We present the first Bayesian method for tomographic decomposition of the plane-of-sky orientation of the magnetic field with the use of stellar polarimetry and distance. This standalone tomographic ...inversion method presents an important step forward in reconstructing the magnetized interstellar medium (ISM) in 3D within dusty regions. We develop a model in which the polarization signal from the magnetized and dusty ISM is described by thin layers at various distances. Our modeling makes it possible to infer the mean polarization (amplitude and orientation) induced by individual dusty clouds and to account for the turbulence-induced scatter in a generic way. We present a likelihood function that explicitly accounts for uncertainties in polarization and parallax. We develop a framework for reconstructing the magnetized ISM through the maximization of the log-likelihood using a nested sampling method. We test our Bayesian inversion method on mock data taking into account realistic uncertainties from Gaia and as expected for the optical polarization survey PASIPHAE according to the currently planned observing strategy. We demonstrate that our method is effective at recovering the cloud properties as soon as the polarization induced by a cloud to its background stars is higher than \(\sim 0.1\%\) for the adopted survey exposure time and level of systematic uncertainty. Our method makes it possible to recover not only the mean polarization properties but also to characterize the intrinsic scatter, thus creating new ways to characterize ISM turbulence and the magnetic field strength. Finally, we apply our method to an existing data set of starlight polarization with known line-of-sight decomposition, demonstrating agreement with previous results and an improved quantification of uncertainties in cloud properties.
The symmetries of the tree level string effective action are discussed. An appropriate effective action is constructed starting from the manifestly SL(2,R) invarint form of string effective action ...introduced by Schwarz and Sen. The conserved charges are derived and generators of infinitesimal transformations are obtained in the Hamiltonian formalism. Some interesting consequences of the canonical transformations are explored.
We measure the $B^0$ lifetime and flavor-oscillation frequency using $B^0\to
D^{(*)-}\pi^+$ decays collected by the Belle II experiment in asymmetric-energy
$e^+e^-$ collisions produced by the ...SuperKEKB collider operating at the
$\Upsilon(4S)$ resonance. We fit the decay-time distribution of signal decays,
where the initial flavor is determined by identifying the flavor of the other
$B$ meson in the event. The results, based on $33000$ signal decays
reconstructed in a data sample corresponding to ${190}\text{fb}^{-1}$, are
$\tau_{B^0} = {1.499}\pm{0.013}\pm{0.008}\;\text{ps}$, $\Delta m_d =
{0.516}\pm{0.008}\pm{0.005}\;\text{ps}^{-1}$, where the first uncertainties are
statistical and the second are systematic. These results are consistent with
the world-average values.
We report a measurement of the mixing-induced and direct $\textit{CP}$
violation parameters $S_{\text{CP}}$ and $A_{\text{CP}}$ from $B^0 \to J/\psi
K^0_S$ decays reconstructed by the Belle II ...experiment at the SuperKEKB
asymmetric-energy electron-positron collider. The data, collected at the
center-of-mass energy of the $\Upsilon(4S)$ resonance, correspond to
$190\text{fb}^{-1}$ of integrated luminosity. We measure ${S_{\text{CP}} =
0.720\pm0.062\pm0.016}$ and $A_{\text{CP}} = 0.094\pm0.044^{+0.042}_{-0.017}$,
where the first uncertainties are statistical and the second systematic. In the
Standard Model, $S_{\text{CP}}$ equals $\sin(2\phi_1)$ to a good approximation.
The
S-duality invariance of the equations of motion of four dimensional string effective action with cosmological constant, Λ, is studied. It is demonstrated that the
S-duality symmetry of the field ...equations are broken for nonzero Λ. The “naturalness” hypothesis is invoked to argue that Λ should remain small since exact
S-duality symmetry will force the cosmological constant to vanish in the string effective action.
The Wess–Zumino term and quantum tunneling Liang, J.-Q.; Maharana, L.; Müller-Kirsten, H.J.W.
Physica. B, Condensed matter,
11/1999, Letnik:
271, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The significance of the Wess–Zumino term in spin tunneling is explored, and a formula is established for the splitting of energy levels of a particle with large fermionic spin as an applied magnetic ...field is switched on.
We present the design and performance of RoboPol, a four-channel optical polarimeter operating at the Skinakas Observatory in Crete, Greece. RoboPol is capable of measuring both relative linear ...Stokes parameters \(q\) and \(u\) (and the total intensity \(I\)) in one sky exposure. Though primarily used to measure the polarization of point sources in the R-band, the instrument features additional filters (B, V and I), enabling multi-wavelength imaging polarimetry over a large field of view (13.6' \(\times\) 13.6'). We demonstrate the accuracy and stability of the instrument throughout its five years of operation. Best performance is achieved within the central region of the field of view and in the R band. For such measurements the systematic uncertainty is below 0.1% in fractional linear polarization, \(p\) (0.05% maximum likelihood). Throughout all observing seasons the instrumental polarization varies within 0.1% in \(p\) and within 1\(^\circ\) in polarization angle.
COMPLETE is a flagship mission concept combining broadband spectroscopic imaging and comprehensive magnetography from multiple viewpoints around the Sun to enable tomographic reconstruction of 3D ...coronal magnetic fields and associated dynamic plasma properties, which provide direct diagnostics of energy release. COMPLETE re-imagines the paradigm for solar remote-sensing observations through purposefully cooptimized detectors distributed on multiple spacecraft that operate as a single observatory, linked by a comprehensive data/model assimilation strategy to unify individual observations into a single physical framework. We describe COMPLETE's science goals, instruments, and mission implementation. With targeted investment by NASA, COMPLETE is feasible for launch in 2032 to observe around the maximum of Solar Cycle 26.
Phys.Lett. B408 (1997) 164-172 The ten-dimensional type IIA string effective action with cosmological
constant term is dimensionally reduced on a d-dimensional torus to derive lower
dimensional ...effective action. The symmetries of the reduced effective action
are examined. It is shown that the resulting six-dimensional theory does not
remain invariant under $SO(4,4)$ symmetry whereas the reduced action, in the
absence of the cosmological constant respects the symmetry as was shown by Sen
and Vafa. New class of black hole solutions are obtained in five and four
dimensions in the presence of cosmological constant. For the six-dimensional
theory, a four-brane solution is also presented.
Phys.Lett. B380 (1996) 280-285 The symmetries of the tree level string effective action are discussed. An
appropriate effective action is constructed starting from the manifestly
SL(2,R) invarint ...form of string effective action introduced by Schwarz and Sen.
The conserved charges are derived and generators of infinitesimal
transformations are obtained in the Hamiltonian formalism. Some interesting
consequences of the canonical transformations are explored.
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