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Decays at CLEO Steve Blusk Syracuse University for the CLEO Collaboration Preview Introduction Measurements of B ( (nS) + - ) Electric Dipole Transitions (1S) ( c c ) + X Summary Preview Introduction Measurements of B ( (nS) + - ) Electric Dipole Transitions (1S) ( c c ) + X Summary ICHEP’04, Beijing, China Aug 16-22,2004
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Bottomonium J PC 1 -- (bb) states couple to virtual photon (1S)- (3S) too light to form B mesons ggg and qq decays dominant, but suppressed. States are narrow ! EM and hadronic transitions to lower-lying bb states competitive (4S) BB; Weak Int. Physics n 2S+1 L J J=L+S Photon Transitions E1: | L|=1, S=0: M1: L=0, | S|=1: E1 >> M1 Hyperfine (spin-spin) splitting Spin-orbit 3 P J 3 P 0,1,2 CLEO III
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Detector & Data Samples (1S) (2S) (3S) 10 6 Analyses presented here make extensive use of the excellent CsI calorimeter, tracking and muon systems CsI: 6144 crystals (barrel only): E /E ~ 4% at 100 MeV ~2.5% at 1 GeV Tracking
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Measurement of B ( (nS) ) Goal: Extract tot. of (nS). tot << E beam cannot be extracted by scanning the resonance. Use: tot = ee / B ee = ee / B where B ll =B ( (nS) + - ); (assumes lepton universality) B ( (nS) ) also important for (nS) EM & hadronic BF’s. We actually measure: Which is related to B by: (nS) Event Selection Exactly 2 back-to-back oppositely charged muons 50 MeV (nS) hadrons Event Selection >2 charged tracks For N trk <5: (E cc > 0.15E cm ) & (E cc <0.75E cm or E sh max <E beam ) E visible > 0.2E cm (nS) efficiency: (65.2±0.2)% (nS) hadrons efficiency: (97-98)% Background dominated by cascade decays: e.g. (2S) (1S) 0 0 / (2S) : (2.9±1.5)% (3S) : (2.2±0.7)% N sh < 2 N sh 2 M /E beam (2S) (1S)X, (1S) (2S) (2S) Data ICHEP ABS10-0774
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B (%) Results (1S) (2S) (3S) N 344,908 ± 2485119588 ± 183781179 ± 2660 0.652 ± 0.002 N had 18,957,575 ± 117297,838,270 ± 88034,641,369 ± 12645 had 0.979 ± 0.0160.965 ± 0.0130.975 ±.014 Interference corr.0.9840.9610.982 B (%) 2.49 0.02 0.072.03 0.03 0.082.39 0.07 0.10 tot (keV) 52.8 ± 1.829.0 ± 1.620.3 ± 2.1 PDG tot (keV) 53.0 ± 1.543.0 ± 6.026.3 ± 3.4 (1S) in good agreement with previous measurements (2S), (3S) significantly larger than current world average values
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Electromagnetic Transitions Aim is to get precision measurements of masses and transition rates. Tests of LQCD & effective theories, such as potential models or NRQCD. We present results on Inclusive Analyses of E1 transitions: (2S) bJ (1P) (3S) bJ (1,2P) Can be used to extract E1 matrix elements and extract relative importance of spin-orbit and tensor interactions. C. Davies, et al, PRL 92. 022001 (2004)
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Inclusive (2S) bJ (1P) e+e-e+e- hadrons (2S) Branching Fraction (%) Photon energy (MeV) b0 (1P)3.75 0.12 0.47162.56 0.19 0.42 b1 (1P)6.93 0.12 0.41129.58 0.09 0.29 b2 (1P)7.24 0.11 0.40110.58 0.08 0.30 Raw Background subtracted hadrons Preliminary Dominant Systematics B: Shower Simulation & Fitting E : Calorimeter calibration
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(3S) Branching Fraction (%) Photon energy (MeV) b0 (2P)6.77 0.20 0.65121.55 0.16 0.46 b1 (2P)14.54 0.18 0.7399.15 0.07 0.25 b2 (2P)15.79 0.17 0.7386.04 0.06 0.27 b0 (1P)0.30 0.04 0.10 - Inclusive (3S) bJ (1,2P) (2S) b (1P J ) (1D J ) b (1P j ) (3S) b (1P 0 ) (3S) b (1P 2 ) + (3S) b (1P 1 ) + b (1P J ) (1S) (3S) bJ (2P) (3S) bJ (1P) 100 50 200 E MeV Preliminary
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Summary of (2S) bJ (1P) Results (Preliminary) EE EE B B (2S) b (1P 2 ) (2S) b (1P 1 ) (2S) b (1P 0 ) Gives quantitative information on the relative importance of spin-orbit & tensor forces
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Summary of (3S) bJ (2P) Results (Preliminary) EE EE B B (3S) b (2P 2 ) (3S) b (2P 1 ) (3S) b (2P 0 )
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Charmonium Production in (1S) Decay History: CDF observes J/ , (2S) ~10x, 50x too large. Braaten & Fleming propose color-octet (CO) mechanism; J/ produced perturbatively in CO state and radiates a soft-gluon (non-perturbatively) to become a color-singlet (CS); fit to data. Problems though: J/ polarization data from CDF, e + e - J/ +X from BaBar & Belle, J/ at HERA. Suggestion by Cheung, Keung, & Yuan: If CO is important, the glue-rich decays of should provide an excellent labortatory for studying the role of the CO mechanism in production. Distinct signatures in J/ momentum spectrum (peaking near endpoint). Li, Xie & Wang show that the Y(1S) J/ +ccg may also be important (2 charm pairs) Li, Xie & Wang, PLB 482, 65 (2000) Cheung, Keung & Yuan, PRD 54 929 (1996) B ( (1S) J/ +X) 6.2x10 -4 5.9x10 -4 Momentum Spectrum SoftHard Previous CLEO measurement based on ~20 J/ events: B =(11±4)x10 -4 ICHEP ABS10-0773
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Event Selection & Signals Data Sample: 21.2x10 6 (1S) decays Reconstruct J/ , e + e - Backgrounds: Radiative return: suppressed through N trk, E max, and P ev miss requirements Radiative Bhabha (ee only): veto events where either electron can form M(e + e - )<100 MeV. cJ : Negligible after N trk and P ev miss requirements. e + e - J/ +X continuum: Estimated using (4S) data and subtracted. Efficiencies: ~40% (~50%) for J/ (J/ ee); small dependence on momentum, cos (1S) J/ +X e + e - J/ +X below Y(4S)
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(1S) J/ +X B ( (1S) J/ +X)=(6.4±0.4±0.6)x10 -4 Spectrum much softer than CO prediction Somewhat softer than CS prediction Very different from continuum Continuum Background (e + e - J/ +X)=1.9±0.2(stat) pb BaBar (e + e - J/ +X)=2.52±0.21±0.21 pb, PRL87, 162002 (2001) Belle (e + e - J/ +X)=1.47±0.10±0.13 pb, PRL88, 052001 (2002) Normalization to (1S) Data * Luminosity ratio * Phase space ratio: 0.78±0.13 BaBar
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First Observations/Evidence (1S) (2S)+X (1S) cJ +X CO & CS both predict ~20% c1, c2 BF’s ~2x CO prediction (4S) Continuum
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Summary CLEO has the world’s largest sample of (1S), (2S), and (3S) data sets Precision measurements in (bb) spectroscopy (rates, masses) provides a unique laboratory for probing QCD. Glue-rich environment is ideal for studying color-octet predictions Recent work also includes: Searches/limits for M1 transitions ( b ) First observation of a (1D) state (first new (bb) state in 20 years!) Measurements of new hadronic transitions (e.g., b1,2 (2P) (1S)) Searches for anomalous couplings Many other interesting topics are in the pipeline Exclusive 2 and 4 transitions in (3S) decays New measurements of ee for (1S), (2S), (3S) (1S,2S,3S) Open Charm (1S) , K*K, etc (“ puzzle”) Searches for LFV …
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Backup Slides
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The Physics The (1S)- (3S) resonances are the QCD analogy of positronium - bb are bound by the QCD potential: e.g. V(r)= – 4/3 s /r + kr Large b quark mass (v/c) 2 ~ 0.1 non-relativistic to 0 th order (In some models, relativistic corrections added to non-relativistic predictions) In much the same way that positronium allowed for a greater understanding of QED, the masses, splittings between states and the transition rates provide input into understanding QCD. Tests of lattice QCD Important for flavor physics ! Test of effective theories, such as QCD potential models Coulomb-like behavior from 1-g exchange Long distance behavior, confining k~1 GeV/fm
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Electric Dipole Transitions After normalizing out the (2J+1)E 3 between different J’s, we obtain: b (2P): (J=2) / (J=1) (J=0) / (J=1) (J=0) / (J=2) 1.00 0.01 0.05 0.76 0.02 0.07 0.76 0.02 0.09 b (1P): (J=2) / (J=1) (J=0) / (J=1) (J=0) / (J=2) 1.01 0.02 0.08 0.82 0.02 0.06 0.81 0.02 0.11 c (1P): (J=2) / (J=1) (J=0) / (J=1) (J=0) / (J=2) 1.50 0.02 0.05 0.86 0.01 0.06 0.59 0.01 0.05 In the non-relativistic limit, the E1 matrix element is spin independent. In NR bb system, (v/c) 2 ~ 0.1 expect ratios ~ 1 NR corrections O (<20%) for J=0 Also shown are (cc), which show sizeable differences (v/c) 2 ~0.3; mixing between 2 3 S 1 and 1 3 D 1 states may also contribute. Comparison with various models E1 = B (n i S n f P) tot ( (nS)) Using: Uses new CLEO tot values We can extract Relativistic corrections needed for (cc) In (bb) system, NR calculations in reasonable agreement with data. o = predictions (non-relativistic) ▲ = spin-averaged predictions (relativistic) time
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Spin-Orbit & Tensor Interactions Responsible for splitting the P states 3 P J Can express: M J=2 = M cog + a LS - 0.4a T M J=1 = M cog - a LS + 2a T M J=0 = M cog - 2a LS - 4a T where Spin-Orbit Coeff. Tensor Coeff. V 0 = static potential; V 2,3 = spin-dependent potentials (both model-dependent) Data on mass-splittings can be used to extract a LS and a T, Experimentally, the mass splittings are most precisely determined using CLEO3CLEO2 r (1P) 0.57 0.01 0.010.54 0.02 0.02 r (2P) 0.58 0.01 0.010.57 0.01 0.01 Our results indicate that there is no difference between the different radial excitations of the P waves in (bb) system.
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Search for b in (3S) b (1S) and (2S) b (1S) (2S) b (1S) (3S) b (1S) b (2P J ) (1S) (2S) Data b (1P J ) (1S) Hindered (n i n f ) M1 transition suppressed by 1/m b 2 Large differences among models (3S) Data (3S) b (2S) (2S) b (1S) (3S) b (1S)
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CUSBII (PRD46,1928(1992)) vs CLEOIII £ (3S) ~200/pb £ (3S) ~1300/pb ~10% (poor segmentation of calorimeter) ~60% Also it seems that they had worse energy resolution. We are very surprised that they claimed comparable accuracy to ours. (3S) b (2P J )
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e + e - J/ +X using on Y(4S) Data, p J/ >2 GeV
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Y(1S) & Y(4S) Overlayed
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