IISER MOHALI

Abstract: A UV complete model where the Dark Matter (DM) particle interacts with gluons via a colored scalar mediator provides a viable phenomenological model that can be tested at hadron colliders. We consider two cases. First, a zero-jet process where the complete annihilation of Standard Model (SM) particles to DM particles takes place, which contributes to the relic density of DM. The second is a Mono-jet case where an SM particle is produced along with a DM pair. Mono-jet signatures are relevant for Collider searches due to the missing transverse momentum. The Leading order contributions to these processes are loop-induced, which suffer from large-scale uncertainties. To improve the theoretical precision, we compute next-to-leading order (NLO) QCD corrections, including the evaluation of two-loop amplitudes. We discuss the ultraviolet renormalization procedure and the treatment of real emission contributions required to obtain finite predictions. Also using the results for the annihilation process, we evaluate the thermally averaged cross section, $\langle \sigma v \rangle$, at NLO and derive constraints on the parameter space of our model with the thermal relic density in a standard $\Lambda$CDM cosmology.