Βdecays to open charm and charmonium from babar’decays to open charm and charmonium from babar...
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Β decays to open charm and charmoniumfrom BaBarStefania RicciardiRoyal Holloway, University of LondonOn behalf of the BaBar Collaboration
32nd International Conference on High Energy Physics Beijing, August 16-22nd,2004
ICHEP04Stefania Ricciardi, BaBar2
OutlineTesting models of hadronic Β decays
Inclusive charm production in Β decaysΒ0 → Ds*+ D*− [and Ds → φ π+]Β0 → D(*)−ppπ+, Β0 → D(*) 0ppExclusive Β → (cc) K(*), where cc = J/ψ,ψ(2S),χc
Charm and Charmonium Spectroscopy: Β decays to DsJ (2317) and DsJ (2460)X(3872)
For new results on Β→ D(*)K(*) and Β→ Ds+ρ −
see L.Cavoto’s talk in the CP violation session
All results are PRELIMINARY
ICHEP04Stefania Ricciardi, BaBar3
Inclusive charmHadronization models (Heavy Quark Expansion)predict average charm multiplicity in B decays, nc ≈ 1.2-1.3
[Bagan et al. PLB351(1995)Buchalla and Dunietz, PLB364(1995)Neubert and Sachrajda, Nucl.Phys.B483(1997)]
We define:• Flavor correlated charmcorrelated charm
production from dominant b→c transition
• Flavor antianti--correlated charmcorrelated charmproduction from W− → cs’ decay
b cu u
W −
B−
s’c
) ( Nc
c XXB cX
→−∑= B
[charge-conjugationimplied everywhere]
)(,,,, ,0 ccDDDX ccc S ΞΛ= +++
) ( Nc
c XXB cX
→−∑= B
ccc N N n +=)(,,,, 0 ccDDDX cc S−−− Λ=
ICHEP04Stefania Ricciardi, BaBar4
Inclusive charm: a new experimental method
Full reconstruction of one B = BrecoCharm hadron searched for in rest of event, fully reconstructed and correlated with charge of parent B = Brecoil
We correct for: mixing in the B0 sample and background from B0 (B+) in the B+ (B0) sample
**
**
BrecoBrecoil
BrecoBrecoil
recorecoil
pp
EE
BB
−=
=
=Y(4S)→ Β Β :
e− e+
Y(4S)B+
B−
Kπ
D0
X
D+, D0, Ds,Λc
π, ρ,a1
Brecoil
Breco
(#)
(# at the time of Brecodecay only, for neutral B)
→ →
ICHEP04Stefania Ricciardi, BaBar5
Inclusivecharm
Data sample: 89 million B pairs
D0
D+
D+S
D0
D−
D−S
Λ−c
B−
corr
elat
ed
B−
anti-
corr
elat
ed
BaBar Preliminary
Λ+c Signal
41±9Signal33±9
Signal11±5
Signal82±11
Signal262±29
Signal98±20
Signal1273±42
Signal160±16
Blue-shaded areas: true charm particlesfrom background of misreconstructed B
• Significant production ofcorrelated D0 and D+
• Ds correlated production small. Anti-correlated dominant.
ICHEP04Stefania Ricciardi, BaBar6
Inclusive charm: branching fraction
correlated anti-correlated
Xc B(B−→ XcX) % B(B−→ XcX) %
D0 51.1 ± 3.1 ± 2.5+1.3-1.3 6.3 ± 1.9 ± 0.5+0.2
-0.2
D+ 39.7 ± 3.0 ± 2.8+2.8-2.5 2.3 ± 1.8 ± 0.3+0.2
-0.2
< 5.1 at 90% CL
D+s 3.9 ± 1.7 ± 0.4+1.3
-0.8
< 8.7 at 90% CL10.9 ± 2.1 ± 0.8+3.8
-2.3
Λ+c 4.9 ± 1.7 ± 0.4+1.8
-1.0 2.0 ± 1.2 ± 0.2+0.7-0.4
<3.9 at 90%CL
correlated anti-correlated
Xc B(B−→ XcX) % B(B−→ XcX) %
D0 79.3 ± 2.5 ± 4.0+2.0-1.9 9.8 ± 0.9 ± 0.5+0.3
-0.3
D+ 9.8 ± 1.2 ± 1.2+0.8-0.7 3.8 ± 0.9 ± 0.4+0.3
-0.3
D+s 0.5 ± 0.6 ± 0.2+0.2
-0.1
<2.2 at 90% CL14.3 ± 1.6 ± 1.5+4.9
-3.0
Λ+c 3.5 ± 0.8 ± 0.3+1.3
-0.8 2.9 ± 0.8 ± 0.3+1.1-0.6
B− recoil
N(B+RECO) = 85840 ± 1910
B0 recoil
N(B0RECO) = 48322 ± 590
• First measurement ofD+
s correlated• Sizeable Λc
production
ICHEP04Stefania Ricciardi, BaBar7
Inclusive charm: nc0
, nc−
We find no evidence ofB− →Λc
+ Λc− K
looking at the missing mass distribution (obtained from the B 4-momentum, a K and a reconstructed Λc or Λc)
We estimate B(B− →Ξc X) = B(B− →Λc
− X) - B(B− →Λc+ Λc
− K) ≅ B(B− →Λc− X)
B(B− →Ξc X) neglectedUsing B(B− →(cc) X) = (2.3 ± 0.3) %,
we determine separately for the first time:
058.0 0.0621.276n 062.0 0.0371.313n
012.0 0.0360.237N 020.0 0.0220.330 N
049.0 0.0511.039N 046.0 0.0300.983 N
066.0046.0
0c
063.0042.0c
039.0024.0
0c
051.0031.0c
039.0031.0
0c
028.0023.0c
+−
+−
−
+−
+−
−
+−
+−
−
±±=±±=
±±=±±=
±±=±±=
Previous results (hep-ex/0112028)1.175 ± 0.042 (CLEO)1.230 ± 0.042 (LEP+SLD) 1.206 ± 0.033 (Average)
=cn
B− B0
ICHEP04Stefania Ricciardi, BaBar8
Β0 → Ds*+ D*−
New measurement of B(Β0 → Ds*+ D*−)Experimental test of factorization at high q2 values:q2~m2(Ds*+)
New measurement of B(Ds+→ φ π+)
used to normalize other Ds+ branching fractions
The present ~25% uncertainty
B (Ds+→φ π+ ) = (3.6 ± 0.9)% (CLEO)
propagates to all analyses where a Ds(*) is
reconstructed
ICHEP04Stefania Ricciardi, BaBar9
Β0 → Ds*+ D*−: method
With a partial reconstruction technique, determine
B1 = B (B0 → Ds*+ D*-)
Fully reconstruct final state with Ds+→ φ π+
and measure
B2 = B (B0 → Ds*+ D*-) x B (Ds
+→ φ π+)
B (Ds+→ φ π+) = B2/B1.
Many systematics cancel in the ratio.
ICHEP04Stefania Ricciardi, BaBar10
Β0 → Ds*+ D*− : partial reconstruction
hep-ex/0408040124 million B pairs
0B∗D
0D
∗SD
)( SD
−π
−+−+−+
−+−+
πππππ
πππ
SKKKK
,,, 0
γ
Ds+ from Ds
*+ → Ds+γ is not reconstructed
Pair D*- (→ D0 π-) and γ , assuming they come from B0→ Ds
*+D∗−
This BaBar Resultindependent of B(Ds
+→ φπ+) :
B(B0→ Ds*+D*-) = (1.85 ± 0.09(stat) ± 0.16(syst) )%
B(B0→ Ds*+D*-) theor= (2.4 ± 0.7)%
in agreement with previous:
and theory (Luo and Rosner,2001):
Signal: 7414 ± 345
B(B0→ Ds*+D*-) = (1.9 ± 0.5)% (PDG2004)
22 )()( ** γγ pppEEEm DBDbeammiss ++−−−= → → →
ICHEP04Stefania Ricciardi, BaBar11
Ds+→ φ π+ :ResultsD* and γ selection analogous to inclusive analysisDs+→ φ (→K+K−) π+ fully reconstructed
measure branching fraction product:
Signal 212 ±19
2*4/ BES psm −= Dividing by our measurement of B(B0→ Ds
*+D*-), we obtain
B(Ds+→ φ π+) = (3.6 ± 0.9)% (CLEO)
to be compared with
Readjustment of many results needed!Not used yet for other results in this talk
B (B0 → Ds*+ D*−) x B (Ds
+→ φ π+) = (8.71 ± 0.78(stat)) x10-4
B(Ds+→ φ π+) = (4.71 ± 0.47(stat) ±0.35(syst))%
ICHEP04Stefania Ricciardi, BaBar12
B0→D(*)−ppπ+ and B0→ D(*)0pp
Decay B (10-4) Reference B (10-4)
B0→D*−ppπ+ 5.61 ± 0.59 ± 0.73 6.5+1. 3-1.2 ± 1.0 (CLEO)
B0→D−ppπ+ 3.80 ± 0.35 ± 0.46 −
B0→D*0pp 0.67 ± 0.21 ± 0.09 1.20+0.33-0.29 ± 0.21 (Belle)
B0→D0pp 1.24 ± 0.14 ± 0.12 1.18 ± 0.15 ± 0.16 (Belle)
hep-ex/0408035124 millions B pairs
BB00→→DD**−−ppppππ++
130 ± 14BB00→→DD−−ppppππ++
238 ± 22
BB00→→DD**00pppp13 ± 4
BB00→→DD00pppp96 ± 11
• Full reconstruction• Explore dynamics of decays
involving baryons• Multi-body decays to baryons
sizeable, as found by CLEO& predicted
I.Dunitez, PRD (1998)Hou and Soni, PRL (2001)Chua, Hou and Tsai, PRD (2002)
No evidence of θ0c+ @ 3.1 GeV
BB00→→DD**−−ppppππ++
ICHEP04Stefania Ricciardi, BaBar13
Β → (cc) K(*)
Exploring heavy quark dynamics by measurements of exclusive Βdecay rates to modes allowed in the factorization scheme (charmonium JPC=1−− or 1++) [12 decay modes]:
B → J/ψ K(*)B → ψ(2S) K(*)
B → χc1 K(*)
and suppressed (⇒ measure size of non-factorizable contributions)(JPC=0++ or 2++) [8 decay modes]:
B → χc0 K(*)
B → χc2 K(*)
Measurement of CP asymmetriesin the charged modes to search for effects due to “New Physics”
[Diehl and Hiller, JHEP 0106 (2001)]
Charmoniumreconstructed in
• J/ψ(ψ(2S)) → l+l-
• χc→ J/ψγ
ICHEP04Stefania Ricciardi, BaBar14
B (Β → (cc) K(*)) Resultshep-ex/0408036124 million B pairs
Channel BR (10-4) PDG2004B+ → J/ψ K+ 10.55 ± 0.15 ± 0.48 10.0 ± 0.4B0 → J/ψ K0 8.73 ± 0.23 ± 0.30 8.5 ± 0.5
B+ → J/ψ K*+ 14.34 ± 0.36 ± 0.94 13.5 ± 1.0
B0 → J/ ψ K*0 12.92 ± 0.25 ± 0.75 13.1 ± 0.7
B+ → ψ (2S) K+ 6.31 ± 0.33 ± 0.44 6.8 ± 0.4
B0 → ψ(2S) K0 6.60 ± 0.60 ± 0.46 6.2 ± 0.7
B+ → ψ (2S) K*+ 6.03 ± 0.85 ± 0.91 9.2 ± 2.2
B0 → ψ (2S) K*0 6.65 ± 0.57 ± 1.00 8.0 ± 1.3
B+ → χc1 K+ 5.72 ± 0.24 ± 0.64 6.8 ± 1.2
B0 → χc1 K0 4.56 ± 0.39 ± 0.51 4.0 +1.2-1.0
B+ → χc1 K*+ 2.89 ± 0.69 ± 0.93 new
B0 → χc1 K*0 3.19 ± 0.37 ± 0.64 4.1 ± 1.5
0
10
20
30
5.2 5.225 5.25 5.275 5.3
mES (GeV/c2)mES (GeV/c2)mES (GeV/c2)mES (GeV/c2)
Even
ts/2
MeV
mES (GeV/c2)mES (GeV/c2)
Babar Preliminary
mES (GeV/c2)mES (GeV/c2)mES (GeV/c2)
BB00 →→ χχc1 c1 KK*0*0
BB++ →→ χχc1 c1 KK*+*+
0
20
40
60
80
5.2 5.225 5.25 5.275 5.3
mES (GeV/c2)mES (GeV/c2)mES (GeV/c2)mES (GeV/c2)Ev
ents/
2 M
eVmES (GeV/c2)mES (GeV/c2)
Babar Preliminary
mES (GeV/c2)mES (GeV/c2)mES (GeV/c2)
ICHEP04Stefania Ricciardi, BaBar15
Β → (cc) K(*): Other Results
03.002.014.1) )cc(.(.) )cc(.(.
(*)00
(*)
±±=→→ ++
KBFBKBFBCharged/Neutral Ratio
assuming equal production of charged and neutral at Y(4S) (i.e., R+/0 =1)R+/0 (assuming isospin invariance and τB+/ τB0=1.086 ± 0.017 from PDG2004)
03.002.005.1))4S(())4S((
00
0/
±±=→ΥΓ→ΥΓ
=−++
BBBBR Final state Asymmetry
J/ψ K+ -0.029 ± 0.014 ± 0.010J/ψ K*+ 0.045 ± 0.025 ± 0.011ψ(2S)K+ 0.059 ± 0.051± 0.021ψ(2S)K*+ -0.063 ± 0.137 ± 0.050
χc1 K+ 0.011 ± 0.042 ± 0.017χc1 K*+ -0.403 ± 0.309 ± 0.237
Charge CP Asymmetries
))(.(.))(.(.))(.(.))(.(.
(*)(*)
(*)(*)
−−++
−−++
→+→→−→
=KccBFBKccBFBKccBFBKccBFBACP
All measurements compatible with no direct CP asymmetry.
ICHEP04Stefania Ricciardi, BaBar16
Factorization suppressed decaysB+ → χc0 (→ ππ,KK) K+ observed by Belle and BaBar with
B.F. >10-4, i.e., comparable to factorization allowed decays
hep-ex/0408033124 million B pairs
Radiative BF relatively large for χc2:• B (χc0 → J/ψ γ) = (1.18 ± 0.14)%• B (χc1 → J/ψ γ) = (31.6 ± 3.3)%• B (χc2 → J/ψ γ) = (20.2 ± 1.7)%
χc2 BF (10-4) (90% CL)
K+ <0.36K0 <0.44K*+ <0.14K*0 <0.22
Upper limits for B → χc2 K(*)
an order of magnitude smallerthan B.F. for factorization allowed modes and B → χc0 K(*)
χc1χc1
χc2 χc2χc0
No statistical significant signal
χc0
m(llγ) – m(ll)
Spectroscopy
Β Mesons Heavenly Gateways
to Forbidden States…
ICHEP04Stefania Ricciardi, BaBar18
Study of B → DsJ(*)+D(*)
Godfrey-Isgur model
S-wave P-wave
Ds+
Ds*+
Ds1(2536)+
DsJ (2573)+
Ds0(2317)
Ds1(2460)
DsJ*(2317)+, DsJ (2460)+
Observed by BaBar, Belle and CLEO Unexpectedly below threshold for DK and D*K, respectively Consistent with P-wave csstates but other interpretations not ruled outIf cs, observed decays
• DsJ*(2317)+ → Ds
+ π0
• DsJ (2460)+ → Ds*+ π0
are isospin violating ⇒ narrow DsJ (2460)+ → Ds
+ γalso observed (and used hereto determine J)
ICHEP04Stefania Ricciardi, BaBar19
B → DsJ(*)+ D(*) hep-ex/0408041
Data sample: 122 million B pairs
DDsJsJ**(2317)(2317)++→→ DDssππ00
DDsJsJ(2460)(2460)++→→ DDss**ππ00
DDsJsJ(2460)(2460)++→→ DDssγγ
mmESES mm((DDsJsJ)
Full reconstruction of the exclusiveΒ decay
Sum over all D(*)(0) modes
Signal:88 ± 17 events
112 ± 14 events
139 ± 17events
020.0045.0274.0
))2460(.(.))2460(.(.0*
±±=
=→
→++
++
πγ
sDDFBDDFB
sJ
ssJ
We measure:
ICHEP04Stefania Ricciardi, BaBar20
B → DsJ(*)+D* Results
First measurement of all these modes
m(Ds+π0) m(Ds
*+π0) m(Dsγ )
B.F. (10-3) DsJ*(2317)+ →Dsπ0 DsJ(2460)+→Ds*π0 DsJ(2460)+→ Dsγ
B0 1.5 ± 0.4 ± 0.2(+0.5-0.3)
0.9 ± 0.6 ± 0.2(+0.3-0.2)
2.3 ± 0.3 ± 0.3(+0.8-0.5)5.5 ± 1.2 ± 1.0(+1.9-1.2)
7.6 ± 1.7 ± 1.8(+2.6-1.6)B+ 1.4 ± 0.4 ± 0.3(+0.5-0.3)
B.F. Productsfor B→DsJ
(*)+D*
ICHEP04Stefania Ricciardi, BaBar21
B → DsJ(*)+D Results
m(Ds+π0) m(Ds
*+π0) m(Dsγ )
B.F. (10-3) DsJ*(2317)+ →Dsπ0 DsJ(2460)+→Ds*π0 DsJ(2460)+→ Dsγ
B0 1.8 ± 0.4 ± 0.3(+0.6-0.4)
1.0 ± 0.3 ± 0.1(+0.4-0.2)
0.8 ± 0.2 ± 0.1(+0.3-0.2)2.8 ± 0.8 ± 0.5(+1.0-0.6)
2.7 ± 0.7 ± 0.5(+0.9-0.6)B+ 0.6 ± 0.2 ± 0.1(+0.2-0.1)
B.F. Productsfor B→DsJ
(*)+D
in good agreement with Belle results
ICHEP04Stefania Ricciardi, BaBar22
B→DsJ(2460)+D : Helicity J=2J=1
DsJ+ (2460)
Ds
γ
θh
Data points from m(Dsγ) fitscorrected for detector acceptanceand efficiency
J=1 (χ2=4.0/4) preferred to J=2 (χ2=36.4/4)
confirms Belle measurement
ICHEP04Stefania Ricciardi, BaBar23
X(3872) from B−→J/ψ K−π+π−hep-ex/0406022117 million B pairs
mX(3782)= 3873.4 ±1.4 MeV/c2
B(B-→X(3872)K-) x B(X(3872)→J/ψπ+π-) = (1.28 ± 0.41) x10-5
m(J/ψπ+π−)ψ(2S)
X(3872)
• Discovered by Belle(2003) in B decays• Confirmed by CDF,D0 and BaBaras narrow state decaying to J/ψ π+ π−
• Nature unknown (Charmonium, DD* molecule, ccg hybrid?)
• Most puzzling: mass @ D0D*0 threshold
30.5 ± 5.8 signal events ,after bkg (combinatorial and peaking) subtraction, in 20 MeV:3.862 < mX <3.882 GeV
Accumulation near kinematic limit in m(π+π−)which is ~m(ρ0) for X(3872). Isospin-breaking ? More data needed!
m(π+π−)
ψ(2S)
X(3872)
ICHEP04Stefania Ricciardi, BaBar24
Search for B→ X −(3872) KData sample:213 million B pairs
• If observed decay is X(3872)→J/ψρ0
⇒ charged partner may exist X(3872) −→ J/ψρ-
• Search for B0 → X−K+, B− → X−K0s
(and charged conjugates) with X− → J/ψ π−π0
• If X isovector, decay rate to X± should be twicethat observed for neutral X [BaBar: (1.28 ± 0.41) x10-5]
B0
m(J/ψπ−π0)
mES for |m(X)-3872| < 12MeV
Consistent with peaking background (estimated from mX sidebands)
Mode B0 → J/ψ π−π0K+ B−→ J/ψ π−π0K0s
n obs. 87 31n bkg. 101.8 ± 10.2 27.6 ± 6.2n signal -14.8 ± 13.9 3.4 ± 8.390%CL < 5.8 x 10-6 < 11 x 10-6
A likelihood ratio test excludes isovector hypothesis (Probability <1/600)
B0
X−?
ICHEP04Stefania Ricciardi, BaBar25
SummaryNew results on Β decays to open and hidden charm from BaBar:
Powerful application of recoil method for first separate determination of nc
− and nc0
Most precise measurement of Β0 → Ds*+ D*− and Ds branching fractions
Improved measurements of Β0 → D(*)-ppπ+, Β0 → D(*) 0ppImproved results of many exclusive Β decays to charmonium, including:
• measurement of B+ → χc1 K*+
• stringent upper limits on B → χc2 K(*)
First observation of B→ DsJ(*)+D*
New insights on X(3872): isovector hypothesis excluded
B(Ds+→ φ π+) = (4.71 ± 0.47(stat) ± 0.35(syst))%
Additional SlidesAdditional Slides
ICHEP04Stefania Ricciardi, BaBar27
Ds+→ φ π+
Signal 212 ±192*4/ BES psm −= B(Ds
+→ φ π+) = (3.6 ± 0.9)% PDG2004 (CLEO)
B (B0 → Ds* D*−, Ds→ φ π+) = (8.71 ± 0.78(stat)) x10-4
B(Ds+→ φ π+) = (4.71 ± 0.47(stat) ±0.35(syst))%
22 )()( ** γγ pppEEEmDBDbeammiss ++−−−=
Signal 7414 ± 345
1 - Partial reconstruction:
2 - Full reconstruction:
B(B0→ Ds*+D*-)=(1.85 ± 0.09(stat) ± 0.16(syst) )%
0B∗D
0D
∗SD
)( SD
−π
γ
Partial reconstruction resultindependent of B(Ds
+→ φπ+):→→→
−+−+−+
−+−+
πππππ
πππ
SKKKK
,,, 0Data sample
124 million B pairs
From the ratio BaBar obtains:
ICHEP04Stefania Ricciardi, BaBar28
Ξc ProductionB(B− →Ξc X) = B(B− →Λc
− X) - B(B− →Λc+ Λc
− K)CKM allowed processes
1
2
3
Anticorrelated Λc productionnot many different ways