BDM Resonant Scattering

[ZWorr]

Added Resonant scattering to the Boosted Dark Matter physics module. Modified the framework to include Boosted Dark Matter Resonant Scattering.

[nusense]

This wasn't a review of the physics but of the general code, especially changes to existing code.

[nusense]

Before any merge the previous paragraph about being a fork should be removed.

[nusense]

Actually a big block of stuff here is a reversion of some more recent changes and care must be taken in what's merged in.

[nusense]

Is there a reason that "RES-DM" is not clustered with "RES-DMv1" and "RES-DMv2" up near line 117. Or perhaps those should be down here. Or they're vestigial and need to be removed?

[nusense]

Should an entry for msgstream "DMRes" be added (at different levels) to all the other `Messenger_XYZZY.xml" files?

[nusense]

This addition of mcj_driver->ForceInteraction() doesn't seem DM related and would change the behavior of this application. Is it something that really should be done, or is it leftover from some testing?

[nusense]

You might want to clear up a bunch of empty lines here and right below the next block of code.

[ZWorr]

Robert Hatcher, Thank you for reviewing our pull request of the boosted dark matter resonant scattering process. We have updated the pull request after reviewing your comments. The only unresolved issue might be to block out a range of enum values for dark matter in the src/Framework/Interactions/ScatteringType.h file. As for the occurrence of "special values" in several of the src/Physics/BoostedDarkMatter/EventGen/DMRESKinematicsGenerator.cxx file, these are copied from the src/Physics/Resonance/EventGen/RESKinematicsGenerator.cxx version of the file. Thank you for your help identifying all the other discrepancies. Hopefully our updates have fixed everything. Let me know if there is anything else I missed or other concerns you want me to address. We appreciate your help. Best, Zachary Orr

________________________________ From: Robert Hatcher ***@***.***> Sent: Wednesday, January 14, 2026 3:02 PM To: GENIE-MC/Generator ***@***.***> Cc: Orr,Zach ***@***.***>; Author ***@***.***> Subject: Re: [GENIE-MC/Generator] BDM Resonant Scattering (PR #471) ** Caution: EXTERNAL Sender ** @nusense commented on this pull request. This wasn't a review of the physics but of the general code, especially changes to existing code.

________________________________ In README.md<#471 (comment)>:

@@ -1,5 +1,9 @@

# The GENIE Event Generator +This code is a fork of the GENIE Generator product. For the official release of the GENIE code, please visit +http://www.genie-mc.org for more information. This fork adds the capability to simulate boosted dark matter +scattering via resonant baryon production. It is intended for future merger into an official GENIE release. + The GENIE Generator product is an advanced physics simulation used by nearly all modern neutrino experiments and Before any merge the previous paragraph about being a fork should be removed.

________________________________ In config/EventGenerator.xml<#471 (comment)>:

+ <param_set name="RES-DM">

+ <param type="string" name="VldContext"> </param> + <param type="int" name="NModules"> 10 </param> + <param type="alg" name="Module-0"> genie::InitialStateAppender/Default </param> + <param type="alg" name="Module-1"> genie::VertexGenerator/Default </param> + <param type="alg" name="Module-2"> genie::FermiMover/Default </param> + <param type="alg" name="Module-3"> genie::DMRESKinematicsGenerator/RES </param> + <param type="alg" name="Module-4"> genie::DMRESOutgoingDarkGenerator/Default </param> + <param type="alg" name="Module-5"> genie::DMRESHadronicSystemGenerator/Default </param> + <param type="alg" name="Module-6"> genie::NucDeExcitationSim/Default </param> + <param type="alg" name="Module-7"> genie::HadronTransporter/Default </param> + <param type="alg" name="Module-8"> genie::NucBindEnergyAggregator/Default </param> + <param type="alg" name="Module-9"> genie::UnstableParticleDecayer/AfterHadronTransport </param> + <param type="alg" name="ILstGen"> genie::DMRESInteractionListGenerator/DM-Default </param> + </param_set> + Is there a reason that "RES-DM" is not clustered with "RES-DMv1" and "RES-DMv2" up near line 117. Or perhaps those should be down here. Or they're vestigial and need to be removed?

________________________________ In config/EventGeneratorListAssembler.xml<#471 (comment)>:

</param_set>

<param_set name="DARKNEUTRINO"> <param type="int" name="NGenerators"> 1 </param> <param type="alg" name="Generator-0"> genie::EventGenerator/COHDNu </param> </param_set> + <param_set name="NonRes"> + <param type="int" name="NGenerators"> 3 </param> + <param type="alg" name="Generator-0"> genie::EventGenerator/DMEL </param> + <param type="alg" name="Generator-1"> genie::EventGenerator/DMDIS </param> + <param type="alg" name="Generator-2"> genie::EventGenerator/DME </param> + </param_set> Should the name of this param set include "DM" rather than just be "NonRes"

________________________________ In config/Messenger.xml<#471 (comment)>:

@@ -86,6 +86,7 @@

<priority msgstream="DMELEvent"> NOTICE </priority> <priority msgstream="DMELKinematics"> WARN </priority> <priority msgstream="DMELXSec"> NOTICE </priority> + <priority msgstream="DMRes"> INFO </priority> <priority msgstream="EventGenerator"> WARN </priority> Should an entry for msgstream "DMRes" be added (at different levels) to all the other `Messenger_XYZZY.xml" files?

________________________________ In src/Apps/gAtmoEvGen.cxx<#471 (comment)>:

@@ -368,6 +368,7 @@ int main(int argc, char** argv)

mcj_driver->SetEventGeneratorList(RunOpt::Instance()->EventGeneratorList()); mcj_driver->UseFluxDriver(flux_driver); mcj_driver->UseGeomAnalyzer(geom_driver); + mcj_driver->ForceInteraction(); mcj_driver->Configure(); This addition of mcj_driver->ForceInteraction() doesn't seem DM related and would change the behavior of this application. Is it something that really should be done, or is it leftover from some testing?

________________________________ In src/Framework/EventGen/GMCJDriver.cxx<#471 (comment)>:

@@ -654,11 +654,12 @@ void GMCJDriver::BootstrapXSecSplineSummation(void)

// knots with zero y values (although the GENIE Spline object handles it) double min = rE.min; double max = TMath::Min(rE.max, fEmax); - + max = 1.1 * max; + giving max a 1.1 fudge factor in a universally used class seems to be something that should get wider discussion than this pull request.

________________________________ In src/Framework/Interaction/KPhaseSpace.cxx<#471 (comment)>:

@@ -453,7 +456,7 @@ Range1D_t KPhaseSpace::WLim(void) const

bool is_em = pi.IsEM(); bool is_qel = pi.IsQuasiElastic() || pi.IsInverseBetaDecay() || pi.IsDarkMatterElastic(); bool is_inel = pi.IsDeepInelastic() || pi.IsResonant() || pi.IsDiffractive(); - bool is_dmdis = pi.IsDarkMatterDeepInelastic(); + bool is_dmdis = pi.IsDarkMatterDeepInelastic() || pi.IsDarkMatterResonant(); Here and several places below the is_dmdis seems misleading if it's really DMDIST and DMRES.

________________________________ In src/Framework/Interaction/ScatteringType.h<#471 (comment)>:

@@ -56,6 +56,7 @@ typedef enum EScatteringType {

kScDarkMatterElastic = 101, kScDarkMatterDeepInelastic, kScDarkMatterElectron, + kScDarkMatterResonant, kScNorm I'm always very hesitant about adding enum entries in the middle. This invalidates anything that has stored kScNorm to now look like it is kScDarkMatterResonant. There probably currently isn't anything, but perhaps we should block out a range for dark matter and restart counting with kScNorm=110 or something.

________________________________ In src/Physics/BoostedDarkMatter/EventGen/DMRESKinematicsGenerator.cxx<#471 (comment)>:

+ double max_xsec = 0.;

+ + const InitialState & init_state = interaction -> InitState(); + double E = init_state.ProbeE(kRfHitNucRest); + +//___________For DM cross check with EM________________________________________ +// Q2Thres will be set to 1E-4 +//______________________________________________________________________________ +//Original: +bool is_em = interaction->ProcInfo().IsEM(); +double Q2Thres = is_em ? utils::kinematics::electromagnetic::kMinQ2Limit : controls::kMinQ2Limit; +//______________________________________________________________________________ + + double md; + if(!interaction->ExclTag().KnownResonance()) md=1.23; + else { What is md and why is there a special value of 1.23 in some cases? Maybe at least a comment here.

________________________________ In src/Physics/BoostedDarkMatter/EventGen/DMRESKinematicsGenerator.cxx<#471 (comment)>:

+

+ Wmin = TMath::Max(Wmin, md-.3); + Wmax = TMath::Min(Wmax, md+.3); + + if(Wmax-Wmin<0.05) { NW=1; Wmin=Wmax; } + + double dW = (NW>1) ? (Wmax-Wmin)/(NW-1) : 0.; + + for(int iw=0; iw<NW; iw++) + { + double W = Wmin + iw*dW; + interaction->KinePtr()->SetW(W); + + int NQ2 = 25; + int NQ2b = 4; + I never like seeing "special values" (here 25, 4 and 5, 3 below) without some comment explaining them.

________________________________ In src/Physics/BoostedDarkMatter/XSection/DMRESPXSec.cxx<#471 (comment)>:

+ if (mZprime2 != 0.0){

+ AZ = -mchiTerm*mZ_q2*fQchiLmR2; + } + + //For Scalar DM: spin average = 1 + if(fVelMode == 2){ + AL = fQchiS2 * (2*UV + 2*mchiTerm); + AR = fQchiS2 * (2*UV + 2*mchiTerm); + AS = fQchiS2 * (TMath::Power((U+V), 2)); + AZ = 0.0; +} + + + + + You might want to clear up a bunch of empty lines here and right below the next block of code.

________________________________ In src/Physics/BoostedDarkMatter/XSection/DMRESPXSec.cxx<#471 (comment)>:

+ const XclsTag & xcls = interaction->ExclTag();

+ + if(!proc_info.IsDarkMatterResonant()) return false; + if(!xcls.KnownResonance()) return false; + + int hitnuc = init_state.Tgt().HitNucPdg(); + bool is_pn = (pdg::IsProton(hitnuc) || pdg::IsNeutron(hitnuc)); + + if (!is_pn) return false; + + int probe = init_state.ProbePdg(); + bool is_DM = proc_info.IsDarkMatterResonant(); + bool is_dm = proc_info.IsDarkMatter(); + + if (!is_dm && !is_DM) return false; + I'm not a fan of two variables only differentiated by case. Perhaps using is_dmres might be warranted.

________________________________ In src/Physics/BoostedDarkMatter/XSection/DMRESXSecFast.cxx<#471 (comment)>:

@@ -0,0 +1,223 @@

+//____________________________________________________________________________ +/* + Copyright (c) 2003-2023, The GENIE Collaboration + For the full text of the license visit http://copyright.genie-mc.org + + Igor Kakorin ***@***.***> + Joint Institute for Nuclear Research + Is this Igor Kakorin's code or Zachary Orr's? Also check the copyright ranges ... should probably be up to 2026.

________________________________ In src/Physics/BoostedDarkMatter/XSection/RSHelicityAmplModelDMn.cxx<#471 (comment)>:

+ fAmpl.fMinus1 = k1_Sqrt6 * fkrdm.Lamda * (fkrdm.Ra * (fQuA + 5 * fQdA) - fkrdm.Rv * (fQuV + 5 * fQdV)) + kSqrt3 * fkrdm.Ta * (fQdA - fQuA) + kSqrt3 * fkrdm.Tv * (fQuV - fQdV);

+ fAmpl.fPlus1 = -k1_Sqrt6 * fkrdm.Lamda * (fkrdm.Ra * (fQuA + 5 * fQdA) + fkrdm.Rv * (fQuV + 5 * fQdV)) + kSqrt3 * fkrdm.Ta * (fQuA - fQdA) + kSqrt3 * fkrdm.Tv * (fQuV - fQdV); + fAmpl.fPlus3 = 0; + fAmpl.f0Plus = k1_Sqrt6 * (3 * fkrdm.Lamda * fkrdm.S * (fQdV - fQuV) - 3 * fkrdm.Bs * (fQuA + 5 * fQdA) + fkrdm.Lamda * fkrdm.Cs * (fQuA + 5 * fQdA)); + fAmpl.f0Minus = k1_Sqrt6 * (3 * fkrdm.Lamda * fkrdm.S * (fQuV - fQdV) - 3 * fkrdm.Bs * (fQuA + 5 * fQdA) + fkrdm.Lamda * fkrdm.Cs * (fQuA + 5 * fQdA)); + fAmpl.fz0Plus = -k1_Sqrt6 * ((fQuA + 5 * fQdA) * (3 * fkrdm.Bz - fkrdm.Lamda * fkrdm.Cz)); + fAmpl.fz0Minus = -k1_Sqrt6 * ((fQuA + 5 * fQdA) * (3 * fkrdm.Bz - fkrdm.Lamda * fkrdm.Cz)); + + break; + } + case (kD13_1520) : + { + fAmpl.fMinus3 = k3_Sqrt2 * (fkrdm.Tv * (fQuV - fQdV) + fkrdm.Ta * (fQdA - fQuA)); + fAmpl.fMinus1 = (1/2) * k1_Sqrt3 * (2 * fkrdm.Lamda * (fkrdm.Rv * (5 * fQdV + fQuV) - fkrdm.Ra * (5 * fQdA + fQuA)) + 3 * kSqrt2 * (fkrdm.Tv * (fQuV - fQdV) + fkrdm.Ta * (fQdA - fQuA))); + fAmpl.fPlus1 = (1/2) * k1_Sqrt3 * (-2 * fkrdm.Lamda * (fkrdm.Ra * fQuA + fkrdm.Rv * (5 * fQdV + fQuV)) + fQdA * (3 * kSqrt2 * fkrdm.Ta - 10 * fkrdm.Lamda * fkrdm.Ra) + 3 * kSqrt2 * fkrdm.Tv * (fQdV - fQuV) - 3 * kSqrt2 * fQuA * fkrdm.Ta); + fAmpl.fPlus3 = k3_Sqrt2 * (fkrdm.Tv * (fQdV - fQuV) + fkrdm.Ta * (fQdA - fQuA)); In C++ (1/2) is done as integer math and will always yield zero. You need to make at least one of the two a floating point type.

________________________________ In src/Physics/BoostedDarkMatter/XSection/RSHelicityAmplModelDMn.cxx<#471 (comment)>:

+ fAmpl.fPlus3 = -k3_Sqrt2 * (fkrdm.Tv * (fQdV - fQuV) + fkrdm.Ta * (fQdA - fQuA));

+ fAmpl.f0Plus = fkrdm.Lamda * k1_Sqrt3 * (3 * fkrdm.S * (fQdV - fQuV) + fkrdm.Cs * (fQuA - fQdA)); + fAmpl.f0Minus = fkrdm.Lamda * k1_Sqrt3 * (3 * fkrdm.S * (fQdV - fQuV) + fkrdm.Cs * (fQdA - fQuA)); + fAmpl.fz0Plus = fkrdm.Lamda * fkrdm.Cz * k1_Sqrt3 * (fQuA - fQdA); + fAmpl.fz0Minus = fkrdm.Lamda * fkrdm.Cz * k1_Sqrt3 * (fQdA - fQuA); + + break; + } + case (kP11_1440) : + { + double L2 = TMath::Power(fkrdm.Lamda, 2); + + fAmpl.fMinus3 = 0; + fAmpl.fMinus1 = (1/2) * k1_Sqrt3 * L2 * (fkrdm.Ra * (fQuA - 4 * fQdA) - fkrdm.Rv * (fQuV - 4 * fQdV)); + fAmpl.fPlus1 = (1/2) * k1_Sqrt3 * L2 * (fkrdm.Ra * (fQuA - 4 * fQdA) + fkrdm.Rv * (fQuV - 4 * fQdV)); + fAmpl.fPlus3 = 0; Again (1/2) is 0. Last mention... You'll need to check everywhere (not just this file and these two instances) for this. — Reply to this email directly, view it on GitHub<#471 (review)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/BER2E3MCHR7IWMMKCGHDHOT4G24GFAVCNFSM6AAAAACRW4M2SWVHI2DSMVQWIX3LMV43YUDVNRWFEZLROVSXG5CSMV3GSZLXHMZTMNRSG4YTENRZGU>. You are receiving this because you authored the thread.Message ID: ***@***.***>