The mystery of the X(3872)

1
Y(4260)
New Particles
X(3940)
X(3872)
Y(3940)
Z(3930)
????
?????? ??????
University of Hawaii Future of Heavy
Flavors ???? 7/23-24/06

2
B-factories are Charmonium factories

• cc production mechanisms _at_ a B factory
• B meson decays
• ee- annihilation
• gg collisions
• ee- radiative return (isr)

3
cc production in B decays
J 0 or 1
j½
j½
Spectator model says Jcc 0 or 1 should dominate
exclusive B?K(cc) decays.
4
Allowed decays all have Bf10-3 from PDG2004
hcK 0.9 x10-3
J/yK 1.0 x10-3
J/yK 1.4 x10-3
J/yK12701.8 x10-3
yK 0.7 x10-3
yK 0.9 x10-3
cc0K 0.6 x10-3
cc1K 0.7 x10-3
B?K cc(J2) still not seen

5
ee- ? J/y (cc)
J/y
hc
cc0
X
hc
X (almost) always contains (cc) C(X) 1
M(X)
consistent with bkg
6
gg? DD
JPC 0, 2
ee- ? g (cc)
cc
JPC 1--
7
XYZ particles in Belle

• X(3872)
• pp- J/y in B?Kpp-J/y
• Z(3930)
• DD in gg ? DD
• Y(3940)
• wJ/y in B?K wJ/y
• X(3940)
• ee- ?J/y X ee- ? J/y DD
• Y(4260)
• pp-J/y in ee- ?g pp- J/y

NEW
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gg ? Z(3931) ?DD at Belle
sin4q (J2)
Belle PRL 96, 082003 (2006)
41? 11 evts (5.5?) M3931 ? 4 ? 2 MeV ?20?8 ?3
MeV
M(DD) GeV
Matches well to cc2 expectations
9
Z(3930) candidate for the cc2
M 3931 MeV is 45 MeV low G20MeV too narrow?
3931
Masses from Barnes, Godfrey Swanson PRD 72,
054026 (2005)
10
ee- ? J/y X(3940)
ee-?J/y X
hep-ex 0507019 submitted to PRL
11
X(3940)?DD seen(?DD ?wJ/y not seen)
B(DD)lt41
B(DD)gt45
From X(3940) ? DD M (3943 6 6) MeV G lt 52
MeV at 90CL
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Is the X(3940) the hc?
M 3943 MeV is 150 MeV low Glt52MeV too narrow?
3940
13
X(3872) in B?Kpp-J/y
y?pp-J/y
X(3872)?pp-J/y
M(ppJ/y)
PRL 91, 262001
14
Also seen in pp
X(3872)
D0
CDF
11.6s
X(3872)
PRL 93, 072004 (2004)
PRL 93, 162002 (2004)
Production properties similar to those of the y
hep-ex/0406022
15
C1 is established
M(pp) looks like a r
X(3872)?gJ/y seen in
CDF
PRL 96 102002
Belle
hep-ex/0505037
Belle

X(3872)?wJ/y seen
Belle
16
0 0-
er?eJ/y
k?(erxeJ/y)
Ruled out by Belle
qlp
y
c2/dof34/9
c2/dof 34/9
cosq
cosqlp
cosy
rule out 0 0 -
17
Angular analysis from CDF
1 or 2-
Ilya Kravchenko FPCP06
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Belle Threshold peak in B?KD0D0p0
Belle hep-ex/0606055 ? today!
M(DDp)
DE
0.7 -1.7
M3875.4 ? 0.7 ? 0.8 MeV
Br(B?KX)Bf(X?D0D0p0 ) (1.27 ? 0.31
)x10-4
0.22 -0.39
Br(X?D0D0p0) Br(X?pp-J/y)
10
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Comments on the D0D0p0 mass peak
PDG MX3872 3871.2 ? 0.5 MeV
2s discrepancy
PDG05
?
2xPDG error on mD0 (could be ? 2.0 MeV)
0.7 -1.7
Fitted M 3875.4 ? 0.7 ? 0.8 MeV
DD Binding Energy?
Here error on mD0 drops out
M(mD0 mD0) 4.3 ? 0.7 MeV
0.7 -1.7
Nominally 2.3s above D0D0 threshold (but errors
are non-Gaussian)
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X(3872) has no satisfactory cc assignment
3872
cc1
Br(gJ/y) too small Br(rJ/y) too big
hc2

• hc2?rJ/y ispin forbidden
• D0D0p0 _at_ thresh. suppressed
• B?Kcc(J2) suppressed

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Y(3940) in B?K wJ/y
M3940 11 MeV G 92 24 MeV
G(Y3940 ? wJ/y) gt 7 MeV (an SUF(3) violating
decay)

this is 103 x G(y ? hJ/y) (another SUF(3)
violating decay)
if the Z(3930) is the cc2 the Y(3940) mass is
too high for it to be the cc1
M(wJ/y) MeV
PRL94, 182002 (2005)
22
Is there a cc slot for Y(3940) ?
hc
Mass is low
cc1
Can M(cc1)gtM(cc2)?
3940
3931
cc0

23
ee- ? gisr Y(4260) at BaBar
BaBar PRL95, 142001 (2005)
Not seen in ee- ? hadrons
X.H. Mo et al, hep-ex/0603024
Y(4260)
4260
BES data
s(ee-??p-J/?)50 pb
G(Y4260?pp- J/y) gt 1.6MeV _at_ 90 CL
4260
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Y(4260) at CLEO-III
ISR ?(1S)-?(4S) 13.3 fb-1
Consistent results
R.Poling _at_ Charm 2006
25
Y(4260) at Belle
M4295 ? 10 11 MeV G 133 ? 26 13 MeV
-5

Select ee-? pp- ll- X Nchg4
Mll-MJ/y?30MeV pJ/ygt2 GeV Mppgt0.4GeV

-6

data
?
4.2ltMppJ/ylt4.4
Preliminary
MC
MX
For y?pp-J/y in the same data M(y)
3685.3 ? 0.1 MeV (PDG M(y)3686.09 ? 0.04)
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BaBar vs CLEO vs Belle
BaBar CLEO III Belle (Preliminary)
N 125 ? 23 (8?) 14.1 5.2 (4.9?) 165 ? 24(stat) (gt7s)
Mass(MeV) 4259 ? 8 2 4283 17 ? 4 4295 ? 10 11
Width 88 ? 23 6 70 40 ? 5 133? 26 13
-4.2
-5
-6
-16
-6
-4
-25
2.5s different
Full report from Belle at ICHEP in Moscow
27
No 1-- cc slot for the Y(4260)
X.H. Mo et al, hep-ex/0603024
4280

4280
28
DD threshold in relation to the Y(4260)
D spectrum
No obvious distortions
4.28-mD
M(pp-J/y) GeV
29
Another one from BaBar?
y(4352)?pp- y (produced via radiative return)
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summary

• Z(3931) (gg?DD)
• Probably the cc2
• X(3940) (ee- ? J/y X)
• C1
• Could be the hc (albeit with some stretching)
• X(3872)
• JPC 1
• Br(X?pp- J/y) large
• Br(X?D0D0p0) seen 10xBr(X?pp-J/y)

DD

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summary contd

• Y(3940)
• G( Y3940? wJ/y) gt7 MeV too
• large for charmonium
• Mass too low for a hybrid
• Y(4260)
• Confirmed by Belle but at a higher mass
• G(y4260?pp-J/y)gt1.6 MeV also very large
• JPC1--, but not seen in ee-? hadrons
• - Straddles the DD threshold, but with no
  obvious distortions to the ppJ/y line-shape

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conclusions
(mine, not Belles)

• There is a new hadron spectroscopy in the 3.54.5
  GeV mass region
• Maybe more than one
• The new states are characterized by large partial
  widths (Bfs) to hadronsJ/y
• Br(X(3872)?rJ/y) gt 4.3 (Isospin1)
• G(Y(3940)?wJ/y) gt 7 MeV (SU(3) octet)
• G(Y(4260)?pp-J/y) gt 1.6 MeV
• There is no apparent transition at the DD mass
  threshold

33
Thank You
34
Back-up slides
35
Look at ee-?J/y D(D())

• Reconstruct a J/y a D
• use D0?K-p D?K-pp
• Determine recoil mass

36
Inclusive B?Kx from BaBar
Fully reconstructed B- tags
?
37
Mpp