Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - HEFTinLOOPS (Effective Field Theory predictions for Higgs production processes at the Large Hadron Collider)

Teaser

The Large Hadron Collider (LHC) is hunting for signs of New Physics in the vast amount of data collected by its experiments. If new states are heavier than the collider energy reach, their presence can be revealed by modications of the interactions of the known particles. The...

Summary

The Large Hadron Collider (LHC) is hunting for signs of New Physics in the vast amount of data collected by its experiments. If new states are heavier than the collider energy reach, their presence can be revealed by modications of the interactions of the known particles. The Standard Model Effective Field Theory (SMEFT) parametrises such deviations from the Standard Model, extending the sensitivity to scales beyond those directly probed at colliders. Determining the parameters of the EFT will shed light on the nature of New Physics and will provide hints to the most important questions in particle physics. A dedicated campaign of measurements and their SMEFT interpretation is a major goal of the LHC and requires coordination between experimentalists and theorists. In this effort precise predictions for Higgs and top production in the SMEFT are necessary, and my project aimed to address this challenge.

My project provided important theoretical predictions for the SMEFT programme at the LHC and also the corresponding Monte Carlo tools which can be used by experimentalists and theorists. The project resulted in a series of publications in peer review journals on higher-order, precise computations of various scattering processes at the LHC, focusing on the top and Higgs sectors, as well as on the interpretation of LHC measurements within the SMEFT.

Work performed

The project has resulted in the computation of higher-order, NLO QCD and electroweak corrections for the Effective Field Theory framework. The project focused on the top and Higgs sectors, providing predictions for Higgs and top production. In addition to providing theoretical predictions, the project analysed LHC data in the Effective Field Theory framework, providing constraints on the dimension-6 operators.

The project resulted in 7 publications in peer review journals, with one additional manuscript submitted for publication in the last month. Results have been presented at international conferences and workshops, as well as at invited seminars. About 30 talks were given during the fellowship. The project resulted also in public codes which have been used by both theorists and experimentalists working in particle physics.

Final results

The project resulted in beyond the state-of-the-art theoretical predictions in the framework of the Standard Model Effective Field Theory and produced the first public tools necessary for precise computations. The project resulted also in the first global interpretation of measurements from the LHC involving the top quark, for the first time using higher-order, precise predictions and taking into account all the theoretical and experimental uncertainties. This part of the project provided the most precise and stringent constraints on the higher-dimension operators involving the top quark. The theoretical results of the project and the associated tools have been extensively used by the wider particle physics community, both theorists and experimentalists.