opposite-sign-dimuon sample is consistent with the hypothesis of charm production and decay. © 1990 The American Physical Society.079 auteursSCOPUS: ar.jinfo:eu-repo/semantics/publishe