5,297 research outputs found
Understanding the nature of and through nonleptonic B Decays
We consider the nonleptonic B decays and , involving the newly discovered and the
states. We find that experiments indicate disagreement with model
calculations of their properties and/or breakdown of the factorization
assumption for these decays . We point out that decays involving mesons
where the resonances can be produced via the weak decay of the quark
can provide further information about the nature of these newly discovered
states. We also propose a model to calculate the two body nonleptonic decays , if the and are
interpreted as and molecules.Comment: 14 pages LaTeX; additional reference, notational corrections and
minor clarifications of tex
Extraction of Spectral Functions from Dyson-Schwinger Studies via the Maximum Entropy Method
It is shown how to apply the Maximum Entropy Method (MEM) to numerical
Dyson-Schwinger studies for the extraction of spectral functions of correlators
from their corresponding Euclidean propagators. Differences to the application
in lattice QCD are emphasized and, as an example, the spectral functions of
massless quarks in cold and dense matter are presented.Comment: 16 pages, 7 figure
Spectral properties of quarks above T_c in quenched lattice QCD
We analyze the quark spectral function above the critical temperature for
deconfinement in quenched lattice QCD using clover improved Wilson fermions in
Landau gauge. We show that the temporal quark correlator is well reproduced by
a two-pole approximation for the spectral function and analyze the bare quark
mass dependence of both poles as well as their residues. In the chiral limit we
find that the quark spectral function has two collective modes which correspond
to the normal and plasmino excitations. At large values of the bare quark mass
the spectral function is dominated by a single pole.Comment: 5 pages, 3 figures, typos corrected, references adde
vs.
Recent experimental results for the ratio of the branching fractions of and decays
came as a surprise and lead to a discussion of possibility to constraining New
Physics through these modes. Here we focus on and argue that the result is
consistent with the Standard Model within , and that the test of
compatibility of this ratio with the Standard Model can be done experimentally
with a minimal theory input. We also show that these two decay channels can
provide us with quite good constraints of the New Physics couplings.Comment: 10 pages (published version
Fractal Fluctuations and Quantum-Like Chaos in the Brain by Analysis of Variability of Brain Waves: A New Method Based on a Fractal Variance Function and Random Matrix Theory
We developed a new method for analysis of fundamental brain waves as recorded
by EEG. To this purpose we introduce a Fractal Variance Function that is based
on the calculation of the variogram. The method is completed by using Random
Matrix Theory. Some examples are given
A note on possible interpretations for the observed by SELEX
We suggest some possible interpretations for the observed by
SELEX. The could be the first radial excitation of the
ground state (2112), and its unusual decay patten might be
hopefully explained by the node structure of the wave functions. In addition,
the could also be a hybrid state or a
(diquark-antidiquark) bound state.Comment: final version to appear in Phys. Lett. B, references adde
Meson correlation functions in a QCD plasma
The temporal pseudoscalar meson correlation function in a QCD plasma is
investigated in a range of temperatures exceeding and yet of experimental
interest. Only the flavour-singlet channel is considered and the imaginary time
formalism is employed for the finite temperature calculations. The behaviour of
the meson spectral function and of the temporal correlator is first studied in
the HTL approximation, where one replaces the free thermal quark propagators
with the HTL resummed ones. This procedure satisfactory describes the soft
fermionic modes, but its application to the propagation of hard quarks is not
reliable. An improved version of the so-called NLA scheme, which allows a
better treatment of the hard fermionic modes, is then proposed. The impact of
the improved NLA on the pseudoscalar temporal correlator is investigated.Comment: 35 pages, 15 figure
Static correlation lengths in QCD at high temperature and finite density
A brief review is given of the sign problem in finite density lattice QCD and
various attempts to overcome it. To date there is still no solution to this
problem which would work for realistic QCD. The main focus then is on the
deconfined phase, where QCD can be described by a dimensionally reduced
effective action. After summarizing derivation and validity of the effective
theory, it is demonstrated that it can be simulated efficiently in the presence
of a chemical potential for quarks \mu/T\lsim 4. Direct comparison of
simulations with imaginary and real suggests that equilibrium plasma
properties could be analytically continued from 4d QCD simulations at imaginary
.Comment: Lattice 2000 (plenary), 12 pages, 9 figures, typos corrected, Fig.7
replaced by black and whit
Study of CP violation in D->VV decay at BESIII
In this paper, we intend to study the problem of CP violation in meson by
decay mode in which the T violating triple-product correlation is
examined. That would undoubtedly be another excellent probe of New Physics
beyond Standard Model. For the neutral , we focus on direct CP violation
without considering oscillation. Experimentally, by a full
angular analysis one may obtain such CP violating signals, and particularly it
is worth mentioning that the upcoming large data samples at BES-III in
Beijing will provide a great opportunity to perform it.Comment: 5 pages, 2 tables and 1 figure, version to appear in Phys. Lett.
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