134 research outputs found
Quality Measurement of Hay Stored by Large Hay Packaging Systems
The purpose of this study was to determine to what extent large hay package storage retained the initial forage quality by measurement of seven quality parameters over an extended period. The Hesston 60 and Haybuster 1800 were used as examples of hay packaging systems for study
Infrared Fixed Point Structure in Minimal Supersymmetric Standard Model with Baryon and Lepton Number Violation
We study in detail the renomalization group evolution of Yukawa couplings and
soft supersymmetry breaking trilinear couplings in the minimal supersymmetric
standard model with baryon and lepton number violation. We obtain the exact
solutions of these equations in a closed form, and then depict the infrared
fixed point structure of the third generation Yukawa couplings and the highest
generation baryon and lepton number violating couplings. Approximate analytical
solutions for these Yukawa couplings and baryon and lepton number violating
couplings, and the soft supersymmetry breaking couplings are obtained in terms
of their initial values at the unification scale. We then numerically study the
infrared fixed surfaces of the model, and illustrate the approach to the fixed
points.Comment: 16 pages REVTeX, figures embedded as epsfigs, replaced with version
to appear in Physical Review D, minor typographical errors eliminated and
references reordered, figures correcte
Infrared quasi-fixed solutions in the NMSSM
The considerable part of the parameter space in the MSSM corresponding to the
infrared quasi fixed point scenario is almost excluded by LEP II bounds on the
lightest Higgs boson mass. In the NMSSM the mass of the lightest Higgs boson
reaches its maximum value in the strong Yukawa coupling limit when Yukawa
couplings are essentially larger than gauge ones at the Grand Unification
scale. In this limit the solutions of the renormalisation group equations are
attracted to the infrared and Hill type effective fixed lines or surfaces in
the Yukawa coupling parameter space. They are concentrated in the vicinity of
quasi fixed points for . However the solutions are attracted
to such points rather weakly. For this reason when all the
solutions of the renormalisation group equations are gathered near a line in
the Hill type effective surface. In the paper the approximate solutions for the
NMSSM Yukawa couplings are given. The possibility of --quark and
--lepton Yukawa coupling unification at the scale is also
discussed.Comment: 32 pages, 8 figures included, LaTeX 2
A Search for Instantons at HERA
A search for QCD instanton (I) induced events in deep-inelastic scattering
(DIS) at HERA is presented in the kinematic range of low x and low Q^2. After
cutting into three characteristic variables for I-induced events yielding a
maximum suppression of standard DIS background to the 0.1% level while still
preserving 10% of the I-induced events, 549 data events are found while
363^{+22}_{-26} (CDM) and 435^{+36}_{-22} (MEPS) standard DIS events are
expected. More events than expected by the standard DIS Monte Carlo models are
found in the data. However, the systematic uncertainty between the two
different models is of the order of the expected signal, so that a discovery of
instantons can not be claimed. An outlook is given on the prospect to search
for QCD instanton events using a discriminant based on range searching in the
kinematical region Q^2\gtrsim100\GeV^2 where the I-theory makes safer
predictions and the QCD Monte Carlos are expected to better describe the
inclusive data.Comment: Invited talk given at the Ringberg Workshop on HERA Physics on June
19th, 2001 on behalf of the H1 collaboratio
Higgs bosons in the simplest SUSY models
Nowadays in the MSSM the moderate values of are almost excluded
by LEP II lower bound on the lightest Higgs boson mass. In the Next-to-Minimal
Supersymmetric Standard Model the theoretical upper bound on it increases and
reaches maximal value in the strong Yukawa coupling limit when all solutions of
renormalization group equations are concentrated near the quasi-fixed point.
For calculation of Higgs boson spectrum the perturbation theory method can be
applied. We investigate the particle spectrum in the framework of the modified
NMSSM which leads to the self-consistent solution in the strong Yukawa coupling
limit. This model allows one to get GeV at values of
. In the investigated model the lightest Higgs boson mass
does not exceed GeV. The upper bound on the lightest CP-even
Higgs boson mass in more complicated supersymmetric models is also discussed.Comment: 27 pages, 5 figures included, LaTeX 2e. Plenary talk at the
Conference of RAS Nuclear Physics Department 2000 in ITEP, Moscow, Russia; to
appear in Phys. Atom. Nuc
Quasi-fixed point scenario in the modified NMSSM
The simplest extension of the MSSM that does not contradict LEP II
experimental bound on the lightest Higgs boson mass at is the
modified Next-to-Minimal Supersymmetric Standard Model (MNSSM). We investigate
the renormalization of Yukawa couplings and soft SUSY breaking terms in this
model. The possibility of -quark and -lepton Yukawa coupling
unification at the Grand Unification scale is studied. The particle
spectrum is analysed in the vicinity of the quasi-fixed point where the
solutions of renormalization group equations are concentrated at the
electroweak scale.Comment: 19 pages, 3 figures, LaTeX2
The high-energy hadron spin-flip amplitude at small momentum transfer and new AN data from RHIC
In the case of elastic high-energy hadron-hadron scattering, the impact of
the large-distance contributions on the behaviour of the slopes of the
spin-non-flip and of the spin-flip amplitudes is analysed. It is shown that the
long tail of the hadronic potential in impact parameter space leads to a value
of the slope of the reduced spin-flip amplitude larger than that of the
spin-non-flip amplitude. This effect is taken into account in the calculation
of the analysing power in proton-nucleus reactions at high energies. It is
shown that the preliminary measurement of AN obtained by the E950 Collaboration
indeed favour a spin-flip-amplitude with a large slope. Predictions for AN at
pL = 250 GeV/c are given.Comment: 16 pages, 5 figures, a few typos fixed in v.
Determining neutrino absorption spectra at Ultra-High Energies
A very efficient method to measure the flux of Ultra-high energy (UHE)
neutrinos is through the detection of radio waves which are emitted by the
particle shower in the lunar regolith. The highest acceptance is reached for
radio waves in the frequency band of 100-200 MHz which can be measured with
modern radio telescopes. In this work we investigate the sensitivity of this
detection method to structures in the UHE neutrino spectrum caused by their
absorption on the low-energy relic anti-neutrino background through the Z-boson
resonance. The position of the absorption peak is sensitive to the neutrino
mass and the redshift of the source. A new generation of low-frequency digital
radio telescopes will provide excellent detection capabilities for measuring
these radio pulses, thus making our consideration here very timely.Comment: 7 figures, submitted to JCAP revision: References updated and minor
changes in tex
Semiclassical Double-Pomeron Production of Glueballs and
A semiclassical theory of high energy scattering based on interrupted
tunneling (instantons) or QCD sphaleron production has been recently developed
to describe the growing hadronic cross section and properties of the soft
Pomeron. In this work we address double-pomeron processes in this framework for
the first time. We specifically derive the cross section for central production
of parity even and odd clusters, scalar and pseudoscalar glueballs, and
in parton-parton scattering at high energy. We show that the specific
dependence of the production cross section on all its kinematical variables
compares favorably with the UA8 data on inclusive cluster production, as well
as the WA102 data on exclusive central production of scalar glueball and
, in double-pomeron exchange scattering. The magnitude of the cross
section and its dependece on kinematic variables is correct, explaining in
particular a large deviation from the Pomeron factorization at cluster masses
in the range GeV reported by UA8
Primordial Neutrinos, Cosmological Perturbations in Interacting Dark-Energy Model: CMB and LSS
We present cosmological perturbation theory in neutrinos probe interacting
dark-energy models, and calculate cosmic microwave background anisotropies and
matter power spectrum. In these models, the evolution of the mass of neutrinos
is determined by the quintessence scalar field, which is responsible for the
cosmic acceleration today. We consider several types of scalar field potentials
and put constraints on the coupling parameter between neutrinos and dark
energy. Assuming the flatness of the universe, the constraint we can derive
from the current observation is at the 95 % confidence
level for the sum over three species of neutrinos. We also discuss on the
stability issue of the our model and on the impact of the scattering term in
Boltzmann equation from the mass-varying neutrinos.Comment: 26 pages Revtex, 11 figures, Add new contents and reference
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