Recent CLEO results on spectroscopy

Tomasz Skwarnicki CLEO Results Excited QCD 2010 T. Skwarnicki 2 Onia Number of FORCES states below System Ground triplet state 1 3S dissociation 1 energy (v/c) 2 binding decay 3 Name Γ (MeV) Mass (GeV) n S1 all POSITRONIUM EM EM e+e− Ortho- 5 10 −15 0.001 ~0.0 2 8

QUARKONIUM S uu,dd ρ 150.00 0.8 ~1.0 0 0 T S ss φ 4.40 1.0 ~0.8 “1” “2” T cc 0.09 3.1 ~0.25 R O ψ 2 8 E O N M bb ° 0.05 9.5 ~0.08 3 30 N G G Toponium weak tt (3000.0) (360.) <0.01 0 0 is not a lab for QCD Consequences of large mQ: • velocities of constituents are small v Expansion parameters • strong coupling constant in annihilation and production is small αs This opens avenues for effective theories of strong interactions: • purely phenomenological potential models • more recently NRQCD and much improved QCD on Lattice CLEO Results Excited QCD 2010 T. Skwarnicki 3 Content of this talk • Report on two recent measurements with the CLEO-III and CLEO-c detectors:

– Measurement of the ηb(1S) mass and the branching fraction for ϒ(3S) →γ η b(1S) [arXiv:0909.5474] – Higher-order multipole amplitudes in charmonium radiative transitions [Phys.Rev.D80:112003,2009] .

• CLEO-c detector (cc data): e+ – Charged particle detection (1T): σp/p=0.6% at 1 GeV – Photon detection: σE/E=4.8% at 100 MeV, 2.2% at 1 GeV – ID: dE/dX+RICH (fake rates at a few % level) • CLEO-III detector (bb data): e- – The same detector except for inner vertex detector (silicon) and magnetic field (1.5T) CLEO Results Excited QCD 2010 T. Skwarnicki  4 S S Hyperfine splitting 1⋅ 2 L S1 2S+1 r    n L J n J = L+ S

S2  S 

S=S1 +S 2 • Expected to be significant only for S states ( L=0 ) • Hyperfine splitting of the ground state of bb ( n=1 ) a good place to test lattice QCD calculations:

3 1 ∆Mhf (1S)bb = M( 1 S1) − M( 1 S0) = M( ϒϒϒ) − M( ηηηb) • Only recently measured experimentally thanks to

the first observation of ηηηb by BaBar CLEO Results Excited QCD 2010 T. Skwarnicki 5

First observation of ηηηb by BaBar BaBar PRL 101, 071801, 2008 BaBar π 0 #ϒ(3S) =109M b E1 k g

6 χbJ (2P) →γ ϒ(1S)

Hindered ISR M1 e+e- → E1 γ ϒ(1S) γ ηb γ

g g g g g ϒϒϒ(3S) →→→γ→γ ηηηb (…π0..)

γ γ • Statistical significance >10 σ (Assuming Γ(ηb)=10 MeV ) CLEO Results Excited QCD 2010 T. Skwarnicki 6 Confirmation from the CLEO data? • The CLEO ϒϒϒ(3S) data samples is ~18 times smaller than the BaBar’s

• We published the upper limit on BR( ϒ(3S) →γη b) < 4.3x10 -4 (90% C.L.) in 2005 [vs BaBar (4.8 ±0.5 ± 0.6)x10 -4] , but: – We did not include the ISR peak in the background fit which biased the BR down;

– We assumed Γ(ηηηb)=0, while 4-20 MeV is predicted (not completely negligible compared to the resolution). – We did not use continuum background suppression cuts, which BaBar proved to be beneficial for this channel (our analysis was optimized to lower energy E1 transitions where continuum backgrounds were insignificant) • Today present re-analysis of the CLEO data, optimized for ϒϒϒ(3S) →→→γ→γ ηηηb sensitivity CLEO Results Excited QCD 2010 T. Skwarnicki 7 Improved thrust axis analysis

Continuum bkg e+e- →→→ qq

θθθ

Thrust axis γγγ

ϒϒϒ(3S) →→→γ→γ ηηηb θθθ

Thrust axis γγγ

• BaBar used |cos θ|<0.7 • We split <0.7 into 2 bins (the main improvement) and keep >0.7 data • We perform simultaneous fit to all 3 photon spectra CLEO Results Excited QCD 2010 T. Skwarnicki 8 CLEO search for ϒϒϒ(3S) →→→γ→γ ηηη ISR b e+e- → ϒϒϒ(3S) →→→γ→γ ηηηb χbJ (2P) →γ ϒ(1S) γ ϒ(1S) The smooth background

and χbJ (2P) →γ ϒ(1S) subtracted.

• Statistical significance ~4 σ

(Assuming Γ(ηb)=10 MeV ) CLEO Results Excited QCD 2010 T. Skwarnicki 9

CLEO search for ϒϒϒ(2S) →→→γ→γ ηηηb ISR e+e- → ϒϒϒ(2S) →→→γ→γ ηηηb χbJ (1P) →γ ϒ(1S) γ ϒ(1S) The smooth background and χbJ (2P) →γ ϒ(1S) subtracted.

• No signal detected (much higher resonant backgrounds) • BaBar detected ~3.5 σ signal in ~10 times more data

(Assuming Γ(ηb)=10 MeV ) CLEO Results Excited QCD 2010 T. Skwarnicki 10 CLEO vs BaBar vs theory

(Assuming Γ(ηb)=10 MeV )

3.9

Unquenched

• The experimental results for hyperfine mass splitting agree with the unquenched lattice QCD calculations • BaBar has the best measurements • Significance of the CLEO measurement is in independent confirmation of the BaBar results CLEO Results Excited QCD 2010 T. Skwarnicki 11 Higher-order mutipole amplitudes in charmonium radiative transitions • Wavelength of the radiated photon large compared to the 23S 1 radiating system, thus lowest 13P 3 2 multipole amplitude 1 P1 3 dominates: E1 1 P0 • Allowed higher order mutipoles: 3 1 S1 3 – For 1 P1: M2 3 – For 1 P2: M2, E3 l+ l− • To the first order in Eγ/m c , a fraction of M2 amplitude is expected to be: • Denote these fractions as: 3 J 1 P1 – b2 for ψ(2S) →γ χ cJ (1P J) J 3 – a2 for χcJ (1P J) → γJ/ ψ(1S) 1 P2

κc – anomalous magnetic moment of c-quark (expect κc=0) CLEO Results Excited QCD 2010 T. Skwarnicki 12 Previous measurements

?

? The ratios are independent ? of m c , κc (in the 1st order)

• Inconsistencies between data and theory CLEO Results Excited QCD 2010 T. Skwarnicki 13 CLEOc data • Select γγµ +µ− or γγ e+e- events. Backgrounds are small and under control. The χc1 and χc2 are well separated.

40k events 20k events

• By an order of magnitude larger statistics than in the previous experiments. CLEO Results Excited QCD 2010 T. Skwarnicki 14 CLEOc results (assuming no E3)

Presence of quadrupole amplitudes established at 11.1 σ (6.2 σ) for J=1 (2).

• Good agreement with the theoretical predictions (mc=1.5 GeV, κc=0) Allowing electric octupole (E3) amplitude for J=2 data: J=2 -3 J=2 -3 a3 = (1.7 ± 1.4 ± 0.3) 10 b3 = ( −0.8 ± 1.2 ± 0.2) 10 J=2 J=2 (the results for a 2 , b 2 change within the errors) CLEO Results Excited QCD 2010 T. Skwarnicki 15 CLEOc results

• The inconsistencies with the theory has been resolved

κc = −0.123 ± 0.088 ± 0.034 ± 0.175 (last error due to m c=1.5 ± 0.3 GeV) CLEO Results Excited QCD 2010 T. Skwarnicki 16 Conclusions

• BaBar’s observation of the ϒϒϒ(3S) →→→γ→γ ηηηb confirmed by the CLEO data: – The experimental results for hyperfine mass splitting agree with the lattice QCD calculations • Admixture of the magnetic quadrupole amplitude 3 to predominantly electric dipole transitions 2 S1 3 3 → 1 P1,2 → 1 S1 in charmonium well established by the CLEOc data: – No inconsistencies with the expectations, unlike in the previous experiments – No evidence for anomalous magnetic moment of c- quark