3,772 research outputs found
Search for the signal of monotop production at the early LHC
We investigate the potential of the early LHC to discover the signal of
monotops, which can be decay products of some resonances in models such as
R-parity violating SUSY or SU(5), etc. We show how to constrain the parameter
space of the models by the present data of boson hadronic decay branching
ratio, mixing and dijet productions at the LHC. Then, we study
the various cuts imposed on the events, reconstructed from the hadronic final
states, to suppress backgrounds and increase the significance in detail. And we
find that in the hadronic mode the information from the missing transverse
energy and reconstructed resonance mass distributions can be used to specify
the masses of the resonance and the missing particle. Finally, we study the
sensitivities to the parameters at the LHC with =7 TeV and an
integrated luminosity of in detail. Our results show that the
early LHC may detect this signal at 5 level for some regions of the
parameter space allowed by the current data.Comment: 25 pages, 18 figures, 3 tables, version published in Phys.Rev.
Differential measurement of atmospheric refraction with a telescope with double fields of view
For the sake of complete theoretical research of atmospheric refraction, the
atmospheric refraction under the condition of lower angles of elevation is
still worthy to be analyzed and explored. In some engineering applications, the
objects with larger zenith distance must be observed sometimes. Carrying out
observational research of the atmospheric refraction at lower angles of
elevation has an important significance. It has been considered difficult to
measure the atmospheric refraction at lower angles of elevation. A new idea for
determining atmospheric refraction by utilizing differential measurement with
double fields of view is proposed. Taking the observational principle of
HIPPARCOS satellite as a reference, a schematic prototype with double fields of
view was developed. In August of 2013, experimental observations were carried
out and the atmospheric refractions at lower angles of elevation can be
obtained by the schematic prototype. The measured value of the atmospheric
refraction at the zenith distance of 78.8 degree is , and the
feasibility of differential measurement of atmospheric refraction with double
fields of view was justified. The limitations of the schematic prototype such
as inadequate ability of gathering light, lack of accurate meteorological data
recording and lower automatic level of observation and data processing were
also pointed out, which need to be improved in subsequent work.Comment: 10 pages, 6 figure
Investigating the topological structure of quenched lattice QCD with overlap fermions by using multi-probing approximation
The topological charge density and topological susceptibility are determined
by multi-probing approximation using overlap fermions in quenched SU(3) gauge
theory. Then we investigate the topological structure of the quenched QCD
vacuum, and compare it with results from the all-scale topological density, the
results are consistent. Random permuted topological charge density is used to
check whether these structures represent underlying ordered properties.
Pseudoscalar glueball mass is extracted from the two-point correlation function
of the topological charge density. We study ensembles of different lattice
spacing with the same lattice volume , the results are
compatible with the results of all-scale topological charge density, and the
topological structures revealed by multi-probing are much closer to all-scale
topological charge density than that by eigenmode expansion.Comment: 12 pages,34 figure
Renormalization group improved pQCD prediction for leptonic decay
The complete next-to-next-to-next-to-leading order short-distance and
bound-state QCD corrections to leptonic decay rate
has been finished by Beneke {\it et al.}
\cite{Beneke:2014qea}. Based on those improvements, we present a
renormalization group (RG) improved pQCD prediction for by applying the principle of maximum conformality (PMC). The PMC
is based on RG-invariance and is designed to solve the pQCD renormalization
scheme and scale ambiguities. After applying the PMC, all known-type of
-terms at all orders, which are controlled by the RG-equation, are
resummed to determine optimal renormalization scale for its strong running
coupling at each order. We then achieve a more convergent pQCD series, a
scheme- independent and more accurate pQCD prediction for
leptonic decay, i.e. keV, where the uncertainty is the squared average of
the mentioned pQCD errors. This RG-improved pQCD prediction agrees with the
experimental measurement within errors.Comment: 11 pages, 4 figures. Numerical results and discussions improved,
references updated, to be published in JHE
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