Resumming transverse observables for NNLO+PS matching in GENEVA

Abstract: We study the use of higher-order resummation for transverse observables to achieve NNLO+PS matching within the GENEVA framework. In particular, we embed $q_T$ resummation for colour-singlet production at N$^3$LL obtained via soft-collinear effective theory and implemented in the library SCETlib within GENEVA. We also study for the first time the use of the generalised $N$-jettiness variable in parton shower matching, and achieve the resummation of the one-jettiness defined with transverse measures up to NLL$'$ accuracy. As a case study, we use these resummed calculations to construct a GENEVA NNLO+PS generator for Higgs boson production in heavy-quark annihilation (with beauty or charm-quarks in the initial state). The use of transverse measures facilitates the matching to showers ordered in transverse momentum, and opens the door to possible future extensions of this approach to the production of colour singlets in association with final-state jets.