Higher Level String Resonances in Four Dimensions

TL;DR

This paper investigates higher mass Regge resonances in open superstrings, analyzing their decay rates, constructing vertex operators, and demonstrating the use of BCFW recursion relations for amplitude calculations.

Contribution

It extends previous work by analyzing the second mass level of string excitations, constructing vertex operators, and applying BCFW recursion in superstring theory.

Findings

Computed decay rates for higher spin Regge states.

Constructed vertex operators for the second mass level.

Demonstrated BCFW recursion for superstring amplitudes.

Abstract

We study higher level Regge resonances of open superstrings, focusing on the universal part of the Neveu-Schwarz sector common to all D-brane realizations of the standard model. For Regge states with masses far above the fundamental string scale, we discuss the spin-dependence of their decay rates into massless gauge bosons. Extending our previous work on lowest level string excitations, we study the second mass level at which spins range from 0 to 3. We construct the respective vertex operators and compute the amplitudes involving one massive particle and two or three gauge bosons. To illustrate the use of BCFW recursion relations in superstring theory, we build the four gluon amplitude from on-shell amplitudes involving string resonances and gauge bosons.