ACAT 2011

Session

Monday 05th - Computations in Theoretical Physics

5 Sept 2011, 14:00

39. Three-Loop Calculation of the Higgs Boson Mass in Supersymmetry

Dr Philipp Kant (Humboldt-Universität zu Berlin)

05/09/2011, 14:00

Track 3: Computations in Theoretical Physics - Techniques and Methods

Parallel talk

A Key feature of the minimal supersymmetric extension of the Standard Model (MSSM) is the existence of a light Higgs boson, the mass of which is not a free parameter but an observable that can be predicted from the theory. Given that the LHC is able to measure the mass of a light Higgs with very good accuracy, a lot of effort has been put into a precise theoretical prediction. We...

3. Multiloop calculations in supersymmetric theories with the higher covariant derivative regularization

Dr konstantin stepanyantz (Moscow State University)

05/09/2011, 14:25

Track 3: Computations in Theoretical Physics - Techniques and Methods

Parallel talk

Most calculations of quantum correction in the supersymmetric theories are made with the dimensional reduction, which is a modification of the dimensional regularization. However, it is well known that the dimensional reduction is not self-consistent. A consistent regularization, which does not break the supersymmetry is the higher covariant derivative regularization. However, the integrals...

11. Regularization Schemes and Higher Order Corrections

William Kilgore (Brookhaven National Lab)

05/09/2011, 14:50

Track 3: Computations in Theoretical Physics - Techniques and Methods

Parallel talk

I apply commonly used regularization schemes to a multiloop calculation to examine the properties of the schemes at higher orders. I find complete consistency between the conventional dimensional regularization scheme and dimensional reduction, but I find that the four-dimensional helicity scheme produces incorrect results at next-to-next-to-leading order and singular results...

112. An analytical solution for a non-planar massive double box diagram

Mr Andreas von Manteuffel (University of Zurich)

05/09/2011, 15:15

Track 3: Computations in Theoretical Physics - Techniques and Methods

Parallel talk

An analytical calculation of a non-planar 2-loop box diagram is presented. This diagram appears in the computation of higher order corrections to top- quark pair production and contains one internal massive line. The corresponding integrals are solved with differential equation and Mellin-Barnes techniques.

38. SecDec: a tool for numerical multi-loop/leg calculations

Jonathon Carter (University of Durham)

05/09/2011, 16:10

Track 3: Computations in Theoretical Physics - Techniques and Methods

Parallel talk

Sector decomposition is a method to extract singularities from multi-dimensional polynomial parameter integrals in a universal way. Integrals of this type arise in perturbative higher order calculations in multi-loop integrals as well as in phase space integrals involving unresolved massless particles. The program 'SecDec' will be presented, which...

73. Regularization of IR-divergent loop integrals

Prof. Elise de Doncker (Western Michigan University)

05/09/2011, 16:35

Track 3: Computations in Theoretical Physics - Techniques and Methods

Parallel talk

We report results of a new regularization technique for infrared (IR) divergent loop integrals using dimensional regularization, where a positive regularization parameter (epsilon, satisfying that the dimension d = 4+2*epsilon) is introduced in the integrand to keep the integral from diverging as long as epsilon > 0. Based on an asymptotic expansion of the integral we construct a...

77. Different forms of the generalized Crewther relation in QCD and QED: concrete consequences of analytical multiloop calculations

Dr Andrei Kataev (INR, Moscow, Russia)

05/09/2011, 17:00

Track 3: Computations in Theoretical Physics - Techniques and Methods

Parallel talk

Different forms of the generalized Crewther relation in QED and QCD are discussed. They follow from applyication of the method of OPE to the AVV triangle amplitude in the limit when conformal symmetry is valid and broken by the prosedure of renormalizations in the various variants of MS scheme, including 't Hooft prescription for defining beta-function. Special features of the...

40. FormCalc 7

Thomas Hahn (MPI f. Physik)

05/09/2011, 17:25

Track 3: Computations in Theoretical Physics - Techniques and Methods

Parallel talk

The talk presents the new features in FormCalc 7 (and some in LoopTools), such as analytic tensor reduction, inclusion of the OPP method, and the interface to FeynHiggs.