DsJ s

1
DsJ s charmed strange baryons at Belle
Henryk Palka INP PAS Krakow (for Belle)
2
cs spectroscopy pre-2003 era
_
Ds1(2536) 1 (?) (Argus 89) Ds2(2573) 2 (?)
(Cleo 94) ( 0- Ds , 1- Ds )
HQS-motivated potential model (Godfrey,Isgur 85)
all L1 states above DK thr., G(jq1/2) gtgt G(3/2)
G-I predicted Ds2(2573) jq 3/2, Ds1(2536) fits
nicely too (post-diction)

• 2 missing states not seen for a decade
• too wide, difficult to discover

Theory disputed m(jq1/2) gt m(3/2) (inversion),
mixing level between 3P1 and 1P1 ( HQS breaking)
3
Surprises of 2003
Babar DsJ.(2317) ? Dsp0 PRL 90, 242001 (2003)
Cleo confirmed DsJ(2317) and found another one
DsJ(2460) PRD 68, 032002 (2003)
Belle confirmations new modes PRL 92, 012002
(2004)
DsJ(2460) ? Ds ?
DsJ(2317) ? Dsp0
DsJ(2460) ? Dsp0
4
Masses and widths
Widths consistent with mass resolutions
New mass measurements from Babar m(DsJ(2317) )
2 MeV (hep-ex/0605036, 211fb-1)
m(2460) - m(2317) m(1-) - m(0-) 143 MeV
PDG04 average mass differences m(DsJ(2317))
m(Ds) 349.2-0.7 MeV m(DsJ(2460)) m(Ds)
347.1-2.2 MeV
m(2460) - m(1-) m(2317)-m(0-) 348 MeV
5
New DSJ s are produced in B decays
while BF(DDs) or DDs 10-2
6
DSJ s spin-parity from B?DDsJ
The initial state state JP0- restricts v.much
possible final state spin-parities
Angular distributions DsJ helicity frame, Ds as
a spin analyzer
DsJ(2317) ? Dsp0
DsJ(2460) ? Dsp0
J 1 ?2/d.o.f 4/8 J 2 ?2/d.o.f 89/8
J 0 ?2/d.o.f 3/8 J 1 ?2/d.o.f 38/8
JP 0
JP 1
PRL 91, 262002 (2003)
7
DSJ s decay modes summary
The only known BRs
Ds ?/ Dsp0 0.31-0.06
( PDG04 )
Dsp p-/Dsp0 0.14-0.04
BFs of the DsJ(2460)
(Babar hep-ex/0605036)
sum of all seen BF is
7620
All observed decay modes are isospin violating
8
Observation of DS1(2536) ? D p- K
hep-ex/0507030
80286 ev
xP gt 0.8
The 2nd 3-body decay of Ds1 observed ( Ds p p-
PRL 92, 012002 (2004))
2-body invariant mass spectra
m(D0) lt m(D) m(p-), also not enough energy to
produce K, D
spectra in reasonable agreement with 2 out of
3-body phase space
9
Angular studies of DS1(2536) ? DK0s
hep-ex/0507030
347464 ev
A clean signal thanks to hard charm f.f.
xP gt 0.8
the decay described by 3 angles
cos a, ß not flat? Ds1 part. polarized
cos ? D polarized
1 ? 1- 0 1Acos2? L2 A3, L0 A0
S D2 f(R,f)
A -0.70 0.03, ?2/dof 1.39
flt 42o
RGS/(GSGD)
f relative phase
10
Summary on DsJ s

• DsJ(2317) , DsJ(2460) even better known
• than Ds1, Ds2
• More precise BF measurements could
• discriminate between available models
• 4 states with right quantum numbers to
• form L1 cs multiplet, do they form it?
• Re-examination of the pot. model
• (Cahn,Jackson) pot.model rather
• inconclusive on which jq multiplet is
• heavier
• 3P1 1P1 mixing needs further studies
• (also on the DsJ(2460) side)
• Ds1?DK0s shows large S/D
• Other pot.model predictions (radial excit.,
• higher spins) should be tested
• Chiral doublers(Nowak,Zached Bardeen)
• is m(0)-m(0-)m(1)-m(1-) accidental
• (predictions for higer spin exist)

Babar J3 ? (Charm06, Meson06- talk by
Pelizaus)
11
Charmed strange baryons
Precision measurement of ?c0 and ?c masses
PLB 605, 237 (2005)
?c0 s reconstructed in 7 decay modes
12
Charmed strange baryons
?c0 and ?c masses
13
Charmed strange baryons
Study of excited states ?c(2645)
?C(2645)
?C(2645)0
Reflection from ?C(2790)0? ?c ?-, ?c ? ?c
? (verified with MC)
Reflection from ?C(2790)? ?c0 ? (verified with
MC) ?c0 ? ?c0 ?
Mass(?c ?-)
?C ? ?- ??
?C0 ? ?- ?
Mass(?C0 ?)
PDG05
14
Charmed strange baryons
hep-ex/0606051
New charmed baryons
?cx(3077)
?cx(2980)
wrong-sign ?c K ?-
?c K0s ?-
15
Charmed strange baryons
hep-ex/0606051
Search for ?cc (3520)? ?c K- ? (Selex))
p(?c)gt2.5 GeV , 835 360 ?c events
reconstructed
N8.3 37.3 lt 69.1 _at_ 90 CL
?(?cc(3520))?Br(?cc(3520)??cK-? ) / ?(?c ) lt
1.5 10-4 _at_ 90 CL
p(?c)gt2.5 GeV
16
Summary on charmed strange baryons

• ?c0 , ?c and ?c(2645) mass measurements with
• a good precision

• Three new charmed stranged barons observed

?cx(3077) ? ?c K- ? ?cx(2980) ? ?c K- ?
?cx(3077)0 ? ?c KS0 ?-

• No evidence for ?cc (3520)? ?c K- ?