TABLE OF CONTENTS
/formfactors_A_piMinus_proton [ Modules ]
NAME
module formfactors_A_piMinus_proton
PURPOSE
This module formfactors_A reads in the form factors for gamma* N -> N pi out of text files and includes modules to return the form factors as functions of theta, s and Q^2.
For the isospin channel gamma n -> p pi^-.
INPUTS
None
formfactors_A_piMinus_proton/getA_piMinus_proton [ Functions ]
[ Top ] [ formfactors_A_piMinus_proton ] [ Functions ]
NAME
function getA_piMinus_proton(thetaIn,sIn,QSquaredIn)
PURPOSE
This function returns the invariant Amplitudes A_1, ... A_6 of the MAID analysis.
INPUTS
- real :: thetaIn ! Theta scattering angle of the pion relative to q in the CM system of the hadronic vertex
- real :: QSquaredIn ! Q^2=-q^mu q_mu of the gamma
- real :: sIn ! Mandelstam s of the hadronic vertex: gamma* N-> pi N
OUTPUT
complex, dimension(1:6) :: getA ! The complex amplitudes A_1 to A_6 in units of:
- [GeV**-2] for A(1)
- [GeV**-4] for A(2) and A(5)
- [GeV**-3] for A(3), A(4) and A(5)
getA_piMinus_proton/get_i [ Functions ]
[ Top ] [ getA_piMinus_proton ] [ Functions ]
NAME
integer function get_i(tin,Win,Qin,int_nint_switch)
PURPOSE
Evaluates index which corresponds to the grid point which lies closest to the input values:
- For int_nint_switch=.false. it's the overall closest point
- For int_nint_switch=.true. it's the closest point which is also in all dimensions closer to 0 than the input point.
getA_piMinus_proton/get_neighbors [ Functions ]
[ Top ] [ getA_piMinus_proton ] [ Functions ]
NAME
function get_neighbors(tin,Win,Qin)
PURPOSE
Returns the eight grid points which are defining the smallest cube in which the input point (tin,win,Qin) can be locked into. These are the neighboring grid-points of our input point.
OUTPUT
integer,dimension(1:8) :: get_neighbors
getA_piMinus_proton/init_datFile [ Functions ]
[ Top ] [ getA_piMinus_proton ] [ Functions ]
NAME
subroutine init_datFile
PURPOSE
Reads in the MAID input file, writes into FF_A.dat the control output. It expects an input file with the following format:
- first some comment lines (doesn't matter how many)
- Data lines with the following order : W, ThetaCM , Q^2 ,s ,t, Re(A_1), Im(A_1),...Re(A_6), Im(A_6)
The loop structure to generate this input file should be :
- thetaCM-Loop, W-Loop, Q^2-Loop
OUPTUT Initializes the fields:
- complex, save , dimension(:,:), Allocatable :: A
- real, save , dimension(:) , Allocatable :: W, theta, Q2, s, t
- real,save :: W_max, theta_max, q2_max ! maximaal values for W,theta,q^2
- real, save :: dW,dTheta,dQ2 ! steps size for W,theta,q^2
- integer, save :: numSteps_q,numSteps_t,numSteps_w ! number of different values for q^2,theta, w