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## /lorentzTrafo [ Modules ]

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NAME

module lorentzTrafo

PURPOSE

Implements lorentz transformation.

## lorentzTrafo/lorentzCalcBeta [ Functions ]

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NAME

function lorentzCalcBeta (Mom, CallName) result (beta) function lorentzCalcBeta (Mom, flagOK, CallName) result (beta) function lorentzCalcBeta (mom3, mass, CallName) result (beta)

PURPOSE

calculate the beta-Vector for a Lorentz-Boost. checks whether a valid vector results

INPUTS

• real,dimension(0:3) :: Mom
• character(40),optional :: CallName

or:

• real, dimension(1:3) :: mom3
• real :: mass
• character(40),optional :: CallName

RESULT

• real, dimension(1:3) :: beta
• logical :: flagOK -- indicates success (if given, code does not stop)

## lorentzTrafo/lorentz [ Subroutines ]

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NAME

subroutine lorentz(beta,fourVector,CallName)

PURPOSE

performs Lorentz transformation of fourVector into a system which is traveling with the velocity beta(1:3)

INPUTS

• real,dimension(0:3),intent(inout) :: fourVector
• real,dimension(1:3),intent(in) :: beta
• character(*),intent(in),optional :: CallName

RESULT

• real,dimension(0:3),intent(inout) :: fourVector

## lorentzTrafo/BoostTensor [ Subroutines ]

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NAME

subroutine BoostTensor(u,e,e0)

PURPOSE

Lorentz-Transformation of a tensor e(0:3,0:3) into a system moving with 4-velocity u(0,3).

INPUTS

• real,dimension(0:3),intent(in) :: u -- boost 4-velocity
• real,dimension(0:3,0:3),intent(in) :: e -- tensor in CF

RESULT

• real,dimension(0:3,0:3),intent(in) :: e0 -- tensor in LRF

NOTES

Lorentztransformation des Energie-Impuls-Tensor in das Ruhesystem

## lorentzTrafo/eval_sigmaBoost [ Functions ]

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NAME

real function eval_sigmaBoost(mom1,mom2)

PURPOSE

This function calculates the boost factor for a cross section. Given a cross section "sigma" which is defined the rest frame of particles A or B, the cross section "sigmaPrime" in a frame where both a moving is given by:

• sigmaPrime=sigma* eval_sigmaBoost

INPUTS

• real , dimension(0:3),intent(in) :: mom1,mom2 -- 4-momenta of the colliding pair

OUTPUT

• Boost factor

NOTES

• For derivation confer Oliver's Phd thesis (Appendix G)
• Note that the formula given in Effenberger's diploma thesis is only very approximate!!