arXiv subjects

Meihong Liu

Publications and source records attributed to Meihong Liu.

4 recordsLinked to original sources

arXiv2026

$b\to s\ell^+\ell^- (\ell = e, \mu, \tau)$ and $b\to s\nu\bar\nu$ at Belle and Belle II

The Belle and Belle~II experiments have accumulated a combined data set of $1.2~\mathrm{ab}^{-1}$ of $e^+e^- \to B\bar{B}$ collisions at the $\Upsilon(4S)$ resonance. Owing to the clean event environment and the well-constrained initial-state kinematics, these data are particularly well suited for studying channels involving missing energy from neutrinos. This includes the reinterpretation of $B^+\to K^+\nu\bar{\nu}$ and the first inclusive measurement of $B\to X_s\nu\bar{\nu}$ with the missing energy directly from $B$ decays, as well as searches involving missing energy from $\tau$ decays, such as $B^0\to K^{*0}\tau^+\tau^-$, $B^0\to K_S^{0}\tau^+\tau^-$, and $B^+\to K^{+}\tau^+\tau^-$.

hep-ex↗

arXiv2026

Measurements of electroweak penguin and lepton-flavour violating $B$ decays to final states with missing energy at Belle and Belle~II

The Belle and Belle~II experiments have accumulated a data set of $1.2~\mathrm{ab}^{-1}$ of $e^+e^- \to B\bar{B}$ collisions at the $\Upsilon(4S)$ resonance. Owing to the clean event environment and well-constrained initial-state kinematics, these data are ideally suited for searches for rare electroweak penguin and lepton-flavour violating $B$ decays with missing energy from neutrinos. We report results on $b\to s\nu\bar{\nu}$ processes and the interpretation, together with searches for $B\to K^{*0}\tau^+\tau^-$ and for the LFV decays $B^0\to K_S^0\tau^\pm\ell^\mp$ and $B^0\to K^{*0}\tau^\pm\ell^\mp$ ($\ell=e,\mu$).

hep-ex↗

arXiv2024

Ultrafast demagnetization in ferromagnetic materials: Origins and progress

Since the discovery of ultrafast demagnetization in Ni thin films in 1996, laser-induced ultrafast spin dynamics have become a prominent research topic in the field of magnetism and spintronics. This development offers new possibilities for the advancement of spintronics and magnetic storage technology. The subject has drawn a substantial number of researchers, leading to a series of research endeavors. Various models have been proposed to elucidate the physical processes underlying laser-induced ultrafast spin dynamics in ferromagnetic materials. However, the potential origins of these processes across different material systems and the true contributions of these different origins remain challenging in the realm of ultrafast spin dynamics. This predicament also hinders the development of spintronic terahertz emitters. In this review, we initially introduce the different experimental methods used in laser-induced ultrafast spin dynamics. We then systematically explore the magnetization precession process and present seven models of ultrafast demagnetization in ferromagnetic materials. Subsequently, we discuss the physical processes and research status of four ultrafast demagnetization origins (including spin-flipping, spin transport, non-thermal electronic distribution, and laser-induced lattice strain). Since attosecond laser technique and antiferromagnetic materials exhibit promising applications in ultrahigh-frequency spintronics, we acknowledge the emerging studies used by attosecond pules and studies on ultrafast spin dynamics in antiferromagnets, noting the significant challenges that need to be addressed in these burgeoning field.

cond-mat.mtrl-sci↗

arXiv2022

Microwave excitations and hysteretic magnetization dynamics of stripe domain films

FeNi films with the stripe domain (SD) pattern are prepared by electrodeposition and sputtering methods. The magnetic domain, static magnetic parameters, and quality factor, as well as dynamic properties of the two films, are respectively performed. The results show the magnetizations of the film were dependent on the direction of SD, and the rotation of the SD is lagging behind the magnetization reversal. The microwave properties of the SD emerge dynamic hysteresis before the saturation magnetic field. These microwave properties are selectively excited with acoustic mode, optical mode, and spin-wave mode. The frequency and intensity of different resonance modes of stripe domain are determined by the local magnetization. The magnetization variations and the rotation of SD of different modes are further illuminated by the micromagnetic simulation. The magnetic anisotropy and the resonance intensity of permeability of different modes were finally described by the modified resonance equations.

cond-mat.mtrl-sci↗