545 research outputs found
Fermion Masses and Coupling Unification in E6. Life in the Desert
We present an Grand Unified model with a realistic pattern of fermion
masses. All standard model fermions are unified in three fundamental 27-plets
(i.e. supersymmetry is not invoked), which involve in addition right handed
neutrinos and three families of vector like heavy quarks and leptons. The
lightest of those can lie in the low TeV range, being accessible to future
collider experiments. Due to the high symmetry, the masses and mixings of all
fermions are closely related. The new heavy fermions play a crucial role for
the quark and lepton mass matrices and the bilarge neutrino oscillations. In
all channels generation mixing and violation arise from a single
antisymmetric matrix. The breaking proceeds via an intermediate energy
region with SU(3)_L\tm SU(3)_R\tm SU(3)_C gauge symmetry and a discrete
left-right symmetry. This breaking pattern leads in a straightforward way to
the unification of the three gauge coupling constants at high scales, providing
for a long proton lifetime. The model also provides for the unification of the
top, bottom and tau Yukawa couplings and for new interesting relations in
flavor and generation space.Comment: RevTex4, three ps figures, some correction
THE MODEL CHARACTERISTICS OF JUMP ACTIONS STRUCTURE OF HIGH PERFORMANCE FEMALE VOLLEYBALL PLAYERS
The purpose of this study was to develop generalized and individual models of the jump actions of skilled female volleyball players. The main prerequisite for the development of the jump actions models were the results of our earlier studies of factor structure of jump actions of 10 sportswomen of the Polish volleyball team "Gedania" (Premier League) in the preparatory and competitive periods of the annual cycle of preparation. The athletes age was 22.0 +- 2.9 years, the sports experience - 8.1 +- 3.1 years, body height - 181.9 +- 8.4 years and body weight - 72.8 +- 10.8 kg. Mathematical and statistical processing of the data (the definition of M ± SD and significant differences between the samples) was performed using a standard computer program "STATISTICA 7,0". Based on the analysis of the factor structure of 20 jump actions of skilled women volleyball players determined to within 5 of the most informative indexes and their tentative values recommended for the formation of a generalized model of this structure. Comparison of individual models of jump actions of skilled women volleyball players with their generalized models in different periods of preparation can be used for the rational choice of means and methods for the increasing of the training process efficiency
A Predictive Minimal Model for Neutrino Masses and Mixings
A model is considered in which the scale of the heavy singlet neutrinos is a
few orders of magnitude below the grand unification scale and where
right-handed vector bosons play still a negligible role. In a basis with
diagonal up-quark and Dirac-neutrino mass matrices it is assumed that the heavy
neutrino mass matrix has only zero elements in its diagonal, in analogy to the
light neutrino mass matrix in the Zee model. Connecting then the remaining
matrix elements with the small parameter describing the hierarchy of quark
masses and mixings and by assuming commutativity of the charged lepton with the
down-quark mass matrix, the calculation of all neutrino properties can be
performed in terms of the two mass differences relevant for atmospheric and
solar neutrino oscillations. CP-violation is directly related to CP-violation
in the quark sector.Comment: revtex, 9 pages, two references added, to be published in Phys. Rev.
D presented at Neutrino' 2000, Sudbury, Canad
Leading twist moments of the neutron structure function F2n
We perform a global analysis of neutron F2n structure function data, obtained
by combining proton and deuteron measurements over a large range of kinematics.
From these data the lowest moments (n <= 10) of the leading twist neutron F2n
structure function are extracted. Particular attention is paid to nuclear
effects in the deuteron, which become increasingly important for the higher
moments. Our results for the nonsinglet, isovector (p - n) combination of the
leading twist moments are used to test recent lattice simulations. We also
determine the lowest few moments of the higher twist contributions, and find
these to be approximately isospin independent, suggesting the possible
dominance of ud correlations over uu and dd in the nucleon.Comment: 34 pages, 13 figures. Minor changes. Version to appear in NP
Non-local anomaly of the axial-vector current for bound states
We demonstrate that the amplitude does not vanish in the limit of zero quark masses. This
represents a new kind of violation of the classical equation of motion for the
axial current and should be interpreted as the axial anomaly for bound states.
The anomaly emerges in spite of the fact that the one loop integrals are
ultraviolet-finite as guaranteed by the presence of the bound-state wave
function. As a result, the amplitude behaves like in the limit of
a large momentum of the current. This is to be compared with the amplitude
which remains
finite in the limit .
The observed effect leads to the modification of the classical equation of
motion of the axial-vector current in terms of the non-local operator and can
be formulated as a non-local axial anomaly for bound states.Comment: revtex, 4 pages, numerical value for in Eq. (19) is
corrected, Eqs. (22) and (23) are modified. New references added. Results
remain unchange
Comments on Diquarks, Strong Binding and a Large Hidden QCD Scale
We present arguments regarding diquarks possible role in low-energy hadron
phenomenology that escaped theorists' attention so far. Good diquarks, i.e. the
states of two quarks, are argued to have a two-component structure with
one of the components peaking at distances several times shorter than a typical
hadron size (a short-range core). This can play a role in solving two old
puzzles of the 't Hooft 1/N expansion: strong quark mass dependence of the
vacuum energy density and strong violations of the Okubo-Zweig-Iizuka (OZI)
rule in the quark-antiquark channels. In both cases empiric data defy
't Hooft's 1/N suppression. If good diquarks play a role at an intermediate
energy scale they ruin 't Hoofts planarity because of their mixed-flavor
composition. This new scale associated with the good diquarks may be related to
a numerically large scale discovered in [V. Novikov, M. Shifman, A. Vainshtein
and V. Zakharov, Nucl. Phys. B 191, 301 (1981)] in a number of phenomena mostly
related to vacuum quantum numbers and glueball channels. If SU(3) of bona fide QCD is replaced by SU(2), diquarks become
well-defined gauge invariant objects. Moreover, there is an exact symmetry
relating them to pions. In this limit predictions regarding good diquarks are
iron-clad. If passage from SU(2) to SU(3) does not
lead to dramatic disturbances, these predictions remain qualitatively valid in
bona fide QCD.Comment: 18 pages, 3 figures; journal version, minor change
Remote sensing: Physical principles, sensors and products, and the LANDSAT
Techniques of data acquisition by remote sensing are introduced in this teaching aid. The properties of the elements involved (radiant energy, topograph, atmospheric attenuation, surfaces, and sensors) are covered. Radiometers, photography, scanners, and radar are described as well as their products. Aspects of the LANDSAT system examined include the characteristics of the satellite and its orbit, the multispectral band scanner, and the return beam vidicon. Pixels (picture elements), pattern registration, and the characteristics, reception, and processing of LANDSAT imagery are also considered
Hydro-physical processes at the plunge point: an analysis using satellite and in situ data
The plunge point is the main mixing point between river and epilimnetic reservoir water. Plunge point monitoring is essential for understanding the behavior of density currents and their implications for reservoir. The use of satellite imagery products from different sensors (Landsat TM band 6 thermal signatures and visible channels) for the characterization of the river-reservoir transition zone is presented in this study. It is demonstrated the feasibility of using Landsat TM band imagery to discern the subsurface river plumes and the plunge point. The spatial variability of the plunge point evident in the hydrologic data illustrates the advantages of synoptic satellite measurements over in situ point measurements alone to detect the river-reservoir transition zone. During the dry season, when the river-reservoir water temperature differences vanish and the river circulation is characterized by interflow-overflow, the river water inserts into the upper layers of the reservoir, affecting water quality. The results indicate a good agreement between hydrologic and satellite data and that the joint use of thermal and visible channel data for the operational monitoring of a plunge point is feasible. The deduced information about the density current from this study could potentially be assimilated into numerical models and hence be of significant interest for environmental and climatological research
Experimental cross sections of Ho 165 (α,n) Tm 168 and Er 166 (α,n) Yb 169 for optical potential studies relevant for the astrophysical γ process
Background: Optical potentials are crucial ingredients for the prediction of nuclear reaction rates needed in simulations of the astrophysical γ process. Associated uncertainties are particularly large for reactions involving α particles. This includes (γ,α) reactions which are of special importance in the γ process. Purpose: The measurement of (α,n) reactions allows for an optimization of currently used α-nucleus potentials. The reactions Ho165(α,n) and Er166(α,n) probe the optical model in a mass region where γ process calculations exhibit an underproduction of p nuclei which is not yet understood. Method: To investigate the energy-dependent cross sections of the reactions Ho165(α,n) and Er166(α,n) close to the reaction threshold, self-supporting metallic foils were irradiated with α particles using the FN tandem Van de Graaff accelerator at the University of Notre Dame. The induced activity was determined afterwards by monitoring the specific β-decay channels. Results: Hauser-Feshbach predictions with a widely used global α potential describe the data well at energies where the cross sections are almost exclusively sensitive to the α widths. Increasing discrepancies appear towards the reaction threshold at lower energy. Conclusions: The tested global α potential is suitable at energies above 14 MeV, while a modification seems necessary close to the reaction threshold. Since the γ and neutron widths show non-negligible impact on the predictions, complementary data are required to judge whether or not the discrepancies found can be solely assigned to the α width. © 2014 American Physical Society.Peer reviewedFinal Accepted Versio
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