Results on Charmonium and Bottomonium

Results on Charmonium and Bottomonium Tom Browder (University of Hawaii)

Will cover results from BESII, CLEO(-c), BaBar and Belle

Thanks: I have borrowed from talks by Pedlar, Shepard, Olsen, Muramatsu, Mussa, CZ Yuan, Skwarnicki. I have benefitted from correspondence with Soren Prell and others.

Apologies: Not an expert but a backup speaker. Can only cover a small subset of interesting results in the available time.

Charmonium

r

mesons formed from c- and c-quarks

c-quarks are heavy: mc ~ 1.5 GeV 2mp

velocities small: v/c~1/4 (for b b, v/c ~0.1)

non-relativistic QM applies

c c

_

ErVmr

)(2

22

What is V(r) ??

S. Olsen

“Cornell” potential

~0.1 fm

G.S.Bali hep-ph/0010032

“confining”large distance

component

slope~1GeV/fm

1/r “coulombic”short distance

component

c cr

V(r)

2 parameters:slope & intercept

Charmonium spectrum

1-- Charmonium states

J/’

D-meson + anti-D meson mass threshold

”

“narrow”(~100KeV)

e+

e-

Directly accessible via e+e- annihilation

(e+e-hadrons)

“narrow”(~300KeV)“wide”(~25 MeV) ” DD decay

channel is openDD)25MeV

(4

040)

(4

160)

(4

415)

Important BES contribution to R

(3770), (4040), (4160), (4415)In 1998 and 1999, BES scanned 91 energy pointsbetween 2 and 5 GeV to determine R.

Phys. Rev. Lett. 84, 594 (2000) and 88, 101802, (2002).

Results from the new R analysis (2007)

hep-ex: 0705.4500

Resonance parameters (PLB660, 315 (2008))

BESII : J/ 2001 – 58 M; CLEO-c: (2S) 2006 -27 M

0

10

20

30

40

50

60

MarkIII DM2 BESI BESII

CLEO-c has CsI(Tl) crystals, BESII does not but BESIII will .

Current J/ and (2S) Samples (×106)Note: B( ψ(2S)->+-J/ψ)~32% one can tag J/ψ events very cleanly and efficiently.

Inclusive photon signal for ψ’γ ηc

B(ψ(2S)->γ ηc (1S)) = (4.32+-0.16+-0.60)*10^-3B(J/ ψ->γ ηc (1S)) = (1.98+-0.09+-0.30)%

B(J/ ψ->γ ηc (1S))/B( ψ(2S)->γ ηc (1S)) = 4.59+-0.23+-0.64.

arXiv:0805.0252

Renormalize ηc

BF scale

Signal for J/ψγηc

Discrepancy between ηc properties (especially

widths) in different processes is unresolved.

P-wave states Gamma energy spectrum from ’ X decays

Gaiser et al (Crystal Ball) PRD 34 711

accessible via E1 transitions from ’

23S1 (’)13P2 (c2) 17 keV

23S1 (’)13P1 (c1) 24 keV

23S1 (’)13P0 (c0) 24 keV

13P2 (c2) 13S1(J/) 420 keV

13P1 (c1) 13S1(J/) 290 keV

13P0 (c0) 13S1(J/) 120 keV

E1 Transition Partial width

Calculable from”1st prin

ciples”

Good agreement with

measurements

Hadronic transitions

(’J/) 70 keV“allowed”

(”J/) 50 keV“allowed”

(’J/) 5 keVallowed

(’J/) 0.3 keVisospin violating

“reasonable” agreement between

measurement & th

eory

c.f. Kuang & Yan PRD 41 155

ψ0 hc0γ ηc

CLEO 2005 +2007 update Belle 2002

Charmonium table below D Dbar threshold is complete

The hcand ηc(2S) have been observed

Recent results on non-exotic charmonia

13D1 13P1 11P0

seen by CLEO, Phys.Rev.D74:031106,2006.

(meas) = 75 18 keV(theor) ~59-77 keV

11P1 (hc) found by CLEOhep-ex/0508037properties as expected

23P2 found by Bellehep-ex/0507033properties as expected

21S0 (ηc(2S)) found by BelleS.K.Choi et al PRL 89 102001

properties as expected

The old “missing states” (hc and ηc(2S)) have now been observed

May 1, 2003

The potential model for (ccbar) charmonium mesons is robust and reliable.

Declare victory

K*K

ρπ

MARK-II

Old unsolved mystery

Problems with strong decays of charmonium

X-H Mo et al, review in hep-ph/06011214 (>10 proposals)

RosnerOne possible explanation

W. S Hou’s idea, glueball-J/ψ mixing, seems to be ruled out

’ Baryon Anti-baryon OK First measurements by BESI, remeasure BR with BESII

data sample.

pp-bar

ΛΛ-bar

ΣΣ-bar

’ pp

’ ΛΛ pπ-pπ+

’ Σ0 Σ0

pπ-pπ+ ΞΞ-bar’ Ξ- Ξ+

p2π-p2π+

Consistent with “12% rule”.

Bottomonium Data Samples

~14.4fb-1 on the Y(2S)Belle 2.9 fb-1 (2006) , 11 M Y(3S) BaBar, 30.3 fb-1, ~120 M Y(3S)

Bottomonium: Some mysteries in strong decays

“QCD Multipole Expansion”

( )mS ( )nS

What is special about the case m-n > 1 ?

'

Most famous ancient mystery (1994-2000)

Possible Theoretical Explanations:

High statistics data and sophisticated analysis may provide some clues (CLEO)

The matrix element for Υ(mS)Υ(nS)

In the above, ε, ε’ are the polarization vectors of the Υ(nS), Υ(mS)

q1, q2 are the pion 4-vectors while E1, E2 are their energies in the Υ rest frames. q2 is the invariant mass of the two pions

The amplitudes A, B could be complex

CLEO High Statistics Analysis of di-pion matrix element

M, θX

CLEO High Statistics Analysis of di-pion matrix element

A, B are complex. B was previously neglected

C is consistent with zero (spin flip and breakdown of QCD multipole expansion not present). PRD 76, 072001

(2006)

Belle dataBaBar data

PRD 071103 (R) 2007

Recent data for Υ(4S)Υ(1S,2S) + - Non-B Bbar decay

PRL 96 (2006) 232001

CLEO’s first evidence for (2S)(1S) η

4( (2 ) (1 ) ) (2.31 0.74) 10BF S S

0 4( (2 ) (1 ) ) 1.6 10BF S S One candidate is found,

4.6σ

Expect this is 16% of the η mode

preliminary

BaBar discovers Υ(4S)(1S)η

These are examples of non-B Bbar decays that have been observed by BaBar and Belle.

3( (2 ) (1 ) )(1.3 0.5) 10

( (2 ) (1 ) )

S S

S S

preliminary

Could related transitions provide a way to discover the elusive hb or ηb ?

(3 ) (2 ) ( )b bS P (Voloshin, Mod. Phys. Lett. A 19, 2895 (2004))

0(3 ) ,b b bS h h (Godfrey, Rosner, PRD66, 014012 (2002) like CLEO’s hc search )

Two suggestions:

Where is the ground state bottomonium ηb ?

Which Upsilon(nS) is best ? Inclusive or exclusive ? What are the

hadronic modes of the ηb ?

Tests theory and is the highest priority of the quarkonium working group (QWG)

Direct M1 transitions

Second mystery or big problem in the field:

Where is the ηb, the ground state bottomonium state ?

Total cross-section

Search for a Y(4260) analogue in the bottomonium sector

Y(4260) → J/ + - Is there a corresponding bb state b → (1S) + - ?

Resonant structure is rather complicated above BB threshold.

E.g. Y(10860) is commonly assumed to be a radially excited 1-- b b bound state a.k.a the Y(5S), but we do not really know that.

World wide Y(10860) data:

1985 CLEO 0.1/fb

2003 CLEO III 0.43/fb

2005 Belle 1.9/fb

2006 Belle 21.7/fb

“Searching for the bottom counterparts of X(3872) and Y(4260) via + -Υ(1S)”,

Wei-Shu Hou, PR D74, 017504 (2006) → theory inspiration

(experimental work by Kai-Feng Chen and Anatoly Sokolov)

Collected mainly for Bs physics, ≈105 Bs / fb

Use this data to measure + - Υ(1,2,3S) production at the (10860)

Anomalous (1,2,3S) +-, (1S) +- cross sections at (5S)

(10860) decay or decay of new overlapping state Yb? Energy scan (7.9 / fb) around (10860) : compare S)

and total hadronic cross sections. Results will be ready soon.

(10860)

(2S)

(1S)

Final state

Initial state

(3S)

(2S)

(3S)

(1S)

(10860)

tot MeV (1S)+- keV

(2S) 0.032 6

(3S) 0.020 0.9

(4S) 20.5 1.8

(10860) 110 590

PRL 100, 112001, 21.7 fb-

1

Phase space, Cahn-Brown model (B=0)

What about the dipion mass distributions for the Y(10860) ? (the state formerly known as the “Υ(5S)”)

There are hints of a low mass structure in a) and b) but statistics are low.

Bottomonium: New Physics Potential

Suppose those precision electroweak fits are taken literally, MH~76±30 GeV.

Suppose nMSSM is correct, then there is a H and another light Higgs particle a1 (m(a1) <m(b)). Can avoid LEP limits and still have MH~100 GeV. (R. Dermisek, J. Gunion, B. McElrath)

The dominant decay mode might be:

1 1 ( )( )H a a

Difficult at a hadron collider. But could find the light Higgs (a1) in bottomonium at B or Super B Factories.

Bottomonium: New Physics Potential (cont’d)

One motivation for BaBar’s 30 fb-1 Y(3S) run.

Hunting dark matter or light Higgs in Υ(nS) decaysHigh precision check of lepton universality in dilepton decays Light Higgs signature

Can also search for the HYPER-CP particle using decays to aμ+ μ-

Expect compelling results on bottomonium from BaBar (and perhaps Belle) in the near future.

BaBar’s final runKirkby

More New Results (but not enough time to cover)

New Measurements of Upsilon(3S) Branching Fractions (CLEO)

New Measurements of Upsilon(3S) Branching Fractions (CLEO)

It looks like there may be a bbversion of the Y(4260)

lurking around the (5S)

If there are bb versions of the XYZ’s, why not ss versions as well?

W.-S. Hou PRD 74, 017504 (2007)

1-- Ys states around 2 GeV?Y(2175)f0(980)

from BaBar (confirmed by BESII)

e+e- f0(980)@ Ecm ~10.6 GeV

confirmed by BESII

M(f0(980) GeV

M.Ablikim et al (BES)PRL 100, 102003

(2008)

Backup Slides

The new 2007 improved results

Comparison of the updated R value and the old results in Phys. Rev. Lett. 88 (2002) 101802

Differences in R values are due to the updated resonant parameters and initial state radiative correction factor (1+obs).

preliminary

hep-ex: 0705.4500

0

0.5

1

1.5

2

2.5

3

3.5

4

BES

CLEO

’ Baryon antibaryon OK

BESII – CLEOccomparison

pp-bar ΛΛ-bar ΣΣ-bar ΞΞ-bar

Consistent with SU(3) symmetry.

Reduced Branching Ratios

R = Br/(π p* /s½), p* is baryonmomentum.

R’s same under SU(3) symmetry.

BES

Phys. Lett. B648, 149 (2007)

Belle:((5S)(nS))

2S

3S4S

(4S) (1S) +

(4S)(1S)477 fb-1 from Belle

44±

8 e

vts

“(5S)”(1S)23.6 fb-1 from Belle

(1/20 times the data &

~1/10th the crosssection)

325±

20

evts

!

8 times as many events!

Belle 0710.2577

K.F. Chen et al (Belle) PRL 100, 112001 (2008)

(2 weeks ago)

is Huge!!

Partial Widths

N.B. Resonance cross section 0.302 ± 0.015 nb at 10.87 GeV PRD 98, 052001 (2007) [Belle]

Cf (2S) (1S) ~ 6 keV (3S) 0.9 keV (4S) 1.8 keV

Assume “(5S)” = (5S)PDG value taken for (nS) properties

>100 times bigger!!

Where is the ground state bottomonium ηb ?

Which Upsilon(nS) is best ? Inclusive or exclusive ? What are the

hadronic modes of the ηb ?

Tests theory and is the highest priority of the quarkonium working group (QWG)