A new measurement of the branching ratio R_{e/μ}=Γ(π^{+}→e^{+}ν+π^{+}→e^{+}νγ)/Γ(π^{+}→μ^{+}ν+π^{+}→μ^{+}νγ) resulted in R_{e/μ}^{exp}=1.2344±0.0023(stat)±0.0019(syst)×10^{-4}. This is in agreement ...with the standard model prediction and improves the test of electron-muon universality to the level of 0.1%.
A search for massive neutrinos has been made in the decay π+→e+ν. No evidence was found for extra peaks in the positron energy spectrum indicative of pion decays involving massive neutrinos (π→e+νh). ...Upper limits (90% C.L.) on the neutrino mixing matrix element |Uei|2 in the neutrino mass region 60–135 MeV/c2 were set and are an order of magnitude improvement over previous results.
The three body pion decays ... where X is a weakly interacting neutral boson, were searched for using the full data set from the PIENU experiment. An improved limit on ... in the mass range ... and a ...first result for ... in the region ... were obtained. The Majoron-neutrino coupling model was also constrained using the current experimental result of the ... branching ratio.(ProQuest: ... denotes formulae omitted.)
Charged lepton flavor violating muon decay μ+ → e+XH, where XH is a massive neutral boson, was sought by searching for extra peaks in the muon decay μ+ → e+ν¯ν energy spectrum in the mXH mass region ...47.8–95.1 MeV/c2. No signal was found and 90% confidence level upper limits were set on the branching ratio Γ(μ+ → e+XH)/Γ(μ+ → e+ν¯ν) at the level of 10−5 for this region.
Neutrino oscillation experiments require a precise measurement of the neutrino energy. However, the kinematic detection of the final-state neutron in the neutrino interaction is missing in current ...neutrino oscillation experiments. The missing neutron kinematic detection results in a smaller detected neutrino energy than the true neutrino energy. A novel 3D-projection scintillator tracker, which consists of roughly ten million active cubes covered with an optical reflector, is capable of measuring the neutron kinetic energy and direction on an event-by-event basis using the time-of-flight technique thanks to the fast timing, fine granularity, and high light yield. The $\overline{v}$μ interactions tend to produce neutrons in the final state. By measuring the neutron kinetic energy, the $\overline{v}$μ energy can be reconstructed better, allowing a tighter incoming neutrino flux constraint. This article shows the detector's ability to reconstruct neutron kinetic energy and the $\overline{v}$μ flux constraint achieved by selecting the charged-current interactions without mesons or protons in the final state.
Abstract
The ability of free electrons to drift long distances at
high velocities in pure liquid argon under an applied electric field
has been exploited for the past forty years to implement ...detectors
with increasingly larger volumes for high energy physics research.
The attachment of free electrons to impurities in the LAr is an
important limit on the free instrumented volume of these extremely
large detectors, and impurity concentrations as small as 100 ppt can
reduce their resolution and efficiency. In this paper, we summarize
the electron attachment rate constants as a function of the applied
electric field, for common impurities in LArTPCs, obtained from data
in the literature. We further provide analytical functions to
parameterize the data, which are useful to compare with new
measurements, to model and analyze the performance of existing
detectors, and to predict the performance of new detectors.
We characterised Water-based Liquid Scintillator (WbLS) using low energy protons, UV-VIS absorbance, and fluorescence spectroscopy. We have also developed and validated a simulation model that ...describes the behaviour of WbLS in our detector configurations for proton beam energies of 210 MeV, 475 MeV, and 2 GeV and for two WbLS compositions. These results have enabled us to estimate the light yield and ionisation quenching of WbLS, as well as to understand the influence of the wavelength shifting of Cherenkov light on our measurements. These results are relevant to the suitability of WbLS materials for next generation intensity frontier experiments.
Abstract
Liquid Argon Time Projection Chamber (LArTPC) technology is commonly utilized in neutrino
detector designs. It enables detailed reconstruction of neutrino events with high spatial
precision ...and low energy threshold. Its field response (FR) model describes the time-dependent
electric currents induced in the anode-plane electrodes when ionization electrons drift nearby. An
accurate and precise FR is a crucial input to LArTPC detector simulations and charge
reconstruction. Established LArTPC designs have been based on parallel wire planes. It allows
accurate and computationally economic two-dimensional (2D) FR models utilizing the translational
symmetry along the direction of the wires. Recently, novel LArTPC designs utilize electrodes
formed on printed circuit board (PCB) in the shape of strips with through holes. The translational
symmetry is no longer a good approximation near the electrodes and a new FR calculation that
employs regions with three dimensions (3D) has been developed. Extending the 2D models to 3D would
be computationally expensive. Fortuitously, the nature of strips with through holes allows for a
computationally economic approach based on the finite-difference method (FDM). In this paper, we
present a new software package
pochoir
that calculates LArTPC field response for these new
strip-based anode designs. This package combines 3D calculations in the volume near the electrodes
with 2D far-field solutions to achieve fast and precise field response computation. We apply the
resulting FR to simulate and reconstruct samples of cosmic-ray muons and
39
Ar decays from a
Vertical Drift (VD) detector prototype operated at CERN. We find the difference between real and
simulated data within 5%. Current state-of-the-art LArTPC software requires a 2D FR which we
provide by averaging over one dimension and estimate that variations lost in this average are
smaller than 7%.
A new water-based liquid scintillator and potential applications Yeh, M.; Hans, S.; Beriguete, W. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2011, Letnik:
660, Številka:
1
Journal Article
Recenzirano
In this paper we describe a new type of scintillating liquid based on water. We describe the concept, preparation, and properties of this liquid, and how it could be used for a very large, but ...economical detector. The applications of such a detector range from fundamental physics such as nucleon decay and neutrino physics to physics with broader application such as neutron detection. We briefly describe the scientific requirements of these applications, and how they can be satisfied by the new material.
We describe the design of a 20-liter test stand constructed to study fundamental properties of liquid argon (LAr). This system utilizes a simple, cost-effective gas argon (GAr) purification to ...achieve high purity, which is necessary to study electron transport properties in LAr. An electron drift stack with up to 25 cm length is constructed to study electron drift, diffusion, and attachment at various electric fields. A gold photocathode and a pulsed laser are used as a bright electron source. The operational performance of this system is reported.
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