Detectors in weaklycoupled field theories
Abstract
We initiate a study of asymptotic detector operators in weaklycoupled field theories. These operators describe measurements that can be performed at future null infinity in a collider experiment. In a conformal theory they can be identified with lightray operators, and thus have a direct relation to the spectrum of the theory. After a general discussion of the underlying physical picture, we show how infrared divergences of general detector operators can be renormalized in perturbation theory, and how they give rise to detector anomalous dimensions. We discuss in detail how this renormalization can be performed at the intersections of the Regge trajectories where nontrivial mixing occurs, which is related to the poles in anomalous dimensions at special values of spin. Finally, we discuss novel horizontal trajectories in scalar theories and show how they contribute to correlation functions. Our calculations are done in the example of ϕ^{4} theory in d = 4 − ϵ dimensions, but the methods are applicable more broadly. At the WilsonFisher fixed point our results include an explicit expression for the Pomeron lightray operator at two loops, as well as a prediction for the value of the Regge intercept at five loops.
 Publication:

Journal of High Energy Physics
 Pub Date:
 April 2023
 DOI:
 10.1007/JHEP04(2023)014
 arXiv:
 arXiv:2209.00008
 Bibcode:
 2023JHEP...04..014C
 Keywords:

 Field Theories in Higher Dimensions;
 Renormalization and Regularization;
 Conformal and W Symmetry;
 Scale and Conformal Symmetries;
 High Energy Physics  Theory
 EPrint:
 58 pages + appendices, 21 figure