Instanton induced flavour mixing in the presence of vector mesons

An extended version of the Nambu-Jona-Lasinio model is supplemented with the 't Hooft determinant and bosonized for an arbitrary number of flavours. The resulting effective meson lagrangian is in good agreement with the experimental low-energy mesonic data. The presence of the 't Hooft determinant leads to a flavour mixing of the scalar and pseudoscalar mesons with diagonal flavour content. This instanton induced flavour mixing in the scalar and pseudoscalar channel is noticeably effected by the coupling to the vector and axial-vector meson sector. If the latter is taken into account the η?η′ mixing angle is shifted from ?31° to ?22° in good agreement with the experimental value.     

Polarization correlations in the two�Cphoton decay of hydrogen�Clike ions

Polarization properties of the photons emitted in the two?Cphoton decay of hydrogen?Clike ions are studied within the framework of the density matrix and second-order perturbation theory. In particular, we derive the polarization correlation function that gives the probability of the (two?Cphoton) coincidence measurement performed by polarization?Csensitive detectors. Detailed calculations of this function are performed for the 2s _1/2 ??1s _1/2 transition in neutral hydrogen as well as Xe^53?+? and U^91?+? ions. The obtained results allow us to understand the influence of relativistic and non?Cdipole effects on the polarization correlations in the bound?Cbound two?Cphoton transitions in heavy ions.     

Study on the Absorption of 10TeV γ-Rays Interacting with Soft Photons in Intergalactic Space

TeV gamma rays will be attenuated or absorbed due to the interaction with soft photons in intergalactic space. The spectra of Mrk421 and Mrk501 during their flaring have been observed by ACTs. Using the data obtained with Tibet Ⅱ/HD AS array from October of 1995 to Augest of 1997,the preliminary results of energy density of intergalactic infrared radiation field are presented in this paper. Analysis shows that no statistically significant absorption evidence of high energy gamma rays is found up to around 30 TeV.     

Modified rate equation model including the photon�Cphoton resonance

We show that, when the longitudinal confinement factor in an edge-emitting laser is treated as a dynamic variable, the modulation transfer function has an extra term. This term produces a supplementary photon?Cphoton resonance peak in the modulation response at a frequency corresponding to the frequency separation between longitudinal modes, when these modes are phase-locked long enough (quasi-phase-locked). The photon?Cphoton resonance peak is strongest when two consecutive quasi-phase-locked dominant longitudinal modes have similar longitudinal envelopes and share equally the photon population.     

Magnetic-field influence on radiative axion decay into photons of the same polarization

The decays of a pseudoscalar particle, the axion, into two photons of the same polarization are studied in the model involving direct axion-electron coupling. These processes, which are forbidden in a vacuum because of a pseudoscalar nature of the axion, become possible in a magnetic field. It is shown that the kinematics of ultrarelativistic-axion decay substantially depends on photon polarizations. The probability of radiative axion decay in the limit of a strong magnetic field substantially exceeds the corresponding probability in a vacuum.     

Scalar glueball-q\bar{q} mixing above 1 GeV and implications for lattice QCD

Lattice QCD predictions have motivated several recent studies of the mixing between the predicted glueball and a nonet in the GeV region. We show that results from apparently different approaches have some common features, explain why this is so and abstract general conclusions. We place particular emphasis on the flavour dependent constraints imposed by decays of the , and to all pairs of pseudoscalar mesons. From these results we identify a systematic correlation between glueball mass, mixing, and flavour symmetry breaking and conclude that the glueball may be rather lighter than some quenched lattice QCD computations have suggested. We identify experimental tests that can determine the dynamics of a glueball in this mass region and discuss quantitatively the feasibility of decoding glueball- mixing. Received: 19 March 2001 / Published online: 17 August 2001     

Dust in the planetary system: Dust interactions in space plasmas of the solar system

Cosmic dust particles are small solid objects observed in the solar planetary system and in many astronomical objects like the surrounding of stars, the interstellar and even the intergalactic medium. In the solar system the dust is best observed and most often found within the region of the orbits of terrestrial planets where the dust interactions and dynamics are observed directly from spacecraft. Dust is observed in space near Earth and also enters the atmosphere of the Earth where it takes part in physical and chemical processes. Hence space offers a laboratory to study dust–plasma interactions and dust dynamics. A recent example is the observation of nanodust of sizes smaller than 10 nm. We outline the theoretical considerations on which our knowledge of dust electric charges in space plasmas are founded. We discuss the dynamics of the dust particles and show how the small charged particles are accelerated by the solar wind that carries a magnetic field. Finally, as examples for the space observation of cosmic dust interactions, we describe the first detection of fast nanodust in the solar wind near Earth orbit and the first bi-static observations of PMSE, the radar echoes that are observed in the Earth ionosphere in the presence of charged dust.     

Pseudoscalar-photon mixing and the large scale alignment of QSO optical polarizations

We review the observation of large scale alignment of QSO optical polarizations. Alignment is seen in patches of distance scale of order 1 Gpc. We argue that the existence of a hypothetical light pseudoscalar can explain these observations.     

Polarization interference of multi-wave mixing in a confined five-level system

We investigated the coexisting four-wave mixing, six-wave mixing and eight-wave mixing in ultra-thin, micrometer and long cells. Such multi-wave mixing (MWM) processes can be modified by the polarization interference. The degree of destructive interference of atomic polarizations can be controlled by the wave vector, dressing field and cell length. Specifically, the oscillation behavior of intensity and linewidth of MWM signal results from the destructive interference in ultra-thin cell. For a doubly-dressed four-wave mixing, the inner dressing field suppresses the destructive polarization interference in micrometer and long cells, induces resonance enhancement. However, the outer dressing field only enhances destructive interference.     

Polarization of four-wave mixing with electromagnetically induced transparency

The dependence of four-wave mixing (FWM) generated in Rubidium (Rb) vapor with electromagnetically induced transparency (EIT) window on polarizations of the incident fields is studied both theoretically and experimentally. The polarization properties of FWM signal under diverse laser polarization configurations are studied and compared. The results indicate that FWM signal is linear polarized when all incident fields are linear polarized. However, FWM becomes elliptical polarized if any incident field is elliptical polarized. Moreover, the polarizations of the incident fields also influence the dressing effect of the coupling field on FWM process. As the polarization of coupling field (or probe field) varying from linear to circular, the dressing effect gets stronger. By controlling the polarizations of the incident beams polarizations, we can manipulate the polarization state of FWM signal and the dressing effect as well.     

Flexible Manipulation of the Polarization Conversions in a Structured Vector Field in Free Space

The conversion between different polarizations generally requires an optical element or an optical system. We demonstrate, theoretically and experimentally, that the conversion between different states of polarization (SoP) can be flexibly manipulated in a structured optical field by itself. During the structured optical field propagation in free space, any two orthogonal polarizations can be generated and auto‐focus at any desired propagation positions by purposely designing the initial SoP distribution and a caustic phase in the field cross‐section. The experiment arrangement combines a caustic‐based approach and a 4f optical system. This approach provides a way to flexibly manipulate the polarization conversions in free space propagation by the optical field itself (without any physical element along the propagation path), may lead to more complex and flexible vectorial manipulations of an optical field scenarios and potential applications in corresponding areas.     

Weakly turbulent instability of anti-de Sitter spacetime

We study the nonlinear evolution of a weakly perturbed anti-de?Sitter (AdS) space by solving numerically the four-dimensional spherically symmetric Einstein-massless-scalar field equations with negative cosmological constant. Our results suggest that AdS space is unstable under arbitrarily small generic perturbations. We conjecture that this instability is triggered by a resonant mode mixing which gives rise to diffusion of energy from low to high frequencies.     

Coupled vortex oscillations in spatially separated permalloy squares

We experimentally study the magnetization dynamics of pairs of micron-sized permalloy squares coupled via their stray fields. The trajectories of the vortex cores in the Landau-domain patterns of the squares are mapped in real space using time-resolved scanning transmission x-ray microscopy. After excitation of one of the vortex cores with a short magnetic-field pulse, the system behaves like coupled harmonic oscillators. The coupling strength depends on the separation between the squares and the configuration of the vortex-core polarizations. Considering the excitation via a rotating in-plane magnetic field, it can be understood that only a weak response of the second vortex core is observed for equal core polarizations.     

The dynamical mixing of light and pseudoscalar fields

We solve the general problem of mixing of electromagnetic and scalar or pseudoscalar fields coupled by axion-type interactions L _int = g _ϕ ϕε _μναβ F ^μν F ^αβ . The problem depends on several dimensionful scales, including the magnitude and direction of background magnetic field, the pseudoscalar mass, plasma frequency, propagation frequency, wave number, and finally the pseudoscalar coupling. We apply the results to the first consistent calculations of the mixing of light propagating in a background magnetic field of varying directions, which show a great variety of fascinating resonant and polarization effects.      

Quark matter and meson properties in a Nonlocal SU(3) chiral quark model at finite temperature

We study the finite temperature behavior of light scalar and pseudoscalar meson properties in the context of a three-flavor nonlocal chiral quark model. The model includes mixing with active strangeness degrees of freedom, and takes care of the effect of gauge interactions by coupling the quarks with a background color field. We analyze the chiral restoration and deconfinement transitions, as well as the temperature dependence of meson masses, mixing angles, and decay constants.     

Heavy fermions in gauge theories: (I). Analysis of a general spinor loop

A general one-loop spinor diagram is analyzed in the coordinate space with an arbitrary number of external scalar, pseudoscalar, vector and axial vector legs. We identify chiral anomalies, and an unambiguous definition of a renormalized spinor loop amplitude in gauge theories is given by studying its symmetry properties. We then study the case when some of fermions carry very large masses compared to external momentum scales. Using a new calculational technique based on Schwinger's proper-time method, we provide the explicit forms of dominant effective local vertices induced by virtual heavy fermions in general spontaneously broken gauge theories. In the sequel to the present paper, these results will be applied to various interesting field theory models.     

Redshifts in space caused by stimulated Raman scattering in cold intergalactic Rydberg matter with experimental verification

The quantized redshifts observed from galaxies in the local supercluster have recently been shown to be well described by stimulated Stokes Raman processes in intergalactic Rydberg matter (RM). The size of the quanta corresponds to transitions in the planar clusters forming the RM, of the order of 6 × 10^?6 cm^?1. A stimulated Stokes Raman process gives redshifts that are independent of the wavelength of the radiation, and it allows the radiation to proceed without deflection, in agreement with observation. Such redshifts must also be additive during the passage through space. Rydberg matter is common in space and explains the observed Faraday rotation in intergalactic space and the spectroscopic signatures called unidentified infrared bands (UIBs) and diffuse interstellar bands (DIBs). Rydberg matter was also recently proposed to be baryonic dark matter. Experiments now show directly that IR light is redshifted by a Stokes stimulated Raman process in cold RM. Shifts of 0.02 cm^?1 are regularly observed. It is shown by detailed calculations based on the experimental results that the redshifts due to Stokes scattering are of at least the same magnitude as observations.     

Experimental consequences of a small mixture of cc̄ in the η′ and η mesons

We show that a small but significant mixing of η and η′ with the pseudoscalar cc? state may explanin the large η and η′ masses, the small mass of the new 2.8 GeV state, the large rates for ψ′ → ψη, ψ → η′γ and ψ → ηψ, the large number of photons in ψ decay, some of the missing decay modes of ψ′ and ψ and the small K/π ratio in ψ′ and ψ decays. We predict that 20–30% of all ψ and ψ′ decays contain an η′. Other tests and one important difficulty are also discussed.     

Spectrum of magnetohydrodynamic turbulence

We propose a phenomenological theory of strong incompressible magnetohydrodynamic turbulence in the presence of a strong large-scale external magnetic field. We argue that in the inertial range of scales, magnetic-field and velocity-field fluctuations tend to align the directions of their polarizations. However, the perfect alignment cannot be reached; it is precluded by the presence of a constant energy flux over scales. As a consequence, the directions of shear-Alfvén fluid and magnetic-field fluctuations at each scale lambda become effectively aligned within the angle phi(lambda) proportional to lambda (1/4), which leads to scale-dependent depletion of the nonlinear interaction and to the field-perpendicular energy spectrum E(k(perpendicular)) proportional to k(perpendicular)(-3/2). Our results may be universal, i.e., independent of the external magnetic field, since small-scale fluctuations locally experience a strong field produced by large-scale eddies.     

NEW MESON MASS RELATION AND LOWEST PSEUDOSCALAR GLUEBALL MASS

After considering its mixing with the glueball, we give a new mass relation for the meson nonet. According to this mass relation and the predicted mass of the pseudoscalar glueball given by lattice calculations and the effective Hamiltonian, the expected mass of the mixed pseudoscalar glueball is about 1.7 GeV. This result is helpful in the experimental search for the mixed isoscalar pseudoscalar glueball. η(1760) is discussed as a possible candidate for this type of particle.