New Hadron Spectroscopies Stephen L. Olsen University of Hawai’i dc d ccc u d u s d

History: 1930’s: proton & neutron..all we need??? 1950’s: , , , , ,  … “Had I foreseen that, I would have gone into botany” – Fermi 1960’s: The 8-fold way “3 quarks for Mister Mark” 1970’s add charmed particles 1980’s & beauty 1990’s & (finally?) top chadwick Fermi Gell-Mann RichterTing Lederman PetersJones

Hadron “zoo” mesons baryons

Quarks restore economy ( & rescue future Fermis from Botany?) (& 3 antiquarks) Baryons: qqq 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 M. Gell-Mann 3 quarks

Fabulously successful, but… quarks are not seen why only qqq and qq combinations? What about spin-statistics?

 s -1/3 2 of these s-quarks are in the same quantum state Das ist verboten!!

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 --

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 isovector charge: erebegerebeg QED QCD Nambu Gell-Mann & Fritzsch

Attractive configurations  ijk e i e j e k i ≠ j ≠ k  ij e i ejej same as the rules for combing colors to get white: 3 different primary colors color-complementary color e i e j e k  color charges Hence the name: Quantum Chromodynamics

Difference between QED & QCD QED: photons have no charge QCD: gluons carry color charges gluons interact with each other

Vacuum polarization QED vs QCD 2n f 11C A in QCD: C A =3, & this dominates

QED  QCD difference  Coupling strength distance

Testing the Standard Model QCD X Electro-Weak X QED decrease in  s with distance Lamb-shift g-2 Atomic spectra … W, Z & t masses Z width sin   W Asymmetries Cross-sections …

Tests of QED and EW sectors Electro-Weak sector ~0.01% level) QED ppb) Example: (g-2)/2| electron Expt: 1,159,652,188.4(4.3)x Theory: 1,159,652,201.4(28)x10 -12

Test QCD with 3-jet events (& deep inelastic scattering) rate for 3-jet events should decrease with E cm gluon ss

“running”  s Why are these people smiling?

Probe QCD from other directions 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 dc d c cc u d u s d

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

Experimental situation is messy (many contradictory results) NA49 E cm =17 GeV (fixed tgt) (PRL92, : 237+ citations!) COMPASS  E  =160 GeV (fixed tgt) 1862 ± 2 MeV FWHM = 17 MeV  = 5.6  (1862): qqssd 100s  of  (1530)s but no hint of  (1862) hep-ex/

Pentaquark Scoreboard Positive signals Negative results Also: Belle Compass L3 Yes: 17 No: 17

Existence of Pentaquarks is not yet established

multi-quark mesons? B  K     J/  M(  J  )  ’      J/  X(3872)

Seen in 4 experiments X(3872) CDF X(3872) D0 hep-ex/

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

no cc state fits well 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/

back to square 1 Determine J PC quantum numbers of the X(3872)

Possible J PC values (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

Possible J PC values (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

Use 250 fb -1  ~275M BB prs Signal (47 ev) Sidebands (114/10 = 11.4 ev) X       J/   ’      J/ 

Areas of investigation Search for radiative decays Angular correlations in X   J/  decays Fits to the M(  ) distribution Search for X(3872)  D* 0 D 0

Search for X(3872)   J/ 

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

Select B  K  J/  B  K  c1 ;  c1   J/  X(3872)? 13.6 ± 4.4 X(3872)   J/  evts (>5  significance) M(  J/  ) Bf(X   J/  ) Bf(X   J/  ) =0.14 ± 0.05 M bc

Evidence for X(3872)        J/   reported last summer hep-ex/ ) 12.4 ± 4.2 evts B-meson yields vs M(       ) Br(B  3  J/  ) Br(B  2  J/  ) = 1.0 ± 0.5 Large (near max) Isospin violation!!

Evidence for C=+1 is overwhelming B   J/  only allowed for C=+1 same for B  ”  ”J/  (reported earlier) M(  ) for X      J/  looks like a 

Possible J PC values (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

Strategy: for each J PC, find a distrib  0 if we see any events there, we can rule it out Rosner (PRD ) Bugg (PRD )

: sin 2  sin 2  safe to rule out 0 -+    2 /dof=18/9 |cos  | |cos  |  2 /dof=34/9

0 ++ ll In the limit where X(3872), , & J/  rest frames coincide: d  /dcos  l   sin 2  l  |cos  l  | rule out 0 ++  2 /dof = 41/9

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

Possible J PC values (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

Fits to the M(  ) Distribution X   J/  in P-wave has a q* 3 centrifugal barrier X J/   q*

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

Search for X  D 0 D 0  0

Select B  D 0 D 0  0 events |  E| 22±7 signal evts Bf(B  KX)Bf(X  D*D)=2.2 ± 0.7 ± 0.4x10 -4 Preliminary D *0  D 0  0 ?

X  DD  rules out : DD* in an S-wave  q* 2 ++ : DD* (or 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 ++

a 1 ++ cc state? 1 ++   c1 ’ –Mass is off –  c1 ’   J/  violates Isospin, should be suppressed  (X   J/  )/  (X   J/  ) Theory: ~ 30 Expt: 0.14 ± 0.05  c1 ’ component of the 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 X(3872) is very near DD* threshold. is it somehow related to that?

hh bound states (hadronium)? pn DD* deuteron: loosely bound 3-q color singlets with M d = m p +m n -  Hadronium (dueson) : loosely bound q-q color singlets with M = m D + m D* -  attractive nuclear force attractive force?? There is lots of literature about this possibility   N. Tornqvist hep-ph/

X(3872) = D 0 D* 0 bound state? J PC = 1 ++ is favored M≈m D0 + m D0* Maximal Isospin violation is natural: |I=1; I z = 0> =1/  2(|D + D* - >+ |D 0 D* 0 >) |I=0; I z = 0> =1/  2(|D + D* - > - |D 0 D* 0 >)  |D 0 D* 0 > = 1/  2( |10> - |00>)  (X   J/  ) <  (X   J/  ) is expected 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 Not a cc state Most likely a D 0 D* 0 bound state CC d c d c 1 st well established tetraquark

Are there others? Look at other B decays  hadrons+J/   B  K  J/   B  K  J/   B  K  J/   B  K …

B  K  J/  in Belle “Y(3940)” M≈3940 ± 11 MeV  ≈ 92 ± 24 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/  

Y(3940): What is it? (continued) another tetraquark? –M ≈ 2m Ds –not seen in Y   J/  (  contains ss) –width too large?? –need to search for Y(3949)  D S D S s c s c ?? PRL 93, M(  J/  )

Y(3940): What is it? (continued) cc-gluon hybrid? –predicted by lattice QCD, –decays to DD and DD* are suppressed –large hadron+J/  widths are predicted –masses expected to be 4.3 ~ 4.4 GeV (higher than what we see) cc

Summary X(3872): –J PC established as 1 ++ –cc component is small (≤ few %) –all measured properties are consistent with a D 0 D* 0 bound state  1 st established tetraquark! Y(3940): –No obvious cc assignment –tetraquark seems unlikely –cc-gluon hybrid? –Lots to do: determine J PC search for other decay channels (DD*, D s D s, …) dc d c cc

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) acceptance  2 /dof=56/56 fitted peak location  10  25 J.Z.Bai PRL 91,022001(2003)

The case of the mystery meson Stephen L. Olsen University of Hawai’i

SU(3) S>0 S<0 baryons octets & decuplets Meson octets

Hence the name: Quantum Chromo Dynamics qqqqqq qqqqqq

confinement

Grand Unification? s QED EW

“Data, I need data. I can’t make bricks without clay” fb -1 /day

Strategy: for each J PC, find a distrib  0 if we see any events there, we can rule it out  Ex: 1 -- : sin 2  K  K compute angles in J/  restframe D.V. Bugg hep-ph/ v2  ’  2 /dof = 8.9/9 Use  ’ to check accept.  ’ is 1 --

|cos  Kl | for X(3872) events X(3872) is not 1 -- ! expect 2~3evts/bin background scaled from sidebands fit with sin 2  Kl + bkgd  2 /dof = 45/9 see 8 evts/bin

1 +- and 2 -- use J/  helicity angle  J/  K X J/   J/  |cos  J/  | For the  ’      J/ , this should be ~flat

1 +- and 2 -- can rule out 1 +- (Cl < 0.1%) |cos  J/  | 1 +- : sin 2  J/  2 -- : sin 2  J/  cos 2  J/   2 /dof=32/9  2 /dof=20/9 |cos  J/  |

Narrow multi-quark mesons? D sJ (2317) & D sJ (2457) X(3872)   J/  CLEO M(D s  ) M(D s *  ) M(  J  )

What are the D sJ states? Belle found B  D D sJ (2317)  D D sJ (2457) and D sJ (2457)   D s

Angular analysis for B  D D sJ D sJ  D s  (  ) J=1 J=0 D sJ (2317)  D s  0 J=1 J=2 D sJ (2460)  D s  z J z =0 D sJ (2317) = 0 + D sJ (2547) = 1 + J=0 

D sJ fit into cs spectrum (with a mass shift) D sJ (2547) = 1 + D sJ (2317) = 0 +

D sJ states are likely ordinary L=1 cs mesons Theory got the masses wrong