Probing the dilaton in central exclusive processes at the LHC

Abstract

The existence of a dilaton as a pseudo-Nambu-Goldstone boson in spontaneous breaking of scale symmetry is predicted in beyond standard model theories in which electroweak symmetry is broken via strongly coupled conformal dynamics. Such a particle is expected to have a mass below the conformal symmetry breaking scale $f$ and couplings to standard model particles similar to those of the SM Higgs boson. In this paper we estimate, for the first time, the dilaton production in exclusive processes considering Pomeron - Pomeron ($\pom \pom$) and photon - photon ($\gamma \gamma$) interactions, which are characterized by two rapidity gaps and intact hadrons in the final state. Our results indicate that if the dilaton is massive ($M_{\chi} \ge 2 M_W$), the study of dilaton production by $\pom \pom$ interactions in $pp$ collisions can be useful to determine its mass and the conformal energy scale.