Transcript The mystery of the X(3872) - Istituto Nazionale di Fisica

XYZ News from Belle
Stephen L. Olsen, Univ of Hawai’i
QWG 2006 June 26-30, Brookhaven
B-factories are Charmonium factories
cc production mechanisms @ a B factory:
•
B meson decays
•
e+e- annihilation
•
gg collisions
•
e+e- radiative return (isr)
cc production in B decays
j=½
J = 0 or 1
j=½
Spectator model says Jcc= 0 or 1 should
dominate exclusive BK(cc) decays.
Allowed decays all have Bf~10-3
from PDG2004
hcK 0.9 x10-3
J/yK 1.0 x10-3
J/yK* 1.4 x10-3
J/yK12701.8 x10-3
y’K 0.7 x10-3
y’K* 0.9 x10-3
cc0K 0.6 x10-3
cc1K 0.7 x10-3
BK cc(J=2) still not seen
e+e-  J/y + (cc)
J/y
X
hc
X (almost) always
contains (cc)
C(X) = +1
cc0
M(X)
consistent
with bkg
hc’
gg DD
JPC = 0++, 2++
e+e-  g (cc)
cc
JPC = 1--
XYZ particles in Belle
• X(3872)
–
p+p- J/y in BKp+p-J/y
• Z(3930)
– DD in gg  DD
• Y(3940)
–
wJ/y in BK wJ/y
• X(3940)
– e+e- J/y X & e+e-  J/y DD*
• Y(4260)
–
p+p-J/y in e+e- g p+p- J/y
NEW
gg  Z(3931) DD at Belle
Belle PRL 96, 082003 (2006)
sin4q (J=2)
41 11 evts (5.5)
M=3931  4  2 MeV
=208 3 MeV
M(DD) GeV
Matches well to cc2’ expectations
Z(3930): candidate for the cc2’
3931
M= 3931 MeV is
~45 MeV low
=20MeV too narrow?
Masses from
Barnes, Godfrey & Swanson
PRD 72, 054026 (2005)
e+e-  J/y X(3940)
e+e-J/y + X
hep-ex 0507019 submitted to PRL
X(3940)D*D seen
(DD & wJ/y not seen)
B(DD)<41%
B(D*D)>45%
From X(3940) → D*D:
M = (3943 ± 6 ± 6) MeV
 < 52 MeV at 90%CL
Is the X(3940) the hc”?
M= 3943 MeV is
~150 MeV low
<52MeV too narrow?
3940
X(3872) in
+
BKp p J/y
y’p+p-J/y
X(3872)p+p-J/y
PRL 91, 262001
M(ppJ/y)
Also seen in pp
D0
X(3872)
CDF
11.6
X(3872)
PRL 93, 072004 (2004)
PRL 93, 162002 (2004)
Production properties similar to those of the y’
C=+1 is established
X(3872)gJ/y seen in:
M(pp) looks like a r
CDF
PRL 96 102002
Belle
hep-ex/0505037
&
Belle
X(3872)”w”J/y seen
Belle
0++
ereJ/y
0-+
k(erxeJ/y)
Ruled out by Belle
qlp
y
c2/dof=34/9
c2/dof = 34/9
|cosq|
|cosqlp|
rule out 0++ & 0 -+
|cosy|
Angular analysis from CDF
Ilya Kravchenko: FPCP06
1++
or
2-+
Belle: Threshold peak in BKD0D0p0
M(DDp)
Belle hep-ex/0606055  today!
DE
M=3875.4  0.7
+0.7
-1.7
 0.8 MeV
Br(BKX)Bf(XD0D0p0 )
+0.22
= (1.27  0.31-0.39 )x10-4
Br(XD0D0p0)
~ 10
Br(Xp+p-J/y)
Comments on the D0D0p0 mass peak
PDG MX3872: 3871.2  0.5 MeV
~2 discrepancy
PDG05

Fitted M: 3875.4  0.7
DD* “Binding Energy?”:
M–(mD0+ mD*0) =
+0.7
-1.7
 0.8 MeV
+4.3  0.7
+0.7
-1.7
2xPDG error on mD0
(could be  2.0 MeV)
MeV
Here error on
mD0 drops out
Nominally ~2.3 above D0D*0 threshold
(but errors are non-Gaussian)
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 @ thresh. suppressed
• BKcc(J=2) suppressed
Y(3940) in BK wJ/y
M≈3940 ± 11 MeV
≈ 92 ± 24 MeV
(Y3940  wJ/y) >
~ 7 MeV
(an SUF(3) violating decay)
this is 103 x (y’  hJ/y)
(another SUF(3) violating decay)
M(wJ/y) MeV
PRL94, 182002 (2005)
if the Z(3930) is the cc2’
the Y(3940) mass is too
high for it to be the cc1’
Is there a cc slot for Y(3940) ?
3940
hc”
Mass is low
cc1’
Can M(cc1’)>M(cc2’)?
3931
cc0’
“
“
“
“
+
e e
 gisr Y(4260) at BaBar
BaBar PRL95, 142001 (2005)
Not seen in e+e-  hadrons
X.H. Mo et al, hep-ex/0603024
233 fb-1
Y(4260)
4260
pp
(e+e- + -J/
BES data
y)~50 pb
(Y4260p+p- J/y) > 1.6MeV @ 90% CL
4260
Y(4260) at CLEO-III
13.3 fb-1
ISR
(1S)-(4S)
13.3 fb-1
BaBar
Consistent
results
CLEO III
N
125  23 (~8) 14.1 +5.2
(4.9)
-4.2
Mass (MeV)
4259  8 +2
-6
4283 +17
-16  4
Width (MeV)
88  23 +6
-4
70 +40
5
-25
R.Poling @ Charm 2006
Y(4260) at Belle
Select e+e-
p+p-
ℓ+ℓ-
+X; Nchg=4
Mℓ+ℓ-=MJ/y30MeV; pJ/y>2 GeV; Mpp>0.4GeV
|
data
4.2<MppJ/y<4.4
MC
MX
For y’p+p-J/y in the same data:
M(y’) = 3685.3  0.1 MeV
(PDG: M(y’)=3686.09  0.04)
M=4295  10
 = 133  26
+11
-5
+13
-6
MeV
MeV
BaBar vs CLEO vs Belle
BaBar
CLEO III
Belle (Preliminary)
N
125  23 (~8)
14.1 +5.2 (4.9)
165  24(stat) (>7)
Mass(MeV)
+2
4259  8 -6
4283 +17
4
-16
4295  10 +11
-5
Width
88  23 +6
70 +40  5
133 26 +13 6
-4
-4.2
-25
~2.5 different
“Full” report from Belle at ICHEP in Moscow
-
No 1-- cc slot for the Y(4260)
X.H. Mo et al, hep-ex/0603024
4280
4280
DD** threshold in relation to the
“Y(4260)”
D** spectrum
No obvious
distortions
4.28-mD
M(p+p-J/y) GeV
summary
• Z(3931)
(ggDD)
– Probably the cc2’
• X(3940)
(e+e-  J/y X)
D*D
– C=+1
– Could be the hc” (albeit with some stretching)
• X(3872):
– JPC = 1++
– Br(Xp+p- J/y) large
– Br(XD0D0p0) seen; ~ 10xBr(Xp+p-J/y)
summary cont’d
• Y(3940)
– ( Y3940 wJ/y) >7 MeV too
large for charmonium
– Mass too low for a hybrid
233 fb-1
• “Y(4260)”
– Confirmed by Belle but at a higher mass
– (y4260p+p-J/y)>1.6 MeV also very large
– JPC=1--, but not seen in e+e- hadrons
- Straddles the D**D threshold, but with no obvious
distortions to the ppJ/y line-shape
conclusions
•
There is a new hadron spectroscopy in the
3.5~4.5 GeV mass region
–
•
Maybe more than one
The new states are characterized by large
partial widths (Bfs) to hadrons+J/y
–
–
–
•
(mine, not Belle’s)
Br(X(3872)rJ/y) > 4.3% (Isospin=1)
(Y(3940)wJ/y) > 7 MeV (SU(3) octet)
(Y(4260)p+p-J/y) > 1.6 MeV
There is no apparent transition at the D**D
mass threshold
Thank You
Back-up slides
Look at e+e-J/y D(D(*))
•Reconstruct a J/y & a D
•use D0K-p+ & D+K-p+p+
•Determine recoil mass
Inclusive BKx from BaBar
Fully reconstructed B- tags
?