Aaron HigueraUniversity of Houston

Kaons in GENIE & in GEANT4

2

Nucleon Decay (p→K + v): Establish understanding of FSI uncertainties and impact on sensitivity

Towards TDR

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FSI hA vs hN

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 KE (GeV)+K

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1800primaryfinal state

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 KE (GeV)+K

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primaryfinal state

hA

hN

Why there are more kaons with lower kinetic energy values in hA than in hN?

Each FSI models simulates the hadron interaction differently

hA uses inelastic scattering only whereas hN uses elastic scattering

(in a inelastic process the KE is degraded)

Do GENIE assumptions match data?

4

FSI hALooking into the code inside GENIE it seems that something is odd

Intranuclear rescattering Use the HadronTransportEnable option to toggle intranuclear rescattering on/off. Also, set the preferred hadron transport model. Options include: - genie::HAIntranuke/Default - genie::HNIntranuke/Default - genie::HAIntranuke2014/Default new 2d spline for piA - genie::HNIntranuke2014/Default - genie::HAIntranuke2015/Default - genie::HNIntranuke2015/Default - genie::HNIntranuke2015/OsetOff --> <param type="bool" name="HadronTransp-Enable"> true </param> <param type="alg" name="HadronTransp-Model"> genie::HAIntranuke/Default </param>

Any hA version calls “HadronData” which points to a data file called tot_xsec/intranuke-fractions-KA.dat A table with values for each cross section as a fraction

# this file has info based on K+A reactions in carbon # data is limited to Friedman (reac and total) and Bugg (total). # KE KA tot KA elas KA inel KA abs 1. 1.0 .5 .1 .4 100. 1.0 .4 .2 .4 400. 1.0 .2 .4 .4 2000. 1.0 .1 .4 .5

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FSI hA

0 200 400 600 800 100012001400160018002000Kaon Kinetic Energy (MeV)

00.20.40.60.8

11.21.41.61.8

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Frac

tion

TotalElasticInelastic

0 500 1000 1500 2000 2500Kaon Kinetic Energy (MeV)

120

140

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Cro

ss s

ectio

n (m

b)

Kaon + Carbon

Bugg et al. Phys. Rev. 168, 1466Friedman et al Phys. Rev. C 55, 1304

TotalInelastic (Friedman)

GENIE

Lets take 400 MeV as example GENIE predicts that 40% of the total cross section is inelasticData, total cross section = 175 (mb), inelastic 142 (mb)

What is going on?

We need to ask a GENIE expert to understand better

6

GEANT4During the simulation process after the generation stage is done GENIE passes a list of particles (FSI particles) into GEANT4 to simulate the pass through matter

GEANT4 will calculate its energy loss (dE/dx), it would calculate the cross section and decide whether it goes under elastic, inelastic or charge exchange interaction

GEANT4 uses a parametrization that was developed using extensive data samples and contains a number of parameters which depend on the particle

How is GEANT4 handling kaons?

Courtesy of Hans Wenzel

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GEANT4Prior to version G4.10.3 patch-03 GEANT4 was not in a good agreement with PDG data

This has been fixed (see version release note)

o Physics Lists: ------------- + constructors/hadron_elastic: o G4HadronElasticPhysics, G4HadronHElasticPhysics: changed kaon elastic cross-sections from, respectively, Gheisha and Chips, to Glauber Gribov ones. This way, the total (elastic + inelastic) kaon cross sections are consistent with the PDG ones.

o Processes - Hadronic: -------------------- + cross_sections: o Bug fix in G4ComponentGGHadronNucleusXsc to use the correct cross- sections for kaons on Hydrogen; use Starkov parameterization for them. + models/cascade:

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GEANT4

210 310 410 510Kaon Kinetic Energy (MeV)

10C

ross

Sec

tion

kaon+P total cross section 4.10.3.p03 FTFP_BERT

w/bug

bug fixed

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GEANT4

200 400 600 800 1000120014001600180020002200Kinetic Energy (MeV)

0

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cros

s se

ctio

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b]

K+ on C total cross section 4.10.3.p03 FTFP_BERTK+ on C elastic cross section 4.10.3.p03 FTFP_BERTK+ on C inelastic cross section 4.10.3.p03 FTFP_BERTBuggFriedman

K+ on C total cross section 4.10.3.p03 FTFP_BERTK+ on C elastic cross section 4.10.3.p03 FTFP_BERTK+ on C inelastic cross section 4.10.3.p03 FTFP_BERTBuggFriedman

K+ on C total cross section 4.10.3.p03 FTFP_BERT

100 200 300 400 500 600 700 800Kaon Kinetic Energy (MeV)

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ectio

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kaon+ p total cross section 4.10.3.p03 FTFP_BERT

Carbon

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GEANT4

100 200 300 400 500 600 700 800Kaon Kinetic Energy (MeV)

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ectio

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kaon+ p total cross section 4.10.3.p03 FTFP_BERT

200 400 600 800 1000120014001600180020002200Kaon Kinetic (MeV)

0100200300400500600700800900

1000

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s se

ctio

n [m

b]

K+ on Ar total cross section 4.10.3.p03 FTFP_BERT

K+ on Ar elastic cross section 4.10.3.p03 FTFP_BERT

K+ on Ar inelastic cross section 4.10.3.p03 FTFP_BERT

K+ on Ar total cross section 4.10.3.p03 FTFP_BERT

K+ on Ar elastic cross section 4.10.3.p03 FTFP_BERT

K+ on Ar inelastic cross section 4.10.3.p03 FTFP_BERT

K+ on Ar total cross section 4.10.3.p03 FTFP_BERT

Argon

A2/3 scaling

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Comments

Information about GENIE and kaons is behind the code, there are some parts where it seems that there is something odd with the code

A Q&A session with a GENIE expert would be very useful to understand what is behind the code

Current version of GEANT4 in DUNE software has a known bug for kaon scattering

Need to ask LArSoft team to update GEANT4 version to 4.10.3.p03 or later

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The End

13

Final State Interactions in GENIE Intranuke

(nuclear cascade)

hA hN

INCascade is fully modeled there is a small probability of knowing out every nucleon in an event!!

✤ INC-like w/one effective interactions

✤ Choose interaction from (data hadron+Nucleus or models)

✤ Choose kinematics✤ Exit

✦Full INC✦Choose interaction from data

hadron+Nucleon or models✦Choose kinematicsAdd particles to stack until all out

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FSI hA

INukeFateHA_t HAIntranuke::HadronFateHA(const GHepParticle * p) const { // Select a hadron fate in HA mode

// handle kaons else if (pdgc==kPdgKP || pdgc==kPdgKM) { double frac_inel = fHadroData->Frac(pdgc, kIHAFtInelas, ke); double frac_abs = fHadroData->Frac(pdgc, kIHAFtAbs, ke); LOG("HAIntranuke", pDEBUG) << "\n frac{" << INukeHadroFates::AsString(kIHAFtInelas) << "} = " << frac_inel << "\n frac{" << INukeHadroFates::AsString(kIHAFtAbs) << "} = " << frac_abs; // compute total fraction (can be <1 if fates have been switched off) double tf = frac_inel + frac_abs; double r = tf * rnd->RndFsi().Rndm(); #ifdef __GENIE_LOW_LEVEL_MESG_ENABLED__ LOG("HAIntranuke", pDEBUG) << "r = " << r << " (max = " << tf << ")"; #endif double cf=0; // current fraction if(r < (cf += frac_inel )) return kIHAFtInelas; // inelas if(r < (cf += frac_abs )) return kIHAFtAbs; // abs }

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The End

Rasheed Auguste

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FSI hA & Neutrino Data

There is a recent measurement of kaon production by neutrinos by MINERvA collaboration PRD 94, 012002 (2016)

Data agree best with GENIE w/FSI (chi2 8.11 w/FSI, 11.2 w/o FSI and 27.0 NuWro)MINERvA uses hA for its analysis