The NA62 experiment

Birmingham group: T Bache, Dr F Gonnella, Dr E Goudzovski, J Henshaw, Prof C Lazzeroni, Dr N Lurkin, Dr D Munday, Dr A Romano, Dr A Sergi, J Swallow

The NA62 experiment at CERN is dedicated to stringent tests of the Standard Model (SM) and precision searches for new physics beyond the SM via studies of rare decays, and searches for the forbidden decays, of the charged kaon. It is a fixed-target experiment using a high intensity 400 GeV/c proton beam extracted from the CERN SPS accelerator to produce a secondary 75 GeV/c kaon beam.

The first NA62 physics run took place in 2016–2018, and will be followed by another run in 2021–2024. The experiment aims to record information of about 1013 charged kaon decays in a region contained in a 80 metre long vacuum tank.

The central goal of the experiment is the measurement 10% precision of the rate of the ultra-rare decay K+→π+νν, with the expected SM branching ratio below 10−10. The SM contribution to the decay rate comes from penguin and box diagrams. Its dominant part is due to top quark exchange, which leads to the highest CKM suppression. This decay is an ideal place to search for new physics: its branching ratio is low and precisely predicted branching within the SM, and therefore new physics can potentially give sizable deviations.

The wider NA62 physics programme includes precision searches for lepton flavour and number violation in kaon decays (this aspect is led by the Birmingham group), searches for production and decays of the possible hidden-sector mediators (dark scalars, dark photons and heavy neutral leptons), lepton universality tests and studies of rare decays of kaons and pions.

The Birmingham group is one of the largest in the collaboration, and is involved in:
  • maintenence and operation of the KTAG Cherenkov detector tagging the incoming kaons;
  • development and operation of the L0 (firmware) and L1 (software) trigger systems;
  • development and support of the run control system;
  • development and support of the core software;
  • a wide range of physics analyses, including searches for lepton flavour and lepton number violating kaon decays, searches for heavy neutral lepton production and decays, and rare kaon and pion decay measurements.

For general information about NA62, see:

NA62 detector construction (2012)

The KTAG subdetector built by the UK group

General view of the NA62 detector