New frontier with Laser spectroscopy of Muonium

Okayama University

RikenA， The University of British ColumbiaB，

KEKC， Peking UniversityD

Satoshi UetakeKoji Yoshimura

Collaborators:T. Hiraki, H. Hara, Y. Imai, K. IshidaA, S. KamalB, N. KawamuraC, Y. MaoD, T. Masuda, T. MibeC, Y. MiyakeC, Y. Miyamoto, M. OtaniC, K. ShimomuraC,K. SuzukiC, T. YamazakiC, M. YoshidaC, K. Yoshimura, M. Yoshimura, C. ZhangD

Introduction to Okayama University Group Brief introduction of the SPAN project Macro-coherent amplificationFundamental Physics using Hydrogen-like atoms History and present of Hydrogen spectroscopy Muonium spectroscopy and New physics Muonium 1S-2S Laser Spectroscopy project at J-PARC Motivation and goal Project overview and time schedule Recent status: simulation study and hydrogen testFuture prospects High brightness muon source by 1S-2S ionization of Mu High power 244 nm laser systemSummary

Outline

Okayama-U Group

・Particle physics, Cosmology・Atomic/Molecular/Optical Phys・Nuclear Physics・Physical chemistry

K. Yoshimura, M. Yoshimura, N. Sasao, T. Masuda, T. Hiraki, S. Uetake, H. Hara, Y. Imai, K. Imamura, A. Yoshimi, Y. MiyamotoStudents： K. Okai, H. Kaino, A. Fujieda, T. Kobayakawa, M. Kobayashi, A. Gomi, H. Hiruma, S. Yamamoto

11 staff8 students

SPAN: SPectroscopy with Atomic NeutrinoMeasure important neutrino parameters using atoms/molecules Radiative Emission of Neutrino Pair: RENP

「原子を用いたニュートリノ質量分光」, 高エネルギーニュース，33, 99 (2014)

β decay of 3H

18100 keV# of electron

Endpoint Spectrum

XeEnergy [eV]

0

8.315 18.6

0

Energy [keV]

−1−2E − 18.6 keV

(cf.)

Photon Energy [eV]

Rat

e [H

z]

1 2 3 4

Endpoint Spectrum

4.1565 4.1570 4.1575 eV

0.02

0.04

0.06

0.08

m0=1 meVm0=10 meVm0=50 meVNH/ IH

145 GHz

0

two-photonemission

RENP

−0.1Freq. [GHz]

Neutrino Mass Spectroscopy with Atoms and LasersStimulate the process with laser

Neutrino mass difference of 1 meV → Corresponds to freq. shift of 100 MHzFrequency Resolution of Laser :

Y. Miyamoto, SU, et al., Prog. Theor. Exp. Phys. 2015, 081C01 (2015)

Demonstration of Macro-Coherent Amplification

PPSLT LBO

CW864 nmECLD+TA

CW684 nmECLD

PPLN

Nd:YAG

Nd:YAG

SHG532

13864.59µm

4.59 µm

5.05 µm

684nm

532nm

LBO

KTA1064

p-H2

Damper

LPFs

Monochromator

MCTDetector

4.59 µm

5.05 µm

Coherence preparationwith Raman process

Two-photonis triggered with4.59 um laser

532 nm684 nm

(v = 1)

(v = 0)

Succeeded to Enhance E1×E1 two-photon emission rate : 1019 Gain

Macro coherent E1×M1 two-photon, three-photon emission; solid-state target development

Okayama-U group interests:Fundamental Physics using state-of-the-art AMO technique → Manipulation of quantum state of atoms/molecules by lasers

Application of Macro-coherent amplification to RENP processDetail study of Electroweak to TeV scale physics in Laboratory Determine yet unknown neutrino parameters (SPAN project) Development of narrow/high-power laser system

340 nK~Tc

806040200

Num

ber o

f ato

ms

x103

40

20

0-60 -40 -20 0 20 40

Frequency [kHz]

~140 nK

goal

tool

Laser Spectroscopy of Bose-Einstein condensation(previous work)

(AMO: Atomic/Molecular/Optical)

New!!Precision test of electroweak theoryby laser spectroscopy of Muonium

Introduction to Okayama University Group Brief introduction of the SPAN project Macro-coherent amplificationFundamental Physics using Hydrogen-like atoms History and present of Hydrogen spectroscopy Muonium spectroscopy and New physics Muonium 1S-2S Laser Spectroscopy project at J-PARC Motivation and goal Project overview and time schedule Recent status: simulation study and hydrogen testFuture prospects High brightness muon source by 1S-2S ionization of Mu High power 244 nm laser systemSummary

Outline

Hydrogen-like Atoms: Simplest bound-system Precise theoretical calculation is possible →Quantum Mechanics / QED development Energy levels correspond to forces between positive/negative charge

Coulomb potential

Spectroscopy of One-Electron Atoms

1s1/21s1/2

2p1/2

2p3/22s1/2

n = 1

n = 2

1s

2s, 2p

Bohr Dirac QED

2s1/2, 2p1/2

2p3/2

……

potential ofCoulomb+new force

Electroweak

Hadronic effect

Compare Precise experiment / theoretical calculation↓

Precision test of electroweak theory may be possible

1S-2S Laser Spectroscopy of Hydrogen

T. W. Hänsch, Nobel Lecture Slides (2005), with recent results

1999： Optical frequency comb invention

1960： Laser invention

uncertainty [exp]: 11 Hz [1]

[1] Phys. Rev. Lett. 110, 230801 (2013)

T. W. Hänsch [theo] 44 kHz [2]

→due to proton structure (proton radius puzzle)3 order discrepancy between exp & theory

[2] Eur. Phys. J. 172, 109 (2009)

Proton: compositparticle of 3 quarks

quark

Hydrogen vs Pure leptonic systemH [Hydrogen (ep)] ： lifetime >1034 yrsBound system of Proton & Electron

Mu [Muonium (μ+e–)]：lifetime 2.2μsBound system of positive muon & electron

lepton(=point charge)

quarklepton

Yes

NoLarge

Very Difficult

Composite particle of Hadrons and lepton

Components / Structure

only Leptons(point charges)

Precise theoreticalcalculation

Uncertainty fromNuclear structure

・QED・Electroweak・Found discrepancy between theo. & exp.?→May be an evidence of Beyond the standard model (new Yukawa-type potential)

Vacuum polarization(hadronic) +232.7(1.4) HzSov. J. Nucl. Phys. 53, 626(1991)

1st order Electroweak -65 HzPRA 53, 2953 (1996)

Ultra-precision Test

A new scalar or vector boson coupled to electron and muon gives rise to a Yukawa-type potential:

Constraints from astrophysics (e.g. stellar cooling effects) are very strongNew physics search through Mu spectroscopy: Can be done in a laboratory experiment Independent of a specific model

Spin-independent Dark Forces Spin-dependent Dark Forces

10- 13

10- 11

10- 9

10- 7

10- 5

10- 3

PresentMu 1S–2S(9.8 MHz)

Mu 1S–2S (10 kHz)

C. Frugiuele et al., Phys. Rev. D 100, 015010 (2019)

10-3 10-1 10110-510-18

10-16

10-14

10-12

10-10

10-8

10-6

10-4

10-2

100

10-8 10-6 10-4 10-2 100 102 104 106

Ps

HPresentMu 1S-HFS120 ppb

Mu 8 Hz

New physics New Physics

Constraints fromastrophysics

Introduction to Okayama University Group Brief introduction of the SPAN project Macro-coherent amplificationFundamental Physics using Hydrogen-like atoms History and present of Hydrogen spectroscopy Muonium spectroscopy and New physics Muonium 1S-2S Laser Spectroscopy project at J-PARC Motivation and goal Project overview and time schedule Recent status: simulation study and hydrogen testFuture prospects High brightness muon source by 1S-2S ionization of Mu High power 244 nm laser systemSummary

Outline

This project is funded byJSPS KAKENHI Grant-in-Aid for Scientific Research (S) [FY2019-2023]S. Uetake (PI), K. Shimomura, M. Yoshida, T. Yamazaki, M. Yoshimura

About to submit S type research project of J-PARC MLF

Mu Energy Level

Present Precision and Our Goal

Laser Spectroscopy

mass uncertaintymass uncertainty

ppb: 10–9

mass

1S-2S Laser Spectroscopy

Microwave

mass

1S-HFS microwavespectroscopy

Uncertainty u[ ]Theo. : 1.4 MHz(comes from mass uncertainty of 120 ppb)

Uncertainty u[ ]Theo. : 515 Hz [2](comes from mass uncertainty of 120ppb)

Electroweak Frequency shift: -65 Hz[2] M. I. Eides, Phys. Lett. B 795, 113 (2019)

1S-2S Goalu[ ]exp.: 10 kHz(RAL 1999: 9.8 MHz[1])

Goal (a) : 1S-2S SpectroscopyReduce the mass uncertainty

120 ppb 1 ppb

11 Hz

[1] V. Meyer et al., PRL 84, 1136 (2000)

MuSEUM Goalu[ ]exp.: 8 Hz(LAMPF1998: 53 Hz)

Goal (b) ：1S-HFS SpectroscopyPrecision Test of EW Theory &

Search BSM physics

Latest 1S-2S measurement (@Rutherford Appleton Laboratory, 1999)VOLUME 84, NUMBER 6 P H Y S I C A L R E V I E W L E T T E R S 7 FEBRUARY 2000

Measurement of the 1s-2s Energy Interval in Muonium

V. Meyer,1 S. N. Bagayev,5 P. E. G. Baird,2 P. Bakule,2 M. G. Boshier,4 A. Breitrück,1 S. L. Cornish,2 S. Dychkov,5G. H. Eaton,3 A. Grossmann,1 D. Hübl,1 V. W. Hughes,6 K. Jungmann,1 I. C. Lane,2 Yi-Wei Liu,2 D. Lucas,2

Y. Matyugin,5 J. Merkel,1 G. zu Putlitz,1 I. Reinhard,1 P. G. H. Sandars,2 R. Santra,1 P. V. Schmidt,1 C. A. Scott,3W. T. Toner,2 M. Towrie,3 K. Träger,1 L. Willmann,1 and V. Yakhontov1

p.1136

Retroreflector!µ+

AlexandriteLaser

VacuumApparatus

Tripler Fast BeamDiagnostics

Cavity ControlElectronics

MCP

732 nm244 nm

Uncerntainty from ResidualDoppler → 3.4 MHzPulse laser was usedlinewidth ~ 10 MHz

0

0.2

0.4

0.6

0.8

1

1.2

1.4

640 660 680 700 720νLaser-νIodine [MHz]

Even

ts p

er L

aser

Pul

se [1

0-4 ]

MuoniumF=1 → F=1

Signal

Theory

~20 MHz

Previous Muonium Laser Spectroscopy

No sophisticated optical frequency measurement technique available# of μ：105μ+ /s； # of Mu in interaction region：1.5 /pulse

Results：2 455 528 941.0(9.8) MHz

1S-2S Laser Spectroscopy Plan: Overview

2009 2012 2017 2020

Worldʼs highest intensity pulsed muon beam source108 µ/s beam will be available from 2020

★

Phase 1 (uncertainty 1 MHz, ~Mar. 2021)：S2 area (Starts from 2020B)Phase 2 (uncertainty 10 kHz, ~Mar. 2024)：S2 area and H1 area

# of muon

x14

RAL1999

J-PARC MLF

1S-2S Laser Spectroscopy Plan: Overview

2009 2012 2017 2020

Worldʼs highest intensity pulsed muon beam source108 µ/s beam will be available from 2020

★

Phase 1 (uncertainty 1 MHz, ~Mar. 2021)：S2 area (Starts from 2020B)Phase 2 (uncertainty 10 kHz, ~Mar. 2024)：S2 area and H1 area

# of muon

x14

RAL1999

J-PARC MLF

G. A. Beer et al., Prog. Theor. Exp. Phys. 2014, 091C01

Efficient muonium production by Silica aerogel

Total Mu yield: 3%0

500

1000

1500

2000

2500

3000

Region 110 < z < 20 (mm) # of muonium

(in laser volume):RAL1999 1.5 /pulseH-Line ~104 /pulse

1S-2S Laser Spectroscopy Plan: Overview

Aerogel

Surfacemuon beam

244 nm opticalcavity

SOAlens

LensElectrostaticmirror

Bending magnet

scintillator

MCP

Frequency stabilizationOptical fiber comb

Laser diode976 nmcw, 30 mW

SHG2.4W@488nm

FHG0.5W@244nm

Ionization355nm Nd:YAG

Fiber AmplifierNarrow-linewidth Laser system

2S Muonium Detection 244 nm244 nm355 nmIonization

1S-2S Laser Spectroscopy Plan: OverviewTime schedule

Develop CW High-power 244nm laser

S2 area preparation@J-PARC

Phase 2 exp10 kHz uncertaintywith slow-MumeasurementPrecise measurementof muon mass

Low-emittance muonsource via 1S-2S ionization(g-2 exp., Mu BEC etc.)

Low-TempSlow-muonium

R&D

Develop 244nmpulse laser system

Test exp. with HFY 2019 FY 2020 FY2021 FY2022~

Phase 0 experimentDetection system testby pulsed laser ionizationof Muonium

Phase 1 exp.Laser spectroscopyby narrow-linewidthlaser1 MHz uncertainty

High-powerpulse laser

High-powerCW laser

RAL 1999Phase 1(2 years)

Phase 2(5 years)

µ+ intensity 1.8x105 cps 6x106 cps

(S line)1x108 cps

(H line)

Mu yield 6x102 cps 6x104 cps 1x106 cps

Laser Pulsed CW 10W CW 40W

Exp. Linewidth 20 MHz ~10 MHz ~0.5 MHz

Stat. uncertainty 9.1 MHz

Simulation Study of 1S-2S ExcitationExpected resonance curves are calculated in three steps: Surface muon beam distribution (by G4beamline) Mu generation and tracking in thermal diffusion model by MC 1S-2S excitation is described by optical-Bloch equation

Excitation probability is obtained by solving optical-Bloch equation for each muonium diffused from silica aerogel

Visit Poster PN-06 by C. Zhang MLFPN-10 by T. Masuda

Develop whole detection system usinghydrogen spectroscopy apparatus

Test Experiment with Hydrogen

resonant 2-photonionization signal

Hydrogen

243 nm

243 nm

Muonium

244 nm

244 nm

[H generation]2.45 GHz Microwavedischarge

Discharge ON

Discharge OFF

Introduction to Okayama University Group Brief introduction of the SPAN project Macro-coherent amplificationFundamental Physics using Hydrogen-like atoms History and present of Hydrogen spectroscopy Muonium spectroscopy and New physics1S-2S Laser Spectroscopy project at J-PARC Motivation and goal Project overview and time schedule Recent status: simulation study and hydrogen testFuture prospects High brightness muon source by 1S-2S ionization of Mu High power 244 nm laser systemSummary

Outline

High Brightness Muon Production

Present beam: target(e.g. μSR )

target

emittance~1000� mm∙mrad

Proton

π production

decay

Future application of the Phase 0 experiment (1S-2S ionization)

1S-2S Laserionization@244 nm

Alternative to the on-goingLyman-α ionization @122 nm

Silicaaerogel

SOA Lens

High brightnessmuon beam

Difficultto focus

>20 mm

Conventional technique

Collaborating with M. Yoshida (KEK)

Conventional technique

Developing forphase 0 exp.

New!High-Power 244 nm Laser Source

Ti:Scrystal

Pump

CW laser SOA

arb. form pulse~30mW976 nm ~30mW×1μs→30 nJ

~600 mJpulse

x N stageamplifier

SHG400mJ

@488nm

FHG200mJ

@244nm

Similar Yb:YAG multi-pass amplifier system developed at KEK

Developing 244 nm high power laser is much easier than developing Lyman-α

Conventional technique can be usedEasy handling (air is transparent at 244 nm, while Lyman-α is strongly absorbed)

Similar ionization fraction→may become a good

alternative of Lyman-α

1S-2S Laser Ionization of Muonium

Wavelength PowerIonization

fraction81,946 Mu tot.

Lyman-α 122 nm (VUV) 3 μJ 3.0%

1S-2S REMPI 244 nm 200 mJ 1.6%

1S-2S ionization →

↑ Lyman-α ionization

The goal of this project:Realize the highest precision by use of state-of-the-art technologies developed in AMO physics (Ultrafine laser spectroscopy) Particle/Nuclear physics (High intensity accelerator)

1S-2S Laserspectroscopy

Accelerator technologies

Muon g-2

MuSEUM

Precision test of electroweak theory and search for new physics beyond the Standard Model

by laser spectroscopy of purely leptonic atoms

Precision EW test

JSPS KAKENHI Grant-in-Aid for Scientific Research (S) [FY2019-2023]

interdisciplinaryresearch project

High power laserLaser ionizationMu production