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A bstract We present a fully differential description of a decay of a scalar Higgs boson into massive b -quarks valid at next-to-next-to-leading order (NNLO) in perturbative quan- tum chromodynamics (QCD). We work within the nested soft-collinear subtraction scheme extended to accommodate massive partons. We include the loop-induced contribution in- volving a Higgs coupling to a top quark. We test our calculation against results existing in the literature, comparing the predictions for the total decay width and jet rates.

A bstract We present a calculation of all matching coefficients for N -jettiness beam functions at next-to-next-to-next-to-leading order (N 3 LO) in perturbative quantum chromodynamics (QCD). Our computation is performed starting from the respective collinear splitting kernels, which we integrate using the axial gauge. We use reverse unitarity to map the relevant phase-space integrals to loop integrals, which allows us to employ multi-loop techniques including integration-by-parts identities and differential equations. We find a canonical basis and use an algorithm to establish non-trivial partial fraction relations among the resulting master integrals, which allows us to reduce their number substantially. By use of regularity conditions, we express all necessary boundary constants in terms of an independent set, which we compute by direct integration of the corresponding integrals in the soft limit. In this way, we provide an entirely independent calculation of the matching coefficients which were previously computed in ref. [1].

A bstract The accurate identification of heavy-flavour jets — those which originate from bottom or charm quarks — is crucial for precision studies of the Standard Model and searches for new physics. However, assigning flavour to jets presents significant challenges, primarily due to issues with infrared and collinear (IRC) safety. This paper aims to address these challenges by evaluating recently-proposed jet algorithms designed to be IRC-safe and applicable in high-precision measurements. We compare these algorithms across benchmark heavy-flavour production processes and kinematic regimes that are relevant for LHC phenomenology. Exploiting both fixed-order calculations in QCD as well as parton shower simulations, we analyse the infrared sensitivity of these new algorithms at different stages of the event evolution and compare to flavour labelling strategies currently adopted by LHC collaborations. The results highlight that, while all algorithms lead to more robust flavour assignments compared to current techniques, they vary in performance depending on the observable and energy regime. The study lays groundwork for robust, flavour-aware jet analyses in current and future collider experiments to maximise the physics potential of experimental data by reducing discrepancies between theoretical and experimental methods.

A bstract Recent experimental and theoretical progress regarding decays led to improved bounds on the Wilson coefficients C 9 and C 10 of four-fermion operators of the |Δ B | = |Δ S | = 1 effective Hamiltonian. We analyze the resulting implications on squark flavor violation in the MSSM and obtain new constraints on flavor-changing leftright mixing in the up-squark-sector. We find the dimensionless flavor mixing parameter , depending on the flavor-diagonal MSSM masses and couplings, to be as low as ≲ 0 . 1. This has implications for models based on radiative flavor violation and leads to . Rare top decays t  →  c γ ,t  →  cg,t  →  cZ have branching ratios predicted to be below ≲ few × 10 −8 , 10 −6 and 10 −7 , respectively.

The zero-jettiness beam functions describe collinear emissions from initial state legs and appear in the factorisation theorem for cross sections in the limit of small zero-jettiness. They are an important building block for slicing schemes for colour-singlet production at hadron colliders. We report on our ongoing calculation of this quantity at next-to-next-to-next-to-leading order (N\\(^3\\)LO) in QCD, highlighting in particular the aspects of partial fraction relations and the calculation of master integrals.

We report on recently computed mixed QCD-electroweak corrections to on-shell \\(W\\) and \\(Z\\) boson production. We use these differential predictions to estimate their impact on the \\(W\\) boson mass determination at the LHC.

We present a fully differential description of a decay of a scalar Higgs boson into massive b-quarks valid at next-to-next-to-leading order (NNLO) in perturbative quantum chromodynamics (QCD). We work within the nested soft-collinear subtraction scheme extended to accommodate massive partons. We include the loop-induced contribution involving a Higgs coupling to a top quark. We test our calculation against results existing in the literature, comparing the predictions for the total decay width and jet rates.

Recently, it was observed [arXiv:2407.09363] that an aggressive cut on the \\(b\\)-jets' transverse momenta applied to Higgs-boson production in weak-boson fusion followed by the decay \\(H b b\\), leads to very large QCD corrections to the fiducial cross section. In this paper we show that these corrections are caused by soft and collinear QCD radiation and, therefore, can be efficiently treated by a parton shower. We combine the parton-shower description of the decay \\(H b b\\) with NNLO QCD corrections to Higgs production in weak-boson fusion and its subsequent decay, and demonstrate that the quality of the theoretical prediction is markedly improved even if \\(b\\)-jets with rather high transverse momenta are selected. The remaining uncertainty of the theoretical prediction, mainly driven by imprecise modelling of \\(H b b\\) decay, is estimated to be of the order of \\(O(5-7\\%)\\).

We calculate four-loop QCD corrections to the electroweak \\(\\) parameter with a non-vanishing \\(b\\) quark mass. At three loops, it was observed that elliptic integrals contribute to this observable. This prompts the question of which classes of functions appear at the next order. We report on the status of our calculation with a focus on the mathematical structures that emerge at four loops.