101 research outputs found
Search for nu(mu)-->nu(e) Oscillations in the NOMAD Experiment
We present the results of a search for nu(mu)-->nu(e) oscillations in the
NOMAD experiment at CERN. The experiment looked for the appearance of nu(e) in
a predominantly nu(mu) wide-band neutrino beam at the CERN SPS. No evidence for
oscillations was found. The 90% confidence limits obtained are delta m^2 < 0.4
eV^2 for maximal mixing and sin^2(2theta) < 1.4x10^{-3} for large delta m^2.
This result excludes the LSND allowed region of oscillation parameters with
delta m^2 > 10 eV^2.Comment: 19 pages, 8 figures. Submitted to Phys. Lett.
Search for the exotic resonance in the NOMAD experiment
A search for exotic Theta baryon via Theta -> proton +Ks decay mode in the
NOMAD muon neutrino DIS data is reported. The special background generation
procedure was developed. The proton identification criteria are tuned to
maximize the sensitivity to the Theta signal as a function of xF which allows
to study the Theta production mechanism. We do not observe any evidence for the
Theta state in the NOMAD data. We provide an upper limit on Theta production
rate at 90% CL as 2.13 per 1000 of neutrino interactions.Comment: Accepted to European Physics Journal
A Precise Measurement of the Muon Neutrino-Nucleon Inclusive Charged Current Cross-Section off an Isoscalar Target in the Energy Range 2.5 < E_\nu < 40 GeV by NOMAD
We present a measurement of the muon neutrino-nucleon inclusive charged
current cross-section, off an isoscalar target, in the neutrino energy range
GeV. The significance of this measurement is its
precision, % in GeV, and % in GeV regions, where significant uncertainties in previous
experiments still exist, and its importance to the current and proposed long
baseline neutrino oscillation experiments.Comment: 14 pages, 3 figures, submitted to Phys.Lett.
A Study of Strange Particles Produced in Neutrino Neutral Current Interactions in the NOMAD Experiment
Results of a detailed study of strange particle production in neutrino
neutral current interactions are presented using the data from the NOMAD
experiment. Integral yields of neutral strange particles (K0s, Lambda,
Lambda-bar) have been measured. Decays of resonances and heavy hyperons with an
identified K0s or Lambda in the final state have been analyzed. Clear signals
corresponding to K* and Sigma(1385) have been observed. First results on the
measurements of the Lambda polarization in neutral current interactions have
been obtained.Comment: Accepted for publication in Nuclear Physics B as a rapid
communicatio
A Measurement of Coherent Neutral Pion Production in Neutrino Neutral Current Interactions in NOMAD
We present a study of exclusive neutral pion production in neutrino-nucleus
Neutral Current interactions using data from the NOMAD experiment at the CERN
SPS. The data correspond to muon-neutrino Charged Current
interactions in the energy range GeV. Neutrino
events with only one visible in the final state are expected to result
from two Neutral Current processes: coherent production, {\boldmath
} and single production in
neutrino-nucleon scattering. The signature of coherent production is an
emergent almost collinear with the incident neutrino while 's
produced in neutrino-nucleon deep inelastic scattering have larger transverse
momenta. In this analysis all relevant backgrounds to the coherent
production signal are measured using data themselves. Having determined the
backgrounds, and using the Rein-Sehgal model for the coherent
production to compute the detection efficiency, we obtain {\boldmath } corrected coherent- events with GeV. We measure {\boldmath }.
This is the most precise measurement of the coherent production to
date.Comment: 23 pages, 9 figures, accepted for publication in Phys. Lett.
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Junior staffing changes and the temporal ecology of adverse incidents in acute psychiatric wards
Aim. This paper reports an examination of the relationship between adverse incident rates, the arrival of new junior staff on wards, and days of the week on acute psychiatric wards.
Background. Incidents of violence, absconding and self-harm in acute inpatient services pose risks to patients and staff. Previous research suggests that the arrival of inexperienced new staff may trigger more adverse incidents. Findings on the relationship between incidents and the weekly routine are inconsistent.
Method. A retrospective analysis was conducted of formally reported incident rates, records of nursing student allocations and junior doctor rotation patterns, using Poisson Regression. Variance between days of the week was explored using contingency table analysis. The data covered 30 months on 17 psychiatric wards, and were collected in 2002–2004.
Findings. The arrival of new and inexperienced staff on the wards was not associated with increases in adverse incident rates. Most types of incidents were less frequent at weekends and midweek. Incident rates were unchanged on ward-round days, but increased rates were found on the days before and after ward rounds.
Conclusion. Increased patient tension is associated with raised incident rates. It may be possible to reduce incident rates by moderating stimulation in the environment and by mobilizing support for patients during critical periods
Time-Dependent CP Violation Effects in Partially Reconstructed Decays
We report measurements of time-dependent decay rates for decays and extraction of CP violation parameters related to .
We use a partial reconstruction technique, whereby signal events are identified
using information only from the primary pion and the charged pion from the
decay of the . The analysis uses of data
accumulated at the resonance with the Belle detector at the KEKB
asymmetric-energy collider. We measure the CP violation parameters
and .Comment: 15 pages, 5 figures. To appear in Physics Letters
Bose-Einstein correlations in charged current muon-neutrino interactions in the NOMAD experiment at CERN
Bose-Einstein correlations in one and two dimensions have been studied, with high statistics, in charged current muon-neutrino interaction events collected with the NOMAD detector at CERN. In one dimension the Bose-Einstein effect has been analyzed with the Goldhaber and the Kopylov-Podgoretskii phenomenological parametrizations. The Goldhaber parametrization gives the radius of the pion emission region R-G = 1.01 +/- 0.05(stat)(-0.06)(+0,09)(sys) fm and for the chaoticity parameter the value lambda = 0.40 +/- 0.03(stat)(-0.06)(+0.01) (sys). Using the Kopylov-Podgoretskii parametrization yields R-KP = 2.07 +/- 0.04(stat)(-0.14)(+0.01) (sys) fm and lambda(KP) = 0.29 +/- 0.06(stat)(-0.04)(+0,01) (sys) Different parametrizations of the long-range correlations have been also studied. The two-dimensional shape of the source has been investigated in the longitudinal comoving frame. A significant difference between the transverse and the longitudinal dimensions is observed. The high statistics of the collected sample allowed the study of the Bose-Einstein correlations as a function of rapidity, charged particle multiplicity and hadronic energy. A weak dependence of both radius and chaoticity on multiplicity and hadronic energy is found
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