Rabi-oscillation spectroscopy of the hyperfine structure of muonium atoms

Nishimura, Shoichiro*; Torii, Hiroyuki*; Fukao, Yoshinori*; Ito, Takashi; Iwasaki, Masahiko*; Kanda, Sotaro*; Kawagoe, Kiyotomo*; Kawall, D.*; Kawamura, Naritoshi*; Kurosawa, Noriyuki*; et al.

Physical Review A, 104(2), p.L020801_1 - L020801_6, 2021/08

https://doi.org/10.1103/PhysRevA.104.L020801

Negative muonium ion production with a C12A7 electride film

Otani, Masashi*; Fukao, Yoshinori*; Futatsukawa, Kenta*; Kawamura, Naritoshi*; Matoba, Shiro*; Mibe, Tsutomu*; Miyake, Yasuhiro*; Shimomura, Koichiro*; Yamazaki, Takayuki*; Hasegawa, Kazuo; et al.

Journal of Physics; Conference Series, 1350, p.012067_1 - 012067_6, 2019/12

https://doi.org/10.1088/1742-6596/1350/1/012067

Negative muonium atom (ee, Mu) has unique features stimulating potential interesting for several scientific fields. Since its discovery in late 1980's in vacuum, it has been discussed that the production efficiency would be improved using a low-work function material. C12A7 was a well-known insulator as a constituent of alumina cement, but was recently confirmed to exhibit electric conductivity by electron doping. The C12A7 electride has relatively low-work function (2.9 eV). In this paper, the negative muonium production measurement with several materials including a C12A7 electride film will be presented. Measured production rate of the Mu were 10/s for all the Al, electride, and SUS target. Significant enhancement on electride target was not observed, thus it is presumed that the surface condition should be more carefully treated. There was no material dependence of the Mu averaged energy: it was 0.20.1keV.

Muon profile measurement after acceleration with a radio-frequency quadrupole linac

Otani, Masashi*; Sue, Yuki*; Fukao, Yoshinori*; Futatsukawa, Kenta*; Kawamura, Naritoshi*; Mibe, Tsutomu*; Miyake, Yasuhiro*; Shimomura, Koichiro*; Yamazaki, Takayuki*; Iijima, Toru*; et al.

Journal of Physics; Conference Series, 1067(5), p.052012_1 - 052012_7, 2018/09

https://doi.org/10.1088/1742-6596/1067/5/052012

We have measured the muon beam profile after acceleration using a radio frequency quadrupole linac (RFQ). Positive muons are injected to an aluminum degrader and negative muoniums (Mu) are generated. The generated Mus are extracted by an electrostatic lens and accelerated to 89 keV by the RFQ. The accelerated Mus are transported to a beam profile monitor (BPM) through a quadrupole magnet pair and a bending magnet. The BPM consists of a micro-channel plate, a phospher screen, and a CCD camera. Measured profile in the vertical direction is consistent to the simulation. This profile measurement is one of milestones for realizing a muon linac for measurement of the muon anomalous magnetic moment at the Japan Proton Accelerator Research Complex.

Result of the first muon acceleration with radio frequency quadrupole

Kitamura, Ryo*; Otani, Masashi*; Fukao, Yoshinori*; Futatsukawa, Kenta*; Kawamura, Naritoshi*; Mibe, Tsutomu*; Miyake, Yasuhiro*; Yamazaki, Takayuki*; Kondo, Yasuhiro; Hasegawa, Kazuo; et al.

Proceedings of 9th International Particle Accelerator Conference (IPAC '18) (Internet), p.1190 - 1193, 2018/06

https://doi.org/10.18429/JACoW-IPAC2018-TUPAL076

Muon acceleration using radio-frequency accelerators makes it possible to precisely measure the muon anomalous magnetic moment and the electric dipole moment. The first muon acceleration was demonstrated using a radio-frequency quadrupole (RFQ) linac. A negative muonium ion (Mu) with less than 2 keV energy was produced from an incident muon with 3 MeV energy using a thin aluminum foil target in order to cool the muon beam for the acceleration, because the designed input energy of the RFQ is 5.6 keV. The Mu was first accelerated to 5.6 keV using an electrostatic accelerator, and was subsequently accelerated to 90 keV using the RFQ. This accelerated Mu was selected using a diagnostic beam line and was identified based on Time-Of-Flight measurements.

Current preparation and prospects of the muon acceleration test with RFQ in J-PARC

Kitamura, Ryo*; Otani, Masashi*; Kondo, Yasuhiro; Bae, S.*; Choi, S.*; Fukao, Yoshinori*; Futatsukawa, Kenta*; Hasegawa, Kazuo; Iinuma, Hiromi*; Ishida, Katsuhiko*; et al.

Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.100 - 103, 2017/12

Muon acceleration is an important technique in exploring the new frontier of physics. A new measurement of the muon dipole moments is planned in J-PARC using the muon linear accelerator. The low-energy (LE) muon source using the thin metal foil target and beam diagnostic system were developed for the world's first muon acceleration. Negative muonium ions from the thin metal foil target as the LE muon source was successfully observed. Also the beam profile of the LE positive muon was measured by the LE-dedicated beam profile monitor. The muon acceleration test using a Radio-Frequency Quadrupole linac (RFQ) is being prepared as the first step of the muon accelerator development. In this paper, the latest status of the first muon acceleration test is described.

First trial of the muon acceleration for J-PARC muon g-2/EDM experiment

Kitamura, Ryo*; Otani, Masashi*; Fukao, Yoshinori*; Kawamura, Naritoshi*; Mibe, Tsutomu*; Miyake, Yasuhiro*; Shimomura, Koichiro*; Kondo, Yasuhiro; Hasegawa, Kazuo; Bae, S.*; et al.

Proceedings of 8th International Particle Accelerator Conference (IPAC '17) (Internet), p.2311 - 2313, 2017/06

https://doi.org/10.18429/JACoW-IPAC2017-TUPVA097

Muon acceleration is an important technique in exploring the new frontier of physics. A new measurement of the muon dipole moments is planned in J-PARC using the muon linear accelerator. The low-energy (LE) muon source using the thin metal foil target and beam diagnostic system were developed for the world's first muon acceleration. Negative muonium ions from the thin metal foil target as the LE muon source was successfully observed. Also the beam profile of the LE positive muon was measured by the LE-dedicated beam profile monitor. The muon acceleration test using a Radio-Frequency Quadrupole linac (RFQ) is being prepared as the first step of the muon accelerator development. In this paper, the latest status of the first muon acceleration test is described.

New muonium HFS measurements at J-PARC/MUSE

Strasser, P.*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; Ito, Takashi; Iwasaki, Masahiko*; et al.

Hyperfine Interactions, 237(1), p.124_1 - 124_9, 2016/12

https://doi.org/10.1007/s10751-016-1331-4

Development of muon linac for the muon g-2/EDM experiment at J-PARC

Otani, Masashi*; Mibe, Tsutomu*; Fukao, Yoshinori*; Saito, Naohito; Yoshida, Mitsuhiro*; Kitamura, Ryo*; Kondo, Yasuhiro; Iwashita, Yoshihisa*

Proceedings of 6th International Particle Accelerator Conference (IPAC '15) (Internet), p.2541 - 2544, 2015/06

https://doi.org/10.18429/JACoW-IPAC2015-WEPWA023

Muon acceleration is beyond our experiences. It enables us to measure the muon anomalous magnetic moment with an accuracy of 0.1 ppm and search for electric dipole moment with a sensitivity of 10 ecm to explore beyond Standard Model of elementary particle physics. We are developing a linac dedicated to the muon acceleration and planning to try the muon acceleration by utilizing slow negative muonium production. This paper described status of these developments.

Azimuthal correlations of electrons from heavy-flavor decay with hadrons in and Au+Au collisions at = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.

Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04

https://doi.org/10.1103/PhysRevC.83.044912

Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to collisions.

Ultra-slow muon acceleration using an RFQ towards the g-2/EDM experiment at J-PARC

Kondo, Yasuhiro; Otani, Masashi*; Fukao, Yoshinori*; Hasegawa, Kazuo; Hayashizaki, Noriyosu*; Ishida, Katsuhiko*; Iwashita, Yoshihisa*; Kawamura, Naritoshi*; Kitamura, Ryo*; Mibe, Tsutomu*; et al.

no journal, , 

The muon linear accelerator for the muon g-2/EDM experiment in J-PARC is being developed. As the first step of the muon acceleration, the muon acceleration with J-PARC RFQ (Radio-Frequency Quadrupole)-II plans to be demonstrated at H-line of J-PARC MLF. The slow muon will be obtained by the deceleration using the thin metal foil target in the RFQ acceleration test. The intensity of the decelerated muon by the thin metal foil was measured. Based on this result, the beam intensity in the RFQ test at H-line is estimated to be a few /sec. The particle simulation of the RFQ and the following beam diagnostics system is conducted, and it is shown that the emittance measurement at the RFQ exit using the micro-channel plate based beam profile monitor is feasible.