Geometry of the effective Majorana neutrino mass in the 0νββ decay

The neutrinoless double-beta (0νββ) decay is a unique process used to identify the Majorana nature of massive neutrinos, and its rate depends on the size of the effective Majorana neutrino mass <m>_ee. We put forward a novel ‘coupling-rod’ diagram to describe <m>_ee in the complex plane, by which the effects of the neutrino mass ordering and CP-violating phases on <m>_ee are intuitively understood. We show that this geometric language allows us to easily obtain the maximum and minimum of |<m>_ee|. It remains usable even if there is a kind of new physics contributing to <m>_ee, and it can also be extended to describe the effective Majorana masses <m>_eμ, <m>_eτ, <m>_μμ, <m>_μτ and <m>_ττ which may appear in some other lepton-number violating processes.     

Static properties of type-II superconductors at arbitrary temperature and induction

A concise expression for the free energy of clean type-II superconductors is given from which magnetization curves, gap and field are easily calculated for 0 < T < T_c and 0 < B < H_c2.     

Very-low-frequency ac susceptibility of the spin-glass system PrPy (y ⪅ 1)

The frequency dependence of the ac susceptibility, χ_ac, is reported for off-stoichiometric PrP_y (y ? 1) for 0.003 < f < 10⁴ Hz and for temperatures 1.4 < T < 20 K. For this spin-glass system, T_f, the temperature at which χ_ac is a maximum, reaches a minimum and constant value for f ? 0.1 Hz. The complex initial susceptibility for 0.003 < f < 0.03 Hz is presented.     

Density correlations of hadron gas and the origin of early multiplicity scaling

We will define a sequence of functions called density correlations which measure statistical correlations between momentum space densities of particles in the ensemble of inelastic final states produced by scattering a pair of hadrons. Then we will show that early multiplicity scaling of the distribution of charged particles produced by pp collisions can primarly be explained by the assumption that fluctuations of the density of charged particles are quite random and therefore higher correlation functions are small in an appropriate sense, combined with the assumption that the first three density correlations fulfill an approximate form of Feyman scaling at small values of x. These assumptions will aslo be used to derive an expression for the scaling function Ψ(η) which is completely determined by <N²>_S/<N>_S² and <N³>_S/<N>_S³, and recursion relation to calculate <N^m>_S/<N>_S^m, m ? 4, from <N²>_S/<N>_S² and <N³>_S/<N>_S³. The prediction for Ψ(η) accurately reproduces data in the interval 0.2 ? η ? 3.1, 50 GeV/c ? p_L ? 303 GeV/c, and the predictions for <N_S>^m/<N>_S^m, 4 ? m ? 10, agree with observed values in the interval 50 GeV/c ? p_L ? 303 GeV/c.     

Interrelationships between 3-T-MRI-derived cortical and trabecular bone structure parameters and quantitative-computed-tomography-derivedbone mineral density

Recently, 3-T magnetic resonance imaging (MRI) has been introduced for bone imaging. Through higher signal-to-noise ratios, as compared to 1.5-T MRI, it promises to be a more powerful tool for the assessment of cortical and trabecular bone measures. The goal of our study was to compare MRI-derived cortical and trabecular bone measures to quantitative computed tomography (QCT)-derived bone mineral density (BMD). Using 3-T MRI in 51 postmenopausal women, apparent (app.) measures of bone volume/total volume, trabecular number (Tb.N), trabecular thickness (Tb.Th) and trabecular separation were derived at the distal radius, distal tibia and calcaneus. Cortical thickness (Ct.Th) was calculated at the distal radius and distal tibia. These measures were compared to QCT-derived BMD of the spine, hip and radius. Significant correlations (^?P<.05; ^??P<.001; ^???P<.0001) were found between spine BMD- and MRI-derived Ct.Th (r_radius=.55, ^?P<.05; r_tibia=.67, ^???P<.0001) and app. Tb.N (r_radius=.33, ^?P<.05; r_tibia=.35, ^?P<.05) at the radius and tibia. Furthermore, within the first 10 mm at the radius, an inverse correlation for Ct.Th and app. BV/TV (r_6mm=−.56, P<.001; r_10mm=−.36, P<.05) and app. Tb.Th (r_6mm=−.54, P<.001; r_10mm=−.41, P<.05) was found.     

Halleffekt und anisotropie der beweglichkeit der elektronen in ZnO

Hallconstant, conductivity and Hall mobility of ZnO crystals were measured as function of temperature (4 °K < T < 370 °K) and orientation. Value and anisotropy of mobility can be explained (50 °K < T < 370 °K) by polar optical scattering, deformation potential sc., piezoelectric sc. and sc. by ionized impurities. The anisotropy of mobility is caused only by piezoelectric sc. Maximum values of μ_H are reached for μ_H ⊥ c, with 2400 cm²/V sec at 40 °K and for μ_H ¦ c with 1350cm²/Vsec at 60 °. Below 50 °K Hallconstant, conductivity and Hall mobility are influenced by impurity band conduction processes. The crystals have impurity concentration in the 10¹⁶ cm^?3 range, but they show different donor activation energies depending on growth conditions: Type I: 38,4 meV (50 °K < T < 100 °K) and Type II: 20,3 meV (50 °K < T < 100 °K) and 6 meV (25 °K < T < 50 °K).     

Evaluation of fully integrated γ v p → π+π− p cross sections in the resonance region at photon virtualities 5 < Q 2 < 12 GeV2

Evaluation of fully integrated double pion electroproduction cross sections of protons was carried out at 1.4 < W < 2.0 GeV, 5 < Q ² < 12 GeV². The cross-section evaluation was obtained from an approach based on extrapolation of the double pion component of inclusive structure functions F ₁ and F ₂ from photon virtualities Q ² < 5 GeV² towards 5 < Q ² < 12 GeV². Q ²-parameterization compatible with restrictions from the Operator Product Expansion was used to conduct the extrapolation. The results will be used to extract double pion electroproduction cross sections of protons in future experiments with the new CLAS12 detector.     

Static electric quadrupole and hexadecapole moments of nuclei

Ground-state static electric quadrupole and hexadecapole moments of even nuclei are calculated microscopically. Rare-earth, actinide and neutron-deficient nuclei with 50 <Z, N < 82 and neutron-rich nuclei with 28 < Z < 50, 50 < N < 82 are studied. Fairly good agreement with experiment is found. In the actinide region, the electric moments of fission isomers are also examined.     

Electrical conduction in sputtered Si:Al films

The d.c. electrical resistivity ?(x, T) has been measured for a series of granular Si_xAl_1?x sputtered films for 0.25 < x < 0.62 and 4K < T < 300 K. Three separate behaviours are identified in ?(x, T) corresponding to extrinsic activated semiconduction, metallic conduction and electron localisation.     

K − and\bar p Production in Au + Pb Collisions at 11.5 A GeV/cProduction in Au + Pb Collisions at 11.5 A GeV/c

I will present the first results from the E864 collaboration on the production of negative kaons and antiprotons in 10% central 11.5 A GeV/c Au+Pb nucleus collisions at the Brookhaven AGS. E864 is a high rate, open geometry spectrometer, capable of measuring particle production in a range of rapidities and transverse momenta at a single setting of the spectrometer magnets. The results are derived from the analysis of over 20 million central interactions collected in the Fall 1994 run. I will report onK ^? production in a rapidity range from 1.9<y<2.2 (y _cm=1.6) and 25<pT<150 MeV/c, and $\bar p$ production from 1.2<y<2.2 and 50<pT<400 MeV/c. A comparison with previously published results from E878 is presented and the implications for $\bar \Lambda $ production are discussed.     

Dispersion relation for elastic electron-hydrogen atom forward scattering amplitude

The elastic e + H forward scattering amplitude is an analytical function in the complex energy E plane and has two cuts on the real axis: 0 < E < ∞ and ?∞ < E < ?B, B being the hydrogen ionization potential. The e+H dispersion relation contains two integrals over the right and left cuts.     

Small momentum transfer measurements of S(k) in 4He at T = 4.27 K as function of density

We report the first measurements of S(k) in ⁴He at a fixed temperature of T = 4.27 K for 126 < p < 164 kg/m³ for the momentum transfer range $\text{0.18 < k < 1.03}\text{A}\text{?}{}^{\mathrm{?1}}$. Our results are consistent with expectations at zero momentum transfer based on thermodynamics.     

Probabilities for radiative vacancy transfer from Li (i=1, 2, 3) sub-shells to the M, N and higher shells for elements with 77≤Z≤92

The probabilities for transfer of the L_i (i=1, 2, 3) subshell vacancy to the M, N and higher shells through radiative decay, ηLiJ(R), have been deduced for the elements with 77≤Z≤92 using the measured L X-ray production cross-sections at (i) the 59.54 keV γ-rays such that BL₁<Einc<BK and (ii) the K X-rays of a suitable secondary target chosen such that BL₃<EKα<BL₂ and BL₁/L₂<EKβ<BK; where BK/Li is the K shell/L_i subshell ionisation threshold of the target element. The deduced probabilities are compared with those calculated using the radiative and nonradiative transition rates based on the Dirac-Fock (DF) and the relativistic Dirac-Hartree-Slater (RDHS) calculations, respectively.     

Quantum Tunneling and Caustics under Inverse Square Potential

We examine the quantization of a harmonic oscillator with inverse square potential V(x)=(mω²/2) x²+g/x² on the line −∞<x<∞. We find that, for 0<g<3?²/(8m), the system admits a U(2) family of inequivalent quantizations allowing for quantum tunneling through the infinite potential barrier at x=0. These are a generalization of the conventional quantization applied to the Calogero model in which no quantum tunneling is allowed. The tunneling renders the classical caustics which arise under the potential anomalous at the quantum level, leading to the possibility of copying the profile of an arbitrary state from one side x>0, say, to the other x<0.     

Measurement of Large-angle πp elastic scattering at 5 GeV/c

The differential cross-section for 5 GeV/cπ⁺p and π⁻p elastic scattering have been measured in the c.m. angular region 27° < θ_cm < 130° corresponding to 0.5 < |t| < 7.8 (GeV/c)². Dips are observed in both reactions at −t = 2.8 and 4.8 (GeV/c)² where the cross-sections are approximately 0.1 μb/(GeV/c)².     

Elastic scattering of antiprotons on protons at 5 GeV/c evidence for a backward peak

Antiproton-proton elastic scattering has been measured at 5 GeV/c. A total of 30 000 events were observed in the angular range 17° < θ_cm < 136°, corresponding to 0.3 < −t < 7.7 (GeV/c²). In addition to the known dip at −t = 0.5 (GeV/c)², we observe a structure at about −t = 2 (GeV/c)² and a backward peak with a slope4.1 ± 0.6 (GeV/c)². The extrapolated differential cross-section at u = 0 is 1.3 ± 0.8 μb/(GeV/c)².     

The thermoelectric power in AgxTiS2 and AgxNiPS3. Part II. The ionic component of the thermoelectric power

The EMF of the isothermal cells: Ag/AgI/Ag_xTiS₂: 0<x<1, T=150–200°C/Ag_xNiPS₃: 0<x<3, T=150–350°C has been measured. From the EMF-x curves the existence ranges of the 2-phase (stage I and II) regions ?0.16<x<0.32 for the Ag/Ag_xTiS₂ system at 190°C; 0.20 < x < 0.50 and 1 < x < 2 for the Ag/Ag_xNiPS₃ system at 400°C - have been determined. The results are sustained by X-ray diffraction and electrical conductivity measurements. From the EMF-T curves the partial enthalpy (ΔH?_Ag) and entropy (ΔS?_Ag) of dissolution of silver in the Ag_xSSE (solid solution electrode) materials were obtained. In the case of Ag_xTiS₂, ΔH?_Ag has a low absolute value, while ΔS?_Ag is distinctly positive. The EMF of the Ag/Ag_xNiPS₃ system also has a positive temperature coefficient. Furthermore, the ionic component of the thermoelectric power, ΔE/ΔT, of the thermogalvanic cells: Ag/AgI/Ag_xSSE/AgI/Ag Ag_xTiS₂: 0 < x < 1, T = 150–200°C( T ) (T+ΔT) Ag_xNiPS₃: 0 < x < 1, T= 150–350°C has been measured. The kinetically important heat of transport of silver ions in the Ag_xSSE materials has been determined in two ways: first from the dependence of the ionic Seebeck coefficient (?_Ag+) on reciprocal temperature; and second from direct calculation, using the data for ?_Ag+ and ΔS?_Ag. The heat of transport is much smaller than the activation enthalpy for Ag⁺-conduction, indicating a high ionic polaron binding energy in these materials.     

Photon statistics in resonance fluorescence from laser deflection of an atomic beam

There is a simple relationship between the photon statistics in resonance fluorescence and the statistics of the momentum transferred to an atom by a plane traveling wave. We use this relation and the theory of atomic motion in resonant radiation to derive expressions for the mean <n> and the variance <(Δn)²> of the number of photons emitted in a given time by a two-level atom in a coherent exciting field. We find, in addition to the sub-poissonian statistics [<(Δn)²> less than <n>] previously reported for the case of resonant excitation, that super-poissonian photon statistics [<(Δn)²> greater than <n>] occur in resonance fluorescence for certain off-resonance cases. It is suggested that the sub-poissonian and the super-poissonian emission statistics might be demonstrated in a simple photodeflection experiment.     

E0/E2 and E2/M1 multipole mixing amplitudes of γ-transitions in 192Pt

Angular correlation measurements of conversion electrons and γ-rays in ¹⁹²Pt following the decay of ¹⁹²Ir (74 d) have been made. In particular, the 296 keV e^?-316 keV γ correlation was measured in order that the electric monopole admixture in the 296 keV transition could be determined. The results of the angular correlation coefficients measured here and the ratio of K-shell to L_III shell conversion electrons measured by others are: ?0.09 < q < +0.26 as +62 < λ < +92 or ?0.29 < q < ?0.06 as ?5 < λ < +45. A possible explanation of the disagreement between two earlier measurements is suggested. The angular correlation coefficients for the measured e^?-γ and γ-γ cascades and the derived multipole mixing ratios are tabulated and compared with other recent measurements and with the predictions of the Kumar-Baranger nuclear model.     

Photoemission study of Pd Zr and Cu Zr alloys

The XPS valence bands and core levels of the alloys Pd_1?xZr_x (0<x<1) and Cu_1?xZr_x (0<x<1) have been measured. The alloys prepared by coevaporation are crystalline — but their valence band spectra are close to those of the metallic glasses of the same compositions. The large valence band and core level shifts observed for Pd can be explained by a simple theory, not necessitating the postulation of a new type of bonding in these systems.