3,732 research outputs found
The Viscous Lengths in Hydrodynamic Turbulence are Anomalous Scaling Functions
It is shown that the idea that scaling behavior in turbulence is limited by
one outer length and one inner length is untenable. Every n'th order
correlation function of velocity differences \bbox{\cal
F}_n(\B.R_1,\B.R_2,\dots) exhibits its own cross-over length to
dissipative behavior as a function of, say, . This length depends on
{and on the remaining separations} . One result of this Letter
is that when all these separations are of the same order this length scales
like with
, with being
the scaling exponent of the 'th order structure function. We derive a class
of scaling relations including the ``bridge relation" for the scaling exponent
of dissipation fluctuations .Comment: PRL, Submitted. REVTeX, 4 pages, I fig. (not included) PS Source of
the paper with figure avalable at http://lvov.weizmann.ac.il/onlinelist.htm
Micro-Capsules in Shear Flow
This paper deals with flow-induced shape transitions of elastic capsules. The
state of the art concerning both theory and experiments is briefly reviewed
starting with dynamically induced small deformation of initially spherical
capsules and the formation of wrinkles on polymerized membranes. Initially
non-spherical capsules show tumbling and tank-treading motion in shear flow.
Theoretical descriptions of the transition between these two types of motion
assuming a fixed shape are at variance with the full capsule dynamics obtained
numerically. To resolve the discrepancy, we expand the exact equations of
motion for small deformations and find that shape changes play a dominant role.
We classify the dynamical phase transitions and obtain numerical and analytical
results for the phase boundaries as a function of viscosity contrast, shear and
elongational flow rate. We conclude with perspectives on timedependent flow, on
shear-induced unbinding from surfaces, on the role of thermal fluctuations, and
on applying the concepts of stochastic thermodynamics to these systems.Comment: 34 pages, 15 figure
Resonance structure in the {\gamma}{\gamma} and systems in dC interactions
Along with and {\eta} mesons, a resonance structure in the invariant
mass spectrum of two photons at M{\gamma}{\gamma} = 360 \pm 7 \pm 9 MeV is
observed in the reaction d + C \rightarrow {\gamma} + {\gamma} + X at momentum
2.75 GeV/c per nucleon. Estimates of its width and production cross section are
{\Gamma} = 64 \pm 18 MeV and = 98 \pm 24 {\mu}b,
respectively. The collected statistics amount to 2339 \pm 340 events of 1.5
\cdot 10^6 triggered interactions of a total number ~ 10^12 of dC-interactions.
The results on observation of the resonance in the invariant mass spectra of
two mesons are presented: the data obtained in the d + C \rightarrow
{\gamma} + {\gamma} reaction is confirmed by the d + C \rightarrow +
reaction: = 359.2 \pm 1.9 MeV, {\Gamma} = 48.9 \pm 4.9
MeV; the ratio of Br(R\rightarrow{\gamma}{\gamma}) /
Br(R\rightarrow) = (1.8 {\div} 3.7)\cdot10^-3.Comment: 10 pages, 11 figure
Bulk viscosity of superfluid neutron stars
The hydrodynamics, describing dynamical effects in superfluid neutron stars,
essentially differs from the standard one-fluid hydrodynamics. In particular,
we have four bulk viscosity coefficients in the theory instead of one. In this
paper we calculate these coefficients, for the first time, assuming they are
due to non-equilibrium beta-processes (such as modified or direct Urca
process). The results of our analysis are used to estimate characteristic
damping times of sound waves in superfluid neutron stars. It is demonstrated
that all four bulk viscosity coefficients lead to comparable dissipation of
sound waves and should be considered on the same footing.Comment: 11 pages, 1 figure, this version with some minor stylistic changes is
published in Phys. Rev.
Spontaneous Violation of the CP Symmetry in the Higgs Sector of the Next-to-Minimal Supersymmetric Model
The spontaneous violation of the CP symmetry in the next-to-minimal
supersymmetric standard Model (NMSSM) is investigated. It is found that the
spontaneous violation of the CP symmetry can occur in the Higgs sector of the
NMSSM for a wide region of the parameter space of the model, at the 1-loop
level where the radiative corrections due to the top quark and scalar-top quark
loops are found to generate the scalar-pseudoscalar mixings between the two
Higgs doublets of the NMSSM. In our model, we assume that the masses of the
left-handed and the right-handed scalar-top quarks are not degenerate. And we
investigate our model anaytically: We derive analytical formulae of the 1-loop
mass matrix for the neutral Higgs bosons. We calculate the upper bound on the
lightest neutral Higgs boson mass under the assumption. It is found to be about
140 GeV for our choice of parameter values in the presence of the spontaneous
violation of the CP symmetry in the NMSSM. Thus, the possibility of the
spontaneous violation of the CP symmetry is not completely ruled out in the
Higgs sector of the NMSSM if the masses of the left-handed and the right-handed
scalar-top quarks are not degenerate. Further, the phenomenology of the
- mixing within the context of our model is studied. The lower
bound on CP violating phase in the - mixing is found to increase
if either decreases or increases.Comment: 21 pages, 5 figures, To appear in Phys. Rev.
Possibility of spontaneous CP violation in the nonminimal supersymmetric standard model with two neutral Higgs singlets
A supersymmetric standard model with two Higgs doublets and two Higgs
singlets is investigated if it can accommodate the possibility of spontaneous
CP violation. Assuming the degeneracy of the scalar quark masses of the third
generation, we find that spontaneous CP violation in the Higgs sector is viable
in our model. In the case of spontaneous CP violation, the masses of the
lightest two neutral Higgs bosons are estimated to be 80 and 125 GeV for some
parameter values in our model, which, are consistent with LEP2 data.Comment: 18 pages, 3figure
Neutral Higgs sector of the next-to-minimal supersymmetric standard model with explicit CP violation
The neutral Higgs sector of the next-to-minimal supersymmetric standard model
(NMSSM) with explicit CP violation is investigated at the 1-loop level, using
the effective potential method; not only the loops involving the third
generation of quarks and scalar quarks, but also the loops involving boson,
charged Higgs boson, and chargino are taken into account. It is found that for
some parameter values of the NMSSM the contributions from the boson,
charged Higgs boson, and chargino loops may modify the masses of the neutral
Higgs bosons and the mixings among them significantly, depending on the CP
phase. In collisions, the prospects for discovering neutral Higgs
bosons are investigated within the context of the NMSSM with explicit CP
violation when the dominant component of the lightest neutral Higgs boson is
the Higgs singlet field of the NMSSM.Comment: Latex, 23 pages, 6 figure
Electron injection in a nanotube with leads: finite frequency noise-correlations and anomalous charges
The non-equilibrium transport properties of a carbon nanotube which is
connected to Fermi liquid leads, where electrons are injected in the bulk, are
computed. A previous work which considered an infinite nanotube showed that the
zero frequency noise correlations, measured at opposite ends of the nanotube,
could be used to extract the anomalous charges of the chiral excitations which
propagate in the nanotube. Here, the presence of the leads have the effect that
such-noise cross-correlations vanish at zero frequency. Nevertheless,
information concerning the anomalous charges can be recovered when considering
the spectral density of noise correlations at finite frequencies, which is
computed perturbatively in the tunneling amplitude. The spectrum of the noise
cross-correlations is shown to depend crucially on the ratio of the time of
flight of quasiparticles traveling in the nanotube to the ``voltage'' time
which defines the width of the quasiparticle wave-packets injected when an
electron tunnels. Potential applications toward the measurement of such
anomalous charges in non-chiral Luttinger liquids (nanotubes or semiconductor
quantum wires) are discussed.Comment: 11 pages, 5 figure
Invisible Higgs and Scalar Dark Matter
In this proceeding, we show that when we combined WMAP and the most recent
results of XENON100, the invisible width of the Higgs to scalar dark matter is
negligible(<10%), except in a small region with very light dark matter (< 10
GeV) not yet excluded by XENON100 or around 60 GeV where the ratio can reach
50% to 60%. The new results released by the Higgs searches of ATLAS and CMS set
very strong limits on the elastic scattering cross section.Comment: 4 pages, 2 figures, proceeding TAUP2011 References adde
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