High precision beam momentum determination in a synchrotron using a spin resonance method

TL;DR

This paper presents a highly precise method for determining the momentum of a deuteron beam in a synchrotron using spin resonance, crucial for accurate eta meson mass measurements.

Contribution

It introduces a novel application of spin resonance to measure beam momentum with unprecedented precision in a synchrotron environment.

Findings

Achieved momentum measurement precision of dp/p < 10^-4 at ~3 GeV/c.

Demonstrated the feasibility of using spin resonance during standard experiments.

Discussed sources of error and practical implementation considerations.

Abstract

In order to measure the mass of the eta meson with high accuracy using the d+p -> 3He+eta reaction, the momentum of the circulating deuteron beam in the Cooler Synchrotron COSY of the Forschungszentrum Juelich has to be determined with unprecedented precision. This has been achieved by studying the spin dynamics of the polarized deuteron beam. By depolarizing the beam through the use of an artificially induced spin resonance, it was possible to evaluate its momentum p with a precision of dp/p < 10-4 for a momentum of roughly 3 GeV/c. Different possible sources of error in the application of the spin resonance method are discussed in detail and its possible use during a standard experiment is considered.