ACAT 2008

Session

Methodology of Computations in Theoretical Physics - Session 1

3 Nov 2008, 14:00

Ettore Majorana Foundation and Centre for Scientific Culture

206. Unitarity Methods For 1-Loop Amplitudes

Warren Perkins (Swansea University UK)

03/11/2008, 14:00

3. Computation in Theoretical Physics

Parallel Talk

Unitarity methods provide an efficient way of calculating 1-loop amplitudes for which Feynman diagram techniques are impracticable. Recently several approaches have been developed that apply these techniques to systematically generate amplitudes. The 'canonical basis' implementation of the unitarity method will be discussed in detail and illustrated using seven point QCD processes.

180. From moments to functions in higher order QCD

Johannes Bluemlein (DESY)

03/11/2008, 14:25

3. Computation in Theoretical Physics

Parallel Talk

We present a method to unfold the complete functional dependence of single-scale quantities as QCD splitting functions and Wilson coefficients from a finite number of moments. These quantities obey recursion relations which can be found in an automated way. The exact functional form is obtained solving the corresponding difference equations. We apply the algorithm to the QCD Wilson...

56. Computational aspects for three-loop DIS calculations

Dr Mikhail Rogal (DESY)

03/11/2008, 14:50

3. Computation in Theoretical Physics

Parallel Talk

will be sent later

226. Recent developments of GRACE

Dr Yoshimasa KURIHARA (KEK)

03/11/2008, 15:15

3. Computation in Theoretical Physics

Parallel Talk

Automatic Feynman-amplitude calculation system, GRACE, has been extended to treat next-to-leading order (NLO) QCD calculations. Matrix elements of loop diagrams as well as those of tree level ones can be generated using the GRACE system. A soft/collinear singularity is treated using a leading-log subtraction method. Higher order re-summation of the soft/collinear correction by the parton...