Transcript Document 7674163

Properties of the DsJ states
A.Drutskoy, University of Cincinnati
First Meeting of the APS Topical Group on Hadronic Physics
October 24-26, 2004, Fermilab, Batavia
A. Drutskoy
APS Topical Group Meeting on Hadronic Physics
October 24-26, 2004, Fermilab
Outlook
1. Production of DsJ mesons in continuum
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2. Improved measurement of B -> DsJ D(*) decays
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_
0
+
3. First study of B -> DsJ K and DsJ p + decays
4. Conclusions
Last two measurements are Belle preliminary.
A. Drutskoy
APS Topical Group Meeting on Hadronic Physics
October 24-26, 2004, Fermilab
Full statistics
at U(4S) ~253 fb-1
275 x106 BB pairs
Partial statistics
includes ~140 fb-1
or 152 x106 BB pairs
A. Drutskoy
APS Topical Group Meeting on Hadronic Physics
October 24-26, 2004, Fermilab
DsJ meson production in continuum
+ (2317) -> Ds+ po decay mode in e+e- continuum.
BaBar first observed DsJ
No evidence for DsJ(2317) -> Dsg, Ds* g and Dsgg was found. CLEO
+ (2317) signal and established DsJ
+ (2460) signal.
confirmed observed DsJ
Signal widths were consistent with detector resolution.
Belle confirmed BaBar and CLEO results. Decay modes observed are
+(2317) -> Ds+p0,
+ (2460) -> D+
DsJ
D+sJ(2460) -> Ds+ * p0 and DsJ
s g.
Belle
A. Drutskoy
Belle
APS Topical Group Meeting on Hadronic Physics
Belle
October 24-26, 2004, Fermilab
DsJ meson spectroscopy
In the heavy quark limit, the total angular momentum of the light quark Jq is a good
quantum number. This leads to spectroscopy with separated Ds meson
spin-doublets: (0-, 1-), (0+,1+), (1+,2+).
D*s
Ds
DsJ(2460)
DsJ(2317)
Measured masses of DsJ(2317) and DsJ(2460) are significantly lower than
predictions from potential models. Widths are consistent with zero in
contrast to expectations.
Large theoretical efforts to explain narrow D+ (2317) and D+ (2460)
sJ
sJ
resonances: DK threshold effect, chiral partners, four-quark states?
A. Drutskoy
APS Topical Group Meeting on Hadronic Physics
October 24-26, 2004, Fermilab
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Improved measurement of BD DsJ decays
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B -> D DsJ processes are described by conventional tree diagram.
D- and D0 decay modes are combined in figures.
275x106 BB pairs.
Masses: 2320.0±1.1±2.0 and 2459.5±0.9±2.0 MeV; Width consistent with resolution
DsJ(2317)Dsp0
DsJ(2460) Ds*p0
DsJ(2460) Dsg
A. Drutskoy
APS Topical Group Meeting on Hadronic Physics
October 24-26, 2004, Fermilab
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Observation of BD* DsJ decays
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Belle also measured B -> D* DsJ decays (BaBar recently reported these Bf).
D* -and D*0 decay modes are combined in figures.
274x106 BB pairs.
DsJ(2317)Dsp0
DsJ(2460) Ds*p0
DsJ(2460) Dsg
A. Drutskoy
APS Topical Group Meeting on Hadronic Physics
October 24-26, 2004, Fermilab
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Combined (D0 and D-) results for B -> DsJ D decays
Decay_ channel
Bf, 10- 4
0
BD
_ DsJ(2317) [Dsp ]
BD
_ DsJ(2317) [Ds*g]
0
BD
_ DsJ(2460) [Ds*p ]
BD
_ DsJ(2460) [Dsg]
BD
_ DsJ(2460) [Ds*g]
BD
_ DsJ(2460) [Dsp+p-]
0
BD
_ DsJ(2460) [Dsp ]
0
B  D*
_ DsJ(2317) [Dsp ]
0
B  D*
_ DsJ(2460) [Ds*p ]
B  D* DsJ(2460) [Dsg]
10.1  1.5  3.0
4.0-1.4+1.5 (<8.4)
14.8-2.5+2.8  4.4
6.4  0.8  1.9
2.6-1.0+1.1 (<5.7)
1.0-0.4+0.5 (<2.3)
0.2-0.5+0.7 (<1.7)
3.1-1.7+2.1 (<8.5)
28.7-6.4+7.4  8.6
12.7-2.0+2.2  3.8
Significance
9.5s
3.5s
8.6s
11s
3.0s
2.6s
-2.0s
6.9s
10s
Belle branching fractions with D* meson are about two times smaller
than those obtained by BaBar.
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Measured BF an order of magnitude smaller than in B-> DsD decays with
pseudoscalar Ds. Theory : similar rates for Ds, Ds*, DsJ(2317),DsJ(2460)?
A. Drutskoy
APS Topical Group Meeting on Hadronic Physics
October 24-26, 2004, Fermilab
_
Combined (D0 and D-) results for B -> DsJ D decays
Bf(DsJ(2460)Ds g) / Bf(DsJ(2460)  Ds* p0) = 0.43  0.08  0.04
Bf(DsJ(2460)  Ds p0 ) / Bf(DsJ(2460)  Ds* p0) < 0.10 @90%CL
Bf(DsJ(2460)  Ds p+ p- ) / Bf(DsJ(2460)  Ds* p0) < 0.13 @90%CL
Bf(DsJ(2460)  Ds* g) / Bf(DsJ(2460)  Ds g) < 0.76 @90%CL
Bf(DsJ(2317)  Ds* g) / Bf(DsJ(2317)  Dsp0) < 0.70 @90%CL
J=1
J=1
J=0
DsJ(2460)  Ds* g
DsJ(2317)  Ds p0
J=0 c2/ndf=3/8 ; J=1 c2/ndf=38/8
J=2
J=1 c2/ndf=4/8 ; J=2 c2/ndf=89/8
Data agree with Jp=0+ for DsJ(2317) and Jp=1+ for DsJ(2460)
A. Drutskoy
APS Topical Group Meeting on Hadronic Physics
October 24-26, 2004, Fermilab
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_
0
+
B -> DsJ K and B0-> D-sJ p+ decays
DsJ(2317) and DsJ(2460) mesons are selected to search for B->DsJ K and B>DsJp decays.
W exchange diagram
Final state interactions
Tree, 4-quark DsJ content
+ K– final state has a completely different quark content than original B meson.
The DsJ
Within factorization approach, Cabbibo-Kobayashi-Maskawa
matrix element Vub can be obtained from ratio:
Bf(B-> Dsp+) / Bf(B-> Ds D+) = (0.424+0.041) x |Vub/Vcb|2
Measured
branching fractions (Belle):
_
+
0
-5
Bf(B
_ -> Ds K-)= (2.93+0.55+0.79)x10
Bf(B0-> Ds- p+)=(1.94+0.47+0.52)x10-5
Studies of B->DsJD, B->DsJK and B-> DsJp decays are important to
understand the nature of DsJ mesons (2- quark or 4- quark DsJ content ?).
A. Drutskoy
APS Topical Group Meeting on Hadronic Physics
October 24-26, 2004, Fermilab
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+ K- and B0-> D- p+ decays
First study of B0->DsJ
sJ
152 x106 BB pairs, L= 140fb-1
DsJ(2317)+ -> Ds+ p0 ,
D+s-> fp+, K*0K+,
KSK+
DsJ(2317) K-
6.8 s
DsJ(2317) K-
p+
DsJ(2317) p+
DsJ(2460) K-
DsJ(2460) K-
DsJ(2460) p+
DsJ(2460) p+
DsJ(2317)
A. Drutskoy
DsJ(2460)+ -> D+s g
APS Topical Group Meeting on Hadronic Physics
October 24-26, 2004, Fermilab
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+ K- and D - p+ decays
Study of B0->DsJ
sJ
Fit to mass difference DM = M(DsJ)-M(Ds)
(mass and width are allowed to float):
Data: DM(DsJ(2317))=(351.2 ± 1.6) MeV/c2
MC: DM(DsJ(2317))=(348.5 ± 0.3) MeV/c2 (2317.5)
Flat -> Jp=0+
Resolution s:
Data: s=(6.0 ± 1.2)MeV/c2 MC: s=(6.1 ± 0.2)MeV/c2
Obtained branching fraction and upper limits:
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Bf(B0->DsJ(2317)+ K-) x Bf(DsJ(2317)+->Ds+ p0) = (5.3+1.5
± 0.7 ± 1.4)x10-5
-1.3
DsJ(2317)- p+
(DsJ(2317)->Dsp0)
DsJ(2460)+ K(DsJ(2460)->Dsg)
DsJ(2460)- p+
(DsJ(2460)->Dsg)
<2.5x10-5 (90%CL)
<0.94x10-5 (90%CL)
<0.40x10-5 (90%CL)
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Measured
B0-> DsJ(2317)+ K- branching fraction is of the same order as
_
+
B0->D
_ s K branching fraction and at least 2 times larger than that
for B0->DsJ(2460)+K- decay (Bf(DsJ(2460)->Dsg)~30%) -> unexpected !!!
A. Drutskoy
APS Topical Group Meeting on Hadronic Physics
October 24-26, 2004, Fermilab
Why is that?
Bf(B0->DsJ(2317)+ D-) x Bf(DsJ(2317)+->Ds+ p0) = (10.3+2.3
± 3.1)x10-4
-2.0
Bf(B0->Ds+ D-) = (8.0 ± 3.0)x10-3
_
-5
Bf(B0->DsJ(2317)+ K-) x Bf(DsJ(2317)+->Ds+ p0) = (5.3+1.5
-1.3 ± 0.7 ± 1.4)x10
_
Bf(B0->Ds+ K-) = (2.93± 0.55 ± 0.79)x10-5
Theoretical expectations (naïve):
Bf(B0->Ds+ M)
Bf(B0->DsJ(2317)+
M)
=
~ 1, if DsJ is two-quark state.
for M = D, K, p
~ 10, if DsJ is four-quark state.
Four-quark tree diagram (for DsJ+ K- decay) can change this ratio.
Probably too naïve… Ask theorists to explain this.
A. Drutskoy
APS Topical Group Meeting on Hadronic Physics
October 24-26, 2004, Fermilab
Conclusions
n
_
Decays B -> DsJ D(*) were measured with improved accuracy.
Obtained branching fractions are of order of magnitude smaller
than those with a pseudoscalar Ds . Angular distributions
indicate that the DsJ(2317) is 0+ and the DsJ(2460) is 1+.
_
_
n
+ K- and D p+ were studied for the first time.
B0 -> DsJ
sJ
_
The branching _fraction for B0-> DsJ(2317)+ K- is of the
same order as B0->D+s K- branching fraction
_ and
more than two times larger than that for B0->DsJ(2460)+Kdecay (assuming Bf(DsJ(2460)->Dsg)~30%).
n
More experimental measurements are required to
understand the nature of DsJ mesons.
A. Drutskoy
APS Topical Group Meeting on Hadronic Physics
October 24-26, 2004, Fermilab
Background slides
Procedures to extract B signal yield
Two almost independent variables MB and
DE can be used to select B meson signal:
MB =
* )2 – (S Pi)2
(Ebeam
DE = SEi - Ebeam
*
Methods to extract B signal yield:
1) Cut on MB and fit to DE
2) Cut on DE and fit to MB
3) Double dimensional fit to
MB and DE distribution
4) If B->P1P2P3: cut DE and MB box
and look at resonant structures
in M(P1P2) mass distribution.
A. Drutskoy
APS Topical Group Meeting on Hadronic Physics
October 24-26, 2004, Fermilab
Continuum Suppression
To separate spherical BB events
from jet-like continuum
events, topological variables
are used:
1) Second Fox-Wolfram moment
2) Super Fox-Wolfram
(six modified Fox-Wolfram
moments, Fisher discriminant)
3) Angle between B meson and
beam axis direction
4) Angle between thrusts of
selected B meson particles and
all other particles in event
Likelihood ratio includes all info.
A. Drutskoy
APS Topical Group Meeting on Hadronic Physics
October 24-26, 2004, Fermilab