Transcript Hidden charm spectroscopy from B

Bottomonium and bottomonium–like states
Alex Bondar
On behalf of Belle Collaboration
Cracow Epiphany Conference “Present and Future B-physics”
(9 - 11, January, 2012, Cracow, Poland )
1
Outline
(5S) 
Zb(10610)+ 
+
Zb(10650) 
(1S)+ (2S)+ (3S)+ hb(1P)+ -  b(1S) + hb(2P)+ -
at BB* and B*B* thresholds  molecules
Observation of hb(1P) and hb(2P)
Observation of Zb
final state w/ hb(nP) and (nS)
angular analysis
Observation of hb(1P) b(1S)
arXiv:1103.3419
accepted by PRL
arXiv:1110.2251
accepted by PRL
arXiv:1105.4583
arXiv:1110.3934
2
Anomalous production of (nS) +PRL100,112001(2008)
(MeV)
PRD82,091106R(2010)
line shape
of Yb
102
(5S)
Simonov JETP Lett 87,147(2008)
1. Rescattering (5S)BB(nS)?
2. Similar effect in charmonium?
Y(4260) with anomalous (J/ +-)
 assume  Yb close to (5S)
to distinguish  energy scan
 shapes of Rb and () different (2)
3
Observation of
hb(1P) & hb(2P)
4
Trigger
CLEO observed e+e- → hc +– @ ECM=4170MeV
(hc +–)  (J/ +–)
PRL107, 041803 (2011)
Y(4260)
Hint of rise in (hc+-)
@ Y(4260) ?
4260
Y(4260)Yb  search for hb(nP)+- @ (5S)
5
Introduction to hb(nP)
_
(bb) : S=0 L=1 JPC=1+Expected mass
 (Mb0 + 3 Mb1 + 5 Mb2) / 9
MHF  test of hyperfine interaction
For hc MHF = 0.00  0.15 MeV,
expect smaller deviation for hb(nP)
Previous search
arXiv:1102.4565
PRD 84, 091101
BaBar
3.0
(3S) → 0 hb(1P)
MM(+-)
6
Introduction to hb(nP)
_
(bb) : S=0 L=1 JPC=1+Expected mass
 (Mb0 + 3 Mb1 + 5 Mb2) / 9
MHF  test of hyperfine interaction
For hc MHF = 0.00  0.15 MeV,
expect smaller deviation for hb(nP)
Previous search
arXiv:1102.4565
PRD 84, 091101
BaBar
3.0
(3S) → 0 hb(1P)
MM(+-)
7
(5S)  hb +- reconstruction
hb → ggg, b (→ gg)  no good exclusive final states
reconstructed
“Missing mass”
M(hb) = (Ec.m. – E*+-)2 – p+* 2  Mmiss(+-)
(1S)
hb(1P) (2S) hb(2P) (3S)
8
Results
121.4 fb-1
Significance w/
systematics
hb(1P) 5.5
hb(2P) 11.2
9
Hyperfine splitting
Deviations from CoG (Center of Gravity) of bJ masses
hb(1P) (1.7  1.5) MeV/c2 consistent with zero, as expected
2
hb(2P) (0.5 +1.6
-1.2 ) MeV/c
Ratio of production rates
spin-flip
=
for hb(1P)
for hb(2P)
no spin-flip
Process with spin-flip of heavy quark is not suppressed
 Mechanism of (5S)  hb(nP) +- decay violates
Heavy Quark Spin Symmetry
10
Resonant structure of
(5S)hb(nP)
+
 
11
M(hb–), GeV/c2
Resonant structure of (5S)  hb(1P) +phase-space MC
M(hb+), GeV/c2
12
phase-space MC
fit Mmiss(+–)
in M(hb) bins 
hb(1P) yield / 10MeV
M(hb–), GeV/c2
Resonant structure of (5S)  hb(1P) +121.4 fb-1
M(hb+), GeV/c2
 Zb(10610), Zb(10650)
M(hb), GeV/c2
Fit function
_
Results
MeV/c2 ~BB* threshold
M1 =
1 =
MeV
a=
_
18 (16 w/ syst)
MeV/c2 ~B*B* threshold
M2 =
2 =
Significance
MeV
non-res.~0
=
degrees
13
phase-space MC
fit Mmiss(+–)
in M(hb) bins 
hb(1P) yield / 10MeV
M(hb–), GeV/c2
Resonant structure of (5S)  hb(2P) +121.4 fb-1
M(hb+), GeV/c2
hb(1P)+M1 =
1 =
M2 =
2 =
hb(2P)+MeV/c2
MeV/c2
MeV
MeV
MeV/c2
MeV/c2
MeV
MeV
Significances
6.7 (5.6 w/ syst)
a=
=
M(hb), GeV/c2
degrees
non-res.~0
degrees
non-res. set to zero
14
Resonant structure of
(5S)(nS)
+
 
(n=1,2,3)
15
(5S)  (nS) + +-
(n = 1,2,3)
(3S)
(2S)
(1S)
reflections
Mmiss (+-), GeV/c2
16
(5S)  (nS) + +-
(n = 1,2,3)
purity 92 – 94%
(3S)
(2S)
(1S)
Mmiss (+-), GeV/c2
17
(5S) (nS) +- Dalitz plots
(1S)
(2S)
(3S)
18
(5S) (nS) +- Dalitz plots
(1S)
(2S)
(3S)
 Signals of Zb(10610) and Zb(10650)
19
Fitting the Dalitz plots
Angular analysis favors JP=1+
(5S)  Zb, Zb  (nS) – no spin orientation change
Non-resonant heavy quark spin-flip amplitude is suppressed
Spins of (5S) and (nS) can be ignored
Signal amplitude parameterization:
S(s1,s2) = A(Zb1) + A(Zb2) + A(f0(980)) + A(f2(1275)) + ANR
ANR = C1 + C2∙m2(ππ)
Parameterization of the non-resonant amplitude is discussed in
[1] M.B. Voloshin, Prog. Part. Nucl. Phys. 61:455, 2008.
[2] M.B. Voloshin, Phys. Rev. D74:054022, 2006.
A(Zb1) + A(Zb2) + A(f2(1275))
– Breit-Wigner
A(f0(980))
– Flatte
20
Results: (1S)π+πsignals
M((1 S)π+), GeV
reflections
M((1S)π-), GeV
21
Results: (2S)π+πsignals
reflections
M((2S)π+), GeV
M((2S)π-), GeV
22
Results: (3S)π+π-
M((3S)π+), GeV
M((3S)π-), GeV
23
Summary of Zb parameters
Average over 5 channels
 M1  = 10607.22.0 MeV
 1  = 18.42.4 MeV
 M2  = 10652.21.5 MeV
 2  = 11.5  2.2 MeV
24
Summary of Zb parameters
Average over 5 channels
 M1  = 10607.22.0 MeV
 1  = 18.42.4 MeV
o
 = 180
 M2  = 10652.21.5
MeV
 = 0o
hb(1P) yield / 10MeV
 2  = 11.5  2.2 MeV
M(hb), GeV/c2
Zb(10610) yield ~ Zb(10650) yield in every channel
Relative phases: 0o for  and 180o for hb
25
Angular analysis
26
Angular analysis
Definition of angles
i (i,e+), [plane(1,e+), plane(1, 2)]
Example : (5S)  Zb+(10610) -  [(2S)+] -
non-resonant
cos1
combinatorial
cos2
, rad
Color coding: JP= 1+ 1- 2+ 2- (0 is forbidden by parity conservation)
Best discrimination: cos2 for 1- (3.6) and 2- (2.7);
cos1 for 2+ (4.3)
27
Summary of angular analysis
All angular distributions are consistent with JP=1+
for Zb(10610) & Zb(10650).
All other JP with J2 are disfavored at typically 3 level.
Probabilities at which different JP hypotheses are disfavored compared to 1+
Preliminary:
procedure to deal with non-resonant contribution is approximate,
no mutual cross-feed of Zb’s
28
Heavy quark structure in Zb
A.B.,A.Garmash,A.Milstein,R.Mizuk,M.Voloshin PRD84 054010 (arXiv:1105.4473)
Wave func. at large distance – B(*)B*
1 - - 1- '
Z


- 1
Qq
b
0
Qq
bb 0
bb1
2
2
1 - - 1- Z


 1
Qq
b
0
Qq
bb 0
bb1
2
2
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
–”–
Predicts
• Existence of other similar states
Other Possible Explanations
• Coupled channel resonances (I.V.Danilkin et al, arXiv:1106.1552)
• Cusp
(D.Bugg Europhys.Lett.96 (2011),arXiv:1105.5492)
• Tetraquark
(M.Karliner, H.Lipkin, arXiv:0802.0649)
29
Observation of
hb(1P)b(1S) 
30
Introduction to b
Expected decays of hb
Godfrey & Rosner, PRD66 014012 (2002)
hb(1P) → ggg (57%), b(1S) (41%), gg (2%)
hb(2P) → ggg (63%), b(1S) (13%), b(2S) (19%), gg (2%)
Large hb(mP) samples give opportunity to study b(nS) states.
(3S)  b(1S) 
Experimental status of b
M[b(1S)] = 9390.9  2.8 MeV (BaBar + CLEO)
M[(1S)] – M[b(1S)] = 69.3  2.8 MeV
pNRQCD: 4114 MeV
Lattice: 608 MeV
Kniehl et al., PRL92,242001(2004)
Meinel, PRD82,114502(2010)
Width of b(1S): no information
31
Method
Decay chain
+
(5S)  Zb  hb (nP)
+
 b(mS) 
reconstruct
Use missing mass
to identify signals
MC simulation
true +fake 
M(b)
fake +true 
true +true 
M(hb)
32
Method
Decay chain
+
(5S)  Zb  hb (nP)
+
 b(mS) 
reconstruct
Use missing mass
to identify signals
MC simulation
true +fake 
M(b)
fake +true 
Mmiss(+- ) 
Mmiss(+-) – Mmiss(+-) + M[hb]
true +true 
M(hb)
33
Method
Decay chain
+
(5S)  Zb  hb (nP)
+
 b(mS) 
reconstruct
Use missing mass
to identify signals
MC simulation
Mmiss(+- ) 
Mmiss(+-) – Mmiss(+-) + M[hb]
M(b)
Approach:
fit Mmiss(+-) spectra
in Mmiss(+-) bins
M(hb)
 hb(1P) yield vs. Mmiss(+-)
 search for b(1S) signal
34
Results
b(1S)
N.Brambilla et al., Eur.Phys.J.
C71(2011) 1534 (arXiv:1010.5827)
pNRQCD
Lattice
13
BaBar
(3S)  b(1S) 
BaBar (2S)
CLEO (3S)
2
MHF [b(1S)] = 59.3  1.9 +2.4
–1.4 MeV/c
BELLE preliminary
potential models :  = 5 – 20 MeV
Godfrey & Rosner : BF = 41%
35
Summary
First observation of hb(1P) and hb(2P)
Hyperfine splitting consistent with zero, as expected
Anomalous production rates
arXiv:1103.3419
accepted by PRL
Observation of two charged bottomonium-like resonances in 5 final states
(1S)π+, (2S) π+, (3S)π+, hb(1P)+, hb(2P)+
M = 10607.2  2.0 MeV
M = 10652.2  1.5 MeV
Zb(10610)
Zb(10610)
 = 18.4 2.4 MeV
 = 11.5  2.2 MeV
arXiv:1105.4583,
arXiv:1110.2251,
accepted by PRL
Masses are close to BB* and B*B* thresholds – molecule?
Angular analyses favour JP = 1+ , decay pattern  IG = 1+
Observation of hb(1P)b(1S)
arXiv:1110.3934
The most precise single meas., significantly different from WA,
decreases tension w/ theory
Will Zb’s become a key to understanding of all other quarkonium-like states?
36
Back up
37
arXiv:1105.5829
12GeV
1 1 Z b' 


0 1 2 1bb 0Qq
2 bb Qq
1 1 Zb 


 0Qq
0
1
bb
bb 1Qq
2
2
3 1 Wb'0  0bb  0Qq - 1bb 1Qq
2
2
Wb 0
Wb'1
1 3  0bb  0Qq  1bb 1Qq
2
2
 (1bb 1Qq ) J 1
-
11.5GeV
U(6S)

r
w
U
hb 
br

Uw
b
w

Zb
1+(1+)

r
r
w
Ur
b


0-(1+)
U(5S)
-
Wb 2  (1bb 1Qq ) J  2
U
bw
U(?S)
Uw
Ur
Uw
BB*
Ur
Wb0
Xb Wb1
0+(0+) 1-(0+)
0+(1+) 1-(1+)
B*B*
Wb2
0+(2+) 1-(2+) 0-(1-)
BB
IG(JP)
38
1 
0
bb 1Qq
2
1 Zb 


0
bb 1Qq
2
Z b' 
1 
1 0Qq
2 bb
1 
1 0Qq
2 bb
'
b0
W
Wb 0
3 1  0bb  0Qq - 1bb 1Qq
2
2
1 3  0bb  0Qq  1bb 1Qq
2
2
39
Coupled channel resonance?
I.V.Danilkin, V.D.Orlovsky, Yu.Simonov arXiv:1106.1552
No interaction between B(*)B* or  is needed to form resonance
No other resonances predicted
B(*)B* interaction switched on 
individual mass in every channel?
40
Cusp?
D.Bugg Europhys.Lett.96 (2011) (arXiv:1105.5492)
Amplitude
Line-shape
Not a resonance
41
Tetraquark?
M ~ 10.2 – 10.3 GeV
Ying Cui, Xiao-lin Chen, Wei-Zhen Deng,
Shi-Lin Zhu, High Energy Phys.Nucl.Phys.31:7-13, 2007
(hep-ph/0607226)
M ~ 10.5 – 10.8 GeV
Tao Guo, Lu Cao, Ming-Zhen Zhou, Hong Chen, (1106.2284)
M ~ 9.4, 11 GeV
M.Karliner, H.Lipkin, (0802.0649)
42
Selection
Decay chain
+
(5S)  Zb  hb (nP)
+
reconstruct
 b(mS) 
R2<0.3
Hadronic event selection; continuum suppression using event shape; 0 veto.
Require intermediate Zb : 10.59 < MM() < 10.67 GeV
bg. suppression 5.2
Zb
43
Mmiss(+-) spectrum
requirement of intermediate Zb
Update of M [hb(1P)] :
MHF [hb(1P)] = (+0.8  1.1)MeV/c2
(2S)
3S1S
hb(1P)
Previous Belle meas.:
arXiv:1103.3411
MHF [hb(1P)] = (+1.6  1.5)MeV/c2
44
Results of fits to Mmiss(+-) spectra
hb(1P) yield
b(1S)
Peaking background?
MC simulation  none.
(2S) yield
no significant
structures
Reflection yield
45
Calibration
+
Use decays B  c1 K+  (J/ ) K+
Photon energy spectrum
MC simulation
hb(1P)  b(1S) 
c1  J/ 
cosHel > – 0.2
cosHel (c1)> – 0.2  match  energy of signal & callibration channels
46
Calibration (2)
Resolution: double-sided CrystalBall function with asymmetric core
data
E s.b. subtracted
M(J/), GeV/c2
 Correction of MC
mass shift
fudge-factor
for resolution
–0.7  0.3 +0.2
–0.4 MeV
1.15  0.06  0.06
47
Integrated Luminosity at B-factories
(fb-1)
asymmetric e+e- collisions
> 1 ab-1
On resonance:
(5S): 121 fb-1
Bs (4S): 711 fb-1
(3S): 3 fb-1
(2S): 24 fb-1
(1S): 6 fb-1
Off reson./scan :
~100 fb-1
530 fb-1
On resonance:
(4S): 433 fb-1
(3S): 30 fb-1
(2S): 14 fb-1
Off reson./scan :
~54 fb-1
48
e+e- hadronic cross-section
BaBar PRL 102, 012001 (2009)
(1S)
(5S)
(6S)
(4S)
(2S)
(3S)
(4S)
Belle took data at
E=10867 1 MэВ
2M(B)
2M(Bs)
_
e+ e- ->(4S) -> BB, where B is B+ or B0
_
_
_
_
_
e+ e- -> bb ((5S)) -> B(*)B(*), B(*)B(*), BB, Bs(*)Bs(*), (1S)  ,  X …
main motivation
for taking data at (5S)49
Description of fit to MM(+-)
Three fit regions
Example of fit
Residuals
2
3
BG: Chebyshev polynomial, 6th or 7th order
Signal: shape is fixed from +-+- data
“Residuals” – subtract polynomial from data points
KS contribution: subtract bin-by-bin
M(+-)
(1S)
1
kinematic
boundary
Ks generic
(3S)
50
MM(+-)
MM(+-)
Results: Y(5S)→Y(2S)π+π-
51
Results: Y(5S)→Y(2S)π+π-
52