Studying newborn neutron stars by the transient emission after stellar collapses and compact binary mergers

The formation of neutron stars (NSs), both from collapses of massive stars and mergers of compact objects, can be usually indicated by bright transients emitted from explosively-ejected material. In particular, if the newborn NSs can rotate at a millisecond period and have a sufficiently high magnetic field, then the spin-down of the NSs would provide a remarkable amount of energy to the emitting material. As a result, super-luminous supernovae could be produced in the massive stellar collapse cases, while some unusual fast evolving and luminous optical transients could arise from the cases of NS mergers and accretion-induced collapses of white dwarfs. In all cases, if the dipolar magnetic fields of the newborn NSs can be amplified to be as high as $10^{15}$ G, a relativistic jet could be launched and then a gamma-ray burst can be produced as the jet successfully breaks out from the surrounding nearly-isotropic ejected material.Comment: 10 pages, 9 pictures, to appear in the AIP Proceedings of the Xiamen-CUSTIPEN Workshop on the EOS of Dense Neutron-Rich Matter in the Era of Gravitational Wave Astronomy, Jan. 3-7, Xiamen, Chin

The transition form factors and angular distributions of the Λb→Λ(1520)(→NKˉ)ℓ+ℓ−\bm{\Lambda_b\to\Lambda(1520)(\to N\bar{K})\ell^+\ell^-} decay supported by baryon spectroscopy

We calculate the weak transition form factors of the $\Lambda_b\to\Lambda(1520)$ transition, and further calculate the angular distributions of the rare decays $\Lambda_b\to\Lambda(1520)(\to N\bar{K})\ell^{+}\ell^{-}$ ($N\bar{K}=\{pK^-,n\bar{K}^0\}$) with unpolarized $\Lambda_b$ and massive leptons. The form factors are calculated by the three-body light-front quark model with the support of numerical wave functions of $\Lambda_b$ and $\Lambda(1520)$ from solving the semirelativistic potential model associated with the Gaussian expansion method. By fitting the mass spectrum of the observed single bottom and charmed baryons, the parameters of the potential model are fixed, so this strategy can avoid the uncertainties arising from the choice of a simple harmonic oscillator (SHO) wave function of the baryons. With more data accumulated in the LHCb experiment, our result can help for exploring the $\Lambda_b\to\Lambda(1520)\ell^+\ell^-$ decay and deepen our understanding on the $b\to s\ell^+\ell^-$ processes.Comment: 21 pages, 9 figures. Accepted by Phys. Rev.

2-(4-Isopropyl-4-methyl-5-oxo-4,5-dihydro-1H-imidazol-2-yl)-5-methyl­nicotinic acid

In the title herbicideh/phytocide, known as imaza­pic, C14H17N3O3, the pyridine and imidazole rings are almost coplanar [dihedral angle = 3.08 (5)°]. An intra­molecular O—H⋯N hydrogen bond occurs. In the crystal, an N—H⋯O hydrogen bond links mol­ecules into a chain parallel to [010]

[μ-4-Benzoyl-1-(1-oxido-2-naphthyl­carbon­yl)thio­semicarbazidato(4−)]bis­[pyridine­copper(II)]

In the title dinuclear complex, [Cu2(C19H11N3O3S)(C5H5N)2], the two CuII centers have different coordination environments, viz. N2OS and N2O2, each exhibiting a distorted square-planar geometry. π–π inter­actions between the aromatic rings of neighbouring complexes [centroid–centroid distance = 3.856 (5) Å] link pairs of mol­ecules into centrosymmetric dimers, which are further packed into stacks along the b axis with relatively short Cu⋯Cu separations of 3.482 (1) Å. Weak inter­molecular C—H⋯N hydrogen bonds help to consolidate the crystal packing

1,4-Bis(4-pyridylmeth­oxy)benzene

The mol­ecule of the title compound, C18H16N2O2, lies about a center of inversion. The central phenyl­ene ring is aligned at 62.7 (1)° with respect to the pyridyl ring. In the crystal, weak inter­molecular C—H⋯N hydrogen bonds link mol­ecules into sheets parallel to (104). C—H⋯O inter­actions are also present