stephen olsen u. of hawai’i & 高能所 北京 yz e otic x mesons sookyung choi scientist of...
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Stephen OlsenU. of Hawai’i
&高能所 北京
YZ
e oticX Mesons
Sookyung Choi Scientist of the monthAug 2004, Korea
Constituent Quark Model(CQM)
(& 6 antiquarks)
Mesons: q q
c: c+2/3
c: C-2/3
+ : s-1/3
s+1/3
s+1/3
c-2/3
u-2/3
b+1//3
u+2/3
- : b-1/3
S=1/3
b+1/3
t-2/3c+2/3
b-1/3
t+2/3
6 quarks
Baryons: qqq
u-2/3
d+1/3 s+1/3
u+2/3
d-1/3 s-1/3
Gell-Mann
Zweig
Are there other color-singlet arrangements?
Pentaquarks:e.g. an S=+1 baryon
(only anti-s quark has S=+1)
Glueballs:gluon-gluon color singlet states
Multi-quark mesons:
qq-gluon hybrid mesons
u cuc
c c
ud
usd
Non-quark model states expected in QCD
Our approach:look for non-qq mesons
c c
u cuc
4 (& 6) quark states
“hybrid” qq-gluon states
u u
uud
d
Fit the M(pp) distribution
Best fit to this peakis a resonance withpeak mass below thepp mass threshold
M=1835 MeV no know 100MeV resonance
A pp bound state (baryonium)?
p n p p
deuteron:
loosely bound 3-q 3-
q color singlets with Md = 2mp-
baryonium:
loosely bound
3-q 3-q color singlets with Mb = 2mp-
?
attractive nuclear force attractive force?
There is lots & lots of literature about this possibility
Expectation for pp bound state meson
mp +mp
Above threshold
Xpp ~100%
below-threshold p
and p annihilate to
mesons
I=0, JPC=0-+ init. state:pp ’ is common
X(1835): “6-quark” meson?
3 quarks+
3 antiquarks
•Need to confirm JPC of the ’ peak is 0-+
•Need to find it in other common 0-+ pp annihilation channels
jobs for BESIII
uu
u
ud
d
Charmonium is of particular interest
because it is an especially good system
to use to search for non-qq mesons
a cc meson has to fit into one of these slots:
If it doesn’t, it is a good candidate for a non qq meson
Lots new on the “XYZ” particles
• X(3872)– J/ in BKJ/
• Z(3930)– DD in DD
• Y(3940)– J/ in BK J/
• X(3940)– e+e- J/X & e+e- J/ DD*
• Y(4260)– J/ in e+e- J/
• Y(4325)– +-’ in e+e-+-’
Y(4008)?
Y(4250)
Y(4370)
Y(4660)
X(3880)DD- e+e- J/ DD
X(4160)D*D*- e+e- J/ D*D*
Z+(4430)+ - BK+’
New Belle/BaBar results:(Summer 2007)
Status spring 2007:
confirmed by BaBar
updated by Belle
M() looks like
2/dof = 43/39 (CL=28%)
kinematiclimit≈m
PRL 96 102002
CDFBelle
• Belle & CDF: JPC = 1++ most likely
What’s new with the X(3872)?
BaBar confirms Belle’s DD threshold enhancement
Mass is 3.8±1.2 MeV above WAvg X(3872)J/ mass;
(~3is this significant?
Both groups see a high mass value
Belle’s BKSX & BK±X comparison
M = 0.22 ± 0.90 ± 0.27 MeV
KS mode K± mode
“molecular” modelspredicted this to be <<1(Braaten et al PRD 71 074005)
“diquark-antidiquark” modelspredicted this to be 8±3 MeV
(Maiani et al PRD 71 014028)
Confirms an earlier BaBar result
Is there a cc slot for the X(3872)?
3872 rJ/ too small
r(J/) too big
1++(c1’)
cJ/ ispin forbidden D0D00 @ thresh.suppressed BKcc(J=2) suppressed
2-+(c2)
Y(3940) in BK J/
M≈3940 ± 11 MeV≈ 92 ± 24 MeV
Belle PRL94, 182002 (2005)
M(J/) MeVM2(K) GeV2
M2(
J
) G
eV2
S-K Choi, SL Olsen et al,
Y(3940) properties
Belle PRL94, 182002 (2005)
M(J/) MeV
(Y3940 J/ > 7 MeV (an SUF(3) violating decay)
~
this is 103 x (’ J/ (another SUF(3) violating decay)
if the Z(3930) is the c2’the Y(3940) mass is toohigh for it to be the c1’
Confirmed by BaBar this summer
B±K±J/ B±K±J/
B0KSJ/
M2(K)
J)
ratio
Some discrepancy in M & ; general features agree
G.CibinettoEPS-2007
Is there a cc slot for Y(3940) ?
Can M(c1’)>M(c2’)?c1’
Mass is lowc”
“ “ “ “c0
’
39403931
For any charmonium assignment, [Y(3940) J/ is too large.
e+e- isr Y(4260) at BaBar
233 fb-1
Y(4260)
BaBar PRL95, 142001 (2005)
~50pb
M=4259 8 +2 MeV
= 88 23 +6 MeV -6
-9
fitted values:
Not seen in e+e- hadrons
(Y4260 J/) > 1.6MeV @ 90% CL
X.H. Mo et al, PL B640, 182 (2006)
4260
4260
BES data
~3nb
peakY(4260)+J/pb
Huge by charm
onium
standards
“Y(4260)” at Belle (New) M=4247 12 +17 MeV
= 108 19 ±10 MeV -32
M=4008 40 +114 MeV
= 226 44 ±87 MeV -28
???
C.Z Yuan et al (Belle) arXiv:0707.2541To appear in PRL
M=4259 8 +2 MeV
= 88 23 +6 MeV -6
-9
BaBar values:
Resonance?Thresh effect?…?
Is the Y(4260) a cc-gluon hybrid?
c c
• qq-gluon excitations predicted 30 yrs ago • lowest 1-- cc-gluon mass expected at ~4.3 GeV • relevant open charm threshold is D**D (~4.28 GeV) • (J/) larger than that for normal charmonium • (e+e-) smaller than that for ordinary charmonium
Horn & Mandula PRD 17, 898 (1977)
Banner et al, PRD 56, 7039 (1997); Mei & Luo, IJMPA 18, 15713 (2003)
Isgur, Koloski & Paton PRL 54, 869 (1985)
McNeile, Michael & Pennanen PRD 65, 094505 (2002)
Close & Page NP B443, 233 (1995)
Y(4260) s
eems t
o matc
h all
of these
!!!
BaBar’s ’ peak at 4325MeV
Nbkg = 3.1 1.0
Nevt = 68 (<5.7 GeV/c2)
2-prob < 5.7 GeV/c2
Y(4260) 6.5 10-3
(4415) 1.2 10-13
Y(4320) 29%
e+e-ISR ’
M=4324 24 MeV
= 172 33 MeV
above all D**D thresholds
S.W.Ye QWG-2006 June 2006
Not Compatible with the Y(4260)
D1D
D2D
298 fb-1 (BaBar) hep-ex/0610057
BaBar PRL 98 252001 (2007)
4325 MeV ’ peak in Belle (new)
M=4324 24 MeV
= 172 33 MeV
548 fb-1
X.L. Wang et al (Belle) arXiv:0707.3699
Two peaks!
M=4664 11 ±5 MeV
= 48 15 ±3 MeV
M=4361 9 ±9 MeV
= 74 15 ±10 MeV
BaBar values
(both relatively narrow)(& both above D**D thresh)
(& neither consistent with 4260)
4260
M(±’) from BK ±’
M2(K) GeV2
M2(’)
GeV
2
K. Abe et al (Belle) arXiv:0708.1790
K*KK2*K Veto Veto
M(’) GeV
6.5
M = 4433 ±4 ±1 MeV
tot = 45 +17 +30 MeV
Nsig =124 ± 31evts-13 -11
Comments on the Z+(4430)
Not a reflection from the K system~
No significant signal in B KJ/
It has non-zero charge not cc or hybrid
Mass, width & decay pattern similar to Y(4360) & Y(4660)
conclusions• There seems to be a new hadron spectroscopy in the M=3.5~5
GeV region– Maybe more than one– Bodes well for BESIII, Super-B factories & PANDA
• Some states are narrow even though they are far above decay thresholds
– e.g. Y(4660)’ & Z+(4430)’ have large Q but ≈50 MeV
• characterized by large partial widths (Bfs) to hadrons+J/(or ’)
– Br(X(3872)J/) > 4.3% (Isospin=1)– (Y(3940)J/) > 7 MeV (SU(3) octet)– (Y(4260)J/) > 1.6 MeV
• States that decay to ’ not seen decaying to J/ (and vice-versa) – Bf(Y(4660)’) >> Bf(y(4660)J/) same for Y(4360) & Z(4430’– Y(4260) not seen in Y(4260)’
• The new 1-- states are not apparent in the e+e-D(*)D(*) cross sections
• There is no evident transitions at the D**D mass threshold
(mine)
some of the states are near thresholds,but this is not a universal feature
DSDS thresholdsDD thresholds
D*D*
DD*
DD
tot
Y(4
660)
Y(4
360)
Y(4
260)
Y(4
008)
None of the 1-- peaksmatch structures in e+e- hadrons
Pakhlova (Belle) PRL 98, 092001 (2007)
Lots of pieces
Y(4360)
Y(4
660)
Y(4260)
Y(4
008)
X(3872)
X(3940
)
X(416
0
)
Z(4430) Y(3940)
Are the
y al
l fro
m the
sam
e pu
zzle
?