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Z(4430) and related results at Belle. Outline Observation of Z + (4430)→ ψ ’ π + in B→ ψ ’ π + K decays Z(4430) interpretation within 4-quark model Recent results on X(3872) Summary. Jolanta Brodzicka (KEK) 20/11/2007 KEK. Recent KEK press release. - PowerPoint PPT Presentation
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Z(4430) and related results Z(4430) and related results at Belleat Belle
Jolanta Brodzicka Jolanta Brodzicka (KEK)(KEK) 20/11/2007 KEK20/11/2007 KEK
Outline Observation of Z+(4430)→ψ’π+ in B→ψ’π+K decays Z(4430) interpretation within 4-quark model Recent results on X(3872) Summary
Recent KEK press releaseRecent KEK press release
Jolanta Brodzicka Z(4430) and related KEK 20/11/2007 2
KEK B FactoryKEK B Factory
Jolanta Brodzicka for Belle New charmed particles JPS/DPF 2006 3 Jolanta Brodzicka for Belle New charmed particles JPS/DPF 2006 3
Asymmetric e+e- collider
e+: 3.5 GeV e-: 8.0 GeV
CM energy: 10.58 GeV at (4S)
e+e- (4S) BB Advantages:
exclusive source of BB pairs useful kinematical constraints high signal-to-background ratio separation of B decay vertices
Record luminosity peak:1.711034cm-2s-1
Integrated luminosity: ~742 fb-1
~ 780 * 106 BB
Beauty Factory
Tsukuba
Belle DetectorBelle Detector
Jolanta Brodzicka for Belle New charmed particles JPS/DPF 2006 4 Jolanta Brodzicka for Belle New charmed particles JPS/DPF 2006 4
Particle identificationParticle identificationK/ separation Central Drift Chamber: dE/dx Aerogel Cherenkov Counter Time of Flight Counter Electron identification Electromagnetic Calorimeter
KL and identification KL and muon detector
VertexingVertexing Silicon Vertex Detector
Event reconstructionEvent reconstruction Charged tracks Central Drift Chamber Silicon Vertex DetectorElectrons and photons Electromagnetic Calorimeter
Silicon Vertex Detector KL / Detector
SC Solenoid 1.5T
Central Drift Chamber
Aerogel Cherenkov Counter
Electromagnetic Calorimeter
Time of Flight Counter
8 GeV e-
3.5 GeV e+
Following B decays used:
Advantages: b→cW→ccs is Cabbibo-favored process (not rare) background reduction is possible JPof parent B is known → JPof the child particles can be
determined from angular analysis
Charmonium(-like) factoryCharmonium(-like) factory
Jolanta Brodzicka Z(4430) and related KEK 20/11/2007 5
b c u, d c
s K(*)
u, d
B charmonium (-like)
W Good place for spectroscopy study! Cabbibo-favored
vertices
Study of BStudy of B→→ψψ’’ππ++KK B0 →ψ’π+K- and B+→ψ’π+K0
s studied using 657·106 BB data
ψ’→ e+e-, μ+μ- or J/ψπ+π- J/ψ →e+e-, μ+μ- K0s→π+π-
secondary particles combined to B→ψ’π+K candidates B signal identification takes advantage of Υ(4S)→BB kinematics:
EB=Ebeam=√s/2 in cms kinematical variables used in B factories
Mbc= √E2beam- p2
B beam-constrained mass (signal at mB~5.28GeV)
ΔE=EB- Ebeam cms energy difference (signal peaks at 0)
clear
B signal
seen
Jolanta Brodzicka Z(4430) and related KEK 20/11/2007 6
hep-ex/0708.1790
Submitted to PRL
in addition to expected B→ψ’K* components
a clear band seen at M2(ψ’π+)~20GeV2
to study ψ’π+ structure we apply K*veto (both K* regions excluded)
M(ψ’π+) fitted with Breit-Wigner + phase-space like function
prominent peak
(K* veto applied)
3-body decays
non-B
background
BB→→ψψ’’ππ++KK Dalitz plotDalitz plot
Jolanta Brodzicka Z(4430) and related KEK 20/11/2007 7
M(ψ’π+)
Nsig =121 ± 30 (6.5σ)
M= 4433 ± 4 MeV Γ= 45+18-13 MeV
M2 (
ψ’π
+)
M2(Kπ+)
K*(890)
K2*(1430)
???
Z+(4430)
Is Z(4430) signal robust?Is Z(4430) signal robust? data subsets checked, K* veto changed → consistent Z parameters interference between different (S,P,D) Kπ partial waves
→ cannot produce such narrow peak in ψ’π+ B generic MC studied → Z(4430) is not a reflection interference with 3-body → does not affect Z parameters much anything else contributed besides vetoed K*’s? no
conclusion: Z(4430) signal is robust
Jolanta Brodzicka Z(4430) and related KEK 20/11/2007 8
M(Kπ) for Z(4430) signal regionwithout K* veto
we cannot determine its JP with present statistics
First candidate for a charged charmonium-like state!
Must be exotic! It could be a tetraquark state
either diquark [cu][cd] or molecular (cd)(cu)
(Charged states naturally appear within multiquark models)
ZZ++(4430) properties (4430) properties
Jolanta Brodzicka Z(4430) and related KEK 20/11/2007 9
hep-ex/0708.1790
Submitted to PRL
M(ψ’π+)
Z+(4430)
Within 4-quark modelWithin 4-quark model (by Maiani, Polosa et al.)
Z+(4430)→Ψ’π+ can be diquark-antidiquark state [cu][cd]
charged member of JPC=1+- multiplet it can be radial excitation of lowest lying
4-quarks with JPC=1++ : X0u[cu][cu] X0
d[cd][cd]
X(3872) is candidate for such 4-quark state (but doublet needed)
Mass splitting:
M(Xu ) - M(Xd) ~2(md – mu)=8 ± 3 MeV (but mixing possible)
Production rates in charged B larger than in neutral B Jolanta Brodzicka Z(4430) and related KEK 20/11/2007 10
Maiani, Polosa et al.
PRD 71, 014028 (2005)
hep-ph/0707.3354
hep-hp/0708.3997
u cuc
Xu=d c
dcXd=
B+→K+Xu B0→K0Xd
Reminder on X(3872)Reminder on X(3872) X(3872)→J/Ψπ+π- observed B+→X(3872)K+ by Belle confirmed by BaBar, CDF, D0 PDG06: M=3871.2 ± 0.5MeV Γ<2.3MeV other decay modes: X(3872)→J/Ψγ, J/Ψω, DDπ favored spin-parity: 1++ (by the decay modes
and angular analysis by CDF/Belle)
What is X(3872)? does not match any cc state predicted by quark models DD* molecule? MX-(MD*0+ MD0)= -0.6±0.6 MeV 4-quark? Would explain small width. Charged X should exist
X(3872) properties still under investigation
(mass, width, line shape, decay modes…)
Jolanta Brodzicka Z(4430) and related KEK 20/11/2007 11
PRL 91, 262001 (2003)
M(J/Ψππ)
New X(3872)New X(3872)→J/ψπ+π- resultsresults Motivated by 4-quark model predictions B+→X(3872)K+ and B0→X(3872)K0
s X(3872)→J/ψπ+π- with 657M BB control sample: B→ψ’K ψ’→J/ψπ+ π- (to calibrate mass & resolution)
look at ΔM= M(J/ψπ+ π-) - M(J/ψ)+mJ/ψ
models predicting different properties for X(3872) from
neutral and charged B decays are disfavored
Jolanta Brodzicka Z(4430) and related KEK 20/11/2007 12
BELLE-CONF-0711
B0→XK0s
Ns=30±7 (6.5σ)
B+→XK+ Ns=125±14 (12σ)
First observation!
Surprises from X(3872)Surprises from X(3872)→→DD*D*D X(3872) is very close to D*0D0 mass threshold BaBar: B+→D*0D0K K=K+or K0 D*0 →D0π0,D0γ (with 383·106 BB) Belle: B+→ D0D0 π0K K=K+or K0 (with 447·106 BB)
mass ~4σ away from X →J/Ψπ+π- are there two states X(3872) and X(3875)?
Jolanta Brodzicka Z(4430) and related KEK 20/11/2007 13
hep-ex/0708.1565 PRL 97, 162002(2006)
Ns=33 ± 7 (4.9σ)M(X)=3875.1+0.7
-0.5 ±0.5 MeVΓ=3.0+1.9
-1.4 ± 0.9 MeV
Ns=24 ± 6 (6.4σ)M(X)=3875.4 ± 0.7+0.4
-1.7 ±0.9 MeVΓ=3.0+1.9
-1.4 ± 0.9 MeV
Still within 4-quark model?Still within 4-quark model? (by Maiani, Polosa et al.)
Model revised:
Xu state decaying to D0D0π0 / D*0D0 = X(3875)
Xd state decaying to J/Ψπ+π- = X(3872)
(why Xd lighter than Xu?) predictions on rates in B decays:
neutral Z partner should exist
M~ M(Z+(4430))+few MeV
decay modes: Ψ’π0,Ψ’η or ηc(2S)ρ0, ηc(2S)ω charged partner for X(3872)/X(3875)
M~3880MeV, decay modes: J/Ψπ+ or ηc(1S)ρ+ Jolanta Brodzicka Z(4430) and related KEK 20/11/2007 14
Maiani, Polosa et al.
hep-ph/0707.3354
hep-hp/0708.3997
u cuc
Xu=
d cdc
Xd=
SummarySummary Z+(4430)→ψ’π+ observed in B→ψ’π+K by Belle First candidate for charged charmonium-like state.
It is exotic! Tetraquark interpretation favored
X(3872) →J/ψπ+π- ,DD* in B decays studied Recent results disfavor models that predict different
properties between B+→XK+ and B0→XK0
Jolanta Brodzicka Z(4430) and related KEK 20/11/2007 15
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