Measuring the phase between strong and EM J/ψ decay amplitudes HADRON 2011

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1 Measuring the phase between strong and EM J/ψ decay amplitudes Marco Maggiora on behalf of the BESIII Collaboration Dep. of General Physics, University of Turin and INFN, Turin XIV International Conference on Hadron Spectroscopy Künstlerhaus - Munich, June 13 th - 17 th, 11

2 J/ψ strong and electromagnetic decay amplitudes strong A3g Resonant contributions Φp (GpM ) Φγ Φ3g = hadrons Φγ : relative A3g Ap J/ψ N N Φp = 89 ± 15 J/ψ VP (1 ) Φp = 6 ± electromagnetic Aγ J/ψ PP ( ) Φp = 89.6 ± 9.9 J/ψ VV (1 1 ) Φp = 138 ± 37 hadrons NO INTERFERENCE! Non-resonant continuum non-resonant continuum AQED affects the measured BR [4] hadrons affects Φp [] [3] [3] [4] INTERFERENCE WITH A3g! R. Baldini, C. Bini, E. Luppi, Phys. Lett. B44, 36 (1997); R. Baldini et al., Phys. Lett. B444, 111 (1998). L. Kopke and N. Wermes, Phys. Rep. 174, 67 (1989); J. Jousset et al., Phys. Rev. D41,1389 (199). [3] M. Suzuki et al., Phys. Rev. D6, 5151 (1999). [4] P. Wang, arxiv:hep-ph/48v and references therein. []

3 J/ψ strong and electromagnetic decay amplitudes IMAGINARY AMPLITUDES HARD TO BE EXPLAINED! J/ψ perturbative regime ( ΓJ/ψ 93KeV ) pqcd real Aγ, A3g QCD does not provide sizeable imaginary amplitudes (Φp at most ) a J/ψ V glueball mixing [] may explain imaginary amplitudes; and ψ? determination of phases Φp rely on theoretical hypotheses EXPERIMENTAL DATA no interference term in the inclusive J/ψ and ψ production early evidence of an interf. term in e+ e J/ψ µ+ SLAC [3] no clear evidence of interf. or glueball in e+ e J/ψ BESII [4] J. Bolz and P. Kroll, WU B S.J. Brodsky, G.P. Lepage, S.F. Tuan, Phys. Rev. Lett. 59, 61 (1987). [3] M. Boyarski et al., Phys. Rev. Lett. 34, 1357 (1975). [4] J.Z. Bai et al., Phys. Rev. D 54, 11 (1996). [] 3

4 J/ψ strong and electromagnetic decay amplitudes x= {z MJ/ψ s ΓTOT / AR = α } resonant x 1+x 1 + i 1+x {z } non resonant ΦAγ Φp = ΦGpM ANR = βeiφp p β = σ (e+ e pp ) A sin Φ γ p Φα = arctan A3g + A γ cos Φp GpM W MJ/ψ {z } Φ = Φp Φα Φp Φ I(x) = AR + ANR = βα α + β (x cos Φ + sin Φ) 1 + x 1 + x Φp S.J. Brodsky, G.P. Lepage, S.F. Tuan, Phys. Rev. Lett. 59, 61 (1987). 4

5 Simulated e+ e N s MJ/ψ interference must have opposite sign as magnetic moments σ(nn) (nb) φ = 18 φ= o _ o _ σ(pp) (nb) φ = 9 o 1 φ= o φ = 18o -1-1 φ = 9o E Ec.m. (MeV) (MeV) c.m. continuum reference: σ e+ e pp 11 pb continuum reference: σ e+ e nn 5 pb [1,] radiative corrections and beam energy spread (BESIII) included! [] B. Aubert et al. [BABAR Collaboration], Phys. Rev. D 73, 15 (6). R. Baldini, S. Pacetti, A. Zallo, arxiv: [hep-ph]. 5

6 Simulated e+ e s MJ/ψ - BESIII scenario no correction beam energy spread beam energy spread + radiative corrections CORRECTIONS NEEDED! small effects from beam energy spread significant suppression from radiative corrections 6

7 _ e e pp Ec.m. = 39 MeV Lint = pb Number of sigmas Events Simulated e+ e s MJ/ψ ( pb 1 ) _ e e pp Ec.m. = 39 MeV Lint = pb φ (deg) 15 φ (deg) continuum reference: σ (e+ e pp ) 11 pb radiative corrections and beam energy spread (BESIII) included! B. Aubert et al. [BABAR Collaboration], Phys. Rev. D 73, 15 (6). 7

8 _ e e nn Ec.m. = 39 MeV Lint = pb Number of sigmas Events Simulated e+ e s MJ/ψ ( pb 1 ) 6 _ e e nn Ec.m. = 39 MeV Lint = pb φ (deg) 15 φ (deg) continuum reference: σ (e+ e nn ) 5 pb [1,] radiative corrections and beam energy spread (BESIII) included! [] B. Aubert et al. [BABAR Collaboration], Phys. Rev. D 73, 15 (6). R. Baldini, S. Pacetti, A. Zallo, hep-ph81.38v. 8

9 σ(ρπ) (nb) Simulated e+ e s MJ/ψ φ = 18o φ = 9o φ = o Ec.m. (MeV) continuum reference: σ (e+ e ρπ) pb radiative corrections and beam energy spread (BESIII) included! J.Z. Bai et al., Phys. Rev. D 54, 11 (1996). 9

10 Number of sigmas Events Simulated e+ e s MJ/ψ ( pb 1 ) e e ρπ Ec.m. = 383 MeV Lint = pb e e ρπ Ec.m. = 383 MeV Lint = pb φ (deg) 15 φ (deg) continuum reference: σ (e+ e ρπ) pb radiative corrections and beam energy spread (BESIII) included! J.Z. Bai et al., Phys. Rev. D 54, 11 (1996).

11 BEPCII: e+ e double ring collider Design Features Beam energy: GeV Crossing angle: mrad (DAΦNE 5 mrad) Luminosity: 33 cm s 1 Optimum energy: 1.89 GeV Energy spread: Number of bunches: 93 Bunch length: 1.5 cm Total current:.91 A 11

12 The BESIII detector Magnet yoke s RPC (9/8 layers Barrel/Endcaps) s s s s s s s SC magnet, 1 Tesla TOF (scintillators), 9 ps Be beam pipe s s MDC, 1µm s CsI(Tl) calorimeter,.5% at 1 GeV A significant improvement with respect to BESII 1

13 BEPCII / BESIII milestones Mar. 8: Apr. 3, 8: July 18, 8: Apr. 14, 9: July 8, 9: -11: May, 11: Collisions at 5 ma 5 ma, Luminosity: 1 3 cm s 1 Move BESIII to IP First e + e collision event in BESIII 6 M ψ events (15pb 1 ) ( 4pb 1 at 3.65 GeV) 5 M J/Ψ events (65pb 1 ).9fb 1 at ψ ( 7pb 1 scanning in the ψ energy region).5fb 1 at 4.1 GeV (Ds and XYZ spectroscopy) Record Luminosity on Apr 7, cm s 1 or 8 CESRc 45 BEPC 13

14 World J/Ψ and ψ Samples ( 6 ) BESIII: BESII: BESIII: BESII: 6 M ψ events (15pb 1 ) 14 M ψ events 5 M J/Ψ events (65pb 1 ) 58 M J/Ψ events J/ψ ψ 14

15 HESR - High Energy Storage FAIR Production rate 7 /s pbeam = 1 15 Gev /c Nstored = 5 p Internal pellet target High resolution mode δp/p 5 (electron cooling) Luminosity 31 cm s 1 High luminosity mode Luminosity 3 cm s 1 δp/p 4 (electron cooling) 15

16 The PANDA Detector Physics Performance Report for PANDA: Strong Interaction Studies with Antiprotons, arxiv:

17 Simulated e+ e PANDA and BESIII BESIII scenario strong suppression of interference many channels accessible PANDA scenario large un-suppressed interference pp only 17

18 Summary scan around interference dip (all exclusive channels for free!) at least one point far enough from MJ/ψ ( MeV ) for continuum reference model independent evaluation of interference reference channel: e+ e pp QUOTED RESULTS relative to pb 1 Thank you! 18

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20 FENICE data on e+ e N s MJ/ψ Predictions for Φp making use of FENICE data R GnM = 1.5 GpM GnM = 1.5 GpM 6 Φp 9 R. Baldini, C. Bini, E. Luppi, Phys. Lett. B44, 36 (1997). R= σ (e+ e nn ) σ (e+ e pp ) Φp

21 Early evidence of interference in e+ e µ+ µ e+ e hadrons e+ e µ+ µ J/ψ SPEAR (SLAC) e+ e e+ e R. Baldini, C. Bini, E. Luppi, Phys. Lett. B44, 36 (1997). 1

22 σpp(s) (nb) Simulated e+ e s MJ/ψ ( pb 1 ).8 σpp(3. GeV) =.7 ±.6 pb s1/ (GeV) B. Aubert et al. [BABAR Collaboration], Phys. Rev. D 73, 15 (6).

23 The BESII and BESIII detectors BEPC Device MDC TOF EMC MUC Magnet Performance q 1 + p, de/dx = 8% σp /p = 1.7% 18 ps (bhabha) σe /E < %/ E 3 layers.4 T Solenoidal BEPCII Device MDC TOF EMC MUC Magnet Performance σp /p =.5%, de/dx < 6% 8 ps barrel (bhabha), ps endcap σe /E <.5%/ E 9 barrel + 8 endcap layers 1 T Solenoidal 3