Conveners
Track 3: Computations in Theoretical Physics: Techniques and Methods: Parallel Session
- Stephen Jones (MPI, Munich)
Track 3: Computations in Theoretical Physics: Techniques and Methods
- Thomas Hahn (MPI f. Physik)
Track 3: Computations in Theoretical Physics: Techniques and Methods: Parallel Session
- Daniel Maitre
Track 3: Computations in Theoretical Physics: Techniques and Methods: Parallel Session
- Fukuko YUASA (KEK)
Track 3: Computations in Theoretical Physics: Techniques and Methods: Round table discussion
- Ayres Freitas (University of Zurich)
Track 3: Computations in Theoretical Physics: Techniques and Methods: Parallel Session
- Elise de Doncker (Western Michigan University)
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Ben Ruijl (Nikhef)21/08/2017, 14:00Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
We show how an extended version of the R* operation, a method to remove UV and soft IR divergences, can be used to calculate the poles of Feynman diagrams with arbitrary tensor structure from diagrams with fewer loops. We discuss solutions to combinatorial problems we encountered during the computation of the five loop QCD beta function, such as postponing Feynman rule substitutions, integral...
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Dr Stefano Laporta (Dipartimento di Fisica, Universita di Bologna)21/08/2017, 14:25Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
In this talk I will describe the results of evaluation up to 1100 digits of precision of the mass-independent contribution of the 891 4-loop Feynman diagrams contributing to the electron g-2 in QED.
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I will show the analytical expressions fitted to the high-precision values,
which contain polylogarithms of sixth-root of unity and one-dimensional integrals of products of complete elliptic... -
Dr Daniel Maitre (IPPP)21/08/2017, 14:50Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
The storage of computationally intensive matrix elements for NLO processes have proven a good solution for high-multiplicity processes. In this presentation I will present the challenges of extending this method to calculation at NLO and offer some ways of alleviating them.
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Xiaohui Liu (Beijing Normal University )21/08/2017, 15:15Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
In this talk, I will review the current status of N-jettiness subtraction scheme and its application to Vj production at the LHC.
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Dr Soon Yung Jun (Fermi National Accelerator Lab. (US))21/08/2017, 16:30Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
Simulation in high energy physics (HEP) requires the numerical solution of ordinary differential equations (ODE) to determine the trajectories of charged particles in a magnetic field when particles move throughout detector volumes. Each crossing of a volume interrupts the underlying numerical method that solves the equations of motion, triggering iterative algorithms to estimate the...
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Marcin Slodkowski (Faculty of Physics, Warsaw University of Technology (PL))21/08/2017, 16:55Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
This work is focused on the influence of energy deposited by jets in the
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medium on the behavior of bulk nuclear matter.
In the heavy ion reactions jets are widely used as probes in the study
of Quark-Gluon-Plasma (QGP). Modeling using relativistic hydrodynamics with
jets perturbation is employed to extract the properties of the QGP.
In order to observe a modification of the collective... -
Stefano Carrazza (CERN)21/08/2017, 17:20Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
Parton Distribution Functions (PDFs) are a crucial ingredient for accurate and reliable theoretical predictions for precision phenomenology at the LHC.
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The NNPDF approach to the extraction of Parton Distribution Functions relies on Monte Carlo techniques and Artificial Neural Networks to provide an unbiased determination of parton densities with a reliable determination of their... -
Ricardo Vilalta (University of Houston)21/08/2017, 17:45Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
The widespread dissemination of machine learning tools in science, particularly in astronomy, has revealed the limitation of working with simple single-task scenarios in which any task in need of a predictive model is looked in isolation, and ignores the existence of other similar tasks. In contrast, a new generation of techniques is emerging where predictive models can take advantage of...
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Andrei Davydychev (Moscow State University and Schlumberger)22/08/2017, 14:00Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
It is shown how the geometrical splitting of N-point Feynman diagrams can be used to simplify the parametric integrals and reduce the number of variables in the occurring functions. As an example, a calculation of the dimensionally-regulated one-loop four-point function in general kinematics is presented.
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Thomas Hahn (MPI f. Physik)22/08/2017, 14:25Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
Loopedia is a new database for bibliographic (and other) information on loop integrals. Its bibliometry is orthogonal to that of SPIRES or arXiv in the sense that it admits searching for graph-theoretical objects, e.g. a graph's topology. We hope it will in time be able to answer the query "Find all papers pertaining to graph $X$."
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Dr Hiren Patel (UMass Amherst)22/08/2017, 14:50Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
Package-X is a Mathematica package for analytically computing and symbolically manipulating dimensionally regulated one-loop Feynman integrals, and CollierLink is an upcoming interface to the COLLIER library. In this talk, I will review new features in the upcoming release of Package-X: calculation of cut discontinuities, and command-line readiness. Additionally, features of CollierLink will...
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Kiyoshi Kato (Kogakuin University)22/08/2017, 16:45Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
The direct computation method(DCM) is developed to calculate the multi-loop amplitude for general masses and external momenta. The ultraviolet divergence is under control in dimensional regularization.
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We discuss the following topics in this presentation.
From the last report in ACAT2016, we have extended the applicability of DCM to several scalar multi-loop integrals.
Also it will be shown... -
Elise de Doncker (Western Michigan University)22/08/2017, 17:10Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
Using lattice generators, we implement lattice rules in
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CUDA for a many-core computation on GPUs. We discuss a
high-speed evaluation of loop integrals, based on
lattice rules combined with a suitable transformation.
The theoretical background of the method and its
capabilities will be outlined. Extensive results have been
obtained for various rules and integral dimensions, and
for... -
Stephen Jones (MPI, Munich)22/08/2017, 17:35Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
We introduce pySecDec, a toolbox for the numerical evaluation of multi-scale integrals, and highlight some of the new features. The use of numerical methods for the computation of multi-loop amplitudes is described, with a particular focus on Sector Decomposition combined with Quasi-Monte-Carlo integration and importance sampling. The use of these techniques in the computation of multi-loop...
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Ayres Freitas (University of Pittsburgh)22/08/2017, 18:00Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
There are currently no analytical techniques for computing multi-loop integrals with an arbitrary number of different massive propagators. On the other hand, the challenge for numerical methods is to ensure sufficient accuracy and precision of the results. This contribution will give a brief overview on numerical approaches based on differential equations, dispersion relations and...
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Kiyoshi Kato (Kogakuin University), Stephen Jones (MPI, Munich), Takahiro Ueda (KEK), Walter Giele24/08/2017, 14:00Track 3: Computations in Theoretical Physics: Techniques and Methods
In recent years, we have seen an explosion of new results at the NNLO level and beyond for LHC processes. These advances have been achieved through both analytical and numerical techniques, depending on the process and the group that performed the calculation.
This panel discussion will address such as how much the minimization of computer running time is desirable and if the possibility to...
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Sebastien Binet (IN2P3/LPC)24/08/2017, 16:45Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
High Energy and Nuclear Physics (HENP) libraries are now required to be more and
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more multi-thread-safe, if not multi-thread-friendly and multi-threaded.
This is usually done using the new constructs and library components offered by
the C++11 and C++14 standards.
These components are however quite low-level (threads, mutexes, locks, ...) and
hard to use and compose, or easy to... -
Dr Hiroshi DAISAKA (Hitotsubashi University)24/08/2017, 17:10Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
Evaluation of a wide variety of Feynman diagrams with multi-loop integrals and physical parameters, and its comparison with high energy experiments are expected to investigate new physics beyond the Standard Model. We have been developing a direct computation method (DCM) of multi-loop integrals of Feynman diagrams. One of the features of our method is that we adopt double exponential (DE)...
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Dr Carlos Inostroza (Universidad de Concepcion)24/08/2017, 17:35Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
The contraction method is a procedure that allows to establish non-trivial relations between Lie algebras and has had successful applications in both mathematics and theoretical physics. This work deals with generalizations of the contraction procedure with a main focus in the so called S-expansion method as it includes most of the other generalized contractions. Basically, the S-expansion...
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Dr Carlos Inostroza (Universidad de Concepcion)24/08/2017, 18:00Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
S-expansion of Lie algebras is a procedure that contains the Inonu-Wigner contraction and most of its generalizations. Based on a recent work where we have presented a Java library to perform S-expansions of Lie algebras [arXiv:1703.04036] we provide an extension allowing to solve different problems. In particular, in this work we complement our library of [arXiv:1703.04036] with new...
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Renat Sadykov (Joint Institute for Nuclear Research (RU))Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
We continue to study Bhabha scattering at the one-loop level in SANC system. It is our first step to development EW library for radiative corrections
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for processes e+e−→ff¯ with longitudinal polarization for future collides. Higher-order leading logarithmic QED corrections are taken into account by means of structure function approach. Comparison with the existing results for unpolarized... -
Serguei Bityukov (Institute for High Energy Physics (RU))Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
The concept of "the significance of the difference" is widely used in data analysis in high-energy physics. We consider the significance Type C [1]. This significance is used in works [2,3,4]. It is shown that when comparing two independent samples obtained from one general population, the distribution of estimates of the "significance of the difference" for mean values, obtained for these...
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Track 3: Computations in Theoretical Physics: Techniques and MethodsOral
In this work, we present results obtained with the new Three-fluid Hydrodynamics-based Event Simulator Extended by UrQMD final State interactions (THESEUS) and apply it to the description of heavy-ion collisions in the NICA/FAIR energy range. It presents the 3FH output in terms of a set of observed particles and the afterburner can be run starting from this output by means of the UrQMD model....
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