cc.redberry.physics.feyncalc

Class PassarinoVeltman

java.lang.Object

cc.redberry.physics.feyncalc.PassarinoVeltman

public final class PassarinoVeltman
extends Object

Author:

Stanislav Poslavsky

Method Summary

Methods

Modifier and Type	Method and Description
static cc.redberry.core.tensor.Expression	generateSubstitution(int order, cc.redberry.core.tensor.SimpleTensor loopMomentum, cc.redberry.core.tensor.SimpleTensor[] externalMomentums) Generates a substitution for tensor integral reduction via Passarino-Veltman method.
static cc.redberry.core.tensor.Expression	generateSubstitution(int order, cc.redberry.core.tensor.SimpleTensor loopMomentum, cc.redberry.core.tensor.SimpleTensor[] externalMomentums, cc.redberry.core.transformations.Transformation simplifications) Generates a substitution for tensor integral reduction via Passarino-Veltman method.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

generateSubstitution

public static cc.redberry.core.tensor.Expression generateSubstitution(int order,
                                                      cc.redberry.core.tensor.SimpleTensor loopMomentum,
                                                      cc.redberry.core.tensor.SimpleTensor[] externalMomentums)

Generates a substitution for tensor integral reduction via Passarino-Veltman method. Note: the performance is limited for a large order or large number of external momentums.

Parameters:

order - power of loop momentum (q_i - 1, q_i*q_j - 2 etc.)

loopMomentum - loop momentum

externalMomentums - list of external momentums

Returns:

substitution in the form like q_i*q_j = p1_i * p2_j * C1 + ...

generateSubstitution

public static cc.redberry.core.tensor.Expression generateSubstitution(int order,
                                                      cc.redberry.core.tensor.SimpleTensor loopMomentum,
                                                      cc.redberry.core.tensor.SimpleTensor[] externalMomentums,
                                                      cc.redberry.core.transformations.Transformation simplifications)

Generates a substitution for tensor integral reduction via Passarino-Veltman method. Note: the performance is limited for a large order or large number of external momentums.

Parameters:

order - power of loop momentum (q_i - 1, q_i*q_j - 2 etc.)

loopMomentum - loop momentum

externalMomentums - list of external momentums

simplifications - additional simplification rules (e.g. Mandelstam substitutions for products of external momentum)

Returns:

substitution in the form like q_i*q_j = p1_i * p2_j * C1 + ...