Heavy flavor, Quarkonium Production and Decay

1
Heavy flavor,Quarkonium Production and Decay

• Xiaoyan SHEN
• Institute of High Energy Physics, CAS
• shenxy_at_ihep.ac.cn
• Lepton-Photon 2005
• June 30 July 5, 2005, Uppsala, Sweden

2
Introduction

• QCD has been tested extensively at the high
  momentum transfer by lots of high precision
  experiments.
• At low energy, it is difficult to be tested due
  to non-perturbative nature

Probe QCD from various directions
QQ (QQ) production, spectra and decays qq
and qqq spectra non-qq and non qqq states
3
Heavy Quarkonia Spectra
Rich spectroscopy, various production schemes,
interesting decay scenarios
4

• Bound states of qq, the QCD equivalents of
  positronium (ee-) in QED
• Simplest strongly interacting systems
• Less relativistic for cc, more non-relativistic
  for bb
• large MQ
• Small velocities of constituents
• Small ?s in annihilation and production

expansion parameters v,?s

• This opens avenues for effective theories of
  strong interactions
• purely phenomenological potential models
• more recently NRQCD and much improved Lattice
  QCD

• Properties of these bound states, and their
• decays and productions are good labs. for QCD
• in both perturbative and non-perturbative
  regimes.

5
outline

• New observed particles since last year
• X(1835), X(3940), Y(3940), Y(4260)
• Heavy (flavor) quarkonia production
• Heavy hadron spectroscopy
• ?c, hc, Bc, X(3872)
• Selected topics from quarkonium decays
• Summary

6
New Observation of X(1835) in
at BESII
7
Observation of an anomalous enhancement near the
threshold of mass spectrum at BES II
J/y?gpp
BES II
acceptance weighted BW
3 5 -10 -25
M1859 MeV/c2 G lt 30 MeV/c2 (90 CL)
X(1860)
c2/dof56/56
0
0.1
0.2
0.3
3-body phase space
M(pp)-2mp (GeV)
acceptance
8
Study of B ? pp K at BaBar and Belle
BaBar 210 fb-1
Belle
BES II
X(1860)

• The pp threshold enhancement
• observed in J/? decay is
• different from the enhancements
• observed by Belle and BaBar
• in B decay.
• The one in B decay can be
• explained by fragmentation.

9
X(1860) from BES has large BR to pp

• BES measured
• For a 0- meson
• So we would have
  
• (This BR to pp might be the largest among all
  PDG particles)

Considering that decaying into pp is only
from the tail of X(1860) and the phase space is
very small, such a BR indicates X(1860) has
large coupling to pp !
10
pp bound state (baryonium)?
There is lots lots of literature about this
possibility

• E. Fermi, C.N. Yang, Phys. Rev. 76, 1739 (1949)
• I.S. Sharpiro, Phys. Rept. 35, 129 (1978)
• C.B. Dover, M. Goldhaber, PRD 15, 1997 (1977)
• Datta, P.J. ODonnell, PLB 567, 273 (2003)
• M.L. Yan et al., hep-ph/0405087
• B. Loiseau et al., hep-ph/0411218

deuteron
baryonium
attractive nuclear force
attractive force?

n

-
loosely bound 3-q 3-q color singlets with Md
2mp- e
loosely bound 3-q 3-q color singlets with Mb
2mp-d ?
Observations of this structure in other decay
modes are desirable.
11
BES X(1835) in
X(1835) 5.1 ?
X(1835) 6.0 ?
BES II Preliminary
12
Combine two channels
7.7?
Statistical Significance 7.7 ?
X(1835)
BESII Preliminary
BESII Preliminary
13
X(1835) could be the same structure as X(1860)
indicated by pp mass threshold enhancement

• X(1835) mass is consistent with the mass of the
  S-wave resonance X(1860) indicated by the
  pp mass threshold enhancement.
• Its width is 1.9? higher than the upper limit
  of the width obtained from pp mass threshold
  enhancement.
• On the other hand, if the FSI effect is included
  in the fit of the pp mass spectrum, the width of
  the resonance near pp mass threshold will become
  larger.

14
Fit to J/? ? ?pp including FSI

M 1830.6 ? 6.7 MeV ? 0 ? 93 MeV
Include FSI curve from A.Sirbirtsev et
al.(hep-ph/ 0411386) in the fit (I0)
BES II Preliminary
In good agreement with X(1835)
15

• X(1835) could be the same structure as pp mass
  threshold enhancement.
• It is likely to be a pp bound state since it
  dominantly decays to pp when its mass is above pp
  mass threshold.
• ??? mode is expected to be the most favorable
  decay mode for a pp bound state below pp mass
  threshold

G.J. Ding and M.L. Yan, hep-ph/0502127
16
Y(3940) - near ?J/? threshold enhancementin B?K
?J/? at Belle
If it is treated as a S-wave BW
PRL 94 (2005) 182002
M 3943 ? 11 ? 13 MeV/c2 ? 87 ? 22 ? 26 MeV/c2
253 fb-1
?2/d.o.f. 115/11
?2/d.o.f. 15.6/8 stat. sig. 8.1?

• above DD threshold
• not found in DD or
• DD final states

a ccg hybrid charmonium?
17
X(3940) in ee- ? J/? cc at Belle
X(3940)
?c(2S)
350 fb-1
M (3943 ? 6? 6) MeV/c2 ? lt 52 MeV/c2 (90 C.
L.) Stat. sig. 5.0 ?
?c(1S)
?c0
above DD and DD thresholds
Mrecoil(J/?)
a new charmonium state
18
X(3940) in ee- ? J/? cc at Belle
Search for X(3940) ? DD and DD
ee-?J/? DD
ee-?J/? DD
3.3?
5.1?
ee-?J/? DD
Mrecoil(J/?)D
D sideband
Dominant decay of X(3940)
19
Whether X(3940) and Y(3940) are same?
Search for X(3940) ? ? J/?
? sideband

• Reconstruct the ? and one
• J/? from ee- ? ? J/? J/?
• look for X(3940) in M(? J/?)
• no evidence of X(3940)?? J/?

20
New observation of Y(4260) at BaBar
211 fb-1 data collected at srqt(s) 10.58 GeV
Y(4260)
?(2S)
Y(4260)
from J/? sideband
11802?110 ?(2S) events 125?23 Y(4260) events
21

• ISR events with KK-J/? spectrum show a
• featureless mass spectrum exclude
• the possibility of K and ? misidentification.
• ISR events with a ??-J/? plus one or more
• additional pions show no structure that
• could feed down to produce Y(4260) in
• ??-J/? mass spectrum.
• Y(4260) not from two-photon events
• no substantial improvement obtained by
• including ?(4040), ?(4160) or ?(4415) in
• the fits

22

• A single relativistic BW (multiplied by PS
  factor and
• convoluted with Cauchy resolution
  function) 2nd order
• polynomial are used in the fit.

11802?110 ?(2S) events 125?23 Y(4260) events
? 8 ?

• if the observed signal is due to two interfering
  
• resonances
• 1st resonance M ? 4260 MeV/c2, ? ? 50 MeV
• 2nd resonance M ? 4330 MeV/c2, ? narrow

Signify the presence of 1-- state containing
hidden charm.
23
Heavy (flavor) quarkonium production
24
Many New b,c-Production Results
b Production b Production b Production b Production
CDF CDF b-Hadron inclusive cross-section in Run II using Hb?J/?X
Hera-B Hera-B b b-bar production cross-section in pN collisions
H1 H1 Charm and Beauty photoproduction
ZEUS ZEUS Beauty photoproduction using muon dijet events
ZEUS, H1 ZEUS, H1 Beauty production at HERA
H1 H1 Inclusive beauty production at low and high Q2
ZEUS ZEUS Beauty production in DIS
c Production c Production c Production c Production
ZEUS charm production cross-section in DIS and photoproduction (HERA, HERAII) charm production cross-section in DIS and photoproduction (HERA, HERAII)
ZEUS, H1 Inelastic J/psi production at HERA Inelastic J/psi production at HERA
H1 Inclusive charm cross section at low and high Q2 Inclusive charm cross section at low and high Q2
H1 D production in DIS D production in DIS
H1 Inclusive production of D, D0, D?, Ds in DIS Inclusive production of D, D0, D?, Ds in DIS
ZEUS The production of D, D0, D?, Ds and ?c in ?p collision The production of D, D0, D?, Ds and ?c in ?p collision
ZEUS, H1 Photoproduction of D Photoproduction of D
ZEUS Inclusive jet cross sections and dijet correlations in D photoproduction Inclusive jet cross sections and dijet correlations in D photoproduction
ZEUS D meson production in DIS ep at low Q2 D meson production in DIS ep at low Q2
25
NRQCD successful in describing

• Inclusive P-wave quarkonium decays
• Quarkonium production at Tevatron
• ?? ? J/? X at LEP
• Quarkonium production in DIS at HERA

NRQCD problematic in describing

• Quarkonium polarization at the Tevatron
• Inelastic quarkonium photoproduction
• at HERA
• Double cc production at B factories

26
Inelastic J/? production in DIS at HERA
ZEUS (1996-2000)
109 pb-1
J/?

• Compared to theoretical predictions
• within NRQCD
• (CSM COM) (COM spoils the agreement).
• kT-factorization approach

27
Charm and Beauty photoproduction at HERA using
D? Correlations
71.2 pb-1 data at sqrt(s) 320 GeV 17.8 pb-1 data
at sqrt(s) 300 GeV
charm Cross section(pb)
Data NLO pQCD 250?57?40 286159-59
beauty
Data NLO pQCD 206?53?35 5214-9
Differential ? shape in agreement. High order
corrections needed.
big discrepancy for beauty total ?.
28
Double charmonium production

• One of the most challenging open problems in
  heavy quarkonium is
• the large discrepancy of the double charmonium
  production cross sections measured in ee-
  annihilation at B factories and the theoretical
  calculations from NRQCD.

29
Double charmonium production at Belle and BaBar
ee- ? J/? cc
(cc)res ?Born?Bgt2(fb) ?Born?Bgt0(fb)
?c(1S) 25.6?2.8?3.4 16.3?4.6?3.9
J/? lt9.1 lt16.9
?c0 6.4?1.7?1.0 12.5?3.8?3.1
?c1 ?c2 lt5.3 lt8.6
?c(2S) 16.5?3.0?2.4 16.0?5.1?3.8
?(2S) lt13.3 lt5.2
155 fb-1
hep-ex/0412041
?c(1S)
?c(2S)
(cc)res ?Born?Bgt2(fb)
?c(1S) 17.6?2.81.5-2.1
?c0 10.3?2.51.4-1.8
?c(2S) 16.4?3.72.4-3.0
?c(1P)
124.4 fb-1
30
(No Transcript)
31
Several hypotheses are suggested to solve the
problems

• Processes proceeding via two virtual photons may
  be important (J/? J/?)
• (G.T. Bodwin, J. Lee and E. Braaten, PRL 90
  (2003)162001)
• The final state contains a charmonium state and a
  M3 GeV/c2 glueball
• (S.J. Brodsky, A.S. Goldhaber and J. Lee,
  PRL 91 (2003)112001)
• (Dulat, Hagiwara Lin hep-ph/0402230)

• Belles updated analysis shows (PRD 70 (2004)
  071102)
• ee-???? J/? J/? contamination is small
• no evidence for ee- ? J/? glueball

32

• Treat charm quark as a light quark, use
  light-cone
• wave function to parameterize non-perturbative
• effects related to the inner structure of
• charmonium.
• (J.P. Ma and Z.G. Si, PRD 70 (2004)074007)
• (A.E. Bondar and V.L. Chernyak,
  hep-ph/0412335)
• But the enhanced cross section is sensitive
  to the specific form
• of quark distribution.
• Calculate the NLO QCD corrections with NRQCD
• factorization formalism. The ratio of NLO/LO
• can reach 1.8. Reduce the large discrepancy.
• (Y.J. Zhang, Y.J. Gao and K.T. Chao,
  hep-ph/0506076)
• But the discrepancy still exists.

33
Heavy Hadron Spectroscopy
34
(Re)discovery of ?c(2S)

• Observation of ?c(2S), measurement of
• M(?(2S)-?c(2S)) provide useful information
  about
• the spin-spin part of the charmonium potential
• Crystal Balls possible evidence of ?c(2S) was
  not
• confirmed by other exps. (M 3594?5 MeV/c2).
• Non-observation by E760 and E835
• Belle first observed ?c(2S) from B? K(KsK?-)
  and
• ee- ? J/? X
• ?c(2S) was then confirmed by CLEO and BaBar in

?? ? KsK?
35
?c(2S) current status
gg? KsKp-
gg? KsKp-

ee-? J/y X
B? K(KsKp-)
?
y(2S) ?gX
C. Ball

• Heavy quark potential model
• predictions 42 103 MeV/c2
• Quenched LQCD 40 74 MeV/c2
• K. Okamoto PRD65 (2002)094508

MAVG 3637.74.4 MeV/c2
Crystal Ball meas. excluded
36
hc (1P1) state

• R704 at CERN observed a cluster of 5 events in an
  exclusive scan for pp ? J/? X.
• M 3525.4?0.8 MeV/c2
• (PLB 171 (1986) 135)
• E760 at FNAL observed an enhancement in pp??0J/?
• M 3526.2?0.2?0.2 MeV/c2
• no enhancement in pp ? ?? J/?
• (PRL 69 (1992) 2337)

37
observation of hc (1P1) state in ?(2S) decay by
CLEO
CLEO
With Inclusive ?c decay
With exclusive ?c decay
3.08M ?(2S)
hc
150?40 events stat. sig. 3.8?
M(?0 recoil) (GeV)
inclusive exclusive
Counts Significance M(hc)(MeV/c2) Br?Bh(?10-4) 150?40 3.8? 3524.9?0.7?0.4 3.5?1.0?0.7 17.5?4.5 6.1? 3523.6?0.9?0.5 5.3?1.5?1.0
CLEO hep-ex/0505073
38
E835 preliminary results on hc (1P1) state
by a scan of pp annihilation cross section for
exclusive final states at different Ecm
pp ?hc ? ??c ? ???
pp ? ?0J/? ? ee-??

• E835-I 140pb-1
• ? E835-II 110pb-1

preliminary
preliminary

• E835-I 140pb-1
• ? E835-II 110pb-1

No significant excess found. Disprove E760 hc
evidence
Mhc3525.8?0.2?0.2 MeV
hep-ex/0410085
39
Search for hc (1P1) in B?hc K at Belle
No hc (1P1) observed.
Moriond05
40
Bc (cb) ground state (1S0, JP0-)
Bc mass
(I.F. Allison et al, PRL 94 172001)
(Y.Q. Chen Y.P. Kuang, PRD 46, 1165 Eichten
C.Quigg, PRD 49, 5845.)
First observed by CDFI in 1.8TeV pp collision
Bc ? J/y(mm-) m n
110pb-1
110pb-1
4.8 ?
(CDF, PRL 81(1998)2432)
41
hep-ex/0505076
ICHEP04
Evidence for exclusive Bc? ? J/? ??
Bc? ? J/y m??? X


360pb-1
210pb-1
18.9 ? 5.7 signal events 0.27 prob.
first evidence of a fully reconstructed decay
mode of Bc
42
X(3872)
43

• First observed by Belle in B ? K(J/? ??-)
• Then confirmed by CDF, D0 and BaBar

Belle
X(3872)
304M Bs
?
?
X(3872)
Events/10 MeV
220 pb-1
PRL 91 (2003) 262001
PRL 93 (2004) 072001
X(3872)
BaBar
230 pb-1
PRD 71 (2005) 071103
PRL 93 (2004) 162002
44
X(3872) in B0 and B decays at BaBar
211 fb-1
Statistics is low. need more data!
R molecule model in trouble?
45
Evidence of X(3872)??J/?
Evidence for sub-threshold decay X(3872)??J/?
hep-ex/0505037
275M BB
X(3872)
275M BB
M(??-?0) (GeV/c2)
M?J/? (GeV/c2)

• 10.6?3.6 events
• 4.3 ?

• 13.6 ?4.4 events
• stat. sig. 4.0 ?

hep-ex/0505037
The evidence of the two decay modes suggests the
C parity of X(3872) be 1
46

• no signals for charged partners of X(3872)
• no signal for X(3872) ? J/? ?
• no evidence in ?? fusion and radiative
  production at
• CLEO

234M BB
PRD 71 (2005) 031501
90M BB
PRL 93 (2004) 041801
PRL 94 (2005) 032004
47
Mass of X(3872)
DD- threshold
Mavg 3871.9?0.6 MeV/c2 , ?lt2.3 MeV/c2 (90
C.L.) D0D0 3871.3 ? 1.0 MeV/c2 DD
3878.6 ? 1.0 MeV/c2
48

• 0-- violates parity, is ruled out (exotic)
• Absence of DD decays, Jp0, 1- and 2 unlikely
• Evidences of X??J/? and ?J/? exclude C-1

0-- exotic violates parity 0- (hc) 0 DD allowed (cc0) 0- exotic DD allowed
1- - DD allowed (y(3S)) 1- exotic DD allowed 1 (cc1) 1- (hc)
2- - (y2) 2- (hc2) 2 DD allowed (cc2) 2- exotic DD allowed
49
Analyses of Angular distributions
a sample of X(3872) produced via B? K X(3872)
(256 pb-1)

• 0 is unlikely

• 0- is unlikely

• 1 looks OK

c2/dof 11/9
c2/dof18/9
c2/dof 34/9

cosq
cosql
c2/dof 5/9
c2/dof34/9
cosqlp(? frame)
cosc
50

• Search for B? K D0D0 (

D0?D0p0)
preliminary
2 is not favored
M(D0D0p0)
11.33.6 sig.evts B(B?KX)B(X?D0D0?0)(2.20.70
.4)x10-4
51
the results favor a 1 X(3872)
However

• the statistics is low for
• evidence of X(3872)??J/?
• evidence of sub-threshold decay X(3872)??J/?
• the statistics is low to use ?2 test in the
  angular distributions
• X(3872) ? ?J/? ???-J/??
• wait for more statistics and BaBars confirmation

evidence of B? K D0D0 (
D0?D0p0)
52
Possible Interpretations of X(3872)

• cc charmonium state
• T. Barnes and S. Godfrey, PRD 69 (2004) 054008
• E.J. Eichten, K. Lane and C. Quigg, PRD 69
  (2004) 094019
• Dominant 1 (2P) cc component
• D0D0/D0D0 continuum component
• C. Meng, Y.J. Gao and K.T. Chao,
  hep-ph/0506222
• D0D0 molecule
• N.A. Tornqvist, PLB 590 (2004) 209
• M.B. Voloshin, PLB 579, 316
• C.Y. Wong, PRC 69 (2004) 055202
• E. Braaten and M. Kusunoki, PRD 69 (2004)
  074005, 71(2005) 074005
• E.S. Swanson, PLB 588 (2004) 189

53

• Hybrid ccg
• B.A. Li, PLB 605 (2005) 306
• Vector glueball a small mixture of cc
• K.K. Seth, hep-ph/0411122
• Diquark-antidiquark bound state cucu
• L. Maiani, F. Piccinini, A.D. Polosa and V.
  Riquer, PRD 71(2005)014028
• S-wave threshold enhancement in
• D.V. Bugg, PRD 71 (2005) 016006

D0D0 scattering
54
Selected topics on quarkonium decays J/?
decays ?(3770) non-DD decays
55
The study of ?

• evidence for a low mass pole in the early DM2 and
  BESI data on J/? ? ??? .
• huge event concentration in the I0 S-wave ??
  channel seen in M?? 500 600 MeV in the pp
  central production exp.
• to explain ?? scattering phase shift data,?
  should be introduced in chiral perturbative
  theory.
• FNAL E761 exp. D ???-? data

56
The ? pole in at BESII
?
?
M(??-)
Different parameterizations of BW are used in
PWA.
Averaged pole
BES, PLB 598 (2004) 149
57
Amplitude analysis of at BaBar

• Direct CP-violating asymmetries and constraints
  on the magnitudes
• and the phases of the CKM matrix elements can
  be obtained from
• individual decay channels in
• are dominated by
  decays through intermediate
• resonances.
• full amplitude analysis of this decays helps to
  clarify the
• natures of the resonances involved.

BaBar 210.3 fb-1
No evidence for ?.
58
The study of ?

• A possible ? pole is controversial.
• Some analyses of LASS K? scattering data needs
  ?(800), some dont.
• Scadron et al. favors a nonet made up of ?,
  ?(800), f0(980) and a0(980).
• Julich group used t-channel exchanges to explain
  K? scattering data.
• evidence of ? in FNAL E791 data on D ?K-??
• slightly lower statistics of CLEO D0 ?K-??0
  data find no evidence
• of ?
• FOCUS data on K?K-??? require K0 interfere
  with either a
• constant amplitude or a broad 0 resonance in
  K?

59
BES observed ? in J/??KK??K?K?
PWA result ? is needed in the fit. Pole
position of ?
BES II 58 M J/?
hep-ex/0506055 Submitted to PLB
60
Dalitz plot analysis of B?K?? at Belle and BaBar
Belle(?10-6) Babar (?10-6)


not included
No ? included in the fit.
Disagree !
Belle, PRD 71 (2005) 092003 BABAR-PUB-05/027
61
?(3770) non-DD decays

• ?(3770) decays most copiously into DD.
• ?(3770) is a mixture of the 13D1 and 23S1,
• other ?(2S)-like decays for ?(3770) are
• expected. (mixing angle 12?2o).
• Many theoretical calculations estimate the
• partial width for ?(3770) ? ??- J/?.
• (Lipkin, Yan, Lane, Kuang, Rosner)
• Recently, Kuang obtained a partial width for
• ?(3770) ? ??- J/? in the range of
• 25 -113 keV. (Y.P. Kuang, PRD 65 (2002) 094024)

62
BES first reported ?(3770) non-DD decay
?(3770) ? ??- J/?
Open histogram is for ee-, histogram in yellow
is for ??-
The histogram is ? error bars are ??
data
MC
27.7 pb-1
20 times large than the data
mainly
hep-ex/0307028 PLB 605 (2005) 63
63
?(3770) ? ?? J/? is finally confirmed by CLEO
CLEO Preliminary
281pb-1
281pb-1
3.8 ?
13 ?
64
Observation of ?(3770)???c1??? J/? at CLEO
CLEO Preliminary
281pb-1
????c1
E? (MeV)
65
Search for ?(3770) ? ?? and KsKL at BES
?(3770) ? ??
at ?(3770)
at 3.65GeV
M?? (GeV/c2)
M?? (GeV/c2)
for ?? process
?(3770) ? KsKL
17.7 pb-1
MC simulated signal, not normalized
Ks sideband
PRD 70 (2004) 077101
Ks momentum (GeV/c)
66
Measurement of ?(3770) ? VP decays at CLEO
67
Search for non-DD decays of ?(3770) at CLEO
55.8 pb-1
68
281 pb-1 data at 3.77 GeV 21 pb-1 data at
3.67 GeV

• for each channel, on-?(3770) yields consistent
• with continuum prediction except
• Br(?(3770) ? ??) (3.1?0.6?0.3?0.1)?10-4
• ?(3770) ? ??-?0, ?0?0 and KK- are suppressed.
• form factors of ??0, ?? and ?? are obtained

Form factors with statistical errors
69
I apologize for not being able to cover many
interesting results related to this topic (so
broad!) due to the limitation of my own knowledge
and also the limitation of time (30 mins.).
70
summary

• New observation of X(1835) in J/? ? ????- at
  BES. It is likely to be a pp bound state (7.7?).
• Observation of X(3940) in double charmonium
  production in ee- annihilation at Belle. It is
  likely to be a charmonium state.
• Observation of Y(3940) at ?J/? threshold in B ? K
  ?J/? at Belle. Might be a ccg?
• New observation of Y(4260) in ??- J/? spectrum
  at BaBar (gt8?). A charmonium state?

71
Summary (contd)

• In double charmonium production (Belle Babar),
• ?(ee-?J/? ?c) 10?theory, inclusive ?
  5?theory
• Many charm and beauty production results from
  HERA
• hc observed at CLEO
• first evidence of a fully reconstructed decay
  mode of Bc at CDF.
• More decay modes of X(3872) from BaBar and Belle.
  X(3872) favors 1
• ? and ? observed at BES
• BESs ?(3770)???-J/? non-DD decay is confirmed
  by CLEO. The results are consistent within the
  error.
• ?(3770) ? ??c1 is first observed by CLEO. Many
  decay modes of ?(3770) are measured.

72
Thank you
??