Searches for exotic mesons Stephen L. Olsen University of Hawai’i DOE site visit Aug 22, 2005 cc u d u u d u uc u c Multi-quark molecules qq-gluon hybrids baryonium

test of QCD: “running”  s

Probe QCD from other directions non-qq or non-qqq hadron spectroscopies: Reawakened by the claims for Pentaquarks e.g. an S=+1 baryon u d u s d

Pentaquarks? “Seen” in many experiments BaBar High interest: 1 st pentaquark paper has >500 citations Belle BES but not seen in just as many others CDF Compass Jlab p

Pentaquark Scoreboard Positive signals Negative results Also: Belle Compass L3 Jlab(CLAS) (  p  K + K s n) Yes: 17 No: 18

This talk Searches for non-standard mesons with hidden charm at Belle Search for baryonium mesons at BES cc uc u c u d u u d u

searches for non-standard mesons with “hidden charm” at Belle standard cc mesons are: –best understood theoretically –narrow & non overlapping c + c systems are commonly produced in B meson decays. b c c s V cb cos  C CKM favored W-W- cc uc u c (i.e containing c & c)

Thanks to KEKB, Belle has lots of B mesons (>1M BB pairs/day) >1fb -1 /day Design: 10 34

X(3872)      J/  B  K     J/  M(  J  ) –M(J/  )  ’      J/  X(3872)      J/  S.-K.Choi, S.L.Olsen et al (Belle) PRL (2003)

Its existence is well established seen in 4 experiments X(3872) CDF X(3872) D0 hep-ex/  11.6 

Is it a cc meson? These states are already identified 3872 MeV Could it be one of these?

no obvious cc assignment 3872  c ” h c ’  c1 ’  2  c2  3 M too low and  too small angular dist’n rules out 1   J/  way too small  c   too small;M(     ) wrong  c  & DD) too small  c should dominate SLO hep-ex/

go back to square 1 Determine J PC quantum numbers of the X(3872) with minimal assumptions

J PC possibilities (for J ≤ 2) 0 -- exotic violates parity 0 -+ (  c ” ) 0 ++ DD allowed (  c0 ’ ) 0 +- exotic DD allowed DD allowed (  (3S)) 1 -+ exotic DD allowed 1 ++ (  c1 ’ ) 1 +- (h c ’ ) 2- -(2)2- -(2) (  c2 ) 2 ++ DD allowed  c2 ’ ) 2 +- exotic DD allowed

J PC possibilities 0 -- ruled out; J P =0 +,1 - & 2 + unlikely 0 -- exotic violates parity 0 -+ (  c ” ) 0 ++ DD allowed (  c0 ’ ) 0 +- exotic DD allowed DD allowed (  (3S)) 1 -+ exotic DD allowed 1 ++ (  c1 ’ ) 1 +- (h c ’ ) 2- -(2)2- -(2) (  c2 ) 2 ++ DD allowed  c2 ’ ) 2 +- exotic DD allowed

Strong evidence for C= ± 4.4 X(3872)   J/  evts (>4  significance) X(3872)   J/  12.4 ± 4.2 evts12.4 ± 4.2 evts virtual  (782)? X(3872)        J/  Bf(X   J/  ) Bf(X   J/  ) =0.14 ± 0.05 Br(X  3  J/  ) Br(X  2  J/  ) = 1.0 ± 0.5 M(       ) M(     ) X(3872)      J/  Fits to  (760)

J PC possibilities (C=-1 ruled out) 0 -- exotic Violates parity 0 -+ (  c ” ) 0 ++ DD allowed (  c0 ’ ) 0 +- exotic DD allowed DD allowed (  (3S)) 1 -+ exotic DD allowed 1 ++ (  c1 ’ ) 1 +- (h c ’ ) (  2 ) (  c2 ) 2 ++ DD allowed  c2 ’ ) 2 +- exotic DD allowed

Angular Correlations K  J/  J=0 X 3872 J z =0 z Rosner (PRD ) Bugg (PRD ) Suzuki, Pakvasa (PLB )

ll |cos  l  |  2 /dof = 34/9   |cos  | |cos  |  2 /dof=34/9  2 /dof=18/ rule out 0 ++ & 0 -+

J PC possibilities (0 -+ & 0 ++ ruled out) 0 -- exotic violates parity 0 -+ (  c ” ) 0 ++ DD allowed (  c0 ’ ) 0 +- exotic DD allowed DD allowed (  (3S)) 1 -+ exotic DD allowed 1 ++ (  c1 ’ ) 1 +- (h c ’ ) (  2 ) (  c2 ) 2 ++ DD allowed  c2 ’ ) 2 +- exotic DD allowed

M(  ) can distinguish  -J/  S- & P-waves S-wave:  2 / dof = 43/39 P-wave:  2 / dof = 71/39 q* roll-off q* 3 roll-off (CL=0.1%) (CL= 28%) Shape of M(  ) distribution near the kinematic limit favors S-wave

Possible J PC values (J -+ ruled out) 0 -- exotic violates parity 0 -+ (  c ” ) 0 ++ DD allowed (  c0 ’ ) 0 +- exotic DD allowed DD allowed (  (3S)) 1 -+ exotic DD allowed 1 ++ (  c1 ’ ) 1 +- (h c ’ ) (  2 ) (  c2 ) 2 ++ DD allowed  c2 ’ ) 2 +- exotic DD allowed

X(3872)  D 0 D 0  0 ? 11.3±3.6 sig.evts (>4  ) Bf(B  KX)Bf(X  DD  )=2.2 ± 0.7 ± 0.4x10 -4 D *0  D 0  0 ? M(D 0 D 0  0 ) 1 ++ : DD* in an S-wave  q* 2 ++ : DD  in a D-wave  q* 5 Strong threshold suppression

Possible J PC values (2 ++ ruled out) 0 -- exotic violates parity 0 -+ (  c ” ) 0 ++ DD allowed (  c0 ’ ) 0 +- exotic DD allowed DD allowed (  (3S)) 1 -+ exotic DD allowed 1 ++ (  c1 ’ ) 1 +- (h c ’ ) (  2 ) (  c2 ) 2 ++ DD allowed  c2 ’ ) 2 +- exotic DD allowed 1 ++

can it be a 1 ++ cc state? 1 ++   c1 ’ 3872 Mass is too low  Bf (X      J/  ) >4% is too large (Isospin forbidden)  c1 ’ component of X(3872) is ≤ few%

Intriguing fact M X3872 =3872 ± 0.6 ± 0.5 MeV m D0 + m D0* = ± 1.0 MeV lowest mass charmed meson lowest mass spin=1 charmed meson DD* 2 loosely bound qq color singlets with M = m D + m D* -   u c u c one  exchange attractive for 1 ++ Tornqvist PLB 590, 209 (2004) Deuson? deuteron-like DD* bound state?

X(3872) = D 0 D* 0 bound state? J PC = 1 ++ is favored M ≈ m D0 + m D0* Large isospin violation is natural ( & was predicted) :  |D 0 D* 0 > = 1/  2 (|10> - |00>)  (X   J/  ) <  (X   J/  ) was predicted  (X  D 0 D 0  0 ) too large? Equal mixture of I=1 & I =0 Swanson PLB 598, 197 (2004) Tornqvist PLB 590, 209 (2004) Swanson PLB 588, 189 (2004)

X(3872) conclusion J PC = 1 ++ cc content is small matches most expectations for a D 0 D* 0 bound state CC u c u c a non-qq meson

Are there others? Is the X(3872) a one-of-a-kind curiousity? or the 1 st entry in a new spectroscopy? Look at other B decays  hadrons+J/  B  K  J/  B  K  J/  B  K  J/ 

B  K  J/  in Belle “Y(3940)” M≈3940 ± 11 MeV  ≈ 92 ± 24 MeV M bc S.K. Choi & S.L.Olsen et al. (Belle), PRL94, (2005) M(  J/  ) MeV

Y(3940): What is it? Charmonium? –Conventional wisdom:  J/  should not be a discovery mode for a cc state with mass above DD & DD* threshold! Some kind of  -J/  threshold interaction? –the J/  is not surrounded by brown muck; can it act like an ordinary hadron? J/   Brambilla et al (QWG) hep-ph/

Y(3940): What is it (cont’d) ? another tetraquark? –M ≈ 2m Ds –not seen in Y   J/  (  contains ss) –width too large?? –no  exchange for D S D S s c s c ?? PRL 93, M(  J/  )

Y(3940): What is it (cont’d) ? cc-gluon hybrid? –predicted by QCD, –decays to DD and DD* are suppressed (“open-charm” thresh = m D + m D** = 4.3 GeV) –large hadron+J/  widths are predicted –masses expected to be 4.3 ~ 4.4 GeV (higher than what we see) cc Horn & Mandula PRD (1974) + (many) others

BaBar’s Y(4260) 211 fb -1 data collected at √(s) = GeV  (2S) Y(4260)  110  (2S) evts 125  23 Y(4260) evts J/  sideband Well above DD & DD* threshold but found in an OZI-suppressed mode?? M=4259  8 MeV  = 88  23 MeV B. Aubert et al. (BaBar) hep-ph/

cc summary X(3872): –J PC established as 1 ++ –cc component is small (≤ few %) –all properties consistent with a D 0 D* 0 bound state uc u c a non-standard meson Y(3940) Belle, Y(4260) BaBar cc ????? - Lots to do: determine J PC ; find other modes (DD*, D s D s, …?)

Hardronic charmonium transitions  (  ’      J/  )  70 keV  (  ”      J/  )  50 keV  (  ’   J/  )  5 keV SU F (3) violating  HW (for theorists): How can  (Y3940)   J/  ) and  (Y(4260)      J/  ) be ~1000x larger?  

Baryonium at BES??? u d u u d u

J/    pp (at BES) M(pp) M(pp)-2m p (GeV) M=1859 MeV/c 2  < 30 MeV/c 2 (90% CL)  10  25 3-body phase space acceptance weighted BW Phys. Rev. Lett. 91, (2003)

Baryonium potential & Wave fcn X       ’ should be a strong channel -V 0  (r) Potential barrier G.J. Dung & M.L. Yan hep-ph/ “Rectangularized” Skyrmion-type potential I = 0, J pc =0 -+ pp annihilation M ~ 1860 MeV  ~ 16 MeV  large uncertainties

M(      ’) from J/        ’ 7.7  The  +  -  mass spectrum for  decaying into  +  -  and   BESII Preliminary M = 1834  6  3 MeV  = 68  20  8 MeV

Re-fit to J/    p p including FSI Include FSI curve from A.Sirbirtsev et al. ( Phys.Rev.D71:054010, 2005 ) in the fit (I=0) M =  6.7 MeV  = < 153 In good agreement with X(1835) _

Appendix Other new hidden charm particles from Belle (near 3940!) –X(3940) –Z(3931)

Other new particles from Belle e + e -  J/  + X

X(3940)  DD* seen (  DD &   J/  not seen)

  Z(3931)  DD at Belle 41  11 evts (5.5  ) M=3931  4  2 MeV  20  8  3 MeV sin 4  (J=2)

X(3940)  Y(3940) (maybe the  c ’’ ) ? Z(3931) =  c1 ’ (almost for sure)

Hawaii particles  c ’ X(1860) (  pp) X(3872) Y(3940)

Back-up slides

 c2,  c0 <<  c1 X(3872) production much lower than for other Charmonium states: can set lower limit on B.F.  Can measure absolute B.F.’s of B -  K - X 0 e + e -  B + B - K - X 0 Lower limit on BF(X  J/  ) > 90% C.L 244 fb -1 Very clear J/  and  c signals N J/  = N  c =  c2  c1  c0 J/  Jon Coleman Moriond-QCD March 2005

Kinematic variables CM energy difference: Beam-constrained mass:  B  K  J  B  K  J  B   B ϒ (4S) E cm /2 ee ee M bc EE

1 ++ ll  1 ++ : sin 2  l sin 2  K 1 ++ looks okay! compute angles in X(3872) restframe |cos  l |  2 /dof = 11/9 |cos  |  2 /dof = 5/9

M(  J/  ) look-back plot

Fit cos  l  with 1 ++ MC |cos  l  |  2 /dof=11.9/9