Äîęķėåíō âį˙ō čį ęũøā īîčņęîâîé ėāøčíû. Āäđåņ îđčãčíāëüíîãî äîęķėåíōā : http://www.gao.spb.ru/russian/psas/ffk2013/tfiles/Horvath_Asacusa_ffk2013.pdf Äāōā čįėåíåíč˙: Mon Nov 25 12:35:09 2013 Äāōā číäåęņčđîâāíč˙: Fri Feb 28 03:19:42 2014 Ęîäčđîâęā: Īîčņęîâûå ņëîâā: storm

ASACUSA: Measuring the Antiproton Mass and Magnetic Moment
Dezso HorvĀth on behalf of the ASACUSA Collaboration

horvath.dezso@wigner.mta.hu
Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary & Atomki, Debrecen, Hungary

Dezso HorvĀth

ASACUSA

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Outline
CPT Invariance and its Tests The Antiproton Decelerator at CERN The Charge and Mass of the Antiproton The Magnetic Moment of the Antiproton Outlook: ELENA
R.S. Hayano et al.: Antiprotonic helium and C P T invariance, Reports on Progress in Physics, 70 (2007) 1995-2065. M. Hori et al.: Two-photon laser spectroscopy of pbar-He+ and the antiproton-to-electron mass ratio, Nature 475 (2011) 484-488; Few Body Systems 54 (2013) 917-922 S. Friedreich et al.: Microwave spectroscopic study of the hyperfine structure of antiprotonic helium-3, arXive:1303.2831, 2013.

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CPT Invariance
Charge conjugation: C |p(r, t)> = |p(r, t)> Space reflection: P |p(r, t)> = |p(-r, t)> Time reversal: T |p(r, t)> = |p(r, -t)> Basic assumption of field theory: C P T |p(r, t)> = |p(-r, -t)> |p(r, t)> meaning free antipar ticle par ticle going backwards in space and time. Giving up C P T one has to give up: locality of interactions causality, or unitarity conservation of matter, information, ... or Lorentz invariance
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p e-

k



p-k

e

+

p'

k'




CPT Invariance: violation?
Field theorists in general: C P T cannot be violated!
C P T -violating theories: (Alan KosteleckŲ, F.R. Klinkhamer, N.E. Mavromatos et al)

Standard Model valid up to Planck scale ( 10 Above Planck scale new physics Lorentz violation possible

19

GeV).

Quantum gravity: fluctuations Lorentz violation Loss of information in black holes unitarity violation Motivation for testing C P T at low energy Quantitative expression of Lorentz and C P T invariance needs violating theory Low-energy tests can limit possible high energy violation
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How to test C P T ?
Par ticle = ­ antipar ticle ?
[m(K ) - m(K )]/m(average) < 10
0 0 -1 8

proton antiproton? (compare m, q , ĩ) hydrogen antihydrogen? (2S - 1S , HFS)

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Accelerators at CERN
1989­2000 2009­2025??

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ASACUSA

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The Antiproton Decelerator at CERN
has been built to test CPT invariance
Three experiments test CPT: ATRAP: q (p)/m(p) q (p)/m(p) H(2S - 1S ) H(2S - 1S ) ALPHA: H(2S - 1S ) H(2S - 1S ) ASACUSA: q (p)2 m(p) q (p)2 m(p) ĩ (p) ĩ (p) H H HF structure RED: done, GREEN: planned
c Ryugo S. Hayano

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ASACUSA

9 October 2013, St. Petersburg, Russia

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The Antiproton Decelerator: cooling
Momentum p[GeV/c] 3.57

Stochastic cooling 6.6 s. 2.0 pbar injection Bunch rotation Stochastic cooling 17 s.

Electron cooling 16s.

Electron cooling 8 s. Rebunching Fast Extraction

0.3 0.1 RF ON: 12 35 54 71 85 time [s]

4 â 107 100 MeV/c antiprotons ever y 85 s
Pavel Belochitskii: AIP Conf. Proc. 821 (2006) 48
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Mass and Charge of Antiproton
Proton's well (?) known: m ( p) / m ( e ) = 1 8 3 6 . 1 5 2 6 7 2 4 5 ( 7 5 ) q ( e) = 1 . 6 0 2 1 7 6 5 6 5 ( 3 5 ) â 1 0 - 1 9 C Precision: 4 ˇ 10-10 and 2 ˇ 10-8 Relative measurements: proton vs. antiproton Cyclotron frequency in trap q /m TRAP ATRAP collaboration
Harvard, Bonn, MŨnchen, Seoul Atomic Spectroscopy And Collisions Using Slow Antiprotons

p and H- together 10

-1 0

precision

Atomic transitions: E n - m re d c 2 ( Z ) 2 / ( 2 n ) m ˇ q 2 PS-205 ASACUSA collaboration
Tokyo, Brescia, Budapest, Debrecen, Munich, Vienna
Asakusa, Tokyo

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ASACUSA

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Metastable hadronic atoms
In matter (gas, liquid, solid) (hadron) 1 ps except 3% of X- He: K- , - : decay lifetime; p: 3­4 ĩs

Metastable 3-body system Auger suppressed, slow radiative transitions only Electron cloud protects p against collisions Electron tightly bound: 1S pHe: n 40, l n - 1, Rydberg state
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p-He : spectroscopy motivation
Vladimir Korobov calculates p transition frequencies in p-He+ with the precision of 10-9 Determination of antiproton-to-electron mass ratio to 1 . 3 â 1 0 -9 . - Dimensionless fundamental constant of nature. Determination of electron mass in a.u. to 1.3 â 10-9 - One of the data points for CODATA2010 average. When combined with cyclotron frequency of antiprotons in a Penning trap measured by the TRAP collaboration, comparison of antiproton and proton mass and charge to 7 â 10-10 - CPT consistency test in PDG2012.

+

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Energy levels of pHe

4

Level energies in eV, transition wavelengths in nm
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Induce transition between long-lived and shor t-lived states Force prompt annihilation
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ASACUSA: Spectroscopy setup

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Laser spectroscopy of antiprotonic helium

N. Morita et al, Phys. Rev. Lett. 72 (1994) 1180­1183.
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Laser spectroscopy: LEAR vs AD
4000 3500 3000 2500 2000 1500 1000 500 0 0 -2.5 -5 -7.5 -10 -12.5 -15 -17.5 -20 0 0.5 1 counts / 10 ns

event-by-event

= 470.724 nm

LEAR: slow extraction 10 6 laser shots, 50 min
4

0

0.5

1

analog amplitude (arb. units)

1.5 2 2.5 3 Annihilation time (ĩs)

3.5

analog method = 470.724 nm

AD: fast extraction 1 laser shot, 2 min
3.5 4

1.5 2 2.5 3 Annihilation time (ĩs)

Gated phototube: prompt annihilation (97% p) off (Hamamatsu)
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Transition frequencies in isolated pHe+ atoms
Exp. precision limited by: collisions, Doppler broadening, laser bandwidth 1996-2002: measured density dependence, extrapolated to zero 2003-2004: reduced collisional effects by stopping slow p from RFQ post-decelerator in low-pressure (< 1 mbar), cr yogenic target 2005-2007: reduce laser bandwidth using frequency comb 2008: star t 2-photon spectroscopy Last published CPT-violation limit by 1-photon spectroscopy: 2 ppb (2 â 10-9 ) at CL 90%.
M. Hori et al., Phys. Rev. Lett. 96 (2006) 243401.
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M. Hori et al., Phys. Rev. Lett. 87 (2001) 093401.


Radiofrequency quadrupole decelerator
y z x 0

5 cm

Focussing-defocussing in alternate planes U 170 kV; f 202 MHz; bias ą55 kV 5,3 MeV 65 keV: efficiency 30%
RF buncher energy corrector Solenoid magnets Cherenkov detectors

p

RFQD Dipole magnets Quadrupole magnets Quadrupole triplet Laser

Cryogenic helium target
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Resolution and stability
2000 2002 2004 2010

Dramatic improvement of resolution and stability Resonance profile of the (n, ) = (37, 35)(38, 34) transition at = 726.1 nm 2010: He at T = 1.5K , Ti:Sapphire pulsed laser
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Determination of m(p), q (p)
8

TRAP Antiprotonic Helium

6 4 2
8

6 4 2 2 4 6 -6 -4 -2 -2 -4 -6 2 4 6

-6

-4

-2 -2 -4 -6

Determination of antiproton mass and charge: possible deviation from those of the proton TRAP: m/Q;
Dezso HorvĀth ASACUSA

ASACUSA: m ˇ Q

2
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Two-photon spectroscopy
In low density gas main precision limitation: thermal Doppler broadening even at T < 10 K Excite = 2 transition with 2 photons Two counterpropagating photons with 1 eliminate 1st order Doppler effect
2

Laser linewidth should not overlap with resonance
M. Hori, A. SŅtČr, D. Barna, A. Dax, R.S. Hayano, S. Friedreich, B. JuhĀsz, T. Pask, E. Widmann, D. Hor vĀth, L. Venturelli, N. Zurlo: Two-photon laser spectroscopy of pbar-He+ and the antiproton-to-electron mass ratio, Nature 475 (2011) 484-488, Few Body Syst. 54 (2013) 917-922.

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1-photon vs 2-photon spectroscopy
417 nm 372 nm

(36,34)

417 nm

Virtual state E (35,33) 372 nm

(34,32)

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Near-resonant two-photon spectroscopy
(n, ) = (36, 34)(34, 32)
417 nm 372 nm

Doppler suppression:
1 - 2 = 1 + 2

(36,34)

417 nm



1

2

Doppler
Virtual state

Gain: 20â Limitation: residual Doppler, frequency chirp systematics Expected f few MhZ
(34,32)
Dezso HorvĀth ASACUSA 9 October 2013, St. Petersburg, Russia

E (35,33) 372 nm

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Two-photon spectroscopy: setup

M. Hori et al., Nature 475 (2011) 484-488

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Two-photon spectroscopy: parameters
Precision of lasers: < 1.4 â 10-9 .
7 â 106 p/pulse, E 70 keV, 200 ns long, ü20 mm.

Target: He gas, T 15 K, p = 0.8 - 3 mbar Laser beams: 1 = 417 nm, 2 = 372 nm, P 1 mJ/cm2 Transition: (n=36, l=34) (n=34, l=32); = 6 GHz Measured linewidth: 200 MHz Width: Residual Doppler broadening, hyperfine structure, Auger lifetime, power broadening.
M. Hori, A. SŅtČr, D. Barna, A. Dax, R.S. Hayano, S. Friedreich, B. JuhĀsz, T. Pask, E. Widmann, D. Hor vĀth, L. Venturelli, N. Zurlo: ,,Two-photon laser spectroscopy of pbar-He+ and the antiproton-to-electron mass ratio" Nature 475 (2011) 484-488
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Two-photon spectroscopy: spectra

M. Hori et al., Nature 475 (2011) 484-488

Arrows: hyperfine transitions
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Two-photon spectroscopy: uncertainties
Source error (MHz) Statistics Collisional shift A.c. Stark shift Zeeman shift Frequency chir p Laser freq. cal. Hyperfine structure Line profile sim. Total systematic Total experimental Theor y
Dezso HorvĀth

3 1 0.5 <0.5 0.8 <0.1 <0.5 1 1.8 3.5 2.1
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Two-photon spectroscopy: results
Mp / m e = 1 8 3 6 . 1 5 2 6 7 3 6 ( 2 3 )

Uncer tainties: 1 . 8 â 1 0 - 6 ( st a t ) , 1 . 2 â 1 0 - 6 ( sy st ) , 1 . 0 â 1 0 - 6 ( t h eo r ) Good agreement with proton results, similar (slightly higher) uncer tainty. Assuming CPT invariance our result can be included in the determination of Mp and me . Using the TRAP limit for difference of Q/M for the proton and the antiproton and averaging our three values we can establish an upper limit for the charge and mass difference (i.e. possible CPT violation) at 7 â 1 0 -1 0 on a 90% confidence level.
M. Hori et al., Nature 475 (2011) 484-488
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Measuring the magnetic moment of p

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Level splitting in pHe atoms
F-'=L' -1/2 F-'=L' -1/2

+

(n',L')
F-=L-1/2 J =L J =L-1
-- -+

(n',L')
F-=L-1/2 J-+=L J =L-1
--

F-=L-1/2

J =L J =L-1
--

-+

F '=L'+1/2

+

(n,L)

(n,L) H
+ F

F '=L'+1/2

+

(n,L)

f+
F =L+1/2
+

J = L+1 F =L+1/2
+

++

HF

-

J++= L+1

f+
F =L+1/2
+

J = L+1

++

J+-=L

J =L

+-

J+-=L

Step 1: depopulation of F+ doublet with f+ laser pulse

Step 2: equalization Step 3: probing of population of populations of of F+ doublet with 2nd f+ F+ and F- by laser pulse microwave 1.15 - + HF HF
1.10

R++/R++off

Magnetic moments ĩ(p) ĩ(p) CPT invariance OK
E. Widmann, R.S. Hayano, T. Ishikawa, J. Sakaguchi, H. Yamaguchi, J. Eades, M. Hori, H.A. Torii, B. JuhĀsz, D. Hor vĀth, T. Yamazaki: Phys. Rev. Lett. 89 (2002) 243402.

1.05

1.00

0.95 12.86 12.88 12.90 12.92 12.94 12.96



MW

(GHz)

Microwave frequency scan
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p He HF structure: expt vs. theory

4

Th. Pask et al., Phys. Lett. B 678 (2009) 55.

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p He HF structure: laser scan

3

S. Friedreich et al., Physics Letters B 700 (2011) 1.
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p He HF structure: microwave scan

3

S. Friedreich et al., Physics Letters B 700 (2011) 1.
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S. Friedreich et al. arXive:1303.2831, 2013.
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Plans, future prospects
Colder atoms (T = 1.6 K), better lasers, better detectors (segmented scints) Use more transitions, collect more statistics ELENA (colder antiproton beams at 100 keV of higher luminosity) Spectroscopy on Hbeam

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MUSASHI: slow p and H beam
Monoenergetic Ultra Slow Antiproton Source for High­precision Investigations
Musashi Miyamoto self-por trait 1640

5.8 MeV p injected into RFQ 100 keV p injected into trap 106 p trapped and cooled (2002) 350000 slow p extracted (2004) Cold p compressed in trap (2008) (5 â 105 p, E = 0.3 eV, R = 0.25 mm) H-beam formed for in-flight spectroscopy: 2010-2012
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Spectroscopy with H beam
anti proton and positr on Trap / Recombination p + e

Sextupole I

Microwave Cavity

Sextupole II

Anti hydrogen Dete ctor

H spectr in flight: polariser, resonator, analyser Analogy: polarised light
R.S. Hayano et al., Rep. Progr. Phys. 70 (2007) 1995. E. Widmann et al., progress repor ts in conf. papers
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Extra Low ENergy Antiprotons
Success of RFQ post-decelerator of ASACUSA CERN decided to build storage ring ELENA.

Plan: launch it in 2016. AD: 5.8 MeV p, 3 â 107 /shot ELENA: 100 keV p, 1.8 â 107 /shot 4 bunches to 4 expts every 120 sec DĀniel Barna: Design of beam line
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Segmented detectors for Paul trap

A. SŅtČr, K. Todoroki, T. Kobayashi, D. Barna, D. Hor vĀth, M. Hori: Submitted to Nucl. Instr. Meth
Dezso HorvĀth ASACUSA

Trap design: D. Barna, M. Hori
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Conclusion
The first sub-Doppler two-photon spectroscopy of antiprotonic helium: two transitions in 4 He and one in 3 He. Results agree with 3-body QED calculations. Determined Mp /me ratio to 1.3 ppb. Result agrees with CODATA proton value (0.4 ppb). Fur ther improvement par tially hindered by theoretical uncer tainty (QED terms < 6 , radiative recoil corrections) Big improvement expected from ELENA in 2016.

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Thanks for your attention

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ASACUSA

9 October 2013, St. Petersburg, Russia

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