51 research outputs found
Revisiting the 'LSND anomaly' II: critique of the data analysis
No full textThis paper, together with a preceding paper, questions the so-called "LSND anomaly": a 3.8 sigma excess of (nu) over bar (e) interactions over standard backgrounds, observed by the LSND Collaboration in a beam dump experiment with 800 MeV protons. That excess has been interpreted as evidence for the (nu) over bar (mu) -> (nu) over bar (e) oscillation in the Delta m(2) range from 0.2 eV(2) to 2 eV(2). Such a Delta m(2) 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 a preceding paper, it was concluded that the estimates of standard backgrounds must be significantly increased. In this paper, the LSND Collaboration's estimate of the number of (nu) over bar (e) interactions followed by neutron capture, and of its error, is questioned. The overall conclusion is that the significance of the "LSND anomaly" is not larger than 2.3 sigm
Cross-sections of large-angle hadron production in proton- and pion-nucleus interactions VII: tin nuclei and beam momenta from \pm3 GeV/c to \pm15 GeV/c
No full textWe report on double-differential inclusive cross-sections of the production of secondary protons, charged pions, and deuterons, in the interactions with a 5% lambda(int) thick stationary tin target, of proton and pion beams with momentum from +/- 3 GeV/c to +/- 15 GeV/c. Results are given for secondary particles with production angles 20 degrees < theta < 125 degrees. Cross-sections on tin nuclei are compared with cross-sections on beryllium, carbon, copper, tantalum and lead nuclei
Cross-sections of large-angle hadron production in proton-and pion-nucleus interactions VIII: Aluminium nuclei and beam momenta from ±3 GeV/c to ±15 GeV/c
No full textWe report on double-differential inclusive crosssections of the production of secondary protons, charged pions, and deuterons, in the interactions with a 5% λint thick stationary aluminium target, of proton and pion beams with momentum from ±3 GeV/c to ±15 GeV/c. Results are given for secondary particles with production angles 20° < θ < 125°. Cross-sections on aluminium nuclei are compared with cross-sections on beryllium, carbon, copper, tin, tantalum and lead nuclei. © The Author(s) 2012
Revisiting the 'LSND anomaly' I: impact of new data
No full textThis paper, together with a subsequent paper, questions the so-called "LSND anomaly": a 3.8 sigma excess of (nu) over bar (e) interactions over standard backgrounds, observed by the LSND Collaboration in a beam dump experiment with 800 MeV protons. That excess has been interpreted as evidence for the (nu) over bar (mu) -> (nu) over bar (e) oscillation in the Delta m(2) range from 0.2 eV(2) to 2 eV(2). Such a Delta m(2) 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 Collaboration's data analysis will be questioned, rendering a further reduction of the significance of the "LSND anomaly"
{Rebuttal to: Comments on 'The HARP Time Projection Chamber: Characteristics and physics performance'}
No full textReply to 'Corrections to the HARP-CDP Analysis of the LSND Neutrino Oscillation Backgrounds'
No full textThe alleged mistakes in recent papers that reanalyze the backgrounds to the 'LSND anomaly' do not exist. We maintain our conclusion that the significance of the 'LSND anomaly' is not 3.8 sigma but not larger than 2.3 sigma.The alleged mistakes in recent papers that reanalyze the backgrounds to the 'LSND anomaly' do not exist. We maintain our conclusion that the significance of the 'LSND anomaly' is not 3.8 sigma but not larger than 2.3 sigma
HARP-CDP hadroproduction data: Comparison with FLUKA and GEANT4 simulations
No full textWe 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 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
Cross-sections of large-angle hadron production in proton- and pion-nucleus interactions VI: Carbon nuclei and beam momenta from ±3 GeV/c to ±15 GeV/c
No full textWe report on double-differential inclusive cross-sections of the production of secondary protons, charged pions, and deuterons, in the interactions with a 5% lambda (int) thick stationary carbon target, of proton and pion beams with momentum from +/- 3 GeV/c to +/- 15 GeV/c. Results are given for secondary particles with production angles 20A degree
Cross-sections of large-angle hadron production in proton- and pion-nucleus interactions I: Beryllium nuclei and beam momenta of +8.9 GeV/c and -8.0 GeV/c
No full textWe 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% λ abs thick stationary beryllium target, of a +8.9 GeV/c proton and pion beam, and a -8.0 GeV/c pion beam. Results are given for secondary particles with production angles 20 °<θ<125°. © 2009 Springer-Verlag
The Harp Time Projection Chamber: Characteristics and Physics Performance
No full textThe HARP spectrometer that took data at the CERN Proton Synchrotron in 2001 and 2002 had as large-angle detector system a Time Projection Chamber (TPC) surrounded by Resistive Plate Chambers. The design of the TPC, experience with its operation, and its good physics performance are described. The successful recovery from track distortions arising from inhomogeneities of the electric and magnetic fields in the TPC volume is discussed
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