News from the Proton Radius Puzzle muonic deuterium

Size: px

Start display at page:

Download "News from the Proton Radius Puzzle muonic deuterium"

Reynold Crawford
5 years ago
Views:

1 News from the Proton Radius Puzzle muonic deuterium Muonic news Muonic hydrogen and deuterium Randolf Pohl Randolf Pohl Max-Planck-Institut für Quantenoptik Garching, Germany 1

2 Outline The problem: Proton rms charge radius r p from muonic hydrogen µp is 4 % smaller than the values from elastic electron-proton scattering and hydrogen spectroscopy. That s 5σ... 8σ. But the µp result is 10 times more accurate than any other measurement. Introduction Muonic hydrogen Muonic deuterium Muonic helium Muonic future Randolf Pohl Mainz, 2 nd June

3 Muonic measurements. Randolf Pohl Mainz, 2 nd June

4 Setup Randolf Pohl Mainz, 2 nd June

5 Muon beam line Randolf Pohl Mainz, 2 nd June

6 The laser system 200 W Yb:YAG thin disk laser 500 W 43 mj µ Oscillator 1030 nm Oscillator 1030 nm 200 W 9 mj 9 mj Amplifier SHG Amplifier 500 W 43 mj SHG 23 mj 515 nm 23 mj 1.5 mj 6 µ m monitoring TiSa Amp. 20 m H O Ge filter SHG 6 m 2 µ 0.25 mj 6 µ m cavity cw TiSa laser Wave meter FP I / Cs 2 7 mj Raman cell Verdi 5 W cw TiSa 708 nm 400 mw TiSa Osc. 708 nm, 15 mj Main components: Thin-disk laser fast response to detected µ Frequency doubling TiSa laser: frequency stabilized cw laser injection seeded oscillator multipass amplifier Raman cell 3 Stokes: 708 nm 6 µm λ calibration (1) wavemeter + known Raman shift (2) H 2 O spectr. at 6 µm Target cavity A. Antognini, RP et. al., Opt. Comm. 253, 362 (2005) Randolf Pohl Mainz, 2 nd June

7 Atomic physics Wave functions of S and P states: 8S... 4S 3S 3D 2S 2P S states: max. at r=0 Electron sometimes inside the proton. S states are shifted. P states: zero at r=0 Electron is not inside the proton. Shift ist proportional to the size of the proton 1S Orbital pictures from Wikipedia Randolf Pohl Mainz, 2 nd June

8 Atomic physics arb. units 8S... 4S 3S 3D Coulomb potential: V = 1/r 2S 2P radius [fm] S states: max. at r=0 Electron sometimes inside the proton. S states are shifted. Shift ist proportional to the size of the proton 1S P states: zero at r=0 Electron is not inside the proton. Orbital pictures from Wikipedia Randolf Pohl Mainz, 2 nd June

9 Atomic and nuclear physics arb. units proton charge 8S... 4S 3S 3D Coulomb potential: V = 1/r 2S 2P radius [fm] S states: max. at r=0 Electron sometimes inside the proton. S states are shifted. Shift ist proportional to the size of the proton 1S P states: zero at r=0 Electron is not inside the proton. Orbital pictures from Wikipedia Randolf Pohl Mainz, 2 nd June

5 1 1.5 2 2.5 radius [fm] S states: max.

P states: zero at r=0 Electron is not inside the proton.

10 Atomic and nuclear physics arb. units proton charge 8S... 4S 3S 3D true potential Coulomb potential: V = 1/r 2S 2P radius [fm] S states: max. at r=0 Electron sometimes inside the proton. S states are shifted. P states: zero at r=0 Electron is not inside the proton. Shift ist proportional to the size of the proton 1S Orbital pictures from Wikipedia Randolf Pohl Mainz, 2 nd June

11 Proton charge radius and muonic hydrogen Lamb shift in µp [mev]: E = (25) (10)r 2 p Proton size effect is 2% of the µ p Lamb shift µp(n=2) levels: 2P 3/2 2P 1/2 206 mev 50 THz 6 µm 8.4 mev F=2 F=1 F=1 F=0 Measure to 10 5 r p to 0.05 % 225 mev 55 THz 5.5 µm Experiment: R. Pohl et al., Nature 466, 213 (2010). A. Antognini, RP et al., Science 339, 417 (2013). Theory summary: A. Antognini, RP et al., Ann. Phys. 331, 127 (2013). fin. size: 3.7 mev 2S 1/2 F=1 23 mev F=0 Randolf Pohl Mainz, 2 nd June

12 The resonance: discrepancy, sys., stat. Water-line/laser wavelength: ν water-line to resonance: 300 MHz uncertainty 200 khz uncertainty ] 7 CODATA-06 our value delayed / prompt events [ e-p scattering H 2 O calib. Statistics: 700 MHz Systematics: 300 MHz laser frequency [THz] Discrepancy: 5.0σ 75 GHz δν/ν = R. Pohl et al., Nature 466, 213 (2010). A. Antognini, RP et al.,science 339, 417 (2013). Randolf Pohl Mainz, 2 nd June

13 The proton radius puzzle. Randolf Pohl Mainz, 2 nd June

14 The proton radius puzzle The proton rms charge radius measured with electrons: muons: ± fm ± fm 7.9 σ µ p 2013 electron avg. scatt. JLab µp 2010 scatt. Mainz H spectroscopy R. Pohl et al., Nature 466, 213 (2010). A. Antognini et al., Science 339, 417 (2013). Proton charge radius R ch Randolf Pohl Mainz, 2 nd June [fm]

15 The proton radius puzzle The proton rms charge radius measured with electrons: muons: ± fm ± fm 7.9 σ µ p 2013 electron avg. dispersion 2012 µp 2010 dispersion 2007 scatt. JLab scatt. Mainz H spectroscopy Belushkin, Hammer, Meissner PRC 75, (2007). Lorenz, Hammer, Meissner EPJ A 48, 151 (2012). Proton charge radius R ch Randolf Pohl Mainz, 2 nd June [fm]

16 The proton radius puzzle The proton rms charge radius measured with electrons: muons: ± fm ± fm 7.9 σ µ p 2013 electron avg. scatt. JLab µp 2010 scatt. Mainz H spectroscopy Proton charge radius R [fm] ch RP, Gilman, Miller, Pachucki, Annu. Rev. Nucl. Part. Sci. 63, 175 (2013). Randolf Pohl Mainz, 2 nd June

The proton radius puzzle The proton rms charge radius measured with electrons: 0.8770 ± 0.0045 fm muons: 0.8409 ± 0.0004 fm 7.9 σ µ p 2013 electron avg.

17 The proton radius puzzle The proton rms charge radius measured with electrons: ± fm muons: ± fm 7.9 σ µ p 2013 electron avg. scatt. JLab µp 2010 scatt. Mainz H spectroscopy Proton charge radius R [fm] ch Randolf Pohl Mainz, 2 nd June

18 Muons in the news Randolf Pohl Mainz, 2 nd June

19 Muons in the news Randolf Pohl Mainz, 2 nd June

20 Muons in the news Randolf Pohl Mainz, 2 nd June

21 Muons in the news J. Bernauer, RP Randolf Pohl Mainz, 2 nd June

22 Muons in the news J. Bernauer, RP Randolf Pohl Mainz, 2 nd June

ECT* Workshop The Proton Radius Puzzle, Trento, Italy, Oct. 28 - Nov. 2, 2012 G.A. Miller, R.

23 ECT* Workshop The Proton Radius Puzzle, Trento, Italy, Oct Nov. 2, 2012 G.A. Miller, R. Gilman, RP 47 theorists + experimentalists atomic physics electron scattering nuclear physics Beyond SM 38 talks 3 fighting sessions no solution voting: more data needed RP, R. Gilman, G.A. Miller, K. Pachucki, Muonic hydrogen and the proton radius puzzle, Annu. Rev. Nucl. Part. Sci. 63, 175 (2013) (arxiv ) Randolf Pohl Mainz, 2 nd June

24 What may be wrong? L theo. µ p (rp CODATA µp theory wrong? ) L exp. µ p = 75 GHz 0.31 mev 0.15 % µp experiment wrong? H theory wrong? H experiments wrong? R wrong? AND e-p scattering exp. wrong? Standard Model wrong?!? RP, R. Gilman, G.A. Miller, K. Pachucki, Muonic hydrogen and the proton radius puzzle, Annu. Rev. Nucl. Part. Sci. 63, 175 (2013) (arxiv ) Randolf Pohl Mainz, 2 nd June

25 What may be wrong? L theo. µ p (rp CODATA ) L exp. µ p = 75 GHz 0.31 mev 0.15 % µp theory wrong? New measurements: µp experiment wrong? H Muonic theory wrong? hydrogen, deuterium, helium ions H Hydrogen experiments spectroscopy wrong? R Rydberg wrong? constant, r p AND e-p scattering exp. wrong? Helium ion Rydberg constant, QED test Theory: Elastic electron scattering at lower Q 2, p, d, He Standard Model wrong?!? Muon scattering: PSI QED in electronic and muonic atoms Nucl. structure effects: p, d, 3,4 He,... Electron scattering Lattice... RP, R. Gilman, G.A. Miller, K. Pachucki, Muonic hydrogen and the proton radius puzzle, Annu. Rev. Nucl. Part. Sci. 63, 175 (2013) (arxiv ) Randolf Pohl Mainz, 2 nd June

26 Muonic hydrogen Randolf Pohl Mainz, 2 nd June

27 We have measured two transitions in µp 2P fine structure ν t = ν(2s F=1 1/2 2PF=2 3/2 ) 2P 3/2 2P 1/2 F=2 F=1 F=1 F=0 ν triplet Lamb shift ν singlet ν s = ν(2s F=0 1/2 2PF=1 3/2 ) F=1 2S 1/2 2S hyperfine splitting F=0

28 We have measured two transitions in µp 2P fine structure Consider the two measurements separately 2P 3/2 2P 1/2 F=2 F=1 F=1 F=0 Two independent determinations of r p (ν t r p, ν s r p ) Consistent results! ν triplet Lamb shift ν singlet F=1 2S 1/2 2S hyperfine splitting F=0

29 We have measured two transitions in µp 2P fine structure Consider the two measurements separately 2P 3/2 2P 1/2 F=2 F=1 F=1 F=0 Two independent determinations of r p (ν t r p, ν s r p ) Consistent results! ν triplet Lamb shift ν singlet Combine the two measurements Two measurements determine two parameters ν t,ν s E L, E HFS r p, r Z! F=1 2S 1/2 F=0 2S hyperfine splitting 3 4 ν t+ 4 1ν s = E L (r p ) mev ν s ν t = E HFS (r Z ) mev

30 Proton charge radius ν(2s F=1 ν(2s F=0 1/2 2PF=2 3/2 1/2 2PF=1 3/2 ) = (76) GHz R. Pohl et al., Nature 466, 213 (2010) (65) GHz ) = (1.05) GHz } A. Antognini, RP et al., Science 339, 417 (2013) Proton charge radius: r p = (26) exp (29) th = (39) fm µp theory summary: A. Antognini, RP et al., Ann. Phys. 331, 127 (2013) [arxiv : (atom-ph)] µp 2013 e-p, JLab dispersion 2012 CODATA-2010 µp 2010 dispersion 2007 e-p, Mainz H/D Proton charge radius R ch [fm] Randolf Pohl Mainz, 2 nd June

31 Proton Zemach radius 2S hyperfine splitting in µp is: E HFS = (30) (10)r Z [fm] mev with r Z = d 3 r d 3 r r ρ E (r)ρ M (r r ) We measured E HFS = (51) mev This gives a proton Zemach radius r Z = (31) exp (20) th = (37) fm µp 2013 e-p, Mainz H, Volotk a e-p, Friar H, Dupays Proton Zemach radius R Z [fm] A. Antognini, RP et al., Science 339, 417 (2013) Randolf Pohl Mainz, 2 nd June

32 Rydberg constant fractional uncertainty single measurements least-square adjustments muonic hydrogen + H(1S-2S) year H(1S-2S): C.G. Parthey, RP et al., PRL 107, (2011). r p : A. Antognini, RP et al., Science 339, 417 (2013). Randolf Pohl Mainz, 2 nd June

33 Rydberg constant Hydrogen spectroscopy (Lamb shift): fractional uncertainty S 4S 3S 10 2S L 1S (r p )= (4) r 2 p MHz S-2S 2P 3D E ns R n 2 + L 1S single measurements n 3 least-square adjustments muonic hydrogen + H(1S-2S) 2 unknowns 2 transitions Rydberg constant R S Lamb shift L 1S r p year H(1S-2S): C.G. Parthey, RP et al., PRL 107, (2011). r p : A. Antognini, RP et al., Science 339, 417 (2013). Randolf Pohl Mainz, 2 nd June

34 Rydberg constant R = (10) r p (25) QED Hz/c [8 parts in ] fractional uncertainty single measurements least-square adjustments muonic hydrogen + H(1S-2S) year H(1S-2S): C.G. Parthey, RP et al., PRL 107, (2011). r p : A. Antognini, RP et al., Science 339, 417 (2013). Randolf Pohl Mainz, 2 nd June

35 Deuteron charge radius H/D isotope shift: r 2 d r2 p = (65) fm 2 C.G. Parthey, RP et al., PRL 104, (2010) CODATA 2010 r d = (21) fm CODATA-2010 CODATA D + e-d e-d scatt. n-p scatt Deuteron charge radius [fm] Randolf Pohl Mainz, 2 nd June

36 Deuteron charge radius H/D isotope shift: r 2 d r2 p = (65) fm 2 C.G. Parthey, RP et al., PRL 104, (2010) CODATA 2010 r p = (39) fm from µh gives r d = (21) fm r d = (22) fm µh + iso H/D(1S-2S) CODATA-2010 CODATA D + e-d e-d scatt. n-p scatt Deuteron charge radius [fm] Randolf Pohl Mainz, 2 nd June

37 Deuteron charge radius H/D isotope shift: r 2 d r2 p = (65) fm 2 C.G. Parthey, RP et al., PRL 104, (2010) CODATA 2010 r p = (39) fm from µh gives Lamb shift in muonic DEUTERIUM r d = (21) fm r d = (22) fm????????????? µh + iso H/D(1S-2S) CODATA-2010 CODATA D + e-d e-d scatt. n-p scatt Deuteron charge radius [fm] Randolf Pohl Mainz, 2 nd June

38 Muonic deuterium Randolf Pohl Mainz, 2 nd June

39 muonic deuterium 2P 2P 3/2 1/2 2S 1/2 F=3/2 F=1/2 Randolf Pohl Mainz, 2 nd June

40 muonic deuterium 2P 2P 3/2 1/2 2P 3/2 F=5/2 F=1/2 F=3/2 2P 1/2 F=3/2 F=1/2 F=3/2 2S 1/2 2S 1/2 F=3/2 F=1/2 F=1/2 Randolf Pohl Mainz, 2 nd June

41 Muonic DEUTERIUM ] resonances in muonic deuterium delayed / prompt events [ µd [ 2S 1/2 (F=3/2) 2P 3/2 (F=5/2) ] 20 ppm (stat., online) µd [ 2S 1/2 (F=1/2) 2P 3/2 (F=3/2) ] 45 ppm (stat., online) ] -4 delayed / prompt events [ ν THz (GHz) µd [ 2S 1/2 (F=1/2) 2P 3/2 (F=1/2) ] 70 ppm (stat., online) only 5σ significant identifies F=3/2 line 2S 1/2 2P 3/2 2P 1/2 F=3/2 F=5/2 F=1/2 F=3/2 F=3/2 F=1/ ν THz (GHz) Randolf Pohl Mainz, 2 nd June F=1/2

42 Deuteron charge radius H/D isotope shift: r 2 d r2 p = (65) fm 2 C.G. Parthey, RP et al., PRL 104, (2010) CODATA 2010 r p = (39) fm from µh gives r d = (21) fm r d = ( 2) fm µh + iso H/D(1S-2S) CODATA-2010 CODATA D + e-d e-d scatt. n-p scatt Deuteron charge radius [fm] Randolf Pohl Mainz, 2 nd June

43 Deuteron charge radius H/D isotope shift: r 2 d r2 p = (65) fm 2 C.G. Parthey, RP et al., PRL 104, (2010) CODATA 2010 r p = (39) fm from µh gives r d = (21) fm r d = ( 2) fm Lamb shift in muonic DEUTERIUM r d = (12) fm PRELIMINARY! µd Borie+Pachucki+Ji+Friar µd Borie+Ji µd Borie+Pachucki µd Martynenko µh + iso H/D(1S-2S) CODATA D + e-d e-d scatt. n-p scatt. PRELIMINARY CODATA Deuteron charge radius [fm] Randolf Pohl Mainz, 2 nd June

44 Deuteron charge radius µh and µd are consistent! (if BSM: no coupling to neutrons) WIP: deuteron polarizability (theory) complete? double-counting? WIP: shift from QM-interference µd Borie+Pachucki+Ji+Friar µd Borie+Ji µd Borie+Pachucki µd Martynenko µh + iso H/D(1S-2S) PRELIMINARY CODATA-2010 CODATA D + e-d e-d scatt. n-p scatt Deuteron charge radius [fm] Randolf Pohl Mainz, 2 nd June

45 Proton-deuteron isotope shift In other words: The muonic isotope shift agrees with the electronic one! rd 2 r2 p : H/D isotope shift ± fm2 muonic Lamb shift ± fm 2 PRELIMINARY! scattering ± fm 2 The muonic error is conservative (nucl. structure terms). PRELIMINARY µd/µp (2S-2P) scattering electronic H/D (1S-2S) R d 2 - R p 2 [fm ] Randolf Pohl Mainz, 2 nd June

46 Muonic helium. Randolf Pohl Mainz, 2 nd June

47 Lamb shift in muonic helium CREMA collaboration: Charge Radius Experiment with Muonic Atoms Goal: Measure E(2S-2P) in µ 4 He, µ 3 He alpha particle and helion charge radius to (± fm) Randolf Pohl Mainz, 2 nd June

48 Lamb shift in muonic helium CREMA collaboration: Charge Radius Experiment with Muonic Atoms Goal: Measure E(2S-2P) in µ 4 He, µ 3 He alpha particle and helion charge radius to (± fm) 2P 3/2 2P 1/2 206 mev 50 THz 6 µm 8.4 mev F=2 F=1 F=1 F=0 2P 146 mev µp µ 4 He µ 3 He 812 nm 898 nm 2P 3/2 2P 1/2 2P 2P 3/2 2P 1/2 145 mev F=1 F=2 F=0 F=1 fin. size: 3.8 mev 2S 1/2 F=1 23 mev F=0 2S 1/2 fin. size effect 290 mev 2S 1/2 F=0 F=1 167 mev fin. size effect 397 mev Randolf Pohl Mainz, 2 nd June

49 Lamb shift in muonic helium CREMA collaboration: Charge Radius Experiment with Muonic Atoms Goal: Measure E(2S-2P) in µ 4 He, µ 3 He alpha particle and helion charge radius to (± fm) aims: help to solve the proton size puzzle absolute charge radii of helion, alpha low-energy effective nuclear models: 1 H, 2 D, 3 He, 4 He QED test with He + (1S-2S) MPQ, Amsterdam] Randolf Pohl Mainz, 2 nd June

Lamb shift in muonic helium CREMA collaboration: Charge Radius Experiment with Muonic Atoms Goal: Measure E(2S-2P) in µ 4 He, µ 3 He alpha particle and helion charge radius to 3 10 4 (± 0.

50 Lamb shift in muonic helium CREMA collaboration: Charge Radius Experiment with Muonic Atoms Goal: Measure E(2S-2P) in µ 4 He, µ 3 He alpha particle and helion charge radius to (± fm) aims: help to solve the proton size puzzle absolute charge radii of helion, alpha low-energy effective nuclear models: 1 H, 2 D, 3 He, 4 He QED test with He + (1S-2S) MPQ, Amsterdam] 4 He beam time: Oct.-Dec He beam time: May-Aug Talk by Aldo Antognini, tomorrow morning! Randolf Pohl Mainz, 2 nd June

51 Future muonic experiments Z=1: Muonic hydrogen: HFS Muonic deuterium: Lamb shift, HFS Muonic tritium Lamb shift: absolute charge radius 2S-HFS: Z=2: Muonic 4 He: Fine structure Muonic 3 He: Lamb shift, fine and hyperfine structure Z=3, 4, 5: nuclear polarizability Zemach / magnetic radius nuclear polarizability Randolf Pohl Mainz, 2 nd June

Future muonic experiments Z=1: Muonic hydrogen: HFS Muonic deuterium: Lamb shift, HFS Muonic tritium Lamb shift: absolute charge radius 2S-HFS: Z=2: Muonic 4 He: Fine structure Muonic 3 He:

52 Future muonic experiments Z=1: Muonic hydrogen: HFS Muonic deuterium: Lamb shift, HFS Muonic tritium Lamb shift: absolute charge radius 2S-HFS: Z=2: Muonic 4 He: Fine structure Muonic 3 He: Lamb shift, fine and hyperfine structure Z=3, 4, 5: nuclear polarizability Zemach / magnetic radius nuclear polarizability Drake, Byer, PRA 32, 713 (1985) Randolf Pohl Mainz, 2 nd June

53 Future muonic experiments Z=1: Muonic hydrogen: HFS Muonic deuterium: Lamb shift, HFS Muonic tritium Lamb shift: absolute charge radius 2S-HFS: Z=2: Muonic 4 He: Fine structure Muonic 3 He: Lamb shift, fine and hyperfine structure nuclear polarizability Zemach / magnetic radius nuclear polarizability Z=3, 4, 5: (Electronic) isotope shifts have been measured very accurately. (squared) charge radius differences are very well known. Muonic Lamb shifts provide absolute charge radii. Test of few-electron (QED) calculations. Ab initio nuclear structure calculations. Also: 1S-2S in (electronic) tritium. Missing link at A=3 Randolf Pohl Mainz, 2 nd June

54 Summary Muonic hydrogen gives: Proton charge radius: r p = (39) fm Proton Zemach radius: R Z = (37) fm Rydberg constant: R = (10) radius (25) QED Hz/c Deuteron charge radius: r d = (22) fm from µh + H/D(1S-2S) The Proton radius puzzle muonic deuterium: r d = (12) fm from µd (PRELIMINARY!) Lamb shift in mud is ok. 2S-HFS is missing a large (polarizability) term! Proton radius puzzle persists. New data needed! muonic helium hydrogen... Randolf Pohl Mainz, 2 nd June

55 Two muon puzzles Anomalous magnetic moment of the muon The measured value of a µ =(g 2)/2 of the muon has been in disagreement with the SM predictions for >10 years now! The discrepancy stands at 3.6σ J. Phys. G 38, (2011). Randolf Pohl Mainz, 2 nd June

56 Two muon puzzles Anomalous magnetic moment of the muon The measured value of a µ =(g 2)/2 of the muon has been in disagreement with the SM predictions for >10 years now! The discrepancy stands at 3.6σ Randolf Pohl Mainz, 2 nd June

57 Two muon puzzles Anomalous magnetic moment of the muon 3.6σ Proton radius from muonic hydrogen The measured value of the proton rms charge radius from muonic hydrogen µ p is 10 times more accurate, but 4% smaller than the value from both hydrogen spectroscopy and elastic electron proton scattering. 7.9 σ µ p 2013 electron avg. scatt. JLab µp 2010 scatt. Mainz H spectroscopy Proton charge radius R [fm] ch RP et al., Nature 466, 213 (2010); Science 339, 417 (2013); ARNPS 63, 175 (2013). Randolf Pohl Mainz, 2 nd June

58 Two muon puzzles Anomalous magnetic moment of the muon 3.6σ Proton radius from muonic hydrogen 7.9σ These 2 discrepancies may be connected. r p a µ Karshenboim, McKeen, Pospelov, arxiv Randolf Pohl Mainz, 2 nd June

59 r p and a µ Both the r p and the a µ discrepancy could originate from the same new proton structure effect (two-photonexchange) or New light Physics (m MeV) r p a µ Fixing r p could give rise to < (a µ ) <10 7 (for Λ had = m π... p p ). This is much larger than the (g 2) µ discrepancy of J. Phys. G 38, (2011). after Pospelov Karshenboim, McKeen, Pospelov, arxiv Randolf Pohl Mainz, 2 nd June

60 r p and a µ Both the r p and the a µ discrepancy could originate from the same new proton structure effect (two-photonexchange) or New light Physics (m MeV) r p a µ Fixing r p could give rise to < (a µ ) <10 7 (for Λ had = m π... p p ). This is much larger than the (g 2) µ discrepancy of J. Phys. G 38, (2011). June 22 July 25, 2013 after Pospelov Karshenboim, McKeen, Pospelov, arxiv Randolf Pohl Mainz, 2 nd June

(for Λ had = m π... p p ). This is much larger than the (g 2) µ discrepancy of 1 10 9. J. Phys.

61 r p and a µ Both the r p and the a µ discrepancy could originate from the same new proton structure effect (two-photonexchange) or New light Physics (m MeV) r p a µ Fixing r p could give rise to < (a µ ) <10 7 (for Λ had = m π... p p ). This is much larger than the (g 2) µ discrepancy of J. Phys. G 38, (2011). June 22 July 25, 2013 after Pospelov Karshenboim, McKeen, Pospelov, arxiv Randolf Pohl Mainz, 2 nd June

62 r p and a µ Both the r p and the a µ discrepancy could originate from the same new proton structure effect (two-photonexchange) or New light Physics (m MeV) r p a µ Fixing r p could give rise to < (a µ ) <10 7 (for Λ had = m π... p p ). This is much larger than the (g 2) µ discrepancy of J. Phys. G 38, (2011). Maybe one can invert the argument: a µ not so wrong = r p is not due to proton TPE or this kind of BSM after Pospelov Karshenboim, McKeen, Pospelov, arxiv Randolf Pohl Mainz, 2 nd June

63 Randolf Pohl Mainz, 2 nd June

CREMA collaboration in 2009 Charge Radius Experiment with Muonic Atoms F. KOTTMANN ETH Zürich, Switzerland D. TAQQU PSI, Switzerland A. ANTOGNINI, T.W. HÄNSCH, T. NEBEL, MPQ, Garching, Germany R.

64 CREMA collaboration in 2009 Charge Radius Experiment with Muonic Atoms F. KOTTMANN ETH Zürich, Switzerland D. TAQQU PSI, Switzerland A. ANTOGNINI, T.W. HÄNSCH, T. NEBEL, MPQ, Garching, Germany R. POHL E.-O. Le BIGOT, F. BIRABEN, P. INDELICATO, L. JULIEN, F. NEZ Laboratoire Kastler Brossel, Paris, France A. GIESEN, K. SCHUHMANN Dausinger + Giesen, Stuttgart, Germany T. GRAF Institut für Strahlwerkzeuge, Stuttgart, Germany F.D. AMARO, J.M.R. CARDOSO, D.S. COVITA, L.M.P. FERNANDES, J.A.M. LOPEZ, C.M.B. MONTEIRO, J.M.F. DOS SANTOS, J.F.C.A. VELOSO C.-Y. KAO, Y.-W. LIU Department of Physics, Coimbra, Portugal National Tsing Hua University, Hsinchu, Taiwan P. RABINOWITZ Department of Chemistry, Princeton, USA A. DAX, P. KNOWLES, L. LUDHOVA, former members, spent holidays at run 2009 F. MULHAUSER, L. SCHALLER Randolf Pohl Mainz, 2 nd June

The size of the proton

The size of the proton from the Lamb shift in muonic hydrogen Randolf Pohl The size of the proton from the Lamb shift in muonic hydrogen for the CREMA collaboration Randolf Pohl Max-Planck-Institut für