6,371 research outputs found
Ground states and excited states of hypernuclei in Relativistic Mean Field approach
Hypernuclei have been studied within the framework of Relativistic Mean Field
theory. The force FSU Gold has been extended to include hyperons. The effective
hyperon-nucleon and nucleon-nucleon interactions have been obtained by fitting
experimental energies in a number of hypernuclei over a wide range of mass.
Calculations successfully describe various features including hyperon
separation energy and single particle spectra of single-\Lambda hypernuclei
throughout the periodic table. We also extend this formalism to double-\Lambda
hypernuclei.Comment: 16 pages,3 figure
Interpreting time-integrated polarization data of gamma-ray burst prompt emission
Aims. With the accumulation of polarization data in the gamma-ray burst (GRB)
prompt phase, polarization models can be tested. Methods. We predicted the
time-integrated polarizations of 37 GRBs with polarization observation. We used
their observed spectral parameters to do this. In the model, the emission
mechanism is synchrotron radiation, and the magnetic field configuration in the
emission region was assumed to be large-scale ordered. Therefore, the predicted
polarization degrees (PDs) are upper limits. Results. For most GRBs detected by
the Gamma-ray Burst Polarimeter (GAP), POLAR, and AstroSat, the predicted PD
can match the corresponding observed PD. Hence the synchrotron-emission model
in a large-scale ordered magnetic field can interpret both the moderately low
PDs () detected by POLAR and relatively high PDs ()
observed by GAP and AstroSat well. Therefore, the magnetic fields in these GRB
prompt phases or at least during the peak times are dominated by the ordered
component. However, the predicted PDs of GRB 110721A observed by GAP and GRB
180427A observed by AstroSat are both lower than the observed values. Because
the synchrotron emission in an ordered magnetic field predicts the upper-limit
of the PD for the synchrotron-emission models, PD observations of the two
bursts challenge the synchrotron-emission model. Then we predict the PDs of the
High-energy Polarimetry Detector (HPD) and Low-energy Polarimetry Detector
(LPD) on board the upcoming POLAR-2. In the synchrotron-emission models, the
concentrated PD values of the GRBs detected by HPD will be higher than the LPD,
which might be different from the predictions of the dissipative photosphere
model. Therefore, more accurate multiband polarization observations are highly
desired to test models of the GRB prompt phase.Comment: 6 pages, 5 figures, with updated AstroSat data, accepted by A
Electromagnetic manipulation for anti-Zeno effect in an engineered quantum tunneling process
We investigate the quantum Zeno and anti-Zeno effects for the irreversible
quantum tunneling from a quantum dot to a ring array of quantum dots. By
modeling the total system with the Anderson-Fano-Lee model, it is found that
the transition from the quantum Zeno effect to quantum anti-Zeno effect can
happen as the magnetic flux and the gate voltage were adjusted.Comment: 6 pages, 5 figure
Seasonal and diurnal variations of atmospheric mercury across the US determined from AMNet monitoring data
Speciated atmospheric mercury observations collected over the period from 2008 to 2010 at the Environmental Protection Agency and National Atmospheric Deposition Program Atmospheric Mercury Network sites (AMNet) were analyzed for its spatial, seasonal, and diurnal characteristics across the US. Median values of gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM) and particulate bound mercury (PBM) at 11 different AMNet sites ranged from 148–226 ppqv (1.32–2.02 ng m<sup>−3</sup>), 0.05–1.4 ppqv (0.47–12.4 pg m<sup>−3</sup>) and 0.18–1.5 ppqv (1.61–13.7 pg m<sup>−3</sup>), respectively. Common characteristics of these sites were the similar median levels of GEM as well as its seasonality, with the highest mixing ratios occurring in winter and spring and the lowest in fall. However, discernible differences in monthly average GEM were as large as 30 ppqv, which may be caused by sporadic influence from local emission sources. The largest diurnal variation amplitude of GEM occurred in the summer. Seven rural sites displayed similar GEM summer diurnal patterns, in that the lowest levels appeared in the early morning, and then the GEM mixing ratio increased after sunrise and reached its maxima at noon or in the early afternoon. Unlike GEM, GOM exhibited higher mixing ratios in spring and summer. The largest diurnal variation amplitude of GOM occurred in spring for most AMNet sites. The GOM diurnal minima appeared before sunrise and maxima appeared in the afternoon. The increased GOM mixing ratio in the afternoon indicated a photochemically driven oxidation of GEM resulting in GOM formation. PBM exhibited diurnal fluctuations in summertime. The summertime PBM diurnal pattern displayed daily maxima in the early afternoon and lower mixing ratios at night, implying photochemical production of PBM in summer
Approximation of conformal mappings by circle patterns
A circle pattern is a configuration of circles in the plane whose
combinatorics is given by a planar graph G such that to each vertex of G
corresponds a circle. If two vertices are connected by an edge in G, the
corresponding circles intersect with an intersection angle in .
Two sequences of circle patterns are employed to approximate a given
conformal map and its first derivative. For the domain of we use
embedded circle patterns where all circles have the same radius decreasing to 0
and which have uniformly bounded intersection angles. The image circle patterns
have the same combinatorics and intersection angles and are determined from
boundary conditions (radii or angles) according to the values of (
or ). For quasicrystallic circle patterns the convergence result is
strengthened to -convergence on compact subsets.Comment: 36 pages, 7 figure
Constraints on the phase and new physics from Decays
Recent results from CLEO on indicate that the phase may
be substantially different from that obtained from other fit to the KM matrix
elements in the Standard Model. We show that extracted using is sensitive to new physics occurring at loop level. It provides
a powerful method to probe new physics in electroweak penguin interactions.
Using effects due to anomalous gauge couplings as an example, we show that
within the allowed ranges for these couplings information about
obtained from can be very different from the Standard
Model prediction.Comment: Revised version with analysis done using new data from CLEO. RevTex,
11 Pages with two figure
Probing the lightest new gauge boson in the littlest Higgs model via the processes at the ILC
The neutral gauge boson with the mass of hundreds GeV, is the lightest
particle predicted by the littlest Higgs(LH) model, and such particle should be
the first signal of the LH model at the planed ILC if it exists indeed. In this
paper, we study some processes of the production associated with the
fermion pair at the ILC, i.e., . The studies
show that the most promising processes to detect among are , and they can
produce the sufficient signals in most parameter space preferred by the
electroweak precision data at the ILC. On the other hand, the signal produced
via the certain decay modes is typical and such signal can be easily
identified from the SM background. Therefore, , the lightest gauge boson
in the LH model would be detectable at the photon collider realized at the ILC.Comment: 12 pages, 4 figure
You can't see what you can't see: Experimental evidence for how much relevant information may be missed due to Google's Web search personalisation
The influence of Web search personalisation on professional knowledge work is
an understudied area. Here we investigate how public sector officials
self-assess their dependency on the Google Web search engine, whether they are
aware of the potential impact of algorithmic biases on their ability to
retrieve all relevant information, and how much relevant information may
actually be missed due to Web search personalisation. We find that the majority
of participants in our experimental study are neither aware that there is a
potential problem nor do they have a strategy to mitigate the risk of missing
relevant information when performing online searches. Most significantly, we
provide empirical evidence that up to 20% of relevant information may be missed
due to Web search personalisation. This work has significant implications for
Web research by public sector professionals, who should be provided with
training about the potential algorithmic biases that may affect their judgments
and decision making, as well as clear guidelines how to minimise the risk of
missing relevant information.Comment: paper submitted to the 11th Intl. Conf. on Social Informatics;
revision corrects error in interpretation of parameter Psi/p in RBO resulting
from discrepancy between the documentation of the implementation in R
(https://rdrr.io/bioc/gespeR/man/rbo.html) and the original definition
(https://dl.acm.org/citation.cfm?id=1852106) as per 20/05/201
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