119247194
ON THE NATURE OF THE PROGENITOR OF THE Type Ia SN2011fe IN M101
The explosion of a Type Ia supernova, SN2011fe, in the nearby Pinwheel galaxy (M101 at 6.4 Mpc) provides an opportunity to study pre-explosion images and search for the progenitor, which should consist of a white dwarf (WD), possibly surrounded by an accretion disk, in orbit with another star. We report on our use of deep Chandra observations and Hubble Space Telescope observations to limit the luminosity and temperature of the pre-explosion WD. It is found that if the spectrum was a blackbody, then pre-SN WDs with steady nuclear burning of the highest possible temperatures and luminosities are excluded assuming moderate n{sub H} values, but values of kT between roughly 10 eV and 60 eV are permitted even if the WD was emitting at the Eddington luminosity. This allows the progenitor to be an accreting nuclear-burning WD with an expanded photosphere 4-100 times the WD itself, or a super-critically accreting WD blowing off an optically thick strong wind, or possibly a recurrent nova with luminosities an order of magnitude lower than Eddington. The observations are also consistent with a double degenerate scenario, or a spinning down WD that has been spun up by accretion from the donor.
119218213
Four IRAC Sources with an Extremely Red H – [3.6] Color: Passive or Dusty Galaxies at z > 4.5?
We report the detection of four IRAC sources in the GOODS-South field with an extremely red color of H - [3.6] > 4.5. The four sources are not detected in the deep Hubble Space Telescope WFC3 H-band image with H-limit = 28.3 mag. We find that only three types of SED templates can produce such a red H -[3.6] color: a very dusty SED with the Calzetti extinction of A(V) = 16 mag at z = 0.8; a very dusty SED with the SMC extinction of AV = 8 mag at z = 2.0-2.2; and an 1 Gyr SSP with A(V) similar to 0.8 at z = 5.7. We argue that these sources are unlikely dusty galaxies at z 4.5 remains a possible solution for the 4 sources. At z > 4.5, these sources have stellar masses of log(M-*/M-circle dot) = 10.6-11.2. One source, ERS-1, is also a type-II X-ray QSO with L2-8 (keV) = 1.6 x 10(44) er gs(-1). One of the four sources is an X-ray QSO and another one is a HyperLIRG, suggesting a galaxy-merging scenario for the formation of these massive galaxies at high redshifts.
123145784
OZI-ALLOWED TWO BODY ϒ DECAYS IN THE 3P0 MODEL WITH THE RELATIVISTIC WAVE FUNCTIONS
We combine the Bethe–Salpeter method with the 3P0 model to describe OZI-allowed two body meson decays. In this combined method, the relativistic wave functions defined in the Salpeter equation show up in the decay amplitude of the 3P0 model automatically. We apply the method to OZI-allowed ϒ(4S, 5S, 6S) two body decays. The results are roughly consistent with the experimental data and the predictions of ϒ(6S) decays are given.
119181798
Radiative E1 decays of X(3872)
Abstract Radiative E1 decay widths of X ( 3872 ) are calculated through the relativistic Salpeter method, with the assumption that X ( 3872 ) is the χ c 1 ( 2 P ) state, which is the radial excited state of χ c 1 ( 1 P ) . We first calculated the E1 decay width of χ c 1 ( 1 P ) . The result is in agreement with experimental data excellently. Then we calculated the width of X ( 3872 ) with the assignment χ c 1 ( 2 P ) . Results are: Γ ( X ( 3872 ) → γ J / ψ ) = 33.0 keV , Γ ( X ( 3872 ) → γ ψ ( 2 S ) ) = 146 keV and Γ ( X ( 3872 ) → γ ψ ( 3770 ) ) = 7.09 keV . The ratio Br ( X ( 3872 ) → γ ψ ( 2 S ) ) / Br ( X ( 3872 ) → γ J / ψ ) = 4.4 agrees with experimental data by BaBar, but is larger than the new up-bound reported by Belle recently. With the same method, we also predicted the decay widths, Γ ( χ b 1 ( 1 P ) ) → γ ϒ ( 1 S ) = 30.0 keV , Γ ( χ b 1 ( 2 P ) ) → γ ϒ ( 1 S ) = 5.65 keV and Γ ( χ b 1 ( 2 P ) ) → γ ϒ ( 2 S ) = 15.8 keV , from which we get the full widths: Γ ( χ b 1 ( 1 P ) ) ∼ 85.7 keV and Γ ( χ b 1 ( 2 P ) ) ∼ 66.5 keV .
118367171
Static Solutions with Spherical Symmetry in f(T) Theories
The spherically symmetric static solutions are searched for in some f(T) models of gravity theory with a Maxwell term. To do this, we demonstrate that reconstructing the Lagrangian of f(T) theories is sensitive to the choice of frame, and then we introduce a particular frame based on the conformally Cartesian coordinates. In this particular frame, the existence conditions of various solutions are presented. Our results imply that only a limited class of f(T) models can be solved in this frame. For more general models, the search for spherically symmetric static solutions is still an open and challenging problem, hopefully solvable in other frames.
117931252
The Properties of $D^{*}_{s1}(2700)^{+}$
The new particle $D^{*}_{s1}(2700)^{+}$ has stimulated many attentions. There are different assignments of its inherent properties. It may be a $2^3S_1$, $1^3D_1$ or the mixture of $2^3S_1-1^3D_1$ $c\bar s$ $1^-$ state. By considering its mass, decay modes, full width, production rate, and comparing with current experimental data, we point out that there is another more reasonable assignment: $D^{*}_{s1}(2700)^{+}$ could be identified as two resonances, one of which is a $2^3S_1$ state, another is a 1D state, and both are $c\bar s$ $1^-$ states. The two states have very close masses, which are around 2700 MeV, and both have broad decay widths. So in experiments, the overlapping of $DK$ or $D^*K$ invariant mass distribution coming from their decays is found, but the current experiments could not distinguish these two resonances and reported one particle.
118390460
1/R correction to gravity in the early universe
To explain the accelerated expansion of the late universe, the 1/R correction to Einstein gravity is usually considered, where R is the Ricci scalar. This correction term, if stable, is generally believed to be negligible during inflation. However, if the 1/R term is inflaton dependent, it will dramatically change the story of inflation. The entropy perturbation will naturally appear and drive the evolution of curvature perturbation outside the Hubble horizon. In a large class of models, the entropy perturbation can be made nearly scale invariant. In Einstein gravity the single-field inflation with a quartic potential has been ruled out by recent observations, but it revives when the 1/R term is turned on. The evolution of non-Gaussianities on a large scale are also studied and applied to inflation with 1/R correction. In some specific models, a large non-Gaussianity can be naturally generated outside the horizon. A recent study ruled out almost all f(R) models during the matter-dominated phase. Taking this into consideration, we are left with a limited class of model which recovers the Einstein gravity soon after reheating.