53 research outputs found
Revisiting the 'LSND anomaly' II: critique of the data analysis
This paper, together with a preceding paper, questions the so-called 'LSND
anomaly': a 3.8 sigma excess of antielectronneutrino 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
antimuonneutrino to antielectronneutrino oscillation in the \Deltam2 range from
0.2 eV2 to 2 eV2. Such a \Deltam2 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 antielectronneutrino 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 sigma.Comment: 30 pages, 16 figures, 6 table
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
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 momentum 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.Comment: 68 pages, 13 figure
Fraction of muons in the T9 pion beams
In the T9 beam line, the beam instrumentation does not permit the separation of pions from muons. For a correct pion interaction cross-section, the flux of beam muons must be subtracted from the flux of pion-like particles incident on the target. In this memo, data from the beam instrumentation and the beam-muon identifier in 'empty-target' runs are analyzed in order to measure the fraction of beam muons incident on the target, in the pion beams from 3 to 15 GeV/c
Comparison of Geant4 hadron generation with data from the interactions with beryllium nuclei of +8.9 GeV/c protons and pions, and of -8 GeV/c pions
Hadron generation in the Geant4 simulation tool kit is compared with
inclusive spectra of secondary protons and pions from the interactions with
beryllium nuclei of +8.9 GeV/c protons and pions, and of -8.0 GeV/c pions. The
data were taken in 2002 at the CERN Proton Synchrotron with the HARP
spectrometer. We report on significant disagreements between data and simulated
data especially in the polar-angle distributions of secondary protons and
pions.Comment: 15 pages, 13 figure
Cross-Sections of Large-Angle Hadron Production in Proton- and Pion-Nucleus Interactions V: Lead Nuclei and Beam Momenta from +/-3 Gev/c to +/-15 Gev/c
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 momentum 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.Comment: 67 pages, 13 figures, 47 table
Cross-sections of large-angle hadron production in proton- and pion-nucleus interactions VI: carbon nuclei and beam momenta from \pm 3 GeV/c to \pm 15 GeV/c
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 momentum 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.Comment: 67 pages, 13 figure
Comments on TPC and RPC calibrations reported by the HARP Collaboration
The HARP Collaboration recently published calibrations of their TPC and RPC
detectors, and differential cross-sections of large-angle pion production in
proton-nucleus collisions. We argue that these calibrations are biased and
cross-sections based on them should not be trusted.Comment: 17 pages, 13 figure
The HARP Resistive Plate Chambers: Characteristics and Physics Performance
The HARP Resistive Plate Chamber (RPC) system was designed for time-of-flight measurement in the large-angle acceptance region of the HARP spectrometer. It comprised 46 four-gap glass RPCs covering an area of _8m2. The design of the RPCs, their operation, intrinsic properties, and system performance are described. The intrinsic time resolution of the RPCs is better than 130 ps leading to a system time resolution of _175 ps
Cross-Sections of Large-Angle Hadron Production in Proton- and Pion-Nucleus Interactions III: Tantalum Nuclei and Beam Momenta from +/-3 Gev/c to +/-15 Gev/c
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 tantalum 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 between 20 and 125 degrees. They are
of particular relevance for the optimization of the design parameters of the
proton driver of a neutrino factory.Comment: 68 pages, 12 figures, corrections in v2: added 'HARP -CDP group' to
author name, corrected two typos in Table 4 (last two p values for 65-90
degrees were all 0.972
The HARP Time Projection Chamber: Characteristics and Physics Performance
The 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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