Description
"Calculations for Modern and Future Colliders" satellite workshop
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Konstantin Chetyrkin (Karlsruhe Institute of Technology)23/07/2015, 14:30We discuss the current status of the ongoing analytical calculation of the QCD beta-function in 5 loops as well as some new results in investigating CBK (Crewther-Brodhurst-Kataev) relation in QCD. The latter include the evaluation of the new singlet type contribution to the Bjorken sum rule (first considered by Larin) which appears first at 4-loop level only. We will also report on the...Go to contribution page
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Andrey Grozin (urn:Google)23/07/2015, 15:00The three-loop cusp anomalous dimension $\Gamma$ has been calculated analytically, as a function of the Minkowski angle $\phi$, via harmonic polylogarithms up to weight 5. The color structures $C_F (T_F n_f)^{L-1} \alpha_s^L$ in $\Gamma$ and the HQET quark field anomalous dimension have been obtained to all orders. At large $\phi$ the coefficient of $1/(1-z)_+$ in the DGLAP evolution kernel...Go to contribution page
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Dr Andrei Kataev (Institute for Nuclear Reserch of the Russian Academy of Sciences)23/07/2015, 15:30The current knowledge on the three-loop approximation of the static potential in QCD is reviewed . The results are used for the determination of the 4-th order approximation of the QCD $\beta$-function and for the $e^+e^-$-annihilation R-ratio in the V-scheme. The results are compared with the ones obtained in the $\overline{MS}$-scheme and minimal MOM scheme in the Landau gauge. The...Go to contribution page
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Mikhail Kompaniets (St. Petersburg State University (RU))23/07/2015, 16:20Using R* operation, IBP and integration of hyperlogarithms (HyperInt) we perform 6 loop calculation of beta function in $\phi^4$ model. One of the remarkable features of this result is that 6 loop term contains multiple zeta values. We discuss different aspects of this calculations as well as series resummation and predictions for 6 loop term based on Kazakov/Shirkov/Tarasov (1979) paperGo to contribution page
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Dr Alexander Bednyakov (JINR)23/07/2015, 16:50Two-loop electroweak corrections to the decoupling relations between the running $\overline{MS}$ parameters of the SM and their counterparts in the effective five-flavour QCDxQED theory are considered for the strong coupling constant $\alpha_s(\mu)$ and the bottom-quark mass $m_b(\mu)$ . The decoupling procedure is outlined and the numerical impact of the obtained terms are discussed.Go to contribution page
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Andrey Pikelner (BLTP JINR)23/07/2015, 17:10We present our progress in calculation of four-loop beta-functions in the SM. The results for the strong coupling is obtained in the gaugeless limit. Pure QCD part coincides with known expressions. The method of calculation and validation of the result are discussed.Go to contribution page
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Anton Trunin (Joint Institute for Nuclear Research)23/07/2015, 17:30On the basis of perturbative QCD and relativistic quark model we calculate cross sections of pair pseudoscalar and vector $B_c$ mesons production in proton--proton interaction. Relativistic factors in the production amplitude connected with the relative motion of heavy quarks and the transformation law of the bound state wave function are taken into account. The gluon and quark propagators...Go to contribution page
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Dr Vladimir Smirnov (SINP MSU)24/07/2015, 14:30Evaluating Feynman integrals by uniformly transcendental differential equationsGo to contribution page
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Roman Lee (Budker Institute of Nuclear Physics)24/07/2015, 15:00Recently a remarkable observation was made concerning differential equation system for multiloop integrals. It appeared that in many cases by the proper choice of functions the differential system can be represented in the form where the dependence on regularization parameter is reduced to an overall factor $\epsilon$ in the right-hand side. Such a representation makes finding general...Go to contribution page
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Alexander Smirnov (Moscow State University)24/07/2015, 15:30In modern elementary particle physics one often needs to evaluate millions of Feynman integrals. An already classical approach is to apply the so-called integration by parts relations and reduce all integrals to a smaller set, the master integrals. We present FIRE5 - a powerful program performing Feynman integral reduction.Go to contribution page
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Dr Oleg Tarasov (JINR)24/07/2015, 16:20New methods for deriving functional equations for Feynman integrals are proposed. Several examples of functional equations for two-loop integrals are considered in detail. Application of functional equations for analytic continuation of Feynman integrals considered in arbitrary space-time dimension is demonstrated.Go to contribution page
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Dmitry Vlasenko (Southern Federal University)24/07/2015, 16:40The SYM theory in higher dimensions, namely D=6,8,10 cases were considered. The main interest is UV divergence of the theory, basically leading pole behavior. Based on calculation of some first loops an iterative procedure which allows to predict leading poles in each order without its direct calculation were constructed. Using this procedure a set of equations which provides a possibility to...Go to contribution page
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Dr Andrei Davydychev (SINP MSU and Schlumberger)24/07/2015, 17:00Different representations for the three-body phase space are considered, exploring their symmetry properties and geometrical meaning. We derive expressions that are explicitly symmetrical in the masses of the three particles. We study geometrical properties of the variables involved in elliptic integrals and demonstrate that it is convenient to use the Jacobian zeta function to express the...Go to contribution page
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Dr César Ayala (Department of Theoretical Physics and IFIC, University of Valencia and CSIC, E-46100, Valencia, Spain)24/07/2015, 17:20We investigate a novel non-perturbative QCD running coupling motivated by confinement and asymptotic freedom. This coupling is formulated in terms of a gluon mass function analogous to that of Dyson-Schwinger approaches. We calculate the corresponding potential à la Richardson and are able to reproduce the Cornell potential. The resulting gluon mass is close to the Dyson-Schwinger parameter.Go to contribution page
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Victor Kim (St. Petersburg Nuclear Physics Institute - PNPI, Gatchina)26/07/2015, 14:30Brief overview of searches for BFKL-evolution manifestations at high energies is presented. Data comparison with the predictions of BFKL-evolution in the leading logarithm (LL) and next-to-leading logarithm (NLL) approximations are discussed.Go to contribution page
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Andrey Kataev (INR RAS)26/07/2015, 15:00We discuss generalizations of the Brodsky–Lepage–Mackenzie optimization procedure for renormalization group invariant quantities. In this respect, we discuss in detail the features and construction of the {β}-expansion presentation instead of the standard perturbative series with regard to the Adler D- function and Bjorken polarized sum rules S obtained in the order of $O(α_s^4)$. Based on the...Go to contribution page
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Vladimir Saleev (Samara State University)26/07/2015, 15:30An overview of recent results (2010-2015) obtained in the Parton Reggeization Approach (PRA) are presented. The dominance of multi-Regge final states in particle production at high energies needs the kt-factorization (high-energy factorization) approach for description of hard hadron-hadron collisions instead of the collinear approximation of the conventional Parton Model. The Lipatov's...Go to contribution page
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Alexandera Shipilova (Samara State University, Samara State Aerospace University)26/07/2015, 16:20We study inclusive azimuthal decorrelations in jet, b-jet and D-meson pair production in proton-proton collisions at the CERN LHC invoking the hypothesis of parton Reggeization in t-channel exchanges at high energies. Using a high-energy factorization scheme with the Kimber-Martin-Ryskin unintegrated parton distribution functions and the Fadin-Lipatov effective vertices we obtain good...Go to contribution page
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Mr Maxim Nefedov (Samara State University)26/07/2015, 16:40The hadroproduction of prompt isolated photon pairs at high energies is studied in the NLO* framework of the Parton Reggeization Approach. The real part of the NLO corrections is computed, and the procedure for the subtraction of double counting between real parton emissions in the hard-scattering matrix element and unintegrated PDF is constructed for the amplitudes with Reggeized quarks in...Go to contribution page
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Igor Cherednikov (University of Antwerp)26/07/2015, 17:00We address several unresolved issues in the QCD-based description of the three-dimensional inner structure of the nucleon accessible in the current and planned high-energy experiments. The emphasis is placed on the comparison of existing perturbative resummation methods and corresponding evolution equations (DGLAP, BFKL, CCFM, SCET etc.) for transverse-momentum dependent parton distribution...Go to contribution page
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Oleg Veretin (University of Hamburg, II. Theoretical Institute)26/07/2015, 17:20We study the relationships between the basic parameters of the on-shell renormalization scheme and their counterparts in the $\overline{\mathrm{MS}}$ scheme at full order $\mathcal{O}(\alpha^2)$ in the Standard Model. These enter as threshold corrections the renormalization group analyses underlying, e.g., the investigation of the vacuum stability. To ensure the gauge invariance of the...Go to contribution page
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Dr Mikhail Dolgopolov (Samara State University)27/07/2015, 14:30The development of the catastrophe theory methods is proposed for the effective Higgs type potentials stability conditions. The role of temperature effective loop corrections and the temperature evolution of phase transitions in some advanced two-doublet models are considered.Go to contribution page
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Mr Sergey Volkov (SINP MSU, Dubna)27/07/2015, 15:00A "forest-like" subtraction scheme is proposed for removal both ultraviolet and infrared divergences in Feynman amplitudes. This scheme is developed especially for QED calculation of the anomalous magnetic moment. The procedure gives a finite Feynman-parametric integral for any Feynman diagram (at any order of perturbation), so we don't need any regularization. The subtraction scheme is...Go to contribution page
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Luca Panizzi (University of Southampton)27/07/2015, 15:30New heavy quarks are predicted in various scenarios of new physics; depending on their nature they can mix with SM quarks or they can even mediate the production of dark matter states. Theoretically-motivated scenarios of new physics in general predict the existence of multiple new quarks with different couplings with the SM states or dark matter. Experimental searches of new quarks at...Go to contribution page
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Dr Grigory Pivovarov (Russian Academy of Sciences (RU))27/07/2015, 16:20Two existing approaches to the evolution of the scalar mass are discussed. In particular, their opposite implications for the naturalness problem are pointed out. Next, a possibility of an alternative approach to computing the renormalization group evolution of the standard model parameters is discussed. Within this approach, the naturalness problem may be moved to a high energy scale which...Go to contribution page
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Andrei Onishchenko27/07/2015, 16:40We will describe the methods and techniques used both to perform and automate calculations of quarkonia production at NLO accuracy. We will also present some preliminary results for the case of pair production.Go to contribution page
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Alexander Ochirov (University of Edinburgh)27/07/2015, 17:00We explore implications of the color-kinematics duality for quantum chromodynamics with massive quarks. We work out a decomposition n-point tree amplitudes in a small basis of color-ordered "primitive'' amplitudes, using general properties of color and kinematics. First, we decompose the full scattering amplitude with 2k quarks and (n-2k) gluons in terms of the Melia basis, which consists of...Go to contribution page
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Dr Anton Baushev (Observatotio Cerro Calan, Departamento de Astronomia, Universidad de Chile, Santiago, Chile)27/07/2015, 17:20The question of the density profile of dark matter halos is extremely important for various topics of the dark matter physics. In principle, it can shed light on the physical nature of the dark matter. Now the contradiction between the standard dark matter paradigm and observations seems obvious. The main aim of the talk is to discuss the ways to agree theory with observations. We show that...Go to contribution page
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Ms Gayatri Ghosh (Physics Department, Gauhati University)27/07/2015, 17:40Using the results from LHC on Higgs mass, we present limits on Lepton Flavor Violation(LFV), in SUSY SO(10) theories. We have used Dirac Neutrino Yukawa Couplings as calculated in such theories. We have presented our results using different models like NUHM, mSUGRA, NUGM. We have compared our results with latest data from MEG experiment on charged lepton flavor violation. Latest results from...Go to contribution page
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Ringaile Placakyte (Deutsches Elektronen-Synchrotron (DE))28/07/2015, 14:30The uncertainties of protons parton distribution functions (PDFs) play a dominant role for the precision tests of the Standard Model (SM) and they also impact substantially the theory predictions of Beyond SM high mass production. We present the HERAFitter project which provides a unique open-source software framework for the determination of the proton's PDFs and for the interpretation of...Go to contribution page
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Andrey Sapronov (Joint Inst. for Nuclear Research (RU))28/07/2015, 15:00The report presents new features of the MCSANC program, a Monte Carlo tool for calculation of the next-to-leading order electroweak and QCD corrections to various Standard Model processes. The extensions concern implementation of the Drell-Yan-like processes and include systematic treatment of the photon-induced contribution in proton-proton collisions and electroweak corrections beyond...Go to contribution page
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Thomas Luebbert (University of Hamburg)28/07/2015, 15:30qT spectra of massive bosons at hadron colliders provide important tests of the Standard Model. In the crucial region, where the boson's invariant mass M is much smaller than its transverse momentum qT, the spectra are very sensitive to initial state radiation. Applying soft-collinear effective theory, a universal framework for its description has been established and the relevant...Go to contribution page
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Mr Nikolay Krasnikov (INR, Moscow)28/07/2015, 16:20We review the phenomenology and the experiments on the search for light vector boson. The existence of the additional light vector boson was proposed for the explanation of the (g-2) muon anomaly.Go to contribution page
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Yahor Dydyshka (Byelorussian State University (BY))28/07/2015, 16:40We present strategy for optimization of the scattering amplitude calculation using Clifford algebra. Application to the one-loop tensor integral reduction is demonstrated.Go to contribution page
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Vitaly Yermolchyk (Byelorussian State University (BY))28/07/2015, 17:00We present the Monte Carlo event generator *LePaProGen* for neutral and charged current Drell-Yan processes, which is intended for accurate and fast generation of events taking in account higher-order radiative corrections. We introduce some new physical algorithms and code features like independent algorithm for the optimal selection of variables for phase-space parametrization.Go to contribution page
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Mark Sutton (University of Sussex (GB))28/07/2015, 17:20Recent developments in the fast reproduction of the results of QCD calculations using the APPLgrid project are presented. The calculation of cross-sections at Next-to-Leading order in QCD involves the integration over the final state phase space in order to cancel the infra-red divergences. For the calculation of cross sections for observables at hadron-hadron colliders this...Go to contribution page
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Dr Alexander Nesterenko (Joint Institute for Nuclear Research)29/07/2015, 14:30The dispersive approach to QCD is applied to the study of the hadronic vacuum polarization function and associated quantities. This approach merges the intrinsically nonperturbative constraints, which originate in the kinematic restrictions on the respective physical processes, with corresponding perturbative input. The obtained hadronic vacuum polarization function agrees with pertinent...Go to contribution page
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Tord Riemann (DESY)29/07/2015, 15:00The Z boson line shape can be studied with unprecedented precision at certain future e+e- collider projects. For example, the Fcc-ee might produce 10^13 Z bosons. This will demand for true two-loop calculations in the Standard Model, and even higher precision in the QED part. As alternative, sophisticated model-independent approaches are welcome. I discuss questions related to both theoretical...Go to contribution page
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Dr Anatoly Kotikov (BLTP JINR)29/07/2015, 15:30I will review the results for master integrals having the property of maximal transcendentality.Go to contribution page
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Dr Sergey Larin (INR RAS, Moscow)29/07/2015, 16:20The QCD Lagrangian is modified by adding gluon masses to ensure the agreement of the theory with experiments. On mass-shell renormalizability of the resulting model is demonstrated.Go to contribution page
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Dr Vladimir Zykunov (BelSUT)29/07/2015, 16:40A method for taking into account radiative events with hard photon emission in experiments aimed at studying Moller scattering with polarized particles was developed. A computer code used to perform a numerical analysis with allowance for the kinematical conditions of the MOLLER experiment at the Jefferson Lab was constructed. The respective results were compared with their counterparts...Go to contribution page
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Dr Inna Serenkova (Gomel State Technical University)29/07/2015, 17:00The prospects of discovery and identification of large extra spatial dimensions effects in the process of lepton and photon pair production at the Large Hadron Collider (LHC) were studied. These effects can be found by the specific behavior of the invariant mass distributions of the lepton and photon pairs. Identification of the effects under study can be performed with angular...Go to contribution page