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1 Bottomonium and bottomonium–like states Alex Bondar On behalf of Belle Collaboration Cracow Epiphany Conference “Present and Future B-physics” (9 - 11, January, 2012, Cracow, Poland )
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2 Observation of h b (1P) and h b (2P) Outline (5S) Z b (10610) + - Z b (10650) + - (1S) + - (2S) + - (3S) + - h b (1P) + - b (1S) + - h b (2P) + - arXiv:1103.3419 accepted by PRL at BB* and B*B* thresholds molecules Observation of Z b arXiv:1105.4583 final state w/ h b (nP) and (nS) angular analysis accepted by PRL Observation of h b (1P) b (1S) arXiv:1110.3934 arXiv:1110.2251
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3 PRL100,112001(2008) (MeV) 10 2 PRD82,091106R(2010) Anomalous production of (nS) + - 1. Rescattering (5S) BB (nS) ? Simonov JETP Lett 87,147(2008) 2. Similar effect in charmonium? shapes of R b and ( ) different (2 ) to distinguish energy scan (5S) line shape of Y b Y(4260) with anomalous (J/ + - ) assume Y b close to (5S)
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4 h b (1P) & h b (2P) Observation of
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5 Trigger Y(4260) Y b search for h b (nP) + - @ (5S) CLEO observed e + e - → h c + – @ E CM =4170MeV PRL107, 041803 (2011) (h c + – ) (J/ + – ) 4260 Hint of rise in (h c + - ) @ Y(4260) ? Y(4260)
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6 MM( + - ) Introduction to h b (nP) (bb) : S=0 L=1 J PC =1 + M HF test of hyperfine interaction For h c M HF = 0.00 0.15 MeV, expect smaller deviation for h b (nP) _ Expected mass (M b0 + 3 M b1 + 5 M b2 ) / 9 (3S) → 0 h b (1P) BaBar 3.0 arXiv:1102.4565 PRD 84, 091101 Previous search
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7 MM( + - ) Introduction to h b (nP) (bb) : S=0 L=1 J PC =1 + M HF test of hyperfine interaction For h c M HF = 0.00 0.15 MeV, expect smaller deviation for h b (nP) _ Expected mass (M b0 + 3 M b1 + 5 M b2 ) / 9 (3S) → 0 h b (1P) BaBar 3.0 arXiv:1102.4565 PRD 84, 091101 Previous search
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8 (5S) h b + - reconstruction h b → ggg, b (→ gg) no good exclusive final states reconstructed “Missing mass” M(h b ) = (E c.m. – E + - ) 2 – p + - ** 2 M miss ( + - ) (1S) (2S) (3S) h b (2P)h b (1P)
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9 Results 121.4 fb -1 h b (1P) 5.5 h b (2P) 11.2 Significance w/ systematics
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10 Hyperfine splitting h b (1P) (1.7 1.5) MeV/c 2 h b (2P) (0.5 +1.6 ) MeV/c 2 -1.2 Deviations from CoG (Center of Gravity) of bJ masses consistent with zero, as expected Ratio of production rates Mechanism of (5S) h b (nP) + - decay violates Heavy Quark Spin Symmetry for h b (1P) for h b (2P) no spin-flip = spin-flip Process with spin-flip of heavy quark is not suppressed
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11 Resonant structure of (5S) h b (nP) + -
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12 Resonant structure of (5S) h b (1P) + - M(h b – ), GeV/c 2 phase-space MC M(h b + ), GeV/c 2
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13 Resonant structure of (5S) h b (1P) + - Results MeV 2 = non-res.~0 Fit function ~BB* threshold _ ~B*B* threshold __ 1 = MeV MeV/c 2 M 2 = M 1 =MeV/c 2 a = = degrees Significance (16 w/ syst)18 121.4 fb -1 M(h b – ), GeV/c 2 phase-space MC M(h b + ), GeV/c 2 fit M miss ( + – ) in M(h b ) bins M(h b ), GeV/c 2 h b (1P) yield / 10MeV Z b (10610), Z b (10650)
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14 Resonant structure of (5S) h b (2P) + - Significances (5.6 w/ syst)6.7 M(h b – ), GeV/c 2 phase-space MC M(h b + ), GeV/c 2 fit M miss ( + – ) in M(h b ) bins 121.4 fb -1 M(h b ), GeV/c 2 h b (1P) yield / 10MeV non-res.~0 h b (1P) + - h b (2P) + - non-res. set to zero degrees MeV/c 2 MeV c o n s i s t e n t MeV 2 = 1 = MeV MeV/c 2 M 2 = M 1 =MeV/c 2 a = = degrees MeV
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15 Resonant structure of (5S) (nS) + - (n=1,2,3)
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16 (5S) (nS) + - +- +- (n = 1,2,3) (1S) (2S) (3S) reflections M miss ( + - ), GeV/c 2
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17 (1S) (2S) (3S) (5S) (nS) + - (n = 1,2,3) M miss ( + - ), GeV/c 2 purity 92 – 94% +- +-
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18 (5S) (nS) + - Dalitz plots (1S) (2S) (3S)
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19 (5S) (nS) + - Dalitz plots (1S) (2S) (3S) Signals of Z b (10610) and Z b (10650)
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20 heavy quark spin-flip amplitude is suppressed Fitting the Dalitz plots Signal amplitude parameterization: S(s1,s2) = A(Z b1 ) + A(Z b2 ) + A(f 0 (980)) + A(f 2 (1275)) + A NR A NR = C 1 + C 2 ∙m 2 (ππ) Parameterization of the non-resonant amplitude is discussed in [1] M.B. Voloshin, Prog. Part. Nucl. Phys. 61:455, 2008. [2] M.B. Voloshin, Phys. Rev. D74:054022, 2006. A(Z b1 ) + A(Z b2 ) + A(f 2 (1275)) A(f 0 (980)) – Breit-Wigner – Flatte (5S) Z b , Z b (nS) – no spin orientation change S-wave Spins of (5S) and (nS) can be ignored Angular analysis favors J P =1 + Non-resonant
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21 Results: (1S)π + π - M( (1 S)π + ), GeV M( (1S)π - ), GeV signals reflections
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22 Results: (2S)π + π - reflections signals M( (2S)π + ), GeV M( (2S)π - ), GeV
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23 Results: (3S)π + π - M( (3S)π + ), GeV M( (3S)π - ), GeV
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24 M 1 = 10607.2 2.0 MeV 1 = 18.4 2.4 MeV M 2 = 10652.2 1.5 MeV 2 = 11.5 2.2 MeV Summary of Z b parameters Average over 5 channels
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25 M 1 = 10607.2 2.0 MeV 1 = 18.4 2.4 MeV M 2 = 10652.2 1.5 MeV 2 = 11.5 2.2 MeV Z b (10610) yield ~ Z b (10650) yield in every channel Relative phases: 0 o for and 180 o for h b Summary of Z b parameters Average over 5 channels M(h b ), GeV/c 2 h b (1P) yield / 10MeV = 180 o = 0 o
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26 Angular analysis
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27 Angular analysis Example : (5S) Z b + (10610) - [ (2S) + ] - (0 is forbidden by parity conservation) Color coding: J P = 1 + 1 - 2 + 2 - Best discrimination: cos 2 for 1 - (3.6 ) and 2 - (2.7 ); non-resonant combinatorial cos 1 cos 2 rad cos 1 for 2 + (4.3 ) i ( i,e + ), [plane( 1,e + ), plane( 1, 2 )] Definition of angles
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28 Summary of angular analysis All angular distributions are consistent with J P =1 + for Z b (10610) & Z b (10650). All other J P with J 2 are disfavored at typically 3 level. Probabilities at which different J P hypotheses are disfavored compared to 1 + procedure to deal with non-resonant contribution is approximate, no mutual cross-feed of Z b ’s Preliminary:
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29 Heavy quark structure in Z b Wave func. at large distance – B(*)B* A.B.,A.Garmash,A.Milstein,R.Mizuk,M.Voloshin PRD84 054010 (arXiv:1105.4473) Why h b is unsuppressed relative to Relative phase ~0 for and ~180 0 for h b Production rates of Z b (10610) and Z b (10650) are similar Widths –”– Existence of other similar states Explains Predicts Other Possible Explanations Coupled channel resonances (I.V.Danilkin et al, arXiv:1106.1552) Cusp (D.Bugg Europhys.Lett.96 (2011),arXiv:1105.5492) Tetraquark (M.Karliner, H.Lipkin, arXiv:0802.0649)
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30 Observation of h b (1P) b (1S)
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31 Introduction to b Godfrey & Rosner, PRD66 014012 (2002) h b (1P) → ggg (57%), b (1S) (41%), gg (2%) h b (2P) → ggg (63%), b (1S) (13%), b (2S) (19%), gg (2%) Expected decays of h b Large h b (mP) samples give opportunity to study b (nS) states. Experimental status of b M[ b (1S)] = 9390.9 2.8 MeV (BaBar + CLEO) M[ (1S)] – M[ b (1S)] = 69.3 2.8 MeV Width of b (1S): no information pNRQCD: 41 14 MeV Lattice: 60 8 MeV Kniehl et al., PRL92,242001(2004)Meinel, PRD82,114502(2010) (3S) b (1S)
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32 Method reconstruct b (mS) (5S) Z b - + h b (nP) + Decay chain Use missing mass to identify signals M( b ) M(h b ) true + - fake fake + - true true + - true MC simulation
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33 Method reconstruct b (mS) (5S) Z b - + h b (nP) + Decay chain Use missing mass to identify signals M( b ) M(h b ) true + - fake fake + - true true + - true MC simulation M miss ( + - ) M miss ( + - ) – M miss ( + - ) + M[h b ]
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34 Method reconstruct b (mS) (5S) Z b - + h b (nP) + Decay chain Use missing mass to identify signals M( b ) M(h b ) MC simulation M miss ( + - ) M miss ( + - ) – M miss ( + - ) + M[h b ] Approach: fit M miss ( + - ) spectra in M miss ( + - ) bins h b (1P) yield vs. M miss ( + - ) search for b (1S) signal
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35 Results b (1S) 13 potential models : = 5 – 20 MeV Godfrey & Rosner : BF = 41% BaBar (3S) b (1S) BaBar (2S) CLEO (3S) BELLE preliminary pNRQCDLattice N.Brambilla et al., Eur.Phys.J. C71(2011) 1534 (arXiv:1010.5827) M HF [ b (1S)] = 59.3 1.9 +2.4 MeV/c 2 –1.4
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36 Observation of two charged bottomonium-like resonances in 5 final states M = 10607.2 2.0 MeV = 18.4 2.4 MeV M = 10652.2 1.5 MeV = 11.5 2.2 MeV First observation of h b (1P) and h b (2P) Hyperfine splitting consistent with zero, as expected Anomalous production rates arXiv:1103.3419 accepted by PRL arXiv:1105.4583, arXiv:1110.2251, accepted by PRL Summary (1S)π +, (2S) π +, (3S)π +, h b (1P) +, h b (2P) + Angular analyses favour J P = 1 +, decay pattern I G = 1 + Masses are close to BB* and B*B* thresholds – molecule? Observation of h b (1P) b (1S) The most precise single meas., significantly different from WA, decreases tension w/ theory Will Z b ’s become a key to understanding of all other quarkonium-like states? arXiv:1110.3934 Z b (10610)
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37 Back up
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38 (5S) (6S) (?S) I G (J P ) B*B* BB* BB 0 - (1 + ) 1 + (1 + ) 0 + (0 + )1 - (0 + )0 + (1 + )1 - (1 + )0 + (2 + )1 - (2 + ) 12GeV 11.5GeV ZbZb W b0 W b1 W b2 h b b b b b arXiv:1105.5829 XbXb 0 - (1 - )
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40 Coupled channel resonance? I.V.Danilkin, V.D.Orlovsky, Yu.Simonov arXiv:1106.1552 No interaction between B(*)B* or is needed to form resonance No other resonances predicted B(*)B* interaction switched on individual mass in every channel?
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41 Cusp? D.Bugg Europhys.Lett.96 (2011) (arXiv:1105.5492) Amplitude Line-shape Not a resonance
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42 Tetraquark? M ~ 10.5 – 10.8 GeV Tao Guo, Lu Cao, Ming-Zhen Zhou, Hong Chen, (1106.2284) M ~ 10.2 – 10.3 GeV Ying Cui, Xiao-lin Chen, Wei-Zhen Deng, Shi-Lin Zhu, High Energy Phys.Nucl.Phys.31:7-13, 2007 (hep-ph/0607226) M ~ 9.4, 11 GeV M.Karliner, H.Lipkin, (0802.0649)
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43 Selection Require intermediate Z b : 10.59 < MM( ) < 10.67 GeV ZbZb Hadronic event selection; continuum suppression using event shape; 0 veto. R 2 <0.3 reconstruct b (mS) (5S) Z b - + h b (nP) + Decay chain bg. suppression 5.2
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44 M miss ( + - ) spectrum requirement of intermediate Z b Update of M [h b (1P)] : Previous Belle meas.: h b (1P) 3S 1S (2S) M HF [h b (1P)] = (+0.8 1.1)MeV/c 2 M HF [h b (1P)] = (+1.6 1.5)MeV/c 2 arXiv:1103.3411
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45 Results of fits to M miss ( + - ) spectra no significant structures b (1S) h b (1P) yield Reflection yield (2S) yield Peaking background? MC simulation none.
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46 Calibration B + c1 K + (J/ ) K + Use decays match energy of signal & callibration channelscos Hel ( c1 )> – 0.2 h b (1P) b (1S) cos Hel > – 0.2 MC simulation c1 J/ Photon energy spectrum
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47 Calibration (2) data Correction of MC E s.b. subtracted fudge-factor for resolution M(J/ ), GeV/c 2 –0.4 mass shift –0.7 0.3 +0.2 MeV 1.15 0.06 0.06 Resolution: double-sided CrystalBall function with asymmetric core
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48 BsBs Integrated Luminosity at B-factories > 1 ab -1 On resonance: (5S): 121 fb -1 (4S): 711 fb -1 (3S): 3 fb -1 (2S): 24 fb -1 (1S): 6 fb -1 Off reson./scan : ~100 fb-1 530 fb -1 On resonance: (4S): 433 fb -1 (3S): 30 fb -1 (2S): 14 fb -1 Off reson./scan : ~54 fb-1 (fb -1 ) asymmetric e + e - collisions
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49 ( 5S ) Belle took data at E=10867 1 MэВ 2M(B s ) BaBar PRL 102, 012001 (2009) ( 6S ) ( 4S ) e + e - hadronic cross-section main motivation for taking data at (5S) ( 1S ) ( 2S ) ( 3S ) ( 4S ) 2M(B) e + e - -> (4S) -> BB, where B is B + or B 0 e + e - -> bb ( (5S)) -> B ( * ) B ( * ), B ( * ) B ( * ) , BB , B s ( * ) B s ( * ), (1S) , X … _ _____
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50 Residuals (1S) Example of fit Description of fit to MM( + - ) Three fit regions 123 Ks generic (3S) kinematic boundary MM( + -) M( + -) MM( + -) BG: Chebyshev polynomial, 6 th or 7 th order Signal: shape is fixed from + - + - data “Residuals” – subtract polynomial from data points K S contribution: subtract bin-by-bin
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Y(5S) → Y(2S)π + π - Results: Y(5S) → Y(2S)π + π - 51
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Y(5S) → Y(2S)π + π - Results: Y(5S) → Y(2S)π + π - 52
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