di Vecchia, Paolo5; Giuseppe, D'Appollonio6; Russo, Rodolfo3; Veneziano, Gabriele7
1 Theoretical Particle Physics and Cosmology, The Niels Bohr Institute, Faculty of Science, Københavns Universitet2 INFN3 Queen Mary College, London University4 CERN5 Theoretical Particle Physics and Cosmology, The Niels Bohr Institute, Faculty of Science, Københavns Universitet6 INFN7 CERN
Higher-derivative corrections to the Einstein-Hilbert action are present in bosonic string theory leading to the potential causality violations recently pointed out by Camanho et al. . We analyze in detail this question by considering high-energy string-brane collisions at impact parameters b ≤ l s (the string-length parameter) with l s ≫ R p (the characteristic scale of the Dp-brane geometry). If we keep only the contribution of the massless states causality is violated for a set of initial states whose polarization is suitably chosen with respect to the impact parameter vector. Such violations are instead neatly avoided when the full structure of string theory — and in particular its Regge behavior — is taken into account.
Journal of High Energy Physics (online), 2015, Vol 2015, Issue 05