Interaction modes in NUISANCE

Being originally written for NEUT comparisons, NUISANCE uses the same interaction mode enumeration as NEUT. We primarily use the available converters (e.g. GENIE's genie::utils::ghep::NeutReactionCode(const GHepRecord *event)), with small modifications to account for changes not implemented in the generators.

Access to the underlying GENIE, NuWro, GiBUU or NEUT event is always possible with the pointers being defined in nuisance/src/InputHandler/BaseFitEvt.h (e.g. here for the GENIE GHepRecord).

Important note: remember that some interaction modes do not translate well between generators. This is true for e.g. single-π production→multi-π production→DIS production, which is often defined in terms of pion multiplicity and hadronic mass (W). One generator might call an event with multiple pions at W = 1.9 GeV a multi-π event wheras another would call it a DIS event. Multi-π and DIS events have different interaction codes (21 and 26), so might show large differences between generators. In these cases it might be better to compare the sum of the Multi-π and DIS in some range of W.

Enumeration

The enumeration is taken straight out of NEUT: neut/src/neutcore/nemodsel.F.

Neutrinos have Mode>0 and anti-neutrinos have Mode<0 with the same enumeration (e.g. Mode=-1 for anti-neutrino CCQE). Charged current has Mode<30 and neutral current has Mode>30.

******* CHARGED CURRENT ******* -- ELASTIC -- 1 : NEU,N --> LEPTON-,P 2 : NEU,N+X --> LEPTON-,P+X (X=(N or P)) -- SINGLE PI FROM DELTA RESONANCE -- 11 : NEU,P --> LEPTON-,P,PI+ 12 : NEU,N --> LEPTON-,P,PI0 13 : NEU,N --> LEPTON-,N,PI+ 15 : NEU,P --> LEPTON-,P,PI+ ( diffractive ) 16 : NEU,A --> LEPTON-,A,PI+ -- SINGLE GAMMA FROM DELTA RESONANCE -- 17 : NEU,N --> LEPTON-,P,GAMMA -- SINGLE K : Strangeness violated mode -- (added 14/12/25 Y. Hayato) 18 : NEU,N --> LEPTON-,N,K+ 19 : NEU,N --> LEPTON-,P,K0 20 : NEU,N --> LEPTON-,P,K+ -- MULTI PI (1.3 < W < 2.0 GeV) -- 21 : NEU,(N OR P) --> LEPTON-,(N OR P),MULTI PI -- SINGLE ETA FROM DELTA RESONANCE -- (added 97/12/01 J.Kameda) 22 : NEU,N --> LEPTON-,P,ETA0 -- SINGLE K FROM DELTA RESONANCE -- (added 98/02/25 J.Kameda) 23 : NEU,N --> LEPTON-,LAMBDA,K+ -- DEEP INELASTIC (2.0 GeV < W , JET set) -- 26 : NEU,(N OR P) --> LEPTON-,(N OR P),MESONS ******* NEUTAL CURRENT ******* -- SINGLE PI FROM DELTA RESONANCE -- 31 : NEU,N --> NEU,N,PI0 32 : NEU,P --> NEU,P,PI0 33 : NEU,N --> NEU,P,PI- 34 : NEU,P --> NEU,N,PI+ 15 : NEU,P --> LEPTON-,P,PI0 ( diffractive ) 36 : NEU,A --> NEU,A,PI0 -- SINGLE GAMMA FROM DELTA RESONANCE -- 38 : NEU,N --> NEU,N,GAMMA 39 : NEU,P --> NEU,P,GAMMA -- MULTI PI (1.3 GeV < W < 2.0 GeV) -- 41 : NEU,(N OR P) --> NEU,(N OR P),MULTI PI -- SINGLE ETA FROM DELTA RESONANCE -- (added 97/12/01 J.Kameda) 42 : NEU,N --> NEU,N,ETA0 43 : NEU,P --> NEU,P,ETA0 -- SINGLE K FROM DELTA RESONANCE -- (added 98/02/20 J.Kameda) 44 : NEU,N --> NEU,LAMBDA,K0 45 : NEU,P --> NEU,LAMBDA,K+ -- DEEP INELASTIC (2.0 GeV < W , JET set) -- 46 : NEU,(N OR P) --> NEU,(N OR P),MESONS -- ELASTIC -- 51 : NEU,P --> NEU,P 52 : NEU,N --> NEU,N