23,954 research outputs found
The line shape of the radiative open-charm decay of Y(4140) and Y(3930)
In this work, we study the radiative open-charm decays and under the
assignments of and as molecular states for
Y(4140) and Y(3930) respectively. Based on our numerical result, we propose the
experimental measurement of the photon spectrum of and can further test the
molecular assignment for Y(4140) and Y(3930).Comment: 4 pages, 4 figures. More references and discussions added, typos
corrected. Accepted by Phys. Rev.
Spatiotemporal variation in precipitation during rainy season in Beibu Gulf, South China, from 1961 to 2016
The spatiotemporal variation in precipitation is an important part of water cycle change, which is directly associatedwith the atmospheric environment and climate change. The high-resolution spatiotemporal change of precipitation is still unknown inmany areas despite its importance. This study analyzed the spatiotemporal variation in precipitation in Beibu Gulf, South China, during the rainy season (fromApril to September) in the period of 1961–2016. The precipitation datawere collected from 12 national standard rain-gauge observation stations. The spatiotemporal variation in precipitation was evaluated with incidence rate and contribution rate of precipitation. The tendency of variations was analyzed using the Mann–Kendall method. The precipitation in the rainy season contributed 80% to the total annual precipitation. In general, there was an exponential decreasing tendency between the precipitation incidence rate and increased precipitation durations. The corresponding contribution rate showed a downward trend after an initial increase. The precipitation incidence rate decreased with the rising precipitation grades, with a gradual increase in contribution rate. The precipitation incidence rate and contribution rate of 7–9 d durations showed the significant downward trends that passed the 95% level of significance test. The results provide a new understanding of precipitation change in the last five decades, which is valuable for predicting future climate change and extreme weather prevention and mitigation
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Review of computer vision in intelligent environment design
This paper discusses and compares the use of vision based and non-vision based technologies in developing intelligent environments. By reviewing the related projects that use vision based techniques in intelligent environment design, the achieved functions, technical issues and drawbacks of those projects are discussed and summarized, and the potential solutions for future improvement are proposed, which leads to the prospective direction of my PhD research
Re-Study on the wave functions of states in LFQM and the radiative decays of
The Light-front quark model (LFQM) has been applied to calculate the
transition matrix elements of heavy hadron decays. However, it is noted that
using the traditional wave functions of the LFQM given in literature, the
theoretically determined decay constants of the obviously
contradict to the data. It implies that the wave functions must be modified.
Keeping the orthogonality among the states and fitting their decay
constants we obtain a series of the wave functions for . Based on
these wave functions and by analogy to the hydrogen atom, we suggest a modified
analytical form for the wave functions. By use of the modified
wave functions, the obtained decay constants are close to the experimental
data. Then we calculate the rates of radiative decays of . Our predictions are consistent with the experimental data on
decays within the theoretical and experimental
errors.Comment: 10 pages, 2 figures, 1 table. Typos corrected and more discussions
added. accepted for publication in Physical Review
Exploring open-charm decay mode of charmonium-like state
The newly observed exotic states are definitely not in the standard
structures, thus their existence composes a challenge to our
understanding on the fundamental principles of hadron physics. Therefore the
studies on their decay patterns which are determined by the non-perturbative
QCD will definitely shed light on the concerned physics. Generally the
four-quark states might be in a molecular state or tetraquark or their mixture.
In this work, we adopt the suggestion that is a charmonium-like
tetraquark made of a diquark and an anti-diquark. If it is true, its favorable
decay mode should be decaying into an open-charm baryon pair, since
such a transition occurs via strong interaction and is super-OZI-allowed. In
this work, we calculate the decay width of
in the framework of the quark pair creation (QPC) model. Our numerical results
on the partial width computed in the tetraquark configuration coincide with the
Belle data within a certain error tolerance.Comment: 8 pages, 4 figures, 1 table. Accepted by Eur. Phys. J.
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