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 X(3872) propertiesX(3872) properties Y(3940), a hybrid state? Y(3940), a hybrid state? X(3940), a new charmonium state? X(3940), a new charmonium state? Z(3930), an excited charmonium state?Z(3930), an excited charmonium state? SummarySummary

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

M= 3872.0 ± 0.6 ± 0.5 MeVM= 3872.0 ± 0.6 ± 0.5 MeV <2.3 MeV @90% C.L.<2.3 MeV @90% C.L.

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 experiments (BaBar, D0, CDF) and included in PDG2005Confirmed by other experiments (BaBar, D0, CDF) and 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 charmonium states do not fit well any potential model charmonium states M(M(++--) peaks at kinematic limit () peaks at kinematic limit ((770)-like) (770)-like) X(3872) X(3872) 00J/J/ is isospin violating decay is isospin violating decay MMXX ~ M ~ MD*D*00+ + MMDD0 0 speculation that X might be a molecular D* speculation that X might be a molecular D*00DD00 bound bound statestate

JJPCPC= 1= 1++ ++ favored by some models (Sfavored by some models (Swanson, PLB 588, 189(2004)wanson, PLB 588, 189(2004))) Expected admixture of Expected admixture of (782)J/(782)J/ and a small and a small (770)J/(770)J/ component component in addition to D*in addition to D*00DD00


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 BK X(3872), X(3872) K X(3872), X(3872) J/J/ decay decay MMbcbc distributions in M( distributions in M( J/J/) bins ) bins significant B signal only for M(significant B signal only for 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 versus M( signal yield versus M( J/J/) )

BFBF(B(BK X)K X)BFBF(X(X J/J/)=1.8±0.6±0.1)=1.8±0.6±0.11010-6-6

(X(X J/J/))//(X(X++--J/J/) = 0.14±0.05) = 0.14±0.05

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/))


X(3872) X(3872) J/J/ sub-threshold decay sub-threshold decay Kinematical limit for X(3872) Kinematical limit for X(3872) J/J/ is 7.5MeV below M is 7.5MeV below M via virtual via virtual Search for BSearch for BK X(3872), X(3872) K X(3872), X(3872) J/J/, , ++--0 0 decaydecay BBK K ++--0 0 J/J/ candidates selected in candidates selected in E-ME-Mbc bc signal region signal region X(3872) X(3872) ++--0 0 J/J/ selected:|M(3 selected:|M(3J/J/) – 3872|<16.5 MeV) – 3872|<16.5 MeV MMbcbcvs. vs. E distributions fitted in bins of M(E distributions fitted in bins of M(++--0 0 ) ) B signal yield versus M(B signal yield versus M(++--0 0 ) ) Significant B signal only for Significant B signal only for (782) region M((782) region M(++--0 0 )>750 MeV )>750 MeV Background: 2.1±1.0 (from BBackground: 2.1±1.0 (from BK K J/J/ and non-resonant B and non-resonant BK K ++--0 0 J/J/))

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 large isospin violation!violation!

Strong support for molecular D*Strong support for molecular D*00DD00 interptetationinterptetation Further evidence of C=+1 for Further evidence of C=+1 for X(3872)X(3872)

Virtual Virtual (782)?(782)?N=12.4±4.1 (4.3N=12.4±4.1 (4.3) )

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

Constraints on JConstraints on JPC PC of X(3872) Iof X(3872) I Fit to M(Fit to M(++--) ) For C=+1 states For C=+1 states ++- - J/J/ final state is primarily final state is primarily J/J/, , JJ++ ++ : : and J/ and J/ in a relative S/D-wave; J in a relative S/D-wave; J--+ + : : and J/ and J/ in a P-wave in a P-wave M(M(++--) at kinematical limit is suppressed by (p*) at kinematical limit is suppressed by (p* J/J/))2L+1 2L+1

shape of high-mass part of M(shape of high-mass part of M(++--) provides some J) provides some JPC PC informationinformation


PPX(3872)X(3872) =+1 is favored =+1 is favored

X(3872)X(3872) D D00DD000 0 observationobservation BBKK DD00DD0000 (K(K DD00 D* D*00)) candidates selectedcandidates selected using using E-ME-Mbc bc Enhancement in M(DEnhancement in M(D00DD0000))MMXX observed observed It is difficult to distinguish DIt is difficult to distinguish D00DD0000 andand DD00 D* D*00BFBF(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 by M(Favored by M(++--))P-waveP-wave

2/d.o.f=71/392/d.o.f=71/39DisfavoredDisfavored

M(M(++--)) PreliminaryPreliminary

N=12.5±3.9 N=12.5±3.9 (>5(>5) )

XXDDDD makes J makes J2 unlikely, 2 unlikely, for J=2 D-wave required, suppressed by (p*)for J=2 D-wave required, suppressed by (p*)55


Constraints on JConstraints on JPC PC of X(3872) IIof X(3872) II Two-body decay BTwo-body decay BKX(3872) KX(3872) constraints on X spin and K-X relative angular momentumconstraints on X spin and K-X relative angular momentum Full angular analysis limited by low statistic (NFull angular analysis limited by low statistic (NXX50 events)50 events) Rosner’s coordinate system:Rosner’s coordinate system: x-axis is negative of K direction in X rest x-axis is negative of K direction in X rest frame, x-y plane defined by frame, x-y plane defined by ++ and K, z-axis completes and K, z-axis completes right handed systemright handed system Rosner PRD 70, 094023 Rosner PRD 70, 094023 (2004)(2004) Each JEach JPCPC hypothesis is examined using most distinctive angular hypothesis is examined using most distinctive angular distributiondistribution

00--+ + hypothesis:hypothesis: and J/ and J/ in a P-wave in a P-wave Predicted angular distribution: dPredicted angular distribution: d22N/d(cosN/d(cos) d(cos) d(cos) ) sin sin22 sin sin22 (in the limit where X, (in the limit where X, and J/ and J/ rest frames coincide) rest frames coincide)

Poor 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||

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||

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


00++ ++ hypothesis: hypothesis: and J/ and J/ in relative S- or D-wave in relative S- or D-wave (D-wave disfavored by M((D-wave disfavored by M(++--) and suppressed by phase space) ) and suppressed by phase space) Predicted angular distribution: dN/d(cosPredicted angular distribution: dN/d(cosll)) sin sin22ll

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

2/d.o.f=31/92/d.o.f=31/9MC MC expectationexpectation

|cos|cosll||

Poor agreement Poor agreement

00++ ++ ruled outruled out

Good agreement Good agreement for both distr.for both distr.

11++ ++ favoredfavored

Discovery of X(3872) encouraged further studies of Discovery of X(3872) encouraged further studies of hh+J/+J/ systems systems BBK K J/ J/, , ++--0 0 candidates selectedcandidates selected B signal yield determine in M(B signal yield determine in M(J/J/) bins ) bins by performing fits to Mby performing fits to Mbcbc distributions distributionsStrong near-threshold enhancement in M(Strong near-threshold enhancement in M(J/J/) @ 3.94GeV) @ 3.94GeV

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

Is Y(3940) threshold effect or new charmonium state? Is Y(3940) threshold effect or new charmonium state? Charmonium meson with this mass would dominantly decay to DDCharmonium meson with this mass would dominantly decay to DD ((**))

Y(3940) properties are similar to those predicted Y(3940) properties are similar to those predicted for some of the cc-gluon hybrid statesfor some of the cc-gluon hybrid statesJolanta BrodzickaJolanta Brodzicka, , INP Kraków New Resonances ICFP 2005INP Kraków New Resonances ICFP 2005

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


Observation of X(3940) in eObservation of X(3940) in e++ee--J/J/ X annihilation X annihilation Double charmonium production in e+e- annihilation (J/Double charmonium production in e+e- annihilation (J/ + + cc cc ’’cc): ): large cross sections, difficult to understand within NRQCDlarge cross sections, difficult to understand within NRQCD cc production in different processes not completely understood cc production in different processes not completely understood theoretical interest renewedtheoretical interest renewed Searching region extended above DD threshold with new data (350fbSearching region extended above DD threshold with new data (350fb -1-1)) Spectrum of a J/Spectrum of a J/ recoil mass studied recoil mass studied

New peak observed in MNew peak observed in Mrecoilrecoil(J/(J/) @ 3.94GeV) @ 3.94GeV =39±29MeV=39±29MeV

2/

*2/

* )()/( JJCMSrecoil pEEJM

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

cc cc’’cc

DD thresholdDD thresholdBornBornBFBF( X(3940)( X(3940)>2 charged tracks )>2 charged tracks ) =10.6±2.5±2.4 fb =10.6±2.5±2.4 fb


Search for X(3940) Search for X(3940) DD((**))D D Full reconstruction of eFull reconstruction of e++ee-- J/J/X, XX, XDD((**))D not practical D not practical To increase efficiency only one D reconstructedTo increase efficiency only one D reconstructed Spectrum of MSpectrum of Mrecoilrecoil(J/(J/D) is studied, D) is studied, other Dother D((**) ) seen as peak in Mseen as peak in Mrecoilrecoil(J/(J/D) D) (D* and D well separated)(D* and D well separated) Observed processes eObserved processes e++ee-- J/J/DD, J/DD, J/DD*DD* MMrecoilrecoil(J/(J/D) refited to MD) refited to MDD or M or MD*D* to improve Mto improve Mrecoilrecoil(J/(J/) resolution ) resolution Search for XSearch for XDD((**))D in MD in Mrecoilrecoil(J/(J/) ) M(DM(D((**))D) D) spectraspectra

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 ± 10 MeV=15.4 ± 10 MeV

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

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

––3.53.5

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

BFBF(X(3940)(X(3940)D*D) = 96 D*D) = 96 +45 +45 ±22 % ±22 % dominant decay modedominant decay mode -32-32


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 from e reconstructed from e++ee-- J/J/ J/ J/ final state final stateM(J/M(J/ ) vs. M) vs. Mrecoilrecoil(J/(J/ ) studied to look for X(3940)) studied to look for X(3940)

forforMM (J/(J/ ) – M) – MX(3940)X(3940)< 40 MeV < 40 MeV

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

Signal region for Signal region for ee++ee-- J/J/ X(3940), X(3940), X(3940) X(3940) J/ J/

NNJ/J/= 2.2 = 2.2 +4.5+4.5––3.73.7

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


Motivation: study Motivation: study production of high mass cc states decaying production of high mass cc states decaying into DDinto DD Known radially excited 2S charmonium states Known radially excited 2S charmonium states ’ and ’ and ’’cc: M<M: M<MDDDD

2233PPJJ((’’ccJJ) predicted to lie: 3.9-4.0 GeV) predicted to lie: 3.9-4.0 GeV and to decay mainly to DD and to decay mainly to DD

Search for cc statesSearch for cc states produced via produced via DD process DD process by studying untagged mode eby studying untagged mode e++ee-- ee++ee-- DD DD PPtt(DD)<0.05GeV in(DD)<0.05GeV in ee++ee-- cms cms it restricts it restricts virtualities virtualities and enhances exclusive and enhances exclusive DD production DD production New peak observed in M(DD)@ 3.93 GeV New peak observed in M(DD)@ 3.93 GeV PPtt(DD) distribution for Z(3930) region agrees with (DD) distribution for Z(3930) region agrees with MC for exclusive two-photon DD production MC for exclusive two-photon DD production 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

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


Z(3930) angular distributionZ(3930) angular distribution

for 3.91< M(DD) <3.95 GeV/cfor 3.91< M(DD) <3.95 GeV/c22

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 a J=2 assignment Data prefer a J=2 assignment Z(3930) is Z(3930) is ’’cc22 the 2 the 233PP2 2

charmonium statecharmonium state

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


SummarySummary

Belle found:Belle found: More informations to explain X(3872) propertiesMore informations to explain X(3872) properties X(3872) quantum numbers: JX(3872) quantum numbers: JPCPC=1=1++++ New charmonium state X(3940) (New charmonium state X(3940) (cc(3S)?) (3S)?) in double charmonium productionin double charmonium production Z(3930) in Z(3930) in process, Z(3930) = process, Z(3930) = ’’c2 c2

new resonances at belle jolanta brodzicka inp kraków, for the belle collaboration icfp 2005

Documents

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x3872 j c

summary x3872 j

j cx3872

j bins bk j signal yield

jbf x j

bk x3872

studies of h j systems