A Proposed Muon Facility in RAON/Korea

Abstract

Muons were discovered by Carl D. Anderson and Seth Neddermeyer at Caltech in 1936 [1] and later confirmed in 1937 [2]. Since then, the parity and charge conjugation violation in the decay of muons were discovered by Garwin, Lederman, and Weinrich [3]. The potential applications of polarized muons to condensed matter science were recognized by authors in the paper [3], by stating that “It seems possible that polarized positive and negative muons will become a powerful tool for exploring magnetic fields in nuclei, atoms and interatomic regions”. Their idea is later realized in many places now and this technique is commonly called the muon spin relaxation, rotation, and resonance (μSR from now on) [4]. At present, world-leading μSR facilities include Paul Scherrer Institute (PSI) in Switzerland, Tri-University Meson Facility (TRIUMF) in Canada, and Japan Proton Accelerator Research Complex (J-PARC) in Japan. These facilities provide continuous or pulsed polarized muons and depending on the purpose of the condensed matter science applications, one method is more appropriate than the other. On the other hand in the particle physics community, a long-waited discovery of Higgs particle is finally made in 2012 [5]. But unfortunately its properties are consistent with the prediction from the standard model of particle physics so far, indicating that there is a strong need to look at much higher energy scale than the energy scale that Large Hadron Collider (LHC) facility can directly look at, in order to look for the particle physics beyond standard model [6]. One way of looking at the higher energy scale experimentally is to look at charged lepton flavor violations (cLFV from now on) and muon is one of the most promising systems to look at cLFV at this moment. A rare isotope accelerator is under construction since 2012 in the Republic of Korea, near Daejeon city that is located at the central part of Korean pennsula [7]. We, a small group of high energy physicists is proposing a muon facility utilizing this rare isotope accelerator in order to realize a μSR facility for the first time in Korea and to realize a cLFV experiment also for the first time in Korea. In this presentation, first the major science goals of the project are discussed briefly, and a proposed muon facility for both μSR and cLFV science will be discussed.