Measuring the masses of the charged hadrons using a RICH as a precision velocity spectrometer

TL;DR

This paper reports on high-precision mass measurements of charged hadrons using a RICH detector as a velocity spectrometer, achieving 0.1% accuracy and addressing systematic effects for future precise mass determinations.

Contribution

It introduces a method to measure hadron masses with high precision using RICH detectors and analyzes systematic effects for improved accuracy.

Findings

Achieved 0.1% mass measurement precision.

Developed techniques to control RICH radius measurement to 10^{-4}.

Demonstrated systematic understanding for future mass measurements.

Abstract

The Selex experiment measured several billion charged hadron tracks with a high precision magnetic momentum spectrometer and high precision RICH velocity spectrometer. We have analyzed these data to simultaneously measure the masses of all the long lived charged hadrons and anti-hadrons from the pi to the Omega using the same detector and technique. The statistical precision achievable with this data sample is more than adequate for 0.1% mass measurements We have used these measurements to develop and understand the systematic effects of a RICH as a precision velocity spectrometer with the goal of measuring 10 masses with precision ranging from 100 KeV for the lightest to 1000 KeV for the heaviest. This requires controlling the radius measurement of RICH rings to the ~10^{-4} level. Progress in the mass measurements and the required RICH analysis techniques developed are discussed.