Quark masses and their hierarchies

Electroweak symmetry breaking is attributed to dynamical generation of quark masses. Quarksq (and leptonsl) are assumed to be produced by hypercolor confinement of preons at an intermediate scaleΛ _hc. Hierarchies observed in theq mass spectra can be explained by a BCS mechanism if the color interaction is enough asymptotically free and if residual ones emerging by the confinement are medium strong. The former assumption claims thatN≦4, whereN is the family number ofq andl. Dynamical equations to determineq masses and mixings are given, but they require knowledge on the physics atΛ _hc. A phenomenological approach is also made on the basis of anSU(7)×SU(7) chiral preon model withN=4. The mass ratiom _t/mb is related to (m _c/m _s)^ηB withη _B?1.1 andm _t'/mb' to (m _u/m _d)^ηA withη _A?1.4. In this scheme the fourth down quark is the heaviest (～ 110 GeV) and contributes dominantly toF ², whereF is the Fermi scale.     

On the time evolution of generator coordinates

Collective potential energy surfaces were determined in the mass region with 50<(N, Z)<82 by fitting experimental level spectra andB(E 2)-values on the basis of the generalized collective model of Gneuss and Greiner. While the nuclides withN=80 and withZ=52 are rather soft vibrators we find an abrupt transition to asymmetric rotators forN=78 and forZ=54 tending to more symmetric shapes further away from the closed shells. The results predict the position of levels not yet observed andB(E 2)-values.     

Hyperfine structure investigations in the4F9/2 atomic ground state of191Ir and193Ir

The5d ⁷6s^{2 4}F_9/2 atomic ground state of¹⁹¹Ir and¹⁹³Ir has been studied using the atomic-beam magnetic-resonance method. The results are:¹⁹³Ir:g _J(⁴F_9/2)=1.29694 (3)¹⁹¹Ir:Δv(⁴F_9/2; F=6?F=5)=659.26496 (12) MHzΔv( ⁴F_9/2; F=5?F=4)=189.44002 (09) MHzΔv( ⁴F_9/2; F=3?F=4)=84.05040 (80) MHzA=57.52148 (04) MHzB=471.20425 (57) MHzC=?0.020 (30) kHz¹⁹³Ir:Δv( ⁴F_9/2; F=6?F=5)=660.09043 (12) MHzΔv( ⁴F_9/2; F=5?F=4)=224.47848 (13) MHzΔv( ⁴F_9/2; F=?F=4)=33.53453 (89) MHzA=62.65556 (05) MHzB=426.23546 (64) MHzC=0.020 (30) kHz Using the magnetic dipole moments known by NMR-technique [1] we obtained for the electric quadrupole moments as calculated from the hyperfine interaction constantsA andB:Q(¹⁹¹Ir)=0.78 (20) barns,Q(¹⁹³Ir)=0.70 (18) barns (uncorrected for core polarization effects). A calculation of the hyperfine anomaly yields:₁₉₁ Δ ₁₉₃=?0.00023 (10). The ratio of theB factors which should be the same as for the quadrupole moments turned out to be:B(¹⁹¹Ir)/B(¹⁹³Ir)=Q(¹⁹¹Ir)/Q(¹⁹³Ir)=1.105502(3).     

Multiquark clusters in nuclei. distributions ofu- andd-quarks

Effects related to the possible admixture of multiquark (mainly 12q) clusters (bags) in nuclei are discussed. In particular the differencies in theu- andd-quark distributions inN≠Znuclei are considered. The quark distribution function is assumed to consist of two components: the nucleon component and the bag one (mainly the 12q-bag). The yields ofπ-mesons and nucleons into the backward hemisphere are governed mainly by the contribution of the bag component. It comes from the available data on theπ ⁺/π ^? andn/p ratios that thed-quarks in the bag component of nuclei withN>Z are “more soft” than theu-quarks in contrast to the situation in the nucleon component. The manifestation of the latter effect in theA-dependence of the ratio of structure functionsR=F _2A(x)/F _2D(x) is also discussed.     

The second EMC effect,semileptonic baryon decays and the chiral bag

TheU(1) anomaly gives a massiveη ₀ in the chiralSU(3) limit. We show in this limit how a chiral bag model givesboth theF andD amplitudes consistent with all baryon semileptonic decays,and the integral over the spin structure function measured by the EMC collaboration.     

Semileptonic decays of charmedD ± meson

Using the ACCMOR spectrometer equipped with a vertex telescope of high resolution silicon microstrip detectors 74 decays \(D^ + \to \bar K^{*0} (892)e^ + v_e \) (andcc.) withx _F <0.4 have been observed in 200 GeV π^? Be interactions. The cross-section forD ^± production, itsx _F -dependence in the central region and theD ^± lifetime have been measured.     

Formfactor effects in exclusiveD andB decays

Recent experimental results on the semileptonicD→K ^* transition seem to be in conflict with quark model expectations. Motivated by this finding we reinvestigate the predictions for exclusiveD andB decays in the relativistic quark model approach. Some of the invariant formfactors relevant for the transition matrix elementsD→K ^* andB→D ^* depend strongly on an explicit quarkmass-dependent integral over the meson wave functions. The dependence of decay rates and spectra in semi-leptonicD andB transitions on this integral is analysed and discussed in detail. Furthermore, we discuss how the predictions of the relativistic quark model for semi-leptonicD andB decays can be tested through measurements of the polarization of the produced vector mesonK ^* andD ^*, respectively. Some remarks on exclusive nonleptonic two-body decays of the heavy mesons are also presented. Finally the theoretical uncertainties for the determination of the K-M matrix element |V _ub | from exclusive semi-leptonic decays are discussed.     

Hydrogen maser atomic beam resonances

Au^? ions at anionic places are formed in gold doped crystals by a reducing treatment withF centers. The ultraviolet absorption consists of 4 bands, which are namedA, B, C, andD in analogy to the isoelectronic centers of the s² type, like Tl⁺. TheB band oszillator strength strongly increases with temperature in accordance with a phonon allowed transition. The ratio of the dipole strength of theC band to that of theA band as a function of the relative position of theB band is compared with Suganos prediction. Zero phonon lines are found at helium temperatures for theA band in NaCl (2,985 Å), KCl (3,068 Å), and KBr (3,145 Å) and for theC band in KCl (2,329 Å). In KCl the Huang-Rhys factor isg=3.4 for theA band. The vibronic structure comes from the relatively large radius 6s ² state of the negative ion. Uniaxial stress splits the zero phonon line. The results definitely agree with the stress splitting behaviour of a degenerateΓ ₁→Γ ₄ transition. Inversion symmetry of the center is confirmed by the absence of a linear Stark effect.     

Isotope shift and hyperfine structure of the transition5d6s 2 2 D 3/2-5d6s6p 4 F 3/2 of Lu175 and Lu176

Using a tunable single mode dye laser the isotope shift of the 573.7 nm-line between the isotopes Lu¹⁷⁵ and Lu¹⁷⁶ has been determined to be IS(176?175, 573.7 nm)=?394(5) MHz yielding a change of mean square nuclear radii ofδ〈r ²〉=0.022(5) fm². In addition from our measurements the following values of the hyperfine splitting constantsA andB could be deduced Lu¹⁷⁶ 5d6s6p ⁴ F _3/2:A=?651.4(0.3) MHz,B=2,494(4) MHz 5d6s ^{2 2} D _3/2:A=138.0(0.3) MHz,B=2,131(3) MHz Lu¹⁷⁵ 5d6s6p ⁴ F _3/2:A=?924.7(0.5) MHz,B=1,767(4) MHz.     

Optical absorption spectrum and crystal field of erbium aluminum garnet (ErAlG)

The optical absorption spectrum of Erbium Aluminum Garnet (ErAlG) has been measured between 12000 cm^?1 and 26000 cm^?1. The crystal field splitting of the terms⁴I_15/2,⁴I_9/2,⁴F_9/2,⁴S_3/2,²H_11/2,⁴F_7/2,⁴F_5/2,⁴F_3/2,²H_9/2 and⁴G_11/2 was determined from the spectra and has been analysed in terms of the usual parametrization scheme. Nine crystal field parametersA _l ^m 〈r ^l〉≡B _l ^m which are necessary to describe the crystal field with the symmetryD ₂ at the site of the rare earth ion, were fitted to the experimental data. The values are (in cm^?1):B ₂ ⁰=+160B ₄ ⁰=?160B ₆ ⁰=+30B ₆ ⁶=+80B ₂ ²=?100B ₄ ²=+140B ₂ ⁶=?40B ₄ ⁴=?1800B ₆ ⁴=?700 This result is compared with those obtained from similar analysis of other garnets.     

Non-supersymmetric vacua and the D-flatness condition

Some N = 1 gauge theories, including SQED and N_F = 1 SQCD, have the property that, for arbitrary superpotentials, all stationary points of the potential V = F + D are D-flat. For others, stationary points of V are complex gauge transformations of D-flat configurations. As an implication, the technique to parametrize the moduli space of supersymmetric vacua in terms of a set of basic holomorphic G invariants can be extended to non-supersymmetric vacua. A similar situation is found in non-gauge theories with a compact global symmetry group.     

Investigation of hyperfine structure and isotope shift of the 605.5 nm-line of Lu176 by laser spectroscopy

Using a tunable single mode dye laser the hyperfine structure of the transition 5d6s ^{2 2} D _5/2 — 5d6s6p ⁴ F _5/2 has been investigated for the Lu-isotopes Lu¹⁷⁵ and Lu¹⁷⁶. From our measurements the following values for the hyperfine constantsA andB could be deduced Lu¹⁷⁶ 5d6s6p ⁴ F _5/2:A=698.4 (0.4) MHz,B=1,564 (10) MHz 5d6s ^{2 2} D _5/2:A=104.1 (0.3) MHz.B=2,631 (6) MHz Lu¹⁷⁵ 5d6s6p ⁴ F ^5/2:A=987.2(0.4) MHz,B=1,117(6) MHz. The isotope shift between the line centers has been determined to be IS(176-175, 605.5 nm)=?420(10) MHz.     

Exclusive non-leptonic decays ofD-,D s - andB-mesons

Recent experimental results onD-,D _s - andB-decays are interpreted on the basis of the valence quark model. For nonleptonic decays generally good results are obtained using factorization with little direct annihilation. Final state interaction causes corrections, however: small bare amplitudes can be fed by stronger amplitudes through channel mixing. This effect can simulate or enhance weak annihilation processes in particular if high lying resonances contribute. A comparison of \(D^0 \to \bar K^0 \phi \) withD _s →?π decays will clarify this issue. The effective QCD coefficients obtained in the analysis are discussed and used to estimate the contribution of two-body decays to the total widths. The result reflects already the lifetime differences betweenD ⁰ andD ⁺ mesons. Predictions for numerousB-decay branching rations allow for further tests and for a determination of so far unknown decay constants. A first bound on |V _ub | from nonleptonic decays is found from the experimental limit on \(\bar B^0 \to \pi ^ + \pi ^ - \) .     

Hyperfine structure and nuclear moments of99Ru and101Ru

The atomic-beam magnetic-resonance method in combination with the triple resonance technique has been used to determine the nuclear magnetic dipole moments of⁹⁹Ru and¹⁰¹Ru. The moments are deduced fromrf transition measurements in the⁵F₅ and⁵F₄ states at magnetic fields between 770 and 2400 Oe. In order to reduce the part of the uncertainty of the moments which arises from the uncertainty of the hyperfine structure constants more precise values of the constants than those available up to now were determined from low field measurements. After making corrections for hyperfine and Zeeman interactions with neighbouring atomic states we obtain the following values for the magnetic dipole moments:μ ₉₉=?0.6381 (51)μ _N andμ ₁₀₁=?0.7152 (60)μ _N (uncorrected for diamagnetic shielding). The results of the present work combined with the results of an earlier hyperfine structure investigation in the⁵F multiplet are analysed with respect to the effective-operator formalism. From this analysis we obtain the following values for the electric quadrupole moments:Q ₉₉=0.076 (7) b andQ ₁₀₁=0.44 (4) b (uncorrected for Sternheimer shielding or antishielding).     

Chiral SU(4) × SU(4) breaking: masses and decay constants of charmed hadrons

The (4, 4*) ⊕ (4*, 4) model of broken chiral SU (4) × SU (4) symmetry has been used to calculate the third-order coupling constants involving charmed and ordinary pseudoscalar mesons. These coupling constants are exploited to derive some interesting new relations among the masses and decay constants of these charmed particles. Using the known masses and decay constants as inputs, we exploit these relations to predict:F _D = −1·41F _π ,F _F = −1·13F _π ,F _D/F_F = 1·25,m(D _s) = 1·43 GeV,m(F _s) = 1·39 GeV andm(K _s) = 1·02 GeV.     

Can presentF 2 andR=σ L /σ T data unravel power corrections?

We analyse the QCD non-singlet leading order prediction ofR=σ _L /σ _L using the results of the EMCF ₂ fits to proton, deuterium and iron data and we examine in detail its compatibility withR from SLAC. Least squares fits to combined EMC and SLACF ₂ andR proton data are carried out at leading order in the non-singlet case. Incompatibilities have been confirmed which, in spite of present uncertainties, require the consideration of power corrections.     

Group theoretical aspects ofU B(6) ⊗U F(20) symmetry limits of IBFM related to theU B(5) andO B(6) limits of IBM

TheU ^B(6)⊗U ^F(20) Bose-Fermi dynamical symmetry of interacting boson-fermion model arises when the odd nucleon occupies single particle orbits withj=1/2, 3/2, 5/2, and 7/2. The subgroup structures ofU ^B(6)⊗U ^F(20) related to theU ^B(5) andO ^B(6) limits of sdIBM (U ^B(6)) are analysed. Broadly speaking,U ^B(6)⊗U ^F(20) admitsU ^BF(5)⊗U _s ^F (4), Spin^BF(5)⊗U _k ^F (5) andU ^BF(5)⊗U _s ^F (2) limits withU ^B(5) core and Spin^BF(6),O ^BF(5)⊗U _s ^F (4), Spin^BF(6)⊗U _k ^F (5) andO ^BF(6)⊗U _s ^F (2) limits withO ^B(6) core respectively. For each of these seven symmetry limits, group chains, quantum numbers labelling the basis states, generators and Casimir operators for the various subgroups and energy formulas are given. Recoupling coefficients (reduced Wigner coefficients) for constructing wavefunctions of low-lying states are tabulated and these will allow (together with sdIBMU ^B(5) andO ^B(6) limit results) one to calculateB(E2)’s,B(M1)’s, one and two nucleon transfer strengths etc. in the seven symmetry limits. Experimental examples for theU ^B(6)⊗U ^F(20) symmetry limits are briefly discussed.     

The Stark effect in the 6snf Rydberg series of barium

The Stark effect has been studied in the odd-parity 6snf^1,3F₃ Rydberg series of barium with high-resolution laser-atomic-beam spectroscopy. Scalar and tensor polarizabilities have been measured of 6snf¹F₃ levels with n=11–30 and of 6snf³F₃ levels withn = 12 ? 40. The contributions of the adjacent even-parity Rydberg levels to these polarizabilities have been calculated as far as data are available. This results in important additional information on the only partly known 6sng^1,3G₄ series and confirms the perturbation of these series atn = 24 by a 5d7dJ= 4 level. A tentative three-channel quantum-defect-theory analysis of the^1,3G₄ series has been performed. It is shown that reported level energies of the 6snd^1,3D₂ series are systematically 0.14 cm^?1 too high.     

Precision measurement of the hyperfine structure of Lu175 with the atomic beam magnetic resonance method

The hyperfine structure separations of both doublet states² D _3/2 and² D _5/2 of the ground state configuration 6s ² 5d of Lu¹⁷⁵ have been remeasured with high precision using the atomic beam magnetic resonance method. Magnetic dipole transitions between Zeeman components of the hfs levels were induced applying Ramsey's technique of separated oscillatory fields whenever the field dependence of the resonances was small enough. The hfs intervals at zero field and hfs interaction constants were derived from the measurements. The constants were then corrected for hfs perturbations between the two levels of the doublet. Configuration interaction has been taken into account for the calculation of the dipole matrix elements. The corrected hfs constants are:J=3/2:A=194.332921 (300) MHzB=1511.396 267 (320) MHzC=?70 (19) HzJ=5/2:A=146.776 472 (138) MHzB=1860.656132 (840) MHzC=913 (162) HzD=?16 (24) Hz A quadrupole hfs anomaly between Lu¹⁷⁵ and Lu^176m was not found when comparing the following two ratios: Lu¹⁷⁵:B(5/2)/B(3/2)=1.2310850 (16) Lu^176m :B(5/2)/B(3/2)=1.2310818 (30). So far we have not succeeded in computing an octopole moment from the twoC-factors for the terms² D _3/2,5/2 because the influence of higher configurations could not sufficiently be considered.     

Etude De La Conductivite Electrique Des Ferrites Oxyfluores A Structure Spinelle

An investigation of the electrical conductivity of some oxyfluoride spinels of formula Zn_x²⁺Fe_1?x³⁺[M²⁺ Fe³⁺]O_4?xF_x (M = Fe, Co, Ni) and Fe³⁺[N_x²⁺Fe²⁺Fe_1?x³⁺]O_4?xF_x (N = Fe, Ni) shows that the conduction depends on the composition of the B sites: the activation energy increases, the conductivity and the Fe₃O₄ transition temperature decrease as the substitution rate of Fe³⁺ by N²⁺ in the B sites increases. The authors conclude to a hopping mechanism between the B cations; the anionic sublattice and the cationic A sublattice do not participate in the conduction.