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We use aMC@NLO to study the production of four charged leptons at the LHC, performing parton showers with both HERWIG and Pythia6. Our underlying matrix element calculation features the full next-to-leading order O(α S) result and the O(α S 2) contribution of the gg channel, and it includes all off-shell, spin-correlation, virtualphoton-exchange, and interference effects. We present several key di
We use aMC@NLO to predict the ℓ? + 2-jet cross section at the NLO accuracy in QCD matched to parton shower simulations. We find that the perturbative expansion is well behaved for all the observables we study, and in particular for those relevant to the experimental analyses. We therefore conclude that NLO corrections to this process cannot be responsible for the excess of events in the dijet inva
We present results for the QCD next-to-leading order (NLO) calculation of single-top t-channel production in the 4-flavour scheme, interfaced to Parton Shower (PS) Monte Carlo programs according to the POWHEG and MC@NLO methods. Comparisons between the two methods, as well as with the corresponding process in the 5-flavour scheme are presented. For the first time results for typical kinematic dist
In this talk we give an overview of the theory status for the predictions of W boson production in association with bottom quarks with relevance to top quark phenomenology.
In this paper, we present the next-to-leading order predictions for diphoton production in the ADD model, matched to the HERWIG parton shower using the MC@NLO formalism. A selection of the results is presented for d = 2-6 extra dimensions, using generic cuts as well as analysis cuts mimicking the search strategies as pursued by the ATLAS and CMS experiments.
We present a general method that allows one to decay narrow resonances in Les Houches Monte Carlo events in an efficient and accurate way. The procedure preserves both spin correlation and finite width effects to a very good accuracy, and is therefore particularly suited for the decay of resonances in production events generated at next-to-leading-order accuracy. The method is implemented as a gen
Avsaknaden av en teknisk utbildning på mellannivå framstod i mitten av 1800-talet som såväl ett industrialiserings- som ett moderniseringshinder. Som svar på dessa problem etablerades tekniska elementarskolor under 1850-talet i Malmö, Borås, Örebro och Norrköping. Föreliggande artikel behandlar de viktigaste faktorerna bakom lokaliseringen av dessa skolor och svarar på frågorna varför de förlades
This Letter details and discusses the next-to-leading order QCD corrections to t-channel electro-weak W+bj production, where finite top-width effects are consistently taken into account. The computation is done within the aMCatNLO framework and includes both resonant and non-resonant contributions as well as interferences between the two. Results are presented for the LHC and compared to those of
We introduce a framework, based on an effective field theory approach, that allows one to perform characterisation studies of the boson recently discovered at the LHC, for all the relevant channels and in a consistent, systematic and accurate way. The production and decay of such a boson with various spin and parity assignments can be simulated by means of multi-parton, tree-level matrix elements
In this paper, we present the next-to-leading order QCD corrections for di-lepton, di-electroweak boson (ZZ, W+W-) production in both the SM and the ADD model, matched to the HERWIG parton shower using the aMC@NLO framework. A selection of results at the 8 TeV LHC, which exhibit deviations from the SM as a result of the large extra-dimension scenario, are presented.
Many highly developed Monte Carlo tools for the evaluation of cross sections based on tree matrix elements exist and are used by experimental collaborations in high energy physics. As the evaluation of one-loop matrix elements has recently been undergoing enormous progress, the combination of one-loop matrix elements with existing Monte Carlo tools is on the horizon. This would lead to phenomenolo
We present the complete next-to-leading-order (NLO) contributions to the pp→e+νeμ-ν̄μbb̄+X process in the four-flavor scheme, i.e., with massive b quarks, and its contribution to the H→WW(*) →llνν measurement in the 1-jet bin at the LHC. This background process includes top pair, single top, and non-top-quark resonant contributions. The uncertainty at NLO from the renormalization and factorization
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
