5,095 research outputs found
Lepton flavor violating decays induced by scalar unparticle
We study the radiative lepton flavor violating l_i -> l_j \gamma\gamma decays
in the case that the lepton flavor violation is induced by the scalar
unparticle mediation. We restrict the scaling dimension d_u and the scalar
unparticle-photon-photon coupling by using the experimental upper limit of the
branching ratio of the decay \mu -> e \gamma\gamma. Furthermore, we predict the
BRs of the other radiative decays by using the restrictions we get. We observe
that the measurements of upper limits of BRs of these decays ensure
considerable information for testing the possible signals coming from
unparticle physicsComment: 10 pages, 5 figures, 1 tabl
Exact Solutions in Five-Dimensional Axi-dilaton Gravity with Euler-Poincare Term
We examine the effective field equations that are obtained from the
axi-dilaton gravity action with a second order Euler-Poincare term and a
cosmological constant in all higher dimensions. We solve these equations for
five-dimensional spacetimes possessing homogeneity and isotropy in their
three-dimensional subspaces. For a number of interesting special cases we show
that the solutions fall into two main classes: The first class consists of
time-dependent solutions with spherical or hyperboloidal symmetry which require
certain fine-tuning relations between the coupling constants of the model and
the cosmological constant. Solutions in the second class are locally static and
prove the validity of Birkhoff's staticity theorem in the axi-dilaton gravity.
We also give a special class of static solutions, among them the well-known
black hole solutions in which the usual electric charge is superseded by an
axion charge.Comment: New formulas and references adde
The scalar unparticle effect on the charged lepton electric dipole moment
We study the charged lepton electric dipole moment which is induced by the
scalar unparticle mediation and we predict the appropriate range for the free
parameters appearing in the effective lagrangian which drives the
unparticle-standard model lepton interactions. We observe that the charged
lepton electric dipole moment is strongly sensitive to the scaling dimension
d_u of the unparticle and the new couplings in the effective interaction.
Furthermore, we see that the current experimental limits of charged lepton
electric dipole moments can ensure an appropriate range for these free
parameters.Comment: 19 pages, 13 Figure
Dynamical systems of M\"obius transformation: real, -adic and complex variables
In this paper we consider function , (where ,
, ) on three fields: the set of real, -adic and
complex numbers. We study dynamical systems generated by this function on each
field separately and give some comparison remarks.
For real variable case we show that the real dynamical system of the function
depends on the parameters . Namely, we classify the
parameters to three sets and prove that: for the parameters from first class
each point, for which the trajectory is well defined, is a periodic point of
; for the parameters from second class any trajectory (under ) converges
to one of fixed points (there may be up to two fixed points); for the
parameters from third class any trajectory is dense in .
For the -adic variable we give a review of known results about dynamical
systems of function . Then using a recently developed method we give simple
new proofs of these results and prove some new ones related to trajectories
which do not converge.
For the complex variables we give a review of known results.Comment: 13 page
Investigation of heavy-heavy pseudoscalar mesons in thermal QCD Sum Rules
We investigate the mass and decay constant of the heavy-heavy pseudoscalar,
, and mesons in the framework of finite temperature QCD
sum rules. The annihilation and scattering parts of spectral density are
calculated in the lowest order of perturbation theory. Taking into account the
additional operators arising at finite temperature, the nonperturbative
corrections are also evaluated. The masses and decay constants remain unchanged
under , but after this point, they start to diminish with
increasing the temperature. At critical or deconfinement temperature, the decay
constants reach approximately to 35% of their values in the vacuum, while the
masses are decreased about 7%, 12% and 2% for , and
states, respectively. The results at zero temperature are in a good consistency
with the existing experimental values as well as predictions of the other
nonperturbative approaches.Comment: 11 Pages, 2 Tables and 6 Figure
New physics effects to the lepton polarizations in the B -> K l^+ l^- decay
Using the general, model independent form of the effective Hamiltonian, the
general expressions of the longitudinal, normal and transversal polarization
asymmetries for (l^-) and (l^+) and combinations of them for the exclusive (B
-> K l^+ l^-) decay are found. The sensitivity of lepton polarizations and
their combinations on new Wilson coefficients are studied. It is found that
there exist regions of Wilson coefficients for which the branching ratio
coincides with the Standard Model result while the lepton polarizations differ
substantially from the standard model prediction. Hence, studying lepton
polarization in these regions of new Wilson coefficients can serve as a
promising tool for establishing new physics beyond the Standard Model.Comment: 18 pp, 14 figures (postscript formatted), LaTex formatte
Vacuum Fluctuations of a massless spin-1/2 field around multiple cosmic strings
We study the interaction of a massless quantized spinor field with the
gravitational filed of N parallel static cosmic strings by using a perturbative
approach. We show that the presence of more than one cosmic string gives rise
to an additional contribution to the energy density of vacuum fluctuations,
thereby leading to a vacuum force attraction between two parallel cosmic
strings.Comment: Class. Quantum Grav. 14(1997) 321
B --> K^* \tau^+ \tau^- decay in the general two Higgs doublet model including the neutral Higgs boson effects
We study the CP violating asymmetry, the forward-backward asymmetry of the
lepton pair and the CP asymmetry in the forward backward asymmetry for the
exclusive decay $B --> K^* \tau^+ \tau^- in the general two Higgs doublet model
including the neutral Higgs boson effects. We analyse the dependencies of these
quantities on the model III parameters. We found that the physical parameters
studied above are at the order of the magnitude 1% and neutral Higgs boson
effects are detectable for large values of the coupling
\bar{\xi}_{N,\tau\tau}^D.Comment: 20 pages, 11 Figure
Topologically massive magnetic monopoles
We show that in the Maxwell-Chern-Simons theory of topologically massive
electrodynamics the Dirac string of a monopole becomes a cone in anti-de Sitter
space with the opening angle of the cone determined by the topological mass
which in turn is related to the square root of the cosmological constant. This
proves to be an example of a physical system, {\it a priory} completely
unrelated to gravity, which nevertheless requires curved spacetime for its very
existence. We extend this result to topologically massive gravity coupled to
topologically massive electrodynamics in the framework of the theory of Deser,
Jackiw and Templeton. These are homogeneous spaces with conical deficit. Pure
Einstein gravity coupled to Maxwell-Chern-Simons field does not admit such a
monopole solution
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