2019/01/10 by F. Ambrosino, Ambrosino, F., R. Ammendola +153 · 1 citation
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High-Energy Particle Collisions Research #Instrumentation and Detectors (physics.ins-det) #Particle Detector Development and Performance #Particle physics theoretical and experimental studies #hep-ex #physics.ins-det
paper · pdf · doi:10.48550/arxiv.1901.03099
13 pages, 4 figures. Submitted as input to the 2020 update of the European Strategy for Particle Physics. v2: Included authors unintentionally omitted in v1
openalex publication_date 2019/01/10 · arxiv created 2019/05/22 · arxiv updated 2019/05/23 · openalex created_date 2022/10/29 · openalex updated_date 2026/07/28
Precise measurements of the branching ratios for the flavor-changing neutral current decays K→πνν can provide unique constraints on CKM unitarity and, potentially, evidence for new physics. It is important to measure both decay modes, K+→π+νν and KL→π0νν, since different new physics models affect the rates for each channel differently. The goal of the NA62 experiment at the CERN SPS is to measure the BR for the charged channel to within 10%. For the neutral channel, the BR has never been measured. We are designing the KLEVER experiment to measure BR(KL→π0νν) to ∼20% using a high-energy neutral beam at the CERN SPS starting in LHC Run 4. The boost from the high-energy beam facilitates the rejection of background channels such as KL→π0π0 by detection of the additional photons in the final state. On the other hand, the layout poses particular challenges for the design of the small-angle vetoes, which must reject photons from KL decays escaping through the beam exit amidst an intense background from soft photons and neutrons in the beam. Background from Λ→ nπ0 decays in the beam must also be kept under control. We present findings from our design studies for the beamline and experiment, with an emphasis on the challenges faced and the potential sensitivity for the measurement of BR(KL→π0νν).