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Study on Exotic Hadrons at B-Factories

Study on Exotic Hadrons at B-Factories. Toru Iijima Nagoya University. February 5, 2010 NFQCD 10. Talk Outline. Experimental talk to introduce the status on cc-like mesons, recently found at B-factories. Introduction Exotics found in B decays Exotics found in other processes

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Study on Exotic Hadrons at B-Factories

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  1. Study on Exotic Hadrons at B-Factories Toru Iijima Nagoya University February 5, 2010 NFQCD 10

  2. Talk Outline Experimental talk to introduce the status on cc-like mesons, recently found at B-factories. • Introduction • Exotics found in B decays • Exotics found in other processes • XYZ counterparts in b/s sectors. Apologies: I cannot cover all of the results. Too many ! Presentation made mainly using Belle data.

  3. Belle 2006(532M BB) B0 tag _ B0 tag Achievement of the B-factories sin2f1= 0.642 ±0.031 (stat) ±0.017 (syst)

  4. Quest in low-energy QCD Are there exotics beyond meson(qq) /baryon (qqq) ? Sakata Model (p, n, L) 6 quark model I II III q=u, d, s, c, b, t u c t flavor up charm top Gell-mann (u,d,s) s b d color （R,G,B） strange down bottom New Hadrons（Exotics） Ordinal Hadrons Molecule Tetra-quark Penta-quark baryon meson q q q q QCDjust require hadrons to be colorless, and allow exotics. Why we don’t see them ? q We like to answer based on QCD

  5. New Hadrons from B-factories e+e- B factory is the ideal tool also to study new hadrons w/ heavy flavors ! Bonus discovery at B-factories Discoveries of new resonances at Belle Y(4660) Y(4008) Z(4430) DsJ(2860) DsJ(2700) Xcx(3090) Y(4320) cc2’ X(3940), Y(3940) Integrated luminosity (fb-1) Y(4260) Sc* baryon triplet X(3872) D0*0& D1*0 DsJ(2317/2460) hc’ & e+e-cccc

  6. Belle at KEKB • KEKB:asymmetric e+e- collider e+: 3.5 GeV  e-: 8.0 GeV √s=10.58 GeV = (4S) mass e+e-  (4S)  BB • Operating since 1999 • Peak luminosity: 2.111034cm-2s-1 • Integrated luminosity: 950 fb-1 710 fb-1 @ (4S) ~ 800 * 106 BB ~ 960 * 106 cc 553fb-1 at BaBar B-factory is also a charm factory

  7. Characteristic of the B-factory • Acceptance: 0.9 ×4p • Vertex resolution s(J/yll) ~75nm • Momentum resolution s(Pt) = 0.19・Pt  0.34/b % • Energy resolution s(Eg)/Eg =1.8% @ 1GeV • Particle ID e, m, p, K, p • Minimum bias trigger Evis >= 1GeV & Ntrk >= 2 & Ncluster >= 4 essentially no loss for BB.

  8. BX=ηcχcψ… W K Production of ccin B Factory • double cc production • e+e-→J/ψXcc • γγ collision • e+e-→γγ→Xcc→DD • B meson decays: B→XccK(BF~10-3) • initial state radiation (ISR) e+e-→γISRXcc→γISRψππ b c u, dc s u, d c γ* c c c e+ J/ψ X e- JPC(X)=0++, 0-+ Z(4430), Y(4140) γISR γ* π π ψ e+ e+ e- e- γ γ X D D J(X)=0, 2 C(X)=+1 X e+ e- JPC(X)=1-- Y(4140), Y(4350) Good experimental environment to search for new resonances

  9. XYZ found at B-factories • ~15 states have been claimed. • X(3872) has been the most extensively studied. • JPC = 1++ or 2+- • Decay to J/ y p p, J/ y g, DD*. • Charged states require the minimum configuration of ccud. • Z(4430)+ y’p+ • Z(4051)+, Z(4248)+  cc1p+ • Candidates of s- and b- counterparts • Y(2175)ff0(980) • Yb(10890)U(nS)pp

  10. Charmonia States found by ISR • All charmonium states below the DD threshold have been observed. • Most are narrow. • Spectra are in good agreement with naïve quark model • Above DD threshold • Many states are still empty • Expected to be broad and decay into DD. • Many of the observed cc-like states DO NOT; • Fit to the predicted spectrum. • Decay into D(*)D(*) final states. (2S+1)LJ M(MeV) y(4415) X(3872) Open charm thr. y(3770) h’c y’ cc2 hc cc1 cc0 J/y (pot. Models) hc JPC J=S+L P=(-1)L+1 C=(-1)L+S n(2S+1)LJ

  11. Possible Interpretation Tetraquark • Tetraquarks: diquark-antidiquark [cq][cq] • Tightly bound diquarks (gluon exchange) • Decay proceeds with „coloured” quarks rearrange into „white” mesons • Hybrids: cc+ excited gluon (excited flux-tube) • Lattice QCD predicts lightest hybrids @ 4.2GeV • Exotic quantum numbers JPC= 0+-, 1-+, 2+-… • Γ(H→DD**)> Γ(H→DD(*) ) • Large Γ(H→ψππ, ψω,… ) “Di-quark” D(*)D(*) Molecule • Molecules: M(cq)M(cq) • Meson and antimeson loosely bound (pion exchange) • Decay: dissociation into constituent mesons Hybrid

  12. X(3872) BKp+p-J/y y’ The 1st observation by Belle X(3872) M(p+p-J/y)-M(J/y) B decay is a gate way to exotic hadrons !

  13. 152M BB M(J/ψπ+π-) M(π+π-) 117MBB X(3872) • X(3872)→J/ψπ+π- observed in B+→X(3872)K+ by Belle • Confirmed by BaBar, CDF, D0 • mX=3871.2±0.5MeVmX-(mD*0+mD0)=-0.6±0.6MeVΓ<2.3MeV • M(π+π-) suggests X(3872)→J/ψρ (S- or P-wave) • Other decay modes: J/ψγ,ψ(2S)γ, J/ψω, DD*, no X→DD • JPC= 1++,2-+favored (from angular analysis by CDF, M(π+π-),decay modes) PRL91, 262001 (2003)

  14. X(3872) asD(*)D molecule ? N. A. Tornqvist PLB590, 209 (2004). “Deuson” • X(3872) is very close to DD* threshold (3871.2MeV). • Deuteron-like states found to be bound or nearly bound. • Large spatial size. • Hard to decay into non DD* final states • Width given by stability of components (D*) • Important decay should be D0D0p0 p D D* • Similar idea by • E. Swanson (2004), • E. Braaten & M. Kusunoki (2004), • M. Volosin (2004), • C. Thomas & F. Close (2008). • and others D D*

  15. B0→XK0 Ns=30±7 (6.5σ) B+→XK+ Ns=125±14 (12σ) First observation! 657MBB M(J/ψπ+π-) M(J/ψπ+π-) X(3872)in B+vs B0 decays hep-ex/0809.1224 • Study of X(3872)→J/ψπ+π- inB+→XK+ and B0→XK0s • Similar properties of X(3872) from B+ and B0 decays Maiani, Polosa et al. If tetra-quark, slight mass difference between

  16. Charged cc-like exotics Z(4430)+, Z(4051)+ & Z(4248)+ Required Minimum configuration: Z(4430) BK p± y’ M = 4433 ±4 ±2MeV Gtot = 45 +18 +30MeV Nsig =121 ± 30evts C2/dof=80.2/94.0 6.5  -13 -13 PRL 100, 142001(2008) M(py’) GeV

  17. A+C+E =K*veto M2(ψ’π+) More Recent Results • Maximum likelihood fit to the full Dalitz plot • Bψ’π+K amplitude: coherent sumof Breit-Wigner contributions • All known low-lying K* resonances: k, K*(892), K*(1410), K*0(1430), K*2(1430), K*(1680) • Fit is made w/ and w/o Zψ’π+ component. • Data favors the fit w/ Zψ’π+ component. Significance: 6.4σ A B C D E H G M2(ψ’π+) A B C D E F M2(K-π+ ) M2(ψ’π+) 2nd peak at m~4.3 GeV/c2 ?

  18. Results from Babar PRD79, 112001 (2009) • B→ψ’π+K studied using413/fb • Mass spectra corrected for efficiency Statistically consistent with Belle data. (χ2/ndf=54.7/58)

  19. Dalitz plot for B0K+cc1p- 657M BB DE sidebands M2(cc1p-) ?? M2(K+p-) K*(890)K+p- K*(892) K0*(1430)K+p- K2*(1430) R.Mizuk & R.Chistov arXiv:0806.4098 Submitted to PRD

  20. Cont’d M(χc1π+) for 1.0< M2(K-+) < 1.75GeV2 • Two resonances structure is distinctive (favored over one res. at the 5.7 s ) Mass & width Z1 Prod. Br. Z2 M(c1+) GeV/c2 Additional charmonium-like states with non-zero charge !

  21. Z+(4430) Z+(4430) confirmed Next step • Search for other decay modes • [cu][cd] tetra-quark? → neutral partner in ψ’π0 expected • D*D1(2420) molecule? → decay to D*D*π expected • Angular distribution →　JPC determination +1.8 +5.3 -0.9 -1.6 BF(B→KZ)xBF(Z→y(2S)p) = (3.2 ) x10-5

  22. Exotics found in • Double charm production • Reaction w/ Initial State Radiation • Two photon processes

  23. c γ* c c c e+ J/ψ X e- ee→J/ψDD* X(3940) 6.0σ ee→J/ψD*D* X(4160) 5.5σ M(D*D) M(D*D*) X(3940) & X(4160) ine+e-→J/ψXcc • X-sections much larger than QCD predicted → factory of 0++ and 0-+charmonia + others M=4156 ±15 MeV =139 ±21 MeV also cc- baryons ? M =3942 ± 6 MeV =37 ± 12 MeV +25 –20 +7 –6 PRL98, 082001 (2007) +111 – 61 +26 –15 357fb-1 Search for X→DD* and D*D* ine+e-→J/ψD(*)D* 693fb-1 PRL100, 202001 (2008) +DD* +D*D* J/y+DD +D*D* J/y+D*D • Possible assignments: ηc(3S) ηc(4S) (but X masses ~100-150MeV above predictions for ηc’s)

  24. M=4259 ± 8 MeV =88 ± 23 MeV +2 –6 +6 –4 γISR γ* π π ψ Y e+ e- PRL 95, 142001 (2005) for 232fb-1 Y family through ISR PRL 98, 212001 (2007) for 298fb-1 • ISR gives access to JPC=1-- states • Hard photon emission suppressed, • ‘compensated’ by high luminosity of B-factory Y(4260)→J/ψππ M=4324 ± 24 MeV =172 ± 33 MeV Y(4360)→ψ’ππ PRD74, 091104 (2006) PRL 96, 162003 (2006) for 13pb-1@4.26GeV

  25. 1--Y→ψππ states via ISR • Y(4008), Y(4260), Y(4360), Y(4660) • More 1– states than empty slots in cc spectrum Unusual properties: • Large widths for ψππ transition: unlike for conventional cc • Above DD threshold but don’t match the peaks in D(*)D(*) x-sections Other options: • DD1 or D*D0 molecules • cqcqtetraquarks • ccg hybrid: DD1decay mode should dominate • Coupled-channel effects • Charm-meson threshold effects e+e-→p+p-J/y Y(4260) Y(4008) e+e-→p+p-y’ Y(4360) Y(4660)

  26. Y(4140)  J/yf? • Possible partner of X(3872) Tetra-quark Molecule • CDF PRL102, 242002 (2009) 2.7 fb-1

  27. Search for Y(4140) → J/ y f • 476M BB • B  J/yf K Non-resonant J/ y f: non BJ/ y f K background Preliminary Signal at CDF mass @90%CL CDF

  28. Preliminary Y(4140) 825fb-1 Y(4140)→J/ψφ, Y(4350)→J/ψφ ? • Belle: search for Y(4140)→J/ψφ in γγ fusion • No Y(4140) signal [but efficiency drops at low J/ψφmass] • New Y(4350)? excited P-wave charmonim? Ds*Ds0* molecule? • e+e- undetected • pt balance required for final state

  29. Are there XYZ counterparts in strangeness and bottom sectors ?

  30. X(2175): strange analog of Y(4260)? • X(2175)→φ f0(980), φη(confirmed by BESII and Belle) PRD80, 031101 (R) (2009) PRD74, 091103 (2006)

  31. XYZ counterparts in b sectors ? • Energy scan: 10.811.0 GeV. • e+e-  U(1S) pp , U(2S) pp, U(3S) pp Belle preliminary

  32. More on Yb PRL 102, 012001 (2009) A.Ali, C.Hambrock, I.Ahmed, M.Aslam, PLB684, 28 (2010) • Rb scan by BaBar Fit w/ predicted Yb Resonances. If tetraquark ? • M(pp), cosqdistibution(Belle) • Yb U(2S) + pp • Yb U(1S) + pp A.Ali, C.Hambrock, M.Aslam arXiv:0912.5016 Fit w/ f0(600), f0(980), f2(1270) and non-reso. Energy scan in the next FY year under discussion.

  33. Outlook cf) talk by R. Faccini at FPCP09 • We are at the stage of findings these “exotics”. Don’t know yet what they are… • There will be more to be found. • Near threshold • Bound states ? • To elucidate, need more detail information about production & decays. • Production rate in each process • Decay modes • Angular distribution Plenty of states seen with low-stat. and in only one channel. More analyses using full data at the present B factories And much more information at Super B Factories !

  34. Super B Factory Target luminosity：8×1035cm-2s-1 Lint = 1050ab-1 ~15x1010t+t- pairs

  35. Colliding bunches New Superconducting / permanent final focusing quads near the IP e- 2.1 A Nano-Beam SuperKEKB e+ 3.7 A Replace long TRISTAN dipoles with shorter ones (HER). Add / modify rf systems for higher currents. Low emittance positrons to inject Redesign the HER arcs to squeeze the emitance. Low emittance gun Low emittance electrons to inject New positron target / capture section x40 Gain in Luminosity TiN coated beam pipe with antechambers

  36. Machine Parameters High Current Option includes crab crossing and travelling focus. Nano-Beam Option does not include crab waist.

  37. Belle Upgrade Better background tolerance Better performance 日本,台湾,ロシア ECL Wave sampling + pure CsI crystal(endcap) PID Threshold Aerogel + TOF →　TOP + Aerogel-RICH 日本,ロシア, US KL/m detection RPC → Scintillator +SiPM(endcap) 日本,スロベニア,US CDC Super small cell Longer lever arm New Dead time free readout and high speed computing systems 日本 SVD 4-lyr DSSD → 6lyr DSSD (option: striplet / pixel ) 日本,韓国,スペイン,ドイツ,チェコ,ポーランド,オーストリア,US,インド

  38. Summary • KEKB/Belle, together with PEP II/BaBar and other exp’s, have observed many new hadron resonances, which cannot be explained by conventional meson pictures. • Some of them must be exotics, requiring the minimum contents of 4 quarks: ex.) Z(4430)+ • Similar states in s- and b-quark sectors are seen. • A large data sample at hand • More to be analyzed (more production/decay channels, more topics) • Will continue providing interesting results in coming years. • In future, Super B factories (+ tau-charm) will provide • Search for more states. • Study on detail properties of observed states.

  39. New Initiative Grant-in-aid for innovative scientific research area ”Elucidation of new hadrons with a variety of flavors”. We welcome your contribution ! Visit our home page ! http://www.hepl.phys.nagoya-u.ac.jp/public/new_hadron/index.html

  40. Backup

  41. From Hadron Physics Point of View B factory is an ideal place to study “new hadrons” with • High luminosity • Ideal measurements (clean environment, 4-p detector, PID etc.). At Super-B factory; • More states with different • Flavor configuration ? • # quarks ? • Detail property of observed states • Decay modes • Spin, Parity Etc. … Also, 5-quark ? 6-quark ? … #quarks flavor New inter-disciplinary area @ KEKB, LEPS, J-PARC ! Probing new hadron states w/ flavors

  42. PRD77,011103(2008) DD ? DD* (4160) Y(4350) PRL98, 092001 (2007) Y(4008) D*D* Y(4260) (4415) (4040) PRL100,062001(2008) Y(4660) DDπ arXiv:0807.4458 Λc+Λc– NEW Exclusive x-sections with ISR PRD 77, 011103 (2008) for 673fb-1 • Difficult interpretation in terms of resonances (model dependent coupled-channel and threshold effects…) PRL 98, 092001 (2007) for 548fb-1 PRL 100, 062001 (2008) for 673fb-1

  43. ΔE Mbc ΔE Mbc How to identify B meson signal • Advantage of e+e-→(4S) → BBkinematics: m(4S)~mB+mB no accompanying particles → EB=Ebeam=√s/2in cms • kinematical variables used in B-Factories Mbc= √E2beam- p2B beam-constrained mass (signal at mB~5.28GeV) ΔE=EB- Ebeam cms energy difference (signal peaks at 0) • Resolution improvement (Ebeam is precisely known) • Background separation Example: B0→J/ψ KS

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