Refined partition functions for open superstrings with 4, 8 and 16 supercharges

Abstract

We analyze the perturbative massive open string spectrum of even-dimensional superstring compactifications with four, eight and sixteen supercharges. In each of such cases, we focus on universal states that exist independently on the internal geometry and other compatification details. We analytically compute refined partition functions that count these states at each mass level. Such refined partition functions are written in a super-Poincaré covariant form, providing information on how supermultiplets transform under the little group and the R symmetry. Various asymptotic limits of the partition functions and their associated quantities, such as the leading and subleading Regge trajectories, are studied empirically and analytically. In the phenomenologically relevant case of four supercharges, the partition function can be cast into the most compact form and the asymptotic formula in the large spin limit is derived explicitly. Crown Lüst et al. / Nuclear Physics B 876 (2013) Fig. 1. Classes of superstring compactifications for which we will discuss the universal particle content. The arrows within the columns represent dimensional reduction on a T 2 torus.

M‐strings, elliptic genera and N = 4 string amplitudes

“…Vertices of massive string states have first been introduced in [59] (see also [41,60] for their explicit use in string scattering amplitudes). All vertices of physical states at the first massive level have been classified and written explicitly in [61] (see also [62]). Among those we only need a very particular class.…”

Classical Limit of Higher-Spin String Amplitudes

“…When looking for a well-behaved model of fundamental higher-spin particles that satisfies high-energy unitarity constraints, string theory is a natural place to consider. Various aspects of massive states in string theory have been studied for several decades, including work on properties of the spectrum and vertex operators [69][70][71][72][73][74][75][76], and amplitude computations that probe the interaction of massive and massless string states [77][78][79][80][81][82][83][84][85][86][87][88][89][90][91]. In particular, the interaction of massive string states with gravity was the subject of several studies [92][93][94][95].…”