The mystery of the X(3872)
Download
Report
Transcript The mystery of the X(3872)
????
Y(4260
Y(3940)
X(3940)
Z(3930)
X(3872)
New
Particles
Ѕтефан Олавич
University of Hawai’i
Future of Heavy Flavors
ИТЗФ 7/23-24/06
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 BK(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
BK 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 BKp+p-J/y
• Z(3930)
– DD in gg DD
• Y(3940)
–
wJ/y in BK 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
=208 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
+
BKp 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++
ereJ/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 BKD0D0p0
M(DDp)
Belle hep-ex/0606055 today!
DE
M=3875.4 0.7
+0.7
-1.7
0.8 MeV
Br(BKX)Bf(XD0D0p0 )
+0.22
= (1.27 0.31-0.39 )x10-4
Br(XD0D0p0)
~ 10
Br(Xp+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 •
hc2rJ/y ispin forbidden
• D0D0p0 @ thresh. suppressed
• BKcc(J=2) suppressed
Y(3940) in BK 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
(Y4260p+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/y30MeV; 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
Another one from BaBar?
y(4352)p+p- y’ (produced via radiative return)
summary
• Z(3931)
(ggDD)
– 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(Xp+p- J/y) large
– Br(XD0D0p0) seen; ~ 10xBr(Xp+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
– (y4260p+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 D0K-p+ & D+K-p+p+
•Determine recoil mass
Inclusive BKx from BaBar
Fully reconstructed B- tags
?
Mpp