147 research outputs found
Constraining short-range spin-dependent forces with polarized helium 3 at the Laue-Langevin Institute
We have searched for a short-range spin-dependent interaction mediated by a
hypothetical light scalar boson with CP-violating couplings to the neutron
using the spin relaxation of hyperpolarized He. The walls of the He
cell would generate a depolarizing pseudomagnetic field.Comment: Twelfth Conference on the Intersections of Particle and Nuclear
Physics (CIPANP2015), Vail Marriott Mountain Resort, Vail, Colorado, US
Re-entrant spin glass and magnetoresistance in Co_{0.2}Zn_{0.8}Fe_{1.6}Ti_{0.4}O_4 spinel oxide
We have investigated the static and dynamic response of magnetic clusters in
Co_{0.2}Zn_{0.8}Fe_{1.6}Ti_{0.4}O_4 spinel oxide, where a sequence of magnetic
phase transitions, i.e., paramagnetic (PM) to ferromagnetic at T_{C}
270K and ferromagnetic to canted spin glass state at T_f\leq$ 125K is
observed
Complete lung agenesis caused by complex genomic rearrangements with neo-TAD formation at the SHH locus
During human organogenesis, lung development is a timely and tightly regulated developmental process under the control of a large number of signaling molecules. Understanding how genetic variants can disturb normal lung development causing different lung malformations is a major goal for dissecting molecular mechanisms during embryogenesis. Here, through exome sequencing (ES), array CGH, genome sequencing (GS) and Hi-C, we aimed at elucidating the molecular basis of bilateral isolated lung agenesis in three fetuses born to a non-consanguineous family. We detected a complex genomic rearrangement containing duplicated, triplicated and deleted fragments involving the SHH locus in fetuses presenting complete agenesis of both lungs and near-complete agenesis of the trachea, diagnosed by ultrasound screening and confirmed at autopsy following termination. The rearrangement did not include SHH itself, but several regulatory elements for lung development, such as MACS1, a major SHH lung enhancer, and the neighboring genes MNX1 and NOM1. The rearrangement incorporated parts of two topologically associating domains (TADs) including their boundaries. Hi-C of cells from one of the affected fetuses showed the formation of two novel TADs each containing SHH enhancers and the MNX1 and NOM1 genes. Hi-C together with GS indicate that the new 3D conformation is likely causative for this condition by an inappropriate activation of MNX1 included in the neo-TADs by MACS1 enhancer, further highlighting the importance of the 3D chromatin conformation in human disease
First observation of cyclotron radiation from MeV-scale following nuclear beta decay
We present an apparatus for detection of cyclotron radiation that allows a
frequency-based beta energy determination in the 5 keV to 5 MeV range,
characteristic of nuclear beta decays. The cyclotron frequency of the radiating
beta particles in a magnetic field is used to determine the beta energy
precisely. Our work establishes the foundation to apply the cyclotron radiation
emission spectroscopy (CRES) technique, developed by the Project 8
collaboration, far beyond the 18-keV tritium endpoint region. We report initial
measurements of beta^-s from 6He and beta^+s from 19Ne decays to demonstrate
the broadband response of our detection system and assess potential systematic
uncertainties for beta spectroscopy over the full (MeV) energy range. This work
is an important benchmark for the practical application of the CRES technique
to a variety of nuclei, in particular, opening its reach to searches for
evidence of new physics beyond the TeV scale via precision beta-decay
measurements
Intelligent Assistant Language Understanding On Device
It has recently become feasible to run personal digital assistants on phones
and other personal devices. In this paper we describe a design for a natural
language understanding system that runs on device. In comparison to a
server-based assistant, this system is more private, more reliable, faster,
more expressive, and more accurate. We describe what led to key choices about
architecture and technologies. For example, some approaches in the dialog
systems literature are difficult to maintain over time in a deployment setting.
We hope that sharing learnings from our practical experiences may help inform
future work in the research community
Characterization of Charge Spreading and Gain of Encapsulated Resistive Micromegas Detectors for the Upgrade of the T2K Near Detector Time Projection Chambers
An upgrade of the near detector of the T2K long baseline neutrino oscillation
experiment is currently being conducted. This upgrade will include two new Time
Projection Chambers, each equipped with 16 charge readout resistive Micromegas
modules. A procedure to validate the performance of the detectors at different
stages of production has been developed and implemented to ensure a proper and
reliable operation of the detectors once installed. A dedicated X-ray test
bench is used to characterize the detectors by scanning each pad individually
and to precisely measure the uniformity of the gain and the deposited energy
resolution over the pad plane. An energy resolution of about 10% is obtained. A
detailed physical model has been developed to describe the charge dispersion
phenomena in the resistive Micromegas anode. The detailed physical description
includes initial ionization, electron drift, diffusion effects and the readout
electronics effects. The model provides an excellent characterization of the
charge spreading of the experimental measurements and allowed the simultaneous
extraction of gain and RC information of the modules
Analysis of test beam data taken with a prototype of TPC with resistive Micromegas for the T2K Near Detector upgrade
In this paper we describe the performance of a prototype of the High Angle
Time Projection Chambers (HA-TPCs) that are being produced for the Near
Detector (ND280) upgrade of the T2K experiment. The two HA-TPCs of ND280 will
be instrumented with eight Encapsulated Resistive Anode Micromegas (ERAM) on
each endplate, thus constituting in total 32 ERAMs. This innovative technique
allows the detection of the charge emitted by ionization electrons over several
pads, improving the determination of the track position. The TPC prototype has
been equipped with the first ERAM module produced for T2K and with the HA-TPC
readout electronics chain and it has been exposed to the DESY Test Beam in
order to measure spatial and dE/dx resolution. In this paper we characterize
the performances of the ERAM and, for the first time, we compare them with a
newly developed simulation of the detector response. Spatial resolution better
than 800 and dE/dx resolution better than 10% are observed for
all the incident angles and for all the drift distances of interest. All the
main features of the data are correctly reproduced by the simulation and these
performances fully fulfill the requirements for the HA-TPCs of T2K
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