7,629 research outputs found
Research Program towards Observation of Neutrino-Nucleus Coherent Scattering
The article describes the research program pursued by the TEXONO
Collaboration towards an experiment to observe coherent scattering between
neutrinos and the nucleus at the power reactor. The motivations of studying
this process are surveyed. In particular, a threshold of 100-200 eV has been
achieved with an ultra-low-energy germanium detector prototype. This detection
capability at low energy can also be adapted to conduct searches of Cold Dark
Matter in the low-mass region as well as to enhance the sensitivities in the
study of neutrino magnetic moments.Comment: 5 pages, 8 figures ; Proceedings of TAUP-2005 Workshop, Spain, 2005.
Updated on 2006/9/15 for Proceedings of Neutrino-2006 Conference, Santa Fe,
200
Topological quantum phase transition in an extended Kitaev spin model
We study the quantum phase transition between Abelian and non-Abelian phases
in an extended Kitaev spin model on the honeycomb lattice, where the periodic
boundary condition is applied by placing the lattice on a torus. Our analytical
results show that this spin model exhibits a continuous quantum phase
transition. Also, we reveal the relationship between bipartite entanglement and
the ground-state energy. Our approach directly shows that both the entanglement
and the ground-state energy can be used to characterize the topological quantum
phase transition in the extended Kitaev spin model.Comment: 9 Pages, 4 figure
Coherency in Neutrino-Nucleus Elastic Scattering
Neutrino-nucleus elastic scattering provides a unique laboratory to study the
quantum mechanical coherency effects in electroweak interactions, towards which
several experimental programs are being actively pursued. We report results of
our quantitative studies on the transitions towards decoherency. A parameter
() is identified to describe the degree of coherency, and its
variations with incoming neutrino energy, detector threshold and target nucleus
are studied. The ranges of which can be probed with realistic neutrino
experiments are derived, indicating complementarity between projects with
different sources and targets. Uncertainties in nuclear physics and in
would constrain sensitivities in probing physics beyond the standard model. The
maximum neutrino energies corresponding to >0.95 are derived.Comment: 5 pages, 4 figures, 3 tables. V2 -- Published Versio
Electron Dispersion and Parallel Electron Beam Observed Near the Separatrix
The separatrix region is the region between the separatrix and the reconnection jet. Due to the EĂB drift and velocity filter effect in which highâenergy particles with high parallel speed can be seen prior to lowâenergy particles along the field line, electrons are separated from ions. The electron dynamics in this region is of interest; however it has not been studied in detail, because of the insufficient resolution of plasma data. We present a slow separatrix crossing event observed by Magnetospheric Multiscale (MMS) satellite constellation on 1 January 2016, from the magnetosheath side with highâresolution burst mode data. The electron edge and ion edge are clearly distinguished in the separatrix region. Two types of electron dispersion, one with a short duration (~0.3 s) and the other with a longer duration (~13 s) were detected between the electron and ion edges. The rapid dispersion (with small time scale) is mainly in the parallel direction, which might originate from a thin layer with nonâfrozenâin electrons close to the separatrix. The gradual (long time scale) dispersion is seen from parallel to perpendicular directions, which comes from the EĂB drift of a curved Dâshape distribution of electrons. The width of the electron diffusion region on the magnetosheath side is estimated based on MMS observation. The observation also reveals an unexpected parallel electron beam outside of the electron edge. Waveâparticle interaction or parallel potential in the inflow region may be responsible for the generation of this electron population
Global axisymmetric stability analysis for a composite system of two gravitationally coupled scale-free discs
In a composite system of gravitationally coupled stellar and gaseous discs,
we perform linear stability analysis for axisymmetric coplanar perturbations
using the two-fluid formalism. The background stellar and gaseous discs are
taken to be scale-free with all physical variables varying as powers of
cylindrical radius with compatible exponents. The unstable modes set in as
neutral modes or stationary perturbation configurations with angular frequency
.Comment: 7 pages using AAS styl
Constraints on Non-Commutative Physics Scale with Neutrino-Electron Scattering
Neutrino-electron scatterings () are purely leptonic processes with
robust Standard Model (SM) predictions. Their measurements can therefore
provide constraints to physics beyond SM. Non-commutative (NC) field theories
modify space-time commutation relations, and allow neutrino electromagnetic
couplings at the tree level. Their contribution to neutrino-electron scattering
cross-section was derived. Constraints were placed on the NC scale parameter
from experiments with reactor and accelerator
neutrinos. The most stringent limit of at 95%
confidence level improves over the direct bounds from collider experiments.Comment: 6 pages, 2 figures, 2 tables, V2: minor revisions to match published
versio
EP-1625: A dosimetric analysis of semi-automated knowledge-based VMAT planning for rectal cancer patients
Energy-Efficient URLLC Service Provision via a Near-Space Information Network
The integration of a near-space information network (NSIN) with the
reconfigurable intelligent surface (RIS) is envisioned to significantly enhance
the communication performance of future wireless communication systems by
proactively altering wireless channels. This paper investigates the problem of
deploying a RIS-integrated NSIN to provide energy-efficient, ultra-reliable and
low-latency communications (URLLC) services. We mathematically formulate this
problem as a resource optimization problem, aiming to maximize the effective
throughput and minimize the system power consumption, subject to URLLC and
physical resource constraints. The formulated problem is challenging in terms
of accurate channel estimation, RIS phase alignment, theoretical analysis, and
effective solution. We propose a joint resource allocation algorithm to handle
these challenges. In this algorithm, we develop an accurate channel estimation
approach by exploring message passing and optimize phase shifts of RIS
reflecting elements to further increase the channel gain. Besides, we derive an
analysis-friend expression of decoding error probability and decompose the
problem into two-layered optimization problems by analyzing the monotonicity,
which makes the formulated problem analytically tractable. Extensive
simulations have been conducted to verify the performance of the proposed
algorithm. Simulation results show that the proposed algorithm can achieve
outstanding channel estimation performance and is more energy-efficient than
diverse benchmark algorithms
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