NA62

NA62
Name	NA62
Location	CERN
Established	2007

NA62 is a fixed-target particle physics experiment at CERN designed to study rare kaon decays. It operates on the North Area beamline using a high-intensity charged kaon beam derived from the Super Proton Synchrotron. The experiment integrates technologies and expertise from institutions such as University of Birmingham, ETH Zurich, and INFN groups, building on heritage from the NA48 program and informed by results from KOTO, E787, and E949.

Overview

NA62 explores processes sensitive to physics beyond the Standard Model by measuring branching ratios of ultra-rare decays of charged kaons produced at CERN using the Super Proton Synchrotron and extracted via the H8 beamline. The collaboration includes researchers from laboratories like CERN, INFN, KEK, TRIUMF, University of Oxford, Moscow State University, Institute for High Energy Physics (Protvino), and JINR. NA62 leverages detector concepts developed in experiments such as NA48/2, KLOE, LHCb, and Belle II to achieve high background suppression and precise timing.

Experimental Setup

The experimental apparatus comprises a beamline, tracking systems, calorimetry, particle identification, and veto detectors. The charged kaon beam is produced by protons from the Super Proton Synchrotron impinging on a production target in the North Area (CERN), transported through the H8 beamline to the detector complex. The upstream beam instrumentation includes a differential Cherenkov counter inspired by designs used at CERN PS and BNL AGS, while the downstream tracking uses a straw-tube spectrometer housed in a vacuum tank reminiscent of systems from NA48. PID is provided by a ring-imaging Cherenkov detector adapted from concepts tested at SPS test beam stations and calorimetry by a liquid-krypton calorimeter refurbished from the NA48 program. Vetoing systems include large-angle photon vetoes modeled on detectors from KOTO and a muon veto system drawing on technology from LHCb and CMS muon detectors. Trigger and data acquisition integrate electronics and firmware developments from ALICE, ATLAS, and CMS upgrade efforts.

Physics Goals and Results

Primary physics goals include a precise measurement of the branching ratio for the charged kaon decay to a pion and a neutrino-antineutrino pair, a process predicted by the Standard Model with strong sensitivity to contributions from supersymmetry, leptoquark scenarios, and models with minimal flavor violation. NA62 has produced constraints that complement searches at LHC experiments like ATLAS and CMS and precision flavor results from Belle and BaBar. Secondary programs probe lepton-flavor and lepton-number violating decays analogous to searches performed by MEG and COMET, and searches for heavy neutral leptons related to efforts at PS191 and T2K. Published results include limits on branching ratios for K+ → π+νν̄ and searches for dark-sector particles motivated by theories connected to axion-like particles, dark photons, and portal models that also guide experiments such as SHINE and SeaQuest.

Data Analysis and Methodology

Data processing employs reconstruction algorithms, multivariate analysis, and blind analysis techniques similar to those used at LHCb, ATLAS, and CMS. Event selection relies on kinematic constraints, particle-identification likelihoods, and veto logic comparable to methodologies from NA48/2 and KLOE. Background estimation uses control samples and sideband methods analogous to analyses at BaBar and Belle II. Systematic uncertainties are constrained with calibration campaigns referencing measurements from CERN SPS test beams and detector alignments guided by procedures from ALEPH and DELPHI. Statistical interpretation uses frequentist and Bayesian techniques consistent with practices from Particle Data Group summaries and global fits employed by collaborations such as CKMfitter and UTfit.

Collaborations and Funding

The collaboration draws institutions from Europe, Asia, and the Americas, including universities and national laboratories such as CERN, INFN, Imperial College London, University of Liverpool, University of Toronto, Kyoto University, Osaka University, Peking University, IHEP Beijing, University of Chicago, and FNAL. Funding and oversight come from agencies like the European Research Council, national research councils including UKRI, Swiss National Science Foundation, National Natural Science Foundation of China, Japanese Ministry of Education, Culture, Sports, Science and Technology, INFN, and project support coordinated with CERN Directorate and regional funding bodies that also support projects such as LHCb and ALICE.

Impact and Future Plans

NA62 influences theoretical and experimental directions in flavor physics, complementing precision programs at LHCb, Belle II, and neutrino experiments like DUNE. Results inform model-building in contexts explored by researchers at Princeton University, MIT, and Institut de Physique Théorique (IPhT), and motivate searches in dark-sector experiments such as FASER and SHiP. Upgrades under consideration include improved photon vetoes, upgraded readout electronics following developments at CERN EP Department, and trigger enhancements coordinated with SPS beam improvements. Prospective synergy with proposals for next-generation kaon facilities and continued comparison with results from KOTO and collider searches will guide the collaboration's roadmap toward higher sensitivity and broader searches for rare processes.

Category:Particle physics experiments