Meson Exchange Current (MEC) model in Neutrino Interaction Generator

Transcription

1 Meson Exchange Current (MEC) model in Neutrino Interaction Generator outline 1. Introduction 2. Letonic simulation in GENIE 3. Hadronic simulation in GENIE 4. Comarisons 5. Discussion Teei Katori Massachusetts Institute of Technology (and Cordão de Ouro Chicago) NuInt12, CBPF, Rio de Janeiro, Brazil, Oct. 22,

2 1. Introduction 2. Letonic simulation in GENIE 3. hadronic simulation in GENIE 4. Comarisons 5. Discussion 2

3 1. Introduction of Meson Exchange Current (MEC) Benhar, Day, Sick Rev.Mod.Phys80(2008)189 Meson Exchange Current (MEC) in e-scattering - MEC is conceived long time to contribute at di region e-beam Inclusive electron scattering with function of energy loss target e θ detector ω=e(e )-E(e) N 3

4 1. Introduction of Meson Exchange Current (MEC) Benhar, Day, Sick Rev.Mod.Phys80(2008)189 Meson Exchange Current (MEC) in e-scattering - MEC is conceived long time to contribute at di region e-beam Inclusive electron scattering with function of energy loss target e θ detector ω=e(e )-E(e ) N 4

5 1. Introduction of Meson Exchange Current (MEC) Benhar, Day, Sick Rev.Mod.Phys80(2008)189 Meson Exchange Current (MEC) in e-scattering - MEC is conceived long time to contribute at di region e-beam Inclusive electron scattering with function of energy loss target e θ detector ω=e(e )-E(e ) e N A quasi-elastic e N A 5

6 1. Introduction of Meson Exchange Current (MEC) Benhar, Day, Sick Rev.Mod.Phys80(2008)189 Meson Exchange Current (MEC) in e-scattering - MEC is conceived long time to contribute at di region e-beam Inclusive electron scattering with function of energy loss target e θ detector ω=e(e )-E(e ) e N A quasi-elastic e N A Δ-excitation e e Δ π N A A 6

7 1. Introduction of Meson Exchange Current (MEC) Benhar, Day, Sick Rev.Mod.Phys80(2008)189 Meson Exchange Current (MEC) in e-scattering - MEC is conceived long time to contribute at di region e-beam Inclusive electron scattering with function of energy loss target e θ detector ω=e(e )-E(e ) e N A quasi-elastic e N A Δ-excitation e e Δ π N A A e N DIS e X 7

8 1. Introduction of Meson Exchange Current (MEC) Benhar, Day, Sick Rev.Mod.Phys80(2008)189 Meson Exchange Current (MEC) in e-scattering - MEC is conceived long time to contribute at di region e-beam Inclusive electron scattering with function of energy loss target e θ detector ω=e(e )-E(e ) e N A quasi-elastic e N A Δ-excitation e e Δ π N A A di region e N DIS e X 8

9 1. Introduction of Meson Exchange Current (MEC) Benhar, Day, Sick Rev.Mod.Phys80(2008)189 Meson Exchange Current (MEC) in e-scattering - MEC is conceived long time to contribute at di region e-beam Inclusive electron scattering with function of energy loss target e θ detector ω=e(e )-E(e ) e N A quasi-elastic e N A Δ-excitation e e Δ π N A A di region e MEC e A π N 1 N 2 A e N DIS e X 9

10 1. Introduction of Meson Exchange Current (MEC) Van Orden and Donnelly Annals.Phys.131(1981)451 Meson Exchange Current (MEC) in e-scattering - MEC is conceived long time to contribute at di region - MEC also contributes to QE eak (~10%) QE Δ-excitation MEC 10

11 1. Introduction of Meson Exchange Current (MEC) Carlson et al, PRC65(2002) Meson Exchange Current (MEC) in e-scattering - MEC is conceived long time to contribute at di region - MEC also contributes to QE eak (~10%) - MEC may contribute more than we thought Note: Calculation with good NN otential has correlations Light nuclei only Non-relativistic Longitudinal resonse of 4 He Transverse resonse of 4 He 40-50% 11

12 1. Introduction of Meson Exchange Current (MEC) Martini et al, PRC80(2009) Meson Exchange Current (MEC) in e-scattering - MEC is conceived long time to contribute at di region - MEC also contributes to QE eak (~10%) - MEC may contribute more than we thought - This rocess may be needed to describe recent QE ν-xs data ν µ CCQE total xs, RPA+n-nh effect RPA+n-nh RPA 12

13 1. Introduction of Meson Exchange Current (MEC) Nieves et al, Nucl.Phys.A627(1997)543 PRC83(2011) Meson Exchange Current (MEC) in e-scattering - MEC is conceived long time to contribute at di region - MEC also contributes to QE eak (~10%) - MEC may contribute more than we thought - This rocess may be needed to describe recent QE ν-xs data - MEC verified in e-scattering agrees with ν-scattering Note, Local Fermi gas with extra correlations, MEC, ion roduction exclusive e-scattering on 12 C E=620MeV θ=60 o ν µ CCQE total xs on 12 C More about MEC theory, see all talks on Friday 13

14 1. Introduction of Meson Exchange Current (MEC) Meson Exchange Current (MEC) in e-scattering - MEC is conceived long time to contribute in di region - MEC also contributes to QE eak (~10%) - MEC may contribute more than we thought - This rocess may be needed to describe recent QE ν-xs data - MEC verified in e-scattering agrees with ν-scattering Goal of this rogram - Build the model consistent with both e-scattering and ν-scattering exeriments - Imlement such model in MC generator to simulate neutrino exeriments - Predict realistic signal of MEC in neutrino exeriments ν µ n 14

15 1. Introduction 2. Letonic simulation in GENIE 3. hadronic simulation in GENIE 4. Comarisons 5. Discussion 15

16 2. MEC simulation in GENIE Currently, hadronic kinematic distributions are not available from any models in the market ν µ n Therefore imlementation of MEC takes several stes (1) secify letonic model - Choose a model to generate leton differential cross section - Energy-momentum transfer is secified from the model - Verify the model using e-scattering data (2) secify hadronic model - Model how to ick u 2 nucleons - Model how to share the energy-momentum transfer, to knock-out 2 nucleons (3) secify FSI model - Outgoing leton and nucleons undertake standard FSI model in GENIE 16

17 2. MEC simulation in GENIE Currently, hadronic kinematic distributions are not available from any models in the market ν µ n Therefore imlementation of MEC takes several stes (1) secify letonic model - Choose a model to generate leton differential cross section - Energy-momentum transfer is secified from the model - Verify the model using e-scattering data (2) secify hadronic model - Model how to ick u 2 nucleons - Model how to share the energy-momentum transfer, to knock-out 2 nucleons (3) secify FSI model - Outgoing leton and nucleons undertake standard FSI model in GENIE 17

18 2. MEC simulation in GENIE Currently, hadronic kinematic distributions are not available from any models in the market ν µ n Therefore imlementation of MEC takes several stes (1) secify letonic model - Choose a model to generate leton differential cross section - Energy-momentum transfer is secified from the model - Verify the model using e-scattering data (2) secify hadronic model - Model how to ick u 2 nucleons - Model how to share the energy-momentum transfer, to knock-out 2 nucleons (3) secify FSI model - Outgoing leton and nucleons undertake standard FSI model in GENIE 18

19 2. MEC simulation in GENIE Currently, hadronic kinematic distributions are not available from any models in the market ν µ n Therefore imlementation of MEC takes several stes (1) secify letonic model - Choose a model to generate leton differential cross section - Energy-momentum transfer is secified from the model - Verify the model using e-scattering data (2) secify hadronic model - Model how to ick u 2 nucleons - Model how to share the energy-momentum transfer, to knock-out 2 nucleons (3) secify FSI model - Outgoing leton and nucleons undertake standard FSI model in GENIE 19

20 2. Letonic simulation in GENIE In GENIE, Neutrino interaction is simulated in several stes (1) secify letonic model (2) secify hadronic model (3) secify FSI model MEC model requirement - It enhances total neutrino cross section ~30% - It enhances more high angle scattering due to transverse nature - It reroduces inclusive e-scattering data ν µ n 20

21 2. Letonic simulation in GENIE In GENIE, Neutrino interaction is simulated in several stes (1) secify letonic model (2) secify hadronic model (3) secify FSI model Dytman model - First MEC model in GENIE - Based on early work by Lightbody and O Connell - Easy to imlement, easy to tune ν µ n Feature - New MEC channel has only magnetic form factor (Pauli form factor) - MEC channel is Gaussian (mean~ 1.9 GeV width~150 MeV) - Linear A deendence to match revious studies Lightbody model Lightbody and O Connell Com in Phys. May/June(1988)57 QE (Gaussian) Δ (Cauchy) MEC (Cauchy) 21

22 2. Letonic simulation in GENIE In GENIE, Neutrino interaction is simulated in several stes (1) secify letonic model (2) secify hadronic model (3) secify FSI model Dytman model - First MEC model in GENIE - Based on early work by Lightbody and O Connell - Easy to imlement, easy to tune ν µ n Lightbody and O Connell Com in Phys. May/June(1988)57 ν µ - 12 C total cross section CCQE MEC CCQE MEC monotonically turn off (after 1 GeV) 22

23 2. Comarison with e-scattering data In GENIE, Neutrino interaction is simulated in several stes (1) secify letonic model (2) secify hadronic model (3) secify FSI model ν µ n Carbon target, 560MeV, 36 o (Q 2 ~0.1GeV 2 ) At low angle, RFG model overestimate QE eak MEC is small contribution at low angle 23

24 2. Comarison with e-scattering data In GENIE, Neutrino interaction is simulated in several stes (1) secify letonic model (2) secify hadronic model (3) secify FSI model ν µ n Carbon target, 560MeV, 60 o (Q 2 ~0.2GeV 2 ) MEC is related to transverse resonse function More imortant at larger scattering angle Pion roduction model is under develoment 24

25 2. Comarison with e-scattering data In GENIE, Neutrino interaction is simulated in several stes (1) secify letonic model (2) secify hadronic model (3) secify FSI model ν µ n Carbon target, 560MeV, 145 o (Q 2 ~0.5GeV 2 ) MEC is related to transverse resonse function More imortant at larger scattering angle Pion roduction model is under develoment 25

26 2. GENIE rediction for neutrino exeriment ν µ In GENIE, Neutrino interaction is simulated in several stes (1) secify letonic model (2) secify hadronic model (3) secify FSI model Neutrino interaction kinematics - with NuMI low energy configuration - matches MINERvA n - all (no π) - QE - MEC - all (no π) - QE - MEC 26

27 MiniBooNE collaboration, PRD81(2010) Comarison with MiniBooNE data In GENIE, Neutrino interaction is simulated in several stes (1) secify letonic model (2) secify hadronic model (3) secify FSI model Comarison with MiniBooNE flux-folded ν µ CCQE double differential cross section data Tmu distribution, 0.8 < cosθ µ < 0.9 GENIE MiniBooNE data ν µ n Tmu distribution, 0.8 < cosθ µ < Slight over estimation at low angle muons 27

28 MiniBooNE collaboration, PRD81(2010) Comarison with MiniBooNE data In GENIE, Neutrino interaction is simulated in several stes (1) secify letonic model (2) secify hadronic model (3) secify FSI model Comarison with MiniBooNE flux-folded ν µ CCQE double differential cross section data Tmu distribution, 0.8 < cosθ µ < 0.9 GENIE MiniBooNE data ν µ n Decomosition of GENIE rediction - it shows comlicated mix due to flux distribution Channels (no cut) - total - CCQE - MEC - RES - others 28

29 MiniBooNE collaboration, PRD81(2010) Comarison with MiniBooNE data In GENIE, Neutrino interaction is simulated in several stes (1) secify letonic model (2) secify hadronic model (3) secify FSI model Decomosition of Valencia model - theory-based model is somewhat different - MiniBooNE data - Full model - Full QE (with RPA) - Multi-nucleon - No RPA, No Multi-nuc MA=1.049 GeV ν µ n Decomosition of GENIE rediction - it shows comlicated mix due to flux distribution Channels (no cut) - total - CCQE - MEC - RES - others 29

30 MiniBooNE collaboration, PRD81(2010) Comarison with MiniBooNE data In GENIE, Neutrino interaction is simulated in several stes (1) secify letonic model (2) secify hadronic model (3) secify FSI model Comarison with MiniBooNE flux-folded ν µ CCQE double differential cross section data Tmu distribution, 0.5 < cosθ µ < 0.6 ν µ n Tmu distribution, 0.8 < cosθ µ < Slight over estimation at low angle muons GENIE MiniBooNE data Tmu distribution, 0.5 < cosθ µ < MC agrees with data at mild angle 30

31 MiniBooNE collaboration, PRD81(2010) Comarison with MiniBooNE data In GENIE, Neutrino interaction is simulated in several stes (1) secify letonic model (2) secify hadronic model (3) secify FSI model Comarison with MiniBooNE flux-folded ν µ CCQE double differential cross section data Tmu distribution, -0.1 < cosθ µ < 0.0 ν µ n Tmu distribution, 0.8 < cosθ µ < Slight over estimation at low angle muons GENIE MiniBooNE data Tmu distribution, 0.5 < cosθ µ < MC agrees with data at mild angle Tmu distribution, -0.1 < cosθ µ < Slight under estimation at high angle But remember the model is tested with electron data only! 31

32 2. Letonic simulation in GENIE In GENIE, Neutrino interaction is simulated in several stes (1) secify letonic model (2) secify hadronic model (3) secify FSI model Kinematic constraint - Letonic constraint (energy-momentum conservation) - Hadronic constraint (model deendent kinematic constraint) - Both CCQE and MEC show ~2% Hadronic constraint violation ν µ n Ankowski et al, PRD82(2010) ν µ - 12 C 800 MeV CCQE hase sace ν µ - 12 C 800 MeV MEC hase sace Letonic constraint Hadronic constraint 32

33 1. Introduction 2. Letonic simulation in GENIE 3. hadronic simulation in GENIE 4. Comarisons 5. Discussion 33

34 3. Hadron simulation in GENIE In GENIE, Neutrino interaction is simulated in several stes (1) secify letonic model (2) secify hadronic model (3) secify FSI model Kinematic distribution of nucleon need to be modelled. MEC model defines leton kinematics, and Hadron model defines nucleon kinematics. Nucleon cluster model - Simle but reasonable model (GENIE, NuWro) - it has enough flexibility to add more features later ν µ n 34

35 3. Nucleon cluster model in GENIE For a given Energy-Momentum transfer Choose 2 nucleons from secified kinematics (e.g., Fermi gas) Fermi gas - nucleon kinematics are randomly chosen from Fermi sea (GENIE, GiBUU, NuWro) Sectral function - nucleon kinematics can be chosen from sectral function Phase sace density - cross section is weighted with nucleon hase sace density (GiBUU) q 35

36 3. Nucleon cluster model in GENIE For a given Energy-Momentum transfer Choose 2 nucleons from secified kinematics (e.g., Fermi gas) 2. All n-n, n-, - airs are allowed, if interaction is allowed e.g.) ν µ - 12 C CC MEC interaction - It requires at least one neutron (- air is forbidden) - based on random choice, n- : n-n ~ 3 : 1 (NuWro, GiBUU) - based on isosin conjecture, n- : n-n ~ 1 : 4 (GENIE) - based on short range correlation n- : n-n ~ 90 : 5 Some theory also seculate n- >> n-n (Martini model) forbidden q q q n n n 36

37 3. Nucleon cluster model in GENIE For a given Energy-Momentum transfer Choose 2 nucleons from secified kinematics (e.g., Fermi gas) 2. All n-n, n-, - airs are allowed, if interaction is allowed 3. Energy-momentum conservation e.g.) GENIE - 2 nucleons make a on-shell cluster q q n P n nucleon cluster -P recoil nuclei 37

38 3. Nucleon cluster model in GENIE For a given Energy-Momentum transfer Choose 2 nucleons from secified kinematics (e.g., Fermi gas) 2. All n-n, n-, - airs are allowed, if interaction is allowed 3. Energy-momentum conservation e.g.) GENIE - 2 nucleons make a on-shell cluster - Energy-momentum transfer and nucleon cluster makes CM system (hadronic system) q n q 38

39 3. Nucleon cluster model in GENIE For a given Energy-Momentum transfer Choose 2 nucleons from secified kinematics (e.g., Fermi gas) 2. All n-n, n-, - airs are allowed, if interaction is allowed 3. Energy-momentum conservation e.g.) GENIE - 2 nucleons make a on-shell cluster - Energy-momentum transfer and nucleon cluster makes CM system (hadronic system) - Isotroic decay (random θ and φ) of hadronic system creates 2 nucleon emission q n q q θ 39

40 3. Nucleon cluster model in GENIE For a given Energy-Momentum transfer Choose 2 nucleons from secified kinematics (e.g., Fermi gas) 2. All n-n, n-, - airs are allowed, if interaction is allowed 3. Energy-momentum conservation e.g.) GENIE - 2 nucleons make a on-shell cluster - Energy-momentum transfer and nucleon cluster makes CM system (hadronic system) - Isotroic decay (random θ and φ) of hadronic system creates 2 nucleon emission - Boost back to lab frame µ ν q n q q θ 40

41 3. Nucleon cluster model in GENIE For a given Energy-Momentum transfer Choose 2 nucleons from secified kinematics (e.g., Fermi gas) 2. All n-n, n-, - airs are allowed, if interaction is allowed 3. Energy-momentum conservation e.g.) GENIE - 2 nucleons make a on-shell cluster - Energy-momentum transfer and nucleon cluster makes CM system (hadronic system) - Isotroic decay (random θ and φ) of hadronic system creates 2 nucleon emission - Boost back to lab frame µ Issues: - correlations may exist in initial 2 nucleons, any models? - certain airs may be favoured, any models? - searation energy, binding energy, etc, any measurements? The model can be extended to include these feature later ν 41

42 3. Nucleon cluster kinematics Nucleon cluster kinematic distribution - Isotroic momentum distribution - Nucleon cluster has more symmetric momentum distribution than CCQE, extends to higher energy q nucleon cluster n P θ -P recoil nuclei initial nucleon momentum black, CCQE red, CCMEC SRC tail 42

43 3. Nucleon cluster kinematics Nucleon cluster kinematic distribution - Isotroic momentum distribution - Nucleon cluster has more symmetric momentum distribution than CCQE, extends to higher energy - Isotroic angular distribution - Nucleon cluster has no referred direction against momentum transfer -P q nucleon cluster n recoil nuclei P θ initial nucleon momentum oening angle of initial nucleon to momentum transfer black, CCQE red, CCMEC black, CCQE red, CCMEC SRC tail 43

44 3. Nucleon cluster model kinematics for 800 MeV ν µ on 12 C 2 outgoing nucleon kinematics - 2 outgoing nucleons tend to be back-to-back (model deendent feature) θ -P recoil nuclei oening angle of 2 outgoing nucleons (before FSI) red, CCMEC Oening angle of 2 nucleons are naturally large 44

45 3. Nucleon cluster model kinematics for 800 MeV ν µ on 12 C In GENIE, Neutrino interaction is simulated in several stes (1) secify letonic model (2) secify hadronic model (3) secify FSI model leading nucleons θ GENIE FSI model (ha FSI model) - After FSI, MEC still has larger oening angle for 2 nucleons than CCQE -P recoil nuclei oening angle of 2 outgoing nucleons (before FSI) oening angle of 2 leading outgoing nucleons (after FSI) red, CCMEC red, CCMEC 45

46 3. Nucleon cluster model kinematics for 800 MeV ν µ on 12 C In GENIE, Neutrino interaction is simulated in several stes (1) secify letonic model (2) secify hadronic model (3) secify FSI model leading nucleons θ GENIE FSI model (ha FSI model) - After FSI, MEC still has larger oening angle for 2 nucleons than CCQE - This is rare configuration for CCQE and resonance -P recoil nuclei oening angle of 2 outgoing nucleons (before FSI) red, CCMEC oening angle of 2 leading outgoing nucleons (after FSI) black, CCQE red, CCMEC blue, CCRES 46

47 3. Nucleon cluster model kinematics for 800 MeV ν µ on 12 C In GENIE, Neutrino interaction is simulated in several stes (1) secify letonic model (2) secify hadronic model (3) secify FSI model leading nucleons f1 θ GENIE FSI model (ha FSI model) - leading outgoing nucleon momentum - leading outgoing nucleon angle -P recoil nuclei Nucleon cluster model may redict interesting event toologies black, CCQE red, CCMEC blue, CCRES black, CCQE red, CCMEC blue, CCRES 47

48 3. SciBooNE multi-track analysis Alcaraz-Aunion PhD thesis SciBooNE CC analysis - total rate is normalized to CC inclusive measurement - data is comared with NeuT rediction - 3 track data shows excess, this can be exlained by many ways - Resonance channel xs is underestimated? - FSI is not modelled correctly? - Indication of multi-nucleon emission? SciBooNE CC track number marker, data black, CCQE red, CCRES blue, others 48

49 1. Introduction 2. Letonic simulation in GENIE 3. hadronic simulation in GENIE 4. Comarisons 5. Discussion 49

50 4. MEC model in NuWro NuWro - 2 choices of MEC model - n-nh model (based on Marteau model) - TEM (Transverse enhancement model) - Nucleon cluster model similar to GENIE (more attention to energy balance) Sobczyk, PRD86(2012) Martini et al, PRC80(2009) Bodek et al, EUJC71(2011)

51 4. Sum of all nucleon kinetic energy NuWro - 2 choices of MEC model - n-nh model (based on Marteau model) - TEM (Transverse enhancement model) - Nucleon cluster model similar to GENIE (more attention to energy balance) Sobczyk, PRD86(2012) Martini et al, PRC80(2009) Bodek et al, EUJC71(2011)1726 Different redictions on energy transfer rovide different redictions on total kinetic energy, but after FSI, most of structure is gone 51

52 4. Sum of all nucleon kinetic energy Sobczyk, PRD86(2012) NuWro - 2 choices of MEC model - n-nh model (based on Marteau model) - TEM (Transverse enhancement model) - Nucleon cluster model similar to GENIE (more attention to energy balance) For GENIE, Dytman model has Gaussian energy transfer, therefore has symmetric kinetic energy distribution. GENIE ν µ - 12 C 800 MeV total outgoing nucleon kinetic energy CCMEC no FSI CCMEC with FSI 52

53 4. Max nucleon momentum Sobczyk, PRD86(2012) NuWro - 2 choices of MEC model - n-nh model (based on Marteau model) - TEM (Transverse enhancement model) - Nucleon cluster model similar to GENIE (more attention to energy balance) For GENIE, Dytman model has Gaussian energy transfer, therefore has symmetric kinetic energy distribution. GENIE ν µ - 12 C 800 MeV total outgoing nucleon kinetic energy CCMEC no FSI CCMEC with FSI 53

54 4. MEC model in GiBUU Lalakulich et al, PRC86(2012) One-article hase sace density Trile differential cross section (solution of couled Kadanoff-Baym eqn.) - A secial care is aid for the hase sace - 2 nucleons start from same location (effect of nuclear density is squared) Symmetry factor (n-n, - air=1/2, n- air=1) k q 1 (x) k 3 2 (x) 4 (=P- 3 ) 54

55 4. Total cross section, with N-nucleons GiBUU - A secial care is aid for the hase sace - 2 nucleons start from same location) - hadronic tensor is transverse rojector (model II) - FSI controls final state articles Lalakulich et al, PRC86(2012) GiBUU ν µ - 12 C total cross section for multi-nucleon knockout (after FSI) 2-2h doesn t contribute to 1 nucleon knockout - MEC model shouldn t enhance 1-nucleon knock out after FSI: QE Δ 22h k q 1 (x) k 3 2 (x) 4 (=P- 3 ) Eν (GeV)

56 4. Total cross section, with N-nucleons GiBUU - A secial care is aid for the hase sace - 2 nucleons start from same location) - hadronic tensor is transverse rojector (model II) - FSI controls final state articles Lalakulich et al, PRC86(2012) GiBUU ν µ - 12 C total cross section for multi-nucleon knockout (after FSI) 2-2h doesn t contribute to 1 nucleon knockout - MEC model shouldn t enhance 1-nucleon knock out 1 nucleon after FSI: QE Δ 22h GENIE ν µ - 12 C total xs for multi-nucleon knockout (after FSI) after FSI: QE 22h 2 nucleon 3 nucleon 10/22/ Teei 1 Katori, 1.5 MIT 2 Eν (GeV) Eν (GeV)

57 4. Summary GENIE NuWro GiBUU What kind of Letonic model? Dytman model n-nh model and TEM Transverse rojector for hadronic tensor how to choose 2 nucleon momentum? From Fermi sea, indeendently From Fermi sea, indeendently From Fermi sea, indeendently how to choose 2 nucleon location? both are random both are random both are random, but same location Any correlations? no no no, but xs is weighted by hase sace density what kind of airs? n- or n-n? n- : n-n = 1 : 4 n- : n-n = 3 : 1 n- : n-n = 3 : 1 How to share energymomentum transfer by 2 nucleons? nucleon cluster model nucleon cluster model not clear 57

58 1. Introduction 2. Letonic simulation in GENIE 3. hadronic simulation in GENIE 4. Comarisons 5. Discussion 58

59 5. Discussion The effort to imlement MEC model in MC is just started..., with many oen questions - How to choose 2 initial nucleon kinematics? - How to imlement 2 final nucleon FSI? - What kind of airs are referred, n-n, or n-, or -? - Where are 2 nucleons generated? - Do we assume any correlation of initial nucleon? (momentum and location) Some of them may be described in theoretical models, but what is best way to imlement in MC? (can have significant effect on redictions!) e.g.) Short Range Correlations (SRC) - Initial nucleons can be off-shell - from hadron exeriments, n- air is referred - 2 nucleons are close - initial momenta are correlated (back-to-back) We need more inut for a realistic rediction 59

60 5. Discussion GENIE v First tagged version with MEC - Leton kinematic is based on Dytman model, tests are ongoing with e-scattering data - Hadron kinematic is based on GENIE nucleon cluster model - Will be available Mar Acknowledgement - Costas Andreooulos - Steve Dytman - Hugh Gallagher - Ulrich Mosel - Jan Sobczyk Muito obrigado! 60

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