DV Creating LUND Files

The LUND format

LUND Header

Column	Quantity
1	Number of Particles
2	Number of Target Nucleons
3	Number of Target Protons
4	Target Polarization
5	Beam Polarization
6	x
7	y
8	W
9	[math]\displaystyle{ Q^2 }[/math]
10	[math]\displaystyle{ \nu }[/math]

Where

1:Number of Particles

This line tells how many particles follow the header line. For Moller Scattering, this number should always be 2.

2:Number of Target Nucleons

For this simulation, only an electron-electron collision is considered. This quantity is always set to 1 for the one stationary electron we consider the incident electron scattering from.

3:Number of Target Protons

For Moller Scattering, there are no target protons. This number is set to 1, but does not have any effect within the GEMC simulations.

4:Target Polarization

This represents the polarization of the target material, either positive or negative 1. This value is always set to 1 and has no effect within the GEMC simulations.

5:Beam Polarization

This represents the polarization of the electron beam, either negative or positive 1. This value is always set to positive 1.

6:x

This represents the Bjorken x scaling variable.

[math]\displaystyle{ x=\frac{-q^2}{2p\cdot q}=\frac{-q^2}{2M\nu} }[/math]

Where M is the rest mass-energy of the proton[math]\displaystyle{ M\approx 938MeV }[/math]

7:y

[math]\displaystyle{ y=\frac{p\cdot q}{p\cdot k}=\frac{\nu}{E}=\frac{E-E'}{E} }[/math]

8:W

The invariant mass of the final hadronic system

[math]\displaystyle{ W^2\equiv (p+q)^2=M^2+2M\nu+q^2=M^2+2M\nu-Q^2 }[/math]

9:[math]\displaystyle{ Q^2 }[/math]

This represents the squared 4-momentum-transfer vector q of the exchanged virtual photon.

[math]\displaystyle{ Q^2\equiv -q^2 }[/math]

Where q is the momentum transfer betwwn the incident electron and target via the virtual photon.

[math]\displaystyle{ q\equiv k_i-k_f }[/math]

10:[math]\displaystyle{ \nu }[/math]

This represents the energy loss between scattering electrons.

[math]\displaystyle{ \nu = \frac{p\cdot q}{M} }[/math]

This can be written in the Lab frame as:

[math]\displaystyle{ \nu\equiv E-E' }[/math]

where E and E' are the initial and final electron energies.