Lifetimes of light stringy states

TL;DR

This paper calculates the lifetime of light stringy states in intersecting D-brane models, showing they can have extremely long lifetimes, potentially serving as dark matter candidates.

Contribution

It provides a detailed analysis of the lifetimes of light stringy states, especially for very small intersection angles, highlighting their potential as dark matter.

Findings

Light stringy states can have lifetimes comparable to the age of the universe.

Lifetimes depend on intersection angles and can be extremely long.

Potential identification of these states as dark matter candidates.

Abstract

In this paper, we evaluate the lifetime of the light stringy states that emerge in intersecting D-brane realisations of the Standard Model. For concreteness, we focus on a light massive scalar decaying into two massless fermions. Given the present experimental lower bounds of the string scale, we extrapolate the lifetime as a function of the intersection angles to very small angles in order to have states with lifetimes of the order of the universe. That provides an alluring example of a massive, very weakly interacting field with a huge lifetime, proposing itself as a potential dark matter candidate.