Exotic states with cc Riccardo Faccini University “La Sapienza” and INFN Rome FPCP May 2009 Lake Placid, NY, USA

Quarkonium for Pedestrians Quarkonium is a bound state of a quark and an antiquark Quarkonium is a bound state of a quark and an antiquark Relevant quantum numbers: n,L,S,J Relevant quantum numbers: n,L,S,J Relationship with Parity and Charge Conj: Relationship with Parity and Charge Conj: P=(-1) L+1, C=(-1) L+S P=(-1) L+1, C=(-1) L+S Not all J PC allowed (e.g. 0 +-,0 --,1 -+,2 +- forbidden) Not all J PC allowed (e.g. 0 +-,0 --,1 -+,2 +- forbidden) : Decay Properties: Below open quark threshold (e.g. (cc)  DD) only electromagnetic or  s suppressed decays allowed  mostly narrow states Below open quark threshold (e.g. (cc)  DD) only electromagnetic or  s suppressed decays allowed  mostly narrow states Above open quark threshold (if DD decays allowed)  mostly broad states Above open quark threshold (if DD decays allowed)  mostly broad states 2

Charmonium: state of the art M(MeV) J PC (2S+1) L J Increasing L  Increasing n  cc ’c’c J/  ’’  c2  c1  c0 hchc Open charm thr. Basically all states below the open charm threshold are observed and explained same J PC as J/  but mostly D wave !  (3770)  (4040)  (4160) (pot. Models) QWG: hep-ph/

Beyond the quarkonium Search for states with 2 quarks+”something else” Search for states with 2 quarks+”something else” New forms of aggregation New forms of aggregation Expected but never identified!!! Expected but never identified!!! Hybrids: qq+n gluons Hybrids: qq+n gluons Lowest state 1 -+ (forbidden for quarkonium) Lowest state 1 -+ (forbidden for quarkonium) Dominant decay H  DD ** Dominant decay H  DD ** Tetraquarks: [qq’][qq’] Tetraquarks: [qq’][qq’] Large amount of states Large amount of states small widths also above threshold small widths also above threshold Molecules: M[qq]M[q’q’] Molecules: M[qq]M[q’q’] Smaller number of states but still small widths also above threshold Smaller number of states but still small widths also above threshold Search for resonances: with non-quarkonium J PC unnaturally small widths not null charge: would be clear indication of something new going on 4

Measuring the quantum numbers Production: Production: ISR only produces with same quantum numbers as the photon (J PC =1 -- ) ISR only produces with same quantum numbers as the photon (J PC =1 -- )  only produces with C=+  only produces with C=+ Double charmonium production Double charmonium production e + e -   *  X cc 1 X cc 2 Possible only if quantum numbers of the two charmonia can be combined to give a Decay: Decay: Angular distributions of decay products depend on J P. Angular distributions of decay products depend on J P. Selection rules Selection rules Conservation of J Conservation of J Conservation of P,C in strong and electromagnetic decays Conservation of P,C in strong and electromagnetic decays  ISR e+e+ e-e- e-e- e+e+ X e-e- e+e+ X 5

The new zoology X(3872) X(3872) The 1-- family The 1-- family The charged states The charged states hot off the press hot off the press

X(3872): known facts Decays Decays X  J/  (original observation) X  J/  (original observation) Maybe J/  Maybe J/  BF(X  J/  BF(X  J/  BF(X  J/  BF(X  J/  Full angular analysis from CDF Full angular analysis from CDF X  J/  X  J/ Implications: C(X)=+1 C(X)=+1 C(  in J/  decay)=-1 C(  in J/  decay)=-1 I(  )=L(  )=1  consistent with J/  decay hypothesis I(  )=L(  )=1  consistent with J/  decay hypothesis J PC =1 ++ or 2 -+ from angular analysis J PC =1 ++ or 2 -+ from angular analysis Production Production only B decays so far only B decays so far No prompt e + e - production observed (BaBar No prompt e + e - production observed (BaBar arXiv: ) 7

The X(3872) puzzle Open options DD* molecule DD* molecule Right above the threshold Right above the threshold favors DD* decay over J/  over J/  (as observed) favors DD* decay over J/  over J/  (as observed) Tetraquark Tetraquark Explains small width Explains small width Predicts a set of 4 states (2 charged and 2 neutral). Predicts a set of 4 states (2 charged and 2 neutral). Finding these states is critical Finding these states is critical M(MeV) J PC (2S+1) L J Increasing L  Increasing n  cc ’c’c J/  ’’  c2  c1  c0 hchc Open charm thr.  (3770)  (4040)  (4160) (pot. Models) X(3872)? Not matching any predicted state! Above DD threshold (allowed): should have large width but it is narrow Charmonium highly suppressed decay into J/  (isospin violation) 8

Are there two X  J/  CDF with largest sample investigates the mass distribution for two resonances closeby CDF with largest sample investigates the mass distribution for two resonances closeby Fitted mass difference as a function of first gaussian fraction  M<3.2 arXiv:

Is the X in B 0 and B + decays the same? B ±  XK ± B 0  XK S Consistent with one state, equally present in decays More in Phys.Rev.D77: ,2008 X  J/  arXiv:

X(3872)  D 0 D *0 Belle [] observed X(3872)  D 0 D 0  0 Belle [ PRL 97, (2006) ] observed X(3872)  D 0 D 0  0 Confirmation and integration from BaBar in B  DD * K[PRD 77, (2008)] Confirmation and integration from BaBar in B  DD * K[PRD 77, (2008)] Most recent result from Belle Most recent result from Belle D*D0D*D0 D*D0D*D0 11 arXiv:

X(3872) mass Poor agreement among mass measurements: X  J/  and X  DD (*) differ by ~3.5  TWO STATES? X(3872) & X(3876) ? Predicted by tetraquark model (but why so close to threshold?) [my extrapolation] 12

The new zoology X(3872) X(3872) The 1-- family The 1-- family The charged states The charged states hot off the press hot off the press

The 1 -- family Several resonances observed in e + e -  Y  ISR (certainly J PC =1 -- ) Y(4260)  J/  A new state: Y(4260) PRL 95, (2005) Confirmation + J/  0  0 : CLEO PRD74, (2006) CLEO-c PRL 96, (2006) Yet another state Y(4350) PRL 98, (2007) Y(4350)   S  14

The youngest of the 1 -- family 5.8  Y   S  Zoomed BaBar PRL99, (2007) Present in low stat in BaBar’s publication 15

Y(4350) Y(4660) f 0 dominating? Threshold effects? Y(4260) DECAY PROPERTIES arXiv PRL99, (2007)

X(4630) [or Y(4660)?]   c  c Y(4660) good candidate for a  c  c bound state Y(4660) good candidate for a  c  c bound state Search for ISR e + e -   c  c  events Search for ISR e + e -   c  c  events Right sign p Wrong sign p CFR In the discovery mode Assuming same state as  (2S)  ! 17 PRL101, (2008)

ISR search for Y(4260) → D (*) D (*) 18 D D*DD*D D*D*D*D* ψ(3770) ψ(4040) G(3942) ψ(4160) ψ(4415) ψ(4260) Y(4260) is 1 -- charmonium state  should decay predominantly to D D, D * D, and D * D * B A B AR : PRD 79, (2009), 384 D D*DD*D D*D*D*D* ψ(3770) ψ(4040) G(3942) ψ(4160) ψ(4415) ψ(4260)

1 -- family: recap Not matching any potential model prediction Not matching any potential model prediction Too narrow Too narrow M(MeV) J PC (2S+1) L J J/  ’’ Open charm thr.  (3770)  (4040)  (4160) (pot. Models) Only seen in  (2S)  1 -- “new physics”? 4260 can be fit by a tetraquark model (decaying into J/  f 0 …) or a hybrid (with g   ) 19

The new zoology X(3872) X(3872) The 1-- family The 1-- family The charged states The charged states hot off the press hot off the press

The Z(4430) + Charged states a strong prediction of the tetra-quark model Charged states a strong prediction of the tetra-quark model First observed by Belle in PRL100, (2008) First observed by Belle in PRL100, (2008) Search for Z ±  Search for Z ±  J/  or  (2S) +  ± In B     decays M=4433±4±2 MeV  = MeV 121±30 evts, 6.5  21

Criticisms to “discovery analysis” Only “global” Only “global” efficiency efficiencycorrection Poor Poor treatment of 3-body decays (cut away dominant resonances – no interference/reflections) Arbitrary choice of background shape Arbitrary choice of background shape VETOES 22

BaBar Analysis Event-by-event efficiency correction Event-by-event efficiency correction Describe the K  system in detail Describe the K  system in detail Mass Mass Angular distributions fitted with Legendre Polynomials Angular distributions fitted with Legendre Polynomials 23 arXiv:

Comparison of BaBar background with data Same “veto” definition as Belle 24

BaBar results Fitting without vetoes Fitting without vetoes m=4476±8 MeV/c 2 ; Γ=32±16 MeV; signal size: 2.7σ [offset of 43±9 MeV w.r.t. Belle] Same vetoes as Belle Same vetoes as Belle m=4439±8 MeV/c 2 ; Γ=41±33 MeV; signal size 1.9σ m=4439±8 MeV/c 2 ; Γ=41±33 MeV; signal size 1.9σ Conclusions: mistreatement of background might enhance significance veto might bias signal mass measurement 25

Belle Dalitz Plot Analysis Belle’s observation confirmed, but errors increase Belle’s observation confirmed, but errors increase Including  (2S)W Including  (2S)W arXiv: m= MeV Γ= MeV W= CFR. BaBar excludes

Z 1 and Z 2   c1  Same analysis strategy b+d 27 PRD 78, (2008)

Summary of charged states M(MeV) (2S+1) L J J PC Open charm thr.  (3770)  (4040)  (4160) (pot. Models) cc ’c’c J/  ’’  c2  c1  c0 hchc  (4415) The 1 – family Z(4430) Z(4050) Z(4250) 28

The new zoology X(3872) X(3872) The 1-- family The 1-- family The charged states The charged states hot off the press!! hot off the press!!

The 3940 family Observed in J PC M (MeV)  (MeV) X e + e -  J/  X (X  DD * ) 0 -+, ±8<39 Y B  YK (Y  J/  0 ++,1 -+,… 3943±17 [Belle] 3915±4 [BaBar] 87±3436±10 Z   Z (Z  DD) ±529±10 Z  DD Y  J/  X  DD* PRL 96, (2006) PRL 94, (2005) PRL 98, (2007) PRL 101, (2008) 30

New Belle peak in    J/  M: 3914  3  2 MeV,  : 23  MeV, N res = 55  events Signif. = 7.7  31 Preliminary

The 4 states near 3940 X(3940) Y(3940) Belle Z(3930) Mass(GeV) This X(3915) Width(GeV) Range:  (  (stat.)+  (sys.)) Good overlap with BaBar “Y(3940)” values Would allow only the 0++ assignment Better analysis of the J/  mass spectrum needed!! 32

Y(4140) from CDF  M=m(  +  - K + K - )-m(  +  - ) M:  2.9  1.2 MeV,  : ± 3.7MeV, Signif. > 3.8  arXiv: Search for B  YK Y  J/  14  5 events Possible J PC =0 ++,1 -+,2 ++ Another ‘edge’ state, better candidate molecule 33 Lowest lying hybrid, expected at m~4200MeV

Summary M(MeV) J PC (2S+1) L J Open charm thr.  (3770)  (4040)  (4160) (pot. Models) cc ’c’c J/  ’’  c2  c1  c0 hchc X ZY X(3872) never ending story  (4415) More on the family One more member of the 3940 family X(4160) Z(4430) Z(4050) Z(4250) The charged candidates 34 y (4140) New state from CDF Good Hybrid candidate

Outlook Plenty of states seen with low stat and in only one channel  next generation [SuperB(elle)?] needed J/     D (*) D (*) J/  J/      (2S)  J/  K,   S  J/  J/  X(3872)SeenSeen Not seen No search N/A Not seen Seen Y(3940) No Fit X(3940 )? Seen No search Not seen No search No Fit No fit Y(4260)Seen Not Seen No fit No search Not seen No fit N/A Y(4350) Not seen No fit No search Seen No fit N/A Z(4430) No search No fit No search Seen Not Seen No search No Fit N/A Y(4660) Not seen No fit No search Seen No Fit N/A 35

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Confirmation of Y(3940) (B  K  J/  +-0+-0 B   YK  B 0  YK S B0/BB0/B Isospin cons. 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   Preliminary BF estimate similar to Belle’s (~10 -5 ) preliminary G. Cibinetto, talk at this conference M(J/  ) (GeV) Y(3940) closer to X(3940) Can they be the same state? 37

D D*D*D* D D* X(4160)  D * D * e + e -  J/  D (*) D (*) Obtain J/  D (*) D (*) samples through kinematic separation, look at m(D(*)D(*)) after background subtraction: M = 3942 ±6 MeV  tot =37 ±12 MeV N ev = 52 ±11 Inferred (Recoil mass) X(4160) claim: new state M = 4156 ±15MeV  tot = 37 ±21MeV N ev =  3.8  X(3940)Cross-check X(3940) is still there, 6.0  Something’s here, but it’s not X(3940) M(DD) M(D*D*) M(DD*) M(D * D) J/  D+ J/  D*+ Number of events One more particle to explain … J CP =0 -+ not excluded (  c (3S)) reconstructed BELLE-CONF

“Just” charmonium states? M(MeV) J PC (2S+1) L J Open charm thr.  (3770)  c1 (pot. Models)  c2  c0 ’c’c cc X ZY=X(3915) Poor match with predictions Poor match with predictions Above threshold? Above threshold? If X≠Y, difficult to explain absence of Y  open charm If X≠Y, difficult to explain absence of Y  open charm Hybrid? Hybrid? 39

Fits to J/  KK invariant mass ‘Standard ‘ y(4415) + 1 BW: M = (4875±132) MeV  = (630±126) MeV single BW: M = (4430±38) MeV  = (254±49) MeV 40

Thresholds and new states X(3872) Y(4260) X(4160) XYZ(3940) Y(4350) Y(4660) 41

CLEO and Belle on

Search for X(3872)  J/  in continuum X>2 ch  c production is consistent with the expected contributions from prompt  (2S) production feed-down to  c : no evidence of prompt  c1,2 No evidence of X(3872) production in e + e - annihilation.  c1,2 or X(3872)  c1  c2 X(3872) 386fb -1 J/  production observed in continuum while no evidence of  c states. arXiv:

Experiments e + e -  Charmonium (CLEO-c, BES-II) e + e -  Charmonium (CLEO-c, BES-II) L~10 33 /cm 2 /s L~10 33 /cm 2 /s E= GeV E= GeV e + e -  Y(4S): (BaBar, Belle, CLEO) e + e -  Y(4S): (BaBar, Belle, CLEO) L~10 34 /cm 2 /s L~10 34 /cm 2 /s Charmonium in B decays, ISR and  production Charmonium in B decays, ISR and  production Capability to measure J PC also in production Capability to measure J PC also in production pp colliders (CDF, D0) pp colliders (CDF, D0) High Xsection  copious production High Xsection  copious production Extremely high backgrounds Extremely high backgrounds 3M  (2S), 1.8 M  (3770) 58MJ/ , 14M  (2S) 383M Y(4S) 657M Y(4S) 1.5M Y(1S),1.9M Y(2S),1.7M Y(3S),9M Y(4S) Samples used in results 2.4bf fb -1 Disclamers: time is very short  could not cover everything theory statements are indicative 44