Innere Konversion der 161 keV- und 223 keV-Übergänge in133Cs

Using a Ge(Li)-Si (Li)-spectrometer the 161 keV and 223 keV transitions of¹³³Cs were investigated. TheK-conversion coefficients were deduced to beα _K =0.205±0.007 andK-conversion coefficients were deduced to beα _K =0.0743±0.0043, respectively. TheK/L ratio for the 161 keV transition is 4.72±0.37. From theK-conversion coefficients were deduced to beα _K -values,M1 penetration factors ofλ=8.6±3.4 andλ=7.8 _?2.8 ^3.0 were deduced which are inconsistent with known data from angular correlation experiments (λ=40±10 andλ=90±13). The penetration factor fromK/L-measurement for the 161 keV-transition isλ=52±19. A theoretical reinvestigation of the formulas used in the literature appears recommendable. Furthermore, theK/L ratio of the 1770 keV transition of²⁰⁷Pb was determined experimentally to be 5.52±0.54.     

The higgs boson mass from precision electroweak data

We present a new global fit to precision electroweak data, including new low- and high-energy data and analyzing the radiative corrections arising from the minimal symmetry breaking sectors of the Standard Model (SM) and its supersymmetric extension (MSSM). It is shown that present data favor a Higgs mass ofO(M _z):M _H=76 _?50 ⁺¹⁵² GeV. We confront our analysis with (meta) stability and perturbative bounds on the SM Higgs mass, and the theoretical upper bound on the MSSM Higgs mass. Present data do not discriminate significantly between the SM and MSSM Higgs mass ranges. We comment in passing on the sensitivity of the Higgs mass determination to the values ofα(M _z) andα _s(M _z).     

Constraints on masses of supersymmetric scalar partners of quarks by parity violating nuclear transitions

A pair of supersymmetric scalar partners of each quark is, in general, not degenerate in mass. Experimental measurements of parity violating nuclear transitions impose constraints on their masses when they are not degenerate. Specifically, if the mixing of the scalar partners of opposite chiralities is small and the current mass of the gluinos is small, the quantity (ΔM_s²?tM_s,t²)M_s,t²ln(M_s,tmλ_G²) should be in the range of (100 GeV)^?2 or less, where M_s,t² are the squared masses of a pair of the scalar partners of u or d flavor, ΔM_s?t² is their splitting, and m_λG is the current mass of the gluinos.     

Lattice (Φ 4)4 effective potential giving spontaneous symmetry breaking and the role of the Higgs mass

We present a critical reappraisal of the available results on the broken phase ofλ(Φ ⁴)₄ theory, as obtained from rigorous formal analyses and from lattice calculations. All the existing evidence is compatible with Spontaneous Symmetry Breaking but dictates a trivially free shifted field that becomes controlled by a quadratic hamiltonian in the continuum limit. As recently pointed out, this implies that the simple one-loop effective potential should become effectively exact. Moreover, the usual naive assumption that the Higgs mass-squaredm _h ² is proportional to its “renormalized” self-couplingλ _R is not valid outside perturbation theory: the appropriate continuum limit hasm _h finite and vanishingλ _R . A Monte Carlo lattice computation of theλ(Φ ⁴)₄ effective potential, both in the single-component and in theO(2)-symmetric cases, is shown to agree very well with the one-loop prediction. Moreover, its perturbative leading-log improvement (based on the concept ofλ _R ) fails to reproduce the Monte Carlo data. These results, while supporting in a new fashion the peculiar “triviality” of theλ(Φ ⁴)₄ theory, also imply that, outside perturbation theory, the magnitude of the Higgs mass does not give a measure of the observable interactions in the scalar sector of the standard model.     

A simple example of a singular perturbation expansion

For the Hamiltonian?=?? _x ² -αδ(x)+λx ² the bound-(λ>0) and resonance(λ<0) states are discussed. The perturbation expansion of the ground-state? ₀(λ) in powers ofλ is divergent for allλ. The nature of the singularity atλ=0 is investigated and it turns out, that the perturbation series is asymptotic and therefore useful even forλ<0.     

An evidence for a possible stable dibaryon

A search for stableH-dibaryon ofI=0,Y=0,J ^P =0⁺ was undertaken in negative pion-, neutron-,¹²C-nucleus- and proton-propane interactions at 4.0, 7.0, 50.4 and 10 GeV/c, respectively, using 55 cm and 2 m propane bubble chambers. This technique permite one to examine the whole range of possibleH-mass value. In the range ofM _H >2M _Λ=2231.2 MeV/c² an enhancement ofM _ΛΛ=(2365.3±9.6) MeV/c², Γ _ΛΛ =(47.2±15.1) MeV/c² with production cross section σ=(24.2±7.0) μb per carbon nucleus was found. The mass rangeM _Σ?p<M _H <2M _Λ was explored via the search for a weak decay modeH→Σ^?+p. AV ⁰-particle was found pointing to a two-prong interaction and satisfying the kinematics of the above two-body decay mode with a high confidence level. The possibility of imitation of the observed event by background processes was investigated for a series of two-step strong reactions and weak decays. We succeeded to show the significance of theH-production hypothesis on a deuteron-mass nuclear fluctuon via thepd→HpK ⁺ K ⁰ reaction. The mass of the event treated as aH→Σ^?+p weak decay appeared to be (2173.94±1.32) MeV/c², its life-time being 0.668·10^?10 s. Both are in agreement with predictions of the MIT Bag Model for the so-calledH-dihyperon. The formally determined production cross section of theH in proton-propane interactions at 10 GeV/c is estimated to be 40 nb. Perhaps, this event can be considered as a first evidence for a six-quark bound state-H-dihyperon. An independent way for the search for theH-particle, based on a specific conversion processHN→YYN, peculiar to its intranuclear strong interactions was proposed and tried. For this purpose all events with two Λ-hyperons and identified protons were tested for the hypothesesH _p →ΛΛp at three fixed masses:M _H =1880.00, 2173.94 MeV/c² and the ΛΛ invariant mass for the event in question. The kinematics of this reaction fits successfully only one event and only atM _H =2173.94 MeV/c². It seems worthy of note that the final state ΛΛ invariant massM _ΛΛ=2344 MeV/c² is rather close to the observed peak at 2365 MeV/c². It is shown that the intranuclear conversion processes Ξ^? p→ΛΛ and Ξ⁰ n→ΛΛ fail to imitate the observed event. The ΛΛp invariant mass of this event equal to 3363 MeV/c² is out of a 3568 MeV/c² peak region of the ΛΛp invariant mass spectrum observed earlier. TheH conversion cross section exceeds the production one. Thus, we consider this event as providing a new evidence for the stableH-dibaryon ofM _H =(2173.94±1.32) MeV/c².     

Another calculation of the Higgs mass and the top mass from the principles of H. B. Nielsen: m H ≅ 163GeV for M t ≅ 190GeV

We calculate the Higgs mass and the top mass starting from the principle that there are two, essentially degenerate minima in the Higgs effective potential; the second is at about the Planck energy scale M _P = 1.2 × 10¹⁹ GeV. Thus the parameter of the quartic self-coupling λ _h vanishes, as does β _λH at M _P. The new element is the addition of a quantum interaction term which couples the square of the Higgs field to the square of a pseudoscalar field, in the domain of the energy scale between about 10¹⁴ GeV and M _P. We modify β _λH at one loop. The pseudoscalar field which is introduced may be the field which is responsible for a spontaneous breakdown of discrete symmetry — for CP noninvariance at an energy scale of (10¹⁵–10¹⁶) GeV. The result is then a closer value for m _H ? 163 GeV for the top pole-mass M _t ? 190 GeV; both values are now close to the electroweak scale parameter $\langle {\phi _H}\rangle /\sqrt 2 = 175{\text{ GeV}}$ . In terms of dimensionless running coupling parameters, which determine the masses near to the electroweak scale, we get $\sqrt {{\lambda _H}} \cong 0.06$ and $gt/\sqrt 2 \cong 0.72$ , values that are close to each other and close to unity.     

Abhängigkeit der effektiven Masse von der Ladungsträgerkonzentration im Bi2Se3

High quality Bi₂Se₃ crystals with 50 to 65 At% Se have been produced. As a consequence of a Se-doping, the carrier density varies between 3 · 10¹⁹ to 8 · 10¹⁷ cm^?3. Based on optical reflection and transmission measurements in the near infrared the dispersion of the refractive indexn(λ) has been calculated. The plasma resonance frequencyΝ _Pl lies within the energy region from 0.05 to about 0.1 eV. Fromn(λ) andΝ _Pl the effective mass of the electrons in Bi₂Se₃ has been evaluated. Near the band edge a value ofm _⊥c ^*+0.02m ₀ has been found. It depends on the orientation of the crystals and on the carrier concentration. The results of the electrical and optical investigations give reason to assume an isotropic mean free time of the electrons. The “six-valley-model” ofHashimoto for the energy-surfaces in Bi₂Se₃, is confirmed.     

Verification of the laws of luminescence of solids for manganese complexes of benzyl-trimethylammonium and 2-chloropyridinium

A formula at low temperature for the function G($\text{1}\text{λ}$) = I_λλ⁶ has been derived in terms of configuration curve theory and checked on luminescence spectra near 77 K. The vibrational quantum in the excited state has been calculated from the decrease of G($\text{1}\text{λ}{}_{\mathrm{M}}$), where λ_M is the wavelength of the maxima of G at low temperature, as a function of temperature.     

The Nambu,Jona-Lasinio model and low energy effective meson Lagrangians

Using standard techniques, the Nambu-Jona-Lasinio Lagrangian with its chirally invariant four-fermion couplings is transformed into a bosonized form which includes scalar, pseudo-scalar, vector and axial-vector fields. Then, after eliminating the scalar and axialvector fields in an appropriate way, we obtain the Lagrangian given by Bando et al. based on the “hidden” local symmetry approach, except that in the present approach the free parametera of their model is now uniquely given by a=(1? M _V ² /M _A ² )^?1 in terms of the vector and axial-vector meson massesM _V andM _A. The value ofa=2, which led them to remarkable phenomenological successes is therefore directly connected with the Weinberg mass relation M_A=√2M_V in this model. The formal equivalence between the hidden symmetry approach and the massive Yang-Mills scheme is clearly demonstrated in the present approach, which derives an effective meson theory starting from a Lagrangian at the underlying quark level.     

A grand unified theory based onSU(n, 1)-minimal supergravity

We discuss a grand unified theory in the framework ofSU(n, 1) minimal supergravity with the Planck mass as the only input mass scale.M _W ≈m _3/2 is fixed by radiative corrections to be naturally ?M _P1. Due to the particular form of explicit soft supersymmetry breaking a light singlet can be used to obtain naturally light Higgs doublets and for a new mechanism for radiativeSU (2)×U(1) breaking. The low energy particle spectrum is very restricted withm _3/2≈10⁴ GeV.     

Bound on the Higgs boson mass with no zero-charge behaviour in a magnetic field

The upper boundm<280 GeV/c² on the Higgs boson mass is obtained by considering the requirement that the electroweak theory must be consistent in a magnetic fieldH. The restriction emerges naturally by studying the effective potential in a magnetic field as a function of mass, and the values ofm when there is no zero-charge, in the fieldsH～H ₀=M _w ² /e are obtained.     

The twistM λ,T=0 giant modes in spherical nuclei

The theory of twisting nuclear vibrations developed by Holzwarth and Eckart to elucidate the nature of the 2^? giant mode is extended to high-multipole, spin-independentM λ,T=0 resonances. Within the framework of the distorted Fermi-surface model the parameters of inertia and stiffness against multipolarity for the nuclear incompressible Fermi-drop are derived. The energies and probabilities of the twistingM λ,T=0 modes calculated in fact without adjustable constants readE(M λ)=?ω _F \(\left[ {\frac{{(2\lambda + 3)(\lambda - 1)}}{5}} \right]^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-0em} 2}} \) andB(M λ) = γ_λ Z² A ^(2λ-4)/3 μ² fm^(2λ-2)respectively. The comparison with data for the 2^? resonance and predictions for higher multipoles are presented.     

Fermion mass hierarchy based onN=8 supergravity

A possible mechanism is proposed to realize fermion mass hierarchy based on the superunification model of Ellis et al. In addition to the usual fermion (F)—Higgs (B) coupling, “non-renormalizable” interactions such as(1/(M _p ) ⁿ )(F) ² (B) ⁿ⁺¹ are introduced. It is assumed that three kinds of Higgs scalars respectively develop v.e.v. of orderM _P ,M _X andM _W , corresponding to the symmetry breaking pattern ofSU(8)→SU(5)→SU(3)×SU(3)×U(1)→SU(3)×U(1). As a result, fermions acquire their masses of orderM _w ,M _W (M _X /M _P) andM _W (M _X /M _P )². An example of the model is presented which shows nice feature of hierarchical mass patterns.     

A transverse gluonium potential model with Breit-fermi hyperfine effects

We introduce a potential model of bound transverse gluons with a fictitious constitutent mass. The gluonic Breit hamiltonian due to one gluon exchange is derived, and its effect on thegg spectrum is estimated; hyperfine corrections are large, but not nonperturbatively so. We find a degenerate (0⁺⁺, 0^?+) ground state and a first 2⁺⁺ excitation at ～1.2M ₀. Our list ofgg states disagrees with some sources, due to the absence of unphysical longitudinal degrees of freedom in the model.     

The beam quality of nonparaxial Hermite-sine-Gaussian beam

Based on the theory of the second intensity moment of nonparaxial scalar beam and the method of angular spectrum, the expressions for the far-field divergence angle, waist width and M² factor of nonparaxial Hermite-sine-Gaussian (HSiG) beams are derived. Calculation and analysis show the dependence of the far-field divergence angle of nonparaxial HSiG beams on the parameter w₀/λ, as well as on order m, And it with even and odd orders approach 73.898° and 63.435° as w₀/λ → 0. With increasing order m and the parameter w₀/λ, the waist width increase monotonously, which is same as paraxial case. But nonparaxial M² factor is different from paraxial case, it cannot only less than 1, but also approach 0 as w₀/λ → 0.     

Observation of strongly deformed ground-state configurations in184Au and183Au by laser spectroscopy

Resonance ionization mass spectroscopy (RIMS) and pulsed-laser induced desorption (PLID) have been combined in order to study the isotope shift (IS) and hyperfine structure (HFS) of¹⁸⁴Au (T_1/2=53 s) and¹⁸³Au (T_1/2=42 s) in the 6s²S_1/2 → 6p²P_1/2 (λ=267 nm) transition. The Au isotopes were obtained as daughters in the decay of^184,183Hg produced and mass separated at the new ISOLDE-3 facility at CERN. It was found that the strong deformationβ ₂}-0.25 setting in at¹⁸⁶Au persists down to¹⁸³Au.     

Internal conversion coefficients and penetration effect for the 279 keV transition in203Tl

The internal conversion process of theM1+E 2 mixed 279 keVγ-ray transition in the decay of²⁰³Hg has been reinvestigated. The emission rate of theK-shell internal conversion electrons was determined with an electron X-ray coincidence measurement using a magneticΒ-spectrometer and a Si(Li) detector of high energy resolution. Conversion electron ratios were obtained from electron spectra recorded as a function of momentum. The disintegration rate has been taken from measurements with a calibrated NaI(Tl)γ-ray spectrometer. Following results have been deduced: α=0.2279±0.0024, α _K =0.1653±0.0017, α _L =0.0475±0.0013,K/(L+M+?)=2.64±0.03,K/L=3.48±0.12,L/(M+N+ ?)=3.14±0.12. On the basis of the experimental results on theK-shell internal conversion coefficient,α _k , and the conversion ratioK/(L+M+?) the penetration effect on the internal conversion of theM1 part and the mixing ratio,δ ², of the 279 keVγ-ray transition in²⁰³Tl have been studied. Calculations were made using Hager and Seltzer's formalism and their theoretical internal conversion coefficients. The results are consistent with a mixing ratio ofδ ²=1.32±0.11 and a penetration parameter ofλ=6.8 ±0.8.     

A measurement of the ratio GE/GE of the proton form factors at very low momentum transfer

The ratioμG _EG_M of the proton form factors was determined by measuring the electron scattering cross section of the proton relative to that of¹²C. Data were taken atq ²=0.09, 0.16, 0.25, and 0.36 fm^?2, yielding a weighted mean ofμG _E/G_M=1.01±0.03.     

Quasielastic nucleon and hyperon production by neutrinos and antineutrinos with energies below 30 GeV

The cross sections of neutrino and antineutrino quasielastic reactions \(vn \to \mu ^ - p,\bar vp \to \mu ^ + n,\bar vp \to \mu ^ + \Lambda\) were studied in the neutrino energy range between 3 and 30 GeV. In comparison withV-A theory axial mass parameters ofM _A =(1.06±0.05±0.14) GeV/c² from neutrino andM _A =(0.71±0.10±0.20) GeV/c² from antineutrino data were found. The total cross-section for the hyperon production process can be described byM _A =1.0 GeV/c².