From S-matrix theory to strings: Scattering data and the commitment to non-arbitrariness

Area of Science:

• Theoretical physics
• High-energy physics
• Quantum gravity

Background:

• String theory originated in the late 1960s/early 1970s within the S-matrix program for strong interactions.
• Initially, string models were explored for strong interaction physics before being reinterpreted for unifying fundamental forces.

Purpose of the Study:

• To historically analyze the development of string theory from S-matrix physics.
• To clarify the shift from an experiment-dependent S-matrix program to modern, data-detached string theory.
• To investigate the reasons behind string theory's detachment from experimental data.

Main Methods:

• Historical analysis of theoretical physics development.
• Examination of the S-matrix program and dual resonance models.
• Tracing the evolution of theoretical practices and motivations in string theory.

Main Results:

• String theory's roots lie in the S-matrix program, initially focused on strong interactions.
• A significant shift occurred in the mid-1970s, reinterpreting string models for quantum gravity and unification.
• Physicists moved away from experimental dependence due to a commitment to theoretical "non-arbitrariness" (lack of free parameters) in dual resonance models.

Conclusions:

• The detachment of string theory from experimental data predates its reinterpretation as a quantum gravity theory.
• The pursuit of theoretical elegance and parameter determination through reasoning, not experimental accessibility, drove this shift.
• This historical trajectory offers crucial insights into the role of experimental data in the evolution of string theory.