Observational signature and additional photon rings of an asymmetric thin-shell wormhole

Recently, a distinct shadow mechanism was proposed by Wang et al. from the asymmetric thin-shell wormhole (ATW) [X. Wang, Phys. Lett. B 811, 135930 (2020)PYLBAJ0370-269310.1016/j.physletb.2020.135930]. On the other hand, Gralla, Holz, and Wald's work [Phys. Rev. D 100, 024018 (2019)PRVDAQ2470-001010.1103/PhysRevD.100.024018] represented a nice description of photon rings in the presence of an accretion disk around a black hole. In this paper, we are inspired to thoroughly investigate the observational appearance of an accretion disk around the ATW. Although the spacetime outside an ATW with a throat could be identical to that containing a black hole with its event horizon, we show evident additional photon rings from the ATW spacetime. Moreover, a potential lensing band between two highly demagnified photon rings is found. Our analysis provides an optically observational signature to distinguish ATWs from black holes

Influence of Quantum Correction on the Black Hole Shadows, Photon Rings and Lensing Rings

We calculate the photon sphere $r_{ph}$ and critical curve $b_c$ for the quantum corrected Schwarzschild black hole, finding that they violate an universal inequalities proved for asymptotically flat black holes which satisfy null energy condition in the framework of Einstein gravity. This violation seem to be a common phenomenon when considering quantum modification of Einstein gravity. Furthermore, we study the shadows, lensing rings and photon rings in the quantum corrected Schwarzschild black hole. The violation leads to a larger bright lensing ring in the observational appearance of thin disk emission near the black hole compared with the classical Schwarzschild black hole. Our analysis may provide a observational evidence for quantum effect of general relativity.Comment: LaTex, 13 pages, 3 figures, 1 tabl

Search for heavy Majorana neutrinos at future lepton colliders

The nonzero neutrino mass can be a signal for new physics beyond the standard model. To explain the tiny neutrino mass, we can extend the standard model with right-handed Majorana neutrinos in a low-scale seesaw mechanism, while the CP violation effect can be induced due to the CP phase in the interference of heavy Majorana neutrinos. The existence of heavy Majorana neutrinos may lead to lepton number violation processes, which can be used as a probe to search for the signal of heavy Majorana neutrinos. In this paper, we focus on the CP violation effect related to two generations of heavy Majorana neutrinos for $15$ GeV $<m_N<$ $70$ GeV in the pair production of W bosons and rare decays. It is valuable to investigate the Majorana neutrino production signals and the related CP violation effects in the W boson rare decays at future lepton colliders.Comment: 12 pages, 8 figure