ANIS: All Neutrino Interaction Simulation

1
ANIS All Neutrino Interaction Simulation

• Marek Kowalski
• DESY-Zeuthen
• Workshop on Ultra High Energy Neutrino Telescopes
• Chiba, 30.7.2003

2
Content

• Introduction
• The implementation of the physics neutrino
  interaction, propagation,
• Some resulting event distributions

3
ANIS

• Event generator for neutrino events of all
  flavors
• C code, using the CLHEPHepMC library

4
ANIS
FluxDriver
HepMCEvent
Propagation
Interactions
HepMCEvent
Decays
n - events
FinalVolume
5
Interaction Processes

• Relevant Standard Model
• Processes are implemented
• CC, NC (structure function CTEQ5 two
  different extrapolations)
• Glashow resonance
• CC and NC cross-section data and final states
  are stored in tables.
• Tables of final states consisting of Feynman x
  and y generated before and sampled from by ANIS.

6
Flexible Design

• New processes easily added.
• Examples
• production of mini Black Holes
• Instantons,
• class SigmaNew public Sigma
• public
• double SigmaNewGetSigma
• void SigmaNewFillVertex

7
Tau decay

• Tau decay done using TAUOLA
• Polarization taken into account
• Table of final states (at rest) generated from
  which ANIS samples

8
Neutrino Propagation

• Preliminary Earth Model ( 3 km ice)
• Regeneration effects included
• - NC n N -gt X n
• - CC nt N -gt X t -gt n ( nm , ne)
• - Glashow resonance W -gt l nl
• - Any new processes
• All secondary neutrinos are taken into account
  and further propagated

9
Example Regeneration of nt
Ratio of neutrino flux at the detector to
neutrino flux at the surface (F(E)E-g)
g1
10
Once final volume reached

• Neutrino interaction simulated inside cylinder of
  variable size
• In case muons are generated further propagation
  necessary (e.g. using Dimas MMC, )

11
Some Event Distributions
Event rates of electron-neutrinos in a km3
detector
gt
gt
12
Neutrino-induced Muons

• Simulation of mono energetic nm.
• Detector 1.7 km deep in ice.
• Muon propagation done with MMC.

absorption
target
13
Some current limitations of ANIS

• Tau propagation done with abE approximation
  (valid up to EHE energies). Can be improved.
• Angle between neutrino lepton neglected during
  propagation. Only for final CC interaction
  included (important for resolution studies at low
  energies).
• Weighted events Physical flux (e.g atmospheric
• or AGN,..) is obtained by reweighting the
  events.

14
Conclusions

• (Rather) precise event generator existing
• for simulating neutrino events of all flavors
• Easily extendable to new physics