23 Oct/20
11:00 - 12:00 (Europe/Zurich)

Perspectives for high-intensity kaon physics at the SPS

Precision measurements of the branching ratios (BRs) for rare kaon decays can provide unique constraints on CKM unitarity and may reveal the existence of new physics. Decays such as $K^+\to\pi^+\nu\bar{\nu}$ and $K_L\to\pi^0\nu\bar{\nu}$, are strongly suppressed in the Standard Model, while their rates can be calculated with very small theoretical uncertainties. These BRs for these decays are potentially sensitive to high mass scales, and several models of new physics predict large deviations from the Standard Model. Following upon NA62's successful application of the in-flight technique to measure ${\rm BR}(K^+\to\pi^+\nu\bar{\nu})$, we envision a comprehensive program for the study of the rare decay modes of both $K^+$ and $K_L$ mesons, to be carried out with high-intensity kaon beams from the CERN SPS in multiple phases, including both an experiment to measure ${\rm BR}(K^+\to\pi^+\nu\bar{\nu})$ at the 5% level and an experiment to measure ${\rm BR}(K_L\to\pi^0\nu\bar{\nu})$ at the 20% level. The detectors could also be reconfigured to allow measurements of $K_L$ decays with charged particles, such as $K_L\to\pi^0\ell^+\ell^-$.

In addition to the careful optimization of the design of the primary and secondary beamlines, the experimental program requires advances in precision tracking at high rate, high-efficiency calorimeters and veto detectors with excellent PID capabilities, and innovative readout systems to guarantee excellent time resolution and separation of overlapping signals. In this seminar the physics case for this program, the experimental challenges faced and the status of the design studies in progress will be discussed. 

Zoom connection details are given in the invitation email.