134 research outputs found

    Quality Measurement of Hay Stored by Large Hay Packaging Systems

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    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

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    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

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    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 Yi(0)→∞Y_i(0)\to\infty. However the solutions are attracted to such points rather weakly. For this reason when all Yi(0)∌1Y_i(0)\sim 1 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 bb--quark and τ\tau--lepton Yukawa coupling unification at the scale MXM_{X} is also discussed.Comment: 32 pages, 8 figures included, LaTeX 2

    A Search for Instantons at HERA

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    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

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    Nowadays in the MSSM the moderate values of tan⁥ÎČ\tan\beta 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 mh∌125m_h\sim 125 GeV at values of tan⁥ÎČ≄1.9\tan\beta\ge 1.9. In the investigated model the lightest Higgs boson mass does not exceed 130.5±3.5130.5\pm 3.5 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

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    The simplest extension of the MSSM that does not contradict LEP II experimental bound on the lightest Higgs boson mass at tan⁥ÎČ∌1\tan\beta\sim 1 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 bb-quark and τ\tau-lepton Yukawa coupling unification at the Grand Unification scale MXM_X 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

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    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

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    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 ηâ€Č\eta'

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    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 ηâ€Č\eta' 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 ηâ€Č\eta', in double-pomeron exchange pppp 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 MX<8M_X<8 GeV reported by UA8

    Primordial Neutrinos, Cosmological Perturbations in Interacting Dark-Energy Model: CMB and LSS

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    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 ∑mÎœ<0.87eV\sum m_{\nu} < 0.87 eV 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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