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| NA48/NA62 | |
|---|---|
| Name | NA48/NA62 |
| Location | CERN, Geneva |
| Facility | Super Proton Synchrotron |
| Operation | 1990s–present |
| Experiments | NA48, NA62 |
| Purpose | Rare kaon decay studies |
NA48/NA62 The NA48/NA62 program at CERN operated experiments focused on rare kaon decays and precision tests of the Standard Model, performed at the Super Proton Synchrotron facility near Geneva. The program connected detector technologies from experiments like WA98 and NA31 with physics goals related to measurements pursued by collaborations such as KOTO and KLOE. It interfaced with accelerator projects including the Large Hadron Collider, the Proton Synchrotron, and international efforts at Fermilab and J-PARC.
The NA48/NA62 program encompassed two successive experiments mounted on the CERN North Area beamlines, exploiting neutral and charged kaon beams derived from the Super Proton Synchrotron. Drawing technical heritage from detectors used by NA31, NA34-2 and aligning physics priorities with groups like E787 and E949, the program aimed to probe rare processes mediated by flavor-changing interactions studied by theorists from institutions such as CERN Theory Division and universities including Cambridge University and Oxford University. Collaborating institutions ranged across Europe, Russia, and Asia, involving national laboratories like INFN, CEA Saclay, and Institute for High Energy Physics (Protvino).
The apparatus combined beamline elements from the Super Proton Synchrotron with detectors such as a magnetic spectrometer, a liquid krypton calorimeter, Cherenkov counters, and ring-imaging devices similar in concept to those used by HERMES, DELPHI, and LHCb. The liquid krypton calorimeter was modeled on techniques developed at NA31 and shared design principles with calorimeters from CMS and ATLAS upgrades. Tracking used drift chambers and straw chambers akin to technology deployed in CDF and COMPASS, while particle identification relied on Cherenkov radiators comparable to devices in SND and Belle. Trigger and data acquisition systems interfaced with timing systems developed by CERN IT and electronics groups that previously supported ALEPH and OPAL.
Primary goals included measurement of direct CP violation parameters in kaon decays and branching ratios for ultra-rare modes such as K+→π+νν̄ and K0_L→π0νν̄, complementing searches by experiments like KOTO and E949. The program addressed tests of the Cabibbo–Kobayashi–Maskawa matrix elements in conjunction with constraints from Belle II and BaBar, and it probed physics beyond the Standard Model comparable to searches by ATLAS and CMS for new flavor-changing interactions. Measurements were related to theoretical frameworks developed by researchers at CERN Theory Division, RWTH Aachen University, and MIT.
Data acquisition used high-rate triggers and streaming techniques similar to systems in LHCb and BaBar, with calibration campaigns drawing on procedures from LEP detectors and accelerator diagnostics from PS Booster. Analysis pipelines employed simulation tools like GEANT4 and fitting frameworks used by CDF and D0, while statistical methods referenced procedures from collaborations such as PDG compendia and software libraries maintained by CERN Openlab. Background suppression strategies leveraged veto systems analogous to those in KLOE and SND, and blind-analysis techniques mirrored practices at E787 and E949.
NA48 achieved precision measurements of direct CP violation parameters that complemented results from KTeV and influenced global fits reported by the Particle Data Group. NA62 produced leading limits and measurements on K+→π+νν̄ branching ratios, narrowing parameter space for models explored by theorists at Harvard University, Caltech, and Princeton University. Results constrained scenarios involving supersymmetry theories studied at SLAC and DESY, and had implications for heavy-flavor phenomenology related to experiments like LHCb and Belle. The program's measurements informed global electroweak fits performed by groups at CERN and impacted searches for rare processes also targeted by PS191 and NA62-KLEVER planning.
The upgrade path from NA48 to NA62 involved new beamline optics, a dedicated high-intensity charged-kaon beam inspired by work at Fermilab and BNL, and detector enhancements such as novel straw trackers and ring-imaging Cherenkov detectors developed in collaboration with groups from INFN, CERN and University of Zurich. Transition steps paralleled upgrade projects at LHCb Upgrade and Belle II, incorporating fast electronics and real-time processing pioneered by ATLAS and CMS upgrade teams. The evolution addressed higher rates and more stringent background rejection required for K+→π+νν̄ sensitivity goals set by advisory panels including members from ERC and national funding agencies like IN2P3.
The collaborations drew scientists from universities and institutes including CERN, Imperial College London, University of Liverpool, Max Planck Institute for Physics, Lomonosov Moscow State University, University of Tokyo, and TRIUMF. Governance followed models used by large-scale experiments such as ATLAS, CMS, and ALICE, with spokespersons, technical coordinators, and physics working groups coordinating tasks analogous to structures at LIGO and IceCube. Funding and oversight involved agencies like European Research Council, INFN, STFC, SNSF, and national ministries, and the collaboration participated in conferences such as EPS Conference on High Energy Physics and ICHEP.
Category:Particle physics experiments at CERN