Abstract:
The surprising thing is that arising almost 50 years ago from the linear sigma model (LSM) with spontaneously broken chiral symmetry, the light scalar meson problem has become central in the nonperturbative quantum chromodynamics (QCD) for it has been made clear that LSM could be the low energy realization of QCD. First we review briefly signs of four-quark nature of light scalars. Then we show that the light scalars are produced in the two photon collisions via four-quark transitions in contrast to the classic $P$ wave tensor $q\bar q$ mesons that are produced via two-quark transitions $\gamma\gamma\to q\bar q$. Thus we get new evidence of the four-quark nature of these states.

Abstract:
The surprising thing is that the light scalar meson problem, arising 50 years ago from the linear sigma model (LSM) with spontaneously broken chiral symmetry, has become central in the nonperturbative quantum chromodynamics (QCD), because it has been made clear that LSM could be the low energy realization of QCD. First, we review briefly signs of four-quark nature of light scalars. Then we show that the light scalars are produced in the two-photon collisions via four-quark transitions in contrast to the classic P wave tensor q\bar q mesons that are produced via two-quark transitions \gamma\gamma->q\bar q. Thus we get new evidence of the four-quark nature of the lower scalar states.

Abstract:
New high-statistics Belle data on the reaction \gamma\gamma\to\pi^0\eta are analyzed to clarify the two-photon production mechanisms and the nature of the a_0(980) meson. The obtained solution for the amplitude \gamma\gamma\to\pi^0\eta is consistent with the chiral theory expectation for the \pi\eta scattering length, with the strong coupling of the a_0(980) to the \pi\eta, K\bar K, and \pi\eta' channels, and with a key role of the rescattering mechanisms a_0(980)\to(K\bar K+ \pi^0\eta+\pi^0\eta')\to\gamma\gamma in the a_0(980)\to\gamma\gamma decay. Such a picture argues in favor of the q^2\bar q^2 nature of the a_0(980) meson and is in agreement with the properties of its partners, the \sigma_0(600) and f_0(980) mesons, in particular, with those that manifest themselves in \gamma\gamma\to\pi\pi. An important role of the vector meson exchanges in the formation of the nonresonant background in \gamma\gamma\to\pi^0\eta is also revealed. The preliminary information on the reaction \pi^0\eta\to\pi^0\eta is obtained.

Abstract:
We report the observation of an anomalous antibunching dip in intensity autocorrelation function with photon correlation measurements on a single-photon emitter (SPE). We show that the anomalous dip observed is a manifestation of quantum nature of SPEs. Taking population dynamics in a quantum two-level system into account correctly, we redefine intensity autocorrelation function. This is of primary importance for precisely evaluating the lowest-level probability of multiphoton generation in SPEs toward realizing versatile pure SPEs for quantum information and communication.

Abstract:
We demonstrate and study the enhancement of intermediate-field two-photon absorption by shaped femtosecond pulses having spectral phases of antisymmetric nature. The intermediate-field regime corresponds to pulse intensities, where the two-photon absorption is coherently induced by the weak-field nonresonant two-photon transitions as well as by additional resonance-mediated four-photon transitions. It is a regime of significant excitation yields, exceeding the weak-field yields by two orders of magnitudes, reaching about 10-20% population transfer. The considered antisymmetric nature is with respect to one-half of the (initial-to-final) two-photon transition frequency. The corresponding pulse spectrum is detuned from this frequency (the detuning direction is according to the system). We study in detail the coherent interference mechanism leading to the observed enhancement using forth-order frequency-domain perturbative analysis. We also show that, even though the maximal enhancement is achieved with phase patterns of perfect antisymmetry, at high enough intermediate-field intensities absorption enhancement beyond the transform-limited level is still achievable even with patterns having some degree of deviation from perfect antisymmetry. The degree of tolerance to deviations from perfect antisymmetry increases as the pulse intensity increases. The theoretical and experimental model system of the study is atomic sodium. These findings are of particular importance for coherent control scenarios that simultaneously involve multiple excitation channels.

Abstract:
The present study intends: on the one hand, to give an explanation of the origin and the nature of the elementary electric charge (e-), by determining the most possible reason why the electron shows Coulomb field, and by finding the mechanic equivalent to the electric charge; and on the other hand, to suggest a possible size for the photon by comparing maximum power wave lengths of photons and particles, taking into consideration the Planck length.The initial idea arose from a previous paper of the author [1] entitled “Dwarf Primary Black Holes and Nucleons – Indirect Theory of Unified Fields – Relation between Gravitational and Nuclear Potentials”, where a new transformation formula of a collapsing mass and its reverse formula are introduced. From the application of the reverse formula, we conclude that electrons and nucleons (from quarks) were created from the crash of initial (primary) matter of the Universe, 9.11 millions and 1.674 billions of tons respectively, in the first infinitesimal flashes just after the Big Bang.Moreover, it is proved that: a) the nuclear forces of the nucleons come from the gravitational potential of their initial mass that is stored in them, b) the velocity of the collapse (crash) of a mass increases vertically, when its volume gets a critical value (critical volume), c) the gravity radius of the particle’s initial mass is smaller or equal to the radius of the critical volume and the two radii take the same value, when the radius of the particle concurs with the gravity radius of the particle’s mass and d) when the final velocity of collapse is equal to the velocity of light, then the collapsing mass changes into antimass (antimatter)

Abstract:
Nature. Le monde bio-physique, pour autant qu’il concerne la société. La nature est l’ensemble des phénomènes, des connaissances, des discours et des pratiques résultant d’un processus sélectif d’incorporation des processus physiques et biologiques par la société. Bien loin d’être une instance extérieure à la société, un système autonome, la nature est une construction sociale, et elle se trouve intégrée, sous différents aspects, dans le moindre objet de société et ...

Abstract:
Calculations of cross-sections for the gluon-photon production of $B_c$ and $B_c^*$ mesons as well as for the production in $ep$-interactions at HERA are performed in the leading order of perturbative QCD. We show that the nonabelian structure of QCD leads to an essential forward-backward asymmetry in these processes.

Abstract:
The RT-2 Experiment, a low energy gamma-ray telescope, onboard CORONAS-PHOTON satellite is designed to study the temporal, spectral and spatial properties of the hard X-ray solar flares mainly in the energy range of 15 - 100 keV, which is extendable upto 1000 keV. During the operational period of ~ 9 months, it has been able to detect a few solar flares and at least four Gamma-Ray Bursts (GRBs). In this paper, we discuss the properties of the GRBs as observed by RT-2 in the energy band of 15 to ~ 1000 keV. We will present the results of spectral and timing properties of the GRBs (specially for the GRB 090618) using RT-2 detectors. Temporal analysis suggests that all four GRBs belong to the category of long duration bursts.

Abstract:
We present an analysis of the X-ray spectral properties observed from black hole candidate (BHC) binary SS~433. We have analyzed RXTE data from this source, coordinated with Green Bank Interferometer/RATAN-600. We show that SS~433 undergoes a X-ray spectral transition from the low hard state (LHS) to the intermediate state (IS). We show that the X-ray broad-band energy spectra during all spectral states are well fit by a sum of so called ``Bulk Motion Comptonization (BMC) component'' and by two (broad and narrow) Gaussians for the continuum and line emissions respectively. In addition to these spectral model components we also find a strong feature that we identify as a "blackbody-like (BB)" component which color temperature is in the range of 4-5 keV in 24 IS spectra during the radio outburst decay in SS~433. Our observational results on the "high temperature BB" bump leads us to suggest the presence of gravitationally redshifted annihilation line emission in this source. I\ We have also established the photon index saturation at about 2.3 in index vs mass accretion correlation. This index-mass accretion correlation allows us to evaluate the low limit of black hole (BH) mass of compact object in SS~433, M_{bh}> 2 solar masses, using the scaling method using BHC GX 339-4 as a reference source. Our estimate of the BH mass in SS 433 is consistent with recent BH mass measurement using the radial-velocity measurements of the binary system by Hillwig & Gies who find that M_{x}=(4.3+/-0.8 solar masses. This is the smallest BH mass found up to now among all BH sources. Moreover, the index saturation effect versus mass accretion rate revealed in SS~433, like in a number of other BH candidates, is the strong observational evidence for the presence of a BH in SS~433.