The COHERENT Collaboration searched for scalar dark matter particles produced at the Spallation Neutron Source with masses between 1 and 220 MeV/c^{2} using a CsINa scintillation detector sensitive ...to nuclear recoils above 9 keV_{nr}. No evidence for dark matter is found and we thus place limits on allowed parameter space. With this low-threshold detector, we are sensitive to coherent elastic scattering between dark matter and nuclei. The cross section for this process is orders of magnitude higher than for other processes historically used for accelerator-based direct-detection searches so that our small, 14.6 kg detector significantly improves on past constraints. At peak sensitivity, we reject the flux consistent with the cosmologically observed dark-matter concentration for all coupling constants α_{D}<0.64, assuming a scalar dark-matter particle. We also calculate the sensitivity of future COHERENT detectors to dark-matter signals which will ambitiously test multiple dark-matter spin scenarios.
Using an 185-kg NaITl array, COHERENT has measured the inclusive electron-neutrino chargedcurrent cross section on 127I with pion decay-at-rest neutrinos produced by the Spallation Neutron Source at ...Oak Ridge National Laboratory. Iodine is one the heaviest targets for which low-energy (≤ 50 MeV) inelastic neutrino-nucleus processes have been measured, and this is the first measurement of its inclusive cross section. After a five-year detector exposure, COHERENT reports a flux-averaged cross section for electron neutrinos of ${9.2}_{—1.8}^{+2.1}$ × 10—40 cm2. This corresponds to a value that is ~41% lower than predicted using the MARLEY event generator with a measured Gamow-Teller strength distribution. In addition, the observed visible spectrum from charged-current scattering on 127I has been measured between 10 and 55 MeV, and the exclusive zero-neutron and one-or-more-neutron emission cross sections are measured to be ${5.2}_{—3.1}^{+3.4}$ × 10—40 and ${2.2}_{—2.2}^{+3.5}$ × 10—40 cm2, respectively.
Background and purpose
The aim was to determine the genetic background of unknown muscular dystrophy in five French families.
Methods
Twelve patients with limb girdle muscular dystrophy or distal ...myopathy were clinically evaluated. Gene mutations were identified using targeted exon sequencing and mutated DNAJB6 was tested in vitro.
Results
Five patients presented with distal lower limb weakness whilst others had proximal presentation with a variable rate of progression starting at the mean age of 38.5 years. Two novel mutations (c.284A>T, p.Asn95Ile, two families; and c.293_295delATG, p.Asp98del, one family) as well as the previously reported c.279C>G (p.Phe93Leu, two families) mutation in DNAJB6 were identified. All showed a reduced capacity to prevent protein aggregation.
Conclusions
The mutational and phenotypical spectrum of DNAJB6‐caused muscle disease is larger than previously reported, including also dysphagia. The originally reported c.279C>G (p.Phe93Leu) mutation is now identified in four different populations and appears to be a mutational hotspot. Our report confirms that some DNAJB6 mutations cause distal‐onset myopathy and hence DNAJB6 defects should be considered broadly in dominant muscular dystrophy families.
We describe a modular apparatus for use in parity-violation measurements in epithermal neutron–nucleus resonances with high instantaneous neutron fluxes at the Manuel Lujan Jr. Neutron Scattering ...Center at Los Alamos National Laboratory. This apparatus is designed to conduct high-precision measurements of the parity-odd transmission asymmetry of longitudinally polarized neutrons through targets containing nuclei with p-wave neutron–nucleus resonances in the 0.1–10 eV energy regime and to accommodate a future search for time reversal violation in polarized neutron transmission through polarized nuclear targets. The apparatus consists of an adjustable neutron and gamma collimation system, a 3He-4He ion chamber neutron flux monitor, two identical cryostats for target cooling, an adiabatic eV-neutron spin flipper, a near-unit efficiency 6Li-7Li scintillation detector operated in current mode, a flexible CAEN data acquisition system, and a neutron spin filter based on spin-exchange optical pumping of 3He gas. We describe the features of the apparatus design devoted to the suppression of systematic errors in parity-odd asymmetry measurements. We describe the configuration of the apparatus used to conduct a precision measurement of parity violation at the 0.7 eV p-wave resonance in 139La which employs two identical 139La targets, one to polarize the beam on the p-wave resonance using the weak interaction and one to analyze the polarization.
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