28,174 research outputs found
Neutrino Masses and Mixing, Quark-lepton Symmetry and Strong Right-handed Neutrino Hierarchy
Assuming the same form of all mass matrices as motivated by quark-lepton
symmetry, we discuss conditions under which bi-large mixing in the lepton
sector can be obtained with a minimal amount of fine tuning requirements for
possible models. We assume hierarchical mass matrices, dominated by the 3-3
element, with off-diagonal elements much smaller than the larger neighboring
diagonal element. Characteristic features of this scenario are strong hierarchy
in masses of right-handed neutrinos, and comparable contributions of both
lighter right-handed neutrinos to the resulting left-handed neutrino Majorana
mass matrix. Due to obvious quark lepton symmetry, this approach can be
embedded into grand unified theories. The mass of the lightest neutrino does
not depend on details of a model in the leading order. The right-handed
neutrino scale can be identified with the GUT scale in which case the mass of
the lightest neutrino is given as (m_{top}^2/M_{GUT}) |U_{\tau 1}|^2.Comment: 7 page
Possible evidence of extended objects inside the proton
Recent experimental determinations of the Nachtmann moments of the inelastic
structure function of the proton F2p(x, Q**2), obtained at Jefferson Lab, are
analyzed for values of the squared four-momentum transfer Q**2 ranging from ~
0.1 to ~ 2 (GeV/c)**2. It is shown that such inelastic proton data exhibit a
new type of scaling behavior and that the resulting scaling function can be
interpreted as a constituent form factor consistent with the elastic nucleon
data. These findings suggest that at low momentum transfer the inclusive proton
structure function originates mainly from the elastic coupling with extended
objects inside the proton. We obtain a constituent size of ~ 0.2 - 0.3 fm.Comment: 1 reference adde
Numerical indications of a q-generalised central limit theorem
We provide numerical indications of the -generalised central limit theorem
that has been conjectured (Tsallis 2004) in nonextensive statistical mechanics.
We focus on binary random variables correlated in a {\it scale-invariant}
way. The correlations are introduced by imposing the Leibnitz rule on a
probability set based on the so-called -product with . We show
that, in the large limit (and after appropriate centering, rescaling, and
symmetrisation), the emerging distributions are -Gaussians, i.e., , with , and
with coefficients approaching finite values . The
particular case recovers the celebrated de Moivre-Laplace theorem.Comment: Minor improvements and corrections have been introduced in the new
version. 7 pages including 4 figure
Quasiclassical Equations of Motion for Nonlinear Brownian Systems
Following the formalism of Gell-Mann and Hartle, phenomenological equations
of motion are derived from the decoherence functional formalism of quantum
mechanics, using a path-integral description. This is done explicitly for the
case of a system interacting with a ``bath'' of harmonic oscillators whose
individual motions are neglected. The results are compared to the equations
derived from the purely classical theory. The case of linear interactions is
treated exactly, and nonlinear interactions are compared using classical and
quantum perturbation theory.Comment: 24 pages, CALT-68-1848 (RevTeX 2.0 macros
Orbifold Family Unification
We study the possibility of complete family unification in higher-dimensional
space-time. Three families of matters in SU(5) grand unified theory are derived
from a single bulk multiplet of SU(N) gauge group (N >= 9) in the framework of
S^1/Z_2 orbifold models. In the case of the direct orbifold breaking down to
the standard model gauge group, there are models in which bulk fields from a
single multiplet and a few brane fields compose three families of quarks and
leptons.Comment: Comments added, version to appear in Physical Review D (v3);
References added (v2); 19 pages (v1
Reactor antineutrino spectra and their application to antineutrino-induced reactions. II
The antineutrino and electron spectra associated with various nuclear fuels are calculated. While there are substantial differences between the spectra of different uranium and plutonium isotopes, the dependence on the energy and flux of the fission-inducing neutrons is very weak. The resulting spectra can be used for the calculation of the antineutrino and electron spectra of an arbitrary nuclear reactor at various stages of its refueling cycle. The sources of uncertainties in the spectrum are identified and analyzed in detail. The exposure time dependence of the spectrum is also discussed. The averaged cross sections of the inverse neutron β decay, weak charged and neutral-current-induced deuteron disintegration, and the antineutrino-electron scattering are then evaluated using the resulting ν̅_e spectra.
[RADIOACTIVITY, FISSION 235U, 238U, (^239)Pu, (^240)Pu, (^241)Pu, antineutrino and electron spectra calculated. σ for ν̅ induced reactions analyzed.
Statistical Mechanics of Relativistic One-Dimensional Self-Gravitating Systems
We consider the statistical mechanics of a general relativistic
one-dimensional self-gravitating system. The system consists of -particles
coupled to lineal gravity and can be considered as a model of
relativistically interacting sheets of uniform mass. The partition function and
one-particle distitrubion functions are computed to leading order in
where is the speed of light; as results for the
non-relativistic one-dimensional self-gravitating system are recovered. We find
that relativistic effects generally cause both position and momentum
distribution functions to become more sharply peaked, and that the temperature
of a relativistic gas is smaller than its non-relativistic counterpart at the
same fixed energy. We consider the large-N limit of our results and compare
this to the non-relativistic case.Comment: latex, 60 pages, 22 figure
Higher Order Stability of a Radiatively Induced 220 GeV Higgs Mass
The effective potential for radiatively broken electroweak symmetry in the
single Higgs doublet Standard Model is explored to four sequentially subleading
logarithm-summation levels (5-loops) in the dominant Higgs self-interaction
couplant . We augment these results with all contributing leading
logarithms in the remaining large but sub-dominant Standard Model couplants
(t-quark, QCD and gauge couplants) as well as next to
leading logarithm contributions from the largest of these, the t-quark and QCD
couplants. Order-by-order stability is demonstrated for earlier leading
logarithm predictions of an order 220 GeV Higgs boson mass in conjunction with
fivefold enhancement of the value for over that anticipated from
conventional spontaneous symmetry breaking.Comment: revtex, 6 pages. Analysis and text is expanded in revised versio
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