We present new theoretical predictions for the tt̄ production cross section at NNLO at the Tevatron and the LHC. We discuss the scale uncertainty and the errors due to the parton distribution functions (PDFs). For the LHC, we present a fit formula for the pair production cross section as a function of the center of mass energy and we provide predictions for the pair production cross section of a hypothetical heavy fourth generation quark t′.

In this article, we present a new implementation of the Laporta algorithm to reduce scalar multi-loop integrals---appearing in quantum field theoretic calculations---to a set of master integrals. We extend existing approaches by using an additional algorithm based on modular arithmetic to remove linearly dependent equations from the system of equations arising from integration-by-parts and Lorentz identities. Furthermore, the algebraic manipulations required in the back substitution are optimized. We describe in detail the implementation as well as the usage of the program. In addition, we show benchmarks for concrete examples and compare the performance to Reduze 2 and FIRE 5. In our benchmarks we find that Kira is highly competitive with these existing tools.

We present the calculation of the next-to-leading order QCD corrections for top-quark pair production in association with an additional jet at hadron colliders, using the modified minimal subtraction scheme to renormalize the top-quark mass. The results are compared to measurements at the Large Hadron Collider run I. In particular, we determine the top-quark running mass from a fit of the theoretical results presented here to the LHC data.

We discuss theoretical predictions for the production of five hard jets at next-to-leading order accuracy QCD at the Large Hadron Collider. Results are shown for both the total cross section as well as for differential distributions of the jet transverse momenta and rapidities. As a general pattern, we find moderate corrections of the order of 10% with respect to the LO result and a significant reduction of the scale dependence. Furthermore, ratios of different jet-multiplicity are studied. Our results are compared with data from the ATLAS collaboration.

We present updated predictions for single top-quark production in hadronic collisions. The analysis is based on next-to-leading order QCD calculations. The input parameters are fixed to recent measurements. We compare different PDF sets and investigate the related uncertainties. The impact of uncalculated higher orders is estimated using an independent variation of the renormalisation and factorisation scale. The theoretical predictions are compared with recent measurements from Tevatron and LHC. Furthermore, the cross section measurements are used to estimate the top-quark mass. To perform the analysis we extended the publicly available HatHor program to single top-quark production. We thus provide a unified framework for the fast numerical evaluation of total cross sections for top-quark production, which may be used for example in Standard Model fits. For future extensions towards NNLO accuracy, we include already all scale dependent terms at NNLO. We briefly describe how to use the program and provide all required tools to repeat the aforementioned analysis.

A comprehensive review of physics at an [Formula: see text] linear collider in the energy range of [Formula: see text] GeV-3 TeV is presented in view of recent and expected LHC results, experiments from low-energy as well as astroparticle physics. The report focusses in particular on Higgs-boson, top-quark and electroweak precision physics, but also discusses several models of beyond the standard model physics such as supersymmetry, little Higgs models and extra gauge bosons. The connection to cosmology has been analysed as well.

A comprehensive review of physics at an \(e^+e^-\) linear collider in the energy range of \(\sqrt{s}=92\) GeV–3 TeV is presented in view of recent and expected LHC results, experiments from low-energy as well as astroparticle physics. The report focusses in particular on Higgs-boson, top-quark and electroweak precision physics, but also discusses several models of beyond the standard model physics such as supersymmetry, little Higgs models and extra gauge bosons. The connection to cosmology has been analysed as well.

In this article we discuss the calculation of single top-quark production in the t channel at two-loop order in QCD. In particular we present the decomposition of the amplitude according to its spin and colour structure and present complete results for the two-loop amplitudes in terms of master integrals. For the vertex corrections compact analytic expressions are given. The box contributions are implemented in a publicly available C program.

This report summarizes the proceedings of the 2014 Mainz Institute for Theoretical Physics (MITP) scientific program on "High precision fundamental constants at the TeV scale". The two outstanding parameters in the Standard Model dealt with during the MITP scientific program are the strong coupling constant α_s and the top-quark mass m_t. Lacking knowledge on the value of those fundamental constants is often the limiting factor in the accuracy of theoretical predictions. The current status on α_s and m_t has been reviewed and directions for future research have been identified.

We present an update of the Binoth Les Houches Accord (BLHA) to standardise the interface between Monte Carlo programs and codes providing one-loop matrix elements.

In these proceedings we report our progress in the development of the publicly available C++ library NJet for accurate calculations of high-multiplicity one-loop amplitudes. As a phenomenological application we present the first complete next-to-leading order (NLO) calculation of five jet cross section at hadron colliders.

A new method to measure the top-quark mass in high energetic hadron collisions is presented. We use theoretical predictions calculated at next-to-leading order accuracy in quantum chromodynamics to study the (normalized) differential distribution of the \(t\bar{t} + 1\mbox{-jet}\) cross section with respect to its invariant mass \(\sqrt{s_{t\bar{t} j}}\). The sensitivity of the method to the top-quark mass together with the impact of various theoretical and experimental uncertainties has been investigated and quantified. The new method allows for a complementary measurement of the top-quark mass parameter and has a high potential to become competitive in precision with respect to established approaches. Furthermore we emphasize that in the proposed method the mass parameter is uniquely defined through one-loop renormalization.

In this talk I discuss the importance of precise top-quark mass determinations. Some conceptual aspects of top-quark mass measurements as well as methods used/proposed in the past are presented. In addition an entirely new method, which has been proposed very recently by S. Alioli et al., is reviewed.

We present a new method to measure the top-quark mass in high energetic hadron collisions at the LHC. We study the mass dependence of the production of top-quark pairs in association with an additional jet. The cross section of tt+1Jet production is sensitive to the top-quark mass since gluon radiation depends on the top-quark mass through threshold and cone effects. In particular we study the normalised tt +1Jet cross section differential in the invariant mass of the final state jets. We have investigated the sensitivity of the method together with the impact of various theoretical and experimental uncertainties. We find that the method has the potential to be competitive with existing methods. We emphasize that in the proposed method the mass parameter can be uniquely defined through one-loop renormalization.

This work presents a new method to measure the top-quark mass in hadronic collisions[1]. The method uses the sensitivity of the tt¯+1$tar t + 1$-jet production on the top-quark mass. In detail we study the ℛ distribution defined as the tt¯+1$tar t + 1$-jet normalized cross section differential in the invariant mass of the total system and calculated at NLO accuracy. We prove that the ℛ distribution has a high sensitivity to the top-quark mass. Furthermore we investigate and quantify the impact of the dominant theoretical and experimental uncertainties. The results obtained show, that the method has the potential to be competitive in precision with established approaches and allows a complementary measurement of the top-quark mass at hadron colliders. We emphasize that in the proposed method the mass parameter is uniquely defined through one-loop renormalization.

We present a computer library for the numerical evaluation of colour-ordered n-gluon amplitudes at one-loop order in pure Yang-Mills theory. The library uses the recently developed technique of generalised unitarity. Running in double precision the library yields reliable results for up to 14 gluons with only a small fraction of events requiring a re-evaluation using extended floating point arithmetic. We believe that the library presented here provides an important contribution to future LHC phenomenology. The program may also prove useful in cross checking results obtained by other methods. In addition, the code provides a sample implementation which may serve as a starting point for further developments.Program summaryProgram title: NGluonCatalogue identifier: AEIZ_v1_0Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEIZ_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: GNU Public LicenseNo. of lines in distributed program, including test data, etc.: 30 677No. of bytes in distributed program, including test data, etc.: 334 896Distribution format: tar.gzProgramming language: C++Computer: Any computer platform supported by the GNU compiler suite.Operating system: No specific requirements - tested on Scientific Linux 5.2.RAM: Depending on the complexity, for realistic applications like 10 gluon production in double precision below 10 MB.Classification: 11.5External routines: QCDLoop (http://qcdloopfnal.gov/), qd (http://crd.lblgov/-dhbailey/mpdist/)Nature of problem: Evaluation of next-to-leading order corrections for gluon scattering amplitudes in pure gauge theory.Solution method: Purely numerical approach based on tree amplitudes obtained via Berends-Giele recursion combined with unitarity method.Restrictions: Running in double precision the number of gluons should not exceed 14.Running time: Depending on the number of external gluons between less than a millisecond (4 gluons) up to a 1 s (14 gluons) per phase space point. (C) 2011 Elsevier By. All rights reserved.