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Exotic states with cc. Riccardo Faccini University “La Sapienza” and INFN Rome FPCP 2009 31 May 2009 Lake Placid, NY, USA. Quarkonium for Pedestrians. Quarkonium is a bound state of a quark and an antiquark Relevant quantum numbers: n,L,S,J Relationship with Parity and Charge Conj:

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Exotic states with cc

Exotic states with cc

Riccardo Faccini

University “La Sapienza” and INFN Rome

FPCP 2009

31 May 2009

Lake Placid, NY, USA


Quarkonium for pedestrians

Quarkonium for Pedestrians

  • Quarkonium is a bound state of a quark and an antiquark

    • Relevant quantum numbers: n,L,S,J

    • Relationship with Parity and Charge Conj:

      • P=(-1)L+1, C=(-1)L+S

    • Not all JPC allowed (e.g. 0+-,0--,1-+,2+- forbidden)

  • Decay Properties:

    • Below open quark threshold (e.g. (cc)DD) only electromagnetic or as suppressed decays allowed  mostly narrow states

    • Above open quark threshold (if DD decays allowed) mostly broad states


Charmonium state of the art

Charmonium: state of the art

same JPC as J/y but mostly D wave !

(2S+1)LJ

y(4160)

Increasing L 

M(MeV)

y(4040)

Open charm thr.

y(3770)

y’

Increasing n 

h’c

cc2

hc

cc1

cc0

J/y

hc

(pot. Models)

QWG: hep-ph/0412158

JPC

Basically all states below the open charm threshold are observed and explained


Beyond the quarkonium

Beyond the quarkonium

  • Search for states with 2 quarks+”something else”

    • New forms of aggregation

    • Expected but never identified!!!

  • Hybrids: qq+n gluons

    • Lowest state 1-+ (forbidden for quarkonium)

    • Dominant decay HDD**

  • Tetraquarks: [qq’][qq’]

    • Large amount of states

    • small widths also above threshold

  • Molecules: M[qq]M[q’q’]

    • Smaller number of states but still small widths also above threshold

  • Search for resonances:

  • with non-quarkonium JPC

  • unnaturally small widths

  • not null charge: would be clear indication of something new going on


Measuring the quantum numbers

Measuring the quantum numbers

gISR

e+

X

  • Production:

    • ISR only produces with same quantum numbers as the photon (JPC=1--)

    • gg only produces with C=+

    • Double charmonium production

      e+e- g*Xcc1Xcc2

      Possible only if quantum numbers of the two

      charmonia can be combined to give a 1--.

  • Decay:

    • Angular distributions of decay products depend on JP.

    • Selection rules

      • Conservation of J

      • Conservation of P,C in strong and electromagnetic decays

e-

e+

e+

X

e-

e-


The new zoology

The new zoology

X(3872)

The 1-- family

The charged states

hot off the press


X 3872 known facts

X(3872): known facts

  • Decays

    • XJ/y pp (original observation)

      • Maybe J/y r

    • BF(XJ/y w)~ BF(XJ/y r)

    • Full angular analysis from CDF

    • XJ/y g

      Implications:

      • C(X)=+1

      • C(pp in J/y pp decay)=-1

      • I(pp)=L(pp)=1  consistent with J/yr decay hypothesis

      • JPC=1++ or 2-+ from angular analysis

  • Production

    • only B decays so far

    • No prompt e+e- production observed (BaBar arXiv:0707.1633)


The x 3872 puzzle

The X(3872) puzzle

Not matching any predicted state!

Above DD threshold (allowed): should have large width but it is narrow

Charmonium highly suppressed decay into J/y r (isospin violation)

y(4160)

(2S+1)LJ

Increasing L 

M(MeV)

Open options

  • DD* molecule

    • Right above the threshold

    • favors DD* decay over J/ypp over J/yg (as observed)

  • Tetraquark

    • Explains small width

    • Predicts a set of 4 states (2 charged and 2 neutral).

      • Finding these states is critical

y(4040)

X(3872)?

Open charm thr.

y(3770)

Increasing n 

h’c

y’

cc2

hc

cc1

cc0

J/y

(pot. Models)

hc

JPC


Are there two x j ypp

Are there two XJ/ypp ?

arXiv:0807.3699

  • CDF with largest sample investigates the mass distribution for two resonances closeby

Fitted mass difference as a function of first gaussian fraction

DM<3.2 MeV @90%C.L.


Is the x in b 0 and b decays the same

arXiv:0809.1224

Is the X in B0 and B+ decays the same?

B± XK±

B0 XKS

X  J/ypp

More in

Phys.Rev.D77:111101,2008

Consistent with one state, equally present in decays


X 3872 d 0 d 0

X(3872)D0D*0

  • Belle [PRL 97, 162002 (2006)] observed X(3872)D0D0p0

  • Confirmation and integration from BaBar in BDD*K[PRD 77, 011102(2008)]

  • Most recent result from Belle

D*D0p0

D*D0g

arXiv:0810.0358


X 3872 mass

X(3872) mass

[my extrapolation]

Poor agreement among mass measurements:

XJ/ypp and XDD(*) differ by ~3.5s

TWO STATES? X(3872) & X(3876) ?

Predicted by tetraquark model

(but why so close to threshold?)


The new zoology1

The new zoology

X(3872)

The 1-- family

The charged states

hot off the press


The 1 family

The 1-- family

Several resonances observed in e+e- YgISR(certainly JPC=1--)

Y(4260)J/ypp

Confirmation + J/yp0p0:

CLEO PRD74, 091104 (2006)

CLEO-c PRL 96, 162003 (2006)

A new state: Y(4260)

PRL 95, 142001 (2005)

Yet another state Y(4350)

PRL 98, 212001 (2007)

Y(4350)y(2S)pp


The youngest of the 1 family

The youngest of the 1-- family

PRL99, 142002 (2007)

5.8s

Present in low stat in BaBar’s publication

Zoomed

BaBar

Yy(2S)pp


Exotic states with cc

Y(4260)

PRL99, 142002 (2007)

arXiv 0808.1543

DECAY PROPERTIES

f0 dominating?

Threshold effects?

Y(4660)

Y(4350)


X 4630 or y 4660 l c l c

PRL101,172001 (2008)

X(4630) [or Y(4660)?]LcLc

  • Y(4660) good candidate for a LcLc bound state

  • Search for ISR e+e- LcLcg events

Right sign p

CFR

Wrong sign p

In the discovery mode

Assuming same state as y(2S)pp

!


Isr search for y 4260 d d

ψ(3770)

ψ(3770)

DD

DD

ψ(4415)

ψ(4415)

ψ(4040)

ψ(4040)

ψ(4160)

ψ(4160)

G(3942)

G(3942)

ψ(4260)

ψ(4260)

D*D

D*D

D*D*

D*D*

ISR search for Y(4260)→ D(*)D(*)

Y(4260) is 1-- charmonium state  should decay predominantlyto DD, D*D, and D*D*

BABAR: PRD 79, 092001 (2009), 384


1 family recap

1-- family: recap

Only seen in y(2S)pp

(2S+1)LJ

  • Not matching any potential model prediction

  • Too narrow

4660

M(MeV)

4350

y(4160)

4260

y(4040)

Open charm thr.

y(3770)

y’

“new physics”?

4260 can be fit by a tetraquark model (decaying into J/yf0 …) or a hybrid (with gpp)

J/y

(pot. Models)

JPC

1--

1--


The new zoology2

The new zoology

X(3872)

The 1-- family

The charged states

hot off the press


The z 4430

The Z(4430)+

  • Charged states a strong prediction of the tetra-quark model

  • First observed by Belle in PRL100, 142001 (2008)

  • Search for Z±

    J/y or y(2S) + p±

    In Byp±K decays

    M=4433±4±2 MeV

    G=45+18-13+30-13 MeV

121±30 evts , 6.5 s


Criticisms to discovery analysis

Criticisms to “discovery analysis”

  • Only “global”

    efficiency

    correction

  • Poor

    treatment of 3-body decays (cut away dominant resonances – no interference/reflections)

  • Arbitrary choice of background shape

VETOES


Babar analysis

arXiv:0811.0564

BaBar Analysis

  • Event-by-event efficiency correction

  • Describe the Kp system in detail

    • Mass

    • Angular distributions fitted with Legendre Polynomials


Comparison of babar background with data

Comparison of BaBar background with data

Same “veto” definition as Belle


Babar results

BaBar results

  • Fitting without vetoes

    m=4476±8 MeV/c2; Γ=32±16 MeV; signal size: 2.7σ

    [offset of 43±9 MeV w.r.t. Belle]

  • Same vetoes as Belle

    m=4439±8 MeV/c2; Γ=41±33 MeV; signal size 1.9σ

  • Conclusions:

  • mistreatement of background might enhance significance

  • veto might bias signal mass measurement


Belle dalitz plot analysis

arXiv:0905.2869

Belle Dalitz Plot Analysis

  • Belle’s observation confirmed, but errors increase

  • Including y(2S)W

W=

  • m=4443+24-18 MeV

  • Γ=109+113-71 MeV

CFR. BaBar excludes 3.1 10-5 @90%C.L.


Z 1 and z 2 c c1 p

PRD 78, 072004 (2008)

Z1 and Z2cc1p

Same analysis strategy

b+d


Summary of charged states

Summary of charged states

The 1– family

(2S+1)LJ

M(MeV)

Z(4430)

y(4415)

y(4160)

Z(4250)

Z(4050)

y(4040)

Open charm thr.

y(3770)

h’c

y’

cc2

hc

cc1

cc0

J/y

(pot. Models)

hc

JPC


The new zoology3

The new zoology

X(3872)

The 1-- family

The charged states

hot off the press!!


The 3940 family

The 3940 family

PRL 94, 182002 (2005)

PRL 96, 082003 (2006)

PRL 101, 082001 (2008)

PRL 98, 082001 (2007)

ZDD

YJ/yw

XDD*


New belle peak in gg w j y

New Belle peak in ggwJ/y

M: 3914  3  2 MeV,

G: 23  10 +2-8 MeV,

Nres = 55  14 +2-14 events

Signif. = 7.7s

Preliminary


The 4 states near 3940

The 4 states near 3940

Mass(GeV)

Range: (s(stat.)+s(sys.))

Y(3940)

Belle

X(3940)

Better analysis of the J/y w mass spectrum needed!!

Z(3930)

Good overlap with

BaBar “Y(3940)” values

Would allow only the 0++ assignment

This X(3915)

Width(GeV)


Y 4140 from cdf

Y(4140) from CDF

Search for BYK YJ/yf

arXiv:0903.2229

14  5events

M=m(+-K+K-)-m(+-)

M: 4143.0  2.9  1.2 MeV,

G: 11.7 +8.3-5± 3.7MeV,

Signif. > 3.8s

Lowest lying hybrid, expected at m~4200MeV

Possible JPC=0++,1-+,2++

Another ‘edge’ state, better candidate molecule


Summary

More on the 1- - family

Summary

The charged candidates

(2S+1)LJ

M(MeV)

Z(4430)

y(4140)

y(4415)

y(4160)

Z(4250)

Z(4050)

X(3872) never ending story

y(4040)

X

Z

Y

Open charm thr.

y(3770)

One more member of

the 3940 family

h’c

y’

cc2

hc

cc1

cc0

J/y

(pot. Models)

hc

X(4160)

New state from CDF

Good Hybrid candidate

JPC


Outlook

Outlook

Plenty of states seen with low stat and in only one channel  next generation [SuperB(elle)?] needed


Backup

backup


Confirmation of y 3940 b k w j y

G. Cibinetto, talk at this conference

Confirmation of Y(3940) (BKwJ/y)

p+p-p0

BYK

preliminary

  • New result, based on 350 fb-1:

  • Belle’s evidence for BYK, YJ/ confirmed

  • ~30MeV lower mass than Belle’s

  • Narrower width

  • Clear demonstration of decay into w

  • Preliminary BF estimate similar to Belle’s (~10-5)

B0YKS

B0/B

Y(3940) closer to X(3940)

Can they be the same state?

Isospincons.

M(J/y w) (GeV)


X 4160 d d

Obtain J/yD(*)D(*)samples through kinematic separation, look at m(D(*)D(*))after background subtraction:

X(4160) D*D*

e+ e-J/y D(*)D(*)

BELLE-CONF-0705

M = 3942 ±6 MeV

tot =37 ±12 MeV

Nev= 52 ±11

reconstructed

Inferred (Recoil mass)

Something’s here, but it’s not X(3940)

3.8 

X(3940)

is still there, 6.0s

J/y D+

D*

D*D*

D

Number of events

M(DD)

M(DD*)

X(4160)

claim: new state

5.5 

J/y D*+

X(3940)

Cross-check

D*

D

M(D*D)

M(D*D*)

M = 4156 ±15MeV

tot = 37 ±21MeV

Nev= 24

+25

- 20

+111

- 61

One more particle to explain …

JCP=0-+ not excluded (hc(3S))

+12

- 8


Just charmonium states

“Just” charmonium states?

(2S+1)LJ

  • Poor match with predictions

    • Above threshold?

  • If X≠Y, difficult to explain absence of Yopen charm

    • Hybrid?

M(MeV)

Z

Y=X(3915)

X

Open charm thr.

y(3770)

h’c

cc0

cc1

cc2

hc

(pot. Models)

JPC


Fits to j y kk invariant mass

Fits to J/y KK invariant mass

‘Standard ‘ y(4415) + 1 BW:

M = (4875±132) MeV

G = (630±126) MeV

single BW:

M = (4430±38) MeV

G = (254±49) MeV


Thresholds and new states

Thresholds and new states

Y(4660)

Y(4350)

Y(4260)

X(4160)

XYZ(3940)

X(3872)


Cleo and belle on 4260

CLEO and Belle on 4260


Search for x 3872 j y g in continuum

Search for X(3872)J/yg in continuum

386fb-1

arXiv:0707.1633

J/ production observed in continuum while no evidence of c states.

cc1

X(3872)

c1,2 or X(3872)

cc2

X>2 ch

c production is consistent with the expected contributions from prompty(2S) production feed-down tocc: no evidence of prompt c1,2

No evidence of X(3872) production in e+e- annihilation.


Experiments

Samples used in results

Experiments

58MJ/y, 14M y(2S)

  • e+e-Charmonium (CLEO-c, BES-II)

    • L~1033/cm2/s

    • E=3.0-4.3 GeV

  • e+e- Y(4S): (BaBar, Belle, CLEO)

    • L~1034/cm2/s

    • Charmonium in B decays, ISR and gg production

      • Capability to measure JPC also in production

  • pp colliders (CDF, D0)

    • High Xsection  copious production

    • Extremely high backgrounds

3M y(2S), 1.8 M y(3770)

1.5M Y(1S),1.9M Y(2S),

1.7M Y(3S),9M Y(4S)

657M Y(4S)

383M Y(4S)

1.3 fb-1

2.4bf-1

  • Disclamers:

  • time is very short

  •  could not cover everything

  • theory statements are indicative


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