I will talk about a family of alpha'-corrected solutions of the Heterotic Superstring effective action describing four-dimensional black holes which are sourced by five branes, strings and Kaluza-Klein monopoles. I will then focus!

on small black holes, discussing if higher-curvature corrections can render the horizon regular or not.!

The cold dark matter (CDM) scenario has proved successful in cosmology.

However, we lack a fundamental understanding of its microscopic nature. Moreover, the

apparent disagreement between CDM predictions and subgalactic-structure observations

has prompted the debate about its behaviour at small scales. These problems could be

alleviated if the dark matter is composed of ultralight fields m ∼...

Axion and axion-like particle models are typically affected by a strong fine-tuning problem in conceiving the electroweak and the Peccei-Quinn breaking scales. Within the context of the Minimal Linear ${\sigma}$ Model, axion-like particle constructions are identified where this hierarchy problem is solved, accounting for a TeV Peccei-Quinn breaking scale and a pseudoscalar particle with a mass...

We consider Type IIA compactifications on Calabi-Yau orientifolds

with non-trivial background fluxes and mobile D6-branes. In this context, we investigate whether some known examples of stable type IIA vacua are kept in the presence of open string degrees of freedom.