The NA62 experiment at CERN

Birmingham group: Prof E Goudzovski, Prof C Lazzeroni, Dr B Bloch-Devaux, Dr JR Fry, Dr F Gonnella, Dr T Husek, Dr A Romano, C Kenworthy, C Sam, J Sanders, A Tomczak
NA62 is a flavour physics experiment at CERN dedicated to stringent tests of the Standard Model (SM) and exploration of new physics beyond the SM via studies of rare decays and searches for forbidden decays of the charged kaon. The main goal of the experiment is the measurement of the ultra-rare decay K+→π+νν in order to provide a unique stringent SM test complementary to those performed with heavy meson decays.

During Run 1 in 2016–2018, the NA62 experiment collected world's largest data sample of charged kaon decays. Information about 6×1012 kaon decays in a region contained in a 80 metre long vacuum tank has been recorded, at a typical beam intensity of 500 MHz. Following a significant upgrade, the experiment restarted data collection ("Run 2") in 2021. The Run 2 dataset collected so far already exceeds the Run 1 dataset.

In 2021, the NA62 collaboration published a 3σ evidence for the K+→π+νν decay based on the Run 1 dataset. In September 2024, the collaboration announced the first observation of this process with a 5σ significance using the 2016–2022 dataset. This result has made K+→π+νν the rarest particle decay ever observed. The next goal is a measurement of the decay rate to a 15% precision.

The wider NA62 physics programme includes precision measurements of rare kaon and pion decays, high-sensitivity tests of lepton flavour and number conservation in kaon decays, lepton universality tests, and searches for production and decays of the possible hidden-sector mediators (dark scalars, dark photons and heavy neutral leptons), including dedicated operation in beam-dump mode. Several aspects of this programme are led by the Birmingham group.

We play prominent roles in the collaboration and we are responsible for:
  • maintenance and operation of the KTAG (a fast Cherenkov kaon tagger detector);
  • maintenance and operation of the High Level Trigger;
  • development and support of core offline software;
  • a range of physics analyses, including several aspects of the flagship K+→π+νν measurement, precision measurement of rare decays, searches for lepton flavour/number violation, and searches for hidden sector mediator production and decays.

The Birmingham NA62 group has been funded by the STFC (via Particle Physics consolidated grants and an Ernest Rutherford fellowship), ERC (Advanced Grant 268062, Starting Grant 336581), the Royal Society (two University Research Fellowships), the European Commission (Marie Sklodowska-Curie grants 271987, 701386, 101023808), and via CERN and IPPP scientific associateships.

Please contact Prof Evgueni Goudzovski for further information.

External links:

NA62 detector construction (2012)


The KTAG subdetector built by the UK groups


General view of the NA62 setup