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The associated production of a Higgs boson and a top-quark pair, tt¯H, in proton-proton collisions is addressed in this paper for a center of mass energy of 13 TeV at the LHC. Dileptonic final states of tt¯H events with two oppositely charged leptons and four jets from the decays t→bW+→b+ν, t¯→b¯W-→b¯-ν¯ and h→bb¯, are used. Signal events, generated with MadGraph5-aMC@NLO, are fully reconstructed
We present an interface between the multipurpose Monte Carlo tool MadGraph5_aMC@NLO and the automated amplitude generator GoSam. As a first application of this novel framework, we compute the NLO corrections to (Formula presented.) (Formula presented.) and (Formula presented.) (Formula presented.) matched to a parton shower. In the phenomenological analyses of these processes, we focus our attenti
Abstract: We consider improving Powheg+Minlo simulations, so as to also render them NLO accurate in the description of observables receiving contributions from events with lower parton multiplicity than present in their underlying NLO calculation. On a conceptual level we follow the strategy of the so-called Minlo′programs. Whereas the existing Minlo′framework requires explicit analytic input from
We study the production of a Standard Model Higgs boson in the gluon-fusion channel at the 13 TeV LHC. Our results are accurate to the next-to-leading order in QCD, bar for the lack of some two-loop amplitudes, for up to two extra jets and are matched to the Pythia8 Monte Carlo. We address the impact, at the level of inclusive rates and of differential distributions, of the merging of samples char
Global dementia rates will more than triple by 2050, thus challengingsociety. Due to ageing in place policies, informal caregiving is increasing asmore people with dementia continue living at home despite significant careneeds. While most caregivers are willing to act as such, they are notalways adequately supported, thus reporting a high burden, worse mentaland physical health. Innovative Assisti
We consider the impact of the tt spin correlations in the Higgs boson production in association with top quark pairs pp→ttH and in the corresponding backgrounds. We study the H→bb and H→γγ decay modes. We show that retaining the tt spin-correlation effects could significantly improve the LHC sensitivity to the ttH signal, particularly in the H→γγ channel.
In this talk an interface is presented between the multi-purpose next-to-leading-order Monte Carlo tool MADGRAPH5-AMC@NLO and the automated one-loop amplitude generator GOSAM. As a phenomenological application of this work, the interface is used to make predictions for the ttH and ttgg processes at the 13 TeV LHC. The differences between these two processes is studied, focussing in particular on o
During the last years, the improvement in predictions for LHC processes has been enormous. In this talk the following two topics are covered. First, using the FxFx merging prescription, the prediction and data comparison for a vector boson in association with multiple jets are considered at NLO accuracy. Second, we show some results for the newly developed extension of the MINLO method that allows
The determination of the CP nature of the Higgs coupling to top quarks is addressed in this paper, using tt-h events produced in s=13 TeV proton-proton collisions at the LHC. Dileptonic final states are employed, with two oppositely charged leptons and four jets, corresponding to the decays t→bW+→b+ν, t-→b-W-→b--ν-, and h→bb-. Pure scalar (h=H), pure pseudoscalar (h=A), and CP-violating Higgs boso
In this paper, the recent progress in improving the Minlo procedure for generating inclusive event samples that are (N)NLO accurate in various jet multiplicities is discussed. As a proof of principle, a selection of the predictions for Higgs boson production in association with up to two jets is shown. The predictions are simultaneously accurate at NNLO for observables inclusive in H production, N
We calculate the complete-NLO predictions for tt¯ W± and tt¯ tt¯ production in proton-proton collisions at 13 and 100 TeV. All the non-vanishing contributions of O(αsiαj) with i + j = 3, 4 for tt¯ W± and i + j = 4, 5 for tt¯ tt¯ are evaluated without any approximation. For tt¯ W± we find that, due to the presence of tW → tW scattering, at 13(100) TeV the O(αsα3) contribution is about 12(70)% of th
Vector-boson scattering processes are of great importance for the current run-II and future runs of the Large Hadron Collider. The presence of triple and quartic gauge couplings in the process gives access to the gauge sector of the Standard Model (SM) and possible new-physics contributions there. To test any new-physics hypothesis, sound knowledge of the SM contributions is necessary, with a prec
We present the key features relevant to the automated computation of all the leading- and next-to-leading order contributions to short-distance cross sections in a mixed-coupling expansion, with special emphasis on the first subleading NLO term in the QCD+EW scenario, commonly referred to as NLO EW corrections. We discuss, in particular, the FKS subtraction in the context of a mixed-coupling expan
We present a next-to-leading order accurate simulation of t-channel single-top plus jet production matched to parton showers via the Powheg method. The calculation underlying the simulation is enhanced with a process-specific implementation of the multi-scale improved NLO (Minlo) method, such that it gives physical predictions all through phase space, including regions where the jet additional to
In this talk some of the recent developments within the MadGraph/MadEvent framework are presented.
Background: The aim of this study was to describe patients' experiences and perceived causes of persisting discomfort following day surgery. Earlier research has mainly covered symptoms and signs during a recovery period of up to one month, and not dealt with patients' perceptions of what causes persisting, longer-term discomfort.Methods: This study is a part from a study carried out during the pe
In this paper we give an overview of the theory status for the predictions of single-top cross sections via the s and t channels.
In this talk three 2-sigma deviations from the Standard Model predictions in the top quark sector are briefly discussed. These are the excess of events in the tail of the H T distribution in tt events, the top-quark charge asymmetry and the discrimination of s- and t-channel events in single top. The latter has only been observed by CDF, while the other two are found by both CDF and DØ.
