Comments on the high energy limit of bosonic open string theory

Abstract

In previous works, ratios among four-point scattering amplitudes at the leading order in the high-energy limit were derived for the bosonic open string theory. The derivation was based on Ward identities derived from the decoupling of zero-norm states and was purely algebraic. The only assumption of the derivation was that the momentum polarization can be approximated by the longitudinal polarization at high energies. In this paper, using the decoupling of spurious states, we reduce this assumption to a much weaker one which can be easily verified by simple power counting in most cases. For the special cases which are less obvious, we verify the new assumption for an example by saddle-point approximation. We also provide a new perspective to our previous results in terms of DDF states. In particular, we show that, by using DDF states, one can easily see that there is only one independent high energy scattering amplitude for each fixed mass level.Comment: 14 pages, no figur

Higher Spin String States Scattered from D-Particle in the Regge Regime and Factorized Ratios of Fixed Angle Scatterings

“…However, we discover that in spite of the non-factorizability of the closed string D-particle scattering amplitudes, the complete ratios derived for the fixed angle regime are found to be factorized. These ratios are consistent with the decoupling of high-energy zero norm states calculated previously [4][5][6][7][8][9][10][11]. This paper is organized as follows.…”

“…For open string-string scatterings, either the saddle-point method (t − u channel only) or the decoupling of high-energy zero-norm states (ZNS) can be used to calculate the fixed angle ratios [4][5][6][7][8][9]. It was discovered that there was an interesting link between high-energy fixed angle amplitudes T and RR amplitudes A.…”

Linear relations and their breakdown in high energy massive string scatterings in compact spaces

“…This is physically consistent as one expects a m R , 1 2 nR dependent Regge-pole and zero structures in the high energy string scattering amplitudes. In conclusion, in the GR, Presumably, the infinite linear relations obtained above can be reproduced by using the method of high energy ZNS, or high energy Ward identities, adopted in the previous works [4,5,6,7,8,9,10,11]. The existence of Soliton ZNS at arbitrary mass levels was constructed in [22].…”

Notes on high-energy limit of bosonic closed string scattering amplitudes

“…Recently high-energy, fixed-angle behavior of string scattering amplitudes [1,2,3] was intensively reinvestigated [4,5,6,7,8,9,10]. The motivation was to uncover the long-sought hidden stringy space-time symmetry.…”