8,217 research outputs found
Vector meson-vector meson interaction in a hidden gauge unitary approach
The formalism developed recently to study vector meson--vector meson
interaction, and applied to the case of , is extended to study the
interaction of the nonet of vector mesons among themselves. The interaction
leads to poles of the scattering matrix corresponding to bound states or
resonances. We show that 11 states (either bound or resonant) get dynamically
generated in nine strangeness-isospin-spin channels. Five of them can be
identified with those reported in the PDG, i.e., the , ,
, , and . The masses of the latter three
tensor states have been used to fine-tune the free parameters of the unitary
approach, i.e., the subtraction constants in evaluating the vector meson
-vector meson loop functions in the dimensional regularization scheme. The
branching ratios of these five dynamically generated states are found to be
consistent with data. The existence of the other six states should be taken as
predictions to be tested by future experiments.Comment: typos corrected; more discussions; one of the appendix rearrange
Spin filters with Fano dots
We compute the zero bias conductance of electrons through a single ballistic
channel weakly coupled to a side quantum dot with Coulomb interaction. In
contrast to the standard setup which is designed to measure the transport
through the dot, the channel conductance reveals Coulomb blockade dips rather
then peaks due to the Fano-like backscattering. At zero temperature the Kondo
effect leads to the formation of broad valleys of small conductance
corresponding to an odd number of electrons on the dot. By applying a magnetic
field in the dot region we find two dips corresponding to a total suppression
in the conductance of spins up and down separated by an energy of the order of
the Coulomb interaction. This provides a possibility of a perfect spin filter.Comment: 5 pages, 4 figures, to be published in European Physical Journal
Environmental science applications with Rapid Integrated Mapping and analysis System (RIMS)
The Rapid Integrated Mapping and analysis System (RIMS) has been developed at the University of New Hampshire as an online instrument for multidisciplinary data visualization, analysis and manipulation with a focus on hydrological applications. Recently it was enriched with data and tools to allow more sophisticated analysis of interdisciplinary data. Three different examples of specific scientific applications with RIMS are demonstrated and discussed. Analysis of historical changes in major components of the Eurasian pan-Arctic water budget is based on historical discharge data, gridded observational meteorological fields, and remote sensing data for sea ice area. Express analysis of the extremely hot and dry summer of 2010 across European Russia is performed using a combination of near-real time and historical data to evaluate the intensity and spatial distribution of this event and its socioeconomic impacts. Integrative analysis of hydrological, water management, and population data for Central Asia over the last 30 years provides an assessment of regional water security due to changes in climate, water use and demography. The presented case studies demonstrate the capabilities of RIMS as a powerful instrument for hydrological and coupled human-natural systems research
Development of Distributed Research Center for analysis of regional climatic and environmental changes
We present an approach and first results of a collaborative project being carried out by a joint team of researchers from the Institute of Monitoring of Climatic and Ecological Systems, Russia and Earth Systems Research Center UNH, USA. Its main objective is development of a hardware and software platform prototype of a Distributed Research Center (DRC) for monitoring and projecting of regional climatic and environmental changes in the Northern extratropical areas. The DRC should provide the specialists working in climate related sciences and decision-makers with accurate and detailed climatic characteristics for the selected area and reliable and affordable tools for their in-depth statistical analysis and studies of the effects of climate change. Within the framework of the project, new approaches to cloud processing and analysis of large geospatial datasets (big geospatial data) inherent to climate change studies are developed and deployed on technical platforms of both institutions. We discuss here the state of the art in this domain, describe web based information-computational systems developed by the partners, justify the methods chosen to reach the project goal, and briefly list the results obtained so far
Quantitative assessment of reentrainment in the electrocyclone
The paper was devoted to the investigation of the reentrainment which was a parasitic effect incipient at the gas-cleaning systems – cyclones. It was demonstrated that the reentrainment arises at the speed of the aerosol from 14 to 27 m/sec. The quantitative characteristics of the reentrainment were determined.The research project has been supported by Russian Foundation for Basic Research (grant 14–08–00046а)
Exclusive charm production in pbar p collisions at s^1/2 <15 GeV
We discuss the open charm production in peripheral reactions
and , where
and stand for and
, respectively, at GeV, which corresponds to the
energy range of FAIR. Our consideration is based on the topological
decomposition of the planar quark and diquark diagrams which allows to estimate
consistently meson and baryon exchange trajectories and energy scale parameters
as well. The spin dependence is determined by the effective interaction of
lowest exchanged resonance. Unknown parameters are fixed by an independent
analysis of open strangeness production in and reactions and of SU(4) symmetry. We present the corresponding cross
sections and longitudinal double-spin asymmetries for exclusive binary
reactions with open charm mesons and baryons in the final state. The
polarization observables have a non-trivial and dependence which is
sensitive to details of the open charm production mechanism.Comment: 26 pages, 18 figure
Towards the electron EDM search: Theoretical study of HfF+
We report first ab initio relativistic correlation calculations of potential
curves for ten low-lying electronic states, effective electric field on the
electron and hyperfine constants for the ^3\Delta_1 state of cation of a heavy
transition metal fluoride, HfF^+, that is suggested to be used as the working
state in experiments to search for the electric dipole moment of the electron.
It is shown that HfF^+ has deeply bound ^1\Sigma^+ ground state, its
dissociation energy is D_e=6.4 eV. The ^3\Delta_1 state is obtained to be the
relatively long-lived first excited state lying about 0.2 eV higher. The
calculated effective electric field E_eff=W_d|\Omega| acting on an electron in
this state is 5.84*10^{24}Hz/(e*cm)Comment: 4 page
High-resolution radio imaging of two luminous quasars beyond redshift 4.5
Context. Radio-loud active galactic nuclei in the early Universe are rare.
The quasars J0906+6930 at redshift z=5.47 and J2102+6015 at z=4.57 stand out
from the known sample with their compact emission on milliarcsecond (mas)
angular scale with high (0.1-Jy level) flux densities measured at GHz radio
frequencies. This makes them ideal targets for very long baseline
interferometry (VLBI) observations. Aims. By means of VLBI imaging we can
reveal the inner radio structure of quasars and model their brightness
distribution to better understand the geometry of the jet and the physics of
the sources. Methods. We present sensitive high-resolution VLBI images of
J0906+6930 and J2102+6015 at two observing frequencies, 2.3 and 8.6 GHz. The
data were taken in an astrometric observing programme involving a global
five-element radio telescope array. We combined the data from five different
epochs from 2017 February to August. Results. For one of the highest redshift
blazars known, J0906+6930, we present the first-ever VLBI image obtained at a
frequency below 8 GHz. Based on our images at 2.3 and 8.6 GHz, we confirm that
this source has a sharply bent helical inner jet structure within ~3 mas from
the core. The quasar J2102+6015 shows an elongated radio structure in the
east-west direction within the innermost ~2 mas that can be described with a
symmetric three-component brightness distribution model at 8.6 GHz. Because of
their non-pointlike mas-scale structure, these sources are not ideal as
astrometric reference objects. Our results demonstrate that VLBI observing
programmes conducted primarily with astrometric or geodetic goals can be
utilized for astrophysical purposes as well.Comment: 8 pages, 3 figures, accepted for publication in Astronomy &
Astrophysic
A new interpretation for the and the prediction of novel exotic charmed mesons
In this manuscript we study the vector - vector interaction within the hidden
gauge formalism in a coupled channel unitary approach. In the sector
we get a pole in the T-matrix around MeV that we identify
with the , coupling strongly to the
(()) channels. In addition we obtain resonances in
other exotic sectors which have not been studied before such as ,
and . This 'flavor-exotic' states are interpreted as
, and molecular states but have not been
observed yet. In total we obtain nine states with different spin, isospin,
charm and strangeness of non and character, which have been
reported before
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