21,102 research outputs found
Decays of doubly charmed meson molecules
Several observed states close to the and
thresholds, as the X(3872) and some XYZ particles
can be described in terms of a two-meson molecule. Furthermore, doubly charmed
states are also predicted. These new states are near the and
thresholds, % Therefore, if the previous XYZ are molecules, then,
there should be doubly charmed mesons with around the
threshold.
%For this reason, it is important to evaluate observables related to them.
Because of the spin, they do not decay into . In this article we
compute decays to and radiative decays of doubly charmed meson molecules
into . and have spin-parity . Their natural decay
modes are , and and
. We evaluate the widths of these states, named here as
and , and obtain 44 MeV for the non-strangeness,
and 24 MeV for the doubly charm-strange state. Essentially, the decay modes are
and , being the and emitted by
one of the meson which forms the molecule.Comment: 31 pages, 9 figures, 20 table
Experimental assessment and retrofit of full-scale models of existing RC frames
PSD tests on two full-scale models of existing non-seismic resisting RC frame structures are
described. The testing program covered several aspects, namely assessment of seismic
performance of existing frames without and with infill panels, retrofitting of the bare frame
using Selective Retrofitting techniques, strengthening of the infill panels using shotcrete and
retrofitting of the frame using K-bracing with shear-link dissipators. The main results from
the tests are summarized and discussed and the conclusions are drawn. The tests on the bare
frame have shown how vulnerable are existing structures constructed in the 60âs and the
beneficial effects of infill panels were confirmed from the tests on the infilled frame.
Important improvements, in terms of seismic performance, were achieved by the retrofitting
of the frames. However, it was also confirmed that strengthening of the existing infill panels
in poorly detailed frames may lead to dangerous âlocalâ failures, such as the shear out of the
external columns
Evaluation of Target Date Funds
Target date funds are an emerging class of investment products, designed for retirement savings. The project considered methodologies for ranking such funds
Lending to Small Businesses: The Role of Loan Maturity in Adressing Information Problems
We investigate what determines the maturity of loans to small, informationally opaque businesses.We find that longer maturities are associated with collateral pledges, better financial condition, good credit history, and less informational opacity of the borrower.However, we do not find a positive association between stronger firm-creditor relationships (which can attenuate these information asymmetries) and longer maturities.The evidence suggests that creditors use shorter maturities to induce more frequent renegotiation of contract terms, thus enforcing closer monitoring of more informationally opaque and risky borrowers.Overall, our results are consistent with shorter loan maturities mitigating the consequences of borrower-lender informational asymmetries.small business;bank lending;loans;information
Inhomogeneous soliton ratchets under two ac forces
We extend our previous work on soliton ratchet devices [L. Morales-Molina et
al., Eur. Phys. J. B 37, 79 (2004)] to consider the joint effect of two ac
forces including non-harmonic drivings, as proposed for particle ratchets by
Savele'v et al. [Europhys. Lett. 67}, 179 (2004); Phys. Rev. E {\bf 70} 066109
(2004)]. Current reversals due to the interplay between the phases, frequencies
and amplitudes of the harmonics are obtained. An analysis of the effect of the
damping coefficient on the dynamics is presented. We show that solitons give
rise to non-trivial differences in the phenomenology reported for particle
systems that arise from their extended character. A comparison with soliton
ratchets in homogeneous systems with biharmonic forces is also presented. This
ratchet device may be an ideal candidate for Josephson junction ratchets with
intrinsic large damping
A high-performance data structure for mobile information systems
Mobile information systems can now be provided on small form-factor computers. Dictionary-based data compression extends the capabilities of systems with limited processing and memory to enable data intensive applications to be supported in such environments. The nature of judicial sentencing decisions requires that a support system provides accurate and up-to-date data and is compatible with the professional working experience of a judge. The difficulties caused by mobility and the data dependence of the decision-making process are addressed by an Internet-based architecture for collecting and distributing system data.We describe an approach to dictionary-based data compression and the structure of an information system that makes use of this technology
Inter- and intra-layer excitons in MoS/WS and MoSe/WSe heterobilayers
Accurately described excitonic properties of transition metal dichalcogenide
heterobilayers (HBLs) are crucial to comprehend the optical response and the
charge carrier dynamics of them. Excitons in multilayer systems posses inter or
intralayer character whose spectral positions depend on their binding energy
and the band alignment of the constituent single-layers. In this study, we
report the electronic structure and the absorption spectra of MoS/WS
and MoSe/WSe HBLs from first-principles calculations. We explore the
spectral positions, binding energies and the origins of inter and intralayer
excitons and compare our results with experimental observations. The absorption
spectra of the systems are obtained by solving the Bethe-Salpeter equation on
top of a GW calculation which corrects the independent particle
eigenvalues obtained from density functional theory calculations. Our
calculations reveal that the lowest energy exciton in both HBLs possesses
interlayer character which is decisive regarding their possible device
applications. Due to the spatially separated nature of the charge carriers, the
binding energy of inter-layer excitons might be expected to be considerably
smaller than that of intra-layer ones. However, according to our calculations
the binding energy of lowest energy interlayer excitons is only 20\%
lower due to the weaker screening of the Coulomb interaction between layers of
the HBLs. Therefore, it can be deduced that the spectral positions of the
interlayer excitons with respect to intralayer ones are mostly determined by
the band offset of the constituent single-layers. By comparing oscillator
strengths and thermal occupation factors, we show that in luminescence at low
temperature, the interlayer exciton peak becomes dominant, while in absorption
it is almost invisible.Comment: 17 pages, 4 figure
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