47,137 research outputs found
New Formulas and Predictions for Running Fermion Masses at Higher Scales in SM, 2HDM, and MSSM
Including contributions of scale-dependent vacuum expectation values, we
derive new analytic formulas and obtain substantially different numerical
predictions for the running masses of quarks and charged-leptons at higher
scales in the SM, 2HDM and MSSM. These formulas exhibit significantly different
behaviours with respect to their dependence on gauge and Yukawa couplings than
those derived earlier. At one-loop level the masses of the first two
generations are found to be independent of Yukawa couplings of the third
generation in all the three effective theories in the small mixing limit.
Analytic formulas are also obtained for running in 2HDM and
MSSM. Other numerical analyses include study of the third generation masses at
high scales as functions of low-energy values of and SUSY scale
GeV.Comment: 42 pages RevTeX, including 16 figures. Typos corrected and one
reference adde
Comparison of Canonical and Grand Canonical Models for selected multifragmentation data
Calculations for a set of nuclear multifragmentation data are made using a
Canonical and a Grand Canonical Model. The physics assumptions are identical
but the Canonical Model has an exact number of particles, whereas, the Grand
Canonical Model has a varying number of particles, hence, is less exact.
Interesting differences are found.Comment: 12 pages, Revtex, and 3 postscript figure
Spatial persistence and survival probabilities for fluctuating interfaces
We report the results of numerical investigations of the steady-state (SS)
and finite-initial-conditions (FIC) spatial persistence and survival
probabilities for (1+1)--dimensional interfaces with dynamics governed by the
nonlinear Kardar--Parisi--Zhang (KPZ) equation and the linear
Edwards--Wilkinson (EW) equation with both white (uncorrelated) and colored
(spatially correlated) noise. We study the effects of a finite sampling
distance on the measured spatial persistence probability and show that both SS
and FIC persistence probabilities exhibit simple scaling behavior as a function
of the system size and the sampling distance. Analytical expressions for the
exponents associated with the power-law decay of SS and FIC spatial persistence
probabilities of the EW equation with power-law correlated noise are
established and numerically verified.Comment: 11 pages, 5 figure
Nonequilibrium Dynamics of the Complex Ginzburg-Landau Equation. I. Analytical Results
We present a detailed analytical and numerical study of nonequilibrium
dynamics for the complex Ginzburg-Landau (CGL) equation. In particular, we
characterize evolution morphologies using spiral defects. This paper (referred
to as ) is the first in a two-stage exposition. Here, we present
analytical results for the correlation function arising from a single-spiral
morphology. We also critically examine the utility of the Gaussian auxiliary
field (GAF) ansatz in characterizing a multi-spiral morphology. In the next
paper of this exposition (referred to as ), we will present detailed
numerical results.Comment: 21 pages, 7 figure
Instability, Intermittency and Multiscaling in Discrete Growth Models of Kinetic Roughening
We show by numerical simulations that discretized versions of commonly
studied continuum nonlinear growth equations (such as the Kardar-Parisi-Zhang
equation and the Lai-Das Sarma equation) and related atomistic models of
epitaxial growth have a generic instability in which isolated pillars (or
grooves) on an otherwise flat interface grow in time when their height (or
depth) exceeds a critical value. Depending on the details of the model, the
instability found in the discretized version may or may not be present in the
truly continuum growth equation, indicating that the behavior of discretized
nonlinear growth equations may be very different from that of their continuum
counterparts. This instability can be controlled either by the introduction of
higher-order nonlinear terms with appropriate coefficients or by restricting
the growth of pillars (or grooves) by other means. A number of such
``controlled instability'' models are studied by simulation. For appropriate
choice of the parameters used for controlling the instability, these models
exhibit intermittent behavior, characterized by multiexponent scaling of height
fluctuations, over the time interval during which the instability is active.
The behavior found in this regime is very similar to the ``turbulent'' behavior
observed in recent simulations of several one- and two-dimensional atomistic
models of epitaxial growth. [pacs{61.50.Cj, 68.55.Bd, 05.70.Ln, 64.60.Ht}]Comment: 47 pages + 26 postscript figures, submitted to Phys. Rev.
Structure of potentials with Higgs doublets
Extensions of the Standard Model with Higgs doublets are simple
extensions presenting a rich mathematical structure. An underlying Minkowski
structure emerges from the study of both variable space and parameter space.
The former can be completely parametrized in terms of two future lightlike
Minkowski vectors with spatial parts forming an angle whose cosine is
. For the parameter space, the Minkowski parametrization enables
one to impose sufficient conditions for bounded below potentials, characterize
certain classes of local minima and distinguish charge breaking vacua from
neutral vacua. A particular class of neutral minima presents a degenerate mass
spectrum for the physical charged Higgs bosons.Comment: 11 pages. Revtex4. Typos corrected. Few comments adde
Caloric curve in Au + Au collisions
Realistic caloric curves are obtained for reaction with
incident energy ranging from 35 to 130 MeV/nucleon in the dynamic statistical
multifragmentation model. It is shown that for excitation energy 3 to 8
MeV/nucleon, the temperature remains constant in the range 5 to 6 MeV, which is
close to experiment. The mechanism of energy deposition through the
tripartition of colliding system envisaged in this model together with
inter-fragment nuclear interaction are found to play important role. A possible
signature of liquid-gas phase transition is seen in the specific heat
distribution calculated from these caloric curves, and the critical temperature
is found to be 6 to 6.5 MeV.Comment: Revtex, 10 pages, 4 postscipt figures, To appear in Phys. Rev. C
(Rapid Communications
The radiation equation of state and loop quantum gravity corrections
The equation of state for radiation is derived in a canonical formulation of
the electromagnetic field. This allows one to include correction terms expected
from canonical quantum gravity and to infer implications to the universe
evolution in radiation dominated epochs. Corrections implied by quantum
geometry can be interpreted in physically appealing ways, relating to the
conformal invariance of the classical equations.Comment: 11 pages, 1 figur
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