This paper, together with a subsequent paper, questions the so-called LSND anomaly: a 3.8 {sigma} excess of anti-electronneutrino interactions over standard backgrounds, observed by the LSND Collaboration in a beam dump experiment with 800 MeV proton
s. That excess has been interpreted as evidence for the anti-muonneutrino{to} anti-electronneutrino oscillation in the {Delta}m2 range from 0.2 eV2 to 2 eV2. Such a {Delta}m2 range is incompatible with the widely accepted model of oscillations between three light neutrino species and would require the existence of at least one light sterile neutrino. In this paper, new data on pion production by protons on nuclei are presented, and four decades old data on pion production by neutrons on nuclei are recalled, that together increase significantly the estimates of standard backgrounds in the LSND experiment, and decrease the significance of the LSND anomaly from 3.8 {sigma} to 2.9 {sigma}. In a subsequent paper, in addition the LSND Collaborations data analysis will be questioned, rendering a further reduction of the significance of the LSND anomaly.
We report on double-differential inclusive cross-sections of the production of secondary protons, charged pions, and deuterons, in the interactions with a 5% nuclear interaction length thick stationary tin target, of proton and pion beams with moment
um from pm3 GeV/c to pm15 GeV/c. Results are given for secondary particles with production angles between 20 and 125 degrees. Cross-sections on tin nuclei are compared with cross-sections on beryllium, carbon, copper, tantalum and lead nuclei.
We report on double-differential inclusive cross-sections of the production of secondary protons, charged pions, and deuterons, in the interactions with a 5% nuclear interaction length thick stationary carbon target, of proton and pion beams with mom
entum from pm 3 GeV/c to pm 15 GeV/c. Results are given for secondary particles with production angles between 20 and 125 degrees. Cross-sections on carbon nuclei are compared with cross-sections on beryllium, copper, tantalum and lead nuclei.
We report on the comparison of production characteristics of secondary protons and charged pions in the interactions of protons and charged pions with momentum between 3 GeV/c and 15 GeV/c with beryllium, copper, and tantalum nuclei, with simulations
by the FLUKA and Geant4 Monte Carlo tool kits. Overall production cross-sections are reasonably well reproduced, within factors of two. In more detail, there are areas with poor agreement that are unsatisfactory and call for modelling improvements. Overall, the current FLUKA simulation fares better than the current Geant4 simulation.
We report on double-differential inclusive cross-sections of the production of secondary protons, charged pions, and deuterons, in the interactions with a 5% nuclear interaction length thick stationary lead target, of proton and pion beams with momen
tum from +/-3 GeV/c to +/-15 GeV/c. Results are given for secondary particles with production angles 20 to 125 degrees. Cross-sections on lead nuclei are compared with cross-sections on beryllium, copper, and tantalum nuclei.
We report on double-differential inclusive cross-sections of the production of secondary protons, charged pions, and deuterons, in the interactions with a 5% nuclear interaction length thick stationary copper target, of proton and pion beams with mom
entum from +/-3 GeV/c to +/-15 GeV/c. Results are given for secondary particles with production angles between 20 and 125 degrees.
We report on double-differential inclusive cross-sections of the production of secondary protons, deuterons, and charged pions and kaons, in the interactions with a 5% nuclear interaction length thick stationary beryllium target, of a +8.9 GeV/c prot
on and pion beam, and a -8.0 GeV/c pion beam. Results are given for secondary particles with production angles between 20 and 125 degrees.
The so-called LSND anomaly, a 3.8 sigma excess of anti-nu_e events interpreted as originating from anti-nu_mu -> anti-nu_e oscillation, gave rise to many theoretical speculations. The MiniBooNE Collaboration reported inconsistency of this interpretat
ion with the findings from their search for nu_mu -> nu_e oscillations. Yet the origin of the LSND anomaly was never clarified. A critical issue is the prediction of the background anti-nu_e flux that was used in the analysis of the LSND experiment. For this, decisive input comes from pion spectra measured with the HARP large-angle spectrometer under conditions that closely resemble the LSND situation: a proton beam with 800 MeV kinetic energy hitting a water target.
Hadron generation models are indispensable for the simulation and calibration of particle physics detectors. The models used by the Geant4 simulation tool kit are compared with inclusive spectra of secondary protons and pions from the interactions wi
th beryllium nuclei of +8.9 GeV/c protons and pions, and of -8.0 GeV/c pions. We report on significant disagreements between data and model predictions especially in the polar-angle distributions of secondary protons and pions.
Precise measurements of neutrino oscillation parameters and of neutrino-nucleon cross-sections require a good understanding of neutrino beams: flux as a function of energy, transverse beam profile, and flavour composition. For this, hadron production
spectra in proton-nucleus collisions are essential. We report on double-differential inclusive large-angle cross-sections of the production of secondary protons and charged pions, in the interactions with a 5% lambda thick stationary beryllium target, of proton and pion beams with momentum from 3 GeV/c to 15 GeV/c. Our results show cross-sections reported by the HARP Collaboration to be wrong by factors of up to two.
