String stars in d≥7

After the usual paper discussion, Gonzalo Fernández Casas will give a talk on the paper "String stars in d≥7" (2412.19888).

"We raise a thermodynamic puzzle for Horowitz--Polchinski (HP) solutions in the presence of extra compact dimensions and show that it can be resolved by the existence of higher-dimensional string stars. We provide non-trivial evidence for the existence of such string stars in spacetime dimensions d≥7 as higher-dimensional counterparts of HP solutions in bosonic and type II string theories. In particular, we explicitly construct string star solutions in d=7 that are under perturbative control. In d>7, at the Hagedorn temperature, we identify these string stars as a specific representative of a new one-parameter bounded family of Euclidean solutions which can be under perturbative control. The higher-order α′ corrections play a crucial role in our arguments and, as pointed by other works, nullify the previous arguments against the existence of string stars in d≥7. The higher-dimensional string stars have non-zero free energy at Hagedorn temperature and their mass and free energy are of the same order as those of a string-sized black hole. In d>7, these solutions are string sized, but in d=7, the size of these solutions diverges as ∼(TH−T)−1/4 near the Hagedorn temperature."