2,120 research outputs found
Study on the radiative decays of via intermediate meson loops model
Recently, the BESIII Collaboration reported two new decay processes
and . Inspired by this
measurement, we propose to study the radiative decays of via intermediate
charmed meson loops in an effective Lagrangian approach. With the acceptable
cutoff parameter range, the calculated branching ratios of and are orders of and , respectively. The ratio can reproduce the experimental
measurements with the commonly acceptable range. This ratio provide us
some information on the mixing, which may be helpful for us
to test SU(3)-flavor symmetries in QCD.Comment: 11 pages, 5 figures, accepted for publication in EPJ
Kinetic study for hopping conduction through DNA molecules
Recent experiments indicated that disorder effect in DNA may lead to a
transition of the charge transport mechanism from band resonant tunnelling to
thermal activated hopping. In this letter, based on Mott's variable-range
hopping theory we present a kinetic study for the charge transport properties
of DNA molecules. Beyond the conventional argument in large-scale systems, our
numerical study for finite-size DNA molecules reveals a number of unique
features for (i) the I-V characteristics, (ii) the temperature and length
dependence, and (iii) the transition from conducting to insulating behaviors.Comment: 3 pages, 3 figures, submitted to Appl. Phys. Let
Heterogeneity in structurally arrested hard spheres
When cooled or compressed sufficiently rapidly, a liquid vitrifies into a glassy amorphous state. Vitrification in a dense liquid is associated with jamming of the particles. For hard spheres, the density and degree of order in the final structure depend on the compression rate: simple intuition suggests, and previous computer simulation demonstrates, that slower compression results in states that are both denser and more ordered. In this work, we use the Lubachevsky-Stillinger algorithm to generate a sequence of structurally arrested hard-sphere states by varying the compression rate. We find that while the degree of order, as measured by both bond-orientation and translation order parameters, increases monotonically with decreasing compression rate, the density of the arrested state first increases, then decreases, then increases again, as the compression rate decreases, showing a minimum at an intermediate compression rate. Examination of the distribution of the local order parameters and the distribution of the root-mean-square fluctuation of the particle positions, as well as direct visual inspection of the arrested structures, reveal that they are structurally heterogeneous, consisting of disordered, amorphous regions and locally ordered crystal-like domains. In particular, the low-density arrested states correspond with many interconnected small crystal clusters that form a polycrystalline network interspersed in an amorphous background, suggesting that jamming by the domains may be an important mechanism for these states
Cross-correlations mediated by Majorana bound states
We consider the correlated parallel transport through two quantum dots which
are tunnel-coupled to the ends of a semiconductor nanowire where the Majorana
bound states (MBSs) may emerge under proper conditions. In terms of the
cross-correlation of currents, we reveal unusual behaviors originated from the
nonlocal MBSs, including such as the distinct symmetry and antisymmetry of the
spectral density in response to the dot-level modulations, and the vanished
cross correlation occurred when any of the dot-levels is in resonance with the
Majorana zero mode
at CEPC: ISR effect with MadGraph
The Circular Electron Positron Collider (CEPC) is a future Higgs factory
proposed by the Chinese high energy physics community. It will operate at a
center-of-mass energy of 240-250 GeV. The CEPC will accumulate an integrated
luminosity of 5 ab in ten years' operation. With GEANT4-based full
simulation samples for CEPC, Higgs boson decaying into electron pair is studied
at the CEPC. The upper limit of could reach
0.024\% at 95\% confidence level. The signal process is generated by MadGraph,
with Initial State Radiation (ISR) implemented, as a first step to adjust
MadGraph for a electron positron Collider.Comment: Accepted version by J.P.
Solving Einstein equations using deep learning
Einstein field equations are notoriously challenging to solve due to their
complex mathematical form, with few analytical solutions available in the
absence of highly symmetric systems or ideal matter distribution. However,
accurate solutions are crucial, particularly in systems with strong
gravitational field such as black holes or neutron stars. In this work, we use
neural networks and auto differentiation to solve the Einstein field equations
numerically inspired by the idea of physics-informed neural networks (PINNs).
By utilizing these techniques, we successfully obtain the Schwarzschild metric
and the charged Schwarzschild metric given the energy-momentum tensor of
matter. This innovative method could open up a different way for solving
space-time coupled Einstein field equations and become an integral part of
numerical relativity.Comment: 18 pages, 4 figure
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