Neutrinos from a Muon Storage Ring / Muon Collider

Neutrino flux codes and scattering models for [To appear]

This repository contains python classes and functions to perform weighted monte carlo (MC) simulations and modeling of the neutrino flux from a circular muon storage ring or muon collider. In addition, it contains integration methods to calculate the rates of electron scattering in a detector material using the alplib library to facilitate some helper classes.

Author: Adrian Thompson Contact: a.thompson@northwestern.edu

Requirements:

• alplib: https://github.com/athompson-git/alplib
• LFS for large flux files
• numpy, scipy
• tqdm

File Descriptions

nu_crosssection.py contains

• NeutrinoNucleonCCQE : An implementation of the CCQE cross section for arbitrary lepton final state using the form reported in Formaggio, Zeller

muon_collider_mc.py contains the monte carlo classes to simulate or model the flux and electron scattering of the neutrino beams sourced by the circular storage ring. In particular, it has

• NeutrinoFluxMuonRing class, with .simulate_fluxes_mc() and .simulate_flux() methods. The former performs geometric random sampling of the muon decay points along the ring and populates lists of 4-vectors with the neutrino momenta in the lab frame, while .simulate_flux() just populates the flux weights with a simple acceptance factor (see paper for details).

• EvESFromNeutrinoFlux computes the elastic neutrino electron scattering (E$\nu$ES) rates in a detector with a specified size and material, using the Material class defined in alplib (one of the dependencies).

muon_decay.py has the functions for the differential decay distributions for the daughter neutrinos of muon decay. Namely, d2NdydOmega_numu(y, theta, Emu, l_det, N_mu) and d2NdydOmega_nue(y, theta, Emu, l_det, N_mu) are the laboratory frame differential decay rates for the muon neutrino and electron anti-neutrino, respectively.