On the role of the higgs mechanism in present electroweak precision tests

Based on the observablesM _W, Γ _l ,s _W ^?2 (M _Z ² ), we evaluate the parameters Δx, Δy and ε at one-loop level within an electroweak massive vector-boson theory, which does not employ the Higgs mechanism. The theoretical results are consistent with the experimental ones on Δx, Δy, ε. The theoretical prediction for Δy coincides with the standard-model one (apart from numerically irrelevant terms which vanish forM _H→∞). Nonrenormalizability only affects Δx and ε, which differ from the standard-model results by the replacement logM _H→log Λ for a heavy Higgs mass,M _H (where Λ denotes an effective UV cut-off).     

Oscillator strength of electron-type color centers in KCl single crystals irradiated with electrons and protons

The absorption spectra of KCl single crystals irradiated with electrons and protons at energies of 15 and 100 keV and a particle flux ranging from 5×10¹² to 10¹⁵ cm^?2 are investigated. The absorption bands attributed to simple (F, F _a, K) and complex (M, R ₂, R ₄, N) color centers are identified in the spectra. The correlation dependences of the absorption coefficients for M, R ₂, and R ₄ centers on the absorption coefficient of F centers and the correlation dependences of the absorption coefficients for R ₂ and R ₄ centers on the absorption coefficient of M centers are established. The oscillator strengths are calculated for M, R ₂, and R ₄ color centers.     

Bounds on the masses of neutral generation-changing gauge bosons

The existence of several generations of quarks and leptons suggests the possibility of a gauge symmetry connecting the different generations. The neutral gauge bosons of such a scheme would mediate rare processes such as K_L⁰→μ^±, K⁺→π⁺e^?π⁺, μN→eN and would contribute to ΔM(K_S⁰?K_L⁰). We study these and other processes within a simple theoretical framework and derive bounds involving the masses and coupling constants of the generation-changing gauge bosons and various generation-mixing angles. The lower bounds for the relevant masses lie in the 10–100 TeV region. Various remarks concerning the relevance of these bounds to currently popular theoretical ideas and to future experiments are presented.     

Study of ^{201} Tl\xrightarrow{\varepsilon }^{201} Hg decay properties

The intensities of the transitions to the ground-state and the first excited level of ²⁰¹Hg in ²⁰¹Tl decay and the values of the constant log ft are estimated on the basis of an analysis of the relative intensities of the mercury M ₄ N _6,7 N _6,7 Auger electron line induced by ? capture and the mercury conversion O ₃ line caused by the 1.56-keV nuclear transition.     

Crossover behavior of anisotropic cubic system with ionic anisotropy

Crossover behavior of anisotropic cubic N-component spin system with ionic anisotropies of different magnitude is studied in terms of the renormalization-group (RG) approach in momentum space. As a fundamental case, we choose a system with two kinds of strength of ionic anisotropies (i.e. m²₁ for the M-component spin and m²₂ for the other (N–M)-one), which has a bicritical point. We discuss the critical behavior and crossover behavior between the M- component system and the N-component system on the critical exponents [i.e., coefficient functions appearing in the RG equation of γS for the spin field S, γS² for the S²-field and γδS² for the δS² (≡[(N-M)S²₂-MS²₂]/N)-field] and on the temperature-dependent crossover exponent γeff.     

Electric conduction properties of M@C2n endohedral metallofullerenes (M=La, Y)

The electrical conduction properties of powder samples of M@C_2n endohedral metallofullerenes (M=La, Y) isolated from soot by extraction with N,N-dimethylformamide and by sublimation were studied. It was established that the conductivity of sublimated samples exceeded that of the extracted ones by four orders of magnitude and was as high as 0.2–0.5 Ω^?1 cm^?1 at room temperature.     

3-Methyl and N-Methyl-substitution in heptanuclear complexes effects multistability investigated by Mössbauer spectroscopy

The precursors [Fe^(III)(^N???R???L)Cl] (^N???R???LH₂ = N,N ^′ -bis(2’-hydroxy-3’- methyl-benzyliden)-1,7-diamino-4-R-4-azaheptane, R = H, methyl(Me)) are high-spin (S?=?5/2) complexes. The Lewis-acidic precursors are combined with Lewis-Base-bridging-units [M(CN) _x ] ^y??? (M = Fe^(II), Ru^(II), Co^(III)) to form heptanuclear star-shaped [M{CN–Fe^(III)(^N???R???L)} _x ]Cl _y molecular switches. The starshaped compounds are high-spin systems at room temperature. On cooling to 20 K some of the compounds exhibit multistability, i.e. several iron(III) centers within a molecule switch the spin state as shown by Mössbauer spectroscopy.     

Gain studies on a uranine-damc dye mixture laser under nitrogen laser pumping

The radiative and Forster type of energy transfer processes in a dye mixture laser of 7-diethylamino-4-methyl coumarin (donor) and fluorescein disodium salt (acceptor) under nitrogen laser pumping were investigated. The Forster transfer rate calculated from the absorption and emission spectra of acceptor and donor is 1.3 × 10¹¹ liter mole^?1sec^?1. The gain of acceptor at 550 nm was measured for acceptor concentrations N_A from 10^?3M to 3 × 10^?3M for a fixed ratio F = 1 of donor to acceptor concentrations at different pump powers. The results agreed with the rate equation model proposed for the dye mixture laser. The radiative rate constant calculated from these results is 3.1 × 10¹⁰ liter mole^?1sec^?1. Numerical simulation of the rate equations showed that the acceptor reaches peak emission with a time lag of 3 ns with respect to the donor peak emission for F = 0.998, N_A = 10^?5M. This time lag decreases with increasing N_A and becomes zero for N_A = 10^?1M, F = 0.048.     

<Emphasis Type="Italic">M</Emphasis>α and <Emphasis Type="Italic">M</Emphasis>β X-ray emission spectra of Au atoms upon photoionization of <Emphasis Type="Italic">L</Emphasis> subshells

The structure and relative intensity of the Mα and Mβ X-ray fluorescence spectra of Au atoms are studied experimentally at the energies of absorbed photons both below and above the ionization thresholds of L subshells (Kα_{1, 2} radiation of Cr, Cu, and Mo). The M ₅ N and M ₄ N high-energy satellites are separated from the total spectral profiles and their relative intensities are determined. A model of the M emission is proposed that allows one to take into account the main channels of vacancy transfer from L to M subshells, which are responsible for the generation of double vacancy (M _{4, 5} N and M _{4, 5} O) and triple vacancy (M _{4, 5} N ², M _{4, 5} NO, and M _{4, 5} O ²) states. Comparison of the experimental relative intensities of separated M ₅ N and M ₄ N satellites excited by the Mo Kα_{1, 2} radiation with the calculated results indicates the correctness of the model used. The partial and total M emission cross sections of Au in the absorbed photon energy range of 5–30 keV are calculated. It is found that, in the photon energy region above the ionization threshold of the L ₃ subshell, our results noticeably differ from the data calculated by other authors. Possible reasons for these discrepancies are discussed.     

Penetrative ferroconvection via internal heating in a saturated porous layer with constant heat flux at the lower boundary

A model for penetrative ferroconvection via internal heat generation in a ferrofluid saturated porous layer is explored. The Brinkman-Lapwood extended Darcy equation with fluid viscosity different from effective viscosity is used to describe the flow in the porous medium. The lower boundary of the porous layer is assumed to be rigid- paramagnetic and insulated to temperature perturbations, while at upper stress-free boundary a general convective-radiative exchange condition on perturbed temperature is imposed. The resulting eigenvalue problem is solved numerically using the Galerkin method. It is found that increasing in the dimensionless heat source strength N_s, magnetic number M₁ Darcy number Da and the non-linearity of magnetization parameter M₃ is to hasten, while increase in the ratio of viscosities Λ, Biot number Bi and magnetic susceptibility χ is to delay the onset of ferroconvection. Further, increase in Bi, Da⁻¹ and N_s and decrease in Λ, M₁ and M₃ is to diminish the dimension of convection cells.     

Classical theory of a space-time sheet

By embedding the space-time V₄ in a higher-dimensional space M_N we can formulate a theory of gravity in which the true dynamical variables are the coordinates η^a(x) (a = 1,2,…, N) of V₄ with respect to M_N. Before constrained by the variational principle, which gives the equations of the four-surface V₄, all the coordinates η^a are independent. This enables the canonical formulation of the theory (without additional constraints except for the initial and boundary conditions on η^a and ones due to the reparametrization invariance) which is presented here. When expressed in terms of the metric tensor g_μ$\text{v}$ of the space-time four-surface V₄ the theory reduces to the Einstein general relativity.     

The missing mass squared dependence of the average charged particle multiplicity in the reaction K+p → KoX++ from 5–16 GeV/c

The average charged particle multiplicity, 〈n_ch(M_X²)〉, in the reaction K⁺p→K^oX⁺⁺ is studied as a function of the mass squared, M_X², of the recoil system X and also as a function of the K^o transverse momentum, p_T, at incident momenta of 5.0, 8.2 and 16.0 GeV/c. The complete data samples yield distributions which are not independent of c.m. energy squared, s, They exhibit a linear dependence on log (M_X²_X/M_o²)[M_o²=1 GeV²] with a change in slope occurring for M_X²≈s/2, and do not agree with the corresponding distributions of 〈n_ch〉 as a function of s for K⁺ p inelastic scattering. Sub-samples of the data for which K^o production via beam fragmentation, central production and target fragmentation are expected to be the dominant mechanisms show that, within error, the distribution of 〈n_ch(M_X²)〉 versus M_X² is independent of incident momentum for each sub-sample separately. In particular in the beam fragmentation region the 〈n_ch(M_X²)〉 versus M_X² distribution agrees rather well with that of 〈n_ch〉 versus s for inelastic K⁺p interactions. The latter result agrees with recent results on the reactions pp → pX and π^?p → pX in the NAL energy range. Evidence is presented for the presence of different production mechanisms in these separate regions.     

Proton decay

The lifetimes and branching ratios of the proton and bound neutron are calculated in the SO(10) grand unified theory by taking into account the form factor effect (by making use of SU(6) symmetric wave functions for the nucleons and mesons) and the generation mixing, based on the assumption that the ΔB = ? 1 decay interaction is generated by the exchange of superheavy leptoquark gauge bosons, D (X and Y) and E (X' and Y'). In our approach there is a free parameter M_D/M_E, which should be determined by experiment. The branching ratio of the inclusive decay of an I = 0 nucleus into neutrinos and anything is found to be most dependent on the ratio M_D/M_E. The nucleon lifetime is τ_N = [M_D (GeV)/5 × 10¹⁴]⁴ × (0.0015,2.5,4.6) × (1_?0.4⁺²) × 10³⁰ year, for M_D/M_E = (10,1,0.1). Only the cases in which M_DapM_E are found to be possible for Λ_ms[? 0.26 GeV and τ_N ? 5 × 10³⁰ year if there is not a fourth generation of light fermions, technicolored particles nor supersymmetric particles.     

Relative intensities in x-ray photoelectron spectra. Part VI. The spectra of He(I), He(II), Y Mζ and Zr Mζ

The 2s- and 2p-electron photoionization cross-sections at photon energies up to 190 eV have been calculated, using the RPAE method for averaged configurations of the C, N, O and Ne atoms. The RPAE method ensures a more accurate relation between the cross-sections, 2s/2p, than that obtained using the Hartree—Fock method. Within the framework of the Gelius—Siegbahn model, but with the use of theoretical atomic cross-sections, we have calculated the photoionization cross-sections for He(I), He(II), Y Mζ, Zr Mζ for CH₄, C₂H₆, C₃H₈, C₂H₄, C₂H₂, NH₃, H₂O, CN^?, N₂, CO, CO₂, N₂O and NO₂^? molecules. For CO, N₂, CO₂, N₂O and H₂O molecules, a comparison is made between the theoretical and experimental cross-sections for hν < 60 eV. The calculated absolute and relative values of the molecular-orbital cross-sections are in reasonable agreement with experiment, especially at hν ? 40 eV. The calculations correctly reproduce the change in intensities under the transition He(I) → He(II). We have shown that our calculations have a significant advantage over those performed using the PW and OPW approximations. It is shown for NO, N₂, CO, H₂O, CH₄, NH₃ and N₂O molecules that the total photoionization cross-section calculated taking into account the real structure of the molecular orbitals is in better agreement with the experimental photoabsorption cross-section than is the sum of the cross-sections for the atoms in a molecule.     

Triplet spin excitons in organic charge transfer complexes

Electron paramagnetic resonance (EPR) spectra of single crystals of the 1 : 1 charge transfer (CT) complex of N, N'-dimethyldihydrophenazine (M₂P) and of tetracyanoquinodimethane (TCNQ) provide the first case of thermally activated, with ΔE_p = 0.60 ± 0.06 eV, triplet spin excitons observed in an organic CT solid. The narrow EPR lines and resolved fine structure splittings indicate mobile triplets based on adjacent M₂P⁺TCNQ^- ion radicals above a largely neutral ground state.     

Preparation of Sm3+–Eu3+ coactivating red-emitting phosphors and improvement of their luminescent properties by charge compensation

By charge compensating, a series of red-emitting phosphors Ca_0.54Sr_0.16Ca_0.54Sr_0.31Eu_0.08Sm_0.02(MoO₄)_0.6(WO₄)_0.4 were synthesized. Two approaches to charge compensation were used: (a) 2Ca²⁺/Sr²⁺→Eu ³⁺/Sm³⁺+M ⁺, where M⁺ is a monovalent cation like Li⁺, Na⁺ or K⁺; (b) Ca²⁺/Sr²⁺→Eu ³⁺/Sm³⁺+N ^?, where N⁺ is a monovalent anion like F^?, Cl^?, Br^?, or I^?. One red LED was made by combining the phosphor and 390–405 nm emitting LED chip under 20 mA forward-bias current, the color purity, chromaticity coordinates and the luminous intensity of which were 99.5%, x=0.66, y=0.33, 5600 mcd, respectively.     

Percolation on the square lattice in aL×M geometry

A study of the site percolation model on the square lattice in aL×M geometry at critically is presented. ForL?M one observes the growth of numerous percolation colation clusters in theL-direction in contrast to the absence of percolation in theM-direction. Consequently, relevant properties of these clusters such us for example the average number of clusters (N _CL ), the cluster length distribution (P(l,L), withl=cluster length in theM direction) and average cluster length (l _CL ), are studied by means of the Monte Carlo technique and analyzed on the basis of finite-size scaling arguments. The following behavior is found:N _CL ?(3/8) (L/M)^?δ, with δ=1; andl _CL ?2.0L. Also the distributionP(l, L) is of the exponential-exponential type and their characteristic exponents are evaluated.     

“Forbidden” soft-X-ray absorption edges in the alkali halides

Transitions from s core levels to the conduction-band edge and to excitons derivable therefrom are forbidden by symmetry in the alkali halides. Excepting K spectra, all indications from the literature seem to be that L₁, M₁, N₁, O₁ spectra are in fact unobservable. By untangling some data available for NaBr in the region where the Na⁺L₁ and Br^?M_{4 5} spectra overlap, we suggest that “forbidden” spectra may indeed by observable, and more detailed scans in certain regions of photon energy might be useful. The importance of excitons in X-ray spectra is further elucidated and earlier conclusions are confirmed.     

Extremes of N Vicious Walkers for Large N: Application to the Directed Polymer and KPZ Interfaces

We compute the joint probability density function (jpdf) P _N (M,?? _M ) of the maximum M and its position ?? _M for N non-intersecting Brownian excursions, on the unit time interval, in the large N limit. For N????, this jpdf is peaked around $M = \sqrt{2N}$ and ?? _M =1/2, while the typical fluctuations behave for large N like $M - \sqrt{2N} \propto s N^{-1/6}$ and ?? _M ?1/2??wN ^?1/3 where s and w are correlated random variables. One obtains an explicit expression of the limiting jpdf P(s,w) in terms of the Tracy-Widom distribution for the Gaussian Orthogonal Ensemble (GOE) of Random Matrix Theory and a psi-function for the Hastings-McLeod solution to the Painlevé II equation. Our result yields, up to a rescaling of the random variables s and w, an expression for the jpdf of the maximum and its position for the Airy₂ process minus a parabola. This latter describes the fluctuations in many different physical systems belonging to the Kardar-Parisi-Zhang (KPZ) universality class in 1+1 dimensions. In particular, the marginal probability density function (pdf) P(w) yields, up to a model dependent length scale, the distribution of the endpoint of the directed polymer in a random medium with one free end, at zero temperature. In the large w limit one shows the asymptotic behavior logP(w)???w ³/12.