2,338 research outputs found
On the Unitarity Triangles of the CKM Matrix
The unitarity triangles of the Cabibbo-Kobayashi-Maskawa (CKM)
matrix are studied in a systematic way. We show that the phases of the nine CKM
rephasing invariants are indeed the outer angles of the six unitarity triangles
and measurable in the -violating decay modes of and mesons.
An economical notation system is introduced for describing properties of the
unitarity triangles. To test unitarity of the CKM matrix we present some
approximate but useful relations among the sides and angles of the unitarity
triangles, which can be confronted with the accessible experiments of quark
mixing and violation.Comment: 9 Latex pages; LMU-07/94 and PVAMU-HEP-94-5 (A few minor changes are
made, accepted for publication in Phys. Lett. B
F-wave heavy-light meson spectroscopy in QCD sum rules and heavy quark effective theory
We study the F-wave c_bar s heavy meson doublets (2+,3+) and (3+,4+). They
have large orbital excitations L=3, and may be good challenges (tests) for
theoretical studies. To study them we use the method of QCD sum rule in the
framework of heavy quark effective theory. Their masses are predicted to be
m_{(2+,3+)} = (3.45 \pm 0.25, 3.50 \pm 0.26) GeV and m_{(3+,4+)} = (3.20 \pm
0.22, 3.26 \pm 0.23) GeV, with mass splittings Delta m_{(2+,3+)} = m_{3+} -
m_{2+} = 0.046 \pm 0.030 GeV and Delta m_{(3+,4+)} = 0.053 \pm 0.044 GeV,
respectively. We note that this is a pioneering work and these results are
provisional.Comment: 10 pages, 8 figures, 3 tables, accepted by PR
The Relation of Thermal Fluctuation and Information-Entropy for One-Dimensional Rindler Oscillator
Within the framework of thermo-field-dynamics (TFD), the
information-entropies associated with the measurements of position and momentum
for one-dimensional Rindler oscillator are derived, and the connection between
its information-entropy and thermal fluctuation is obtained. A conclusion is
drawn that the thermal fluctuation leads to the loss of information.Comment: 14 pages, 1 figur
Dynamic asset allocation with uncertain jump risks : a pathwise optimization approach
This paper studies the dynamic portfolio choice problem with ambiguous jump risks in a multi-dimensional jump-diffusion framework. We formulate a continuous-time model of incomplete market with uncertain jumps. We develop an efficient pathwise optimization procedure based on the martingale methods and
minimax results to obtain closed-form solutions for the indirect utility function and the probability of the worst scenario. We then introduce an orthogonal decomposition method for the multi-dimensional problem to derive the optimal portfolio strategy explicitly under ambiguity aversion to jump risks. Finally, we calibrate our model to real market data drawn from ten international indices and illustrate our results by numerical examples. The certainty equivalent losses affirm the importance of jump uncertainty in optimal portfolio choice
Trajectory Envelope of a Subsea Shuttle Tanker Hovering in Stochastic Ocean Current - Model Development and Tuning
A subsea shuttle tanker (SST) concept for liquid carbon dioxide transportation was recently proposed to support studies evaluating the ultra-efficient underwater cargo submarine concept. One important topic is the position keeping ability of SST during the offloading process. In this process, the SST hovers above the well and connects with the wellhead using a flowline. This process takes around 4 h. Ocean currents can cause tremendous drag forces on the subsea shuttle tanker during this period. The flow velocities over hydroplanes are low throughout this process, and the generated lift forces are generally insufficient to maintain the SST’s depth. The ballast tanks cannot provide such fast actuation to cope with the fluctuation of the current. It is envisioned that tunnel thrusters that can provide higher frequency actuation are required. This paper develops a maneuvering model and designs a linear quadratic regulator that facilitates the SST station-keeping problem in stochastic current. As case studies, the SST footprints at 0.5 m/s, 1.0 m/s, and 1.5 m/s mean current speeds are presented. Numerical results show that the designed hovering control system can ensure the SST’s stationary during offloading. The required thrust from thrusters and the propeller are presented. The presented model can serve as a basis for obtaining a more efficient design of the SST and provide recommendations for the SST operation.acceptedVersio
Modeling method of failure dependent system based on time varying copula function
This paper aims at solving the dynamic correlation of the complex dependence system with multiple failures. A correlation model and parameter estimation method based on time-varying copula function are proposed to solve the joint distribution between the interaction mechanism. In particular, three types of definition method for the time-varying copulas’ parameters are introduced. Finally, a comparative study and applicability analysis are performed to validate our proposed method
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