P-Matrix analysis of the dibaryon1 D 2 resonance

We study the relation between intermediate energy nucleon-nucleon scattering and the eigenstates of the bag model using theP-matrix formalism. Data of existing phase-shift analyses are employed to calculate theP-matrix for the coupled¹ D ₂(pp) and⁵ S ₂(NΔ) channels in the energy region above the Δ-isobar production threshold. TheP-matrix calculated for the equivalent hadronic bag radiib=1.4?1.5 fm is shown to have a pole in the mass range 2.31–2.34 GeV in agreement with the MIT bag model prediction of theI=1,J ^P =2⁺ 6-quark state with the mass 2.34 GeV. The hadronic shift of this state is shown to be ≈200 MeV; the dibaryon pole of theS-matrix is located at the energy 2.15–2.17 GeV with the width ≈100–200 MeV.     

On the π3He3He coupling

A critical discussion of different methods of estimation of the coupling constant f_π³He³He² is given. It is claimed that at present the best way of obtaining information on this coupling constant is to extrapolate certain differential cross sections, in particular, of the elastic ³He³H scattering, to the pion pole. The resulting value f_π³He³He² = 0.055 ± 0.020 is smaller than the corresponding pion-nucleon value. It supports the expected shadowing effects inside the nucleus but disagrees with other more model-dependent estimations.     

Excited quark-quark interactions in a bag model

We calculate the colour magnetic and electric fields,B ^a andE ^a , in the static cavity approximation of the MIT bag model. This is done rigorously for all direct and exchange four-currents of quarks in theS _1/2,P _1/2 andP _3/2 bag states. We then find the quark-quark colour interaction for direct and exchange diagrams. The one-pion exchange diagrams due to chiral symmetry are also calculated.     

Error propagation in extrapolated nuclear mass predictions

The properties of the error of the nuclear masses calculated from the transverse mass relations are analysed. The work assumes that the calculated errors of the nuclei whose masses are known experimentally behave as a sample selected randomly from a normal population having a zero mean and a standard deviationσ. It is found that the errors of the calculated masses of nuclei far from the line of beta-stability behave asc ₁ d ^3/2 wherec ₁ is a constant andd is the distance of the nucleus from the line of beta-stability. It is shown also that the errors related to the calculated mass differences behave asc ₂ d ^1/2 wherec ₂ is another constant.     

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.     

Fission of bags by spontaneous quark-antiquark pair production in supercritical colour fields

We describe the fission of heavy quarkonia as the decay of the bag vacuum state by spontaneous creation of a light quark-antiquark pair due to super-critical colour-electric fields. In the adiabatic approximation the heavy quarks are reduced to two point charges fixed at the foci of a prolate ellipsoidal MIT bag. We solve the Dirac equation with the corresponding quasi-abelian potential numerically and estimate the critical heavy-quark separation, at which the energy needed to produce the light quark pair approaches zero, to be 2.2 fm for the value 4α _s /3=0.385 of the strong coupling constant and the vacuum pressureB ^1/4=235 MeV. These values have been used previously by Hasenfratz et al. to reproduce the spectra of heavy quarkonia. We show that this “critical distance” lies just above the classical turning point of thosec \(\bar c\) - andb \(\bar b\) -resonances which are presently known.     

Meson properties from a bag model compared to lattice theory and heavy ion experiments

A bag at temperature (T) with pressureB(T)=B(0)[1?(T/T _c )⁴] is shown to be consistent with recent lattice data on the π and the ρ mesons. The limiting temperature,T _l , of the pion bag from the Bekenstein entropy bound is lower than that of other mesons. This agrees with the thermal distribution of π,K and the ρ in heavy ion collisions, which (unlike proton-nucleus or pp data) show a marked difference inT of pion and other mesons in the mid-rapidity region.     

Phase transition to color-flavor-locked matter and condensation of Goldstone bosons in neutron star matter

Deconfinement phase transition and condensation of Goldstone bosons in neutron star matter are investigated in a chiral hadronic model (also referred as to the FST model) for the hadronic phase (HP) and in the color-flavor-locked (CFL) quark model for the deconfined quark phase. It is shown that the hadronic-CFL mixed phase (MP) exists in the center of neutron stars with a small bag constant, while the CFL quark matter cannot appear in neutron stars when a large bag constant is taken. Color superconductivity softens the equation of state (EOS) and decreases the maximum mass of neutron stars compared with the unpaired quark matter. The K⁰ condensation in the CFL phase has no remarkable contribution to the EOS and properties of neutron star matter. The EOS and the properties of neutron star matter are sensitive to the bag constant B, the strange quark mass m_s and the color superconducting gap Δ. Increasing B and m_s or decreasing Δ can stiffen the EOS which results in the larger maximum masses of neutron stars.     

A new classical solution of the Yang-Mills field equations

The MIT bag theory is used to calculate the quarl anti-quark annihilation amplitude for the ??γ transition and produces m_?²/∫_? = 0.13 compared to the experimental result of 0.11.     

On the linear chain with arbitrary masses and force constants. I. Correlation functions

Simple expressions are derived for the time dependent correlation functions of certain phase functions of the classical linear (harmonic) chain having arbitrary masses and force constants. This is done for a statistical distribution τ (H, P) in phase space depending arbitrarily on the energy H and the total momentum P, which then is specialized to the uniform distributions τ_H, on the surface of constant energy, and τ_H,P, in the intersection of surfaces of constant energy and total momentum. In a subsequent paper²) the results will be used to draw conclusions on the ergodic properties of the phase functions.     

Instanton effects on the interaction potential between light quarks and the isomultiplet mass splitting of baryons

On the basis of current assumptions of instanton theory we derive strictly the explicit dependence on the masses and spins of the instanton induced potential between a pair of light quarks in baryons, namelyV ₁₂=γ+β(m _* ^1+α )(m _* ^2+α )η(1-σ ₁ησ ₁), wherem _i ^* andσ _i (i=1.2) are respectively the mass and Pauli spin of theith quark. On the additional basis of the MIT bag model, we obtain γ=c/R ³ and β=b/R ³>0, and α>0 is independent of the radiusR of the baryon. The magnitudes of the parametersb and α are also estimated. The MIT bag model is improved by taking into account this potential. Isomultiplet mass splitting formulas are derived in good agreement with experiment.     

On the neutron charge radius and the new experiments proposed for the precise (n,e)-scattering length measurement

Strict comprehensive treating the generalized Dirak equation for nucleon in external electro-magnetic field argues quite clear that there is no physical reason to bring into consideration so-called “Foldy-term” while obtaining the neutron mean square charge radius < r _n ² >, caused by an electric charge distribution inside a nucleon, from the experimental value of the (ne) — scattering length b _ne , that term being, as a matter of fact, fictitious one. Consequently, the representing of the experimental quantity b _ne as a sum of “Foldy length” b _F and “intrinsic” one b_I, even so splitting the total value of < r _n ² > in “Foldy” and “intrinsic” < r _in ² >, turn out of having no profound physical sense, being rather ambiguous in actual fact. The formal phenomenological relation, originated from the generalized Dirak equation for nucleon, of the quantities b _ne , < r _n ² >, and neutron anomalous magnetic moment μ is inquired. Concise treating < r _n ² > in the frame-work of up-to-date nucleon cloudy bag model (CBM) is presented, no “Foldy term” being emerged, and < r _n ² >, calculated according this approach, provides b _ne -value which is in agreement with experimental result within accuracy of about 10%. On the other hand, the experimental b _ne -value proves to be described phenomenologically through solely the neutron anomalous magnetic moment μ with the same accuracy ～ 10%. Then the necessity of obtaining b _ne -value with more reliable accuracy then in previous experiments becomes obvious, corrections have to be reduced to the level of the precise declared. For these aims, two new proposed experiments have been Monte-Carlo modelled. The first renders the measurement of the energy dependence of an elastic scattering cross-section on ⁸⁶ Kr, having the unique small capture cross-section. The second one is to measure the energy dependence of neutron scattering angle anisotropy for natural Xe.     

Lithium aluminum nitride,Li3AlN2 as a lithium solid electrolyte

Single phase of Li₃AlN₂ was prepared from the mixture of Li₃N/AlN = 1.2 to 1.5 in molar ratio at 700°C and at 900°C. It crystalizes in the cubic system derived from antifluorite-type structure having the lattice parameter $\text{a = 9.470}\text{A}\text{?}$. It is a pure ionic conductor having conductivity of 5 × 10^?8ω^?1cm^?1 at room temperature and an activation energy of 52 kJ/ mol. Its decomposition voltage was 0.85 V at 104°C. The TiS₂/Li₃AlN₂/Li cell could be discharged at a constant current of 45 μA/cm² at 104°C.     

An Analysis of Charged Anisotropic Star with de Sitter Spacetime

We propose a model for charged anisotropic star in de Sitter spacetime. We have taken Krori and Barua (J. Phys. A, Math. Gen. 8, 508, 1975) metric in de Sitter spacetime with non-zero cosmological constant. The model is free from singularity. We incorporate the existence of the cosmological constant on a small scale to study the structure of anisotropic charged star. To solve the Einstein-Maxwell field equations we assume the relation between the radial and transverse pressure as p _t ?p _r =g q(r)² r ² (where g is a non-zero positive constant). The physical conditions inside the stellar model are also discussed.     

Conductivity of RbCu4Cl3+xI2−x and copper electrode reaction computerized complex analysis

Attempts to measure the conductivity of solid electrolytes having the composition RbCu₄Cl_3+xI_2?x where x=0 or 0.25 were carried out using copper and Chevrel phase electrodes Cu₂Mo₆S₈. Complex impedance diagrams showed severe polarization effects at copper electrodes. Special programs were used with a computer coupled to the impedance meter allowing measurements at constant overpotential or constant current. In contrast to usual situations, the polarization at the copper electrode is a decreasing function of the ac signal voltage and a constant quantity of electrolysing current of ≈10^?2 C cm^?2 is required to disrupt the blocking effect at the interface. Results obtained with the Chevrel phases unambiguously show that the exchange of ions between two solid phases can take place at room temperature without any interfacial overpotential. The best conductivity value of RbCu₄Cl₃I₂ was 0.475 (Ω cm)^?1 at room temperature but all the measurements revealed a marked instability towards lower values. The conductivity of RbCu₄Cl_3.25I_1.75 at room temperature is 0.36 (Ω cm)^?1 and is stable. The activation energy is 0.045 eV.     

1S0 and 3S13D1 nucleon-nucleon potentials in the quark compound bag model

For nucleons interacting via formation of the quark compound bag the resulting potential is written in a general form. Explicit examples of potentials are constructed in the ¹S₀, ³S₁ and ³S₁-³D₁ states fitted to the experimental data at T_L ? 1 GeV. As an outcome the QCB energy levels (dibaryons) and NN admixture in QCB are obtained in good agreement with theoretical predictions.     

Laser-radiofrequency double-resonance spectroscopy of methyl chloride: Hyperfine structure of the ground and ν6 states

Pure quadrupole resonances of methyl chloride have been observed using the highly sensitive method of infrared-radiofrequency double resonance inside a laser cavity. Quadrupole resonances have been observed for the ground and ν₆ states for both the CH₃Cl³⁵ and CH₃Cl³⁷ isotopes using the direct double-resonance as well as collisionally induced satellites. Most of the six hyperfine constants: the quadrupole coupling constant, eqQ; its rotational dependence, χ_J and χ_K; Hougen's coefficient, χ_D; and the spin-rotation constants, C_N and C_K, have been determined for the two states for both isotopes.     

Arguments against one-boson-exchange models of nuclear forces and new mechanism for intermediate-and short-range nucleon-nucleon interaction

Arguments against the traditional Yukawa-type approach to NN intermediate-and shortrange interaction due to scalar-isoscalar and heavy-meson exchanges are presented. Instead of the Yukawa mechanism for intermediate-range attraction, some new approach based on the formation of a symmetric six-quark bag in the state |(0s)⁶[6]_X, L=0〉 dressed owing to strong coupling to π, σ, and ρ fields is suggested. This new mechanism offers a strong intermediate-range attraction, which replaces effective σ exchange (or excitation of two isobars in the intermediate state) in traditional force models. A similar mechanism with the production of a vector ρ meson in the intermediate six-quark state is expected to lead to a strong short-range spin-orbit nonlocal interaction in the NN system, which may resolve the long-standing puzzle of the spin-orbit force in baryons and in two-baryon systems. The effective interaction in the NN channel provided by the new mechanism will be enhanced significantly if the partial restoration of chiral symmetry is assumed to occur inside the six-quark symmetric bag. A simple illustrative model is developed that demonstrates clearly how well the suggested new mechanism can reproduce NN data. Strong interrelations have been shown to exist between the proposed microscopic model and one-component Moscow NN potential developed by the authors previously and also with some hybrid models and the one-term separable Tabakin potential. The new implications of the proposed model for nuclear physics are discussed.     

Vacuum of the quantum Yang-Mills theory and magnetostatics

It is argued that since in asymptotically free Yang-Mills theories the quantum ground state is not controlled by perturbation theory, there is no a priori reason to believe that individual orbits corresponding to minima of the classical action dominate the Euclidean functional integral. To examine and classify the vacua of the quantum gauge theory, we propose an effective action in which the gauge field coupling constant g is replaced by the effective coupling $\text{g}\text{(t), t =}\text{ln}\text{[}\text{F}{}_{\mathrm{\mu \nu }}{}^{\mathrm{a}}\text{)}{}^2\text{μ}{}^4\text{]}$. The vacua of this model correspond to paramagnetism and perfect paramagnetism, for which the gauge field is F_μν^a = 0, and ferromagnetism, for which (F_μν^a)² = λ², i.e. spontaneous magnetization of the vacuum occurs. We show that there are no instanton solutions to the quantum effective action. The equations for a point classical source of color spin are solved, and we show that the field infrared energy becomes linearly divergent in the limit of spontaneous magnetization. This implies bag formation, and an electric Meissner effect confining the bag contents.