Mie scattering has no effect on Cherenkov photons produced by muon propagation

Physics Processes, Models and Cross Sections
1

Geant4 Version: 11.3.2
Operating System: Ubuntu 24.04.4 LTS
Compiler/Version: GCC 13.3.0
CMake Version: 3.28.3

Hello!

I am studying the effect of light scattering on event reconstruction accuracy for the Baikal-GVD neutrino telescope. In my simulation, I compare the number of optical photons reaching the photocathode as a function of the distance between the photon emission point in water and the optical module.

When I test Mie scattering during the direct generation of optical photons, everything works correctly, and the results match my expectations. However, when I simulate muon propagation and detect photons from the resulting Cherenkov cone — the scattering effect disappears. The results are identical whether scattering is enabled or disabled. I have also checked the optical-photon tracking output and verified that the Mie scattering process is actually invoked for the Cherenkov photons.

Could there be any difference in how Mie scattering should be configured or handled for Cherenkov photons produced during muon propagation?

Or could there be another reason why the scattering process is invoked, but the final number of photons reaching the photocathode remains unchanged?

At the moment, I specify the scattering as follows:

#######################################

G4double Scatteringlength[26] = {62.5*m, 64.51612903225806*m, ...};

   G4double cosTeta_Baik = 0.88;

   G4double cosTetaBack_Baik = -0.2;

   G4double f_ratio_Baik = 0.9;


   G4MaterialPropertiesTable* BPTW = new G4MaterialPropertiesTable();

   BPTW->AddProperty("RINDEX", PhotonEnergyBaik, RefractiveIndexWBaik, 26);

   BPTW->AddProperty("ABSLENGTH", PhotonEnergyBaik, AbsorptionWBaik, 26);

   BPTW->AddProperty("MIEHG", PhotonEnergyBaik, Scatteringlength, 26);

   BPTW->AddConstProperty("MIEHG_FORWARD", cosTeta_Baik);

   BPTW->AddConstProperty("MIEHG_BACKWARD", cosTetaBack_Baik);

   BPTW->AddConstProperty("MIEHG_FORWARD_RATIO", f_ratio_Baik);

#######################################

Thank you in advance for any suggestions!