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Hadron Spectroscopy at BABARBY

Usha Mallik (University of Iowa)

Representing

The BaBar Collaboration

The International Light-Cone WorkshopJuly 7, 2005

Cairns, Australia

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Topics:

Hadron Spectroscopy:– Ds (cs) States : Inclusive and Exclusive studies

– Double Charmonium Production; the X and the Y

– Pentaquarks– Charmed Baryon studies

Summary What can we learn from each other ?

3Plan to Double Dataset by Next Summer

The BABAR Detector at PEP-II and the Dataset

BBSee )4(

Ecm = 10.58 GeV

And Much More

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DSJ (cs) Spectroscopy

New States DSJ(2317)+ and DSJ(2460)+ – First Observed Inclusively in e+e- Collisions

Previously Established States with Likely JPC

DS (2112)+ 1-(+) S-Wave (c and s spins aligned)

Ds also DS 0

DS(2536)+ 1+(+) P-Wave (needs

confirmation)D*(2010)+K0

D*(2007)0K+

DS(2573)+ 2+(+) D-Wave (consistent

with)D0K+

Ground State DS(1969)+: JP=0-, c and s spins opposite, in S-

wave

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B(DsJ (2460) Ds

0)

B(DsJ (2460) Ds

* 0) 0.21 (90% CL)

Belle 87 fb-1

B(DsJ (2460) Ds

0)

B(DsJ (2460) Ds

0) 0.11 (95% CL)

BaBar 125 fb-1

Discovery

Ds* Ds

Discovery of DsJ Statese+e- cc DsJ + X

DsJ(2317)+ Ds+0 DsJ(2460)+ Ds

*+0

M(2460) – M(2112)

BABAR, BELLE, CLEO mutually confirm, also CDF (2317)

Caution: These Decays cross-feed

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• Decays violate isospin: mixing

• Look for radiative and dipion transitions

• If is , expect is forbidden

is forbidden

• If is , expect is allowed

is allowed

0 0

DsJ*(2317)

DsJ*(2317) Ds

0

DsJ*(2317) Ds

DsJ (2460) Ds

DsJ* (2460)

DsJ (2460) Ds

1

...3,2,1,0)2317( 0* PssJ JDD

1 )2460( 0* PssJ JwaveSDD

2,1,0PJwaveP(also D-Wave)

(for a conventional meson)

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DsJ(2460): 0± excluded

Search for DsJ→Ds

DsJ (2460)

B(DsJ (2460) Ds)

B(DsJ (2460) Ds 0)

0.3750.0540.057

B(DsJ (2317) Ds)

B(DsJ (2317) Ds 0)

0.17 (95% CL)

BaBar 125 fb-1

Excludes 0± if present

DsJ(2317): compatiblewith 0+

BABAR: PRD 69 (2004) 031101 (R) ; BELLE : PRL 92 (2004) 012002

BABAR

B(DsJ (2460) Ds)

B(DsJ (2460) Ds* 0)

0.550.130.08

B(DsJ (2317) Ds)

B(DsJ (2317) Ds 0)

0.05 (90% CL)

Belle 87 fb-1

)2317( No sJD

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DsJ(2460) → Ds0Kinematics

DsJ* (2317)reflection

Ds*

reflection

DsJ (2460)

high Ds* sideband

low Ds* sideband

DsJ(2460)

hep-ex/0408067

BABAR

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BELLE: PRL 91 (2003)262002

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Exclusive Production of D*SJ in B ->DSJ

(*)+ D(*)

Kinematic Constraints Help, Even though Lower Stats

Reduces Backgrounds

Measure Ratios of Branching Fractions

Measure Br

Well-defined Initial State

Test DSJ(*) Spin Assignments

Reconstruct one B: other is a B for Study

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B DsJ (*)+ D(*)

2*4/ BES psm

BABAR: PRL 93 (2004) 181801Data sample: 122 million B pairs

DDsJsJ**(2317)(2317)++

DDss00

DDsJsJ(2460(2460))++

DDss**00

DDsJsJ(2460(2460))++

DDss

mmESES mm((DDsJsJ)

Full reconstruction of the exclusive decay

Sum over charged and neutral B’s 112 ± 14 events

139 ± 17events

020.0045.0274.0

))2460(.(.

))2460(.(.0*

sDDFB

DDFB

sJ

ssJ

We measure:

2/* sEE B

mmESES mm((DDsJsJ)BABAR

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B DsJ (*)+D* Results

B.F. (10-3) DsJ*(2317)+ Ds0 DsJ(2460)+ Ds*0 DsJ(2460)+ Ds

B0 1.5 ± 0.4 ± 0.2(+0.5-0.3) 5.5 ± 1.2 ± 1.0(+1.9-1.2) 2.3 ± 0.3 ± 0.3(+0.8-0.5)

B+ 0.9 ± 0.6 ± 0.2(+0.3-0.2) 7.6 ± 1.7 ± 1.8(+2.6-1.6) 1.4 ± 0.4 ± 0.3(+0.5-0.3)

B.F. Productsfor BDsJ

(*)+D*

m(Ds+0) m(Ds

*+0) m(Ds)B0 B0 B0

B+B+ B+

DsJ(2317)DsJ(2460) DsJ(2460)

BABAR

BELLE: PRL 91 (2003) 262002 Data sample: ~124 million B pairs

in agreement with Belle results

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B DsJ (*)+D Results

B.F. (10-3) DsJ*(2317)+ Ds0 DsJ(2460)+ Ds*0 DsJ(2460)+ Ds

B0 1.8 ± 0.4 ± 0.3(+0.6-0.4) 2.8 ± 0.8 ± 0.5(+1.0-0.6)

0.8 ± 0.2 ± 0.1(+0.3-0.2)

B+ 1.0 ± 0.3 ± 0.1(+0.4-0.2) 2.7 ± 0.7 ± 0.5(+0.9-0.6)

0.6 ± 0.2 ± 0.1(+0.2-0.1)

B.F. Productsfor BDsJ

(*)+D

in agreement with Belle results

m(Ds+0) m(Ds

*+0) m(Ds)

B0 B0 B0

B+ B+ B+

DsJ(2460) DsJ(2460)DsJ(2317)

BABAR

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• Two body decay BDDSJ forces DSJ to populate helicity zero only

• Analyze angular distribution (cos h) of daughter of DSJ

• BELLE Finds from Angular Distribution – DSJ(2317)* J = 0 (Preliminary)

hB DsJ

D

0

Ds(*)

–

Spin Analysis of B DDSJ*

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BDsJ(2460)+D

DsJ+

(2460)

Ds

h

J=1 (2=4.0/4) preferred to J=2 (2=36.4/4)

Data points from m(Ds fits corrected for detector acceptance and efficiency

J=2J=1

confirms Belle measurement

BABAR

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e.g. Godfrey-Isgur model

S-wave P-wave

Ds+

Ds*+

Ds1(2536)+

DsJ (2573)+

Ds0(2317)

Ds1(2460)

DsJ*(2317)+, DsJ (2460)+

– Observed by BaBar, Belle and CLEO – Unexpectedly below threshold for DK and D*K, respectively – Consistent with P-wave cs states but other interpretations not ruled out– If cs, observed decays

• DsJ*(2317)+ Ds

+

• DsJ (2460)+ Ds*+

are isospin violating narrow

– DsJ (2460)+ Ds+

also observed (and used to

determine J)

Taking Stock of cs States

Several other explanations exist e.g. Molecules or Hybrids

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New Charmonium-like States

X(3872) J/π+π-

Average Mass 3871.9 ± 0.5 MeV

Narrow < 2.3 MeV @ 90% CL

(D0D*0 threshold at 3871.3 ± 1.0)

CDFPRL 93 072201 (2004)

BELLE PRL 92 262001 (2003)

BABARhep-ex/0406022

D0PRL 93 162002 (2004)

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B+ X(3872)0K+ Reconstruction

Recent Update:

BELLE (256 fb -1) hep-ex/0505038, BABAR hep-ex in preparation

Background from B decays to same final state J/K

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About X(3872)

• Search for a Charged Partner

From 212 fb -1 Data BABAR Observed No Signal for X-

Phys. Rev. D71 : 031501, 2005

B(B0 X-K+, X- J/ π-π0) < 5.4 X 10 -6 @ 90% CLB(B- X-KS, X- J/ π-π0) < 11 X 10 -6 @ 90% CL

• Charmonium State : no isospin partner expected (data)

• Molecule State (?) : highly suppressed B0 X(3872) predicted

• Diquark-antidiquark State : different masses of X(3872)

in B0 and B+ decays predicted, |M| > 5 MeV

E. Braten, M. Kusunoki hep-ph/0412268

L. Maiani, F. Piccini, A.D. Polosa, V. Riquer PRD 71(2005) 014028

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B0 X(3872)0KS Reconstruction

Background

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Other searches for X(3872)

Search for X(3872) in events with initial state radiation (if JPC = 1-- )

Search for X(3872) in B X(3872)K in the spectrum recoiling against K from the B decays (with the other B fully reconstructed):

B(X(3872) in B X(3872)K, X(3872) J/) < 3.2 X 10 -4 at 90% CL and so, BF(X(3872) J/+-) 4.3 %

mes of all the exclusively reconstructed B

mES : B mass using beam energy

Use BABAR-BELLE average BF(B+ X(3872)K+, X(3872)J/) = (13.2 2.2) x 10 -

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PRD 71 (2005) 052001

BABAR

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BELLE: 256 fb -14.0

C= +1 favored

hep-ex/0505037

X(3872) : +- Invariant Mass Distribution

BELLE: hep-ex/0505038BABAR: hep-ex in prep.

Di-pion mass consistent with 0+- , again C =+1 ; S-wave J/ favored: J++ favored over J-+

Isospin violating: predicted

D0D*0 molecule, Swanson PLB 588 (2004) 189, Törnqvist PLB 590 (2004) 209

Also X(3872) π+π-π0J/

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X(3872): BELLE Finds Data Disfavors 0++ and 2++, Leaving 1++

cc ? 1++ is c1’

X(3872) is too light

M[Ge

DDThreshold

3872

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}C=+1 }C=-1

c , c , c(2S)J/, (2S)

G. T. Bodwin, E. Braaten & J. Lee

PRD67, 054023 (2003)

Study double charmonium in e+e- annihilation

Double Charmonium Production

Theorists predict the cross sections of the two processes to be comparable

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Reconstruct J/ or (2S) and Look at Recoil MassBABAR: 124 fb -1, hep-ex/0506062

c

c(2S)

c0

BELLE: PRD 70 (2004) 071102

BABAR

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Double Charmonium Production from BELLE

From BELLE

Evidence of X(3940): 4.5

m = 3940 ± 12 MeV, < 96 MeV at 90% CL

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8 : 253 fb -1 with 59 ±11 Events

A Near-threshold J/ Mass Enhancement in B KJ/ at 3940 MeV/c2

BELLE: Phys. Rev. Lett. 94: 182002, 2005

Dominantly cc

BELLE

Is it the same as X(3940) ?

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A Broad Structure in J/π+π- Mass near 4.26 GeVe+e- ISRJ/+- in Initial State Radiation

BABAR: 211 fb-1 (preliminary)

(2S)125±23 excess events

Recoil Mass Consistent with zero

hep-ex/0506081, submitted to PRL

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•In addition to (2S) a Broad Structure is Observed in ISR Events

•JPC = 1-- ; Can be Characterized by a single Resonance at 4.26 GeV and Width ~ 0.09 GeV

•Too low Statistics to Discern if Multiple States together - (e.g. S and D waves can mix)

+ - mass distribution from Y(4260)

Y(4260) J/ S-wave phase space

Why no rise in R ?

4.26

D*D* threshold

3.77

BES, PRL 88 (2003), 101802

BABAR

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Pentaquark searchesPentaquark discovery in 2003, ( confirmed by 13 experiments)

(statistical significance of individual experiments is not high ~5-6 )Also many negative searches reported, especially a recent high statistics study by CLAS

Claims of exotic narrow baryons

LEPS, CLAS, …:

M=(1542±5)MeV/c2

<21MeV/c2

NA49:

M=(1862±2)MeV/c2

<18MeV/c2

H1:

M=(3099±6)MeV/c2

<28MeV/c2

S

I3

5(1540)+ [uudds]

5(1860)[ddssu]

5c(3100)[uuddc]

The anti-decuplet for Pentaquarks

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Inclusive and Exclusive Searches at BABAR

5+, 5

--, 50, 5c

0

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accepted by PRL

e+e- annihilation (~123 fb -1)hep-ex/0502004

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accepted by PRL

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Upper Limit

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No Signal Observed by CLAS in this Mode with ~40 times Statistics , now repeating other modes

BABAR studies electro- and hadro-production in interactions with the

material of the inner detector ; Observes no signal

•So far, evidence of 5 claimed in— real/virtual photoproduction— hadroproduction

• photoproduction

36Detector Tomography with pKS0 vertices

230 fb -1BABAR

e- e+

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pKs mass distribution

Mass resolution ~2 MeV

Clear Ks from Decays Selected

Protons Selected from Particle ID

BABAR

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Associate p Ks Vertex with ± and K±

BABAR

(1115)

39No Pentaquark Observed by BABARBABAR

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Charmed Baryon Studies

Precision Mass Measurement of C+ (cud)

Production Process and Ratio of Branching Fractions of C0 (csd)

cc or B C0 + X

Production Process and Ratio of Branching Fractions of C0 (css)

cc or B C0 + X C

0 - +

- + - +

-K- + +

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Mass Measurement of C

+

Using Low-Q-value Decay Modes of C+ KSK+ and C

+ 0KSK+

m(C+ KsK+ ) = 2286.501 ± 0.042 (stat.) ± 0.144 (sys.) MeV/c2

m(C+ 0KsK+ ) = 2286.303 ± 0.181 (stat.) ± 0.126 (sys.) MeV/c2

BABAR Result : m(C+ ) = 2286.46 ± 0.14 MeV/c2

PDG Value 2284.9 ± 0.6 MeV/c2

Cross-checks:

m(C+ pK+ ) = 2286.39 ± 0.12 (stat.) ± 0.45 (sys.) MeV/c2

m(C+ pKs) = 2286.36 ± 0.03 (stat.) ± 0.43 (sys.) MeV/c2

m() = 1115.68 ± 0.01 (stat.) ± 0.04 (sys.) MeV/c2 PDG Value = 1115.683 ± 0.006 MeV/c2 m(KS) = 497.56 ± 0.04 (stat.) ± 0.26 (sys.) MeV/c2 PDG Value = 497.648 ± 0.022 MeV/c2

BABAR

hep-ex/0507009, submitted to PRD

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116 fb -1

c0-π+

c0-K+

B(c0-K+)

B(c0-π+)

= 0.294 ± 0.018 ± 0.016

Goals: Measure Ratio of Decay BFs

: Study Production MechanismBABAR

hep-ex/0504014, submitted to PRL

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Study c0 Momentum (p*) in e+e- rest frame

c0 from B Decays

c0 peak from B’s absent in off-peak

B (B c0X) •B (c

0 -+) = 2.11 ± 0.19(stat.) ± 0.25(syst.) X 10 -

4

c0-π+

(e+e- C0X) •B (c

0 -+) = 388 ± 39(stat.) ± 41(syst.) fb

Results:

Efficiency Corrected

BABAR

116 fb -1

hep-ex/0504014, submitted to PRL

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Inclusive c0 Studies

Branching Fractions and Production Mechanism from p* Spectrum

Decay Modes of C0 Studied -+, -+- +, and -K- + +

C0-+

P* > 2.8 GeV/c

225 fb -1

Results:

BABAR

SLAC-PUB-11323, hep-ex/0507011

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The p* Spectrum from -π+ Mode

Off-peak onlyOn & Off-peak

Not Corrected for Efficiency

B C0 Production (First Observation)

Analysis in Progress

BABAR

SLAC-PUB-11323 hep-ex/0507011

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Summary & Conclusion

Unfolding cs spectroscopy

New States X(3872), Y(3940)… and Y(4260)?

Copious Double Charmonium Production

Pentaquark Fading ?

Exciting Charmed Baryon Spectroscopy

What can we Provide ?

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Kaon momentum spectrum

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Kinematics

DsJ* (2317)

Ds*

reflection

DsJ* (2317)

DsJ (2460) Ds*(Ds

) 0

DsJ* (2317)

reflection

• Mutual cross feed

•widths are consistentwith zero

• No evidence for

DsJ* (2317) DsJ (2460)

DsJ* (2317)

DsJ* (2317) and DsJ (2460)

DsJ (2460) Ds

0

B(DsJ (2460) Ds

0)

B(DsJ (2460) Ds

* 0) 0.21 (90% CL)

B(DsJ (2460) Ds

0)

B(DsJ (2460) Ds

0) 0.11 (95% CL)

Belle 87 fb-1

BaBar 125 fb-1

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DsJ(2460): 0± excluded

Search for DsJ→Ds

DsJ (2460)

B(DsJ (2460) Ds)

B(DsJ (2460) Ds 0)

0.3750.0540.057

B(DsJ (2317) Ds)

B(DsJ (2317) Ds 0)

0.17 (95% CL)

BaBar 125 fb-1

B(DsJ (2460) Ds)

B(DsJ (2460) Ds* 0)

0.550.130.08

B(DsJ (2317) Ds)

B(DsJ (2317) Ds 0)

0.05 (90% CL)

Belle 87 fb-1

Excludes 0± if present

DsJ(2317): compatiblewith 0+

BABAR: PRD 69 (2004) 031101 (R) ; BELLE : PRL 92 (2004) 012002

BABAR

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Search in Inclusive B XK Reconstruction

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Branching fractions from b xk study

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Ds+Results

• D* and selection analogous to inclusive analysis• Ds

+(K+K)fully reconstructed• measure branching fraction product:

Signal 212 ±19

2*4/ BES psm Dividing by our measurement of

B(B0 Ds*+D*-), we obtain

B(Ds++) = (3.6 ± 0.9)% (CLEO)

to be compared with

Readjustment of many results needed!Not used yet for other results in this talk

B (B0 Ds*+ D*) x B (Ds

++) = (8.71 0.78(stat)) x10-4

B(Ds++) = (4.71 ± 0.47(stat) ±0.35(syst))%

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Electroproduction in e-Be

BABAR