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We compare the impact of top-quark spin polarization effects in Higgs boson production in association with top-quark pairs and in corresponding backgrounds at the LHC. Because of the spin-zero nature of the Higgs boson, one expects, in the chiral limit for the top quarks, a substantial complementarity in tt̄ spin correlations for a Higgs decaying into fermions/gauge-bosons and tt̄ spin correlation
We present the interface between MadGraph5-aMC@NLO, a self-contained program that calculates cross sections up to next-to-leading order accuracy in an automated manner, and APPLgrid, a code that parametrises such cross sections in the form of look-up tables which can be used for the fast computations needed in the context of PDF fits. The main characteristic of this interface, which we dub aMCfast
W bosons produced at high transverse momentum in hadron collisions can have polarization along the direction perpendicular to the production plane, which is odd under naïve T reversal where both the three-momenta and angular momenta are reversed. Perturbative QCD predicts nonzero polarization at the one-loop level, which can be measured as parity-odd components in the angular distribution of charg
Abstract: We study the production of a Higgs boson in association with bottom quarks in hadronic collisions, and present phenomenological predictions relevant to the 13 TeV LHC. Our results are accurate to the next-to-leading order in QCD, and matched to parton showers through the MC@NLO method; thus, they are fully differential and based on unweighted events, which we shower by using both Herwig+
In electroweak-boson production processes with a jet veto, higher-order corrections are enhanced by logarithms of the veto scale over the invariant mass of the boson system. In this paper, we resum these Sudakov logarithms at next-to-next-to-leading logarithmic accuracy and match our predictions to next-to-leading-order (NLO) fixed-order results. We perform the calculation in an automated way, for
Background: Due to lack of knowledge about seasonal influenza vaccine effectiveness (SIVE) against laboratory-confirmed influenza in patients aged ≥65 years a study to measure SIVE in patients admitted to hospital due to severe acute respiratory infection (SARI) in Lithuania during the 2015-2018 was conducted.Materials/methods: A test-negative case-control study was performed between 2015-2016 and
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
