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Heavy Quarkonium
Roman Mizuk, ITEP
RAS session at ITEP, 24 Nov 2009
c c
n(2S+1)LJ
n radial quantum number
J = S + LP = (–1)L+1 parity
C = (–1)L+S charge conj.
Charmonium LevelsM
ass
(M
eV
)
JPC
(2S+1)LJ
Open charm threshold (3770)
(4040)
(4160)
c
’c
J/
(4415)
(potential Models)
c2 c1 c0hchc
′
Mass
(M
eV
)
JPC
(2S+1)LJ
Open charm threshold (3770)
(4040)
(4160)
c
’c
J/
X Z Y
(4415)
Y(4140)
Y
(potential Models)
c2 c1 c0hchc
′
c c
n(2S+1)LJ
n radial quantum number
J = S + LP = (–1)L+1 parity
C = (–1)L+S charge conj.
Charmonium Levels
10 XYZ states
XYZ States
Outline
Charmonium
X(3872)
1- - states from ISR
3940 family
Z±
BottomoniumObservation of b
Search for Yb
Most of the XYZ from B-factories
+ BES, CDF, D0
e+e– → (4S)Ecms ~ 10.6 GeV
950 + 530 fb-1 in total
6th anniversary!
Phys.Rev.Lett.91 262001, (2003)
CP
Belle citation count
B→Xsγ
466
482
334
X(3872)
PRL91,262001 (2003)
X(3872) was observed by Belle in
B+ → K+ X(3872)′
→ J/ψ π+ π-
recent signals X(3872) → J/ψ π+ π-
X(3872)
Confirmed by CDF, D0 and BaBar.
pp collisions
PRL93,162002(2004)
arXiv:0809.1224 PRD 77,111101 (2008)
PRL103,152001(2009)
Mass & Width
M = 3871.55 0.20 MeV Γ < 2.3 MeV (90% C.L.)
Close to D*0D0 threshold:m = – 0.25 0.40 MeV.
Branching Fractions
Br(X J/ + -) > 2.5%
at 90%C.L.
Absolute Br? missing mass technique
B-
K
XccB
(4S)
PRL96,052002(2006)
reconstructonly
K+ momentum in B+ c.m.s.
Br(B+ X K+) < 3.210–4
Br(B+ X K+) Br(X J/ + -) =(8.10 0.92 0.66) 10-6
(8.4 1.5 0.7) 10-6
Radiative Decays & J/
CX(3872) = +
J/
X(3872) → J/ + - 0
subthreshold production of
+-0
hep-ex/0505037 PRL102,132001(2009)
Decay modes Br relative to J/+-
J/ 0.15 0.05
J/ 0.33 0.12
1.1 0.4
J/ 1.0 0.5
′ J/
CX(3872) = + C+- = – 1. Isospin (+-) = 12. L(+-) = 1
IJPC of 0
PRL96,102002(2006)
hep-ex/0505038
L=1
L=0
M (+-)
X(3872) → J/+- X(3872) → J/0
X(3872) → J/+-
M (+-) is well described by 0→+- (CDF: + small interfering →+- ).
Angular analyses by Belle and CDF excluded JP =
JPC = 1++ or 2–+
2–+ is disfavored by
JP = 1++ are favorite quantum numbers for X(3872).
0++, 0+-, 0-+,1-+ ,1+-, 1--, 2++, 2-- , 2+-,3--, 3+-
Spin & Parity
2–+ not excluded.
PRL98,132002(2007)
0++
1--
1++
2-+
1. Br(X → ′ γ) / Br(X → J/γ) ~ 3 multipole suppression2. Observation of D*0D0 decay centrifugal barrier at the threshold
PRL 97,162002(2006)
B K D0D00
6.4σ
X(3875) X(3872)?
B+& B0 D0D*0K4.9σ
347fb-1
PRD77,011102(2008)
B K D0D*0
605 fb-1
D*→Dγ
D*→D0π0
Flatte vs BW similar result: 8.8σ
arXiv:0810.0358
avr
New Belle vs. BaBar only ~2σ difference
1.4σ
3871.55 ± 0.2
X(3872) Experimental Summary
JPC = 1++ (2–+ not excluded)
Close to D*0D0 threshold: m = – 0.25 0.40 MeV.
Br(X(3872) J/ 0) > 2.5% (90% C.L.)
M = 3871.55 0.20 MeV , Γ < 2.3 MeV (90% C.L.)
Decay modes Br relative to J/ 0
J/ 0 1
J/ 1.0 0.5
J/ 0.17 0.05
1.1 0.4
D*0D0 ~10
3872
JPC = 1++ c1′
X(3872) is not conventional charmonium.
Is there cc assignment for X(3872)?
JPC = 2–+ η c2
Expected to decay into light hadronsrather than into isospin violating mode.
1++
2-+
Br( c1′ → J/ )Br( c1′ → J/ +-)
measure 0.170.05
expect 30
~100 MeV lighter than expected
[cq][cq]
Tetraquark?Maiani, Polosa, Riquer, Piccini; Ebert, Faustov, Galkin; …
No evidence for X–(3872) J/ –0 excludes isovector hypothesis
X(3872)–
M(J/π–π0) M(J/π–π0)
X(3872)–
PRD71,031501,2005
B0 B-
PRD71,014028(2005)
1. Charged partners of X(3872).2. Two neutral states ∆M = 8 3 MeV,
one populate B+ decay, the other B0.
Predictions:
Charged partner of X(3872)?
X(3872) Production in B0 vs. B+
No evidence for neutral partner of X(3872) in B0 decays.
B0→XK0s
5.9
M(J/)
2.3σ
M(J/)
arXiv:0809.1224 605 fb-1
PRD 77,111101 (2008) [413 fb-1]
MX = (2.7 ± 1.6 ± 0.4) MeV
Two overlapping peaks in J/ +- mode?
No evidence for two peaks m < 3.2 MeV at 90% C.L.
Tetraquarks are not supported by any experimental evidence for existence of X(3872) charged or neutral partners.
PRL103,152001(2009)
D*0D0 molecule?
MX = 3871.55 0.20 MeV(MD*0 + MD0) = 3871.80 0.35 MeV
Weakly bound S-wave D*0D0 system
Swanson, Close, Page; Voloshin; Kalashnikova, Nefediev; Braaten; Simonov, Danilkin ...
Bound state
J/+-D0D00
D*0D0
Virtual state
J/+-
D0D00
m = – 0.25 0.40 MeV
a few fm
Predict different line shapes for J/+- and D*0D0 modes:
D0D*0 molecule
Kalashnikova, Nefediev arXiv:0907.4901
Analysis of dataBound or virtual?c1 admixture?
~2 experimental difference reverses conclusion
Present statistics are insufficient to constrain theory?
Br(X(3872) J/ )Br(X(3872) J/ ) ~1
Large isospin violation due to 8 MeV differencebetween D*+D- and D*0D0 thresholds.
Br(X(3872) )Br(X(3872) J/ ) ~3
Similar ratio is expected for c1 decays c1 admixture?
State c1 admixture
Belle data bound ~ 30%
BaBar data virtual ~ 0
Large production rate in B decays and in pp c1 ?
theorists here should agree on the proper form & thenexperimenters should use it in a proper unbinned fit
There are other similar analyses which differ in the fit functions:
Braaten, StapletonZhang, Meng, Zheng
arXiv: 0907.31670901.1553
Br(B0 →XK*0) Br(X→J/ψπ+π–) < 3.4 10–6 at 90% C.L.
~90 events
Very weak K
*(892)
Br(BJ/ K*0)
Br(BJ/ KNR)~4
B → X(3872) K
arXiv:0809.1224 605 fb-1
X(3872) sideband
non-resonant Kπ
Mass(Kπ)
Br(B0 →X(K+π–)non_res) Br(X→J/ψπ+π–) = (8.1±2.0+1.1–1.4) 10–6
DD* molecular models for the X(3872) attribute its production& decays charmonium to an admixture of c1′ in the wave fcn.
But BKX(3872) is very different from BK charmonium.
BaBar PRD 71 032005
Belle arXiv 0809.0124
Belle arXiv 0809.0124
Belle PRD 74 072004
K′
KJ/
Kc1
Kc
Belle F.Fang Thesis
KX3872
M(K)
M(K)
M(K)
M(K)
M(K)
e+e– → 1–– final states via ISR
c
c
e-
s=E2cm-2EEcm
e+
e–
e+
1– –
ISR physics at B-factories Continuous ISR spectrum: access to the whole s interval em suppression compensated by huge luminosity
comparable sensitivity to energy scanning (CLEOc, BES)
Initial State Radiation
e+e– → γISR J/+– Y(4260), Y(4008)?
PRL 95 ,142001(2005)
233 fb-1
PRD74, 091104R (2006)
13.3 fb-15.4σ
PRL 96, 162003 (2006)
5.1σ
11σ(2S)
8σ
PRL 99, 182004 (2007)
550 fb-1
Y(4260)
Y(4008)7.4
Y(4260)
One or two states in e+e– → γISR J/+–?PRL 99, 182004 (2007)
550 fb-1
454 fb-1
preliminary
< 0.7 90% CL
7.5±0.9±0.8
Γee Br(J/+–), eV
Solution1 Y(4008) Solution2
Solution1 Y(4260) Solution2 Y(4008)
?
Y(4008)7.4
arXiv:0808.1543
Y(4260)
Y(4260)
e+e– → γISR +–
Y(4325) 8σ
Y(4660) 5.8
670 fb-1
PRL 99, 142002 (2007) PRL 98, 212001 (2007)
Y(4660) ?
Y(4325)
298 fb-1
Y(4360) Y(4660) 6.1σ
PRD78,014032(2008)
Combined fit
Only 1 unassigned 1– – cc level
Y(4660)
Y(4325)Y(4260)
Y(4008)
y(3
770)
Durham Data Base
Y(4
008)
y(4
040)
y(4
160)
Y(4
260)
Y(4
325) y
(441
5)
Y(4
660)
ψ(3
770)
Y(4
008)
ψ(4
040)
ψ(4
160)
Y(4
260)
Y(4
360) ψ
(441
5)
Y(4
660)
No evidence for Y 1-- → hadrons
X.H. Mo et al, PL B640, 182 (2006)
( → J/+-) = 0.104 ± 0.004 MeV (→ J/+-) = 0.044 ± 0.008 MeVMuch larger than measured
charmonium widths:
(Y(4260) → J/+-) > 0.508 MeV @ 90% CL
R(s
) =
– R
ud
s(
e+e– →
had
ron
s)(
e+e– →
μ+μ
– )
(e+e–→open charm)D*D*
DD*
ψ(4
040)
ψ(4
160)
Y(4
008)
ψ(4
415)
Y(4
660)
Y(4
260)
Y(4
360)
DD
DDπ
Λc+Λc
–
?
PRD77,011103(2008)
PRL100,062001(2008)
PRL98, 092001 (2007)
PRL101,172001(2008)
DD*π arXiv:0908.0231
0908.0231[hep-ex]
DD*πY(4260) ψ(4415)
9
/4260
4260*
JYBr
DDYBr
M(DD*)
Y(4260) is DD1 molecule/ccg hybrid? DD1 [→DD*π] decay should dominate but no signal found
Y(4008), Y(4260), Y(4360), Y(4660) don’t match peaks in D(*)D(*) Xsection
Y(4660) mass is close to Λc+Λc
– peak
ICHEP2008 Galina Pakhlova, ITEP
PRL 99,142002(2007)
ee→ΛΛ via ISR
PRD73,012005(2006)
ee→pp via ISR
PRL 99,142002(2007)
ee→ΛΛ via ISR
PRD73,012005(2006)
ee→pp via ISR
• no peak-like structure
• X(4630) = Y(4660) = = charmonium state 53S1 or 43D1 J.Segovia, A.M.Yasser, D.R.Entem, F.Fernandez
• Charmonium state 63S1 B.Q.Li and K.T.Chao
• Threshold effect E.Beveren, G.Rupp
•Y(4660) =ψ(2S)f0(980) bound state F.K.Gou,C.Hanhart, S.Krewald,U.G.Meissner
• Point-like baryons R.B.Baldini, S.Pacetti, A.Zallo
• X(4630) = Y(4660) D.V.Bugg
• X(4630) = Y(4660) = = tetraquark D.Ebert, R.N.Fausov, V.O. Galkin
• X(4630) ≡ Y(4660)? JPC=1– –
e+e–→Λc+Λc
– γISR
Phys.Rev.Lett.101,172001(2008) Interpretations for X(4630)
PRL 97, 242001 (2006)
6.2σ B–→Λc+p π–─
PRL 97, 242001 (2006)
6.2σ B–→Λc+p π–─
• dibaryon threshold effect?• like in B→pΛπ, J/ψ→γpp
DD DD* D*D*
DDπ
DD*π
Λ+c Λ–
c
Sum of all exclusive contributions
Only small room for unaccounted contributions• Charm strange final states
Limited inclusive data above 4.5 GeV• Charm baryons final states
States near 3940 MeV
States near 3940 MeV
M = 3942 +7 ± 6 MeV
tot = 37 +26 ±12 MeV
Nsig = 52 +24 ± 11 evts
-6
-15
-16
PRL 100, 202001
e+e- J/ DD*
M(DD*)M≈3940 ± 11 MeV≈ 92 ± 24 MeV
PRL94, 182002
M(J/)
BKJ/
M = 3929±5±2 MeV
tot = 29±10±2 MeV
Nsig = 64 ± 18 evts
DD
M(DD)
PRL 96, 082003
X(3940) Y(3940) Z(3930)
not seen in J/ not seen in DD* Probably the c2’probablydifferent
BaBar: PRL 101, 082001
M≈3914 ± 5 MeV≈ 33 ± 10 MeV
New peak in J/
X
M: 3914 3 2 MeV, : 23 10 +2 -8 MeV,
Nres = 55 14 +2 -14 events
Signif. = 7.7,
prel
imin
ary
Background only fit
The 4 states near 3940
X(3940)Y(3940)
Belle
Z(3930)
Mass(GeV)
This X(3915)
Width(GeV)
Range: ((stat.)(sys.))
Good overlap withBaBar “Y(3940)” values
c
c0
X(3940)c
Only JP=0- or 0+ charmonium is produced in pair with J/.
Radial excitations are not suppressed
e+e- → J/ + ccMissing mass technique
M = 3942 ±6 MeV
tot =37 ±12 MeV
+7−6
+26 −15
X(3940) → DD*
M= 4156 15 MeV
tot = 139 21MeV
+25−20
+111 −61
X(4160) → D*D*
M(DD*) M(D*D*)
Exclusive reconstruction of cc
Double charmonium production
cc assignments for X(3915), X(3940) & X(4160)?
3940MeV4160MeV
•Y(3915) = co’? (J/) too large?•X(3940) = c”? mass too low?•X(4160) = c’’’? mass way too low?
c
”
c’’’
3915MeVc0’
States decaying into J/
PRL102, 242002 (2009)
D*D*ssDD**ss molecule? molecule? [cs[cscscs] tetraquark?] tetraquark?
M = 4143.0 ± 2.9 ± 1.2 MeV
= 11.7+8.3-5.0 ± 3.7 MeV
Y(4140) J/ by CDFB+ Y(4140) K+
14±5 ev>3.8
21325
/
KJB
2sBEE J/ψM
Preliminary Preliminary 9.15.7 9.44.4
Br(B+→Y(4140)K+) Br(Y→J/)
CDF (9.0 ± 3.4 ± 2.9)10-6
Belle <6 10-6 at 90% CL
prel
imin
ary
M(X(4350))=4350.6+4.6-5.1± 0.7 MeV
Γ=13.3+17.9-9.1 ± 4.1 MeV
JP=0+: ΓγγBr(X(4350)) →J/) =6.4+3.1-2.3 ± 1.1 eV
JP=2+: ΓγγBr(X(4350)) →J/) =1.5+0.7-0.5 ± 0.3 eV
•No Y(4140)•Another structure:
Study of J/
825fb-1
8.8+4.2-3.2 ev
3.2-3.9
ucd
c
Z(4430)+ and Z1(4050)+ & Z2(4250)+
Smoking guns for charmed exotics:
K*(1430) → K+-
??
K*(892) → K+-
B → K ′
M2(K+-)
M2
(′+
)
The Z(4430)± ±’ peak
M(
±’)
Ge
V
BK +’
Z(4430)
M () GeV
evts near M(’)4430 MeV
M2
(
±’)
GeV
2
M2() GeV2
“K* Veto”
Shows up in all data subsamples
But…
BaBar doesn’t see a significant Z(4430)+
“For the fit … equivalent to the Belle analysis…we obtain mass
& width values that are consistent with theirs,… but only ~1.9from zero; fixing mass and width increases this to only ~3.1.”
Belle PRL: (4.1±1.0±1.4)x10-5
Reanalysis of Belle’s BK’ data using Dalitz Plot
techniques
2-body isobar model for K’
KZ+
K2*’
K*’
K’
Our default model
′
K*(890) ′
K*(1410) ′
K0*(1430) ′
K2*(1430) ′
K*(1680) ′
K Z+
Results with no KZ+ term
fit CL=0.1%
12
3 4
5
1 2 3 4 5
A
B
C
A B
C
Results with a KZ+ term
fit CL=36%
12
3 4
5
A B
C
1 2 3 4 5
A
B
C
Compare with PRL results
Signif: 6.4Published results
Mass & significance similar,width & errors are larger
With Z(4430)
WithoutZ(4430)
Belle: = (3.2+1.8+9.6 )x10-5 0.9-1.6
BaBar:
No big contradiction
K* veto applied
Systematics Z(4430)+ significance
The Z1(4050)+ & Z2(4250)+ +c1 peaks
PRD 78,072004 (2008)
Dalitz analysis of B0K-+c1
K*(
89
0)
K*(
14
00
)’s
K*(
16
80
)
K3*(
17
80
)
M (J) GeV
E GeV ???
BKc1 Dalitz-plot analyses
KZ+
K2*c1
K*c1
Kc1
Default Model
c1
K*(890)c1
K*(1410)c1
K0*(1430)c1
K2*(1430)c1
K*(1680)c1
K3*(1780)c1
KZ+
Fit model: all low-lying K*’s (no Z+ state)
a b
c d
e f
g
a b c d g
f
e
C.L.=310-10
Fit model: all K*’s + one Z+ state
a b
c d
e f
g
a b c d g
f
e
C.L.=0.1%
Are there two?
a b c d
? ?? ?
Fit model: all K*’s + two Z+ states
a b
c d
e f
g
a b c d g
f
e
C.L.=42%
Two Z-states give best fit
Projection with K* veto
Systematics of B0 → K- π+ c1 fit
Significance of Z1(4050)+ and Z2(4250)+ is high.
Fit assumes JZ1=0, JZ2=0; no signif. improvement for JZ1=1 &/or JZ2=1.
M=1.04 GeV; G=0.26 GeV
Bottomonium
Discovery of ηb
PRL 100, 06200 (2008)
non-peaking background subtracted
γISRχbJ
Y(3S)→γηb
10σ
120M Y120M Y(3S)(3S)
100M Y100M Y((22S)S)
χbJ
γISR
arXiv:0903.1124
Y(2S)→γηb
non-peaking background subtracted
ηb3.5σ
MeV8.19.9392 6.48.4
bM
MeV7.29.9388 1.33.2
bM
M(ηb) = (9390.4 ± 3.1) MeV/c2
M(Υ(1S)) - M(ηb) = 69.9 ± 3.1 MeV/c2
Theory ~ 60 MeV/c2
•Decay modes of ηb are not known
•Search for Y(3S), Y(2S)→γηb
with e+e → Υ(3S), Υ(2S) •Monochromatic line in photon energy spectrumProblem: peaking backgrounds
• Υ(nS) → χbJγsoft, χbJ → Υ(1S) γhard • e+e→ γISRΥ(1S)
Y(5S) & Y(6S)arXiv:0810.3829
7.9fb1
arXiv:0809.4120
3.9fb1
Both inclusive and exclusive dipion cross-sections are inconsistent with PDG Y(5S) &Y(6S) parameters
Energy scan above Υ(4S) to search for counterpart of Y(4260) in bottomonium sector: study cross section ofe+e → Υ(nS)π+π, (n=1, 2, 3)
Fit to inclusive cross section e+e→hadrons coherent Y(5S) +Y(6S) + continuum
(5S) ≠ Υb at 3 level
SummaryX(3872): at D*0D0 threshold, narrow, isospin violating mode is not suppressed.
1-- family: Y(4008), Y(4260), Y(4360), Y(4660) – no room in charmonium table, big (Y→ +-), no decays to hybrid favorite D**D
3940 family: X(3940), Y(3940), X(4160) – no clear charmonium assignment.
Z± family: Z(4430)+ confirmed with Dalitz analysis; observation of Z1(4050)+, Z2(4250)+ → c1+.
Yb: is not equal to (5S) at 3 level.b: observed.
or Y(4325)
or Y(3915)
Summary
In contrast”(3770) only above-open-charm threshold state with an established +-J/ mode
•Discovered 1977 (Lead Glass wall)
•2003 1st evidence for ”+-J/ (BESII)
•2006 ”+-J/ established (CLEOc)
Bf=(1.9+-0.3)x10-3; (+-J/) 50keV
~30 yrs later
PRL96, 082004 (2006)
PRB 605, 63 (2005)
Rapidis et al PRL39, 526 (1977)
~230 evts
~25 evts
3rd generation expt
Back-up
• In (4S) decays B are produced almost at rest.
• ∆E = Ei - ECM/2 Signal peaks at 0.
• Mbc = { (ECM/2)2 - (Pi)2}1/2 Signal peaks at B mass (5.28GeV).
∆E, GeV
Mbc, GeV
Reconstruction of B decays
B0J/ KS
Improvement to M(D0)?
iiKK
ii KEMME
S2
Best single measurement from CLEOc:
MD0 = 1864.847±0.150 (stat) ±0.095 (syst) MeV
CLEOc uses invariant mass:
large MD0
dominatesthe error
small 0not a bigcontrib.
& only uses D0KS(K+K-) decays:
i i
iiinv pEM 22 )()(
well known
±2x16keV±22keV
0.1 MD0
measured
Bf0.002319 evtsstat errordominates
M(D0) measurement @ BESIII
i
ibeambc pEM 22 )(
Use “beam constrained mass @ ”:
need toknow Ebeam preciselyUse backscattered laser beam at
the unused X-ing region to measureEbeam (&MD0) to better than ±100 keV
Approved, funded,& under construction
Interpretation of Y states
Y(4360) & Y(4660) are conventional charmonium with shifted masses Y(4360) = 33D1 , Y(4660) = 53S1
G.J Ding, J.J.Zhu, M.L.Yan, Phys.Rev.D77:014033 (2008) A.M.Badalyan, B.L.G.Bakker, I.V.Danilkin, Phys.Atom.Nucl.72:638-646,(2009)
43S1 ≠ ψ(4415) = 43D1(4661); Y(4360)=43S1(4389) , Y(4660)=53S1 (4614) or 43D1(4661)
J.Segovia, A.M.Yasser, D.R.Entem, F.Fernandez Phys.Rev.D78:114033,(2008).
Charmonium hybrids The lightest hybrid is expected by LQCD around 4.4 GeV The dominant decays Y(4260)→D(*)D(*)π, via virtual D**
Zhu S.L.; Close F.E.; Kou E. and Pene O.
Hadro-charmonium Specific charmonium state “coated” by excited light-hadron matter
S.Dubinskiy, M.B.Voloshin, A.Gorsky
Multiquark states [cq][cq] tetraquark Maiani L., Riquer V., Piccinini F., Polosa A.D.
DD1 or D*D0 molecules Swanson E.; Rosner J.L., Close F.E.
S-wave charm meson thresholds Lui X.
Formalism
B0 → c1K+-, c1 → J/, J/ → +-
described by 6 variables: M(c1), M(K), (c1), (c1), (J/), (J/)
Justification: efficiency is ~constant in (c1), (J/)
after integration over (c1), (J/) interference terms drop out.
Efficiency vs. (c1) Efficiency vs. (J/)
different parts
of Dalitz
plot
range = (0, 2) range = (0, 2)
perform Dalitz analysis w/o considering angular variables, assume no interference between different c1 helicity states.
Formalism (2)
Amplitude
, K*(892), K0(1430), K2(1430), K*(1680), K*3(1780),
Z+ → +c1
Fit function
Signal component
c1 helicity
Binned likelihood fit
(see next slide for details on amplitude of Z+)
E s.b.Efficiency
B meson and R resonance decay form-factors Angular part
Amplitude of Z
c1 rest frame
pK
p
c1 spin quantization axisin B → c1 K*(→K) decays
c1 spin quantization axisin B → Z(→c1) K decays
cosTransformation of basis vectors
The same relation for amplitudes
Comparison with BaBar
BaBar paper: Belle and BaBar data are statistically consistent.
peak in M(π+ψ) is present also in BaBar data with similar to Belle shape:
BaBarBelle
Comparison with BaBar
BaBar paper: Belle and BaBar data are statistically consistent.
peak in M(π+ψ) is present also in BaBar data with similar to Belle shape:
BaBarBelle
Why different significances are reported? (6.4σ Belle vs. 1.9–3.1σ BaBar)
assumption about background is crucial.
BaBar method is a simplification of amplitude analysis with a lot of (unphysical?) freedom in description of background.
Dalitz analysis is preferable.
Result of Dalitz fitscaled down by 1.18 to account for smaller statistics @ BaBar.
• Z(4430)+ signal in BK’ persists with a more complete amplitude analysis.– signif. ~6, product Bf ~3x10-5 (with large errors)
• No significant contradiction with the BaBar results – signif. = 2~3, Product Bf<3x10-5
• Z1(4050) & Z2(4250), seen in BKc1, have similar properties (i.e. M & ) & product Bf’s– signif. (at least one Z+)>10; (two Z+ states)>5
Summary on Z±