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GENIE-MC / Generator

The popular GENIE Generator product is used by nearly all accelerator neutrino experiments and it plays a key role in the exploitation of neutrino data. The Generator implements a modern software framework and it includes state-of-the-art physics modules. It captures the latest results of the GENIE global analysis of neutrino scattering data and includes several tunes that were produced using the proprietary Comparisons and Tuning products. The GENIE physics model is universal and comprehensive: It handles all neutrinos and targets, and all processes relevant from MeV to PeV energy scales. The Generator includes several tools (flux drivers, detector geometry navigators, specialized event generation apps, event reweighting engines) to simulate complex experimental setups in full detail and to support generator-related analysis tasks.
http://www.genie-mc.org
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Change configuration for Diffractive event generator #312

Closed idkakorin closed 1 year ago

idkakorin commented 1 year ago

The diffractive scattering this is a process like $\nu\mu + p \rightarrow \mu^- + \pi^+ + p$ and $\bar\nu\mu + p \rightarrow \mu^+ + \pi^- + p$ (see e.g Phys. Rev. D 97 (2018) 032014 or Nucl. Phys. B 278 (1986) 61-77). The typical diffractive event looks like:

|------------------------------------------------------------------------------------------------------------------|
|GENIE GHEP Event Record [print level:   3]                                                                        |
|------------------------------------------------------------------------------------------------------------------|
| Idx |          Name | Ist |        PDG |   Mother  | Daughter  |      Px |      Py |      Pz |       E |      m  | 
|------------------------------------------------------------------------------------------------------------------|
|   0 |         nu_mu |   0 |         14 |  -1 |  -1 |   2 |   2 |   0.000 |   0.000 |   9.274 |   9.274 |   0.000 | 
|   1 |        proton |   0 |       2212 |  -1 |  -1 |   3 |   4 |   0.000 |   0.000 |   0.000 |   0.938 |   0.938 | 
|   2 |           mu- |   1 |         13 |   0 |  -1 |  -1 |  -1 |  -0.180 |  -0.155 |   6.267 |   6.273 |   0.106 | P = (0.029,0.025,-0.999)
|   3 |        proton |   1 |       2212 |   1 |  -1 |  -1 |  -1 |   0.075 |  -0.191 |   0.055 |   0.962 |   0.938 | 
|   4 |           pi+ |   1 |        211 |   1 |  -1 |  -1 |  -1 |   0.104 |   0.346 |   2.953 |   2.978 |   0.140 | 
|------------------------------------------------------------------------------------------------------------------|
|       Fin-Init:                                                |   0.000 |   0.000 |   0.000 |   0.000 |         | 
|------------------------------------------------------------------------------------------------------------------|
|       Vertex:          nu_mu @ (x =     0.00000 m, y =     0.00000 m, z =     0.00000 m, t =    0.000000e+00 s)  |
|------------------------------------------------------------------------------------------------------------------|
| Err flag [bits:15->0] : 0000000000000000    |  1st set:                                                     none | 
| Err mask [bits:15->0] : 1111111111111111    |  Is unphysical:    NO |   Accepted:   YES                          |
|------------------------------------------------------------------------------------------------------------------|
| sig(Ev) =       1.12746e-39 cm^2  | d3sig(x,y,t;E)/dxdydt =   4.35524e-38 cm^2/GeV^2 | Weight =          1.00000 |
|------------------------------------------------------------------------------------------------------------------|

--------------------------------------------------------------------------------------------------------------
GENIE Interaction Summary
--------------------------------------------------------------------------------------------------------------
[-] [Init-State] 
 |--> probe        : PDG-code = 14 (nu_mu)
 |--> nucl. target : Z = 1, A = 1, PDG-Code = 1000010010 (H1)
 |--> hit nucleon  : PDC-Code = 2212 (proton)
 |--> hit quark    : no set
 |--> probe 4P     : (E =     9.274294, Px =     0.000000, Py =     0.000000, Pz =     9.274294)
 |--> target 4P    : (E =     0.938272, Px =     0.000000, Py =     0.000000, Pz =     0.000000)
 |--> nucleon 4P   : (E =     0.938272, Px =     0.000000, Py =     0.000000, Pz =     0.000000)
[-] [Process-Info]  
 |--> Interaction : Weak[CC]
 |--> Scattering  : DFR
[-] [Kinematics]
 |--> *Selected* Bjorken x = 0.015741
 |--> *Selected* Inelasticity y = 0.323659
 |--> *Selected* Momentum transfer Q2 (>0) = 0.088668
 |--> *Selected* Hadronic invariant mass W = 2.534665
 |--> *Selected* COH 4p transfer to nucleus = 0.044689
[-] [Exclusive Process Info] 
 |--> charm prod.  : false |--> strange prod.  : false
 |--> f/s nucleons : N(p) = 1 N(n) = 0
 |--> f/s pions    : N(pi^0) = 0 N(pi^+) = 1 N(pi^-) = 0
 |--> f/s Other    : N(gamma) = 0 N(Rho^0) = 0 N(Rho^+) = 0 N(Rho^-) = 0
 |--> resonance    : [not set]
 |--> final quark prod.  : false
 |--> final lepton prod.  : false
--------------------------------------------------------------------------------------------------------------

Therefore, event generator for diffractive events must not have Fermi Movier, Hadron Transporter. That is, it should be like coherent event generator.

candreop commented 1 year ago

This was a major oversight (that has survived many release validations!) probably resulting from copying and pasting the XML block in EventGenerator.xml. Thanks for catching this!