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src/integral/two_point/function_2p_m1m2 [ Modules ]

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NAME

  Module function_2p_m1m2

USAGE

  use function_2p_m1m2

DESCRIPTION

  This module is used to compute the two-point function
  I_2(s,m1^2,m2^2)
  with/without Feynman parameters in n dimensions

OUTPUT

  This module exports the functions:
  * f2p_m1m2 -- a function for the computation of 
  two-point integrals
  with non-zero momentum and two masses: I2^n({zj})(s,m1^2,m2^2)
  with/without Feynman parameters, in n dimensions
  one of the masses can be zero
  massless case is already contained in generic_function_2p

  
  i2sm1m2: computes the scalar two point function
  where both propagators have nonzero mass: 
  I_2^n(s,m1^2,m2^2)

  i2sm1: computes the scalar two point function
  where only one propagator has nonzero mass: 
  I_2^n(s,m^2,0)

USES

  * precision (src/module/precision_golem.f90)
  * logarithme (src/module/z_log.f90)
  * sortie_erreur (src/module/sortie_erreur.f90)
  * function_2p0m_1mi (src/integrals/two_point/function_2p0m_1mi.f90)

src/integral/two_point/function_2p_m1m2/f2p_m1m2 [ Functions ]

[ Top ] [ Functions ]

NAME

  Function f2p_m1m2

USAGE

  real_dim4 = f2p_m1m2(s,msq1_r,msq2_r,par1,par2)
  complex_dim2 =  f2p_m1m2(s,msq1_c,msq2_c,par1,par2)

DESCRIPTION

  This function computes the 
  two point function in n dimensions
  with non-zero momentum and two massive propagators
  with up to two Feynman parameters in the numerator.
  It retuns an array of 4 reals / 2 complex corresponding to the real/imaginary
  part of the coefficient of the 
  1/epsilon term and the real/imaginary part of the 
  constant term.
  corresponds to eqs.(A.5),(A.7) in hep-ph/0504267
  note that for rank one A_j^{2,1}=MINUS I_2(j,...)

INPUTS

  * m1,m2 -- real/complex (type ki), the value of the masses
  * par1 -- an integer, the label of one Feynman parameter
  * par2 -- an integer, the label of the second Feynman parameter
  Note that par1,par2 are ordered internally, i.e.
  par1 <= par2, note also to use zero for par1, par2 
  if this Feynman parameter does not exist.
  Use the routine tri_int(t_in,t_out) to order the labels in the module 
  tri_croissant (src/module/tri.f90)

SIDE EFFECTS

  No side effect

RETURN VALUE

  An real/complex (type ki) array of rank 1 and shape 4/2 corresponding to 
  the real/imaginary part of the coefficient of the 1/epsilon term
  and the real/imaginary part of the constant term.

EXAMPLE

 light-like-momentum two point function without Feynman parameters 
 f2p_m1m2(s,m1sq,m2sq,0,0) 
 with one Feynman parameter in the numerator z_1 
 f2p_m1m2(s,m1sq,m2sq,0,1)
 with two Feynman parameters in the numerator z_2^2
 f2p_m1m2(s,m1sq,m2sq,2,2) 
 with two Feynman parameters in the numerator z1*z_2
 f2p_m1m2(s,m1sq,m2sq,1,2)