47,162 research outputs found
Doubly-charged scalar in four-body decays of neutral flavored mesons
In this paper, we study the four-body decay processes of neutral flavored
mesons, including , , , and . These
processes, which induced by a hypothetical doubly-charged scalar particle,
violate the lepton number. The quantity of different channels are calculated, where
, , and are parameters related to the
doubly-charged scalar. For ,
, and , it is of the order of , , and
, respectively. Based on the experimental results for the
channels, we also set the upper limit for
.Comment: 15 pages, 2 figure
The Properties of
The new particle has stimulated many attentions. There
are different assignments of its inherent properties. It may be a ,
or the mixture of state. By
considering its mass, decay modes, full width, production rate, and comparing
with current experimental data, we point out that there is another more
reasonable assignment: could be identified as two
resonances, one of which is a state, another is a 1D state, and both
are states. The two states have very close masses, which are
around 2700 MeV, and both have broad decay widths. So in experiments, the
overlapping of or invariant mass distribution coming from their
decays is found, but the current experiments could not distinguish these two
resonances and reported one particle.Comment: 12 pages, 3 figure
Annihilation rate of charmonium and bottomonium
The state is the ground state of spin-singlet D-wave
charmonia. Although it has not been found yet, the experimental data accumulate
rapidly. This charmonium attracts more and more attention, especially when the
BaBar Collaboration finds that the X(3872) particle has negative parity. In
this paper we calculate the double-gamma and double-gluon annihilation
processes of charmonia and bottomonia by using the instantaneous
Bethe-Salpeter method. We find the relativistic corrections make the decay
widths of 25 times smaller than the non-relativistic
results. If this state is below the threshold, we can use the
sum of annihilation widths and EM transition widths to estimate the total decay
width. Our result for with GeV is
keV. The dominant decay channel , whose
branching ratio is about 90%, can be used to discover this state.Comment: 10 pages, 2 figure
Optimization and analysis of large scale data sorting algorithm based on Hadoop
When dealing with massive data sorting, we usually use Hadoop which is a
framework that allows for the distributed processing of large data sets across
clusters of computers using simple programming models. A common approach in
implement of big data sorting is to use shuffle and sort phase in MapReduce
based on Hadoop. However, if we use it directly, the efficiency could be very
low and the load imbalance can be a big problem. In this paper we carry out an
experimental study of an optimization and analysis of large scale data sorting
algorithm based on hadoop. In order to reach optimization, we use more than 2
rounds MapReduce. In the first round, we use a MapReduce to take sample
randomly. Then we use another MapReduce to order the data uniformly, according
to the results of the first round. If the data is also too big, it will turn
back to the first round and keep on. The experiments show that, it is better to
use the optimized algorithm than shuffle of MapReduce to sort large scale data
Exploiting Multi-typed Treebanks for Parsing with Deep Multi-task Learning
Various treebanks have been released for dependency parsing. Despite that
treebanks may belong to different languages or have different annotation
schemes, they contain syntactic knowledge that is potential to benefit each
other. This paper presents an universal framework for exploiting these
multi-typed treebanks to improve parsing with deep multi-task learning. We
consider two kinds of treebanks as source: the multilingual universal treebanks
and the monolingual heterogeneous treebanks. Multiple treebanks are trained
jointly and interacted with multi-level parameter sharing. Experiments on
several benchmark datasets in various languages demonstrate that our approach
can make effective use of arbitrary source treebanks to improve target parsing
models.Comment: 11 pages, 4 figure
The Strong Decays of Orbitally Excited Mesons by Improved Bethe-Salpeter Method
We calculate the masses and the strong decays of orbitally excited states
, , and by the improved Bethe-Salpeter
method. The predicted masses of and are
, . We
calculate the isospin symmetry violating decay processes
and through mixing and get small widths.
Considering the uncertainties of the masses, for and , we
also calculate the OZI allowed decay channels: and
. For and , the OZI allowed decay
channels , and are studied. In all the decay channels, the reduction formula, PCAC relation
and low energy theorem are used to estimate the decay widths. We also obtain
the strong coupling constants , ,
, , ,
, , ,
and .Comment: 21 pages, 1 figure, 4 table
-Wave Charmonia (), (), and () in Decays
We study the semi-leptonic and non-leptonic decays of meson to -wave
charmonia, namely, , , and
. In our calculations, the instantaneous Bethe-Salpeter
method is applied to achieve the hadronic matrix elements. This method includes
relativistic corrections which are important especially for the higher orbital
excited states. For the semi-leptonic decay channels with electron as the final
lepton, we get the branching ratios , , and
. The transition form factors, forward-backward asymmetries, and lepton
spectra in these processes are also presented. For the non-leptonic decay
channels, those with as the lighter meson have the largest branching
ratios, , , and .Comment: 18 pages, 9 figure
Weak Decays of and
In this paper we study the weak decays of and . Using
the Bethe-Salpeter method, we calculate the hadronic transition amplitude and
give the form factors. We find that two new form factors and , which
do not appear in existing literature, have contributions in
decays. They affect the branching ratios of semi-leptonic and non-leptonic
decays by the rate of and , respectively, so their
contributions can not be ignored and should be considered. Our results show
that, for the semi-leptonic decay modes, the largest branching ratios are of
the order of both for and decays, and the
largest branching ratios of non-leptonic decays are of the order of
for and for .Comment: 26 pages, 12 figures, 17 table
The Production of and in decays
Considering and as and , we
study the productions of and in exclusive weak decays of
meson by the improved Bethe-Salpeter(B-S) Method. Using the relativistic
B-S equation and Mandelstam formalism, we calculate the corresponding decay
form factors. The predictions of the corresponding branching ratios are:
and . That will provide us a new way to observe
the and in the future, as well as to improve the knowledge
of meson decay.Comment: 15 pages, 7 figure
The weak decay to and by Bethe-Salpeter method
Considering and as and
states, the semileptonic and nonleptonic of decays to and
are studied by the improved Bethe-Salpeter(B-S) Method. The form
factors of decay are calculated through the overlap integrals of the meson wave
functions in the whole accessible kinematical range. The influence of
relativistic corrections are considered in the exclusive decays. Branching
ratios of weak decays to and are predicted. Some of
the branching ratios are: and . These results may
provide useful information to discover and and the
necessary information for the phenomenological study of physics.Comment: arXiv admin note: substantial text overlap with arXiv:1605.0909
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