How did Leonard Susskind, Holger Nielsen, and Yoichiro Nambu connect string vibrations to particle physics?

In the late 1960s, Gabriele Veneziano discovered that a mathematical formula known as the Euler beta function could describe data related to the strong force, which binds protons and neutrons within atomic nuclei.1

Building on this insight, Leonard Susskind, Holger Nielsen, and Yoichiro Nambu demonstrated that the underlying mathematics described the vibrational motion of minuscule filaments of energy resembling tiny strands of string. This work suggested that the strong force functioned like strings tethering particles to their endpoints.1

This concept evolved into modern string theory, which posits that all particles are actually tiny strings. Just as a violin string produces different musical notes based on its vibration, these strings produce different particles—such as electrons or quarks—depending on their specific vibrational patterns. Consequently, the mass and charge of a particle are determined by how its constituent string vibrates.2