971 research outputs found

    TYC 1031 01262 1: The First Known Galactic Eclipsing Binary with a Type II Cepheid Component

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    We present the discovery and CCD observations of the first eclipsing binary with a Type II Cepheid component in our Galaxy. The pulsation and orbital periods are found to be 4.1523 and 51.38 days, respectively, i.e. this variable is a system with the shortest orbital period among known Cepheid binaries. Pulsations dominate the brightness variations. The eclipses are assumed to be partial. The EB-subtype eclipsing light curve permits to believe that the binary's components are non-spherical.Comment: 3 pages, 3 figures, accepted to MNRAS Letter

    T-odd correlations from CP violating anomalous top-quark couplings revisited

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    We revisit the effect of CP violating anomalous top-quark couplings in ttˉt\bar{t} production and decay. We consider ttˉt\bar{t} production through gluon fusion (and light qqˉq{\bar q} annihilation) followed by top-quark decay into bWbW or bνb\ell\nu. We find explicit analytic expressions for all the triple products generated by the anomalous couplings that fully incorporate all spin correlations. Our results serve as a starting point for numerical simulations for the LHC.Comment: minor typos correcte

    A Perturbative Realization of Miransky Scaling

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    Near conformal dynamics is employed in different extensions of the standard model of particle interactions as well as in cosmology. Many of its interesting properties are either conjectured or determined using model computations. We introduce a relevant four dimensional gauge theory template allowing us to investigate such dynamics perturbatively. The gauge theory we consider is quantum chromodynamics with the addition of a meson-like scalar degree of freedom as well as an adjoint Weyl fermion. At the two-loop level, and in the Veneziano limit, we firmly establish the existence of several fixed points of which one is all directions stable in the infrared. An interesting feature of the model is that this fixed point is lost, within the perturbatively trustable regime, by merging with another fixed point when varying the number of quark flavors. We show the emergence of the Miransky scaling and determine its properties. We are also able to determine the walking region of the theory which turns out to be, at large number of colors, about 12% of the conformal window. Furthermore, we determine highly relevant quantities for near conformal dynamics such as the anomalous dimension of the fermion masses.Comment: 17 pages, 8 figure

    Emergence of supersymmetry on the surface of three dimensional topological insulators

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    We propose two possible experimental realizations of a 2+1 dimensional spacetime supersymmetry at a quantum critical point on the surface of three dimensional topological insulators. The quantum critical point between the semi-metallic state with one Dirac fermion and the s-wave superconducting state on the surface is described by a supersymmetric conformal field theory within ϵ\epsilon-expansion. We predict the exact voltage dependence of the differential conductance at the supersymmetric critical point.Comment: 8 pages, 2 figures; published versio

    THIACALIX[4]ARENES DERIVATIVES: FROM SELF-ASSEMBY TO FUNCTIONAL MATERIALS

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    This work was supported by the by Russian Science Foundation, project # 19-13-00095

    Cross-relaxation and phonon bottleneck effects on magnetization dynamics in LiYF4:Ho3+

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    Frequency and dc magnetic field dependences of dynamic susceptibility in diluted paramagnets LiYF4_4:Ho3+^{3+} have been measured at liquid helium temperatures in the ac and dc magnetic fields parallel to the symmetry axis of a tetragonal crystal lattice. Experimental data are analyzed in the framework of microscopic theory of relaxation rates in the manifold of 24 electron-nuclear sublevels of the lowest non-Kramers doublet and the first excited singlet in the Ho3+^{3+} ground multiplet 5I8^5I_8 split by the crystal field of S4_4 symmetry. The one-phonon transition probabilities were computed using electron-phonon coupling constants calculated in the framework of exchange charge model and were checked by optical piezospectroscopic measurements. The specific features observed in field dependences of the in- and out-of-phase susceptibilities (humps and dips, respectively) at the crossings (anti-crossings) of the electron-nuclear sublevels are well reproduced by simulations when the phonon bottleneck effect and the cross-spin relaxation are taken into account
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