HyperCP: A high-rate spectrometer for the study of charged hyperon and kaon decays

TL;DR

The HyperCP experiment at Fermilab used a high-rate magnetic spectrometer and advanced detection systems to study rare decays of charged hyperons and kaons, aiming to detect CP violation with high sensitivity.

Contribution

It introduced a high-rate spectrometer and data acquisition system capable of recording 231 billion events, enabling precise studies of hyperon and kaon decays for CP violation.

Findings

Achieved nearly identical acceptances for hyperons and antihyperons

Recorded 231 billion events in twelve months

Sensitive to CP violation at the level of 10^{-4}

Abstract

The HyperCP experiment (Fermilab E871) was designed to search for rare phenomena in the decays of charged strange particles, in particular CP violation in $\Xi$ and $\Lambda$ hyperon decays with a sensitivity of $10^{-4}$. Intense charged secondary beams were produced by 800 GeV/c protons and momentum-selected by a magnetic channel. Decay products were detected in a large-acceptance, high-rate magnetic spectrometer using multiwire proportional chambers, trigger hodoscopes, a hadronic calorimeter, and a muon-detection system. Nearly identical acceptances and efficiencies for hyperons and antihyperons decaying within an evacuated volume were achieved by reversing the polarities of the channel and spectrometer magnets. A high-rate data-acquisition system enabled 231 billion events to be recorded in twelve months of data-taking.