Neutrino Induced Coherent Pion Production

Daniel I. Scully
  1. Introduction
  2. Neutrinos & Neutrino Oscillations
  3. Neutrino Interactions
  4. Coherent Pion Production
  5. The T2K Experiment
  6. A Search for Coherent Pion Production at T2K
  7. Conclusions

This is the online version of my PhD thesis. You can also download a PDF version, or obtain the original publication from The University of Warwick or The British Library.

The analysis described here is not an official result of the T2K experiment. However, it was further developed and has since been published:

Measurement of coherent π+ production in low energy neutrino-Carbon scattering


Neutrino-induced coherent pion production is an important channel for the study of neutrino-nucleus interactions. It is both a dangerous background for νe oscillation experiments, and a critical component required for precise understanding of neutrino-nucleus pion production in general.

The body of experimental evidence for coherent pion production at high neutrino energies is reviewed. This data is described well by the Rein-Sehgal model, which is described and studied. In light of recent low energy limits set below the Rein-Sehgal model cross-section an alternative low energy model, the Alvarez-Ruso model, was implemented in the neutrino interaction simulation GENIE. The results of this simulation are compared with those from the Rein-Sehgal model, and briefly with those from other models.

Finally, a search for νμ-induced charged-current (CC) coherent pion production on 12C was conducted at a mean neutrino energy of 0.86 GeV, using data from the T2K experiment's off-axis near detector. A 3.0 σ excess of events was found above the background prediction, constituting the first experimental evidence of CC coherent pion production below 7 GeV. Preliminary attempts to interpret this excess in the context of the Rein-Sehgal and Alvarez-Ruso models found cross-sections consistent with the limits set by SciBooNE.