Top-quark-mass enhancement in a seesaw-type quark mass matrix

We investigate the implications of a seesawtype mass matrix, i.e.,M _f?m _LM _F ^?1 m _R, for quarks and leptonsf under the assumption that the matricesm _L andm _R are common to all flavors (up-/down- and quark-/lepton-sectors) and the matricesM _F characterizing the heavy fermion sectors have the form [(unit matrix)+b _f (a democratic matrix)] whereb _f is a flavor parameter. We find that by adjusting the complex parameterb _f, the model can provide thatm _t?m _b while at the same time keepingm _u??m _d without assuming any parameter with hierarchically different values betweenM _U andM _D. The model with three adjustable parameters under the ??maximal?? top-quark-mass enhancement can give reasonable values of five quark-mass ratios and four KM matrix parameters.     

In-beam spectroscopy of231Pa

Information on energy levels and onE 2 andM 1 matrix elements in²³¹Pa has been obtained using conversion-electron and gamma-ray spectroscopy following the²³²Th(p, 2n)²³¹Pa reaction and Coulomb excitation of the radioactive target²³¹Pa by⁴He and³²S ions. The results are analyzed in the framework of the rotational model, applied to the rotational band built on the 1/2^?[530] Nilsson state whose 3/2^? member forms the ground state of this nucleus. The deviations of the level energies from the rigid-rotor values can be described by Coriolis couplings. The analysis of the Coulomb-excitation process shows that a constant set of rotational parameters Q₀, g_R, g_K, andb can fairly well account for the measured line intensities.     

On the octupole excitation in236U

Measurements of theK,L _I,L _II andM _I conversion lines of the 687.7 keV transition in²³⁶U are evaluated within the electron penetration formalism. The spin-parity assignment of the octupole bandhead is found to be 1^? in accordance with reaction data, and an assignment of 2^? to the 687.7 keV state is ruled out. The penetration matrix element ∥η∥ has the value of 13.5 for theK-shell and increases slightly for higher main shells. An estimate of the anomalous amplitudes is compared with values reported for transitions in the odd even actinide nuclei. Furthermore electron conversion data for the 1^?→2⁺ and 1^?→4⁺ transitions are given. Radioactivity²³⁶U from²³⁵U(n,e ^?); measured: conversion electron decay; deduced: conversion coefficients fromK, L andM shells; evaluated: dynamic matrix elements.     

UV and VUV spectroscopic study of Na0.4Y0.6F2.2 crystals doped with rare-earth ions

The short-wavelength transmission spectra of Na_0.4 R _0.6F_2.2 crystals with R = Y, Yb, or Lu have been investigated. For these crystals, the VUV transmission cutoffs are 78750, 58820, and 75200 cm^?1, respectively. The 4f ⁿ–4f ^n?15d absorption and excitation spectra of Na_0.4Y_0.6F_2.2 crystals activated with Ce³⁺, Pr³⁺, Nd³⁺, Er³⁺, Tm³⁺, and Yb³⁺ ions have been analyzed in the range 30000–80000 cm^?1. The energy positions of the lowest levels of the 4f ^n?15d configurations of these ions in the fluorite crystal matrix Na_0.4Y_0.6F_2.2 are determined. The absorption band in the spectral range 60600–70000 cm^?1 in Na_0.4(Y, Yb)_0.6F_2.2 crystals is due to the charge transfer from F^? to Yb³⁺. It is shown that the environmental symmetry of Ce³⁺ ions in Na_0.4R_0.6F_2.2 (R = Y, Yb, Lu) crystals is almost identical.     

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.     

Majorana masses,photon gas heating and cosmological constraints on neutrinos

Non-vanishing Majorana masses generally lead to flavor-changing neutral currents in the neutrino sector. It is shown that when both right- and left-handed neutrinos have non-vanishing Majorana masses (M_R≠0 and M_L≠0), flavor-changing neutral currents could be as large as flavor-diagonal ones. However, when only right-handed neutrinos have non-vanishing Majorana masses (M_R≠0 but M_L=0), flavor-changing neutral currents are small. If M_R?D (Dirac masses), they are of $\text{O}\text{((}\text{D}\text{M}{}_{\mathrm{<mtext>R</mtext>}}\text{)}{}^2\text{)}$. If M_R?D, they are $\text{?(}\text{m}{}_{\mathrm{<mtext>L</mtext>}}\text{m}{}_{\mathrm{<mtext>H</mtext>}}\text{)}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$, where m_L and m_H are masses of light and heavy neutrinos appearing in a flavor-changing process.By using these results we examine cosmological implications of non-vanishing flavor-changing neutral currents. Heavy neutrinos can decay into three light neutrinos at an appreciable rate by exchanging a Z-boson. It is demonstrated that owing to this decay mode, heavy neutrinos of mass larger than 70 keV but less than 2m_e give rise to no contradiction with the standard big bang cosmology in the most general case.We also show that if there exist heavy neutrinos of mass m_H2m_e, their decay at an early era of the universe induces photon gas heating, which alters Cowsik and McClelland's constraint on light neutrino masses to Σm_L < k · 100 eV with the sum running over all Majorana eigenstates. Here the constant k, representing the heating effect of the photon gas, is restricted by the deuterium abundance of the present universe. For instance, Σm_L < 240 eV for m_H ～ 25 MeV and the present baryon density = 3.4 × 10^?31 g · cm^?3.     

Propagation of Hermite-cosh-Gaussian laser beams in n-InSb

The propagation of Hermite-cosh-Gaussian (HChG) laser beams in n-InSb are investigated for 0, 1 and 2 mode indices. The field distribution in the medium is expressed in terms of beam-width parameter f and decentred parameter b. The differential equations for f-parameter are established by parabolic wave equation approach under paraxial approximation. Analytical solutions are obtained under the condition R_n < R_d, where, R_n is the self-focusing length and R_d is the diffraction length. The behaviour of f-parameter with the dimensionless distance of propagation η for various b values is examined by numerical estimates. The results are presented graphically.     

The effectiveg s factor for the odd proton153Sm nucleus determined by the internal conversion processes

TheK/L ₃,L ₁/L ₃,L ₁/L ₂ andL ₂/L ₃ conversion ratios for the 103 keV transition in¹⁵³Sm were measured by means of a high-resolution π√2 electron spectrometer. The values of theM1 conversion penetration parameter λ=5.0 _?0.7 ^+0.6 and the mixing ratio δ²=0.144±0.006 are deduced. By comparing the experimental penetration parameter with the value obtained from Nilsson model calculations the effective spin gyromagnetic ratio is found to be $$g_s^{eff} = \left( {3.7\begin{array}{*{20}c} { + 0.4} \\ { - 0.5} \\ \end{array} } \right)\mu _n .$$      

Calculation of high-order rotational centrifugal-distortion matrix elements for a Hund's case (a) basis set

The derivation of explicit expressions for the Hund's case (a) matrix elements of R^2k is discussed, where R is the mechanical rotational angular momentum operator of the molecule. A recursion relation is developed that permits matrix elements of R^2k to be expressed in terms of those of R^2(k?1), thus affording a straightforward means of calculating the case (a) matrix elements of rotational centrifugal-distortion constants D_v, H_v, L_v, M_v, etc., to an arbitrarily high order. The explicit matrix elements of L_v are listed.     

Gravitational charges,f-gravity and hadron masses

Two types of fundamental gravitational charges are suggested by quantization of the angular momentum (i.e. J=n?, wheren is an integer or half integer) occurring in the uncharged and charged Kerr metrics. These charges turn out to bee/√a ande/a, wheree is the unit electric charge anda the fine structure constant. The use of strong (f) gravity leads to corresponding fundamental massesM ₁(f) ～2.2×10^?24 g andM ₂(f)～2.3×10^?23 g. It is postulated that the hadrons are composed of these fundamental entities (christened oms here). Thus mesons arediomic particles and baryons aretriomic particles. This has a close resemblance to the quark model but here we deal with gravitational charges. The charges constituting hadrons are bound together by strong (f) gravity which is super strong compared to nuclear forces. Various hadron masses are obtained as the vibrational excitations of these composite units. The above model is capable of accounting for quantum numbers such as spin, baryon number, strangeness and isospin.     

Resurrecting no-scale supergravity phenomenology

In the context of phenomenological models in which the soft supersymmetry-breaking parameters of the MSSM become universal at some unification scale, M _in, above the GUT scale, M _GUT, it is possible that all the scalar mass parameters m ₀, the trilinear couplings A ₀ and the bilinear Higgs coupling B ₀ vanish simultaneously, as in no-scale supergravity. Using these no-scale inputs in a renormalisation-group analysis of the minimal supersymmetric SU(5) GUT model, we pay careful attention to the matching of parameters at the GUT scale. We delineate the region of M _in, m _1/2 and tan?β where the resurrection of no-scale supergravity is possible, taking due account of the relevant phenomenological constraints such as electroweak symmetry breaking, m _h ,b→s γ, the neutralino cold dark matter density Ω _χ h ² and g _μ ?2. No-scale supergravity survives in an L-shaped strip of parameter space, with one side having m _1/2?200 GeV, the second (orthogonal) side having M _in?5×10¹⁶ GeV. Depending on the relative signs and magnitudes of the GUT superpotential couplings, these may be connected to form a triangle whose third side is a hypotenuse at larger M _in, m _1/2 and tan?β, whose presence and location depend on the GUT superpotential parameters. We compare the prospects for detecting sparticles at the LHC in no-scale supergravity with those in the CMSSM and the NUHM.     

Constraining new physics with B→K ∗ μ + μ − in the early LHC era

We investigate the observables available in the angular distribution of B→K ^? μ ⁺ μ ^? to identify those suitable for measurements in the first few years of LHC data taking. There are three observables that may be extracted by counting signal events as a function of one or two decay angles and correspond to large features of the full angular distribution in the Standard Model: A _FB, F _L, and S ₅. Two of these are well known in the experimental community; however, we show that measuring S ₅ adds complementary sensitivity to physics beyond the Standard model. Like A _FB, it features a zero-crossing point with reduced hadronic uncertainties at leading order and in the large recoil limit. Due to the high gradient of S ₅ at this point, we find it would be possible for LHCb to measure it to high precision. Current experimental model independent constraints on parameter space are presented and predictions made for the values of the A _FB and S ₅ zero-crossing points. The relative impact of early LHCb measurements of A _FB, F _L, and S ₅ is assessed. These issues are explored with a new model of the decay that can be used with standard simulation tools such as EvtGen.     

Investigations of the spin-Hamiltonian parameters and defect structures for Gd ions in YMO4 (M=V, P, As) crystals

A 56×56 energy matrix containing the ground multiplet ⁸S_7/2 and the excited multiplets ⁶L_7/2 (where L=P, D, F, G, H, I) for 4f⁷ ion Gd³⁺ at a tetragonal crystal field and under an external magnetic field is constructed. By diagonalizing the energy matrix, the spin-Hamiltonian parameters (g factors g_‖, g_⊥ and zero-field splittings b₂⁰, b₄⁰, b₄⁴, b₆⁰, b₆⁴) for Gd³⁺ ion at the tetragonal Y³⁺ site of YMO₄ (M=V, P, As) crystals are calculated. The calculated results are in reasonable agreement with the experimental values. The defect structures of Gd³⁺ centers in YMO₄ crystals are estimated from the calculation. The results are discussed.     

Description of the nuclear surface by moments

The parameters proposed by W. D. Myers to describe the radial shape dependence of the nuclear surface are shown to be as useful as they are natural. For spherical nuclei, the central radiusC, the charge radiusR, the quadratic radiusQ are redefined, and it is shown how they are interrelated by Myers' surface widthb, flair γ₃, crookedness γ₄, and the higher shape parameter γ₅. All these quantities are calculated for some special charge distribution functions. (For symmetric distributions, possessing a symmetry center atC, the odd surface momentsb ³γ₃ andb ⁵γ₅ vanish.) The connection of the surface moments Г_μ =b ^μ γ _μ with the volume momentsF _k that have been extracted by K. W. Ford and J. G. Wills from muonic atoms, is indicated.     

F L structure function and heavy quark contributions

In this paper we obtain the heavy-quark contribution to the longitudinal structure functions F _L (x, Q ²). Since F _L structure functions contains rather large heavy flavor contributions in the small x region, we need to use the massive operator matrix elements, which contribute to the heavy flavor Wilson coefficients in unpolarized deeply inelastic scattering in the region Q ²?>?>?m ². The method of QCD analysis, based on the Jacobi polynomials method, is also described. Our results for longitudinal structure function are in good agreement with the available experimental data.     

Renormalization scheme dependence of electroweak radiative corrections

We compare two renormalization schemes of the electroweak standard model: the on-shell scheme withe, M _W ,M _Z ,M _H , and the fermion masses {m _f } as free parameters, and an intermediate scheme where theW boson self energy is renormalized atq ²=0 instead ofq ²=M _W ². TheM _W ?M _Z interdependence, and the differentiale ⁺ e ^?→μ ⁺ μ ^? cross section including polarized beams are calculated in both schemes to one-loop order. We find striking differences between the forward-backward asymmetries and the polarization asymmetries near theZ resonance after inclusion of weak and QED corrections.     

Electroweak parameters from a high statistics neutrino nucleon scattering experiment

The final results from the WA 1/2 neutrino experiment in the 1984 CERN 160 GeV narrow band beam are presented. The ratiosR _ν and \(R_{\bar v} \) of neutral to charged current interaction rates of neutrinos and antineutrinos in iron are measured to beR _ν=0.3072±0.0033 and \(R_{\bar v} \) =0.382±0.016. A value of the electroweak parameter sin² θ _w = 1 ?m _W ² /m _Z ² is extracted fromR _ν. The result is sin² θ _w =0.228+0.013(m _c ?1.5)±0.0003 (theor.) wherem _c is the mass of the charmed quark in GeV form _t =60 GeV,M _H =100 GeV, ρ=1. CombiningR _ν and \(R_{\bar v} \) one obtains a value for ρ=0.991+0.023(m _c ?1.5)±0.020(exp.). Alternatively,R _ν and \(R_{\bar v} \) yield a precise value of the ratio of intermediate vector boson massesm _W /m _Z =0.880?0.007(m _c ?1.5)±0.002(exp.)±0.002(theor.). Comparison of these results with those from direct measurements of the vector boson masses are presented. In a model-independent analysis the left- and right-handed neutral current coupling constants,g _L ² andg _R ² , are determined.     

Dynamical mass generation

We investigate the possibility of calculating the fermion and the gauge-boson masses within an electroweakSU(2)_L ×U(1)_Y gauge-invariant model without the Higgs fields. Instead of the whole Higgs sector we introduce one Abelian vector boson C with massM renormalizably interacting with leptons and quarks of chiralities L and R with a strengthh. An interplay of all interactions which contribute to the fermion masses results in the fermion mass formulam _f= =M exp[87²/(3y(f _L)y(f _R)h ²)], wherey(f _L,R) are the C hypercharges, and y(f_L). y(f _R) < 0. The intermediate-boson massesm _w andm _z are expressed in terms of the fermion masses via sum rules.Invited talk presented at the International Conference Selected Topics in Quantum Field Theory and Mathematical Physics, Bechyn, Czechoslovakia, June 23–27, 1986.     

Precession of angular momentum vector in a slowly rotating Kerr metric

Specializing Penrose and Floyd's resultF _ab;c =F _[ab;c] to the Kerr metric, we explicitly construct the skew symmetric tensorF _ab and Carter's quadratic integral of geodesic motion.F _ab is then shown to be closely related to the orbital angular momentum encountered in Newtonian mechanics. Furthermore, F_ab can be decomposed additively intoL _ab andM _ab , whereL _ab has the character of angular momentum, andM _ab exists only for a nonzero rotation parameter,a, of the Kerr metric. It turns out that the equation of precession = _a ^b L _b has a nontrivial solution only for the case of a slowly rotating Kerr metric valid to first order in rotation parameter. In this case, Carter's integral can be interpreted as the squared length of the precessing angular momentum vectorL _a =L _a ^b P _b . The equation of precession is solved, and a vector ^a describing angular velocity of precession is derived.     

High multipolarity nuclear excitations in the continuum

The strength distributions of particle-hole isoscalar transitions with high multipolarities are considered in the framework of the independent particle model using the Woods-Saxon potential. It is shown that for the multipole operatorsj _L (qr)Y _LM withL?A ^1/3 andq?p _F the distributions are peaked at the relatively low energy for allL, and their widths decrease asL ^?1/2. In contrast to that, for the surface external fields (?U/?r)Y _LM the centroid excitation energy is proportional toL ² and the distribution widths increase asL ^4/3. The conclusion is drawn that the p-h excitations might be responsible for the structures in the excitation function observed in heavy ion collisions in the energy region up to ≈2ε _F .