cc spectroscopy at elle s.l.olsen hawaii qwg 2004 worksop ihep beijing _
TRANSCRIPT
cc spectroscopy at elle
S.L.Olsen Hawaii
QWG 2004 WorksopIHEP Beijing
_
B-factory bonuses:
new insights/puzzles about charmonium
c’ X(3872)
M(KsK)
BK Ks BK +-J/
M(+-J/
ccc0
J/recoil mass
e+e-J/cc
??‘
BK J/
M(J/
??
bccs is a dominant process
b
c
c
s
Vcb
cosC
J/, ’, c, c1,…
Brs~10-2
(inclusive)
CKMfavored
W-
B mesons are a good source for charmonium and other cc states
>900pb-1/day(~1M BBs/day)
1.2x1034/cm2/s
KEKB is a good source of Bs
Kinematic variables for the (4S)
CM energy difference:
Beam-constrained mass:
22 )()2( 'c
ppEm KCMbc
BK c
BKc
2/' cmK EEEEc
B
Bϒ(4S)
Ecm/2
e e
Ecm/2
KSK
KSK
Mbc
E
1st Observation of the c‘
BK (KSK±Ŧ)Mbc for 40 MeV M(KSK) slices
3000 MeV
3640 MeV
BK c
BK c’42fb-1
KSK
KSK
Fit each binNevt = 45.3 ± 12.6 Mc’ = 3653 ± 10 MeV
c’ = 33 ± 22 MeV
Nevt = 90.5 ± 14.9 Mc = 2978 ± 5MeV
c = 33 ± 16 MeVM(KSK)
Mbc E
c:
c’:3.55 GeV
3.60 GeV
3.65 GeV
3.70 GeV
3.75 GeV
…
…
S.K. Choi et al PRL 91, 102001
Subsequent measurements
confirm higher mass value
KSK
KSK
eeJ/X
Mx
BaBar(preliminary)
3630 MeV
3642 MeV
3633 MeV
CLEOhep-ex/0306060
elle
c c‘
c’: current status
Mavg =3637±4 MeV(Crystal Ball excluded)
M(1S) = MJ/ – Mc =117±1 MeV
M(2S) = 49 ± 4 MeV
gets smaller
The X(3872) with 253 fb-1
B±K±+-J/
Nev = 48.6 ± 7.8M = 3872.4 ± 0.7 MeV
Now M( is really -like
X(3872) MassD+D*- threshold
Look at BK J/
M()
M(J
/
)
BK J/
XJ/ BK X(3872);
1: look at BK J/Dalitz Plot
M
Mbc
EM
2(J
/
)
M2(K)
BK* J/K
cut here
Slice into 40 MeV-wide M(J/) bins
Large deviationfrom phase-space
Fit
Slice into 40 MeV-wide M(J/) bins
Adding a BWhelps
FitM≈3940 ± 11 MeV≈ 92 ± 24 MeV
M(K) for the signal region
M(K) (GeV)
3880 <M(J/)<3900 MeV
No peakingIn M(K)
Look back at the masses
76’s28’s
Very clear signal
20’s26’s
What is it?• Charmonium?
– Conventional wisdom: J/ should not be a discovery mode for a cc state with mass above DD & DD* threshold!
• Some kind of -J/ threshold interaction?– the J/ is not surrounded by brown muck; can it act like an ordinary hadron?
• cc-gluon hybrid?– Predicted by lattice QCD, including states with large
hadron+cc widths, but predicted masses are ~ 4.4 GeV
J/
Next: B±K± X(3872) J/
M()
M(J
/
)
BK X(3872)
J/
look along here
M(3 J/) = MX(3872) ± 16.5 MeV(±3)
Look at 25 MeV-wide M() mass bins
EMbc
B-meson yields vs M()
12.4 ± 4.2 evts
“Sidebands”BKJ/
Non-resonantor “peaking bkgd
sidebands
Overlapregion
Cross-talk from BKJ/enhancement?
f dm = 0.75 ±0.14 evts
Check : signal yield for M(3 J/)= M X(3872) +1–3(no overlap with band) 12.4 evts 11.5 evts (expect 11.0 for no X-talk)
Other sidebands(no significant signals)
4.3 ±6.2 evts
6.4 ± 5.6 evts
Area of I and III each= 4x Area o signal bin
Non-res bkd in signal bin = 1.3 ± 1.0 evts
Branching fraction
Br(X J/)Br(XJ/)
Nev( J/) (2J/)Nev(J/)(3J/)
=
0.188
0.036
13.1 ± 4.2
62.6 ± 8.3
= 1.1 ± 0.4 (stat) ± 0.3 (syst)
Accept:ance: 10%Xtalk/Bkgnd: -20%X J/: +25%M(3)<750 MeV
significance ≈ 4
Consistent with sub-threshold X(3872) J/
• M + MJ/ = 3879 MeV (7 MeV above 3872)
– X J/ occur via virtual ’s, 3 masses cluster at the kinematic limit.
• (XJ/)/(X J/) = 1.1 ±0.4± 0.3
• In agreement with Swanson’s DD* bound-state model for the X(3872) [PLB 588,189 (2004)]
• Smoking gun for qqqq interpretation of X(3872)?- -
update continuum e+e-J/ (cc) with 287 fb-1
L=101 fb-1
2002L=155 fb-
1
2003
287 fb -1
c c0
‘c
4th peak!!non-zero continuumbelow DD threshold
• J/ J/ negligible
• confirm c’
• e+e-J/ (cc) > e+e-J/ glue
• (e+e-J/ c) > 10x theory
• evidence for c’ 2004
-
What is the 4th peak?the reconstruction and selection procedure is the same as before
Extend the fit regionno signal of X(3872)significant (>4) peak at M=3940 11 MeVN=14833 (4.5)the width is consistent w/ resolution (= 32 MeV)
X(3872)
c
c
c0
c‘
‘
What is it? c0? c ??‘ “
Look at e+e-J/ D(D(*))
•Reconstruct a J/ & a D•use D0K-+ & D+K-++
•Determine recoil mass
Look at M(DD(*))
DD*
DD
3940 MeV
9.9 ± 3.3 evts(4.5 )
4.1 ± 2.2 evts(2.1 )
c0 DD*‘
c DD“
What is this one?
• Too narrow to be the same as the J/ peak at 3940 MeV
• c0 or c most likely charmonium states
– DD* signal rules against c0
– Mass is a little low for c
• M(3S) would be ≈ 100MeV• can M(3S) > M(2S)
‘ “
“‘
Summary• c’ established M(2S)<M(1S)
• (X(3872)J/ = (X(3872) J/)– Good for molecules; bad for charmonium
• Broad near-threshold J/ peak– too broad for charmonium– Too light for cc-glue hybrid?– theshold interaction involving a J/ ?
• 4th peak seen in e+e- J/X– Evidence for it in DD* (rules out c0’)– If it is the c”, M(3S) > M(2S)
B-factory data
3 D 2??
h c??e+e-J/ “X”(3940)
“Y”(3940)J/
X(3872)+-0J/
M(K3) for signal bin
Events at M(3)=775 MeVKinematic limit would peak
here