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Homeless mesons X3872 Y3940 Y4260 Stephen L. Olsen University of Hawai’i
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History: ( sub-atomic particles) 1932: proton & neutron..all we need??? 1937: muon “Who ordered that?” 1947: pion predicted in 1935 1950’s: , , , , ,… “Had I foreseen that, I would have gone into botany” – Fermi chadwick Fermi TingPetersJones Rabi Yukawa Joliet-Curie
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Hadron “zoo” mesons baryons
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Quarks restore economy ( & rescue future Fermis from Botany?) (& 3 antiquarks) Mesons: qq p: u +2/3 p: u -2/3 +:+: d -1/3 u +2/3 d +1/3 u -2/3 d +1//3 u +2/3 -:-: u -2/3 d +1/3 s +1/3 u +2/3 d -1/3 s -1/3 Gell-Mann 3 quarks Zweig Baryons: qqq
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Fabulously successful, but… quarks are not seen why only qqq and qq combinations? What about spin-statistics?
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s -1/3 three s-quarks in the same quantum state Das ist verboten!!
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The strong interaction “charge” of each quark comes in 3 different varieties Y. Nambu O. Greenberg s -1/3 the 3 s -1/3 quarks in the - have different color charges & evade Pauli --
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QCD: Gauge theory for color charges generalization of QED + i e A + i i G i QED gauge Xform QCD gauge Xform eight 3x3 SU(3) matrices 8 vector fields (gluons) 1 vector field (photon) scalar charge: e isotriplet charge: erebegerebeg QED QCD Yang Mills Nambu Fritzsch & GellMann
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Attractive configurations ijk e i e j e k i ≠ j ≠ k ij e i ejej same as the rules for combining colors to get white : add 3 primary colors or add color+complementary color antiquarks: anticolor charges Hence the name: Quantum Chromodynamics quarks: e i e j e k color charges ejej eiei ekek
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Difference between QED & QCD QED: photons have no charge QCD: gluons carry color charges gluons interact with each other Coupling strengths distance
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Test QCD with 3-jet events (& deep inelastic scattering) rate for 3-jet events should decrease with E cm gluon ss
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“running” s Why are these people smiling?
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Probe QCD from other directions Proposed non-qq or non-qqq hadron spectroscopies: Pentaquarks: e.g. an S=+1 baryon (only anti-s quark has S=+1) Glueballs: gluon-gluon color singlet states Multi-quark mesons: qq-gluon hybrid mesons uc u c cc u d u s d
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Pentaquarks “Seen” in many experiments BaBar CDF but not seen in just as many others High interest: 1 st pentaquark paper has ~500 citations Belle BES
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Experimental situation is messy (some contradictory experiments) SAPHIR (2004) 4.8 M(nK + )(GeV) Counts/4 MeV nKKγp s CLAS (2005) Same reaction
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Some groups contradict themselves 5.2 CLAS-D (2003) no signal CLAS (2005) ???
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Pentaquark Scoreboard Positive signals Negative results Also: Belle Compass L3 CLAS Yes: 17 No: 18
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Plenary speaker at LP05 “The pentaquark is not in good health, but it is still alive.” - Volker D Burkert Jefferson Lab
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This talk: non-standard mesons with “hidden charm” 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)
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Thanks to KEKB we have lots of B mesons (>1M BB pairs/day) >1fb -1 /day Design: 10 34
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Primer on Charmonium
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Charmonium r mesons formed from c- and c-quarks c-quarks are heavy: m c ~ 1.5 GeV 2m p velocities small: v/c~1/4 non-relativistic QM applies cc
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QM of cc mesons cc r What is V(r) ?? derive from QCD quantum chromodynamics
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“Cornell” potential ~0.1 fm G.S.Bali hep-ph/0010032 “confining” large distance component slope~1GeV/fm 1/r “coulombic” short distance component cc r V(r) 2 parameters: slope & intercept
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Charmonium spectrum
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1 -- Charmonium states J/ ’’ D-meson + anti-D meson mass threshold ”” “narrow” ( ~100KeV) e+e+ e-e- Directly accessible via e + e - annihilation (e + e - hadrons) “narrow” ( ~300KeV) “wide” ( ~25 MeV) ” DD decay channel is open DD) 25MeV
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P-wave states Gamma energy spectrum from ’ X decays Gaiser et al (Crystal Ball) PRD 34 711 accessible via E1 transitions from ’ 2 3 S 1 ( ’ ) 1 3 P 2 ( c2 ) 17 keV 2 3 S 1 ( ’ ) 1 3 P 1 ( c1 ) 24 keV 2 3 S 1 ( ’ ) 1 3 P 0 ( c0 ) 24 keV 1 3 P 2 ( c2 ) 1 3 S 1 (J/ ) 420 keV 1 3 P 1 ( c1 ) 1 3 S 1 (J/ ) 290 keV 1 3 P 0 ( c0 ) 1 3 S 1 (J/ ) 120 keV E1 Transition Partial width Calculable from”1 st principles” Good agreement with measurements
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Hadronic transitions ( ’ J/ ) 70 keV “allowed” ( ” J/ ) 50 keV “allowed” ( ’ J/ ) 5 keV SU F (3) violating ( ’ J/ ) 0.3 keV isospin violating “reasonable” agreement between measurement & theory c.f. Kuang & Yan PRD 41 155
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Recent results 1 3 D 1 1 3 P 1 seen by CLEO hep-ex/0509030 (meas) = 75 18 keV (theor) 59~77 keV 1 1 P 1 found by CLEO hep-ex/0508037 properties as expected 2 3 P 2 found by Belle hep-ex/0507033 properties as expected 2 1 S 0 found by Belle S.K.Choi et al PRL 89 102001 properties as expected
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The potential model for cc charmonium mesons is robust and reliable
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The X(3872) ???? Study J/ produced in B K J/ decays
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The X(3872) B K J/ M( J ) ’ J/ X(3872) J/ S.K. Choi et al PRL 91, 262001
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Its existence is well established seen in 4 experiments X(3872) CDF X(3872) D0 hep-ex/0406022 9.4 11.6
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Is it a cc meson? These states are already identified 3872 MeV Could it be one of these?
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no obvious cc assignment 3872 c”c” 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/0407033 hc’hc’ c1 ’ 22 22 33
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go back to square 1 Determine J PC quantum numbers of the X(3872) with minimal assumptions
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J PC possibilities (for J ≤ 2) 0 -- exotic violates parity 0 -+ ( c ” ) 0 ++ DD allowed ( c0 ’ ) 0 +- exotic DD allowed 1 - - DD allowed ( (3S)) 1 -+ exotic DD allowed 1 ++ ( c1 ’ ) 1 +- (h c ’ ) 2- -(2)2- -(2) 2 - + ( c2 ) 2 ++ DD allowed c2 ’ ) 2 +- exotic DD allowed
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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 1 - - DD allowed ( (3S)) 1 -+ exotic DD allowed 1 ++ ( c1 ’ ) 1 +- (h c ’ ) 2- -(2)2- -(2) 2 - + ( c2 ) 2 ++ DD allowed c2 ’ ) 2 +- exotic DD allowed
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Strong evidence for C=+1 13.6 ± 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)
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J PC possibilities (C=-1 ruled out) 0 -- exotic Violates parity 0 -+ ( c ” ) 0 ++ DD allowed ( c0 ’ ) 0 +- exotic DD allowed 1 - - DD allowed ( (3S)) 1 -+ exotic DD allowed 1 ++ ( c1 ’ ) 1 +- (h c ’ ) 2 - - ( 2 ) 2 - + ( c2 ) 2 ++ DD allowed c2 ’ ) 2 +- exotic DD allowed
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Angular Correlations K J/ e e J=0 X 3872 J z =0 z Rosner (PRD 70 094023) Bugg (PRD 71 016006) Suzuki, Pakvasa (PLB 579 67)
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ll |cos l | 2 /dof = 34/9 |cos | |cos | 2 /dof=34/9 0 ++ 0 -+ rule out 0 ++ & 0 -+ J k x J
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J PC possibilities (0 -+ & 0 ++ ruled out) 0 -- exotic violates parity 0 -+ ( c ” ) 0 ++ DD allowed ( c0 ’ ) 0 +- exotic DD allowed 1 - - DD allowed ( (3S)) 1 -+ exotic DD allowed 1 ++ ( c1 ’ ) 1 +- (h c ’ ) 2 - - ( 2 ) 2 - + ( c2 ) 2 ++ DD allowed c2 ’ ) 2 +- exotic DD allowed
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Fits to the M( ) Distribution X J/ in P-wave has a q* 3 centrifugal barrier X J/ q*
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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
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Possible J PC values (J -+ ruled out) 0 -- exotic violates parity 0 -+ ( c ” ) 0 ++ DD allowed ( c0 ’ ) 0 +- exotic DD allowed 1 - - DD allowed ( (3S)) 1 -+ exotic DD allowed 1 ++ ( c1 ’ ) 1 +- (h c ’ ) 2 - - ( 2 ) 2 - + ( c2 ) 2 ++ DD allowed c2 ’ ) 2 +- exotic DD allowed
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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
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Possible J PC values (2 ++ ruled out) 0 -- exotic violates parity 0 -+ ( c ” ) 0 ++ DD allowed ( c0 ’ ) 0 +- exotic DD allowed 1 - - DD allowed ( (3S)) 1 -+ exotic DD allowed 1 ++ ( c1 ’ ) 1 +- (h c ’ ) 2 - - ( 2 ) 2 - + ( c2 ) 2 ++ DD allowed c2 ’ ) 2 +- exotic DD allowed 1 ++
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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) M=3872 MeV is too low, especially now that we know that M( c2 ’ )=3931 4 MeV
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Expectations for ’ c1 ( ’ c1 J/ ) 11 keV Barnes Godfrey PRD 69 054008 ( ’ 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: Meas: >200x discrepancy c1 ’ component of X(3872) is few% (at most?) can our “education” really be this bad?
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Intriguing fact M X3872 =3872 ± 0.6 ± 0.5 MeV m D0 + m D0* = 3871.2 ± 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?
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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, 074005 predict: < 0.08 BaBar measurement (hep-ex/0507090): 0.5 0.3
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diquark-antidiquark? Maiani et al predict: M = M(X u ) – M(X d ) = 8 3 MeV BaBar (hep-ex/0507090) reports: M = 2.7 1.3 0.2 MeV uc u c dc d c Maiani etal predict a doublet of states PRD 71,014028 (2005) Xu=Xu= Xd=Xd= B+K+XuB+K+Xu B0K0XdB0K0Xd BaBar
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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/
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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, 182002 (2005) M( J/ ) MeV
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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/0412158 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 17 898 others
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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/0506081 Y(4260) 10.58 GeV 4.26 GeV not seen in (e + e - hadrons) at Ecm =4.26 GeV J.Z. Bai et al. (BESII) PRL 88 101802 BES BaBar’s Y(4260) (e + e - hadrons)
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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 )
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other odd-balls 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
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3872 Charmonium chalet Isospin violators not welcome Fussy! Y3940 Y4260 Looking for a home:
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3872 rats! Molecule Manors DD Y3940 Y4260
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3872 Hydrid heaven M<4.2 GeV need not apply Fat Cats! Y3940 Y4260
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3872 Diquark dives *#!?&%$! Doublets only no singlets! Y3940Y4260
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Conclusion either: –The “standard model” for charmonium mesons needs major revision or: –There is a new hadron spectroscopy in the 3.5~4.5 GeV mass region Opportunities for CLEO-c & BES-III ???
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Back-up slides
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X u – X d Mass difference?: M Xu – M ’ = 185.7 0.6 MeV M Xd – M ’ = 184.0 1.3 MeV M(X u ) – M(X d ) = 0.8 1.4 MeV Belle: Preliminary
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Another one? e + e - J/ + X >4 )peak at M=3940 11 MeV N=148 33 evts Width consistent w/ resolution (= 32 MeV) cc cc c0 cc ‘ ‘ What is it? c0 ? c ?? ‘“
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Look at e + e - J/ D(D ( * ) ) Reconstruct a J/ & a D use D 0 K - + & D + K - + + Determine recoil mass
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Look at M(DD ( * ) ) DD* DD 3940 MeV 9.9 ± 3.3 evts (4.5 ) 4.1 ± 2.2 evts (2.1 ) c0 DD* ‘ c DD “
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Other hadronium states? M=1859 MeV/c 2 < 30 MeV/c 2 (90% CL) J/ pp in the BES expt M(pp)-2m p (GeV) 00.10.20.3 acceptance 2 /dof=56/56 fitted peak location +3 +5 10 25 J.Z.Bai PRL 91,022001(2003)
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