Isospin breaking in nuclear physics: The Nolen-Schiffer effect

Using the QCD sum rules we calculate the neutron-proton mass difference at zero density as a function of the difference in bare quark massm _d—m _u. We confirm results of Hatsuda, Høgaasen and Prakash that the largest term results from the difference in up and down quark condensates, the explicitC(m _d—m _u) entering with the opposite sign. The quark condensates are then extended to finite density to estimate the Nolen-Schiffer effect. The neutron-proton mass difference is extremely density dependent, going to zero at roughly nuclear matter density.The Ioffe formula for the nucleon mass is interpreted as a derivation, within the QCD sum rule approach, of the Nambu-Jona-Lasinio formula. This clarifies theN _c counting and furthermore provides an alternative interpretation of the Borel mass.     

Contribution of higher gluon condensates to light-quark vacuum polarization

A method of classifying quark operators in QCD sum rules is suggested. The expansion coefficients of all thed≦8 bilinear quark condensates in gluon condensates are calculated. The coefficient functions at the gluon operators withd≦8 in the polarization operator ∏(q ²) of the light-quark vector current are obtained. A comparison is performed with the calculations in the covariantly constant fields and self-dual fields. The results obtained can be used in the sum rules for the ρ, ω and ? families.     

Spin mixing in colliding spinor condensates

F = 1 spinor condensates initially prepared in a double-well potential are studied in the mean field approach. First, the decoupling of the dipolar oscillation and the internal dynamics is presented. Second, the dynamical consequences of a small seed of m = 0 atoms on a system with initially well separated m = 1 and −1 condensates is explored. It is found that such a seed drives the dynamics of the m = ±1 condensates, thus departing dramatically from the behavior of binary mixtures. Original Text ? Astro, Ltd., 2009. The article is published in the original.     

A class of modified sum rules in QCD

We consider a class of modifications to the exponential QCD sum rules, replacing the energy variableq ² by (q ²) ^k withk positive integer. As a result of this modification, (i) the relative role of the condensates on the theoretical side is changed, (ii) the integral on the phenomenological side acquires a rapidly decreasing weight function and (iii) the way of approaching infinity in theq ² complex plane splits intok rays. We explicitly discuss the modified sum rules withk=1,k=2 andk=3 for the ρ meson and conclude that, unlike to thek=1 case, thek=2 andk=3 sum rules do not yield a satisfactory scheme for the prediction of the resonance parameters unless many higher condensates are known. We show that, for practical applications with the present knowledge of condensates, the standard exponential QCD sum rules are the most suitable ones out of the class considered.     

Dynamics of compositeW-bosons

We derive some constraints among the masses and couplings of theW-bosons and the vacuum condensates of some non-supersymmetric and supersymmetric theories where theW are composite particles. We deduce that in a theory where the value of the hypergluon condensate is much smaller than the value of the compositeness scale (like in the case of an unbroken supersymmetry), theW-bosons cannot be composite.     

Growth kinetics of polymer crystals in bulk

Temperature-dependent measurements of spherulite growth rates carried out for i-polystyrene, poly(ε -caprolactone) and linear polyethylene show that the controlling activation barrier diverges at a temperature which is 14K, 22K and 12K, respectively, below the equilibrium melting points. We discuss the existence of such a “zero growth temperature” T _zg in the framework of a recently introduced thermodynamic multiphase scheme and identify T _zg with the temperature of a (hidden) transition between the melt and a mesomorphic phase which mediates the crystal growth. The rate-determining step in our model of crystal growth is the attachment of chain sequences from the melt onto the lateral face of a mesomorphic layer at the growth front. The necessary straightening of the sequence prior to an attachment is the cause of the activation barrier. A theory based on this view describes correctly the observations. With a knowledge of T _zg it is possible to fully establish the nanophase diagram describing the stability ranges of crystalline and mesomorphic layers in a melt. An evaluation of data from small-angle X-ray scattering, calorimetry and optical growth rate measurements yields heats of transition and surface free energies of crystals and mesophase layers, as well as the activation barrier per monomer associated with the chain stretching. According to the theory, the temperature dependence of the crystallization rate is determined by both the activation energy per monomer and the surface free energy of the preceding mesomorphic layer. Data indicate that the easiness of crystallization in polyethylene is first of all due to a particularly low surface free energy of the mesomorphic layer.     

Dipionic decays of psions in a local derivative coupling model

A local derivative coupling model is used to study theφ′→ππ and other dipionic decays ofφ andφ″, as an alternative to theε-model. The results obtained are quite satisfactory. We findt hat the existence of theε-resonance is not essential in order to understand the dipionic decays of the psions at the present level of experimental data available. A preliminary version of this paper was presented at the 3rd High Energy Phys. Symp. held in Nov. 1976 at Bhubaneswar.     

Energy band structure of spin-1 condensates in optical lattices

The energy band structure of spin-1 condensates with repulsive spin-independent and either ferromagnetic or antiferromagnetic spin-dependent interactions in one-dimensional (1D) periodic optical lattices is discussed. Within the two-mode approximation, Bloch bands of spin-1 condensates are presented. The results show that the Bloch bands exhibit a complex structure as the atom density of m F=0 hyperfine state increases: bands splitting, reversion, intersection and loop structure are excited subsequently. The complex band structure should be related to the tunneling and spin-mixing dynamics.     

Mesophase formation in lyotropic polymers

Summary The behaviour of polymers for which the mesomorphic property is primarily related to rigidity or partial rigidity of the chain backbone is discussed. The former part of the paper includes an outline of current theories, which describe the phase equilibria of both low-and high-molecular-weight mesogens in the undiluted and diluted states. In the latter part of the paper phase behaviours of rigid and semi-rigid polymers are briefly reviewed. Detailed phase diagrams are considered for the systems poly-γ-benzyl-L-glutamate/dimethylformamide and poly-p-benzamide/dimethylacetamide-LiCl. The correlations between experiments and theory are discussed. The mesomorphic behaviour of cellulose and its derivatives and ternary systems involving two rodlike solutes or mixtures of rodlike and random coiled polymers are also considered. Experimental results provide substantial confirmation for the theoretical predictions of mesophase formation in lyotropic polymers. Paper presented at the ?Meeting on Lyotropics and Related Fields”, held in Rende, Cosenza, September 13–18, 1982.     

An order-by-order construction of low-temperature phase diagrams for classical lattice systems

An inductive algorithm is presented for the construction of phase diagrams by means of the low-temperature expansion technique. First the phase diagram is studied in the set of formal series. In each step, properties of this phase diagram are related to extremal elements of some family of convex sets. Approximations of the phase diagram in orderN are obtained by truncating all formal series at theNth term.This paper was presented at the Trebon, Czechoslovakia, Symposium September 1–6, 1986.     

The wave-particle dualism in 1992: A summary

We review the past and present theoretical and experimental situations relating to wave-particle dualism. New tests aimed at enlightening the individual behavior as awave, then as aparticle, of asingle quantum mechanical system in the same experimental run are presented. The related epistemological, philosophical, and historical backgrounds are presented in a twofold exposition taking into account thepositivistic standard Copenhagen interpretation as well as therealist de Broglian point of view.     

Fluorescence anisotropy decay study of self-association of bacterial luciferase intermediates

The fluorescence dynamics parameters of the fluorescent transient flavin-luciferase species from the typesVibrio fischeri andPhotobacterium leiognathi are presented. The fluorescence anisotropy decay is a single exponential function for both types. The correlation time is 70 ns for theP. leiognathi fluorescent transient intermediate (2°C, aqueous buffer, pH 7.0), consistent with the rotational correlation time of the luciferase macromolecule (77 kD) to which the flavin fluorophore is rigidly attached. In contrast, for theV. fischeri species the observed correlation time for the anisotropy decay function is 133 ns. This suggests that protein self-association occurs in theV. fischeri case and this is confirmed by filtration, where the fluorescent transient fromV. fischeri does not pass through a 100,000 molecular weight cutoff membrane, whereas theP. leiognathi species does. The filtration method also demonstrates self-association in the luciferase peroxyflavin and photoflavin fromV. fischeri. A monomer-dimer equilibrium also explains the previously reported high correlation times for theV. harveyi luciferase-flavin species. It is proposed that the self-association competes with the lumazine protein interaction in the bioluminescence reaction.     

Intercalation reaction kinetics: a TDPAC study of 2H-TaS2 intercalation

Summary We report on thein situ observation of the¹⁸¹Ta nuclear quadrupole interaction during electrointercalation of 2H-TaS₂ with hydrated gadolinium ions by means of time differential perturbed angular correlations (TDPAC). Paper presented at the ?V International Conference on Ternary and Multinary Compounds?, held in Cagliari, September 14–16, 1982.     

On the enhancement of the recoilless fraction in restricted geometries

The enhancement of recoilless fraction (f factor) in restricted geometries is studied. The experiments were carried out using the¹¹⁹Sn resonance in SnCl₄ molecules trapped in porous glass. A theoretical approach to explain the increase of thef factor is presented.     

Quantum Statistical Properties in Two—Species Bose—Einstein Condensates

We have studied quantum statistical properties in a zero-temperature two-species Bose-Einstein condensate system in the presence of the nonlinear self-interaction of each species,the interspecies nonlinear interaction,and the Jisephson-like tunneling interaction.It is found that the two condensates may periodically exhibit sub-Poissonian distribution.It is revealed that the correlation between the two condensates can be nonclassical,which means that there exists a violation of Cauchy-Schwartz inequality.The nonclassical effect about the correlation between the two condensates can be realized experimentally by properly preparing the total number of atoms in the two condensates.     

L-shell ionization of atoms and their subsequent decay by radiative and non-radiative transitions

The study of the ionization of atoms resulting in vacancies in their inner shells and the subsequent decay of the atomic-vacancy states by x-ray and Auger transitions continue to be an active area of interest. A rapid survey of the theoretical efforts to calculate the transition probabilities involvingL-subshells in the high-Z atoms is presented. A complete review of theL ₁-subshell yields for single-vacancy atomic states obtained by various experimental techniques is included. The production of multiple vacancies in theL shell and the role of the spectator vacancies in the decay process is discussed. A detailed case study of determining experimentally the number of multiple vacancies produced, and the x-ray fluorescence yields during ionization by heavy-ion bombardment is presented. It is established that the effect of spectator vacancies is to increase the x-ray fluorescence yields substantially.     

Comet P/grigg-Skjellerup: Ground-based observations after the encounter with the Giotto spacecraft

Summary After the encounter with the Giotto spacecraft, the comet P/Grigg-Skjellerup was observed with the 2.2 m ESO telescope. Imaging in theV andR bands and infrared photometry with theJ andH filters were performed. From the radial enhancement of the images we derived that theR frame mainly concerns the dust tail of the comet. Thus we applied the inverse numerical method of dust tail analysis in order to estimate the following cometary-grain parameters: ejection velocity, anisotropy of the emission, size distribution and loss rate. This from the observations back in time to the Giotto encounter. From infrared observation we could calculate theJ andH magnitudes and the colour indexJ−H=0.4 consistent with previous measurements of the comet. Paper presented at the 6th Cosmic Physics National Conference, Palermo, 3–7 November 1992.     

The109Ag Knight shift in the palladium-silver alloy system

The¹⁰⁹Ag Knight shiftK in the PdAg system has been observed at 298 K. The temperature dependence of the shift is presented in conjunction with the data of Narath at 4 K. The shift is found to be temperature dependent for silver concentrations less than 60 at. %. An analysis ofK in terms of thes andd electron contributions shows that thes electron density of states at the Fermi energy is in agreement with a commons band uniformly filled at the Pd and Ag sites and thatK _d is linearly related to the susceptibility of the PdAg system with both the temperature and the alloy concentration as implicit parameters.     

Analytic solution inSU(N) lattice-gauge model of Migdal

Migdal's renormalization group transformation for theSU (N) pure lattice-gauge model is solved in the weak coupling regime by a perturbative expansion in the coupling constant. The heat-kernel model is shown to be a low-order perturbative solution of the Migdal recursion relation. The parameters of the -function are fixed within theSU (N) Migdal model. The critical coupling constant of the deconfining phase transition is approximately calculated and compared with constants obtained by the heat-kernel model and numerical calculations. The improved actions for theSU (2) andSU (3) are presented for realistic lattice-gauge methods such as the Monte Carlo simulation.     

QCD sum rules: charmonium

The dimensiond=4 gluon condensateφ ₁ is determined from an analysis of charmonium, taking model dependent estimates ofd=6.8 condensates into account. ForS-waves, there is a compatibility region, where both these and model dependent higher state corrections to ground state dominance are small, enablingφ ₁ to be determined from a fit to the data. ForP-waves the estimated higher dimension contributions are large in the region of ground state dominance, and noφ ₁ determination is possible. Theφ ₁ value obtained from the fit to theS-wave ratios is 3 5 times bigger than that obtained by RRY using the plateau method. The methods are compared for the vector current. We show that the higher state correction used by RRY does not fit the data; and that the plateau method is much more sensitive to thed=6.8 condensates than the ratio used here. When reasonable estimates of both these and the higher state corrections are taken into account, there is compatibility between the two methods.