101 research outputs found
Nuclear aspects of neutral current non-standard -nucleus reactions and the role of the exotic transitions experimental limits
The nuclear aspects of flavour changing neutral current (FCNC) processes,
predicted by various new-physics models to occur in the presence of nuclei, are
examined by computing the relevant nuclear matrix elements within the context
of the quasi-particle RPA using realistic strong two-body forces. One of our
aims is to explore the role of the non-standard interactions (NSI) in the
leptonic sector and specifically: (i) in lepton flavour violating (LFV)
processes involving the neutral particles and ,
and (ii) in charged lepton flavour violating (cLFV)
processes involving the charged leptons or . As concrete
nuclear systems we have chosen the stopping targets of
conversion experiments, i.e. the nucleus of the PRIME/PRISM
experiment at J-PARC and the of the COMET at J-PARC as well
as of the Mu2e at Fermilab. These experiments have been designed to reduce the
single event sensitivity down to -- in searching for
charged lepton mixing events. Our goal is, by taking advantage of our detailed
nuclear structure calculations and using the present limits or the sensitivity
of the aforementioned exotic experiments, to put
stringent constraints on the parameters of NSI Lagrangians.Comment: 8 pages, 4 figures, 3 Tables, Physics Letters B accepte
Neutrino transition magnetic moments within the non-standard neutrino-nucleus interactions
Tensorial non-standard neutrino interactions are studied through a combined
analysis of nuclear structure calculations and a sensitivity -type of
neutrino events expected to be measured at the COHERENT experiment, recently
planned to operate at the Spallation Neutron Source (Oak Ridge). Potential
sizeable predictions on transition neutrino magnetic moments and other
electromagnetic parameters, such as neutrino milli-charges, are also addressed.
The non-standard neutrino-nucleus processes, explored from nuclear physics
perspectives within the context of quasi-particle random phase approximation,
are exploited in order to estimate the expected number of events originating
from vector and tensor exotic interactions for the case of reactor neutrinos,
studied with TEXONO and GEMMA neutrino detectors.Comment: 7 pages, 6 Figures, 2 Tables, Accepted for publication to Physics
Letters
Probing neutrino transition magnetic moments with coherent elastic neutrino-nucleus scattering
We explore the potential of current and next generation of coherent elastic
neutrino-nucleus scattering (CENS) experiments in probing neutrino
electromagnetic interactions. On the basis of a thorough statistical analysis,
we determine the sensitivities on each component of the Majorana neutrino
transition magnetic moment (TMM), , that
follow from low-energy neutrino-nucleus experiments. We derive the sensitivity
to neutrino TMM from the first CENS measurement by the COHERENT
experiment, at the Spallation Neutron Source. We also present results for the
next phases of COHERENT using HPGe, LAr and NaI[Tl] detectors and for reactor
neutrino experiments such as CONUS, CONNIE, MINER, TEXONO and RED100. The role
of the CP violating phases in each case is also briefly discussed. We conclude
that future CENS experiments with low-threshold capabilities can improve
current TMM limits obtained from Borexino data.Comment: 25 pages, 8 figures, 2 tables, analysis updated; conclusions
unchanged; references added; matches published versio
Constraining nuclear physics parameters with current and future COHERENT data
Motivated by the recent observation of coherent elastic neutrino-nucleus
scattering (CENS) at the COHERENT experiment, our goal is to explore its
potential in probing important nuclear structure parameters. We show that the
recent COHERENT data offers unique opportunities to investigate the neutron
nuclear form factor. Our present calculations are based on the deformed Shell
Model (DSM) method which leads to a better fit of the recent CENS data,
as compared to known phenomenological form factors such as the Helm-type,
symmetrized Fermi and Klein-Nystrand. The attainable sensitivities and the
prospects of improvement during the next phase of the COHERENT experiment are
also considered and analyzed in the framework of two upgrade scenarios.Comment: 13 pages, 5 figures, 2 tables; v2: minor corrections, version to
appear in PL
Consequences of the Dresden-II reactor data for the weak mixing angle and new physics
The Dresden-II reactor experiment has recently reported a suggestive evidence
for the observation of coherent elastic neutrino-nucleus scattering, using a
germanium detector. Given the low recoil energy threshold, these data are
particularly interesting for a low-energy determination of the weak mixing
angle and for the study of new physics leading to spectral distortions at low
momentum transfer. Using two hypotheses for the quenching factor, we study the
impact of the data on: (i) The weak mixing angle at a renormalization scale of
, (ii) neutrino generalized interactions with light
mediators, (iii) the sterile neutrino dipole portal. The results for the weak
mixing angle show a strong dependence on the quenching factor choice. Although
still with large uncertainties, the Dresden-II data provide for the first time
a determination of at such scale using coherent elastic
neutrino-nucleus scattering data. Tight upper limits are placed on the light
vector, scalar and tensor mediator scenarios. Kinematic constraints implied by
the reactor anti-neutrino flux and the ionization energy threshold allow the
sterile neutrino dipole portal to produce up-scattering events with sterile
neutrino masses up to MeV. In this context, we find that limits are
also sensitive to the quenching factor choice, but in both cases competitive
with those derived from XENON1T data and more stringent that those derived with
COHERENT data, in the same sterile neutrino mass range.Comment: 11 pages, 5 figures. Statistical analysis improved; V3: matches
published version in JHE
Implications of the first detection of coherent elastic neutrino-nucleus scattering (CEvNS) with Liquid Argon
The CENNS-10 experiment of the COHERENT collaboration has recently reported
the first detection of coherent-elastic neutrino-nucleus scattering (CEvNS) in
liquid Argon with more than significance. In this work, we exploit
the new data in order to probe various interesting parameters which are of key
importance to CEvNS within and beyond the Standard Model. A dedicated
statistical analysis of these data shows that the current constraints are
significantly improved in most cases. We derive a first measurement of the
neutron rms charge radius of Argon, and also an improved determination of the
weak mixing angle in the low energy regime. We also update the constraints on
neutrino non-standard interactions, electromagnetic properties and light
mediators with respect to those derived from the first COHERENT-CsI data.Comment: discussion expanded including light mediators and nuclear
uncertainties, figures added, references added. V3: Fig. 7 corrected,
conclusions unchange
Light vector mediators facing XENON1T data
Recently the XENON1T collaboration has released new results on searches for
new physics in low-energy electronic recoils. The data shows an excess over
background in the low-energy tail, particularly pronounced at about keV.
With an exposure of tonne-year, large detection efficiency and energy
resolution, the detector is sensitive as well to solar neutrino backgrounds,
with the most prominent contribution given by neutrinos. We investigate
whether such signal can be explained in terms of new neutrino interactions with
leptons mediated by a light vector particle. We find that the excess is
consistent with this interpretation for vector masses below MeV.
The region of parameter space probed by the XENON1T data is competitive with
constraints from laboratory experiments, in particular GEMMA, Borexino and
TEXONO. However we point out a severe tension with astrophysical bounds and
cosmological observations.Comment: 6 pages, 4 figures. V3: Few typos corrected and one reference added.
Matches version published in PL
Facilitating mental health research for patients, clinicians and researchers: a mixed-method study
OBJECTIVES: Research registers using Consent for Contact (C4C) can facilitate recruitment into mental health research studies, allowing investigators to contact patients based on clinical records information. We investigated whether such a register was useful for mental health research, seeking the perspectives of patients and research investigators. SETTING AND DESIGN: In 2012, a C4C register was developed in a large secondary mental health provider within the UK; almost 9000 patients have joined. This mixed-method study audited the effectiveness of the register. PARTICIPANTS: A 'mystery shopper' exercise was conducted, and patients (n=21) were recruited to ask clinicians about the availability of research opportunities. Structured interviews were conducted with patients (n=52) about their experiences of being on the register. Similar interviews were conducted with 18 investigators from 19 studies, who had attempted to use the register to recruit participants. OUTCOME MEASURES: The impact of C4C on study recruitment, and whether it helped patients learn about research. RESULTS: So far, the register has provided 928 individuals with 1085 research opportunities (in 60% of cases, the individual agreed to participate in the study). Clinicians were willing to link patients to research opportunities, but often lacked information about studies. For patients, the register provided opportunities which they may not otherwise have; 27 of 52 had participated in studies since joining the register (18 participating for the first time). Most investigators used the register to supplement recruitment to their studies, but described problems in prescreening potential participants from a clinical record for complex studies. CONCLUSIONS: Although the register helped investigators recruit for studies, and provided patients with research opportunities, clinicians' input is still useful for identifying suitable participants. C4C registers should be adapted to provide clinicians with automatically updated information on local studies allowing them to match patients on their caseload with active studies
Novel neutrino-floor and dark matter searches with deformed shell model calculations
Event detection rates for WIMP-nucleus interactions are calculated for
Ga, Ge, As and I (direct dark matter detectors).
The nuclear structure form factors, that are rather independent of the
underlying beyond the Standard Model particle physics scenario assumed, are
evaluated within the context of the deformed nuclear shell model (DSM) based on
Hartree-Fock nuclear states. Along with the previously published DSM results
for Ge, the neutrino-floor due to coherent elastic neutrino-nucleus
scattering (CENS), an important source of background to dark matter
searches, is extensively calculated. The impact of new contributions to
CENS due to neutrino magnetic moments and mediators at direct
dark matter detection experiments is also examined and discussed. The results
show that the neutrino-floor constitutes a crucial source of background events
for multi-ton scale detectors with sub-keV capabilities.Comment: 16 pages, 12 figures, 3 Tables; 1 figure and 1 table added;
references added; matches published versio
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