9 papers
Completing Axion Double Level Crossings
Hai-Jun Li, Wei Chao, Huai-Ke Guo +1
In this work, we present the refinement of axion double level crossings within the context of multi-axion mass mixing, specifically focusing on cases where the number of axions exc…
Axion Mixing in the String Axiverse
Hai-Jun Li, Yu-Feng Zhou
String axiverse provides a fascinating and complex landscape for axion physics. The requirement in type IIB string axiverse models necessitates at least two axions to ensure the pr…
Axion effects on gamma-ray spectral irregularities. II: Implications of EBL absorption
Hai-Jun Li, Wei Chao, Xiu-Hui Tan +1
The extragalactic background light (EBL) plays a crucial role in the propagation of high-energy particles throughout the Universe. In this work, we explore the impact of the EBL ab…
Mass Mixing between QCD Axions
Hai-Jun Li, Yu-Feng Zhou
We introduce a novel level crossing phenomenon in the mass mixing between the QCD axions, one canonical QCD axion and one axion. The level crossing can take place…
Upper limit on the axion-photon coupling from Markarian 421
Hai-Jun Li, Wei Chao, Yu-Feng Zhou
Markarian 421 is a well-known nearby BL Lac blazar at the redshift . Many previous works were investigated to constrain the axion-photon coupling from its TeV gamma-ray ob…
Gravitational waves and primordial black holes from axion domain walls in level crossing
Hai-Jun Li, Yu-Feng Zhou
In this paper, we investigate the nano-Hertz gravitational waves (GWs) emission and the massive primordial black holes (PBHs) formation from the light QCD axion scenario. We consid…
Axion limits from the 10-year gamma-ray emission 1ES 1215+303
Hai-Jun Li, Wei Chao, Yu-Feng Zhou
We present the limits on photon to axionlike particle (ALP) coupling from the 10-year period observations of the TeV BL Lacertae blazar 1ES 1215+303 (with redshift ). The…
Light QCD Axion Dark Matter from Double Level Crossings
Hai-Jun Li, Ying-Quan Peng, Wei Chao +1
The even light QCD axion called the axion can both solve the strong CP problem and account for the dark matter (DM). We point out that the single and double level…
Pseudo-Dirac Sterile Neutrino Dark Matter
Wei Chao, Siyu Jiang, Zhu-Yao Wang +1
Sterile neutrino is a promising dark matter (DM) candidate. However the parameter space of this scenario has almost been ruled out by the X-ray observation results whenever the ste…