5,622 research outputs found
Holographic QCD with Topologically Charged Domain-Wall/Membranes
We study the thermodynamical phase structures of holographic QCD with
nontrivial topologically charged domain-wall/membranes which are originally
related to the multiple -vacua in the large limit. We realize the
topologically charged membranes as the holographic D6-brane fluxes in the
Sakai-Sugimoto model. The D6-brane fluxes couple to the probe D8-anti-D8 via
Chern-Simon term, and act as the source for the baryonic current density of
QCD. We find rich phase structures of the dual meson system by varying
asymptotic separation of D8 and anti-D8. Especially, there can be a
thermodynamically favored and stable phase of finite baryonic current density.
This provides the supporting evidence for the discovery of the topologically
charged membranes found in the lattice QCD calculations. We also find a
crossover phase with the limiting baryonic current density and temperature
which suggest a Hagedorn-like phase transition of meson dissociation.Comment: 23 pages, 19 figures;v2 typos corrected;v3 text improve
Charged BTZ-like black hole solutions and the diffusivity-butterfly velocity relation
We show that there exists a class of charged BTZ-like black hole solutions in
Lifshitz spacetime with a hyperscaling violating factor. The charged BTZ is
characterized by a charge-dependent logarithmic term in the metric function. As
concrete examples, we give five such charged BTZ-like black hole solutions and
the standard charged BTZ metric can be regarded as a special instance of them.
In order to check the recent proposed universal relations between diffusivity
and the butterfly velocity, we first compute the diffusion constants of the
standard charged BTZ black holes and then extend our calculation to arbitrary
dimension , exponents and . Remarkably, the case and
is a very special in that the charge diffusion is a constant and
the energy diffusion might be ill-defined, but diverges. We
also compute the diffusion constants for the case that the DC conductivity is
finite but in the absence of momentum relaxation.Comment: 30 pages, 2 figure
Explaining the DAMPE data with scalar dark matter and gauged interaction
Inspired by the peak structure observed by recent DAMPE experiment in
cosmic-ray spectrum, we consider a scalar dark matter (DM) model with
gauged symmetry, which is the most economical anomaly-free
theory to potentially explain the peak by DM annihilation in nearby subhalo. We
utilize the process , where , , denote the scalar DM,
the new gauge boson and , respectively, to generate the
spectrum. By fitting the predicted spectrum to the experimental data,
we obtain the favored DM mass range and at
Confidence Level (C.L.). Furthermore, we determine the parameter space
of the model which can explain the peak and meanwhile satisfy the constraints
from DM relic abundance, DM direct detection and the collider bounds. We
conclude that the model we consider can account for the peak, although there
exists a tension with the constraints from the LEP-II bound on
arising from the cross section measurement of .Comment: 15 pages, 4 figure
Neutral Higgs boson contributions to CP asymmetry of in MSSM
We have studied the neutral Higgs boson (NHB) contributions to the pure
penguin process in MSSM with middle and large (say,
8). We show that the order hadronic matrix elements of NHB
induced operators can make sizable effects on both the branch ratio and time
dependent CP asymmetry . Under the all relevant experimental
constraints, the Higgs mediated contributions to alone can provide
a significant deviation from SM and, in particular, lead to a negative which is reported by BaBar and Belle.Comment: 7 pages and 6 figure
CP asymmetries in and in MSSM
We study the and B\to \ep K_S decays in MSSM by calculating
hadronic matrix elements of operators with QCD factorization approach and
including neutral Higgs boson (NHB) contributions. We calculate the Wilson
coefficients of operators including the new operators which are induced by NHB
penguins at LO using the MIA with double insertions. We calculate the
order hadronic matrix elements of the new operators for and . It is shown that the recent experimental
results on the time-dependent CP asymmetries in and B\to \ep
K_S, is negative and is positive, which can
not be explained in SM, can be explained in MSSM if there are flavor
non-diagonal squark mass matrix elements of 2nd and 3rd generations whose size
satisfies all relevant constraints from known experiments (, etc.). In
particular, we find that one can explain the experimental results with a flavor
non-diagonal mass insertion of any chirality when corrections of
hadronic matrix elements of operators are included, in contrast with the claim
in the literature. At the same time, the branching ratios for the two decays
can also be in agreement with experimental measurements.Comment: 21 pages, 23 figures. Some changes have been made, which include
comments on contributions to and from RR and
RL insertion and some typing error
- …