42,098 research outputs found
New Physics Searches with Higgs-photon associated production at the Higgs Factory
The Higgs factory is designed for precise measurement of Higgs characters and
search for new physics. In this paper we propose that
process could be a useful channel for new physics, which is normally expressed
model independently by effective field theory. We calculate the cross section
in both the Standard Model and effective field theory approach, and find that
the new physics effects of have only two degrees of freedom, much
fewer than the Higgsstrahlung process. This point could be used to reduce the
degeneracies of Wilson coefficients. We also calculated for the first time the
2 bounds of at the Higgs factory, and prove that
is more sensitive to some dimension-6 operators than the current experimental
data. In the optimistic scenario new physics effects may be observed at the
CEPC or FCC-ee after the first couple of years of their run.Comment: 5 pages, 3 figures, submitted to Chinese Physics
Minimax Estimation of Large Precision Matrices with Bandable Cholesky Factor
Last decade witnesses significant methodological and theoretical advances in
estimating large precision matrices. In particular, there are scientific
applications such as longitudinal data, meteorology and spectroscopy in which
the ordering of the variables can be interpreted through a bandable structure
on the Cholesky factor of the precision matrix. However, the minimax theory has
still been largely unknown, as opposed to the well established minimax results
over the corresponding bandable covariance matrices. In this paper, we focus on
two commonly used types of parameter spaces, and develop the optimal rates of
convergence under both the operator norm and the Frobenius norm. A striking
phenomenon is found: two types of parameter spaces are fundamentally different
under the operator norm but enjoy the same rate optimality under the Frobenius
norm, which is in sharp contrast to the equivalence of corresponding two types
of bandable covariance matrices under both norms. This fundamental difference
is established by carefully constructing the corresponding minimax lower
bounds. Two new estimation procedures are developed: for the operator norm, our
optimal procedure is based on a novel local cropping estimator targeting on all
principle submatrices of the precision matrix while for the Frobenius norm, our
optimal procedure relies on a delicate regression-based thresholding rule.
Lepski's method is considered to achieve optimal adaptation. We further
establish rate optimality in the nonparanormal model. Numerical studies are
carried out to confirm our theoretical findings
SU(2) x SU(2) x U(1) Interpretation on the 750 GeV Diphoton Excess
We propose that the SU(2) x SU(2) x U(1) (aka G221) models could provide us a
750 GeV scalar resonance that may account for the diphoton excess observed at
the LHC while satisfying present collider constraints. The neutral component of
the scalar multiplet can be identified as the 750 GeV scalar. In the
lepto-phobic and fermio-phobic G221 models the new charged gauge boson W' could
be light, and we find that the diphoton decay width could be dominated by the
loop contribution from the . To initiate gluon fusion production, it is
necessary to extend the G221 symmetry to the Pati-Salam and SO(10) symmetry. We
investigate the possibilities that the light colored scalars or vectorlike
fermions survive in the SO(10) theory and provide large gluon fusion rate for
the diphoton signature. It is possible to test the G221 interpretation by
direct searches of W' using the multi-gauge boson production channel at the Run
2 LHC.Comment: 26 pages, 3 figures, 2 table
Space-Distribution PDEs for Path Independent Additive Functionals of McKean-Vlasov SDEs
Let P2(Rd) be the space of probability measures on Rd with finite second
moment. The path independence of additive functionals of McKean-Vlasov SDEs is
characterized by PDEs on the product space Rd*P2(Rd) equipped with the usual
derivative in space variable and Lions derivative in distribution. These PDEs
are solved by using probabilis- tic arguments developed from [2]. In
particular, the path independence of the Girsanov transformation killing the
drift term is identified with a nonlinear PDE on Rd*P2(Rd), which includes
corresponding results derived earlier for the classical SDEs as special
situations.Comment: 17 PAGE
Model-independent Probe of anomalous heavy neutral Higgs bosons at the LHC
We first formulate, in the framework of effective Lagrangian, the general
form of the effective interactions of the lightest Higgs boson h and a heavier
neutral Higgs boson H in a multi-Higgs system taking account of Higgs mixing
effect. We regard h as the discovered Higgs boson which has been shown to be
consistent with the standard model (SM) Higgs boson. The obtained effective
interactions contain extra parameters reflecting the Higgs mixing effect. Next,
We study the constraints on the anomalous coupling constants of H from both the
requirement of the unitarity of the S matrix and the exclusion bounds on the SM
Higgs boson obtained from the experimental data at the 7--8 TeV LHC. From this
we obtain the available range of the anomalous coupling constants of H, with
which H is not excluded by the yet known theoretical and experimental
constraints. We then study the signatures of H at the 14 TeV LHC. In this
paper, we suggest taking weak-boson scattering and pp to VH* to VVV as
sensitive processes for probing H model independently at the 14 TeV LHC. We
take several examples with the anomalous HVV coupling constants in the
available ranges to do the numerical study. a full tree-level calculation at
the hadron level is given with signals and backgrounds carefully calculated. We
impose a series of proper kinematic cuts to effectively suppress the
backgrounds. It is shown that, in both the VV scattering and the pp to VH* to
VVV processes, H boson can be discovered from the invariant mass distributions
of the final state particles with reasonable integrated luminosity. Especially,
in the pp to VH* to VVV process, the invariant mass distribution of the final
state jets can show a clear resonance peak of H. Finally, we propose several
physical observables from which the values of the anomalous coupling constants
f_W and f_{WW} can be measured experimentally.Comment: revtex4, 25pages, with 21 eps files for 21 figures. Tp appear in
Phys. Rev. D 90 (2014
Further Investigation on Model-Independent Probe of Heavy Neutral Higgs Bosons at the LHC Run 2
In our previous paper, we provided general effective Higgs interactions for
the lightest Higgs boson (SM-like) and a heavier neutral Higgs boson
based on the effective Lagrangian formulation up to the dim-6 interactions, and
then proposed two sensitive processes for probing . We showed in several
examples that the resonance peak of and its dim-6 effective coupling
constants (ECC) can be detected at the LHC Run 2 with reasonable integrated
luminosity. In this paper, we further perform a more thorough study of the most
sensitive process, , on the information about the
relations between the statistical significance
and the corresponding ranges of the Higgs ECC for an integrated luminosity of
100 fb. These results have two useful applications in the LHC Run 2: (A)
realizing the experimental determination of the ECC in the dim-6 interactions
if is found and, (B) obtaining the theoretical exclusion bounds if is
not found. Some alternative processes sensitive for certain ranges of the ECC
are also analyzed.Comment: 10 pages, 12 figures, to be submitted to Chinese Physics
Fermions tunnelling with quantum gravity correction
Quantum gravity correction is truly important to study tunnelling process of
black hole. Base on the generalized uncertainty principle, we investigate the
influence of quantum gravity and the result tell us that the quantum gravity
correction accelerates the evaporation of black hole. Using corrected Dirac
equation in curved spacetime and Hamilton-Jacobi method, we address the
tunnelling of fermions in a 4-dimensional Schwarzschild spacetime.
After solving the equation of motion of the spin 1/2 field, we obtain the
corrected Hawking temperature. It turns out that the correction depends not
only on the mass of black hole but aslo on the mass of emitted fermions. In our
calculation, the quantum gravity correction accelerates the increasing of
Hawking temperature during the radiation explicitly. This correction leads to
the increasing of the evaporation of black hole.Comment: 5page
3D Contouring for Breast Tumor in Sonography
Malignant and benign breast tumors present differently in their shape and
size on sonography. Morphological information provided by tumor contours are
important in clinical diagnosis. However, ultrasound images contain noises and
tissue texture; clinical diagnosis thus highly depends on the experience of
physicians. The manual way to sketch three-dimensional (3D) contours of breast
tumor is a time-consuming and complicate task. If automatic contouring could
provide a precise breast tumor contour that might assist physicians in making
an accurate diagnosis. This study presents an efficient method for
automatically contouring breast tumors in 3D sonography. The proposed method
utilizes an efficient segmentation procedure, i.e. level-set method (LSM), to
automatic detect contours of breast tumors. This study evaluates 20 cases
comprising ten benign and ten malignant tumors. The results of computer
simulation reveal that the proposed 3D segmentation method provides robust
contouring for breast tumor on ultrasound images. This approach consistently
obtains contours similar to those obtained by manual contouring of the breast
tumor and can save much of the time required to sketch precise contours.Comment: 18 pages, 1 table and 5 figure
Distance and distance signless Laplacian spread of connected graphs
For a connected graph on vertices, recall that the distance signless
Laplacian matrix of is defined to be ,
where is the distance matrix, and is the row sum of corresponding to vertex
. Denote by the
largest eigenvalue and the least eigenvalue of , respectively.
And denote by , the largest
eigenvalue and the least eigenvalue of , respectively. The
distance spread of a graph is defined as
, and
the distance signless Laplacian spread of a graph is defined as
. In this
paper, we point out an error in the result of Theorem 2.4 in "Distance spectral
spread of a graph" [G.L. Yu, et al, Discrete Applied Mathematics. 160 (2012)
2474--2478] and rectify it. As well, we obtain some lower bounds on ddistance
signless Laplacian spread of a graph
Noise and chaotic disturbance on self-similar set
The effect of noise on self-similar set is studied. The iteratie procedure
used to generate the self-similar set is moidified by adding a stochastic
variable to the diameter of generating sets at each iteration. The noise may
causes the generating set to collapse to a point. Distribution functions are
found describing the probability that any generating set collapse. The effect
of chaotic disturbance on the iteration of self-similar set is studied. It is
shown that the iterative procedure which describes the self-similar set is
truncated under the influence of disturbance generated by the tent map.
Conditions which lead to truncation of any chaotic map are also obtained.Comment: 9 pages with no figure
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