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The Organizers09/09/2019, 09:00
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Simone Amoroso (Deutsches Elektronen-Synchrotron (DE))09/09/2019, 09:15
This talk reviews experimental results of the ATLAS and CMS collaborations at the LHC, comprising SM, Top and Higgs measurements
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Prof. Aude Gehrmann-De Ridder (ETH Zurich)09/09/2019, 10:00
In this talk, I aim to review the phenomenology of LHC observables, related to processes newly implemented in the NNLOJET parton level event generator.
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Prof. Gang Yang09/09/2019, 11:00
The discovery of a standard-model-like Higgs boson at LHC set a milestone in particle physics. For probing potential new physics beyond the Standard Model as well as understanding the details of Higgs physics, the high precision computation of Higgs amplitudes is mandatory. We obtain the two-loop Higgs plus three-parton amplitudes with high dimension operators in Higgs effective field theory....
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Einan Gardi (The University of Edinburgh)09/09/2019, 11:30
Recently, there has been significant progress in computing scattering amplitudes in the high-energy limit using rapidity evolution equations. I describe the state-of-the-art and demonstrate the interplay between exponentiation of high-energy logarithms and that of infrared singularities.
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The focus in this talk is the imaginary part of 2 to 2 partonic amplitudes, which can be determined by... -
Massimiliano Grazzini (Universitaet Zuerich (CH))09/09/2019, 12:00
We consider the extension of the CMW soft-gluon effective coupling beyond the next-to-leading logarithmic accuracy. We present two proposals of a soft-gluon effective coupling that extend the CMW coupling to all perturbative orders. Although both effective couplings are well-defined in four dimensions, we examine their behaviour in d=4-2epsilon dimensions. We uncover an all-order perturbative...
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Ben Page (IPhT, CEA-Saclay)09/09/2019, 14:30
Scattering amplitudes in supersymmetric theories are known to display many remarkable structures, but most higher loop results are limited to planar theories. In this talk we discuss the structure of the recent, symbol-level, results for the N=4 SYM amplitude with full colour dependence and the N=8 SUGRA amplitude. We elaborate on the modern, ansatz-based, approach to the calculation. Leading...
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Prof. HuaXing Zhu09/09/2019, 15:00
We present an operator based factorization formula for the transverse energy-energy correlator (TEEC) hadron collider event shape in the back-to-back (dijet) limit. This factorization formula exhibits a remarkably symmetric form, being a projection onto a scattering plane of a more standard transverse momentum dependent factorization. Soft radiation is incorporated through a dijet soft...
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Sandro Uccirati (INFN - National Institute for Nuclear Physics)09/09/2019, 15:30
I present the complete results of "Torino" local analytic subtraction of infrared divergences from final state real radiation at NNLO in QCD and report the progresses for the analogous treatment of the radiation from the initial state.
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Alexander Penin (University of Alberta)09/09/2019, 16:00
We discuss nonfactorizable QCD corrections to Higgs boson production in vector boson fusion at the Large Hadron Collider. We point out that these corrections can be computed in the eikonal approximation retaining all the terms that are not suppressed by the ratio of the transverse momenta of the tagging jets to the total center-of-mass energy. Our analysis shows that in certain kinematic...
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Stefan Weinzierl (Universität Mainz)09/09/2019, 17:00
I will discuss Feynman integrals, which are associated to elliptic curves and their differential equations. I will show for non-trivial examples how the system of differential equations can be brought into an $\varepsilon$-form. Single-scale and multi-scale cases will be discussed.
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Tiziano Peraro09/09/2019, 17:30
I will describe FiniteFlow, a framework for defining and executing numerical algorithms over finite fields and reconstructing analytically multivariate rational functions. The framework employs computational graphs, known as dataflow graphs, to combine basic building blocks into complex algorithms. This allows to easily implement a wide range of methods over finite fields in high-level...
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Dr Dmitry Chicherin (Max Planck Institute for Physics)09/09/2019, 18:00
As the experimental precision at the LHC keeps improving,
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next-to-next-to leading order (NNLO) corrections for scattering processes have become crucial for providing theoretical predictions of comparable accuracy. At present, only observables involving up to four particles are available at this order. The main bottleneck towards higher multiplicity observables is the analytic calculation of... -
Dr Prasanna K. Dhani (INFN, Florence)09/09/2019, 18:30
I will talk about the recent computation of three loop jet functions (arXiv:1805.02637) in perturbative QCD. These results have been extracted from the known three loop coefficient functions for deep-inelastic scattering via the exchange of a virtual photon that couples to quarks or a scalar that couples to gluons and employing renormalization group invariance and factorization theorem. We...
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Dr Xuan Chen (Universitaet Zuerich (CH))10/09/2019, 09:00
Fiducial differential cross sections are reliable observables that the LHC is providing more and more precise measurements. From the theory point of view, event generators could simulate the underlying processes and apply the same experimental selection criterion to reduce the systematical errors when comparing with data. I will introduce some of the implementations and simulations from...
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Andreas von Manteuffel (Michigan State University)10/09/2019, 09:00
In this talk I will discuss new algorithmic approaches to reduce Feynman integrals. Syzygies derived in the Lee-Pomeransky and the Baikov representation allow to find linear relations, which avoid the introduction of either irreducible numerators or higher powers of propagators, respectively. The relevant syzygies can be calculated with linear algebra methods based on finite fields. These...
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Jos Vermaseren10/09/2019, 09:30
As part of a project to derive parametric reduction schemes automatically a
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systematic search has been set up to determine 'good sets of variables'. It
turns out that both the ease of derivation of a scheme and its efficiency
depend very sensitively on the choice of variables. For some topologies
there can be thousands of such choices. I report here on this search and
the resulting... -
Simone Devoto (UZH)10/09/2019, 09:30
The study of top-quark production and decay is central in the LHC physics programme, allowing precise tests of the Standard Model and offering a window on possible new physics. Accurate theoretical predictions are crucial for these analyses. In this talk, we report on a new calculation of the next-to-next-to-leading order QCD radiative corrections to the production of top-quark pairs at hadron...
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Vasily Sotnikov (University of Freiburg)10/09/2019, 10:00
We present the analytic form of all two-loop five-parton helicity amplitudes required for the calculation of NNLO QCD corrections to the production of three jets at hadron colliders in the leading-color approximation. The results are analytically reconstructed from exact numerical evaluations over finite fields. We employ a number of physics-motivated ideas to facilitate the reconstruction, as...
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Dr Narayan Rana (INFN Milan)10/09/2019, 10:00
In this talk, we outline the computational details to obtain mixed EW-QCD corrections to on-shell production of a single vector boson at the LHC at two-loop level. We use the novel method of differential equation to obtain the pure virtual, real-virtual and double-real master integrals.
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Ulrich Schubert10/09/2019, 11:00
After the discovery of the Higgs boson the precise determination of its properties has become a priority. These precision studies often involve the decay of the Higgs boson to bottom quarks, since it is the predominately decay channel. In this talk I will present the calculation of the exact mixed EW-QCD corrections to this decay, which improves upon the existing approximate calculation. In...
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Franz Herzog (Nikhef)10/09/2019, 11:00
The R*-method is a powerful tool to calculate anomalous dimensions of local QFTs. I will present new results which have been obtained with the method, such as the first few Mellin moments of splitting functions at N4LO, which also allowed us to obtain a first numerical estimate of the cusp anomalous dimension at five loops, and a calculation of the anomalous dimension of Weinberg's...
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Mr Amlan Chakraborty (The Institute of Mathematical Sciences, HBNI, Taramani, Chennai-600113, India)10/09/2019, 11:30
In this talk, we present a detailed study on the infrared structure of N=4 SYM and its connection to QCD. Calculation of collinear splitting functions helps to understand the structure and thus one can get infrared safe cross sections. We also demonstrate the factorization property that soft plus virtual part of the cross section satisfies and through factorization, we calculate soft...
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Matthias Heller10/09/2019, 11:30
The Drell-Yan production of charged lepton pairs is one of the key processes measured at hadron colliders. The QCD corrections to the cross-section are known to order $\alpha_s^2$ and electroweak corrections are known to order $\alpha$. The next important step for a better theoretical understanding is the complete calculation of the mixed QCD-EW corrections of order $\alpha_s \alpha$. In this...
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Ignacio Fabre (ICAS-UNSAM)10/09/2019, 12:00
When computing perturbative corrections to a process QCD provides the phenomenologically most significant contribution. Nevertheless, because of the similar size of $\alpha_S^2$ respect to $\alpha_{QED}$, for a precision prediction one needs to consider electroweak corrections as well.
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In this talk we show how one can obtain the mixed QCDxQED corrections from pure QCD NNLO corrections by... -
Rene Poncelet (Cambridge University)10/09/2019, 12:00
Precise predictions for total and differential cross sections
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at hadron colliders became an important corner stone of the LHC physics.
The lack of new 'smoking-gun' physics signals
requires precise comparisons between measurements and Standard Model
predictions to get a
handle on new physics effects. Tremendous efforts have been made to push
perturbative calculations to higher orders... -
Luca Buonocore (INFN - National Institute for Nuclear Physics)10/09/2019, 14:30
qT subtraction represents a well established and successful formalism to deal with the computation of QCD radiative corrections up to NNLO (and beyond) for a large class of processes relevant at the LHC. We have explored the possibility to extend qT subtraction to the computation of EW corrections with the (final) aim to develop a subtraction formalism suitable for the computation of mixed...
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Anna Kulesza10/09/2019, 14:30
The studies of the associated production processes of a top-quark pair with a colour-singlet boson, e.g. Higgs, W or Z, are among the highest priorities of the LHC programme. Correspondingly, improvements in precision of theoretical predictions for these processes are of central importance. In this talk, we review the latest results on resummation of soft gluon corrections. The resummation is...
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Lars-Thorben Moos10/09/2019, 15:00
The inlusive radiative $\bar{B}\rightarrow$ $X_s \gamma$ decay constitutes an important pillar in the indirect search for new physics and allows to constrain the parameter space of many models.
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In this talk we present the ongoing efforts in the computation of four-body contributions to the process $\bar{B}\rightarrow$ $X_s \gamma$, namely those of $b\ \rightarrow s\bar{q}q\gamma$ at NLO in the... -
Calum Milloy (University of Edinburgh)10/09/2019, 15:00
We discuss the relation between the infrared singularities of on-shell partonic form factors and parton distribution functions (PDFs) near the elastic limit, through their factorisation in terms of Wilson-line correlators. Ultimately we identify the difference between the anomalous dimension controlling single poles of these two quantities to all loops in terms of the closed parallelogram...
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Tobias Huber (University of Siegen)10/09/2019, 15:30
I will present the calculation of and results for the two-loop penguin amplitudes appearing in non-leptonic B-decays in the framework of QCD Factorisation. I will discuss the details of the computation of this genuine two-loop, two-scale problem, focusing i) on the analytic computation of the master integrals and ii) on the (partially analytic) convolution of the hard kernel with the...
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Melissa van Beekveld (R)10/09/2019, 15:30
Cross-sections in perturbative QCD are plagued by large corrections from soft and collinear radiation. The most singular terms are known to be universal, which allows their resummation to all orders in the coupling. In our work, we have examined the structure of the next-to-singular contributions, which can originate from the emission of both soft quarks and gluons. In this talk, I will show...
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Abdur Rehman (KIT, NCP (PK))10/09/2019, 16:00
The inclusive radiative decay of the B meson is known to provide strong constraints on new particles and their interactions. The current experimental world average for its branching ratio is $(3.32 \pm 0.15) \cdot 10^{-4}$ which agrees within one sigma with the present SM prediction $(3.36 \pm 0.23) \cdot 10^{-4}$. Some of the NNLO QCD corrections are included with the help of interpolation in...
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Mr Jort Sinninghe Damsté (University of Amsterdam)10/09/2019, 16:00
In QCD, soft radiation plays an important role in kinematic regions where resulting threshold logarithms become large. In this talk, I address such effects beyond leading power in the threshold expansion, for both fixed order and resummed results. For the double-real single-virtual correction to Drell-Yan, a large class of next-to-leading power (NLP) threshold logarithms is shown
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to be... -
Dr Ambresh Shivaji (IISER Mohali)10/09/2019, 17:00
Independent Measurements of Higgs self-couplings are crucial to probe new physics effects in the Higgs sector. Gluon fusion is the dominant mode for double Higgs production at hadron colliders. At leading order it is sensitive to the trilinear Higgs self-coupling. At higher orders in electroweak theory, it also becomes sensitive to the quartic coupling. We present a sensitivity study on the...
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Max Zoller (UZH)10/09/2019, 17:00
Recently, we published the OpenLoops 2 program, a powerful tool for the automation of NLO QCD and NLO EW calculations for all relevant LHC processes with high numerical stability in hard regions as well as in soft and collinear regions. This not only allows for highly efficient and accurate NLO calculations, but also for the numerically stable computation of NNLO real-virtual contributions....
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Gudrun Heinrich (Max Planck Institute for Physics)10/09/2019, 17:30
We show how anomalous trilinear Higgs boson couplings, as well as other anomalous couplings in the Higgs sector, impact the shapes of distributions in Higgs boson pair production. In particular we discuss the interplay between higher order QCD corrections and effects from physics beyond the Standard Model, parametrized by Effective Field Theory. We present new methods, partly based on machine...
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Prof. Jadach Stanislaw (IFJ PAN, Kraków)10/09/2019, 17:30
The expected experimental precision of the rates and asymmetries
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in the Future Circular Collider with electron positron beams (FCC-ee)
in the energy range 88-365GeV considered for construction in CERN,
will be better by a factor 5-200.
This will be thanks to very high luminosity,
factor up to $10^5$ higher than in the past LEP experiments.
This poses the extraordinary challenge of... -
Prof. Ravindran Vajravelu (The Institute of Mathematical Sciences)10/09/2019, 18:00
We present NNLO QCD corrections to production of pair of
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Higgs bosons in bottom quark annihilation at the Large Hadron Collider.
We take into account all the partonic channels in five flavour scheme.
We find that these corrections are important for the reliable predictions
which are less sensitive to unphysical scales. -
Kay Schönwald (DESY)10/09/2019, 18:00
At $e^+ \, e^-$ colliders the QED--initial state radiation forms a large part of the radiative corrections. Their
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precise and fast evaluation is an essential asset for the experiments at LEP, the ILC and the FCC-ee, operating at
high luminosity. A long standing problem in the analytic understanding of the $\mathcal{O}(\alpha^2)$ initial state
radiation is the observed discrepancy between... -
Manoj Kumar Mandal11/09/2019, 09:00
The reduction of a large number of scalar multi-loop integrals to the smaller set of Master Integrals is an integral part of the computation of any multi-loop amplitudes. The reduction is usually achieved by employing the traditional Integral-By-Parts (IBP) relations. However, in case of integrals with large number of scales, this quickly becomes a bottleneck. In this talk, I will show the...
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Vitalii Maheria11/09/2019, 09:00
Among the unitarity cuts of massless 4-loop propagators two classes remain unknown: 2-loop 3-particle, and 1-loop 4-particle cuts. I'd like to fill this gap and present the calculation of master integrals for both of these cuts. I would also like to discuss the ongoing work of using those to compute semi-inclusive phase-space integrals relevant to the calculation of NNLO time-like splitting functions.
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James Matthew (University of Edinburgh)11/09/2019, 09:30
It is known that one-loop Feynman integrals possess an algebraic structure encoding their analytic properties called the coaction, which can be written in terms of Feynman integrals and their cuts. This diagrammatic coaction, and the coaction on other classes of integrals such as hypergeometric functions, may be expressed using suitable bases of differential forms and integration contours....
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Martin Beneke (Technische Universitaet Muenchen (DE))11/09/2019, 09:30
A well-known result states that operators that vanish by the classical equation of motion do not mix into physical operators. The result guarantees that the S-matrix is invariant under large classes of field redefinitions. It is shown that (and why) the theorem is violated in soft-collinear effective theory beyond the leading power in the soft-collinear expansion. The mixing of eom operators...
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Dr Hjalte Axel Frellesvig (University of Padova)11/09/2019, 10:00
When finding linear relations between Feynman integrals using integration-by-parts identities, a very large linear system has to be solved as an intermediate step.
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This makes other approaches to the derivation of these identities a worthwhile pursuit. In this context, the concept of the intersection number is of interest, as it allows for the definition of (what amounts to) a scalar product... -
Robert Szafron (TU München)11/09/2019, 10:00
In this talk, I am going to report on the resummation of the leading logarithmic corrections for the Drell-Yan production and Higgs production in gluon fusion at the next-to-leading power in threshold expansion. I will describe how the kinematic power-corrections are accounted for and the structure of renormalisation group equations for the generalised soft function which appears after...
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Christian Sturm11/09/2019, 11:00
The effective field theory approach to general relativity allows to
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apply techniques for computing Feynman diagrams used in high energy
physics in order to calculate the gravitational two-body potential. In the
talk I will discuss the first-time calculation of the static two-body
potential to fifth post-Newtonian order. These results were achieved
thanks to a manifest factorization... -
Johann Kuehn11/09/2019, 11:00
Recent results concerning Higgs- and Z-boson decay rate
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in order alpha**4 and the five-loop beta-function are presented. -
Peter Marquard (DESY)11/09/2019, 11:30
We present new results for heavy quark form factors at three loop order.
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Mao Zeng (UC Los Angeles)11/09/2019, 11:30
We compute the third-post-Minkowskian conservative Hamiltonian of binary black holes using modern tools from scattering amplitudes and effective field theory. In the limit of large separation, non-spinning black holes have an effective description in terms scalar field particles coupled to gravity. The two-loop integrand is constructed using generalized unitarity and the double copy...
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Robert Schabinger11/09/2019, 12:00
In this talk, we discuss our ongoing calculation of the four-loop form factors of massless QCD. In particular, we present results for the quark and gluon form factors which we have calculated for the first time using novel computational techniques.
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Dr Andreas Maier (DESY)11/09/2019, 12:00
Higher-order corrections to the interaction potential between non-relativistic massive objects can be obtained systematically in a Post-Newtonian expansion in the small velocity and weak coupling. We present the calculation of these corrections up to five loops using techniques from multi-loop computations in high-energy physics.
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Dr Oleksandr Tomalak (University of Kentucky)11/09/2019, 12:30
Elastic neutrino-electron scattering provides an important tool for normalizing neutrino flux in modern experiments. This process is subject to large radiative corrections. We determine the Fermi effective theory performing the one-loop matching to the Standard model at the electroweak scale with subsequent running down to GeV scale. Based on this theory, we analytically evaluate virtual...
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Matthias Kerner (University of Zürich)11/09/2019, 12:30
I will present NLO corrections to Higgs boson production in association with a jet, retaining the full dependence on the top quark mass. Details of the calculation will be presented, focusing on the evaluation of the two-loop integrals, which is done numerically with the program SedDec. In particular I will present various improvements to the code, which have been achieved since the first...
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Alexander Manashov (Hamburg University)12/09/2019, 09:00
The B-meson distribution amplitude is defined by the matrix element of a heavy-light quark operator between the vacuum and B-meson states. The scale dependence of the corresponding DA is governed by the renormalization group equation for this operator. At one loop the corresponding evolution kernel was derived by Lange and Neubert. I'll argue that the form of the kernel is strongly restricted...
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Dr Matteo Becchetti (Center for Cosmology, Particle Physics and Phenomenology (CP3), Univeritè Catholique de Louvain )12/09/2019, 09:00
We present the analytic calculation of the Master Integrals for certain two-loop, non-planar topologies that enter the calculation of the amplitude for top-quark pair hadroproduction in the quark-annihilation channel. These Master Integrals are needed to complete the evaluation of the two color factors in the quark-annihilation channel which are not yet known analytically at two-loop. We...
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Dr Goutam Das (DESY)12/09/2019, 09:30
We present a factorisation formula for the double differential cross-section in the N-jettiness variables τ1 and τ0. The phase space spanned by these two variables are already known in different hierarchies between them. However the region τ1 ~ τ0 is not well known due to absence of a proper factorisation formula in this scenario....
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Valerio Casconi (Università La Sapienza)12/09/2019, 09:30
In this talk, I will present the analytic calculation of the planar master integrals for the two-loop light-fermion electroweak corrections for the production of a Higgs boson in the gluon-gluon fusion channel. The complete dependence on the electroweak boson mass is retained. The master integrals are evaluated by means of the differential equations method and the analytic result are expressed...
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York Schröder (UBB Chillán)12/09/2019, 10:00
Within finite-temperature quantum field theory, the evaluation of vacuum-type sum-integrals plays a central role in the determination of equilibrium observables, such as the free energy (or pressure) of a thermal system.
As has been repeatedly observed in the past, many two-loop sum-integrals can be decomposed into one-loop factors, allowing for analytic solutions in the space-time dimension...
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Mr Sebastian Jaskiewicz (Technical University of Munich)12/09/2019, 10:00
Soft Collinear Effective Theory (SCET) formalism has been successfully applied to a number of important observables in collider physics improving the accuracy of fixed-order predictions via the leading power resummation of large logarithmic contributions which appear in certain regions of phase space. Recently, a renewed interest in subleading power corrections has arisen in the theoretical...
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Carsten Schneider (RISC, Johannes Kepler University Linz)12/09/2019, 11:00
Recently, we have worked out how thousands of moments of Feynman integrals can be computed if they are represented by coupled systems of linear differential equations and sufficiently many initial values. Given these moments one is in the position to derive recurrence relations and to solve these recurrences, e.g., within the class of indefinite nested sums. In this talk we will present a...
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Xiaoran Zhao12/09/2019, 11:00
At hadron colliders, the leading production mechanism for a pair of photons is from quark-anti-quark annihilation at the tree level. However, due to large gluon-gluon luminosity, the loop-induced process $gg\to \gamma \gamma$ provides a substantial contribution. In particular, the amplitudes mediated by the top quark become important at the $t \bar t$ threshold and above. In this letter we...
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Malgorzata Worek (RWTH Aachen University )12/09/2019, 11:30
With the goal of increasing the precision of NLO QCD predictions for the pp->ttγ process in the di-lepton top quark decay channel we present theoretical predictions for the cross section ratio. Results for the latter together with various differential cross section ratios will be presented for the LHC Run II energy of 13 TeV. Fully realistic NLO QCD computations for both tt and ttγ production...
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Thomas Johannes Georg Rauh (Universität Bern)12/09/2019, 11:30
Gluon fusion processes like single and double Higgs production exhibit slow convergence and pose severe computational challenges. We show how the top-quark mass dependence of the virtual amplitudes can be reconstructed with a conformal mapping and Padé approximants based on the expansion in the inverse top-quark mass and the non-analytic terms in the expansion around the top threshold. The...
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Tsuneo Uematsu (Kyoto University)12/09/2019, 12:00
Within the framework of the standard model as well as the two Higgs
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doublet model including the MSSM as a special case, we examine the
CP-even and CP-odd Higgs boson production in electron-photon collisions.
We particularly emphasize the role of the transition form factor
in terms of which the production amplitudes can be given. -
Michael Borinsky (Nikhef)12/09/2019, 12:00
Recently, there have been remarkable advances concerning the systematic integration of higher loop Feynman amplitudes. A synthesis of differential equation and number theoretical methods can be employed to calculate position space Feynman amplitudes in the massless case. The combination of these two methods makes this approach very efficient, as an IBP reduction step can be bypassed. We will...
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Dr Zoltán Szőr (Mainz University)12/09/2019, 14:30
Relating loop integrals to tree level objects goes back several decades to Feynman. In the past ten years the loop-tree duality theorem was introduced, which expresses $l$-loop integrals in terms of phase space integrals of sum of trees obtained from cutting $l$ internal propagators of the loop graph. In addition, the uncut propagators gain a modified $i \delta$-prescription, named dual...
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Bakul Agarwal (Michigan State University)12/09/2019, 14:30
In this talk, we discuss top quark contributions to ZZ production through gluon fusion at two loops. We use a syzygy based approach for the reductions to master integrals. In order to numerically evaluate the amplitude, we express it in terms of finite integrals, which we construct out of linear combinations of divergent integrals using a new algorithm.
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Dr William Javier Torres Bobadilla (IFIC CSIC-UV)12/09/2019, 15:00
In order to make predictions that can be compared with the results that the LHC delivers, there are several approaches to compare the experiment with the theory. It is known that to establish this comparison, we cannot rely on leading order (LO) calculations only. Hence, we need to consider next-to-leading order (NLO) contributions, that are often understood as virtual and real. Although we...
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Prakash Mathews12/09/2019, 15:00
We compute the two-loop massless QCD corrections to the four point amplitude
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g + g -> A + A. Two operators contribute this amplitude and the ultraviolet renormalisation requires careful treatment involving mixing. The universal structure of the infrared poles are studied in detail. -
Roberto Pittau (Universidad de Granada (ES))12/09/2019, 15:30
I discuss the latest developments of FDR in the context of Quantum Field Theory calculations relevant for High Energy Physics phenomenology. In particular, I focus on NNLO computations and the use of FDR in connection to effective QFTs.
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Dr Taushif Ahmed (Max-Planck-Institut für Physik)12/09/2019, 15:30
Productions of the Higgs boson in association with a massive vector boson, i.e. the VH events, play an important role in the explorations of Higgs physics at the LHC, both for a precise study of Higgs' Standard Model couplings and for probing new physics. In this talk, we present the 2-loop massless QCD corrections to the helicity amplitudes of the associated Higgs production through the...
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Ansgar Denner (Julius Max. Universitaet Wuerzburg (DE))12/09/2019, 16:00
The proper renormalization of mixing angles in quantum field theories
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is a long-standing problem. It is relevant for the renormalization of the
quark mixing matrix in the Standard Model and for various mixing
scenarios in theories beyond. In this talk we specifically consider
theories with extended scalar sectors. We review existing renormalization
schemes for mixing angles and introduce... -
Pulak Banerjee (Paul Scherrer Institut)12/09/2019, 16:00
In this talk, I present the computation of the two loop massless QCD corrections to the four-point amplitude $g + g → H + H$ (arXiv:1809.05388) resulting from effective operator insertions that describe the interaction of a Higgs boson with gluons in the infinite top quark mass limit. This amplitude is an essential ingredient to the third-order QCD corrections to Higgs boson pair production....
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Andrea Quadri (INFN, Sez. di Milano)12/09/2019, 17:00
The consistent recursive subtraction of UV divergences order by order in the loop expansion for spontaneously broken effective gauge theories with higher dimension derivative operators is presented. The Slavnov-Taylor identity is solved to all orders in the loop expansion by homotopy techniques and a suitable choice of invariant field coordinates (named bleached variables) for the linearly...
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Prof. Johannes Bluemlein (DESY)12/09/2019, 17:00
Recent results are presented on polarized and unpolarized heavy flavor corrections
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to DIS to 2- and 3-loop order in the full region and for large virtualities.
In the polarized case we also discuss the treatment of \gamma_5 and derive
results in the M-scheme. -
Scott Alan Yost (The Citadel - The Military College of South Carolina (US)), Scott Yost (The Citadel)12/09/2019, 17:30
KKMC-hh is a precision event generator for Z boson production at a hadron collider, based on coherent exclusive exponentiation (CEEX) of soft photon emission at the amplitude level. We will summarize studies of ISR and IFI effects on calculations AFB for precision EW analysis at the LHC. Different approaches to ISR will be compared, and progress will be reported on implementing NLO QCD in KKMC-hh.
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Jean-Loic Kneur (Univ. Montpellier)12/09/2019, 17:30
Our renormalization group consistent version of optimized perturbation, RGOPT, had been used to calculate the nonperturbative QCD spectral density of the Dirac operator and the related chiral quark condensate $\langle \bar q q \rangle$, for $n_f=2$ and $n_f=3$ massless quarks. Sequences of approximations at two-, three-, and four-loop orders gave stable parameter-free determinations...
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Maria Vittoria Garzelli (Universita e INFN, Firenze (IT))12/09/2019, 18:00
In this talk I will present open issues in the deacription of processes leading to the hadroproduction of at least one heavy meson or baryon, considering different flavour number schemes. Solving these issues is important for improving the accuracy of PDf fits and of predictions in high-energy astroparticle physics.
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Bennie Ward (Baylor University (US))12/09/2019, 18:00
IR-improvement based on amplitude-level resummation allows one to control unintegrable results in quantum field theory with arbitrary precision in principle. We illustrate such resummation in specific examples in precision LHC and FCC physics and in quantum gravity.
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12/09/2019, 18:30
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Ruth Britto (Trinity College Dublin)13/09/2019, 09:00
Feynman integrals that have been evaluated in dimensional regularization can be written in terms of generalized hypergeometric functions. It is well known that properties of these functions are revealed in the framework of intersection theory. We propose further applications of intersection theory in the case of functions associated to positive geometries, in particular to construct a...
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Matthias Steinhauser (KIT)13/09/2019, 09:30
In this talk we discuss NNLO and N3LO order corrections
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to the process gg->HH in the Standard Model. In particular,
we consider three-loop corrections to the form factors entering the virtual
corrections in the large-mt
limit and compute five expansion terms.
In the same approximation we also evaluate the
real radiation corrections at NNLO. Finally, we present
a building block for the... -
Maximilian Stahlhofen (JGU Mainz)13/09/2019, 10:00
The cusp anomalous dimension is a universal and ubiquitous quantity in QCD. It governs the IR structure of scattering amplitudes and is the key ingredient to (Sudakov) resummation for high-energy collider processes. I will report on recent analytic results on the matter dependence of the cusp anomalous dimension at four loops and discuss the calculational methods used to obtain them.
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Mikhail Solon13/09/2019, 11:00
We combine tools from the modern amplitudes program and effective field theory to develop a systematic and scalable method for deriving classical dynamics for binary systems from on-shell scattering. Applying this to gravitationally interacting massive scalars yields the first derivation of the conservative Hamiltonian for compact spinless binaries at third post-Minkowskian order. The...
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Mr Roberto Mondini (University at Buffalo)13/09/2019, 11:30
We present a fully-differential calculation of the $H \to b\overline{b}$ decay at next-to-next-to-next-to-leading order (N3LO) accuracy. Our calculation considers diagrams in which the Higgs boson couples directly to the bottom quarks. In order to regulate the infrared divergences present at this order we use the Projection-to-Born technique coupled with N-jettiness slicing. After validating...
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Long Chen (Max Planck Institute for Physics)13/09/2019, 12:00
We present a calculation of the NLO QCD corrections to the loop-induced production of a photon pair through gluon fusion, including massive top quarks at two loops, where the two-loop integrals are calculated numerically. Matching the results for the virtual amplitude to a threshold expansion, we obtain accurate results around the top quark pair production threshold. We analyse how the top...
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Dr Stefano Laporta (University of Padova)13/09/2019, 12:30
I this talk I will show the result of the 1100-digits calculation of the 4-loop QED contribution to the first derivative of the Dirac form factor at zero momentum transfer. An analytical fit has been obtained, and I will describe its structure. I will discuss also the contribution of this result to the Lamb shift of hydrogen.
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