Fluctuation study of pionisation in ultrarelativistic nucleus-nucleus interaction

The scaled factorial moments and the multifractal moments have been investigated in different??-intervals to study the dynamical fluctuation of pions produced in 200 AGeV³²S-Ag/Br interaction. In order to investigate the detail characteristics of intermittency behaviour, theF-moments are extracted up to the eighth order of moments in differentM-intervals. The analysis indicates a non-thermal phase transition and different regime of particle production during the hadronisation process.     

A new k-interval selection technique for fast atmospheric radiance calculation in remote sensing applications

A new technique is proposed to generate the k-interval parameters, including the number of k-intervals, the equivalent absorption coefficients, and the quadrature weights when using the correlated k-distribution method for the computation of spectrally integrated three-dimensional (3D) atmospheric radiance. The main difference between the proposed technique and the traditional exponential sum fitting technique is that only quadrature weights are involved in the optimization process. To avoid the ill-conditioned problem in the proposed technique, the absorption coefficients with high value are dealt with by the delta log(k) (Δlog(k)) technique instead of involving them in the fitting procedure. The performance of the proposed technique is illustrated by radiance calculation results of cloudless and cloudy atmosphere for three different band settings. Results show that there are less relative errors with the proposed optimization technique than with the Δlog(k) technique under the same number of k-intervals. However, as the absorption becomes stronger, the performance of the proposed technique gradually decreases to the Δlog(k) technique. The relative root-mean-square error (RMSE) of radiance for 3D cloudy atmosphere can be controlled in less than 2% when the number of k-intervals is less than 10 particularly for weak absorption band, the RMSEs are less than 1% with only 6 terms.     

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).     

Factorial moments and correlations in meson-nucleus interactions at 250 GeV/c

A sample of 8000 interactions of 250 GeV/c π⁺ andK ⁺ mesons on Al and Au nuclei, is used to search for intermittency effects by calculating the normalized factorial moments of order two to four. No significant effect is observed in the higher moments. Two-body rapidity correlations and Bose-Einstein correlations in these interactions are presented.     

Factorial moments,cumulants and correlation integrals in π+ p andK + p interactions at 250 GeV/c

A selected sample of 59200 π⁺ p andK ⁺ p nonsingle-diffrative interactions at \(\sqrt s \) =22 GeV is used to investigate one, two- and three-dimensional factorial moments, factorial cumulant moments, as well as correlation integrals. The rise of factorial moments and cumulants with decreasing phase-space volume is stronger when evaluated in three than in lower dimensions. Ratios of slopes are easier to obtain than the slopes themselves. Contrary to earlier findings, they turn out to depend on the dimension. The order dependence of the averaged ratios is better described by a Lévy stable law solution with μ=1.6 than by Gaussian approximation of the α-model (μ=2) or a second order phase transition (μ=0), but values μ>2 inconsistent with Lévy-type fluctuations are reached in a three-dimensional analysis. The multiparticle contributions to the factorial moments are calculated by means of factorial cumulant moments. A particular improvement of the method is that of correlation (or density) integrals. It leads to the conclusion that Bose-Einstein interference plays an important role in the intermittency effect, but indication is found for an interpretation alternative to the conventional view of Bose-Einstein correlations.     

Frequency moments and energy shifts for dilute Mössbauer impurities in metallic solids

Theoretical evaluations of frequency moments and second order Doppler shifts have been made for dilute⁵⁷Fe impurities in the high temperature limit for a harmonic solid. The resonant energy shifts have been calculated from the Green’s function of the impure crystal containing both mass disordering and force constant change terms in the crystal Hamiltonian. High temperature frequency moments for the impurity in different metallic solids are obtained from Mc-Millan ratios using standard Mössbauerf-values at room temperature. The effect of mass disordering predominates over the force constant change term in the evaluations of second order Doppler shifts and hence the frequency moments for dilute⁵⁷Fe impurities. The variation of frequency moments for the impurity with mass modified Debye-temperature of the hosts is shown for a number of metallic solids.     

Statistics of the energy dissipation rate and local enstrophy in turbulent channel flow

Using high-resolution direct numerical simulations, the height and Reynolds number dependence of high-order statistics of the energy dissipation rate and local enstrophy are examined in incompressible, fully developed turbulent channel flow. The statistics are studied over a range of wall distances, spanning the viscous sublayer to the channel flow centerline, for friction Reynolds numbers Re_τ=180 and Re_τ=381. The high resolution of the simulations allows dissipation and enstrophy moments up to fourth order to be calculated. These moments show a dependence on wall distance, and Reynolds number effects are observed at the edge of the logarithmic layer. Conditional analyses based on locations of intense rotation are also carried out in order to determine the contribution of vortical structures to the dissipation and enstrophy moments. Our analysis shows that, for the simulation at the larger Reynolds number, small-scale fluctuations of both dissipation and enstrophy show relatively small variations for z⁺?100.     

Some comments on jet fragmentation models andα s determinations

A number of interrelated topics on jet properties ine ⁺ e ^? annihilation is discussed. The need for differentα _s values in different fragmentation models is explained, with particular emphasis on the sensitivity to the choice of momentum conservation scheme in independent fragmentation models. Also other factors leading to a broad range of experimentalα _s values are discussed. Old and new methods to distinguish different fragmentation models are presented, with particular emphasis on gluon jet fragmentation properties.     

Magnetism and hyperfine interactions in EuM2Ge2 and GdM2Ge2(M = Mn,Fe, Co,Ni, Cu)

X-ray, magnetic susceptibility and ¹⁵¹Eu, ¹⁵⁵Gd Mössbauer effect studies of EuM₂Ge₂ and GdM₂Ge₂ were performed. All compounds crystallize in the ThCr₂Si₂ body centered tetragonal structure. In all compounds, except those with M = Mn and in EuM₂Ge₂, the M component carries no magnetic moment. All compounds except those with Mn are antiferromagnetic at low temperatures. In EuMn₂Ge₂ the Mn moments order ferromagnetically at 330 K and change to antiferromagnetic order when the Eu moments order ferromagnetically (9 K). This behaviour is different from that in GdMn₂Ge₂, where the Mn sublattice orders antiferromagnetically at 365 K and becomes ferromagnetic and antiparallel to the ferromagnetic Gd sublattice at 96 K. The Mössbauer studies of ¹⁵¹Eu and ¹⁵¹Gd provide values for the magnetic hyperfine fields, the quadrupole interactions and the orientation of the magnetic moments relative to the local fourfold axis (c-axis). It turns out that in the Eu compounds the easy axis of magnetization is close to the c-axis, while in the Gd compounds it is in the basal plane. In all systems, excluding those with Mn, the interatomic rare earth-rare earth distances have the dominant effect on the conduction electron charge density and polarization at the rare earth site and on the Curie point.     

Evolution of the truncated Mellin moments of the parton distributions in QCD analysis

We review evolution equations for the truncated Mellin moments of the parton distributions and some their applications in QCD analysis. The main finding of the presented approach is that the nth truncated moment of the parton distribution obeys also the DGLAP equation but with a rescaled splitting function P′(z) = z ⁿ P(z). This allows one to avoid the problem of dealing with the experimentally unexplored Bjorken-x region. The evolution equations for truncated moments are universal—they are valid in each order of perturbation expansion and can be useful additional tool in analysis of unpolarized as well as polarized nucleon structure functions.     

A consistent form of reduced density matrices of superfluids

The present paper aims at deriving a systematic expression of the second order reduced density matrixΩ ₂ in the case of a condensed system of identical spinless bosons. The derivation lends itself to generalization leading to higher order reduced density matricesΩ _n ,n>2, that are consistent with the hierarchical set of equations of motion for the differentΩ _n .     

Is there a narrow ε under the ϱ?

The possibility that a narrow ? resonance exists, approximately degenerate in mass and width with the ?, is considered. It is shown that data on π⁺π^? production near the ? mass, including the full set of joint moments in π⁺p → π⁺π^?Δ⁺⁺ as well as the moments obtained with a polarized target in π^?p → π^?π⁺n, are consistent with the existence of such a resonance. Our method, which involves a compromise two-parameter fit to the mass dependence of some moments and the mass-averaged values of all moments, indicates that a broad ? with a slowly varying phase shift and a rather low mass, 600 MeV, also fits the data. However, the two solutions could be distinguished by accurate measurements of the mass dependence of some moments, using existing data on π⁺p → π⁺π^?Δ⁺⁺, and the existence (or non-existence) of a narrow ? clearly demonstrated.     

ESR study of rare-earth ions with the effective spin of 1/2 in LiNbO3 crystals

Rare-earth ions of Nd³⁺ and Er³⁺ in nearly stoichiometric and MgO-doped LiNbO₃ crystals, respectively, have been investigated by employing an X-band electron spin resonance (ESR) spectrometer. The grown crystal was heated in Li-rich powder at 1100°C in order to make it nearly stoichiometric by the vapor transport equilibrium technique. Due to the fact that the ESR linewidth is much narrower in the stoichiometric crystal than in the congruent LiNbO₃, we were able to determine the hyperfine constants of¹⁴³Nd and¹⁴⁵Nd at 4 K. By codoping MgO into LiNbO₃, a new Er³⁺ center has been observed with a differentg-tensor. We propose that the new Er³⁺ center in Mg-doped LiNbO₃ occupies the niobium site due to the local excessive Mg²⁺ ion at the lithium site, whereas Nd³⁺ and Er³⁺ in congruent crystals reside at the lithium site. The proposal is consistent with theg-value anisotropy.     

Low-temperature spin configurations in ErFeO3 and DyFeO3

Low temperature spin configurations in ErFeO₃ and DyFeO₃ have been studied by Mössbauer spectroscopy in single crystals. In ErFeO₃ our results indicate a reorientation G_z → G_zy of the Fe³⁺ moments below 4K, already found by neutron diffraction and NMR experiments. In DyFeO₃, it is shown that the Dy³⁺ moments order in the A_xG_y or G_xA_y configuration below 3K. This ordering triggers a G_y → G_xy reorientation of the Fe³⁺ moments.     

Tensor polarization of 6Li(2.186 MeV, 3+) states produced in the reaction 9Be(p, α)6Li* at 40 MeV

A consistent theoretical analysis of polarization moments t _kq is performed for the ⁶Li(2.186 MeV, 3⁺) states produced in the reaction ⁹Be(p, α)⁶Li*. The analysis is based on the distorted-wave Born approximation implemented for finite-range forces with allowance for spin-orbit interaction. The calculated tensor moments are compared with relevant experimental data. Particle-particle angular-correlation functions and tensor moments are shown to provide radically new information about reaction mechanisms and about nuclear interactions.     

Total β-decay energies and masses of85–89Br

Experimentalβ-decay energies of neutron-rich bromine isotopes are presented. The samples were produced as mass-separated fission products by using the on-line isotope separator technique. By means of a Si(Li)-detector system,β-spectra were recorded in coincidence with differentγ-gates, and {ie173-01}-values for^85–89Br were deduced. The atomic mass excess is derived for these nuclei, and comparisons are made with mass formula predictions. The possibility of delayed-neutron emission is discussed in conjunction with information from the shape of the delayed-neutron spectra.     

Microwave and optical spectroscopy of carotenoid triplets in light-harvesting complex LHC II of spinach by absorbance-detected magnetic resonance

Absorbance-detected magnetic resonance (ADMR) of the light-harvesting complex LHC II of spinach revealed two triplet contributions, having differentD values, but equalE value (|E|=0.00379 cm^?1). The two triplets are assigned to two of the three carotenoids present in LHC II: lutein (|D|=0.03853 cm^?1) and neoxanthin (|D|=0.04003 cm^?1). The ADMR-detected Triplet-minus-Singlet (T—S) optical difference spectrum of the carotenoid (Car) triplet transition of LHC II showed, apart from bands in the Car absorption region, a contribution in the chlorophyll (Chl) absorption region due to a change in interaction between lutein and Chla at 670 nm, and neoxanthin and Chla at 670 and 677 nm. From Linear Dichroic (LD-)ADMR-detected LD-(T—S) spectra we have determined that the tripletz-axis (which corresponds roughly to the polyenal axis) of lutein and neoxanthin makes an angle of 47° and 38° with theQ _y transition moment of their adjacent Chla molecules, for the Chls absorbing at 670 and 677 nm, respectively. TheT _z triplet magnetic transition moment of lutein is parallel to the lutein singlet and triplet absorptions, whereas theT _x axis of neoxanthin makes an angle of about 20 degrees with the optical transition moments of the carotenoid molecule. The major Chla absorption bands of the optical absorption spectrum and the ADMR-detected T—S spectrum is best explained by assuming that all Chla is present in dimers. It is proposed that a free Chl dimer absorbs at 664 and 670 nm, whereas a Chl dimer bound to a carotenoid absorbs at 670 and 677 nm.     

Collinear laser spectroscopy on108g, 108m In using an ion source with bunched beam release

The hyperfine structure and isotope shift of^108gIn and^108mIn have been investigated by means of collinear fast-beam laser spectroscopy in the resonance line atλ=451 nm. The indium isotopes were prepared at the GSI on-line mass separator following a fusion evaporation reaction. For the first time, a FEBIAD ion source with bunched release of indium was used. Magnetic dipole moments, electric quadrupole moments and isotope shifts were determined. The present results lead us to assign the spinI=2 to the¹⁰⁸In (T _1/2=40 min) state. Spins and moments are discussed in the framework of thejj-coupling model.