Closed jtenavidal closed 9 months ago
The default parameterization for neutrinos is using the "MiniBooNE prenscription": https://arxiv.org/pdf/0909.3659.pdf
For electrons, we are for now using the Dipole prenscription.
I had a look at this paper: https://journals.aps.org/prd/pdf/10.1103/PhysRevD.77.053001 They suggest that the Rarita-Schwinger formalism for V+A form factors has better agreement with electron and neutrino data.
This prenscription is very similar to the current implementation for MiniBooNE. In fact, they should be exact, but they are not. (I believe the arxive had some errors..) The Rarita-Schwinger provides with specific form for EM or CC/NC, but this differentiation was not implemented. In addition, there's two results for the Axial part (Type I and Type II). Both are available on this new version.
Status: I am currently running splines for all cases to evaluate the impact on the electron side, and neutrino side.
This file contains comparisons of EMRES predictions with data (no res-background or DIS is considered). It shows the predictions for 3 different form factor models: Rarita-Schwinger (R-W), Dipole, and the standard GENIE default ( referred to as MiniBooNE form factor in the code) comparisonRES.pdf
The MiniBooNE Form Factor was meant to be the same as Rarita-Schwinger , but the implementation was not correct. The R-S model is a correction of the previous model.
For now the changes do not affect the existing configurations in GENIE, as the MiniBooNE form factor is used. There's additional configurations that the user can use if desired.
For neutrinos, the changes are significant and including them would require a re-tune of the configuration: GVGANeutrinoParameterizations.pdf
The default GENIE for neutrinos is based on "miniBooNE approach". This approach was incorrect for electrons. The correct method for electrons is added - it is called Sarita-Schwinger. The dipole is also an option. The best agreement to data is shown by Sarita-Schwinger. DefaultMBFF.pdf DipoleFF.pdf SRFF.pdf