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

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

7:y

[math]y=\frac{p\cdot q}{p\cdot k}=\frac{\nu}{E_i}=\frac{E_i-E_f}{E_i}[/math]

8:W

The invariant mass of the final hadronic system

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

9:[math]Q^2[/math]

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

[math]Q^2\equiv -q^2[/math]

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

[math]q\equiv k_i-k_f[/math]

10:[math]\nu[/math]

This represents the energy loss between scattering electrons.

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

This can be written in the Lab frame as:

[math]\nu\equiv E_i-E_f[/math]

where E_i and E_{f are the initial and final electron energies.}

=Writing LUND files{| border=1 align=center

 |+ LUND Header

|-

 ! Column
 ! Quantity

|-

|

1

|

Index

|-

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2

|

Charge

|-

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3

|

Type (1 is active)

|-

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4

|

Particle ID

|-

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5

|

Parent Index

|-

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6

|

Daughter Index

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7

|

Momentum x (GeV)

|-

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8

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Momentum y (GeV)

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9

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Momentum z (GeV)

|-

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10

|

[math]E[/math]

|-

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11

|

Mass

|-

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12

|

Vertex x (cm)

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13

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Vertex y (cm)

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14

|

Vertex z (cm)

|}