recent results on charm hadrons from babar and belle

Ruslan Chistov ▪ Recent Results on Charm hadrons from BaBar and Belle (27/11/07, ITEP)1

Recent Results on Charm Recent Results on Charm Hadrons from BaBar and BelleHadrons from BaBar and Belle

▪ Introduction ▪ Evidence for D0-D0 mixing ▪ Measurement of Ds and fDs

▪ Observation of new excited charm baryons c(3055/3123)+

▪ Summary

Ruslan Chistov (ITEP)

Сессия Отделения Ядерной Физики РАН , Физика Фундаментальных Взаимодействий, ИТЭФ 27/11/07


Recent Recent Results on Results on

Charm Charm Mesons :Mesons :


DD00-D-D00 mixing in the SM mixing in the SM

Unlike mixing in K0, B0 and B0s systems, D0 system provides test for neutral meson mixing with down type quarks in the box.


KK yxx sincos

2

22

4t

yxtRyRet DD

tWS

KK xyy sincos

Strong phase difference between CF and DCS

• Wrong sign (WS) hadronic decays e.g. K+ - ( K+ - 0, K+ - - + )t-dependent analysis required to disentangle mixing and DCS contributions

yCP= y if no CP violation

• Lifetime difference e.g. D0 K+K- (+) vs D0 K- + (0) 0/ + = 1 + yCP

RM = 1/2(x2 + y2) 2tRet M

tWS

• Wrong sign (WS) semileptonic decays D0 K+l-

• Dalitz plot analysis D0 KS - + t-dependent analysis: interference of DCS and mixing e.g. D0 K*+- CP final states e.g. D0 KS 0 (+)

DD00-D-D00 mixing: experimental methods mixing: experimental methods


DD00-D-D00 mixing: Status 2006 mixing: Status 2006

RM<0.040 %

D0 K+- Phys.Rev.Lett.96:151801,2006.

400fb-1

Wrong sign (WS) hadronic decays: K+ -, K+ - 0, K+ - - +

t-dependent analysisto disentangle mixing and DCS

Phys.Rev.Lett.97: 221803,2006.

D0 K+- 0

D0 K+- +-

230.4fb-1

Many hints of D0 D0 mixing: ~2.1 Belle D0K ~2.3 BaBar D0K2/K3 ~2.2 Average yCP (PDG’06)


DD00-D-D00 mixing mixingfrom BaBarfrom BaBar

384fb-1

hep-ex/0703020v1

403090candidates

WS

poin

ts:

data

– n

o-m

ixin

g fit

curv

e : ”

mix

ing

fit”

– “n

o m

ixin

g fit

”Fi

t with

mix

ing

is b

ette

r mat

ch to

dat

a!


DD00-D-D00 mixing from BaBar: Results mixing from BaBar: Results

mixing CL contours

3.9 no-mixing point

No CPV

x’2 and y’2 CL contours • calculated from the change in log likelihood • include systematic errors

x’2 = - (0.220.300.21)x10-3

y’ = (9.74.43.1)x10-3


DD00-D-D00 mixing at Belle: y mixing at Belle: ycpcp

Measure relative lifetime difference: D0 K-+ and D0 K+K- (+ -)

mixing parameter:

yCP= y· cos - 1/2AMx· sin CP conservation: AM = sin = 0 ; yCP= y = /

Search for CPV by measuring A = 1/2AMy· cos - x· sin


DD00-D-D00 mixing at Belle: y mixing at Belle: ycpcp results results

Visual demonstrationof non-zero y:


DD00-D-D00 mixing at Belle: mixing at Belle:Dalitz analysis D0 K0

S -+

Study self-conjugate decay

D0 K0S -+

t-dependence of Dalitz plot distribution provide direct access to x and y!!!

Decay amplitude assuming M = M (no CPV):

t - dependence is contained in

for D0 m2= m2(KS) , for D0 m2

= m2(KS)

Strong phase difference between CF and DCS amplitudes fixed by Dalitz fit!


Belle results on Belle results on Dalitz analysis D0 K0

S -+

disfavor no-mixing disfavor no-mixing x=y=0 pointx=y=0 point

with significance with significance 2.2 2.2


DD00-D-D00 mixing measurements mixing measurements averageaverage


Measurement of Ds+ + and fDs

at Belle


Reconstruction ofReconstruction of Ds+ +


Measurement of Ds+ + and fDs

at Belle (results)

!


Recent Recent Results on Results on

Charm Charm Baryons :Baryons :


Λc+K-π+

Ξc(3080)+

NEW Λc+K-π+

Ξc(2980)+

NEW Ξc(3080)+

Ξc(2980)+

Λc+Ksπ-

Ξc(3080)0 NEW

PRL97,162001

hep-ex/0607042

BaBar confirmed

Measurements of M and Γ are consistent

New decay mechanism: s-quark → meson

Observation of new excited Observation of new excited charm strange baryons at Belle charm strange baryons at Belle


Observation of Observation of ΞΞcc(3055)(3055)++ and Evidence for and Evidence for ΞΞcc(3123)(3123)++ at BaBar at BaBar

Ξc(3080)+

Ξc(3080)+

Ξc(2980)+

Σc(2455)++K-→Λc+K-π+

Σc(2520)++K-

Ξc(3055)+

NEW

Ξc(3123)+

evidence

hep-ex/... (preliminary)

For all new c

More experimental studies to assign JP.

Mass D-wave excitations ?Ξc(2980) 1/2+, 3/2+,.. Ξc(3080) 5/2+,..


Discussion of New Discussion of New cxcx States States

Observed Properties:Observed Properties: •Charm and strange quarks in the final state (Λc

+ and K-);•These new charm baryons have *large masses (largest in grand family of charm baryons), *finite widths;

•Neutral partners also observed not double charm baryonsnot double charm baryons

Most natural interpretation: excited charm strange baryonsexcited charm strange baryons

which could be D-wave excitations. Possible JP are 1/2+(or 3/2+) and 5/2+ (H.-Y.Cheng, C.-K.Chua, hep-ph/0610283; J.L.Rosner, hep-ph/0612332)

Note: Note: Not seen in M( Not seen in M(ΛΛcc++KK--) and M() and M(ΛΛcc

++KK--++--) spectra!) spectra!


Observation of cxcx(2980)(2980)+/0+/0 cc*0/+*0/++/- +/-

at Belleat Belle

Ξc(2815)+

Ξcx(2970)+

No Ξcx(3080)+

M(Ξc(2645)0π+) M(Ξc(2645)+π-)

??

Ξc(2815)0

Ξcx(2970)0

No Ξcx(3080)0

??

Search for another, “natural” channel for the new states cx

Pre

lim

inary


Observation of Observation of ΛΛcc(2940)(2940)++ and and ΛΛcc(2880)(2880)++DD00pp

c(2880)+

c(2940)+

BaBar Belle

M(M(ΣΣcc(2455)(2455)0,++0,++ππ±±))

c(2880)+

c(2940)+

New decay mechanism of excited New decay mechanism of excited ΛΛcc ! !


Study of Study of BB++→→ΛΛcc++ΛΛcc

--KK++ by by BaBarBaBar(preliminary)(preliminary)

Originally, B+→Λc+Λc

-K+ decay has been observed by Belle

BaBar: confirmation, resonant structure.BaBar: confirmation, resonant structure.

Λc+K-

BaBar “More data are needed before firm conclusions can be drawn.”

Excited Ξc? not seen in continuum

Λc+ Λc

- K-

mbc (GeV/c2)

NEW

PRL97,202003 (2006)

phase-space

sidebands

B mesonsignal


SummarySummary on New Charm Baryonson New Charm Baryons

c(2880)+ c and D0p (!), c(2940)+ mostly to D0p, (csuppressed)

cx(2980) c* and cK (cK),

cx(3080) only to cK (c(*)K),

(no signal for c*)

cK threshold

D0p threshold

New charm baryons with new decay mechanism were discovered by BaBar and Belle:


Summary Summary

• This year D0-D0 mixing results :• New D0K+- study at BaBar: 3.9 of (x’,y’) (0,0) (past year at Belle: 2.1 of (x’,y’) (0,0)• New Dalitz analysis D0 K0

S -+ at Belle: 2.7 of (x,y) (0,0)• New yCP measurement at Belle: 3.2 of y 0 (past year at BaBar: 1.9 of y 0)

● Combination of existing D0-D0 mixing results established at ~5σ

● New measurement of fDs fromBelle in good

agreement with previous results and LQCD ● A lot of new charm baryons observed : waiting interpretation from theory


Back up slidesBack up slides


Integrated luminosity

May ‘99

KEKB asymmetric-energyKEKB asymmetric-energy e e++ee-- collider and Belle detector collider and Belle detector

> 1 fb-1/day

e+e- Y(4S)

{ll, cc, qq}

Not only EWP and CP!

> 730 fb-1


Angular analysis of Angular analysis of DDs1s1(2536)(2536)++DD*+*+KK00

ss at Belle at Belle


RESULT:

Angular analysis of DAngular analysis of Ds1s1(2536)(2536)++DD*+*+KK00ss

at Belle (cont’d)at Belle (cont’d)



BaBar confirmed also Ξc(3080)0

Λc+K-π+

Ξc(3080)+

NEW

Λc+K-π+

Ξc(2980)+

NEW

Ξc(3080)+

Ξc(2980)+

Λc+Ksπ-

Ξc(3080)0 NEW

PRL97,162001

hep-ex/0607042

BaBar confirmed


New decay mechanism:s-quark → meson.


RosnerChen, Chua, PRD75, 094017Garcilazo, Vijande, Valcarce, JPG34, 961Chen, Chen, Liu, Deng, Zhu, PRD75, 094017Ebert

Observation of Observation of new excited charm strange baryonnew excited charm strange baryon

at Belle and BaBar at Belle and BaBar


Observation of Observation of ΞΞcc(2980) and (2980) and ΞΞcc(3080) (3080) by Belle by Belle

resonant structure


BaBar confirmed also Ξc(3080)0

Λc+K-π+

Ξc(3080)+

NEW

Λc+K-π+

Ξc(2980)+

NEW

Ξc(3080)+

Ξc(2980)+

Λc+Ksπ-

Ξc(3080)0 NEW

PRL97,162001 hep-ex/0607042

BaBar confirmed


New decay mechanism:s-quark → meson.


RosnerChen, Chua, PRD75, 094017Garcilazo, Vijande, Valcarce, JPG34, 961Chen, Chen, Liu, Deng, Zhu, PRD75, 094017Ebert


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