South-Eastern Particle Theory Alliance Sussex - RHUL - UCL 2017-2020, RHUL Node
Lead Research Organisation:
Royal Holloway University of London
Department Name: Physics
Abstract
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People |
ORCID iD |
| Nikolas Kauer (Principal Investigator) |
Publications
Arpino L
(2019)
BSM W W production with a jet veto
in Journal of High Energy Physics
Banfi A
(2019)
Composite Higgs at high transverse momentum
Banfi A
(2020)
Composite Higgs at high transverse momentum
in Journal of High Energy Physics
Kauer N
(2019)
Higgs interference effects at the one-loop level in the 1-Higgs-Singlet extension of the Standard Model
in Journal of High Energy Physics
| Description | We considered the impact on W boson pair production of the unique dimension-six operator coupling gluons to the Higgs field. In order to study this process, we had to appropriately model the effect of a veto on additional jets. This required the resummation of large logarithms of the ratio of the maximum jet transverse momentum and the invariant mass of the W boson pair. We have performed such resummation at the appropriate accuracy for the Standard Model (SM) background and for a signal beyond the SM, and devised a simple method to interface jet-veto resummations with fixed-order event generators. This resulted in the fast numerical code MCFM-RE. We compared our resummed predictions with parton-shower event generators and assessed the size of effects, such as limited detector acceptances, hadronisation and the underlying event, that were not included in our resummation. We have then used the code to compare the sensitivity of WW and ZZ production at the HL-LHC to the considered higher-dimension operator. We have found that WW can provide complementary sensitivity with respect to ZZ, provided one is able to control theory uncertainties at the percent-level. Our method is general and can be applied to the production of any colour singlet, both within and beyond the SM. Furthermore, a detailed study of Higgs interference effects at the one-loop level in the 1-Higgs-Singlet extension of the Standard Model was carried out for the W boson pair and top quark pair decay modes with fully leptonic decay. We explored interference effects for benchmark points with a large heavy Higgs mass. In the W pair channel, the Higgs signal and the interfering continuum background are loop induced. In the top pair channel, which features a tree-level background, we also calculated the interference with the one-loop background, which, due to the appearance of the absorptive part, is found to dominate the normalisation and shape of differential Higgs cross section distributions and should therefore be considered in experimental analyses. The commonly used geometric average K-factor approximation is not appropriate. We calculated with massive top and bottom quarks. Our implementation is publicly available and can be used as parton-level integrator or event generator. |
| Exploitation Route | The results could be improved by taking additional higher order effects into account, or they could motivate the study of loop-level interference effects in other phenomenologically relevant processes. |
| Sectors | Other |