Saturation of counterterms by resonances inK ����e + e ? decays

The decaysK ⁺???? ⁺ e ⁺ e ^?,K _S???? ⁰ e ⁺ e ^? andK _L???? ⁰ e ⁺ e ^? are reinvestigated within the framework of chiral perturbation theory. The counterterms induced by strong, electromagnetic and weak interactions are determined assuming the resonance exchange. The weak deformation model, the factorization model and the largeN _c limit are used to create a weak Lagrangian. It is found that the results of the first two approaches depend on theH ₁ coupling, defined in the effective chiral Lagrangian of theO(p ⁴) order. The set of parameters used in the extended Nambu and Jona-Lasinio model can accommodeteK ⁺???? ⁺ e ⁺ e ^? decay rate within the factorization approach. The CP violatingK _L???? ⁰ e ⁺ e ^? decay rate is discussed.     

Production of neutral MSSM Higgs bosons ine + e ? collisions: a complete 1-loop calculation

We present the first complete 1-loop diagrammatic calculation of the cross sections for the neutral Higgs production processese ⁺ e ^???Z ⁰ h ⁰ ande ⁺ e ^???A ⁰ h ⁰ in the minimal supersymmetric standard model. We compare the results from the diagrammatic calculation with the corresponding ones of the simpler and compact effective potential approximation and discuss the typical size of the differences.     

Nuclear Quadrupole Interactions in Nuclear Quadrupole Resonance Detection of Energetic and Controlled Materials: Theoretical Study

There has been a growing interest in nuclear quadrupole resonance (NQR) techniques useful for the detection of explosives and drugs in solid state systems. This paper uses the first-principles one-electron Hartree?CFock theoretical method to study the nuclear quadrupole interaction parameters e ² qQ and ?? for the ¹⁴N nuclei in the explosives RDX and ??-HMX as well as the drugs cocaine and heroin. It has been found in our earlier published investigations reviewed here that there is very good agreement for our calculated e ² qQ and ?? for ¹⁴N, for all these four systems, and experiment. We also present our unpublished theoretical results for cocaine with an HCl molecule attached. We successfully explain quantitatively the drastic decrease in e ² qQ in going to cocaine-HCl from cocaine-free base as well as the observed substantial increase in ?? and discuss the implications of these dramatic changes for NQR detection in general.     

Measurement of the cross section for the e + e ? → ωπ0 → π0π0γ process in the energy range of 1.1–1.9 GeV

The cross section for the e ⁺ e ^? ?? ???⁰ ?? ??⁰??⁰?? process has been measured in the energy range of 1.1?C1.9 GeV. The measurement has been made with the Spherical Neutral Detector at the VEPP-2000 e ⁺ e ^? collider. The data in the energy range of 1.1?C1.4 GeV are in agreement with the earlier measurements with the SND and CMD-2 detectors. The cross section has also been measured above 1.4 GeV.     

Two- and three-dimensional analysis of bose-einstein correlations in�� +/K+p interactions at 250 GeV/c

The NA22 data on?? ^? ?? ^? correlations are analyzed in terms of a number of two- and three-dimensional parametrizations (Gaussian space-time, Goldhaber, Bowler string-like, Bertsch hydrodynamical, Kopylov-Podgoretskii, etc.). Contrary to the results obtained for e⁺e^? and??p collisions, the Goldhaber parametrization, as well as string-like models, fail in describing the hadron-hadron data. Better fits are obtained in the framework of surface-emitting fireball-like models, both when including and excluding hydrodynamical expansion of nuclear matter. Our results indicate that pion radiation occurs at earlier stages of matter evolution than in nuclear collisions.     

The 3–3–1 Model with RH Neutrinos and Associated ZH Production at High-Energy ${\bf \textit{e}}^{+}{\bf \textit{e}}^{-}$ Collider

In the context of SU(3) _C ?? SU(3) _L ?? U(1) _X (3–3–1) model with right-handed neutrinos, we study the Higgsstrahlung process e ^?+? e ^???→ZH and calculate the cross section of this process at leading order. Our numerical results showed that the production cross sections for this process can be significantly large as \(M_{Z'}\approx \sqrt{s}\). With reasonable values of the Z′ mass M _Z′, Z′ exchange can generate large corrections to the cross sections of this process, which might be detected in the future high-energy linear e ^?+? e ^??? collider experiments.     

Radiative asymmetry around the resonance in e+e−→μ+μ−

Under the assumption that the ψ is a pure 1^?? vector particle we have calculated the angular asymmetry in the process e⁺e^?→μ⁺μ^? around the resonance. We find that the asymmetry, calculated in the soft photon limit, becomes very small around the resonance.     

Neutron-rich hypernuclei in the chiral soliton model

The binding energies of neutron-rich strangeness S = ?1 hypernuclei are estimated in the chiral soliton approach using the bound state rigid oscillator version of the SU(3) quantization model. Additional binding of strange hypernuclei in comparison with nonstrange neutron-rich nuclei takes place at not large values of atomic (baryon) numbers, A = B ?? ??10. This effect becomes stronger with increasing isospin of nuclides, and for the ??nuclear variant?? of the model with rescaled Skyrme constant e. Binding energies of _?? ⁸ He and recently discovered _?? ⁶ H satisfactorily agree with data. Hypernuclei _?? ⁷ H, _?? ⁹ He are predicted to be bound stronger in comparison with their nonstrange analogues ⁷H, ⁹He; hypernuclei _?? ¹⁰ Li, _?? ¹¹ LI, _?? ¹² Be, _?? ¹³ Be, etc. are bound stronger in the nuclear variant of the model.     

The intermediate-massL M Higgs boson at the NLC: reducible and irreducible backgrounds to the Bjorken production channel

Both the reducible and irreducible backgrounds to the Higgs production channele ⁺ e ^???H ⁰ Z ⁰ at a Next Linear Collider (NLC) are studied, for the Standard Model (L M) Higgs boson in the intermediate-mass range. A phenomenological analysis that does not exploit any form of tagging on the Higgs decay products is assumed.     

Omegaprimes and glueballs

An analysis is presented of ρπ and ωππ systems ine ⁺ e ^? annihilation. Definite evidence is obtained for two ω′ states at masses of 1.39 and 1.59 GeV. Incorporating these states in an analysis of the corresponding channels in diffractive photoproduction indicates the presence of a new process in isoscalar diffractive photoproduction which is not present in the isovector case. The possible relationship to the anomalous ratio of the rates of ψ′ andJ/ψ decay to ρπ is raised: both point to the presence of one or moreJ ^pc =1^?? glueball states between 2 and 3 GeV.     

Relativistic Description of 3He (e, e�� p)2H

The relativistic distorted-wave impulse approximation is used to describe the ³He(e, e?? p)²H process. We describe the ³He nucleus within the adiabatic hyperspherical expansion method with realistic nucleon-nucleon interactions. The overlap between the ³He and the deuteron wave functions can be accurately computed from a three-body calculation. The nucleons are described by solutions of the Dirac equation with scalar and vector (S?CV) potentials. The wave function of the outgoing proton is obtained by solving the Dirac equation with a S?CV optical potential fitted to elastic proton scattering data on the residual nucleus. Within this theoretical framework, we compute the cross section of the reaction and other observables like the transverse-longitudinal asymmetry, and compare them with the available experimental data measured at JLab.     

3He Transverse Electron Scattering Response Function with �� Degrees of Freedom

A calculation of the ³He transverse (e, e??) inclusive response function, R _T , which includes ?? degrees of freedom is performed using the Lorentz integral transform method. The resulting coupled equations are treated in impulse approximation, where the NNN and NN?? channels are solved separately. R _T is calculated for the breakup threshold region at a momentum transfer of q?=?862 MeV/c.     

AnomalousZ�� effects in the WW channel at NLC

We consider the virtual signals of aZ?? of very general type in the processe ⁺ e ^???W ⁺ W ^? at a future linear collider (NLC). We show that possible deviations from the SM predictions in this channel are related to similar deviations in the purely leptonic one in a way that is only characteristic of thisZ?? model, and not in general of possible competitor models with anomalous gauge couplings.     

Production of π0ρ0 pair in electron-positron annihilation in the Nambu-Jona-Lasinio model

The process e ⁺ e ^? ?? ??⁰??⁰ is described in the framework of the expanded NJL model in the energy region from 0.9 to 1.5 GeV. The contribution of intermediate state with vector mesons ??(782), ??(1020), and ???(1420), where ??? is the first radial excitation of ?? meson, was taken into account. Results obtained are in satisfactory agreement with experimental data.     

Inelastic Electron Transport Through a Carbon Fullerene Junction

Effects of inelastic electron–phonon interactions and different contact geometries on the electron transport and thermoelectric properties of the C₆₀ molecule are studied by Green’s function theory within the framework of polaron transformation. It is seen that the current (I _e ) and energy flux (I _Q ) values with respect to the contact types are ordered as I _e/q (C ₁)?I _e/q (C ₆)?I _e/q (C ₅). The results reveal that the thermopower–energy curves have strictly monotonic character which show the staircase structures. Their stair numbers depend on contact types and presence of electron–phonon interactions. It is shown that the oscillatory behavior of thermal conductance is dramatically dependent on contact types and e–p interactions. Also, the values of the dimensionless figures of merit (ZT ₀) lie in the interval [0.322 ×?10^??7, 0.194 ×?10^??3], and effect of contact types is small on the values of ZT ₀s.     

Comparison of quasiparticle models in the context of relativistic (e, e+, γ) plasma

The two widely studied thermodynamically consistent quasiparticle models are compared by studying the statistics and thermodynamics of relativistic plasma consists of (e, e ⁺, ??). We use different density dependent dispersion relation for electron and photon with the requirment that at high temperature thermal masses go to that of corresponding perturbative results and do the calculation self-consistently. We further compare our results with previous results.     

Strictly two-dimensional self-avoiding walks: Thermodynamic properties revisited

The density crossover scaling of various thermodynamic properties of solutions and melts of self-avoiding and highly flexible polymer chains without chain intersections confined to strictly two dimensions is investigated by means of molecular dynamics and Monte Carlo simulations of a standard coarse-grained bead-spring model. In the semidilute regime we confirm over an order of magnitude of the monomer density ?? the expected power law scaling for the interaction energy between different chains e _int ?? ?? ^21/8, the total pressure P ?? ?? ³ and the dimensionless compressibility gT = lim _q??0 S(q) ?? 1/?? ². Various elastic contributions associated to the affine and non-affine response to an infinitesimal strain are analyzed as functions of density and sampling time. We show how the size ??(??) of the semidilute blob may be determined experimentally from the total monomer structure factor S(q) characterizing the compressibility of the solution at a given wave vector q . We comment briefly on finite persistence length effects.      

The phenomenology of coloured scalars

We study the phenomenology of light scalar quarks and the properties of a new family of hadrons containing such quarks in the framework of QCD taking into account non-perturbative effects caused by a possible existence of the condensate of the colored scalar fields. We suggest that 1^?? bound state of scalar quark and antiquark may lie in the already accessible region \(20GeV< \sqrt S< 30GeV\) and be observable as resonance in PETRAe ⁺ e ^? collisions.     

Time-projection chamber for the PEN experiment

The PEN collaboration carries out a precision measurement of the ??⁺ ?? e ⁺?? decay branching ratio at the Paul Scherrer Institute (PSI, Switzerland). A special mini time-projection chamber (mTPC) has been developed for registration of particles in the pion beam. The chamber contains 14 × 10^?3 g/cm² of matter on the particle path. The chamber was successfully used during one-year-long run. Design and characteristics of the mTPC are described.     

Tests of discrete symmetries with the neutral kaon system at the KLOE and KLOE-2 experiments

The KLOE-2 experiment continues and extends the program of its predecessor KLOE in the field of discrete symmetry tests with the K meson system, among other studies which comprise light meson spectroscopy, dark matter searches and γγ physics. Together, KLOE and KLOE-2 have recorded the largest sample (almost 8 fb^??1) of e⁺e^? collisions at the energy equal to ? meson mass, amounting to 2.4 × 10¹⁰ of produced ? mesons. We report on the latest results and ongoing analyses of KLOE and KLOE-2 concerning discrete symmetry tests and measurements of symmetry-violating observables. A measurement of the CPT violation sensitive asymmetry in semileptonic decays of K˙S with 1.7 fb^??1 of KLOE data will be presented, which improves the sensitivity w.r.t. previous measurements about twice. Moreover, status of direct tests of T and CPT in transitions of neutral kaons performed with the ? →K˙SK˙L → πeν, 3π⁰(2π) processes will be reported, followed by the search of the CP-violating decay K˙S → 3π⁰ using the data recently acquired by KLOE-2.