Applying the MINERvA tune

Contact Stephen Dolan or Clarence Wret for more info.

Introduction

The "MINERvA tune" (see for example Xianguo's talk at NuInt18 or Kevin's talk at ECT* 2018) starts with the standard GENIE 2.8.4. MINERvA then add in Nieves 2p2h events from GENIE 2.12.xx, which will need to be added

The three main ingredients of the MINERvA tune is:

• A single pion production tune from Wilkinson et al (arXiv:1601.01888, K. Eur. Phys. J. C (2016) 76: 474). MINERvA explicitly only uses the non-resonant reduction, and does not change MARes or CCResNorm.
• A CCQE modification from the combined effects of a Local Fermi Gas (LFG) and the Relativistic Random Phase Approximation (RPA). MINERvA uses Rik Gran's studies (arXiv:1705.02932, FERMILAB-FN-1030-ND) to modify GENIE.
• A custom Gaussian 2p2h enhancement in q₀ and q₃, tuned to MINERvA CC-inclusive data in reconstructed space and E_available and q₃. See Rik's NuInt 2017 talk and Xianguo's NuInt 2018 talk.

NUISANCE has the ability to turn this tune on for any GENIE events, granted it will only be the "true MINERvA tune" when applied to GENIE 2.8.4.

Please note that MINERvA collaborators have reassured us that generating events with GENIE 2.12.xx and then applying the tune is virtually identical to using the "full recipe".

How to run

Stephen broke down the procedure into

Event generation

• Run GENIE 2.8.4 in default configuration: PLEASE use a uniformly binned flux because early GENIE did not support anything else but does not warn you about it.
• Run GENIE 2.12.10 for Nieves 2p2h only. To achieve this
  • Modify the MEC-CC EventGenerator in ${GENIE}/config/UserPhysicsOptions.xml to use genie::NievesSimoVacasMECPXSec2016/Default and change the DiNucleonCode accordingly.
    i.e. have the lines <param type="alg" name="XSecModel@genie::EventGenerator/MEC-CC"> genie::NievesSimoVacasMECPXSec2016/Default </param> and <param type="bool" name="SetDiNucleonCode"> true </param> present
  • When running gevgen specify --event-generator-list=CCMEC, which turns on generation for CC MEC only

NUISANCE with GENIE 2.12.10

• Build NUISANCE against your GENIE 2.12.10 with -DUSE_MINERvA_RW=1 -DUSE_GENIE=1
• Run NUISANCE with MINERvA 2p2h tune in attached card on GENIE 2.12.10 output

NUISANCE with GENIE 2.8.4

• Build another NUISANCE against 2.8.4 (where 2.8.4 had been bulit w/ GENIE ReWeight libraries) with -DUSE_MINERvA_RW=1 -DUSE_GENIE=1 -DUSE_REWEIGHT=1
• Run NUISANCE with MINERvA RikRPA (QE) parameters in the card (as you specified) on GENIE 2.8.4 output. This will result in an error asking you to download required files for RikRPA: please follow those instructions
• Run NUISANCE with MINERvA RikRPA and NonRESBG GENIE parameters in the attached card on GENIE 2.8.4 output
• Have a beer to celebrate a job well done!

The shorter (and slightly incorrect) version

Clarence is a little lazier and usually just runs GENIE 2.12.xx with Nieves 2p2h on, generating with --event-generator-list=Default+CCMEC. He then builds one instance of NUISANCE against one instance of GENIE 2.12.xx and applies the tune via the cardfile below. This is virtually identical to the full method of using GENIE 2.8.4 and GENIE 2.12.10 separately, but involves less steps.

The card file with the tune

The MINERvA tune is applied as a combination of various custom parameters (e.g. GaussianCorr) and GENIE ReWeight parameters. They can be fed to nuisflat, nuiscomp and nuismin as per usual by specifying the card file by -c cardfile.xml.

Please include the follow lines in any standard NUISANCE card file to turn the tune on: