On the β-decay 210Bi(RaE) → 210Po(RaF)

It was the aim of the present work to extract nuclear wave functions directly from experimental data of β-transitions. As a favourable example the 1^? (1.153 MeVβ^?)0⁺ β-transition of ²¹⁰Bi(RaE) was studied. The results obtained are compared with theoretical wave functions and good quantitative agreement, especially for the ground state of the daughter nucleus ²¹⁰Po, was found. It is explicitely demonstrated how, in this case, the higher order terms of the transition matrix elements contribute. The results for the matrix element ratios μ and Λ are discussed. In particular it is shown that it is not possible to test CVC theory by examining Λ.     

Further investigation of the γ-transitions in Λ4H and Λ4 hypernuclei

The γ-spectra induced by stopped K^? mesons in ⁶Li and ⁷Li targets in coincidence with the accompanying charged pions and π⁰ mesons. The γ-line at (1.04 ± 0.04) MeV observed with charged pions was identified as a γ-transition in _Λ⁴H, whereas the γ-line at (1.15 ± 0.04)_MeV observed with π⁰ mesons was ascribed to a γ-transition in _Λ⁴He. Using these new values for the excitation energies of the 1⁺ levels of _Λ⁴H and _Λ⁴He hypernuclei, the phenomenological ΛN potential for the s-state interaction was recalculated.     

Calculation of A Λp invariant-mass distribution in the reaction K−d → π−Λp

The Λp invariant-mass distribution in the reaction K^?d → π^?Λp, which is observed Cline et al., has two enhancements: just below the ΣN threshold and just above the ΛN threshold. We have calculated the Λp invariant mass distribution with the two-channel formalism. It has been well discussed in our previous paper that the enhancement just below the ΣN threshold is mainly due to a Λp resonance. In our previous paper, we have interpreted the enhancement just above the ΛN threshold as the two-channel final state interaction or a Λp final state interaction associated with the ΣΛ conversion process. The physical meaning will be intensively discussed in this paper. In fact, we have clearly shown, in this paper, that the effect due to the ΣΛ conversion process is in the enhancement just above the ΛN threshold. If the experimental data should be interpreted by the two-step process K^?d → π^?(ΣN) → π^?Λp, the effect due to the ΣΛ conversion process should have appeared in the experimental data, although some experimental data do not show the enhancement just above the ΛN threshold.     

Properties of giant dipole resonance and the elimination of center-of-mass motion

The accuracy of eliminating the spurious state from the E1-transition strength distribution is investigated within the random-phase approximation with separabelized Skyrme forces. The E1-transition strength distribution in ¹³²Sn is considered as an example.     

Are Hyperon Resonances Required in the Elementary K +Λ Photoproduction?

We have investigated the role of hyperon resonances in the kaon photoproduction process, γ p → K ⁺Λ, by using a covariant isobar model. To this end, new experimental data are used in the fitting process, whereas the old SAPHIR 1998 data are also used for comparison. The result indicates that the Λ(1600)P ₀₁ and Λ(1810)P ₀₁ hyperon resonances can significantly reduce the χ² and, simultaneously, can increase the hadronic form factor cut-off in the background terms. This finding is different from the result of the previous studies, which showed that the Λ(1800)S ₀₁ was important for this purpose, instead of the Λ(1600)P ₀₁.     

Light quark mass differences and charge symmetry breaking in hyperon-nucleon interaction

Quantum chromodynamics based isovector isoscolar particle mixing arising out of isospin violating quark mass differences has been used to construct a new charge-symmetry breaking Λ-N interaction element. It appears that vector meson exchanges between N and a physical Λ rather than pseudoscalar exchanges provide the largest contribution to explain the binding energy difference between the mirror hyper-nuclei _ΛHe⁴ and _ΛH⁴. Prediction of the model to Λn and Λp scattering lengths have been compared with those obtained from the combined analysis of ΛN scattering and s-shell hyperfragment data. We find satisfactory agreement of our results.     

Λ0 hyperon polarization in inclusive production by 24 GeV protons on platinum

We report a search for Λ⁰ polarization in inclusive production by 24 GeV protons on platinum made on data taken at CERN. These data show Λ⁰ polarization of the same direction and magnitude and with the same p_T dependence as found at 300 GeV at Fermilab.     

Influence of gamma-radiation on the optical properties of modified polyvinyle chloride

Abstract

The optical absorption spectra of polyvinyle chloride, PVC, doped with Cd and Pb is presented. The effect of γ radiation doses in range of 2–200 Mrad on the fundamental absorption edge Λ_g was determined. On the basis of quantitative analysis of obtained data, the calculated absorption coefficient, α, the absorption index, K, and the optical energy gap E_opt, were found to be radiation and dopant dependent. The results are discussed on the basis of the radiation induced degradiation of PVC.     

Measurement of the production cross section for charmed baryons in proton–nucleus interactions at 70 GeV

The results of an analysis of data from the SERP-Е-184 experiment devoted to studying mechanisms of the production of charmed particles in proton–nucleus interactions at 70 GeV and their decays are presented. The data in question were obtained upon irradiating the SVD-2 active target consisting of carbon, silicon, and lead plates with a beam of 70-GeV protons. A detailed simulation on the basis of the FRITIOF7.02 and GEANT3.21 code packages made it possible to optimize event-selection criteria and to calculate the detection efficiency for Λ_c⁺ baryons. After selecting a signal from the threebody decay of a Λ_c⁺ baryon, the inclusive cross section for its production at near-threshold energies, its lifetime, and the parameter of the A dependence of the cross section were found. The Λ_c⁺ -baryon yields are tabulated along with data from other experiments and theoretical predictions.     

Polarization of Λ0 hyperons as a signature for the quark-gluon plasma

The momentum distribution of Λ⁰ hyperons produced from the quark-gluon plasma (QGP) in ultra-relativistic heavy-ion collisions is calculated in dependence on their polarization. The momentum distribution of Λ⁰ hyperons is defined by matrix elements of relativistic quark Wigner operators, which are calculated within the effective quark model with chiral U(3)×U(3) symmetry and the quark-gluon transport theory. We show that the polarization of the Λ⁰ hyperon depends on the spin of the strange quark that agrees well with the DeGrand-Miettinen model. We show that Λ⁰ hyperons, produced from the QGP, are fully unpolarized. This means that a detection of unpolarized Λ⁰ hyperons, produced in ultra-relativistic heavy-ion collisions, should serve as one of the signatures for the existence of the QGP in intermediate states of ultra-relativistic heavy-ion collisions.     

Kaonic atoms and the Λ(1405)

Kaonic shifts and widths for ¹²C and ³²S are analysed using an optical potential, which selectively incorporates nuclear shell structure aspects as well as effects of Λ(1405) dynamics inside the nucleus. Good agreement with data is found and suggests a moderately repulsive interaction of the Λ(1405) with surrounding nucleons.     

Anomalies in the surface impedance penetration depth in ferromagnetic superconductors

We have investigated the surface impedance penetration depth, Λ, of ErRh₄B₄ and Er_0.5Ho_0.5Rh₄B₄ both experimentally and theoretically. For ErRh₄B₄, owing to the critical spin fluctuations just above T_s ( > T_c2), the critical temperature at which surface ferromagnetism appears, Λ^?1 decreases smoothly as T decreases toward T_s. For Er_0.5Ho_0.5Rh₄B₄, the decrease in Λ^?1 owing to spin fluctuations for T ? T_c2 is very small, and Λ^?1 decreases abruptly at T_c2. Theoretical values of Λ^?1 are in good agreement with the data.     

ΣΛ Conversion in ΛH and in other S-shell hypernuclei

The binding energy of the Λ-particle in the $\text{J =}\text{1}\text{2}\text{and}\text{3}\text{2}$ states of _Λ³H and the doublet and quartet Λ-d scattering lengths are calculated with a separable ΛN-ΣN potential matrix, fitted to experimental data in ΛN and ΣN channels. The dependence of the results on ΛΣ coupling is explained in terms of a perturbative treatment of ΛΣ coupling. This perturbative treatment is also applied in a qualitative discussion of the effects of ΛΣ conversion in the J = 0 and 1 states of _Λ⁴H-_Λ⁴He and in the $\text{J =}\text{1}\text{2}$ state of _Λ⁵He. The importance of three-body ΛNN forces caused by ΣΛ coupling is stressed.     

THE SYNTHESIS AND SPECTRAL CHARACTERIZATION OF NEW Cu(II), Ni(II), Co(III), AND Zn(II) COMPLEXES WITH SCHIFF BASE

ABSTRACT

Cu(II), Ni(II), Co(III) and Zn(II) complexes with Schiff base have been prepared. Ligand is derived from condensation of 1,2-bis(p>-aminophenoxy)ethane and 2- hydroxynaphthalin-1-carbaldehyde. The complexes have been characterized by elemental analyses, Λ_M, IR, UV-VIS, ¹H NMR, ¹³C NMR and magnetic measurements. The ligand is coordinated to the central metal as a tetradentade ONNO ligand. The four bonding sites are the azomethine nitrogen and aldehydic -OH groups.     

The Λb lifetime in the light front quark model

The enhancement of the Λ_b decay width relative to B decay due to the difference in Fermi motion effects in Λ_band B is calculated in the light front quark model with the simplifying assumption that Λ_bconsists of a heavy quark and a light scalar diquark. In order to explain the large deviation from unity in the experimental result for τ(Λ_b)/τ(B), it is necessary that the diquark be light and the ratio of the squares of the Λ_b and B wave functions at the origin be ?1.     

Inclusive Production Λc in the e+e− - Annihilation

In the framework of the quark-diquark model of baryons, Λ_c can be considered as constituent c quark and ud diquark. In hadronizasion process baryon Λ_c can be produced from ud scalar diquark and c quark fragmentation. So in this work, in the lowest order of perturbative QCD, fragmentation functions c → Λ_c and ud → Λ_c are calculated and finally in the electron-positron annihilation in LEP, the inclusive cross section production of Λ_c is calculated about pole of z⁰.     

Q-phonon scheme in the collective nuclear model

The Q-phonon scheme developed on the basis of the algebraic collective nuclear model is discussed. It is shown that, within this scheme, low-lying collective states of even-even nuclei can be described to a precision higher than 90% of the norm by using one or, at maximum, two components of the Q-phonon basis constructed by applying a fixed number of the quadrupole operators Q to the exact ground state of the system. Various applications of this approximate scheme are discussed. It is shown that, by using this scheme, the relations between several E2-transition probabilities or between the energies of the collective states can be derived. It is also shown that the Q-phonon scheme can be used to extract information about the equilibrium shapes of nuclei and their fluctuations from data on the E2-transition probabilities.     

Λ0 polarization in ultrarelativistic nucleus-nucleus collisions

We study the polarization of Λ⁰’s produced in ultrarelativistic heavy-ion collisions. We argue that when the density of participants in the reaction is below the critical value for the production of a Quark-Gluon Plasma (QGP), recombination processes dominate the Λ⁰ production cross section and hence, Λ⁰’s are polarized. However, when the density of participants is above the critical value for QGP formation, coalescence processes dominate Λ⁰ production, giving rise to a reduction in the Λ⁰ polarization. For densities below the critical density for QGP production, we describe Λ⁰ polarization in terms of the DeGrand-Miettinen model and correct for the effects introduced by multiple scattering of the produced Λ⁰ within the nuclear environment.     

Nonlinear science abstracts

The class of exactly integrable non-linear evolution equations (NLEE) related to the general first order n × n linear problem is studied. The set of independent scattering data $\text{J}$ is determined and trace identities are obtained. Next we use a special integro-differential operator Λ and obtain the expansions of the potential and its variation in the eigenfunctions of Λ. These enable us to consider the inverse scattering method as a generalized Fourier transform and to write down in a compact form the integrals of motion. We prove that there exist a hierarchy of Hamiltonian structures generated by Λ. At the end we calculate the symplectic form in terms of the scattering data variations.