Ariadne

In DIS Ariadne uses Lepto or Pythia to generate the electro-weak subprocess and Jetset for fragmentation. In Photoproduction it uses Pythia for the hard subprocesses and Jetset for fragmentation.

Here is a list of parameters and switches in Ariadne which are important for DIS.

Parameters in common block /ARDAT1/

PARA(1) (Default = 0.22 GeV) lambda_QCD (tuned by LEP)
PARA(3) (0.6 GeV) p_t^cut (tuned by LEP)
PARA(10) (1) Power in soft suppression (dimensionality of proton remnant). Should be around one. Should not be larger than 2.
PARA(14) (1) Factor to multiply primordial k_t to get extension of the remnant (mu) also multiplies Q to get extension of struck quark. Should be of the order 1
PARA(15) (1) Power in soft suppression for struck quark. Should be around one. Should not be larger than 2.
PARA(25) (2) Governs the probability of having emissions outside the soft suppression cut-off. Only influence the high-p_t tail.
PARA(27) (0.6 GeV) Squared gives the mean value of primordial k_t^2. Should be below 1 GeV.

Switches in common block /ARDAT1/

MSTA(17) (Default = 3) Emit recoil gluons
0 no
3 yes
MSTA(34) (2) Inclusion of pomeron induced events
0 no
1-3 yes (Various options, please consult author)
MSTA(35) (0) Colour rearrangement
0 off
<>0 on (various options, please consult author)

Here is a sample program for generating DIS events with the Lepto+Ariadne+Jetset combination.

Leif Lönnblad