Pair production of small black holes in heterotic string theories

Abstract

We study pair production of small BPS BH's in heterotic strings compactified on tori and in the FHSV model. After recalling the identification of small BH's in the perturbative BPS spectrum, we compute the tree-level amplitudes for processes initiated by massless vector bosons or gravitons. We then analyze the resulting cross sections in terms of energy and angular distributions. Finally, we briefly comment on scenari with large extra dimensions and on generalizations of our results to non-BPS, non-extremal and rotating BH's.

On stable higher spin states in heterotic string theories

“…In order to further explore the dynamical properties of BPS HS states, we will compute the 4-point scattering amplitudes involving states of this kind at tree level [25]. Due to central charge conservation we will need at least two such states in the process.…”

“…In line with previous observations [1,2,3,4], one should accept to abandon a semi-classical description and determine the nature of these peculiar string states in terms of observables such as scattering amplitudes, decay rates and form factors. In this note, relying on our previous work [25], we will take a further step in this direction. Contrary to recent analyses [5,6,7,8,9,10,11] of unstable string excitations in phenomenologically viable scenari with TeV scale tension and large extra dimension [26,27], we will mostly focus on cases with at least N = 2 whereby BPS condition guarantee the perturbative stability of higher spin states.…”

DDF operators, open string coherent states and their scattering amplitudes

“…In fact one can 'gauge away' B µ and impose P µ E µν = 0 and η µν E µν = 0 [74,75,76,31,54,53]. The explicit form of the cycle index polynomials is given by…”

“…Yet very little is known at the dynamical level [19,20]. BH production and evaporation in high energy scattering [21,22,23,24,25,26] has been addressed by several groups [27,28,29,30,31,32,33], but a complete unitary S-matrix description is still missing that is expected to include gravitational bremsstrahlung. In particular it would be extremely interesting to derive string corrections to the GW signals predicted by General Relativity [34,35,36,37,38,39,40,41].…”

“…While BRST invariant vertex operators for massless states are well known, the identification of BRST invariant vertex operators for very massive states, possibly with high spin, is rather laborious. Covariant vertex operators for massive higher spin states have been studied in the past [31,53,54,55] [ADD TAYLOR + TAIWAN] also in connection with the holographic AdS/CFT correspondence in the weak coupling / high curvature limit [56,57,58,59,60,61,62] and with scattering off D-branes in the eikonal regime [63,54,55,64,65]. Interactions of higher spins in the first Regge trajectory have been studied at tree level for the open bosonic string [66], for heterotic strings [31,53] and for (open) superstrings [67] but a systematic approach to the interactions of massive higher spin states is not yet available.…”