Behaviour of the Blazar CTA 102 during two giant outbursts

Blazar CTA 102 underwent exceptional optical and high-energy outbursts in 2012 and 2016-2017. We analyze its behaviour during these events, focusing on polarimetry as a tool that allows us to trace changes in the physical conditions and geometric configuration of the emission source close to the central black hole. We also use Fermi gamma-ray data in conjunction with optical photometry in an effort to localize the origin of the outbursts.AST-1615796 - Boston Universit

On the estimate of the sigma^(I = 1)_(KN)(0)-term value from the energy level shift of kaonic hydrogen in the ground state

Using the experimental data on the energy level shift of kaonic hydrogen in the ground state (the DEAR Collaboration, Phys. Rev. Lett. 94, 212302 (2005)) and the theoretical value of the energy level shift, calculated within the phenomenological quantum field theoretic approach to the description of strong low-energy anti-K N and anti-K NN interactions developed at Stefan Meyer Institut fuer subatomare Physik in Vienna, we estimate the value of the sigma^(I = 1)_(KN)(0)-term of low-energy anti-K N scattering. We get sigma^(I = 1)_(KN)(0) = (433 +/- 85) MeV. This testifies the absence of strange quarks in the proton structure.Comment: 7 pages, no figure

On the influence of the magnetic field of the GSI experimental storage ring on the time-modulation of the EC-decay rates of the H-like mother ions

We investigate the influence of the magnetic field of the Experimental storage ring (ESR) at GSI on the periodic time-dependence of the orbital K-shell electron capture decay $(EC$) rates of the H--like heavy ions. We approximate the magnetic field of the ESR by a uniform magnetic field. Unlike the assertion by Lambiase et al., arXiv: 0811.2302 [nucl-th], we show that a motion of the H-like heavy ion in a uniform magnetic field cannot be the origin of the periodic time-dependence of the EC-decay rates of the H-like heavy ions.Comment: 3 pages, 1 figur

Energy Level Displacement of Excited np State of Kaonic Deuterium In Faddeev Equation Approach

We calculate the energy level displacement of the excited $np$ state of kaonic deuterium in terms of the P-wave scattering length of $K^-d$ scattering. We solve the Faddeev equations for the amplitude of $K^-d$ scattering in the fixed centre approximation and derive the complex P-wave scattering length of $K^-d$ scattering in terms of the S-wave and P-wave scattering lengths of $\bar{K}N$ scattering. The estimated uncertainty of the complex P-wave scattering length is of about $15\,$. For the calculated width $\Gamma_{2p} = 10.203\,{\rm meV}$ of the excited $2p$ state of kaonic deuterium we evaluate the yield $Y_{K^-d} = 0.27\,$ of $X$-rays for the $K_{\alpha}$ emission line of kaonic deuterium. Using the complex S-wave and P-wave scattering lengths of $\bar{K}N$ scattering, calculated in \cite{ECL1,Weise1}, we get the width $\Gamma_{2p} = 2.675\,{\rm meV}$ of the excited $2p$ state and the yield $Y_{K^-d} = 1.90 \,$ of $X$-rays for the $K_{\alpha}$ emission line of kaonic deuterium. The results, obtained in this paper, can be used for the planning of experiments on the measurements of the energy level displacement of the ground state of kaonic deuterium, caused by strong low-energy interactions.Comment: 13 page

On the S-wave piD-scattering length in the relativistic field theory model of the deuteron

The S-wave scattering length of the strong pion-deuteron (pi D) scattering is calculated in the relativistic field theory model of the deuteron suggested in [1,2].The theoretical result agrees well with the experimental data. The important role of the Delta-resonance contribution to the elastic pi D-scattering is confirmed.Comment: 7 pages, no figures, accepted for publication in Z. Phys.

On radiative np -> 1s + gamma transitions, induced by strong low-energy interactions,in kaonic atoms

We calculate the rates of the radiative transitions np -> 1s + gamma in kaonic hydrogen and kaonic deuterium, induced by strong low-energy interactions and enhanced by Coulomb interactions. The obtained results should be taken into account for the theoretical analysis of the experimental data on the X-ray spectra and yields in kaonic atoms.Comment: 10 pages, 1 figur

On the polarization properties of the charmed baryon Lambda^+_c in the Lambda^+_c -> p + K^- + pi^+ + pi^0 decay

The polarization properties of the charmed Lambda^+_c baryon are investigated in weak non-leptonic four-body Lambda^+_c -> p + K^- + pi^+ + pi^0 decay. The probability of this decay and the angular distribution of the probability are calculated in the effective quark model with chiral U(3)XU(3) symmetry incorporating Heavy Quark Effective theory (HQET) and the extended Nambu-Jona-Lasinio model with a linear realization of chiral U(3)XU(3) symmetry. The theoretical value of the probability of the decay Lambda^+_c -> p + K^- + pi^+ + pi^0 relative to the probability of the decay Lambda^+_c -> p + K^- + pi^+ does not contain free parameters and fits well experimental data. The application of the obtained results to the analysis of the polarization of the Lambda^+_c produced in the processes of photo and hadroproduction is discussed.Comment: 10 pages, no figures, Late

Dissecting the long-term emission behaviour of the BL Lac object Mrk 421

We report on long-term multiwavelengthmonitoring of blazar Mrk 421 by the GLAST-AGILE Support Program of the Whole Earth Blazar Telescope (GASP-WEBT) collaboration and Steward Observatory, and by the Swift and Fermi satellites. We study the source behaviour in the period 2007–2015, characterized by several extreme flares. The ratio between the optical, X-ray and γ -ray fluxes is very variable. The γ -ray flux variations show a fair correlation with the optical ones starting from 2012.We analyse spectropolarimetric data and find wavelengthdependence of the polarization degree (P), which is compatible with the presence of the host galaxy, and no wavelength dependence of the electric vector polarization angle (EVPA). Optical polarimetry shows a lack of simple correlation between P and flux and wide rotations of the EVPA.We build broad-band spectral energy distributions with simultaneous near-infrared and optical data from the GASP-WEBT and ultraviolet and X-ray data from the Swift satellite. They show strong variability in both flux and X-ray spectral shape and suggest a shift of the synchrotron peak up to a factor of ∼50 in frequency. The interpretation of the flux and spectral variability is compatible with jet models including at least two emitting regions that can change their orientation with respect to the line of sight.http://10.0.4.69/mnras/stx2185Accepted manuscrip