Search for $K^+\to\pi^+\nu\bar{\nu}$ at NA62

Understand

The decay $K^+\to\pi^+\nu\bar{\nu}$ is highly suppressed in the Standard Model (SM), while its rate can be predicted with minimal theoretical uncertainty.

• The branching ratio (BR) for this decay is thus a sensitive probe of the flavor sector of the SM; its measurement, however, is a significant experimental challenge.
• The primary goal of the NA62 experiment is to measure ${\rm BR}(K^+\to\pi^+\nu\bar{\nu})$ with 10% precision.
• NA62 took data in pilot runs in 2014 and 2015, reaching the design beam intensity.