New Resonances at Belle Jolanta Brodzicka INP Kraków, for the Belle Collaboration ICFP 2005

New Resonances at BelleNew Resonances at Belle

Jolanta Brodzicka INP Kraków, Jolanta Brodzicka INP Kraków, for the Belle Collaborationfor the Belle Collaboration

ICFP 2005ICFP 2005October 4October 4thth, 2005 Taiwan , 2005 Taiwan

Outline Outline ‘ ‘old’ X(3872) properties (in Bold’ X(3872) properties (in BK X)K X) Y(3940) in Y(3940) in BBK K J/ J/ X(3940) in double charm productionX(3940) in double charm production Z(3930) inZ(3930) in γγγγ productionproduction SummarySummary

X(3872)X(3872)++- - J/J/ discovered by Belle in 2003 in B discovered by Belle in 2003 in B++KK++++- - J/J/

M= 3872.0 ± 0.6 ± 0.5 MeV M= 3872.0 ± 0.6 ± 0.5 MeV ~ M ~ MD*D*0 0 + M+ MDD00

<2.3 MeV @90% C.L. <2.3 MeV @90% C.L. narrow narrow

BFBF(B(BK X)K X)BFBF(X(X++--J/J/)=1.31±0.24±0.13 )=1.31±0.24±0.13 1010-5 -5

Confirmed by other exp. (D0, CDF, BaBar), included in PDG2005Confirmed by other exp. (D0, CDF, BaBar), included in PDG2005

Jolanta BrodzickaJolanta Brodzicka, , INP Kraków New Resonances ICFP 2005INP Kraków New Resonances ICFP 2005

Intriguing X(3872)Intriguing X(3872)

253fb253fb-1-1

N=49.1N=49.18.48.4 XX++- - J/J/

M(M(++--J/J/))

M and M and do not fit well any potential model cc states do not fit well any potential model cc states

Speculations: X is a D*Speculations: X is a D*00DD00 bound state bound state (predicted by Tornqvist (predicted by Tornqvist 1994)1994)

JJPCPC= 1= 1++ ++ favored by some models favored by some models (Swanson, PLB 588, (Swanson, PLB 588, 189(2004))189(2004)) expected admixture of expected admixture of (782)J/(782)J/ and and (770)J/(770)J/ components, components, in addition to D*in addition to D*00DD00 (isospin viol. decays) (isospin viol. decays)

PRL 91, 262001PRL 91, 262001


Evidence for X(3872) Evidence for X(3872) J/J/

If X(3872) If X(3872) J/J/ C=+1 for X(3872) C=+1 for X(3872) search for Bsearch for BKKXX, , XXJ/J/ MMbcbc distributions in M( distributions in M(J/J/) bins ) bins BBKK J/J/ signal signal seen seen only for only for M(M(J/J/)~M)~MX(3872)X(3872)

Fit MFit Mbcbc in M( in M(J/J/) bins ) bins BBK K J/J/ signal yield vs M( signal yield vs M(J/J/) )

BFBF(B(BKX)KX)BFBF(X(XJ/J/)=1.8±0.6±0.1)=1.8±0.6±0.11010-6-6

CCX(3872)X(3872) =+1 established =+1 established

X(3872) regionX(3872) region

N=13.6±4.4 (4.0N=13.6±4.4 (4.0))

M(M(J/J/))

Theory expects: ~40 for Theory expects: ~40 for X(3872)=’c1(23P1)

hep-ex/0505037hep-ex/0505037

(X(XJ/J/))

(X(X++--J/J/))= 0.14±0.05= 0.14±0.05


X(3872) X(3872) J/J/ sub-threshold decay sub-threshold decay

Search for BSearch for BK X(3872), K X(3872),

X(3872)X(3872)J/J/, , ++--0 0

MMbcbcvs. vs. EE fitted in M(fitted in M(++--00) ) binsbins

BBKX,KX, XX++--0 0 J/J/ signal signal

yield vyield vs.s. M( M(++--00) ) Significant B signal only for Significant B signal only for

M(M(++--00)) >750 MeV >750 MeV

Support for molecular Support for molecular D*D*00DD00 interpretation interpretation (Swanson)(Swanson) Further evidence of C=+1 Further evidence of C=+1 for X(3872)for X(3872)

BFBF(X(X ++--0 0 J/J/))BFBF( X( X ++--J/J/))

=1.0 ±0.4 ±0.3 =1.0 ±0.4 ±0.3

large isospin violation!large isospin violation!

Virtual Virtual (782)?(782)?

N=12.4±4.1 (4.3N=12.4±4.1 (4.3) )

M(M(++--0 0 ))

Bkd=2.1Bkd=2.1±±1.01.0

(782)(782)ΓΓ=8.4=8.4MeVMeV

hep-ex/0505037hep-ex/0505037

Constraints on JConstraints on JPC PC of X(3872) Iof X(3872) I

Fit to M(Fit to M(++--) )

if C=+1: if C=+1: ++--J/J/ is primarily is primarily J/J/ JJPCPC(X)= J(X)= J++ ++ : : and J/ and J/ in a S/D-wave in a S/D-wave JJ--+ + : : and J/ and J/ in a P-wave in a P-wave

M(M(++--) at kinematical limit is ) at kinematical limit is

suppressed by (p*suppressed by (p*J/J/))2L+1 2L+1

shape of high-mass part of shape of high-mass part of

M(M(++--) )

provides some Jprovides some JPC PC informationinformation


JJ++++ is favored is favored

X(3872)X(3872) D D00DD000 0 observationobservation BBKK DD00DD0000 /K/K DD00D*D*00 candidates candidates selected using selected using E-ME-Mbc bc

Enhancement in M(DEnhancement in M(D00DD0000))MMXX observed observed Difficult to distinguish DDifficult to distinguish D00DD0000 // DD00D*D*0 0

BFBF(B(BK X)K X)BFBF(X(XDDDD)=1.6±0.4±0.3)=1.6±0.4±0.31010-4-4

S-waveS-wave2/d.o.f=43/392/d.o.f=43/39

favored favored

P-waveP-wave2/d.o.f=71/392/d.o.f=71/39

disfavoreddisfavored

M(M(++--))

N=12.5±3.9 N=12.5±3.9 (>5(>5) )

XXDDDD suggests that J suggests that J2 is unlikely, 2 is unlikely, (at least 1 pair in D-wave, (at least 1 pair in D-wave, suppressed by p* suppressed by p* 55))

Prelim

inary

Prelim

inary

hep-ex/0505038hep-ex/0505038


Constraining JConstraining JPCPC[X(3872)] from angular distr.[X(3872)] from angular distr.

Full angular analysis limited by low statisticsFull angular analysis limited by low statistics ApproximationApproximation for for BBK XK X,, X X J/J/, , ++-- , , J/J/ ll++ll- - : : X, X, and J/ and J/ rest frames rest frames coincide, coincide, angular distr. are predicted in theangular distr. are predicted in the joint ref. frame (joint ref. frame (Rosner PRD 70, 094023 (2004))Rosner PRD 70, 094023 (2004))

Rosner’s coordinate system:Rosner’s coordinate system: x-axis is negative of K direction in X rest frame,x-axis is negative of K direction in X rest frame,

x-y plane defined by x-y plane defined by ++ and K, z-axis completes and K, z-axis completes right handed systemright handed system Each JEach JPCPC hypothesis examined using hypothesis examined using the most distinctive angular distr.the most distinctive angular distr.

00--+ + hypothesishypothesis

and J/and J/ in a P-wave in a P-wave:: dd22N/d(cosN/d(cos) d(cos) d(cos) ) sin sin22 sin sin22Poor fit to cosPoor fit to cos distribution distribution

evidence against 0evidence against 0--+ +

2/d.o.f=18/92/d.o.f=18/9

2/d.o.f=34/92/d.o.f=34/9

MC MC expectationsexpectations |cos|cos||

|cos|cos||

hep-ex/0505038hep-ex/0505038

Constraints on JConstraints on JPC PC of X(3872)of X(3872)


00++ ++ hypothesis: hypothesis: (( and J/ and J/ in S/D-wave) in S/D-wave)2/d.o.f=31/92/d.o.f=31/9MC MC

expectationexpectation

|cos|cosll|| Poor agreementPoor agreement

00++ ++ ruled ruled outout

Predicted: Predicted:

dN/d(cosdN/d(cosll)) sin sin22ll

11++ ++ hypothesis: hypothesis: (( and J/ and J/ in S/D- in S/D-wave)wave) Predicted: Predicted: dd22N/d(cosN/d(cosll) d(cos) d(cos)) sinsin22ll sin sin22

2/d.o.f=11/92/d.o.f=11/9

2/d.o.f=5/9 2/d.o.f=5/9 |cos|cosll||

|cos|cos||

Good Good agreement agreement

11++ ++ favoredfavored


Observation of Y(3940) Observation of Y(3940) J/ J/

N=58±11 (8.1N=58±11 (8.1))M= 3943±11±13 MeV M= 3943±11±13 MeV =87±22±26 MeV =87±22±26 MeV

BFBF(B(BKY)KY)BFBF(Y(YJ/J/))=7.1 ±1.3 ±3.1=7.1 ±1.3 ±3.11010-5-5

Strong near-threshold enhancement Strong near-threshold enhancement in M(in M(J/J/) @ 3.94GeV) @ 3.94GeV

X(3872) X(3872) ++- - J/J/ encouraged further encouraged further studies of studies of hh+J/+J/ systems: systems:

J/J/ system in B system in BK K J/J/, , ++--0 0

BBKKJ/J/ signal yield determined in signal yield determined in M(M(J/J/) bins by fits to M) bins by fits to Mbcbc distr distr..

threshold effect? new charmonium threshold effect? new charmonium state? state? cc at this mass dominantly cc at this mass dominantly DDDD((**))

cc-g hybrid? (predicted states with cc-g hybrid? (predicted states with properies similar to Y(3940), but properies similar to Y(3940), but M>4GeV)M>4GeV)

PRL 94, 182002PRL 94, 182002


Observation of X(3940) in eObservation of X(3940) in e++ee--J/J/ X X

2/

*2/

* )()/( JJCMSrecoil pEEJM

Fit result:Fit result:X(3940X(3940))

cc cc

’’cc

DD thresholdDD threshold

BornBornBFBF( X(3940)( X(3940)>2 charged tracks )>2 charged tracks ) =10.6±2.5±2.4 fb =10.6±2.5±2.4 fb

(>4 ch.tracks required in analysis and (>4 ch.tracks required in analysis and J/J/llll ))

Recoil mass against J/Recoil mass against J/ studied: studied:

New peak observed in MNew peak observed in Mrecoilrecoil(J/(J/) @ 3.94GeV ) @ 3.94GeV hep-ex/0507019hep-ex/0507019

PRL 89, 142001PRL 89, 142001

Double cc production in e+eDouble cc production in e+e-- annihilation (J/ annihilation (J/ + + cc cc ’’cc): ): large cross sections, difficult to understand by theorylarge cross sections, difficult to understand by theory Searching region extended above DD thr. with new data Searching region extended above DD thr. with new data (350fb(350fb-1-1))

XX < 52MeV @ 90%C.L < 52MeV @ 90%C.L


Search for X(3940) Search for X(3940) DD((**))D D

BFBF>2>2 (X(3940)(X(3940)DD) < 41% @90% C.L.DD) < 41% @90% C.L. (conservative)(conservative)

NNDDDD= 86±17= 86±17NND*DD*D= 55±18= 55±18

BFBF>2>2 (X(3940)(X(3940)D*D) = 96 D*D) = 96 +45 +45 ±22 % ±22 %

seems to be dominant decay modeseems to be dominant decay mode-32-32

MMrecoilrecoil(J/(J/D) is studied: the D) is studied: the other Dother D((**) ) seen as peak in seen as peak in

MMrecoilrecoil(J/(J/D) D) (D* and D signals well (D* and D signals well separated)separated)MMrecoilrecoil(J/(J/D) refited to MD) refited to MDD or M or MD*D* to improve Mto improve Mrecoilrecoil(J/(J/) resolution) resolution

ee++ee-- J/ J/DD, J/DD, J/DD* observedDD* observed

Full reconstruction of eFull reconstruction of e++ee-- J/J/X, XX, XDD((**))D not practical (low D not practical (low eff.) eff.) one D reconstructedone D reconstructed

MMrecoilrecoil(J/(J/) ) M(D*D), M(DD) M(D*D), M(DD) spectra spectra

X(3940)X(3940)DDDDN=0.2 N=0.2 +4.4+4.4 <8.1 <8.1

––3.53.5

X(3940)X(3940)D*DD*DN=24.5 ± 6.9 (5.0N=24.5 ± 6.9 (5.0) ) M=3943 ± 6 MeVM=3943 ± 6 MeV =15.4 ± 10MeV =15.4 ± 10MeV

NNJ/J/= 2.2 = 2.2 +4.5+4.5

––3.73.7


Are X(3940) and Y(3940) the same particle?Are X(3940) and Y(3940) the same particle?

Search for X(3940) Search for X(3940) J/ J/ J/J/ reconstructed in e reconstructed in e++ee-- J/J/ J/ J/ M(M( J/ J/) vs. M) vs. Mrecoilrecoil(( J/ J/) studied to look for X(3940)) studied to look for X(3940)

for for M(M(J/J/) – M) – MXX< 40 MeV< 40 MeV

for for MMrecoilrecoil ( (J/J/) – M) – MJ/J/<100 MeV <100 MeV

Signal region Signal region for efor e++ee--J/J/X, X, XX J/ J/

NNX X = 1.9 = 1.9 +3.2+3.2 < 7.4 @90% C.L. < 7.4 @90% C.L.

BFBF( X(3940)( X(3940)J/J/ ) < 26% @90% C.L.) < 26% @90% C.L.

––2.42.4

X(3940) does not decay X(3940) does not decay into J/into J/


N=41N=4111 (5.511 (5.5))M=3931M=3931442 MeV 2 MeV =20=20883 MeV 3 MeV

MC MC expectationexpectation

(2J+1)(2J+1) BF BF (Z(ZDD) =1.13±0.30±0.18 DD) =1.13±0.30±0.18 keVkeV

Observation of Z(3930) in Observation of Z(3930) in DD DD

hep-ex/0507033hep-ex/0507033 Motivation: study Motivation: study production of high production of high mass mass cc states decaying into DDcc states decaying into DD Known 2S charmonia Known 2S charmonia ’ and ’ and ’’cc: M<M: M<MDDDD

2233PPJJ((’’ccJJ) predicted at ~3.9-4.0 GeV) predicted at ~3.9-4.0 GeV

and to decay mainly to DDand to decay mainly to DD untagged untagged in e in e++ee-- ee++ee-- DD DD PPtt(DD)<0.05GeV in(DD)<0.05GeV in ee++ee-- cms cms enhances exclusive enhances exclusive DD productionDD production

New peak in M(DD)@3.93 GeVNew peak in M(DD)@3.93 GeV PPtt(DD) distr. for Z(3930) (DD) distr. for Z(3930) peak agrees with MC for peak agrees with MC for DD DD

Study of the D angle relative to the beam axis in Study of the D angle relative to the beam axis in cms cms


Z(3930) angular distributionZ(3930) angular distribution

for 3.91< M(DD) <3.95 GeVfor 3.91< M(DD) <3.95 GeV

Spin-2Spin-2 dN/d(cos dN/d(cos *)~sin*)~sin44**

2/d.o.f=7/92/d.o.f=7/9

Spin-0Spin-0flat distr.flat distr.

2/d.o.f=32/92/d.o.f=32/9Data prefer J=2 assignment Data prefer J=2 assignment Z(3930) is Z(3930) is ’’cc22 2233PP2 2 charmonium statecharmonium state

Events from the 3.93 GeVEvents from the 3.93 GeV peak peak tend to concentrate at small |cos tend to concentrate at small |cos **

valuesvalues


SummarySummary

Belle at KEK-B: the goldmine for spectroscopyBelle at KEK-B: the goldmine for spectroscopy This year:This year: new decay modes of X(3872), Jnew decay modes of X(3872), JPCPC=1=1++ ++ established (established (’’c1c1 unlikely) unlikely) new X(3940) in double charm production (new X(3940) in double charm production (cc(3S)?) (3S)?) Z(3930) in Z(3930) in process ( process (’’c2c2 likely) likely)

Earlier observations:Earlier observations: ’’cc(2S) (2S) D** (+DD** (+DsJsJ) ) cc(2800) isotriplet(2800) isotriplet Y(3940) (cc g hybrid?)Y(3940) (cc g hybrid?)

New Resonances at Belle Jolanta Brodzicka INP Kraków, for the Belle Collaboration ICFP 2005

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