Asymptotic quasinormal modes of string-theoretical d-dimensional black holes

We compute the quasinormal frequencies of $d$-dimensional spherically symmetric black holes with leading string $\alpha'$ corrections for tensorial gravitational perturbations in highly damped regime. solve perturbatively master differential equation and we monodromies perturbation variable (analytically continued to complex plane) different contours, order obtain mode spectra. proceed analogously modes test scalar fields. Differently than Einstein gravity, distinct results two cases.