All the physics generators for the mu beam programme are linked via this switch. To distinguish between them a second card has been prepared:

MUKIN N

Presently two options are available and a third is ready to be implemented.

• MUKINE 1 this is to read events from file (unit 25)
• MUKINE 2 this is to steer LEPTO production (DIS on Nucleons)
• MUKINE 3 this is to steer AROMA production (not yet ready)

External Files

Here you can read events from unit 25 written in LeptoDump format. In principle any LUND based generation can read via this mechanism (basically the LUJETS common is dumped in a compact form to disc; this allow at least interchange of files between IBM AIX - CernSP and SUN Solaris machines, maybe more). The routine to read/write are rdbevt.F and dmpevt.F (The first one is omgeant/omgbatch/ompro whilst for the second one ask Massimo Lamanna).

LEPTO

If the MUKIN card has benn set to two via the

 MUKIN 2

the following cards are used to prepare the appropriate setup for the Lepto generator (presently Lepto 6.3).

C
C Lepto Internal Event Generation
C
C Min/Max of bjorken x, y, Q^2 and nu (=E-E')
C
XLPT  0.1    0.999
YLPT  0.001  0.999
QLPT  1.0  100.0
VLPT 15.0 65.0
C ----1--2--3--4--5--6--7--8--9-10-11-12-13-14--15-16-17-18-19-20--------LST--*
LST   2  1  5  1  3  1  1 12  5  1 111 3  3  4 5007 2  0  2  1  1
C ----1---2---3---4---5---6---7---8----9--10-----------------------------PARL-*
PARL 2.  1. .44 .75 .226 0.  0. 1.5E-2 2.0 0. 
C ---11-------12--13---14-----15----16-------17-------18-----19----20----PARL-*
      1.0E-2 4.0 0.1 0.44 1.0E-2 7.2974E-3 1.1664E-5 4.4E-2 3.0E-2 1.0

The first 4 cards determine the ranges of x bjorken, y, Q^2 (in GeV2) and nu (=E'-E in GeV) where the generation will take place. Since these variables are not independent, the intersection of all ranges is taken; if the intersection is too small the program can crash at initialization with no clear message from Lepto. LST and PARL are use to select target type, distribution function and many other parameters. Please refer to the LEPTO manual to set up these.

Note also that the lepton type and its energy is not given via this cards. At initialization time, it is read from the OMBEAM cards and passed to the Lepto routines. The option LST(17)=1 (variable beam energy) is switched off (the beam energy is the mean value of the distribution) because the Lepto manual still warns about its usage.

Note that there is no links yet between GEANT target material and the Lepto target material.

AROMA

To be implemented.

Massimo Lamanna