Resonance mass spectra of gravity and fermion on Bloch branes

Abstract

In this paper, by presenting the potentials of Kaluza-Klein (KK) modes in the corresponding Schr\"{o}dinger equations, we investigate the localization and resonances of gravity and fermion on the symmetric and asymmetric Bloch {branes}. We find that the localization properties of zero modes for gravity and fermion in the symmetric brane case are the same, whereas, for the asymmetric brane case, the fermion zero mode is localized on one of the sub-branes, while the gravity zero mode is localized on another sub-brane. The spectra of the gravity and the left- or right-handed fermion are composed of a bound zero mode and a series of gapless continuous massive KK modes. Among the continuous massive KK modes, we obtain some discrete gravity and fermion resonant (quasilocalized) KK states on the brane, which have a finite probability of escaping into the bulk. The KK states with lower resonant masses have a longer lifetime on the brane. And the number of the resonant KK states increases linearly with the width of the brane and the scalar-fermion coupling constant, {but it decreases with the asymmetric factor $\beta$}. The structure of the resonance spectrum is investigated in detail.