Celestial OPEs and $ w_{1+\infty}$ algebra from worldsheet in string theory

Understand

Celestial operator product expansions (OPEs) arise from the collinear limit of scattering amplitudes and play a vital role in celestial holography.

• In this paper, we derive the celestial OPEs of massless fields in string theory from the worldsheet.
• By studying the worldsheet OPEs of vertex operators in worldsheet CFT and further examining their behaviors in the collinear limit, we find that new vertex operators for the massless fields in string theory are generated and become dominant in the collinear limit.
• Mellin transforming to the conformal basis yields exactly the celestial OPEs in celestial CFT.