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Exotic Hadron Spectroscopy at B-factories
Toru IijimaKobayashi-Maskawa Institute
Nagoya University
KMI Topics SeminarMarch 11, 2015
About Me1987-1994: Kyoto University
H dibaryon search KEK-E176 A-dependence of (K-,K+) BNL-E813/E836
1994-2002: KEK, 2002-now: Nagoya University
B factory Super B factory Particle ID (Cherenkov detectors) CP violation Rare decays Hadron physics
「新ハドロン」新学術領域( 2009~ )
KEK-E176
BNL-E813/836
Belle 実験
dc
uc
KEK-E176/E224
Hadron spectroscopy is one of my favorite subjects 2
d s
u u
d s
Confirmation of Kobayashi-Maskawa
B0 tag_B
0 tag
March 5, 2014 Colloquium at University of Cincinnati 3
Press release from the Academy
“As late as 2001, the two particle detectors BaBar at Stanford, USA and Belle at Tsukuba, Japan, both detected broken symmetries independently of each other. The results were exactly as Kobayashi and Maskawa had predicted almost three decades earlier. “
4
Quest in low-energy QCDAre there exotics beyond meson(qq) /baryon (qqq) ?
QCD just require hadrons to be colorless, and allow exotics.
Such exotic states exist ?
New Hadrons ( Exotics )Tetra-quark Penta-quark Molecule
q q
qq q
meson baryonOrdinal Hadrons
6 quark modelc tu
d s b
up
down
charm
strange
top
bottom
I II IIIq=u, d, s, c, b, t
flavor
color (R,G,B )
Sakata Model(p, n, L)
Gell-Mann(u,d,s)
Gell-Mann 1964
5
Existence of such exotics have long been discussed since the birth of the quark model.
Discoveries in 1974 Discovery of J/y
SLAC, Burton Richter et al. BNL, Samuel Ting et al.
6
c c
And following qurkonium spectroscopy established physical existence of quarks and qq picture of mesons.
Discoveries at B-factories
• temp
7
hc’ & e+e-ccccD0*0 & D1*0
X(3872)
Sc* baryon triplet
X(3940), Y(3940)
cc2’
Y(4660) Y(4008)
DsJ(2700)Xcx(3090)
Z(4430)
DsJ(2317/2460)
DsJ(2860)
Y(4260)
Y(4320)
Integ
rated L
um
inosity Neutral
uc
uc
dc
uc
u u
c c
cc
g
Hybrid
clusterTetraquark
Observed >15 Exotic resonances
X(3915), Y(4350)Z(4050),Z(4250)
Charged
New resonances discovered at B-Factories Zb(10610),Zb(10650)
Yb
Zb0
hb
Z(3885)
hb(2S)
e+ source
Ares RF cavity
Belle detectorSCC RF(HER)
ARES(LER)
The KEKB Collider e- (8.0GeV) × e+ (3.5GeV)
⇒U(4S) →BB⇒Lorentz boost:
bg = 0.425 Finite crossing angle
- 11mrad ×2 Operated 1999-2010
Peak luminosity
2.1 x 1034 cm-2s-1 !
2010/10/29 8Toru Iijima, seminar at Konan
9
Luminosity at B Factories
@ Belle
Belle Detector Acceptance: 0.9 ×4p Vertex resolution
s(J/y ll) ~75nm Momentum resolution
s(Pt) = 0.19 ・ Pt 0.34/b %
Energy resolution
s(Eg)/Eg =1.8% @ 1GeV Particle ID
e, , m p, K, p Minimum bias trigger
Evis >= 1GeV & Ntrk >= 2
& Ncluster >= 4
essentially no loss for BB.
10
Production of cc in B Factories
11
B factories can produce charmonium (-like) states in four ways.
Chamonium-like Exotics
12
Discovery of X(3872)2003, by Belle
X (3872)Discovery by Belle in 2003, followed by D0, CDF, BaBar.
14
And more recently also by LHCb, CMS
BK J/ypp
’y
X(3872)
M(D0)+M(D*0)=3871.84 +/- 0.20PDG2012: M=3871.68 +/- 0.17
What is X(3872) ?• PDG2014
– mass M = 3871.69 ± 0.17 MeV– Width Γ < 1.2 MeV (90%C.L.)
• The observed mass is – different from that predicted by conventional charmonium
picture.– Very close to M(D0) + M(D*0) = 1864.84 + 2006.96 =
3871.80 MeV
• The width is very narrow
c
u
cu
πc
u
c
uu
cuccu
π
D(*)D(*) Molecule
cuc ucuu
cc u
Tetraquark
“Di-quark”
N. A. Tornqvist, PLB590.209 (2004)
Belle found Z(4430)+ in BK p+ y’ decays. One-dimensional fit on y’p+ distribution after
K*(890) /K*(1430) vetos.
Confirmed by analysis with a full Dalitz plot.
Belle found also another two states, Z(4050)+ & Z(4250)+, in BK p+ cc1 decays.
Z(4430)+, Z (4050)+, Z(4250)+ by Belle
16
M2(ψ’π+)
PRD80, 031104(2009)
PRD80, 031104(2009)
Their minimum quark content must be exotic:
Z(4430) at LHCb
• Observation of Z(4430)+
– Confirmed the Belle result
– JP=1+
LHCB-PAPER-2014-014
17
Update of Y(4260)/Y(4008) Updated measurement for e+e- → p+p-J/y w/ initial state
radiation (ISR) using full Belle data sample (967fb-1).
Two resonances; Y(4008) and Y(4260) are observed, consistent with the previous Belle measurement.
Resonance parameters
PRL110.252002(2013)18
Z(3895)+
Dalitz plot of M2(p+p-) and M2(pJ/y) for 4.15 < M(ppJ/y) < 4.45 GeV/c2.
Similar state also seen by BES III
A structure is observed in the M(pJ/y) mass with 5.2 s significance. • Mass = 3894.5 ± 6.6 ± 4.5 MeV/c2
• Width = 63 ± 24 ± 26 MeV/c2
A new charged charmonium-like state !
PRL110.252002 (2013)
M(p+p-) [GeV/c2] M(p+ J/y) [GeV/c2] M(p- J/y) [GeV/c2]
PRL110.252001(2013)
19
Bottomonium-like Exotics
20
Yb: Y(4260) counter part
21
Anomalously large rates(5S) → (nS) p+p- ~100 times larger than(1-4S) → (nS) p+p-
Large rate ofY(4260) → J/y p+p-
Peak locations areDifferent ?
Hadrons
22
Anomalies in (5S) decay
(3S)hb(2P)
hb(1P)
(2S)
(1S)
b(2S)
b(1S)
(4S)
(10860)
(11020)
JPC = 0 -+1+-1 --
9.50
9.75
10.00
10.25
10.50
10.75
11.00
Mass
, G
eV
/c2 2M(B)
260
430
290 6
1
2
partial (keV) (5S) hb(1,2P) +– are not suppressed
spin-
flipExpect suppression QCD/mb
Heavy Quark Symmetry Violation
[(5S) (1,2,3S) +–] >> [(4,3,2S)
(1S) +–] Belle PRL100,112001(2008)
hb production
Belle PRL108,032001(2012)
hb(1P)hb(2P)
+–
330
190
23
Anomalies in (5S) decay
(3S)hb(2P)
hb(1P)
(2S)
(1S)
b(2S)
b(1S)
(4S)
(10860)
(11020)
JPC = 0 -+1+-1 --
9.50
9.75
10.00
10.25
10.50
10.75
11.00
Mass
, G
eV
/c2 2M(B)
260
430
290 6
1
2
partial (keV) (5S) hb(1,2P) +– are not suppressed
spin-
flipExpect suppression QCD/mb
Heavy Quark Symmetry Violation
–
+
+Zb hb production via intermediate charged states Zb
hb (1P, 2P) p+ p-
24
Two peaks at the positions same as (nS)p+p-
to look at hb p+
Fit with
hb(1P) p+ hb(2P) p+
Charged Bottomonium-like Zb+ in (nS)p+
25
Two resonances: Zb+(10510), Zb
+(10560)
(1S) (2S) (3S)
Two peaks at the same positions in the 3 modes.
Zb(10610) & Zb(10650)
26
M=10608.42.0 MeV
=15.62.5 MeVM=10653.21.5 MeV
=14.43.2 MeV
Molecular Explanation of Zb+
27
d
bA
u
b π
B*
0
B-
d
bA
u
b π
B*
0
B*-
Zb+(10510) Zb
+(10560)
If Zb+ is B*B(*) molecule, it should decay into B*B(*)…
Bondar et al, PRD84,054010(2011)
Proximity to thresholds favors molecule picture
Each of them is mixture of spin triplet and singlet bb
This model explains
• Why hb is unsuppressed relative to
• Relative phase ~0 for and ~1800 for hb
• Production rates of Zb(10610) and Zb(10650) are similar widths
Final Remarks
28
29
New Resonances by Belle
Charm Flavor Region
2003~2009.8(15 states)2009.8~(11 states)
Resonance Spectrum discover by BelleΥ(5S)
Υ( 4 S)
Bottom Flavor Region
X(3
825)
Z(3
885)
+
hb(
2S) Z
b0
Z(4
200)
+
30
XYZ at B Factories
31
State Mass (MeV) Width (MeV) Decay Production
Ys(2175) 2175±8 58±26 ff0 ISR
X(3872) 3871.84±0.33 <0.95 J/ypp, J/yg B decay
X(3872) 3872.8 +0.7/-0.6 3.9 +2.8/-1.8 D*0D0, J/yw B decay
Y(3915) 3915±4 17±10 J/yw gg
Z(3940) 3929±5 29±10 DD gg
X(3940) 3942±9 37±17 DD* Double-charm
Y(3940) 3942±17 87±34 J/yw B decay
Y(4008) 4008 +82/-49 226 +97/-80 J/ypp ISR
Z(4051)+ 4051 +24/-43 82 +51/-28 pcc1 B decay
X(4160) 4156±29 139 +113/-65 D*D* Double-charm
Z(4248)+ 4248 +185/-45 177 +320/-72 pcc1 B decay
Y(4260) 4264±12 83±22 J/ypp ISR
X(4350) 4350 +4.7/-5.1 13 +18/-14 J/yf gg
Y(4350) 4361±13 74±18 y’pp ISR
Z(4430)+ 4433±5 45 +35/-18 y’p B decay
Y(4660) 4664±12 48±15 y’pp ISR
Yb(10890) 10889.6±2.3 54.7 +8.9/-7.6 ppΥ(nS) e+e- annihilation
Zb(10610) 10608.4±2.0 15.6±2.5 (Υ(nS) or hb) p Υ(5S) /Yb decay
Zb(10650) 10653.2±1.5 14.4±3.2 (Υ(nS) or hb) p Υ(5S) /Yb decay
c
u
cu
πc
u
c
uu
cuccu
π
cuc ucuu
cc u
cc
gccc
g
Tetraquark
Hybrid
D(*)D(*) Molecule
“Di-quark”Light
quark
charm
bottom
International CooperationSuper-KEKB J-PARCLEPS2
GSI/FAIR
LHC BEPCII
J-LAB
JLAB
RHIC
Charmonium-like Spectroscopy
33Conventional quark model describes only part of hadronic states.
4
3S
QCDV krr
Below DD thresholdwell understood by
Above DD threshold
?DD
DD*
New Quark Model ? Conventional quark model does
not work for excited states.D.O.F. = “constituent quark”
Can we build a new (extended) quark model ?D.O.F. = quasi-particle ?
34
Di-quark Colored meson
“New Nagoya Model ?”
Hot Region ?
35
Impact in the Universe History ?
cf. 12C Hoyle state ( 0+ triple-alpha) William Alfreed Fowler Nobel prize in physics 1983
Summary Exotic hadron spectroscopy is very hot topics.
Experimentally, it has been and will be very productive.
The real value is unknown (honestly speaking), although I “believe” it is significant.
KMI is a good place to discuss Collaboration between exp. – theory is essential. Link to the universe development ???
New data InterpretationModel
PredictionVerification
TheoryExp.
Thank you !
X(3872)/Z(4430) at LHCb• B+ →X(3872)K+, with X(3872)→J/y(mm)p+p- JPC = 1++
• Evidence for the decay X(3872)→y(2S) g
• Observation of Z(4430)+
– Confirmed the Belle result
– JP=1+
PRL110, 222001 (2013)
LHCB-PAPER-2014-014
LHCB-PAPER-2014-008
39
40
Study of Zb→B*B(*)
For the ϒ(5S) →B*B(*) + channel:Fully reconstruct one B meson in five exclusive decay
modes.
Look at recoil mass of B (for missing B) rM(B)
and of the pion (for two B combination) rM().
_
41
Clear BB* and B*B* signals
Mmiss(B)BB*
B*B*
BB BB* + BB*
B*B*
significance
9.35.7
Full reconstruction of one B in 5 modes
BBM(B)
121.4 fb-1
<0.60 % at 90% C.L.(4.25 0.44 0.69) %(2.12 0.29 0.36) %
preliminaryBF[ (5S) B(*)B(*) ]
_
_
_
_
___
__
_ _
Select two peaks
recoil mass
42
Observation of ZbBB* and Zb’B*B*M (BB*)
M (B*B*)
Zb’
6.8
phsp
Zb
8
phsp
Zb’ ? Molecule admixture of BB* in Zb’ is small
_
Zb’ BB* is suppressed w.r.t. B*B*despite larger PHSP
_ __
_
arXiv:1209.6450
Assuming Zb decays are saturated by these channels:preliminary
43
Fit (2S)00 structureDalitz plot analysis
with Zbs without
o Clear Zb0 signals are seen in (2S)π0π0
o Significance of Zb0(10610) is 5.3σ (4.9σ with systematics)
o Zb0(10650) is less significant (~2σ)
o Fit gives M(Zb0(10610) ) =10609±8±6 MeV
cf: M(Zb+)=10607.2±2.0 MeV
arXiv:1207.4345
H-dibaryon Search
44
(1S, 2S) decays World largest data samples
[PRL 110, 222002(2013)]
Jaffe, PRL 38, 195 (1977)
hypernucleus
tri-diquark
Doubly-Charmed Hadrons (C=-2) ? Doubly charmed baryons Xcc
+(ccd), Xcc++(ccu) have not been
established. Evidence reported by SELEX at FNAL, but not confirmed by
BaBar/Belle.
Tcc (udcc, spin=1) predicted to be stable against strong decay (S. H. Lee, S. Yasui); B.E. = M(Tcc) – M(D) – M(D*) = -79MeV.
Qcs(uudsc), Hc (qqqqqc) are also interesting.
Good chance also for bottom counterpart.
Belle has seen large double charm production.
Possible decay modes:
45
Xcc Search w/ Full Belle DataY. Kato, T. Iijima et al.,PRD89, 052003 (2014)
46
Charmed Strange Bayons Xc
47
First observation of Xc(3055)0 !
980 fb-1
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