Sep. 29, 2006 Henry Band - U. of Wisconsin 1 Hadronic Charm Decays From B Factories Henry Band...

Sep. 29, 2006 Henry Band - U. of Wisconsin 1

Hadronic Charm DecaysFrom B Factories

Henry BandUniversity of Wisconsin

11th International Conference on B Physics

at Hadron MachinesOxford, Sept. 25-29, 2006


Talk Outline

Strange charmed mesons• DsJ(2860)+

• DsJ(2700)+

• Ds2(2573)+

• Ds1(2536)+

• Ds1(2460)+

• Ds0*(2317)+

• Ds*(2112)+

Abs. Branching Fractions • Ds

+→ K+ K- + • Ds

+→ +

Branching Fractions • D+→+0 • D+→K+0 • D0→ -+0

• D0→ K-K+0

Charm Baryons c(2940)

Λc(2880)+

c*

Ξc(2980)+

Ξc(3077)+

Sep. 29, 2006 Henry Band - U. of Wisconsin

BaBar and Belle

e+e-cc • continuum 1.3 nb • Off and on peak (4S)• 30% more cc than bb

bc• Cabbibo favored

Peak luminosity 1.211034 cm–

2s–1

Integrated luminosity 390 fb–1

Peak luminosity 1.651034 cm–

2s–1

Integrated luminosity 630 fb–1

Sep.

ab-1 integrated flux combined

B FactoriesC


Ds family mesons

Observation by BaBar, Cleo, and Belle of Dsj(2317) and

Dsj(2460) at lower masses than expected by HQS theories

raised questions about cs meson spectroscopy

Ds mesons or exotics (4 quarks)?

Gather more info

• Masses

• Width

• Decay modes

• Branching fractions

• Other decay modes

• New states

DsJ*(2317)

DsJ(2460)

Ds

Ds*

Ds1(2536)

Ds2(2573)

QQ

qq


Spin Analysis

DsJ*(2317)

DsJ(2460)

Ds

Ds*

Ds1(2536)

Ds2(2573)

QQ

qq

J = 0: 2/d.o.f = 3/8J = 1: 2/d.o.f = 38/8

JP = 0+

DsJ(2317)→Dsπ0

Belle-CONF-0461 (2004)

274M BB

J = 1: 2/d.o.f = 4/8J = 2: 2/d.o.f = 89/8

JP = 1+

DsJ(2460)→Ds γ

B decays


Survey of Decays to DsFinal States

Select Ds→ K+K-+

Require K+K- or• K*(892) K-+

• p*> 2.2 GeV

Combine with , K, , 0

Tighter cuts on p* and kinematics to select intermediate states (Ds

(*), DsJ(2317))

Subtract DsX bkg using Ds mass sidebands

Fit mass spectrum • signal Breit-Wigner resolution

• Combinatorial background • include pdfs for possible reflections from othercs states

No cut

Cuts on intermediate

states

sid

eban

ds si

gnal

~4 105 Ds

+

Hep-ex 0604030


DsDs*(2112), Ds1(2460)

Ds - Combine Ds with ‘s > 150 MeV/c

Raise E > 500 MeV/c Fit signal peak + sum

o Bkgdo Ds0

*(2317) Ds+)

o Ds1(2460) Ds*(2112)+)

232 fb-1

Ds1(2460)+Ds+

Ds sidebands

N=920±60

Bkgd. subtracted

Hep-ex 0604030

Ds+

invariant mass (GeV/c2)

Ds+


D s *

(2112)+N=

75,000


Ds Ds0*(2317)

Ds+

0 invariant mass (GeV/c2)

Combine Ds with 2 ‘s

consistent with Fit Ds

+ 0 mass spectrum to Ds0

*(2317) Ds+

Ds1(2460) Ds+

Ds*(2112) Ds

+

Reflections from Ds

*(2112) Ds+(+)

Ds1(2460) Ds*(2112)+(-)

Combinatorial bkgd

232 fb-1

Ds0*(2317)+

Hep-ex 0604030

N= 26,500


Ds DsDsDs1(2460)

Ds 0 Assume Ds1(2460) Ds*(2112)+0

Require 2092< m(Ds MeV/c Fit signal + reflections

Ds 0 0 no signal Ds no signal

232 fb-1

Ds sidebands

Light shade:

Ds*(2112)

reflection

Dark shade:

DsJ*(2317)

reflection

N=560±40

Preliminary

Hep-ex 0604030

Ds 0

Ds1(2460)+

038.0036.0337.0))2460((B

))2460((B0

±±=→→

++

++

ssJ

ssJ

DDDD

Ds+

0 invariant mass (GeV/c2)


Ds±, DsDs1(2460)+ Ds1(2536)+

Look for isospin partners• Ds

+-: no signal

• Ds++: no signal

Ds +-: no DsJ

*(2317)

Strong signals Ds1(2460)+

Ds1(2536)+ Ds + -

232 fb-1

Ds1(2536)+

DsJ(2460)+

Hep-ex 0604030

Ds+ -

Ds+ +

008.0013.0077.0))2460((B

))2460((B0

±±=→→

++

−+++

ssJ

ssJ

DDDD

Ds+

+ invariant mass (GeV/c2)


D0K+, D+K0s - Ds2(2573)+, DsJ(2860)+, X(2690)+

Look for new states in continuum above DK mass

Cuts on D0(+) and Ks reconstructed masses• a) D0 K-+ (950,000)• b) D0 K-+0 (790,000)• c) D+ K-++ (430,000)

Hep-ex 607082

D+

D0

D0

232 fb-1


New States - DsJ(2860)+, X(2690)+ (?)

New resonance at 2.86 GeV/c2 Broad state at 2.69 GeV/c2

Hep-ex 0607082

Combined modes bkgd subtracted

DsJ(2860)+

Ds2(2573)+


D0 K-+ D0 K-+ 0 D+ K-++


DDsj sj Production in B decaysProduction in B decays

BELLE has observed DDsj sj

production in several modesproduction in several modes BBDDDDsjsj(2317) or DD(2317) or DDsjsj(2460)(2460)

• Established spinsEstablished spins

BBKK--DDsjsj(2317) or K(2317) or K--DDsjsj(2460)(2460) BB++→→DD00DD00KK++

• S = 399 ± 40 S/B ~ 0.3• Dalitz plot and mass projections - different from 3-body phase space


447M BB

_ _

__

_

+


BB++→→DD00DD00KK++

Contributions from several sources

Is DsJ(2700) = X(2690) ?


447M BB

■B+→D0DsJ(2700) ■B+→ψ(3770)K+ ■B+→ψ(4160)K+ ■B+→D0D0K+NR ■threshold comp

J=0 2/ndf = 185/5J=1 2/ndf = 7/5 J=2 2/ndf = 250/5

JP = 1-

■ ψ(4160) reflection

Spin Analysis


D*+K0s - Ds1(2536)+

D*+D0+ • D0 K-+

• D0 K--++

Charged tracks = good mass resolution

Low Q – close to threshold

Hep-ex 0607084

First width measurement !

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.


DsJ(2700) m= 2715 ±11 +11 -14 Mev/c2

= 115 ±20 +36 - 32 MeV /c2


Branching Fraction Ds+ → K+K-+

Identify two body Ds1Ds* Reconstruct 1 side (Ds1

(2536) or Ds*) Recoil mass is Mrecoil = √((√s-E (Ds1 ))2- p2(Ds1 ))

Measure Ds* peak or Ds1

→ Ds → K+K-+

→ D*0 K+ →

D*+ Ks0


Need further BKgd suppression so use cascade decays on both sides (not just tag)

Require additional with Ds1+

tag (Ds*+ → Ds+

Or K with D*s tag

recoil(Ds1) = Mrecoil(Ds1) - Mrecoil(Ds1)

B(Ds+ → K+K-+) = 4.1 ±0.4

±0.4% PDG 2006 5.2 ±0.9%

Branching Fraction Ds+ → K+K-+

D*s tag

Ds1 tag


Ds*+ → Ds+

Ds*+ → Ds+

recoil(Ds*K) GeV/c

recoil(Ds1) GeV/c


BB sample with one B fully reconstructed

Other BD(*)+,0 X• Observe Ds

+ and DsJ(2460) signals in the recoil mass, mX

Abs. BF’s for Ds+ ( +) and

DsJ(2460)

ee--DD**

ee++

BBrecoreco

BBsignalsignal

D*D*

XX

Hep-ex 0605036

Fitting the different modes and combining with previously

measured branching ratios

PDG


Branching Fractions - D+→+0, K+0

Improved BF measurements benefit D mixing analyses

Measure BF relative to D+→K-+ +

Reconstruct D+→h+0• Require D*+→D+0 • p*(D*) > 2.9 GeV/c• Use m sidebands to estimate peaking background

Efficiencies 5.9-8.5%

Sideband

region Signal

region

MC

Peaking bkg. from sideband

fit MC


Fits

Yield from un-binned maximum likelihood fitsD+→+0 D+→K+0

D+→K-++

Using BF(D+K-++) = (9.4 0.3)x10-2 from CLEO-C & PDG

124 fb-1

First Observation

>6.5

D+→K+0

D+→+0ref: D+→K-++

BF(D++0)=( 1.25 0.10 0.09 0.04(ref) ) 10-3

BF(D+K+0)=( 2.52 0.47 0.25 0.08(ref) ) 10-4

Hep-ex 0605044


Cabibbo suppressed 2 body decays of D0 show anomalous suppression of D0 -+ versus D0 K-K+ (~1/3)

Three body decays are poorly measured

Reconstruct D*+→D0+ m = m(D*+) - m(D0) • Fit K-+0 reflection in the -+0

and K-K+0 distributions

Recover non-uniform reconstruction efficiency weighting events with:

W = 1/efficiency no assumptions on Dalitz plot

structure

Branching Fractions - D0→ -+0, K-

K+0 D0→ K- +0

D0→ -+0

D0→ K- K+0

Belle±±Hep-ex

0608009


232 fb-1


Charm Baryon States

JP=3/2+(L=0)JP=1/2+

(L=0)

JP=1/2+

(L=0)

Strangeness

Charm

Isospin

Most C = 1 baryon ground states have been observed (except *c)

L > 0 states now being seen C = 2 QQq candidates observed by SELEX

(ccd)+ c+ K- +

(ccu)++ c+ K-

cc+ p D+K-

C= 1


c(2940)p D0

Search in continuum cc pD0 modes (D0K- K-)

Observe previously reported Λc(2880)+ (was observed in cby CLEO)

M = 2881.9±0.1±0.5 MeV/c2

Γ = 5.8±1.5±1.1 MeV

New state Λc(2940)+

• M = 2939.89±1.3±1.0 MeV/c2

• Γ = 17.5±5.2±5.9 MeV

• Confirmed by BELLE in Λc --> c

• First example of a charm baryon decay to a charm meson

No isospin partners seen in D+p so both Λc not c

Λc(2880)+ Λc(2940)+

Wrong sign D0p

Hep-ex 0603052

124 fb-1


First Observation ofc*(css)

c

Reconstruct c0 →

• a) -+ (-→K-) 156 +/- 15 events

• b) -+0 (-→K-) 92 +/- 26

• c) -+-+ (-→K-) 23 +/- 10

• d) --++-→K-) 34 +/- 15

Combine with MeV) Plot M(c

– Mc+ Mc

PDG Combined yield 105 ± 21 ± 6

M = M(c–Mc

= 70.8 ± 1.0 ± 1.1 MeV

Theoretical predictions 50 – 73 MeV

Hep-ex 0608055

124 fb-1 M(c– Mc

+ McPDG GeV/c2


Search for Doubly Charmed Baryons

SELEX reported evidence for cc

in c+K-+(+), D+pK-

Babar has looked for similar decays

cc+(+)c

+K-+(+) c c

+(+)c0+(+)

Belle searched cc

+(+)c+K-+

No evidence despite >106 c in B factories SELEX(1630 c )

Λc+K–π+ p*> 0

GeV/c

Λc+K–π+ p*>2.3

GeV/c

Λc+K–π+π+ p*>2.3

GeV/c

Λc+K–π+π+ p*> 0

GeV/c

Hep-ex 0605075

124 fb-1


Observation of Ξc

(2980)+ and Ξc (3077)+

Look for decays to Λc+ K- π+

No peaks in the wrong sign distribution

No peaks in the side band

Also seen in the isospin partners

Λc+→pK-π+

Mass(Λc+ K- π+)

Λc+→pK+π-

Mass(Λc+ KS

π-)

hep-ex/0606051,

Ξc (2980) and Ξc (3077) excited charm strange baryons.

Belle

Hep-ex 0607042


Summary

Large B factory charm samples still producing new charm meson and baryon discoveries

• DsJ(2860)+

• DsJ(2700)+

Plus refined masses, widths, BFs on previously discovered states

But no double charm Can expect much more in the coming years

c(2940)

Λc(2880)+

c*

Ξc(2980)+

Ξc(3077)+

Sep. 29, 2006 Henry Band - U. of Wisconsin 1 Hadronic Charm Decays From B Factories Henry Band...

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