Release 2.11a


E lectro-
N uclear
I nteraction
G enerator by
M onte-Carlo
A pproach

ENIGMA is an Event Generator for Electron-, Photon-, or Pion-induced reactions on Nucleons or Nuclei. Beam energies should be around 0.5 to 1.5 GeV for electrons, up to ~0.5 GeV for photons or pions.

ENIGMA may generate a number of 2-D histogrammed scatterplots in a subdirectory called results/, or it may generate event-by-event data in ASCII on the standard output, or both.

A translator to ntuple format compatible with PAW and GEANT exists (mc2ntp by Henk den Bok, see: man mc2ntp, after installing Enigma).

ENIGMA can generate events for the following nuclear reactions: 

Reaction           Mnemnonic    Comments
--------           ---------    --------
A(gamma,p pi-)A-1  gamppi-      pion photoproduction
A(gamma,p pi0)A-1  gamppi0      idem 
A(gamma,n pi0)A-1  gamnpi0      idem 
A(gamma,n pi+)A-1  gamnpi+      idem 
A(gamma,p n)A-2    gampn        [Quasi-]deuteron photo dissociation
A(gamma,alpha)A-4  gamalpha     photon-induced alpha knockout
A(gamma,2-alpha)A-8  gamalpha   photon-induced 2-alpha knockout
A(gamma,3-alpha)A-12 gamalpha   photon-induced 3-alpha knockout

A(e,e'p)A-1        eep          Quasi-Free  proton knockout
A(e.e'n)A-1        een          Quasi-Free  neutron knockout
A(e,e'pn)A-2       eepn         [Quasi] 2H  electro-desintegration
A(e,e'pnn)A-3      eepnn        [Quasi] 3H  e-desintegration
A(e,e'ppn)A-3      eeppn        [Quasi] 3He e-desintegration
A(e,e'ppnn)A-4     eeppnn       [Quasi] 4He e-desintegration
d(e,e'pn)          deepn        (Arenhoevels 2H-formalism) (in preparation)

A(e,e'p pi-)A-1    eeppi-       Quasi Free pion electro production
A(e,e'p pi0)A-1    eeppi0       idem 
A(e,e'n pi0)A-1    eenpi0       idem
A(e,e'n pi+)A-1    eenpi+       idem
A(e,e'pi+)A(Z-1)   eepi+        coherent pi+ production
A(e,e'pi0)A        eepi0        coherent pi0 production
A(e,e'pi-)A(Z+1)   eepi-        coherent pi- production

A(pi+,pp)A-2       pi+pp        [Quasi-]2H absorption
A(pi+,pd)A-3       pi+pd        [Quasi-]3H absorption
A(pi+,ppn)A-3      pi+ppn       idem
A(pi+,dd)A-4       pi+dd        [Quasi-]4H absorption
A(pi+,ppp)A-3      pi+ppp       [Quasi-]3He absorption
A(pi+,ppd)A-4      pi+ppd       [Quasi-]4He absorption
A(pi+,pppn)A-4     pi+pppn      idem
A(pi+,pppnn)A-5    pi+pppnn     [Quasi-]5He absorption
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JV / 6 Jan 1994