Open Charm Spectroscopy
Klaus Peters
GSI/GU Frankfurt
Nov 19, 2009
Mainz
Charm Production at B-Factories
D-Meson Spectrum
Ds-Meson Spectrum
Spectroscopy in D(S) decays
Outlook
Motivation
Until 2003: D/Ds spectra was not very exciting
(Godfrey,Isgur)
Prediction
Godfrey,Isgur/
DiPierro, Eichten
D
2
Measurement
Klaus Peters – Open Charm Spectroscopy
Motivation
After 2003: Further states, partly very narrow (Ds system)
inconsistent with theoretical expectations  Ds0*(2317), Ds1(2460)
(Godfrey,Isgur)
(nat. JP)
Prediction
Godfrey,Isgur/
DiPierro, Eichten
D
Evidence for 2 new states
3
Measurement
4 new states
Klaus Peters – Open Charm Spectroscopy
Motivation
Nature of the recently found states?
- cu/cd, cs states (+c.c.)
- tetraquark states (e.g. csdd)
- molecular states (near threshold, e.g. cd-ds)
Experimental observables
- masses
- lifetime/width/partial decay widths
- spin-parity
- isospin (via decay)
- mixing angles (singlett, triplett)
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Klaus Peters – Open Charm Spectroscopy
Charm Production at B-Factories
d
Resonant
W+
e+e-  γ*  bb
favored decay: b  c W-
B0, B+, Bs
c
b
c
qq
q
non-resonant qq production: e+e-  γ*  qq
cc-events rich source for D and Ds mesons
5
e+e-
σ [nb]
bb
1,05
cc
1,30
ss
0,35
dd
0,35
uu
1,39
Klaus Peters – Open Charm Spectroscopy
Heavy-Light Systems
Heavy qq
S=s1+s2
J=L+S
M
ordered by L
approximate L degeneracy
m(ηc)≈m(J/ψ)
m(χc0…2)≈m(hc1)
JP=0- JP=1- JP=0+ JP=1+ JP=2+
χf0c0
ηηc
ω
J/ψ
χf2c2
χf1c1
Light qq spectra as well
hhc1
1
same structure
not to scale
L=0
M
j=L+sL
J=j+sH
Ds
6
D s*
In Heavy-Light systems
L=1
DsJ*
*
Ds1 DsJ
}
DsJ
}
like H-atom
ordered by property
of the light quark
j=3/2
approximate j degeneracy
But the large gap between
j=1/2 j=1/2,L=1 and j=3/2,L=1
was unexpected
K. Peters - Charm Spectroscopy
D-Meson Spectrum
S-wave states (L=0)
D 0/ D ±
Mark I, 1975
D*0/D*±
Mark I, 1975
1/2 1/2 1/2 1/2 3/2 3/2
jq
mass
P-wave state candidates (L=1)
D0*(2400) Belle, 2004
D1(2420)
Argus, 1986
D1‘(2430)
Belle, 2004
D2*(2460) E691, 1989
Neutral and
charged states
L=0
L=1
Experiment
Theory
Godfrey,Isgur , Phys. Rev. D32, 189 (1985)
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Klaus Peters – Open Charm Spectroscopy
D-Meson Spectrum
Mass /
predicted
broad
narrow
Decay S-wave,
~ q2L+1  q
Decay D-wave
~ q2L+1  q5
q breakup
momentum
holds also
for Ds
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Klaus Peters – Open Charm Spectroscopy
D0, D± - Production
D0, 2006
First seen in continuum events
232 fb-1
Phys. Rev. D74
091102 (2006)
D0
D0
Mark I, 1975
D±
shows the extreme qualitiy of data, which
every new generation has to compete with
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Klaus Peters – Open Charm Spectroscopy
D2*(2460) - Production
First observed in γN  (D)X
In continuum
e+e-  (D)X
Argus
E691, 1989
In B decays
B  (D*)
B  (D)
62 fb-1
Phys. Rev. D69
112002 (2004)
progress is not as gigantic
as with light D mesons  reason: very complicated final state
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Klaus Peters – Open Charm Spectroscopy
D1(2420) – Production and Decays
B-Decays
B  (D*), B  (D)
First observed in continuum
e+e-  (D*)X and D*  D
b)
Argus, 1986
a)
Argus, 1989
Angular analysis
consistent with spin 1
Phys. Lett. B232, 398
(1989)
11
a) 62 fb-1
Phys. Rev. D69
112002 (2004)
b) 145 fb-1
Phys. Rev. Lett. 94
221805 (2005)
Klaus Peters – Open Charm Spectroscopy
D0*(2400) – Production, Parameters
First observed in
B  (D)
62 fb-1
Phys. Rev. D69
112002 (2004)
Use decay pattern for indirect
JP measurement
Allowed decay modes for
JP = 0+ D
1+ D*
2+ (D, D*)
Focus (seen in γA)
m = 2407 ± 21 ± 35 MeV/c2
 = 240 ± 55 ± 59 MeV
m = 2308 ± 17 ± 22 MeV/c2
 = 276 ± 21 ± 63 MeV
Only decay mode D
JP = 0+ favored
 11P0
12
100 MeV difference
m = 2403 ± 14 ± 35 MeV/c2
 = 283 ± 24 ± 34 MeV
Phys. Lett. B586, 11 (2004)
Klaus Peters – Open Charm Spectroscopy
D1(2430) – Production, Parameters…
First seen in B decays
62 fb-1
Phys. Rev. D69
112002 (2004)
B ±  (D*)
Color favored
B0  (D*+-)ω
Color suppressed
221 fb-1
Phys. Rev. D74
012001 (2006)
No evidence for the narrow resonances
at 2420 and 2460 MeV/c2 ?
D1(2430)
M = 2477 ± 28 MeV/c2
 = 266 ± 97 MeV
M = 2427 ± 36 MeV/c2
 = 384 ± 117 MeV
13
Only decay mode D*
JP = 1+ favored
Klaus Peters – Open Charm Spectroscopy
Ds-Meson Spectrum
cs + c.c.
States known until 2003
(CLEO, 1983)
1/2
3/2
1/2
1/2
1/2
js
3/2
(PEP4, 1984)
(Argus, 1989)
(Cleo, 1994)
L=0
14
L=1
Klaus Peters – Open Charm Spectroscopy
Ds-Meson Spectrum
cs + c.c.
States known until 2003
(CLEO, 1983)
natural spin parity
1/2
3/2
1/2
1/2
1/2
js
3/2
(PEP4, 1984)
(Argus, 1989)
(Cleo, 1994)
Discovered after 2003
(BaBar, 2003)
(Cleo, 2003)
(BaBar, 2006)
(BaBar/Belle 2006)
L=0
15
L=1
Klaus Peters – Open Charm Spectroscopy
Ds0*(2317)+ - Production
cc continuum events
first observation of this state
by BaBar in e+e-  Ds+0 +X
1)
B  Ds0*(2317)K
2)
232 fb-1
Phys. Rev. D74
032007 (2006)
16
B decays
first seen in B-decays by Belle
B  Ds0*(2317)D, Ds0*  Ds0
3)
368 fb-1
hep-ex/
0507064
Bckgr. 1) Ds*  Ds0
2) Ds*( Ds)+wrong 
3) Ds1(2460) ( Ds0)-missing 
Klaus Peters – Open Charm Spectroscopy
Ds0*(2317)+ – Parameters and Decays
Mass m = 2317.8 ± 0.6 MeV/c2
Decay width  < 3.8 MeV
(PDG 08)
Very narrow
Observations
- Mass too low compared with old potential models
(Godfrey, Dipierro)
New models work better
- Mass lies below DK threshold
 only isospin-violating and
electromagnetic decays possible
 Explanation of small width
17
Klaus Peters – Open Charm Spectroscopy
Ds0*(2317)+ – Parameters
Decay pattern
Angular distribution
B  DDs0*, Ds0* Ds
Ds0¤(2317)+ 
, 0
Ds0 (B-CMS)
B
261 fb-1
Belle Conf 0461 (2004)
qH
Ds (Ds0-CMS)
J=1
J=0
 Spin-Parity JP = 0+
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Klaus Peters – Open Charm Spectroscopy
Ds0*(2317)+ – Nature of State
Molecular state?
Ds0*(2317)0  Ds+-
Search for Ds0*(2317)0 and
Ds0*(2317)++ companions
no signal in Ds+- and Ds++
Ds0*(2317)++  Ds++
Isospin = 0
compatible with cs state
2.317
232 fb-1
Phys. Rev. D74 032007 (2006)
19
Klaus Peters – Open Charm Spectroscopy
Ds0*(2317)+ – Nature of State
Lots of tools
Production in B-decays (HQET)
Radiative production (Ds-cascade)
Radiative decays
Hadronic decays
Everything we know points to a cs state,
which is lowered in mass due to chiral corrections
But more exciting interpretations are still not excluded
need a flavor factory for more precise BR
Need a pp facility to measure or get better limits on the with
All this also holds for the next object in this talk
20
Klaus Peters – Open Charm Spectroscopy
Ds1(2460)+ - Production
cc continuum events
first observation of this state
by CLEO in e+e-  Ds*0 +X
B decays
first seen in B decays
by Belle in B  Ds1(2460)D
B  Ds1(2460)K
232 fb-1
Phys. Rev. D74
032007 (2006)
21
368 fb-1
hep-ex/0507064
Klaus Peters – Open Charm Spectroscopy
BUT – already in April 2003
BABAR
22
Klaus Peters – Open Charm Spectroscopy
Ds1(2460)+ – Parameters and Decays
Mass m = 2459.6 ± 0.6 MeV/c2
Decay width  < 3.5 MeV
Observations
-Mass too low compared with old
potential models (Godfrey, Dipierro)
New models work better
- Mass lies below D*K threshold
(PDG 08)
Klaus Peters – Open Charm Spectroscopy
23
Missing modes:
more statistic needed
Klaus Peters – Open Charm Spectroscopy
Ds1(2460)+ – Parameters
Angular distribution
B  DDs1 Ds1  Ds
Continuum, Ds1  Ds*0
J=1
JP = 0-
J=2
261 fb-1
Belle Conf 0461
(2004)
24
JP = 1+, 2-, 3+, …
 J=1
 Spin-Parity JP = 1+
232 fb-1
Phys. Rev. D74
032007 (2006)
Klaus Peters – Open Charm Spectroscopy
Ds1(2460)+ – Nature of State
Relative Branching fractions
Different branching fractions  not from same spin doublet
Mixing angle
There are two 1+ states, (Ds1(2460)+ , Ds1(2536)+)
mass difference m ~ 76 MeV
 investigation of mixing with Ds1(2536)+
seem to be small !
25
Klaus Peters – Open Charm Spectroscopy
Ds1(2536)+ - Production
cc continuum events
first seen in e+e-  D*K, D*  D
B decays
first seen in B decays
by BaBar B  D(*)D(*)K
ARGUS 1989
D K, K
D  K0
347 fb-1
Phys. Rev. D 77
011102 (2008)
Large signals observed
 very precise Measurements
of mass and width possible
26
Klaus Peters – Open Charm Spectroscopy
Ds1(2536)+ - Parameters
continuum events e+e-  (D*+K)X, D*+  D0+
Large signals  Precise measurement of mass, width
PDG: 525.3 ± 0.6 ± 0.1 MeV/c2
First measurement of Ds1(2536) decay width:
232 fb-1
hep-ex/0607084 (preliminary)
27
Klaus Peters – Open Charm Spectroscopy
Ds2*(2573)+ – Production and Decays
First seen in cc continuum
CLEO
1994
100 events
No angular distribution measured
Decay mode consistent with 2+ 13P
2
Inclusive study of e+e-  (DK)X
Large signal: Improvement in precision
for Ds2(2573)
Phys. Rev. Lett. 97
222001 (2006)
240 fb-1
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Klaus Peters – Open Charm Spectroscopy
DsJ*(2700)+ - Production
Seen by Babar in cc continuum
Inclusive study of e+e-  (DK)X
Phys. Rev. Lett. 97
222001 (2006)
240 fb-1
29
Seen by Belle in
B+ → D0DsJ(2700)+, DsJ(2700)+→D0K+
Same state?
Phys. Rev. Lett. 100
092001(2008)
414 fb-1
Klaus Peters – Open Charm Spectroscopy
DsJ*(2700)+ – Parameters
final state  natural spin-parity
preferred angular distribution
Phys. Rev. Lett. 100
092001(2008)
414 fb-1
-
JP=1
Possible interpretations
- Radially excited 23S1 (excited Ds*)
predicted mass ~2720 MeV/c2 [ref 1]
- Chiral doublet 1- state to 1+ Ds1(2536)+
predicted (2721 ± 10) MeV/c2 [ref 2]
J=1
J=0
J=2
1) Godfrey, Isgur PRD 32, 189 (1985)
Close et al., PLB 647, 159 (2007)
2) Nowak et al.,
Acta Phys. Pol. B 35, 2377 (2004)
Confirmation needed !!
Important !!
D*K and Ds(*)η
30
Klaus Peters – Open Charm Spectroscopy
DsJ*(2860)+ - Production, Parameters …
First observed in e+e-  (DK)X
DsJ*(2860)
Phys. Rev. Lett. 97
222001 (2006)
240 fb-1
Phys. Rev. Lett. 100
092001(2008)
414 fb-1
final state  natural spin-parity
31
DsJ*(2860) not seen in B decays.
high spin for this meson ?
high spin supports small width
D*K and Ds(*)η important
Klaus Peters – Open Charm Spectroscopy
Dalitzplot Analysis for D-Decays
Lorentz invariant, and phase space flat.
– Allows resonance parameters and spin to be well measured.
– Starts from a well-defined spin 0 particle
– Expect intermediate resonances to have J≤2
(because of limited two-body-mass range,
and centrifugal barrier suppression)
– however, parity and isotopic spin are not conserved in the decay
•Charm Dalitz plots have many uses:
–
–
–
–
32
New measurements in light meson spectroscopy
Key role in CKM-measurement
Fundamental information needed to understand heavy mesons decay
Mixing and CP violation studies
Klaus Peters – Open Charm Spectroscopy
D0 K0π+πRelevant for measurement
of γ in BDK
Belle BW, 2σ resonances
but χ2=2.72
arXiv:0803.3375, Phys.Rev.D73:112009,2006
Babar K-Matrix, χ2=1.11
487,000 events
Phys.Rev.D78:034023,2008
33
Klaus Peters – Open Charm Spectroscopy
Model independent D+K-π+π+
E791
Phys.Rev.D73:032004,2006
Kπ P-wave
 K ∗(892),K∗1(1410),K∗1(1680)
Breit-Wigners.
Kπ D-wave
 K∗2 (1430) Breit-Wigner.
Kπ S-wave
extracted by splineinterpolation over 40 points.
At each point amplitude and
phase are free parameters.
c0(sk)eiφ0(sk)
Kπ S-wave: Broad structure
with dip at the
K∗0(1430) resonance.
34
Klaus Peters – Open Charm Spectroscopy
some more details
LASS curve normalized to the E791 data at 1.3 GeV.
Phase normalized to the same mass shifting down by 700.
Watson theorem requires elastic phase to be the same
35
Klaus Peters – Open Charm Spectroscopy
Model independent D+π-π+π+
Phys. Rev. D 79, 032003 (2009)
36
Klaus Peters – Open Charm Spectroscopy
Scalar studies in semileptonic D(s) decays
Scalar waves are always problematic and
unambiguous coupled channels are hard to identify
(overlaps, crossings etc.)
New concept: Semileptonics Ds-decays
Example: e+e-  ψ(4040)  Ds+Dsand Ds+
 ππl+ν (π+π-, π0π0)
 η(‘)η(‘)l+ν
 KKl+ν (KSKS, K+K-) and l=e,μ
W
M
Model independent analysis possible
Use K-Matrix to analyze data
Coupled channel fit simple
37
M
or lν
M
M
W
M
M
GSI - Group Report for BESIII@BEPCII
Outlook
for the D(S)-Spectrum
 Necessary ingredients to differentiate among models
accurate total width measurements / partial decay widths
hadronic and radiative transitions to Ds0*(2317)/Ds1(2460)
from higher mass states
test of mixing schemes
 Tools
ongoing BaBar / Belle / Cleo / CDF / D0 analyses
high luminosity B-factories
LHCb (Bs decays)
charm production with pp @ PANDA @ FAIR
(see T. Stockmanns)
for the hadronic (light) D(s)-Decays
ongoing BaBar / Belle analyses
may be soon be superseded by BES3
38
Klaus Peters – Open Charm Spectroscopy