We report a discovery of the circularly polarized CH A {sup 2}{Delta}-X {sup 2}{Pi} and B {sup 2}{Sigma}{sup -}-X {sup 2}{Pi} molecular bands in the spectrum of the DQ white dwarf (WD) GJ 841B. This ...is only the second such object since the discovery of G99-37 in the 1970s. GJ 841B is also the first WD to unambiguously show polarization in the C{sub 2} Swan bands. By modeling the intensity and circular polarization in the CH bands, we determine the longitudinal magnetic field strength of 1.3 {+-} 0.5 MG and the temperature of 6100 {+-} 200 K in the absorbing region. We also present new observations of G99-37 and obtain estimates of the magnetic field strength 7.3 {+-} 0.3 MG and temperature 6200 {+-} 200 K, in good agreement with previous results.
The paper presents theoretical calculations and experimental data on the permittivity of conductive porous acrylonitrile butadiene styrene. It is found that spectrum regions with differential ...absorption are caused by the volume resonance of electromagnetic waves inside pores and in the matrix material between them. Resonant frequencies with increased differential absorption can be controlled by changing the pore space, dimension, and matrix permittivity.
The process
is studied in the range of center-of-mass (c.m.) collision energies between 1.05 and 2.00 GeV on the basis of data corresponding to an integrated luminosity of 94.5 pb
that were ...accumulated in an experiment with the SND detector at the VEPP-2000
collider. The cross section for this process was measured for the first time and was found to receive a dominant contribution from the mechanism of a transition through an
intermediate state. The cross section measured for the process
agrees with the results of earlier measurements in the channel
. At a level of 5.7 standard deviations (5.7
), it is established that the process
is not fully described by hadronic intermediate states of the
type. The cross section was measured for this missing contribution, which may be generated by radiative processes—for example,
. It ranges from 15 to 20 pb over a broad energy interval extending from 1.3 to 1.9 GeV.
Recent results on
annihilation to hadrons below 2 GeV obtained at the SND experiment at the VEPP-2000 collider are presented. In particular, we discuss measurements of the
and
cross sections, and ...study of the processes
,
,
,
,
, and
.
The process
was studied in the energy range between 1 and 2 GeV to the best precision in the world. The data used correspond to an integrated luminosity of
accumulated with the SND detector at the ...VEPP-2000
collider. The statistical accuracy of the measured cross section is 2 to 22
, whereas the systematic uncertainty is 2.6 to 14
. The present results agree with the results of earlier measurements but have a better precision.
In an experiment with the SND detector at the VEPP-2000
collider, the cross sections for the processes
and
were measured at collision energies of
GeV in the center-of-mass frame. The results agree ...with the results of earlier measurements in the BABAR experiment and have a commensurate precision.
In the experiment with the SND detector at the VEPP-2000
collider, events of the process
were separated via measuring, in each counter of the multichannel calorimeter based on 1640 NaI(Tl) crystals, ...the time of delay of the signal from nonrelativistic antineutrons. The time resolution for events of the process
was 0.8 ns. The measured time spectrum of delays of the signal from antineutrons in the calorimeter at the c.m. energy of 1902 MeV agrees with the results of calculations.
Using the SND detector, the process
was studied in the energy range between 1.05 and 2.00 GeV. The respective measurement was performed on the basis of data accumulated in the experiments at the ...VEPP-2000 electron–positron collider throughout the runs of 2011 and 2012. Also, the invariant-mass spectra of the
and
combinations were analyzed in the energy range between 1.15 and 2 GeV. This resulted in finding an indication that the
excited state decayed predominantly through the
intermediate state.
Aims. We investigate the structure of the O-type binary system HD 48099 by measuring linear polarization that arises due to light scattering process. High-precison polarimetry provides independent ...estimates of the orbital parameters and gives important information on the properties of the system. Methods. Linear polarization measurements of HD 48099 in the B, V and R passbands with the high-precision Dipol-2 polarimeter have been carried out. The data have been obtained with the 60 cm KVA (Observatory Roque de los Muchachos, La Palma, Spain) and T60 (Haleakala, Hawaii, USA) remotely controlled telescopes during 31 observing nights. Polarimetry in the optical wavelengths has been complemented by observations in the X-rays with the Swift space observatory. Results. Optical polarimetry revealed small intrinsic polarization in HD 48099 with ~0.1% peak to peak variation over the orbital period of 3.08 d. The variability pattern is typical for binary systems, showing strong second harmonic of the orbital period. We apply our model code for the electron scattering in the circumstellar matter to put constraints on the system geometry. A good model fit is obtained for scattering of light on a cloud produced by the colliding stellar winds. The geometry of the cloud, with a broad distribution of scattering particles away from the orbital plane, helps in constraining the (low) orbital inclination. We derive from the polarization data the inclination i = 17° ± 2° and the longitude of the ascending node Ω = 82° ± 1° of the binary orbit. The available X-ray data provide additional evidence for the existence of the colliding stellar winds in the system. Another possible source of the polarized light could be scattering from the stellar photospheres. The models with circumstellar envelopes, or matter confined to the orbital plane, do not provide good constraints on the low inclination, better than i ≤ 27°, as is already suggested by the absence of eclipses.
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