Flavor physics in the quark sector Asner, D.M.; Bauer, D.; Becher, T. ...
Physics Reports,
2010, Letnik:
494, Številka:
3
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
In the past decade, one of the major challenges of particle physics has been to gain an in-depth understanding of the role of quark flavor. In this time frame, measurements and the theoretical ...interpretation of their results have advanced tremendously. A much broader understanding of flavor particles has been achieved; apart from their masses and quantum numbers, there now exist detailed measurements of the characteristics of their interactions allowing stringent tests of Standard Model predictions. Among the most interesting phenomena of flavor physics is the violation of the CP symmetry that has been subtle and difficult to explore. In the past, observations of CP violation were confined to neutral
K
mesons, but since the early 1990s, a large number of CP-violating processes have been studied in detail in neutral
B
mesons. In parallel, measurements of the couplings of the heavy quarks and the dynamics for their decays in large samples of
K
,
D
, and
B
mesons have been greatly improved in accuracy and the results are being used as probes in the search for deviations from the Standard Model.
In the near future, there will be a transition from the current to a new generation of experiments; thus a review of the status of quark flavor physics is timely. This report is the result of the work of physicists attending the 5th CKM workshop, hosted by the University of Rome “La Sapienza”, September 9–13, 2008. It summarizes the results of the current generation of experiments that are about to be completed and it confronts these results with the theoretical understanding of the field which has greatly improved in the past decade.
B meson decay constants from NRQCD Ali Khan, A.; Bhattacharya, T.; Collins, S. ...
Physics letters. B,
05/1998, Letnik:
427, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We present quenched results for
B meson decay constants using NRQCD
b quarks and
O(a)
tadpole improved clover light quarks. For the first time, one-loop matching factors between lattice and continuum ...currents are incorporated through
O(α/M
) taking operator mixing fully into account. This includes an important
O(α
a
) discretization correction to the heavy-light axial vector current. We find
f
B
=147(11)(
+8
−12)(9)(6) MeV and
f
B
s
/
f
B
=1.20(4)(
+4
−0).
Design method for a mini centrifugal pump is not established because the internal flow condition for these small-sized fluid machines is not clarified and conventional theory is not suitable for ...small-sized pumps. Then, a semi-open impeller for the mini centrifugal pump with 55mm impeller diameter is adopted in this research to take simplicity and maintenance into consideration. Splitter blades are adopted in this research to improve the per- formance and internal flow condition of mini centrifugal pump having large blade outlet angle. The performance tests are conducted with these rotors in order to investigate the effect of the splitter blades on the performance and internal flow condition of the mini centrifugal pump. A three dimensional steady numerical flow analysis is con- ducted to analyze rotor, volute efficiency and loss caused by a vortex. It is clarified from the experimental results that the performance of the mini centrifugal pump is improved by the effect of the splitter blades. Flow condition at outlet of the rotor becomes uniform and back flow regions are suppressed in the case with the splitter blades. Further, the volute efficiency increases and the vortex loss decreases. In the present paper, the performance of the mini centrifugal pump is shown and the flow condition is clarified with the results of the experiment and the nu- merical flow analysis. Furthermore, the performance analyses of the mini centrifugal pumps with and without the splitter blades are conducted.
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