Nonstandard mesons Stephen L. Olsen University of Hawai’i cc u d u u d u uc u c tetra-quarks meson-meson molecules q q – q q diquark pairs q q-gluon hybrids nucleon-antinucleon baryonium uc u c

This talk Candidate non-standard mesons with hidden charm from Belle & BaBar Candidate baryonium meson from BES cc uc u c u d u u d u probably no time for:

Concentrate on “hidden charm” systems standard cc mesons are: –best understood theoretically –narrow & non overlapping c c systems are prolifically 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

Charmonium primer  (  ’      J/  )  70 keV  (  ”      J/  )  50 keV  (  ’   J/  )  5 keV SU F (3) violating    These states have all been identified These states have not yet been found Hadronic transitions   (  ’    J/  )  0.3 keV isospin violating EM transitions  (E1)  100~300 keV  (allowed M1)  1 keV DD ( * ) decays dominate  ~wide (10’s of MeV) Below DD ( * ) thresholds  ~narrow (~<MeV )

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)

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

Is it a cc meson? 3872 MeV If so, it must 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  k    x  J  

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 ’ (the only possibility) 3872  Bf(X      J/  )>4% is very large for an isospin-violating channel (Isospin violating)

Expectations for  ’ c1  (  ’ c1   J/  )  11 keV Barnes Godfrey PRD  (  ’ c1      J/  ) = ?  (  ’    J/  )  0.3 keV (“educated” guess?) Bf(X   J/  ) Bf(X   J/  )  30 ~ 40 Bf(X   J/  ) Bf(X   J/  ) =0.14 ± 0.05 Expect: Measmnt: >200x discrepancy  c1 ’ component of X(3872) is  few% (at most?) can our “education” really be this bad?

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? Bf(B 0  K 0 X 3872 )/Bf(B +  K + X 3872 ) too large? Equal mixture of I=1 & I =0 Swanson PLB 598, 197 (2004) Tornqvist PLB 590, 209 (2004) Swanson PLB 588, 189 (2004) Braaten & Kusunoki PR D71, predict: < 0.08 BaBar measurement (hep-ex/ ): 0.5  0.3

diquark-antidiquark? Maiani et al predict:  M = M(X u ) – M(X d ) = 8  3 MeV BaBar (hep-ex/ ) reports:  M = 2.7  1.3  0.2 MeV uc u c dc d c Maiani etal predict a doublet of states PRD 71, (2005) Xu=Xu= Xd=Xd= B+K+XuB+K+Xu B0K0XdB0K0Xd BaBar

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: (SU(3)-violating)  J/  decay  should not be a discovery mode for a cc state with mass above DD & DD* threshold! eg.Brambilla et al (QWG) hep-ph/ 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 can occur –masses expected to be 4.3 ~ 4.4 GeV (higher than what we see) Horn & Mandula PRD others

J/  sideband Well above DD & DD* threshold but wide & found in a suppressed mode?? M=4259  8 MeV  = 88  23 MeV B. Aubert et al. (BaBar) hep-ph/ Y(4260) GeV 4.26 GeV not seen in  (e + e -  hadrons) at Ecm =4.26 GeV J.Z. Bai et al. (BESII) PRL BES BaBar’s Y(4260)  (e + e -  hadrons)

summary X(3872): –Existence well established –J PC = 1 ++ –Br(X      J/  ) too high for charmonium –Br(X  D 0 D 0  0 ) too high for molecule –Br(B 0  K S X 3872 ) also too high for molecule(?) –  M too small for diquarks? –Mass too low for hybrid by a factor of more than 200! still under study The more we learn more about it the more puzzling it becomes. (M(X u ) (from B +  K + X u ) - M(X d ) (from B 0  K S X d )

summary (cont’d) Y(3940) Belle –  ( Y 3940   J/  too high for charmonium –Mass too low for a hybrid Y(4260) BaBar –  (y 4260      J/  also way too high –1 --, but not seen in e + e -  hadrons by factors of ~10 3

Mahalo enjoy mid-autumn festival in Hawaii X(3872) Y(3940) Y(4260) … Homeless mesons 但願人長久 千里共嬋娟

Back-up slides

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   +  -  mass spectrum for  +  -  &   modes BESII Preliminary M = 1834  6  3 MeV  = 68  20  8 MeV

I=0 FSI In good agreement with X(1835) M =  6.7 MeV  = < 153 Re-fit J/    p p including FSI _ Sirbirtsev et al. (PRD )

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)

 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

Y(3940): What is it (cont’d) ? a molecule? –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 can occur –masses expected to be 4.3 ~ 4.4 GeV (higher than what we see) cc Horn & Mandula PRD (1978) + (many) others