We present the QCD radiative corrections to the full off-shell $\rm t\bar{t}W^+$ production, considering a final state with three charged leptons, two b jets and missing energy. All interferences, off-shell effects and spin correlations are included in the calculation. Beyond presenting integrated and differential results for the full off-shell process, we compare them with those obtained applying a double-pole approximation to the virtual corrections.
We present details of a calculation of the cross section for hadronic top-antitop production in next-to-leading order (NLO) QCD, including the decays of the top and antitop into bottom quarks and leptons. This calculation is based on matrix elements for νe e+ μ- \barν_μb\bar{b} production and includes all non-resonant diagrams, interferences, and off-shell effects of the top quarks. Such contributions are formally suppressed by the top-quark width and turn out to be small in the inclusive cross section. However, they can be strongly enhanced in exclusive observables that play an important role…
We present the calculation of scalar and pseudoscalar Higgs production in association with a top-antitop pair to the next-to-leading order (NLO) accuracy in QCD, interfaced with parton showers according to the MC@NLO formalism. We apply our results to the cases of light and very light Higgs boson production at the LHC, giving results for total rates as well as for sample differential distributions, relevant to the Higgs, to the top quarks, and to their decay products. This work constitutes the first phenomenological application of aMC@NLO, a fully automated approach to complete event generatio…
We compute the hadronic production of top-antitop pairs in association with a Higgs boson at next-to-leading-order QCD, including the decay of the top and antitop quark into bottom quarks and leptons. Our computation is based on full leading and next-to-leading-order matrix elements for $e^+ ν_e μ^-\barν_μb \bar{b} H(j)$ and includes all non-resonant contributions, off-shell effects and interferences. Numerical results for the integrated cross section and several differential distributions are given for the LHC operating at 13 TeV using a fixed and a dynamical factorization and renormalization…
A brief summary of the calculation of the NLO QCD corrections to the process pp -> e+ ve mu- v_mu bb~ j + X is reported. This provides a complete description of the process of t-tbar + jet production with leptonic decays beyond the narrow-width approximation. Off-shell effects for top quarks and W boson decays are fully taken into account, namely all resonant and non-resonant contributions are included in the fixed-order calculation. Selected results for total and differential cross sections are shown for the case of the LHC Run I at the energy of 8 TeV.
The PowHel framework allows to make predictions of total and differential cross-sections of multiparticle hadroproduction processes at both NLO QCD accuracy and NLO QCD matched to Parton Shower, on the basis of the interface between the POWHEG-BOX and HELAC-NLO codes. It has already been applied to study several processes involving a top-antitop pair in association with a third particle or hadronic jet. Our most recent predictions concern top-antitop-V hadroproduction (with V = W or Z), at both parton and hadron level, by considering different decay channels (hadronic and leptonic) of the heav…
We emphasize the role that the associated production of a Higgs boson with a pair of top-antitop quarks can play at present and future hadron colliders. Results of recent calculations of the NLO total cross section for the associated production of a Standard Model like Higgs boson with a pair of top-antitop quarks at the Tevatron (sqrt(s)=2 TeV) are presented.
Resonance-aware parton-shower matching for off-shell top-antitop production with semi-leptonic decays at electron-positron colliders
Institut für Theoretische Physik und Astrophysik, Universität Würzburg（维尔茨堡大学理论物理与天体物理研究所）；Dipartimento di Fisica, Università di Torino, and INFN, Sezione di Torino（都灵大学物理系及意大利国家核物理研究院都灵分部）；Physikalisches Institut, Albert-Ludwigs-Universität Freiburg（弗赖堡大学阿尔伯特·路德维希物理研究所）；Dipartimento di Fisica, Università di Milano–Bicocca and INFN, Sezione di Milano–Bicocca（米兰比可卡大学物理系及意大利国家核物理研究院米兰比可卡分部）
We study the production of a Higgs boson in association to a top-antitop pair at the Large Hadron Collider. We show how precise predictions for the differential distributions with respect to the transverse momentum of the Higgs boson, to the invariant mass of the top-antitop-Higgs system and to the invariant mass of the top-antitop pair can provide useful information on the possible presence of a pseudoscalar component in the coupling of the top quark with the Higgs boson. We evaluate the production of a top-antitop pair and a Higgs boson to next-to-leading order in fixed order perturbation th…
For the first time the next-to-leading-order electroweak corrections to the full off-shell production of two top quarks that decay leptonically are presented. This calculation includes all off-shell, non-resonant, and interference effects for the 6-particle phase space. While the electroweak corrections are below one per cent for the integrated cross section, they reach up to 15% in the high-transverse-momentum region of distributions. To support the results of the complete one-loop calculation, we have in addition evaluated the electroweak corrections in two different pole approximations, one…
Top-antitop quark pairs belong to the most abundantly produced and precisely measurable heavy-particle signatures at hadron colliders and allow for crucial tests of the Standard Model and new-physics searches. Here we report on the calculation of the next-to-leading order (NLO) QCD corrections to hadronic WWbb production, which provides a complete NLO description of the production of top-antitop pairs and their subsequent decay into W bosons and bottom quarks, including interferences, off-shell effects, and non-resonant backgrounds. Numerical predictions for the Tevatron and the LHC are presen…
We present NLO electroweak corrections to Higgs production in association with off-shell top-antitop quark pairs. The full process $\text{p}\text{p}\to\text{e}^+ν_{\text{e}} μ^-\barν_μ\text{b}\bar{\text{b}} \text{H}$ is considered, and hence all interference, off-shell, and non-resonant contributions are taken into account. The electroweak corrections turn out to be below one per cent for the integrated cross section but can exceed $10\%$ in certain phase-space regions. In addition to its phenomenological relevance, the computation constitutes a major technical achievement as the full NLO virt…
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 $\mathcal{O}{\left(α_{\rm s}^3α^{4}\right)}$ to the hadronic process ${\rm p}{\rm p}\to μ^-\barν_μ{\rm b}\bar{\rm b} {\rm j} {\rm j}$ 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 an…
We present the results of the computation of the next-to-leading order QCD corrections to the production cross section of a Higgs boson in association with a top-antitop pair at the LHC, including the three relevant dimension-six operators ($O_{t φ}, O_{φG}, O_{tG}$) of the standard model effective field theory. These operators also contribute to the production of Higgs bosons in loop-induced processes at the LHC, such as inclusive Higgs, $Hj$ and $HH$ production, and modify the Higgs decay branching ratios for which we also provide predictions. We perform a detailed study of the cross section…
The recent developments on the computation of non-resonant corrections to the e+ e- -> W+ W- b bbar cross section in the top-antitop resonance region are reviewed in this talk. Non-resonant production of the final state W+ W- b bbar starts to contribute at NLO in the nonrelativistic power-counting v ~ alpha_s ~ sqrt(alpha_EW). The corrections induced by non-resonant effects reduce the cross section in the top-antitop resonance peak region at a level which is comparable to the expected experimental precision at the future linear collider, and are thus relevant for a high-precision top mass and …
We present the complete next-to-leading order (NLO) QCD and NLO electroweak (EW) corrections to the $W$-boson pair production associated with a hard jet at the LHC including the spin correlated $W$-boson leptonic decays. The dependence of the leading order (LO) and NLO corrected cross sections on the jet transverse momentum cut is investigated. In dealing with the subsequent resonant $W$-boson decays, we adopt the {\sc MadSpin} method where the spin correlation effect is included. We also provide the LO and NLO corrected distributions of the transverse momenta and rapidities of final products.…
We compute the next-to-leading order QCD corrections to WZ+jet production at the Tevatron and the LHC, including decays of the electroweak bosons to light leptons with all off-shell effects taken into account. The corrections are sizable and have significant impact on the differential distributions.
The computation of the NLO QCD corrections to the cross sections for W+W- gamma and ZZgamma production in hadronic collisions is presented. We consider the case of a real photon in the final state, but include full leptonic decays of the W and Z bosons. Numerical results for the LHC and the Tevatron are obtained through a fully flexible parton level Monte Carlo based on the structure of the VBFNLO program, allowing an easy implementation of arbitrary cuts and distributions. We show the dependence on scale variations of the integrated cross sections and provide evidence that NLO QCD corrections…
In this paper we present the full NLO QCD + NLO EW corrections to the $Z$-boson pair production in association with a hard jet at the LHC. The subsequent $Z$-boson leptonic decays are included by adopting both the naive NWA and MadSpin methods for comparison. Since the $ZZ+{\rm jet}$ production is an important background for single Higgs boson production and new physics search at hadron colliders, the theoretical predictions with high accuracy for the hadronic production of $ZZ+{\rm jet}$ are necessary. We present the numerical results of the integrated cross section and various kinematic dist…
In this talk we present results of our recent calculations of cross sections and distributions for the associate production of top-antitop quark pairs with a heavy boson (Higgs, W, Z) at the LHC, obtained using threshold resummation in direct QCD, i.e. in the Mellin-space approach.
We present a computation of the O(alpha_s) QCD corrections to W^\pm Z γproduction at the Large Hadron Collider. The photon is considered as real, and we include full leptonic decays for the W and Z bosons. Based on the structure of the VBFNLO program package, we obtain numerical results through a fully flexible Monte Carlo program, which allows to implement general cuts and distributions of the final-state particles. The NLO QCD corrections are sizable and strongly exceed the theory error obtained by a scale variation of the leading-order result. Also, the shapes of relevant observables are si…
In this paper we present the NLO QCD + NLO EW corrections to the $ZZZ$ production with subsequent $Z$-boson leptonic decays at the LHC by adopting the improved narrow width approximation, which takes into account off-shell contributions and spin correlations. Integrated cross sections at $13$, $14$, $33$ and $100~{\rm TeV}$ hadron colliders and various kinematic distributions are presented. Our numerical results show that the jet emission correction accounts for a large part of the total QCD correction, especially in the high energy region. By applying a proper cut to the jet transverse moment…
We present the NLO QCD corrections to the processes p p and p anti-p to W+ W- b anti-b including leptonic decays of the W bosons. Non-resonant contributions as well as diagrams with doubly resonant and singly resonant top quark propagators are fully taken into account. We employ the narrow width approximation to perform the decays of the W bosons; spin correlations are however preserved. We also calculate observables relevant for top quark mass measurements, and study the impact of kinematical requirements and different scale choices on t anti-t asymmetries.
The calculation of $t\bar{t}Z$ production including leptonic decays of both $Z$ boson and top quarks via a partially or fully off-shell calculation represents a definite step forward towards a more accurate description of events whose signatures originate from $t\bar{t}Z$ production. In this talk we review two studies that represent the state of the art of theoretical modeling of $t\bar{t}Z$ production by either performing the NLO QCD calculation of the fully decayed $pp\rightarrow e^+ν_eμ^-\barν_μb\bar{b}τ^+τ^-$ process (see Ref. [1]) or matching the NLO QCD calculation of $pp\rightarrow t\ba…
Top-Antitop Production and Decay at Threshold at the LHC in QCD Perturbation Theory
INFN, Sezione di Milano-Bicocca（意大利国家核物理研究所米兰比可卡分部）；Dipartimento di Fisica G. Occhialini, Università degli Studi di Milano-Bicocca（米兰比可卡大学G. Occhialini物理系）
We compute the 1-loop (alpha_s^2) correction to hard spectator scattering in non-leptonic B decay tree amplitudes. This forms part of the NNLO contribution to the QCD factorization formula for hadronic B decays, and introduces a new rescattering phase that corrects the leading-order result for direct CP asymmetries. Among the technical issues, we discuss the cancellation of infrared divergences, and the treatment of evanescent four-quark operators. The infrared finiteness of our result establishes factorization of spectator scattering at the 1-loop order. Depending on the values of hadronic in…
We report on the calculation of the next-to-leading order QCD corrections to the production of W-boson pairs in association with a hard jet at the Tevatron and the LHC, which is an important source of background for Higgs and new-physics searches. Leptonic decays of the W bosons are included by applying an improved version of the narrow-width approximation that treats the W bosons as on-shell particles, but keeps the information on the W spin. A selection of differential NLO QCD cross sections is provided both for the LHC and the Tevatron. The QCD corrections stabilize the LO prediction for th…
We report on the precision predictions for the $e^+e^-\to ZZγ$ process including $Z$-boson leptonic decays at the ILC in the standard model (SM). The calculation includes the full next-to-leading (NLO) electroweak (EW) corrections and high order initial state radiation (h.o.ISR) contributions. We find that the NLO EW corrections heavily suppress the LO cross section, and the h.o.ISR effects are notable near the threshold while become small in high energy region. We present the LO and the NLO EW+h.o.ISR corrected distributions of the transverse momenta of final $Z$-boson and photon as well as t…
We present a calculation of the next-to-leading-order electroweak corrections to W+γ production, including the leptonic decay of the W boson and taking into account all off-shell effects of the W boson, where the finite width of the W boson is implemented using the complex-mass scheme. Corrections induced by incoming photons are fully included and find particular emphasis in the discussion of phenomenological predictions for the LHC. The corresponding next-to-leading-order QCD corrections are reproduced as well. In order to separate hard photons from jets, a quark-to-photon fragmentation funct…
The production of a Higgs boson in association with a pair of top-antitop or bottom-antibottom quarks plays a very important role at both the Tevatron and the Large Hadron Collider. The theoretical prediction of the corresponding cross sections has been improved by including the complete next-to-leading order QCD corrections. After a brief description of the most relevant technical aspects of the calculation, we review the results obtained for both the Tevatron and the Large Hadron Collider
We report on the calculation of the next-to-leading order QCD corrections to the production of W-boson pairs in association with a hard jet at the Tevatron and the LHC, which is an important source of background for Higgs and new-physics searches. Leptonic decays of the W bosons are included by applying an improved version of the narrow-width approximation that treats the W bosons as on-shell particles, but keeps the information on the W spin. Contributions from external bottom quarks are neglected, because they are either numerically suppressed or should be attributed to different processes s…
We complete the computation of the 1-loop (alpha_s^2) corrections to hard spectator scattering in non-leptonic B decays at leading power in Lambda/m_b by evaluating the penguin amplitudes. This extends the knowledge of these next-to-next-to-leading-order contributions in the QCD factorization formula for B decays to a much wider class of final states, including all pseudoscalar-pseudoscalar, pseudoscalar-vector, and longitudinally polarized vector-vector final states, except final states with eta or eta' mesons. The new 1-loop correction is significant for the colour-suppressed amplitudes, but…
We present the next-to-leading order (NLO) electroweak (EW) corrections to the top quark pair production associated with a hard photon at the current and future hadron colliders. The dependence of the leading order (LO) and NLO EW corrected cross sections on the photon transverse momentum cut are investigated. We also provide the LO and NLO EW corrected distributions of the transverse momentum of final top quark and photon and the invariant mass of top quark pair and top-antitop-photon system. The results show that the NLO EW corrections are significant in high energy regions due to the EW Sud…
The computation of the NLO-QCD corrections to the cross sections for W γγproduction in hadronic collisions is presented. We consider the case of real photons in the final state, but include full leptonic decays of the W. Numerical results for the LHC and the Tevatron are obtained through a parton level Monte Carlo based on the structure of the VBFNLO program, allowing an easy implementation of general cuts and distributions. We show the dependence on scale variations of the integrated cross sections and provide evidence of the fact that NLO QCD corrections strongly modify the LO predictions fo…
The associated production of top-antitop-bottom-antibottom quarks is a relevant irreducible background for Higgs boson analyses in the top-antitop-Higgs production channel, with Higgs decaying into a bottom-antibottom quark pair. We implement this process in the PowHel event generator, considering the bottom quarks as massive in all steps of the computation which involves hard-scattering matrix-elements in the 4-flavour number scheme combined with 4-flavour Parton Distribution Functions. Predictions with NLO QCD + Parton Shower accuracy, as obtained by PowHel + PYTHIA, are compared to those wh…
The high luminosity that will be accumulated at the LHC will enable precise differential measurements of the hadronic production of a top--antitop-quark pair in association with a $\text{W}$ boson. Therefore, an accurate description of this process is needed for realistic final states. In this work we combine for the first time the NLO QCD and electroweak corrections to the full off-shell $\text{t}\overline{\text{t}}{\text{W}}^+$ production at the LHC in the three-charged-lepton channel, including all spin correlations, non-resonant effects, and interferences. To this end, we have computed the…
By using a Non-linear Electroweak Chiral Lagrangian, including the Higgs, coupled to heavy quarks, and the Equivalence Theorem, we compute (in the regime $M_t^2/v^2\ll\sqrt{s}M_t/v^2\ll s/v^2$) the one-loop amplitudes $W^+W^-\to t\bar t$, $ZZ\to t\bar t$ and $hh\to t\bar t$ (to NLO in the effective theory). We calculate the scalar partial-wave helicity amplitudes which allow us to check unitarity at the perturbative level in both $M_t/v$ and $s/v$. As with growing energy perturbative unitarity deteriorates, we also introduce a new unitarization method with the right analytical behavior on the …
Precision tests of the Standard Model (SM) require not only accurate experiments, but also precise and reliable theoretical predictions. Triple vector boson production provides a unique opportunity to investigate the quartic gauge couplings and check the validity of the gauge principle in the SM. Since the tree-level predictions alone are inadequate to meet this demand, the next-to-leading order (NLO) calculation becomes compulsory. In this paper, we calculate the NLO QCD + NLO electroweak (EW) corrections to the $W^{\pm}ZZ$ productions with subsequent leptonic decays at the $14~{\rm TeV}$ LHC…
We simulate the hadroproduction of a top-antitop pair in association with a bottom-antibottom pair at 14 TeV LHC using the PowHel package. We use the generated events, stored according to the Les-Houches event format, to make predictions for differential distributions formally at the next-to-leading order (NLO) accuracy and we compare these to existing predictions accurate at NLO.
In this work we investigate the NLO QCD+EW corrections to the top quark pair production and their effects on the spin correlation coefficients and asymmetries at fixed-order top quark pair production and LO decay in the dilepton channel, within the narrow-width approximation. The spin correlations are implicitly measured through the lepton kinematics. Moreover we study the EW effects to the leptonic differential distributions. We find that the EW corrections to the $t \bar t$ production are within the NLO QCD theoretical uncertainties for the spin correlation coefficients and the leptonic asym…
We compute the production cross section of a top-antitop pair in association with a jet at hadron colliders at next-to-leading order accuracy matched with parton shower algorithms to make predictions at the hadron level. The parton shower allows for including the decay of the top quarks at the leading order accuracy. We use a framework based on three well established numerical codes, the POWHEG-BOX, used for the calculation of the cross section, HELAC, which generates the matrix elements for the Born-level, real emission and the virtual part, and finally a parton shower program, such as PYTHIA…
We present results of a computation of NLO QCD corrections to the production of an off-shell top--antitop pair in association with an off-shell $\text{W}^+$ boson in proton--proton collisions. As the calculation is based on the full matrix elements for the process $\text{p}\text{p}\to {\text{e}}^+ν_{\text{e}}\,μ^-\barν_μ\,τ^+ν_τ\,{\text{b}}\,\bar{\text{b}}$, all off-shell, spin-correlation, and interference effects are included. The NLO QCD corrections are about $20\%$ for the integrated cross-section. Using a dynamical scale, the corrections to most distributions are at the same level, while …
We make use of recent results in effective theory and higher-order perturbative calculations to improve the theoretical predictions of the QCD contribution to the top-quark pair production forward-backward asymmetry at the Tevatron. In particular, we supplement the fixed-order NLO calculation with higher-order corrections from soft gluon resummation at NNLL accuracy performed in two different kinematic schemes, which allows us to make improved predictions for the asymmetry in the $p\bar p$ and $t\bar t$ rest frames as a function of the rapidity and invariant mass of the $t\bar t$ pair. Further…
In this talk I present the total cross sections, accurate at the NLO in QCD, for rare Standard-Model hadroproduction processes involving multi-Higgs-boson, multi-electroweak-boson and multi-top-quark final states. The comparison between cross sections at the LHC and at a future circular hadronic collider with up to 100 TeV centre-of-mass energy is detailed. Results relevant to the hadronic production of five electroweak bosons, and of a top-antitop pair in association with an electroweak vector boson and two jets are presented here for the first time with NLO accuracy.
We present predictions for the production cross section of a Standard Model Higgs boson in association with a top-antitop pair at next-to-leading order accuracy using matrix elements obtained from the HELAC-Oneloop package. The NLO prediction was interfaced to the PYTHIA and HERWIG shower Monte Carlo programs with the help of POWHEG-Box, allowing for decays of massive particles, showering and hadronization, thus leading to final results at the hadron level.
The next-to-leading-order electroweak corrections to $pp\to l^+l^-/\barνν+γ+X$ production, including all off-shell effects of intermediate Z bosons in the complex-mass scheme, are calculated for LHC energies, revealing the typically expected large corrections of tens of percent in the TeV range. Contributions from quark-photon and photon-photon initial states are taken into account as well, but their impact is found to be moderate or small. Moreover, the known next-to-leading-order QCD corrections are reproduced. In order to separate hard photons from jets, both a quark-to-photon fragmentation…
Understanding the polarisation structure and providing precise predictions for multi-boson processes at the LHC is becoming urgent in the light of the upcoming run-3 and high-luminosity data. The CMS and ATLAS collaborations have already started using polarised predictions to perform template fits of the data, getting access to the polarisation of W and Z bosons. So far, only fully-leptonic decay channels have been considered in this perspective. The natural step forward is the investigation of hadronic decays of electroweak bosons. In this work, we compute NLO QCD corrections to the productio…
We consider soft gluon emission corrections to the production of a top-antitop pair in association with a Higgs boson at hadron colliders. In particular, we present a soft-gluon resummation formula for this production process and gather all elements needed to evaluate it at next-to-next-to-leading logarithmic order. We employ these results to obtain approximate next-to-next-to-leading order (NNLO) formulas, and implement them in a bespoke parton-level Monte Carlo program which can be used to calculate the total cross section along with arbitrary differential distributions. We use this tool to …
We present predictions for the production cross section of a Standard Model Z0-boson in association with a top-antitop pair at the next-to-leading order accuracy in QCD, matched with shower Monte Carlo programs to evolve the system down to the hadronization energy scale. We adopt a framework based on three well established numerical codes, namely the POWHEG-BOX, used for computing the cross section, HELAC-NLO, which generates all necessary input matrix elements, and finally a parton shower program, such as PYTHIA or HERWIG, which allows for including t-quark and Z0-boson decays at the leading …
We perform threshold resummation of soft gluon corrections to the total cross sections and the invariant mass distributions for production of a top-antitop quark pair associated with a heavy electroweak boson $V = W^+$, $W^-$ or $Z$ in $pp$ collisions at the Large Hadron Collider. The resummation is carried out at next-to-next-to-leading-logarithmic (NNLL) accuracy using the direct QCD Mellin space technique in the three-particle invariant mass kinematics. It is found that for the $t\bar t Z$ process the soft gluon resummation introduces significant corrections to the next-to-leading order (NL…
We reconsider the complete set of four-quark operators in the Weak Effective Theory (WET) for non-leptonic $ΔF=1$ decays that govern $s\to d$ and $b\to d, s$ transitions in the Standard Model (SM) and beyond, at the Next-to-Leading Order (NLO) in QCD. We discuss cases with different numbers $N_f$ of active flavours, intermediate threshold corrections, as well as the issue of transformations between operator bases beyond leading order to facilitate the matching to high-energy completions or the Standard Model Effective Field Theory (SMEFT) at the electroweak scale. As a first step towards a SME…
We calculate the $W^\pmγj + X$-production cross sections at next-to-leading order QCD for Tevatron and LHC collisions. We include leptonic decays of the $W$ to light leptons, with all off-shell effects taken into account. The corrections are sizable and have significant impact on the differential distributions.
We present the full NLO QCD corrections to the production of a W^+W^- pair in association with two jets in hadronic collisions, which is an important background to New Physics and Higgs boson searches. We include leptonic decays of the W-bosons with full spin correlations. We find NLO corrections of the order of 10% for standard cuts at the LHC. The scale dependence is considerably reduced by the NLO corrections.
We compute, for $t \bar t$ production at the LHC and at the Tevatron, several charge asymmetries to NLO QCD, including also the electromagnetic and weak-interaction corrections. We calculate these asymmetries both inclusively and with additional kinematic cuts and compare our results, where possible, with recent experimental results and with SM predictions. The $t \bar t$ asymmetries induce also corresponding asymmetries for the charged leptons from semileptonic top-quark decay. Although these asymmetries are, in the SM, smaller than the corresponding ones for top quarks, they are expected to …
In various extensions of the Standard Model (SM) tree level non-leptonic decays of hadrons receive contributions from new heavy gauge bosons and scalars. Prominent examples are the right-handed W' bosons in left-right symmetric models and charged Higgs (H^\pm) particles in models with extended scalar sector like two Higgs doublet models and supersymmetric models. Even in the case of decays with four different quark flavours involved, to which penguin operators cannot contribute, twenty linearly independent operators, instead of two in the SM, have to be considered. Anticipating the important r…
We present the NLO QCD corrections to the production of a W+W- pair and two b-jets, including the leptonic decays of the W bosons. Contributions from singly resonant and non-resonant top quarks are fully taken into account. We also discuss observables relevant for top quark mass measurements and top quark asymmetries.
