Explore the vast range of titles available.

A bstract We study the production of a W boson in association with a c-jet at the LHC. We calculate, for the first time, the complete set of NNLO QCD corrections to the dominant CKM-diagonal contribution to this process. Both signatures, pp → μ + ν μ j c and pp → μ − ν ¯ μ j c are considered. We present predictions for fiducial cross sections and differential distributions for each one of the two signatures as well as for their ratio. The theoretical predictions are compared with ATLAS measurements at 7 TeV. The results of this work are essential for the precision description of associated heavy flavor production at hadron colliders and for the determination of the strange-quark content of the proton from LHC data in NNLO QCD.

A bstract We present the first calculation of the full next-to-leading-order electroweak and QCD corrections for vector-boson scattering (VBS) into a pair of Z bosons at the LHC. We consider specifically the process pp → e + e − μ + μ − jj + X at orders O ( α 7 ) and O ( α s α 6 ) and take all off-shell and interference contributions into account. Owing to the presence of enhanced Sudakov logarithms, the electroweak corrections amount to − 16% of the leading-order electroweak fiducial cross section and induce significant shape distortions of differential distributions. The QCD corrections on the other hand are larger (+24%) than typical QCD corrections in VBS. This originates from considering the full computation including tri-boson contributions in a rather inclusive phase space. We also provide a leading-order analysis of all contributions to the cross section for pp → e + e − μ + μ − jj + X in a realistic setup.

A bstract Vector-boson scattering into two Z bosons at the LHC is a key channel for the exploration of the electroweak sector of the Standard Model. It allows for the full reconstruction of the scattering process but at the price of a huge irreducible background. For the first time, we present full next-to-leading-order predictions for pp → e + e − μ + μ − jj + X including all electroweak and QCD contributions for vector-boson scattering signal and irreducible background. The results are presented in the form of cross sections and differential distributions. A particular emphasis is put on the newly computed ( α s 2 α 5 ) corrections.

A bstract The production of top-quark pairs that subsequently decay hadronically and leptonically (lepton+jets channel) is one of the key processes for the study of top-quark properties at the LHC. In this article, NLO QCD corrections of order O α s 3 α 4 to the hadronic process pp → μ − ν ¯ μ b b ¯ j j are presented. The computation includes off-shell as well as non-resonant contributions, and experimental event selections are used in order to provide realistic predictions. The results are provided in the form of cross sections and differential distributions. The QCD corrections are sizeable and different from the ones of the fully leptonic channel. This is due to the different final state where here four jets are present at leading order.

A bstract State-of-the-art analyses of W+c-jet production at the LHC require precise predictions. In the present work, we study in detail the impact of off-diagonal CKM elements up to next-to-next-to leading order in QCD, the influence of flavored jet algorithms, and the size of electroweak corrections. In addition, we also investigate phenomenological aspects related to the exact definition of the process. We find that all these effects can be of the order of several per cent for both the fiducial cross section and differential distributions. They are, therefore, very relevant for the interpretation of current and upcoming measurements.

A bstract First, we present a combined analysis of pp → μ + v μ e − v ¯ e and pp → μ + v μ e − v ¯ e j at next-to-leading order, including both QCD and electroweak corrections. Second, we provide all-order predictions for pp → μ + v μ e − v ¯ e + jets using merged parton-shower simulations that also include approximate EW effects. A fully inclusive sample for WW production is compared to the fixed-order computations for exclusive zero- and one-jet selections. The various higher-order effects are studied in detail at the level of cross sections and differential distributions for realistic experimental set-ups. Our study confirms that merged predictions are significantly more stable than the fixed-order ones in particular regarding ratios between the two processes.

Extracting longitudinal modes of weak bosons in LHC processes is essential to understand the electroweak-symmetry-breaking mechanism. To that end, we propose a general method, based on wide neural networks, to properly model longitudinal-boson signals and hence enable the event-by-event tagging of longitudinal bosons. It combines experimentally accessible kinematic information and genuine theoretical inputs provided by amplitudes in perturbation theory. As an application we consider the production of a Z boson in association with a jet at the LHC, both at leading order and in the presence of parton-shower effects. The devised neural networks are able to extract reliably the longitudinal contribution to the unpolarised process. The proposed method is very general and can be systematically extended to other processes and problems.

A bstract We study polarisation of W-bosons produced in association with one jet at the LHC. In particular, we provide all necessary theoretical ingredients for the precise extraction of polarisation fractions. To that end, we present new polarised predictions up to NNLO QCD accuracy employing the narrow-width approximation, in two phase spaces: inclusive and fiducial. We compare results in the fiducial phase space to a full off-shell computation as well as experimental data. Finally, we fit the polarisation fractions using shape templates and show that NNLO corrections significantly improve their determination.

A bstract We present the first computation of the full next-to-leading-order QCD and electroweak corrections to the WZ scattering process at the LHC. All off-shell, gauge-boson-decay, and interference effects are taken into account for the process pp → μ + μ − e + ν e j j + X at the orders O ( α s α 6 ) and O ( α 7 ). The electroweak corrections feature the typical Sudakov behaviour towards high energy and amount to −16% relative to the electroweak contribution to the integrated cross section. Moreover, the corrections induce significant shape distortions in differential distributions. The next-to-leading-order analysis of the quark- and gluon-induced channels is supplemented by a leading-order study of all possible contributions to the full 4 ℓ + 2jets production cross section in a realistic fiducial phase-space volume.

A bstract The process pp → μ + ν μ e + ν e jj receives several contributions of different orders in the strong and electroweak coupling constants. Using appropriate event selections, this process is dominated by vector-boson scattering (VBS) and has recently been measured at the LHC. It is thus of prime importance to estimate precisely each contribution. In this article we compute for the first time the full NLO QCD and electroweak corrections to VBS and its irreducible background processes with realistic experimental cuts. We do not rely on approximations but use complete amplitudes involving two different orders at tree level and three different orders at one-loop level. Since we take into account all interferences, at NLO level the corrections to the VBS process and to the QCD-induced irreducible background process contribute at the same orders. Hence the two processes cannot be unambiguously distinguished, and all contributions to the μ + ν μ e + ν e jj final state should be preferably measured together.