Search for C=+C=+ charmonium and XYZ states in e+e−→γ+He^+e^-\to \gamma+ H at BESIII

Within the framework of nonrelativistic quantum chromodynamics, we study the production of $C=+$ charmonium states $H$ in $e^+e^-\to \gamma~+~H$ at BESIII with $H=\eta_c(nS)$ (n=1, 2, 3, and 4), $\chi_{cJ}(nP)$ (n=1, 2, and 3), and $^1D_2(nD)$ (n=1 and 2). The radiative and relativistic corrections are calculated to next-to-leading order for $S$ and $P$ wave states. We then argue that the search for $C=+$ $XYZ$ states such as $X(3872)$, $X(3940)$, $X(4160)$, and $X(4350)$ in $e^+e^-\to \gamma~+~H$ at BESIII may help clarify the nature of these states. BESIII can search $XYZ$ states through two body process $e^+e^-\to \gamma H$, where $H$ decay to $J/\psi \pi^+\pi^-$, $J/\psi \phi$, or $D \bar D$. This result may be useful in identifying the nature of $C=+$ $XYZ$ states. For completeness, the production of $C=+$ charmonium in $e^+e^-\to \gamma +~H$ at B factories is also discussed.Comment: Comments and suggestions are welcome. References are update

Is the late near-infrared bump in short-hard GRB 130603B due to the Li-Paczynski kilonova?

Short-hard gamma-ray bursts (GRBs) are widely believed to be produced by the merger of two binary compact objects, specifically by two neutron stars or by a neutron star orbiting a black hole. According to the Li-Paczynski kilonova model, the merger would launch sub-relativistic ejecta and a near-infrared/optical transient would then occur, lasting up to days, which is powered by the radioactive decay of heavy elements synthesized in the ejecta. The detection of a late bump using the {\em Hubble Space Telescope} ({\em HST}) in the near-infrared afterglow light curve of the short-hard GRB 130603B is indeed consistent with such a model. However, as shown in this Letter, the limited {\em HST} near-infrared lightcurve behavior can also be interpreted as the synchrotron radiation of the external shock driven by a wide mildly relativistic outflow. In such a scenario, the radio emission is expected to peak with a flux of $\sim 100 \mu$Jy, which is detectable for current radio arrays. Hence, the radio afterglow data can provide complementary evidence on the nature of the bump in GRB 130603B. It is worth noting that good spectroscopy during the bump phase in short-hard bursts can test validity of either model above, analogous to spectroscopy of broad-lined Type Ic supernova in long-soft GRBs.Comment: 4 pages, 2 figures, published in ApJ Lette

A supra-massive magnetar central engine for short GRB 130603B

We show that the peculiar early optical and in particular X-ray afterglow emission of the short duration burst GRB 130603B can be explained by continuous energy injection into the blastwave from a supra-massive magnetar central engine. The observed energetics and temporal/spectral properties of the late infrared bump (i.e., the "kilonova") are also found consistent with emission from the ejecta launched during an NS-NS merger and powered by a magnetar central engine. The isotropic-equivalent kinetic energies of both the GRB blastwave and the kilonova are about $E_{\rm k}\sim 10^{51}$ erg, consistent with being powered by a near-isotropic magnetar wind. However, this relatively small value demands that most of the initial rotational energy of the magnetar $(\sim {\rm a~ few \times 10^{52}~ erg})$ is carried away by gravitational wave radiation. Our results suggest that (i) the progenitor of GRB 130603B would be a NS-NS binary system, whose merger product would be a supra-massive neutron star that lasted for about $\sim 1000$ seconds; (ii) the equation-of-state of nuclear matter would be stiff enough to allow survival of a long-lived supra-massive neutron star, so that it is promising to detect bright electromagnetic counterparts of gravitational wave triggers without short GRB associations in the upcoming Advanced LIGO/Virgo era.Comment: Five pages including 1 Figure, to appear in ApJ

Impact of Lycium barbarum polysaccharide on apoptosis in Mycoplasma-infected splenic lymphocytes

Purpose: To evaluate the effect of Lycium barbarum polysaccharide (LBP) on apoptosis in Mycoplasma-infected splenic lymphocytes (SLs), and the underlying mechanisms.Methods: SLs isolated from C57BL/6J mice were infected with Mycoplasma. The infected SLs were administered at different concentrations of LBP for 4 h, and the proportions of apoptotic cells and levels of relative reactive oxygen species (ROS) were determined by flow cytometry. The expressions of proapoptotic genes and endogenous antioxidant enzymes were investigated by real-time polymerase chain reaction (RT-PCR) and Western blotting.Results: LBP treatment produced dose-dependent reductions in apoptotic ratio and intracellular ROS levels of SLs (p < 0.05). In addition, the expressions of pro-apoptotic genes were decreased by LBP treatment with respect to mRNA and protein levels (p < 0.05). In contrast, mRNA and protein levels of anti-apoptotic factor Bcl-2 were significantly increased in a dose-dependent manner (p < 0.05). Furthermore, RT-PCR and Western blot results demonstrated that the expression levels of mRNA and proteins in Nrf2, HO-1 and NQO1 were up-regulated by Mycoplasma infection (p < 0.01), and further increased by LBP treatment (p < 0.05).Conclusion: LBP exerts a hyperactive antioxidant response encoded by Nrf2 to protect SLs from apoptosis induced by ROS-related oxidative damage after Mycoplasma infection. These results suggest that LBP may serve as a beneficial and dietary anti-Mycoplasma and anti-apoptotic agent.Keywords: Lycium barbarum polysaccharide, Splenic lymphocytes, ROS, Caspase-3, Bax, Nrf