Charm physics at Super B factories

P. Pakhlov (ITEP, Moscow)

On the need for a Super-tau-charm-factory Budker INP, Novosibirsk, September 27, 2008

Flavour Physics at B-factoriesGreat results by PEPII and KEKB BFactories. In 2001

Babar and Belle have discovered CP violation in B sector sin2β0;

Now β is measured with 1° accuracy. α and γ are measured with 10° accuracy. Many other CP violating channels including b→sqq Direct CP violation in B decays Rare B decays (B→τυ; B →K(*)ll) Observation of DD mixing New particles:

Excited charm mesons and baryons; Charmonium like states

Charm physics goal IPrecision test of the SM

(over constrain CKM together with B-physics) Fundamental parameters: mc; |Vcs|; |Vcd|Cancellation of QCD uncertainties: fB ; B→ form factorsInputs for CPV fits in B-decays: absolute Br’s; resonant structures in D decays; phases of Dalitz plot

50 ab-1

We dream to have this in 5-10 years

Not automatically reached by increasing the statistics

Charm physics goal IISearch for New Physics

CP violationLarge room for hunting of NP (could be ~1%); Direct CPV in CF & DCS decay: requires New Physics Direct CPV in SCS decay expect O(4) ~ 10 −3 from CKM matrix Indirect CPV

At least for some modes UL constrain the NP parameters

D0D0 mixing

Unfortunately, the only clear signature of NP in D-mixing (x >> y) is hardly realized in nature: Experiment: x ~ y ~ 1%

Rare decays

Charm physics goal IIIUnderstanding of QCD

Exotic states

Charm hadrons production

Potential models

(2S))

>10 new charmonium-like states – are they conventional cc-bound states?

large cross sections•e+e– J/ D(*+) X

•e+e– J/ ηc

e+e– machines at Y(4S)

B-manufactory B-factory B-superfactory

32

33

36

35

34

1985 1995 2000 2005 20101990 2015 2020

DORIS+ARGUS

CESR+CLEO

KEKB+Belle

PEP+BaBar

SuperKEKB

SuperB

year

Log(L)

cc cross section 1.3 nb (+ charm production from B decays Br(B→Hc)=110%)cc → D0 / D+ / Ds

+ / Λc+ / J/ψ = 1.2 / 0.45 / 0.22/ 0.12 / 0.001

Charm decay constants & FF with LQCD

No free parameters: αs, mu, md, ms, mc are fixed from other inputs.

mDs, mD, f, fK give consistency check.

B-factories: tag D* → D(,γ) → lυ by recoiling D and fragmentation;

548 fb-1

Add lepton and compute missing mass

D(s),K

γ

fDfDs

424pb-1

c-factories: reconstruct one Ds(*) at the

maximum of e+e−→ Ds*Ds x-section.

fD from experiment

Semileptonic decaysB-factories: tag D*+ → slow D→ lυ by

recoiling D and fragmentation; Good q2 resolution Dl/DKl separation using

kinematics

D0 → KlD0 → Kl

D0 →lD0 →l

m² GeV²

Vcs (Vcd) from DK()l Form-factors to constrain Vub

(Dl vs Bl assuming HQET)

D0→Kl +νD0→Kl +ν

D0→l +νD0→l +ν

D ,K

e

+ slow

D0

Rare decays: leptonic SM expectation 4×10-13; SUSY: 10-6

BaBar (122 fb-1) 1.3×10-6 (2004) CDF (360 pb-1) 5.3×10-7 (this year)

D0→reference

D0→4 evts

Super B factories can do this better than c-factories, but hadronic machines can do this as well

c

q

μ

u μ

Rare decays: D →Mll Loop contribution GIM suppressed; SM largest contribution is due to V→ll decays ~ 10-6

Present experimental sensitivity: ULs 10-4 −10-6

Distinguish NP from SM with dilepton mass spectrum or/and FB asymmetries

Forbidden: Lepton flavour (number) violation

D0 → e (< 8.1 × 10-7 BaBar); D+ → K+ e (< 3.7 × 10-6 BaBar)

D+→ − e+ e+(< 3.6 × 10-6 CLEO-c)

Rare decay: radiative

Br(D0→γ)=(2.73±0.30±0.36)10-5Br(D0→K*γ)=(3.22±0.20±0.27)10-4

Br(D0 → )=(2.60.70.2)10-5

Short distance FCNC decay is tiny

Long distance effect dominates:A(Vector Meson Dominance) ~ A(pole diagram) + interference Br ~ 10-4 − 10-6

K* helicity distribution is different from main bg

Belle (2004) 87 fb-1

BaBar (2008) 387 fb-1

Charm decay summary We do not discuss DD mixing and CP violation here (Bostjan’s

talk) Pure and semileptonic decays for fD and FF: Super B factory

(L=1036 ) can do this, but Super charm-factory (L=1035 ) can do this much better.

Rare decays: Super B factory (L=1036 ) can set the best UL for almost all the channels because of the largest D statistics. LHC can probably compete in D0→μμ.

Interesting channels, that are problematic for B factories: D0→KL for δK

CP tagged Dalitz analysis D0→KS

M=(3524.4±0.6±0.4) MeV/c2

(2S) → 0 hc → 0 c

CLEO, 2005

New charmonia

c(2S)e+e- J/c(2S)

M=(263012) MeV/c2

Belle, 2002B(KSK)K

Belle, 2002

M=(265410) MeV/c2

<55MeV

Charmonium table below DD threshold is complete!

B± →XK±

B0 →XK0s

X(3872)→(2S)γ

NEW

3.5σ evidence

M(+–)

Everything is surprising:M(–ℓℓ)- M(ℓℓ) GeV

N/1

0MeV

X(3872)

Phys.Rev.Lett. 91 262001 (2003)

X decays to J/, but very rarely (Belle 2004, BaBar 2006).

This observation fixes CX=+1, and confirms that in the X→J/ decay ()=. X decays to S), slightly more often (BaBar this year)

X decays to J/ with Br ~ Br (X→J/), confirms isospin violation. Fit to M() favours L=0 PX= +1.

X(3872) – the first in “X” series, introduces a new particle naming scheme: X, Y, Z ...

Belle, 2003

Br(X→J/γ) / Br(X→J/ π+π–) = 0.19 ± 0.07

Observed in the decay B+(J/)K+ MX=(3872.00.60.5) MeV/c2 in close vicinity of D0 D*0 threshold:

well above DD threshold but narrow:

unnatural spin-parity? In this case X→χcγ should be strong, not seen in the data. decay dynamics: M+- tends to peak around limit (J/ 0 is isospin violating decay)

Br(X→(2S)γ) / Br(X→J/π+π–) = 1.1 ± 0.4

MX – MDD* = (–0.4 0.7) MeV/c2 (PDG’07)

<2.3MeV at 90% C.L.

Fixing quantum numbers & more decay channels

Belle, 2004CDF, 2006

JPC=1++ corresponds to c1΄(23P1): c1΄→ J/ should be much stronger than

c1΄ → J/ (measured ratio ~0.2, expected ~30)

~100MeV/c2 lighter than expected.

JPC=2–+ corresponds to c2(11D2):

is expected to decay into hadrons rather than into isospin violating mode.

B K D0D*0

605 fb-1

D*→Dγ

D*→D0π0 Preliminary

Flatte vs BW similar result: 8.8σ

If X(3872) is virtual state, Flattè-like coupled channel effect X→J/ψ – the DD* threshold cusp with a sharp maximum at MD0 + MD*0 X→D0D00 – peak shifted by few MeV off MD0 + MD*0 Hanhart, Kalashnikova, Kudryavtsev, Nefediev

Angular analysis

Options for X(3872)

D0D*0 molecular state:

MX ~ MD0 + MD*0 is not occasionalJPC=1++ has been predicted (D0D*0 in S-wave)Isospin violation has been expected:

MD– + MD*+ is by ~ 8 MeV higher; >> binding energySmall X(3872) → J/ has been expectedAbsolute winner by popularity: > 50% of theoretical papers consider molecular model

D*0

D0¯

c

cu

u

Other options:Tetraquark (cq)(cq): predicts three states (cu)(cu), (cd)(cu), (cd)(cd) with a few MeV mass splitting between them. Hybrid (ccg) state.Threshold cusp (not in contradiction to the molecular model)

MX ~ MD0 + MD*0

is occasional?

- Voloshin-Okun JETP Lett. 23, 333 (1976): discuss existence of molecular-like states when mc→- De Rujula-Georgy-Glashow PRL, 38, 317 (1977) apply to (4040)- the idea was abandoned for many years- X(3872) enigmatic properties flashed back to the early ideas: Close-Page; Voloshin; Swanson; Tornqvist supposed that X(3872) is a

More statesarXiv:0711.2047

B →Y(3940)K

B0→Y(3940)K0S

Confirms Belle

PRL100, 20200 (2008)

M = 3942 ±6 MeV

tot =37 ±12 MeV

+7-6

+26 - 15

M= 4156 15

MeV

tot = 139 21 MeV

+25−20+111 −61

X(3940) → DD*

X(4160) → D*D*

6.0

5.5

PRL96,082003(2006)

5.3σ

c2′=23P2→DD

Some are identified (c2′), but M contradicts to potential modelsFor most of other the QN are unknown but in any case there is a contradiction to the predicted masses

eeJ/ & ee’ via ISR

Belle: confirms BaBar +higher mass peak

Belle: confirms BaBar +low mass enhancement

Peak positions in J/ & (2S) significantly different.

There is no place in the 1– – charmonium spectrum even for one state...

e+

e–e–

s=(Ecm-E

)2-p

2 1–– final state

(2S)

ICHEP2008

D*D*

DD*

(4

040)

(4

160)

Y(4

008)

(4

415)

Y(4

660)

Y(4

260)

Y(4

350)

DD

DDπ

Λc+Λc

–

?

PRD77,011103(2008)

PRL100,062001(2008)

σ(e+e–→open charm) via ISR

NEW

PRL98, 092001 (2007)

arXiv:0807.4458

Y(4260) mass corresponds to dip in D*D* cross sect. Y(4350) ... Y(4660) mass is close to Λc

+Λc– peak

Enhancement near 3.9 GeV in ee→DD coupled channel effect?

(3

770)

if Ruds=2.285±0.03

Durham Data Base

Y(4

008)

(4

040)

(4

160)

Y(4

260)

Y(4

350)

(4

415)

Y(4

660)

Belle: Sum of all measured exclusive contributions

helpful for understanding of Y?

PRL 100, 142001 (2008)

6.5

(2S))

B → KZ,Z(4430)+ → (2S)K=K–,K0

s(2S) →ℓ+ℓ–, J/

Br(B→ZK)×Br(Z→(2S)) = (4.1±1.0±1.3) 10-5

Br(B0→ZK+)×Br(Z→ψ(2S)π)<2.6x10-5 at 95% CL

Z(4430)+ first charged charmonium like state

M2 (

(2S

)),

(G

eV2 )

K*(890) K*(1430)

???

M2(K), (GeV2 )

K*(892)+K*(1430)

veto

548 fb-1

K*(892)+K*(1430)

K*(892)+K*(1430)

veto

M((2S)), (GeV )

4430

Preliminary

M = (4433±42) MeV= (45+18

-13+30

-13) MeV

M2 (

χ c1π)

, (G

eV2 )

M2(K), (GeV2 )K*(890)

K*(1430)

???

K*(1680)

K*(1780)

More Z+s (→χc1π+)B0→χc1π+K–; χc1 →J/ψγ Dalitz analysis: fit B0→χc1π+K– amplitude by coherent sum of RBW contributions• all known Kπ resonances (including κ)• K*’s + one (c1) resonance• K*’s + two (c1) resonances

Hypothesis of two Z’s

resonances is favored over one Z resonance at 5.7 Spin of Z1,2 is not determined: J=0 and J=1 result in comparable fit qualities

Cannot be

conventional charmonium

or hybrid

arXiv:0806.4098

two Z’s

Z1 Z2

without Z’s

M1=(4051±14+20–41) MeV/c2

Γ1=(82+21–17

+47–22) MeV

M2=(4248+44–29+180

–35) MeV/c2

Γ1=(177+54–39

+316–61) MeV

M(M

eV)

JPC

DD

Y(4260)

Y(4350)

Y(4660)Placed here by JPC

X(3940)

X(4160)

X(3872)

Y(3940)χc2’

Z+(4440)

Z+(4250)

Z+(4050)

χc1χc2

h’c

hc

χc0

(3770)

hc

J/

’

(4040)

(4415)

(4160)

Charmonium summaryMolecule?

(2S)Hybrid?

Tetraquark?

Charmonium below DD threshold have all been seen All new (neutral)charmonium(like) states above DD

threshold are at “wrong” masses. Some of them have “wrong” decays modes. Some are “wrongly” produced…

Are all peaks necessarily a state? Do we need exotic explanation to solve all these

problems? Can we solve all the problems at once?

BaBar has been stopped,Belle will be stopped soon…Most of questions have to wait for Super B factories

Look at the recoil mass against reconstructed J/ using two body kinematics (with a known initial energy)

Mrecoil = (Ecms- E J/ )2 - P J/ 2 ) See all the (narrow) states produced together with J/. The data shows unexpectedly charmonia states: c, c0, c(2S) Note: all recoil states are 0±+. The cross sections are ~10 times larger than expected

Double charmonium production

experiment

~10*theory

Belle(2002) BaBar (2005)

New states observation potential

B-manufactory

B-factory

B-superfactory

32

33

36

35

34

1985 1995 2000 2005 20101990 2015 2020

DORIS+ARGUS

CESR+CLEO

KEKB+Belle

PEP+BaBar

SuperKEKB

SuperB

year

Log(L)

D1(

2420

)D

2* (24

60)

D0* (

2400

)D

1(24

30)

Ds2

* (25

17)

Ds1

(253

0)Λ

c (262

5)Λ

c (259

3)

Λc (2

760)

Λc (2

880)

Λc (2

940)

Ωc

Ωc’

Ξc (3

070)

Σc (3

070)

Ds0

(231

7)D

s1 (2

420)

Ds?

(270

0)

Ξc ‘

90% PDG’s charm tablesis filled by B-machines

? ?? ? ?

Summary Besides the main goal of hunting/constrain New Physics in

B sector (precise CPV rare decays), Super B factories have a great potential to obtain interesting results in charm physics: charm decays, DD-mixing, charm(onium) spectroscopy, production.

The charm physics programs at Super B and Super charm-tau factories are complimentary.

T H A N K Y O U