New Hadron Spectroscopies Stephen L Olsen University of

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

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

Hadron “zoo” mesons baryons

Quarks restore economy (& rescue future Fermis from Botany? ) 3 quarks u+2/3 M. Gell-Mann d-1/3 u-2/3 s-1/3 Baryons: qqq p: p: u+2/3 d-1/3 u-2/3 d+1/3 (& 3 antiquarks) d+1/3 s+1/3 Mesons: q q +: u+2/3 d+1//3 -: u-2/3 u+2/3

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

W- 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 Ws-1/3 the 3 s-1/3 quarks in the W- have different color charges & evade Pauli

QCD: Gauge theory for color charges Nambu Gell-Mann & Fritzsch generalization of QED scalar charge: e QCD isovector charge: QED gauge Xform +ie. A 1 vector field (photon) er eb eg QCD gauge Xform + i a li Gi eight 3 x 3 SU(3) matrices 8 vector fields (gluons)

Attractive configurations eijk eiejek i≠ j≠k dij ei ej same as the rules for combing colors to get white: 3 different primary colors color-complementary color eiejek 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 2 nf 11 CA in QCD: CA=3, & this dominates

QED QCD difference Coupling strength a distance

Testing the Standard Model QCD X decrease in aswith distance Electro-Weak W, Z & t masses Z width sin 2 q. W Asymmetries Cross-sections … X QED Lamb-shift g-2 Atomic spectra …

Tests of QED and EW sectors QED (tested @ ppb) Example: (g-2)/2|electron Expt: 1, 159, 652, 188. 4(4. 3)x 10 -12 Theory: 1, 159, 652, 201. 4(28)x 10 -12 Electro-Weak sector (tested @ ~0. 01% level)

Test QCD with 3 -jet events (& deep inelastic scattering) as gluon rate for 3 -jet events should decrease with Ecm

“running” as Why are these people smiling?

Probe QCD from other directions non-qq or non-qqq hadron spectroscopies: Pentaquarks: e. g. an S=+1 baryon u d s (only anti-s quark has S=+1) Glueballs: gluon-gluon color singlet states Multi-quark mesons: qq-gluon hybrid mesons d c c

Pentaquarks “Seen” in many experiments but not seen in just as many others Belle BES Ba. Bar CDF High interest: 1 st pentaquark paper has ~500 citations

Experimental situation is messy (many contradictory results) NA 49 pp @ Ecm=17 Ge. V (fixed tgt) (PRL 92, 052301: 237+ citations!) (1862): qqssd 1862 ± 2 Me. V FWHM = 17 Me. V = 5. 6 COMPASS mp @ Em =160 Ge. V (fixed tgt) 100 s of (1530)s but no hint of (1862) hep-ex/0503033

Pentaquark Scoreboard Positive signals Negative results Also: Belle Compass L 3 Yes: 17 No: 17

Existence of Pentaquarks is not yet established

multi-quark mesons? B K + -J/y y’ + -J/y X(3872) M( J/y)

Seen in 4 experiments CDF X(3872) D 0 X(3872)

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

no cc state fits well 3872 hc ” M too low and G too small hc ’ angular dist’n rules out 1+- cc 1’ G( J/y) way too small y 2 G( cc 1) too small; M( + -) wrong hc 2 y 3 hc should dominate G( cc 2 & DD) too small SLO hep-ex/0407033

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

PC J Possible values -0 -+ 0 +0 exotic violates parity (hc”) DD allowed exotic DD allowed 1 -+ 1 +1 DD allowed (y(3 S)) exotic DD allowed (cc 1’) (hc’) 2 ++ 2 +2 (y 2) (hc 2) DD allowed exotic DD allowed (for J ≤ 2) (cc 0’) (cc 2’)

Possible 0 -- exotic violates parity PC J values -+ 0 0++ 0+- DD allowed exotic DD allowed (hc”) (for J ≤ 2) (cc 0’) 1 - - 1 -+ DD allowed (y(3 S)) exotic DD allowed 2 + 2 (y 2) (hc 2) (cc 2’) ++ 1 +1 (cc 1’) (hc’) 2++ 2+- DD allowed exotic DD allowed

Use 250 fb-1 ~275 M BB prs X(3872) + -J/y y’ + -J/y Signal (47 ev) Sidebands (114/10 = 11. 4 ev)

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

Search for X(3872) J/y

Kinematic variables B B K + -J/y e+ e- B Ecm/2 ϒ(4 S) Ecm/2 DE CM energy difference: B K + -J/y Beam-constrained mass: Mbc

Select B K J/y B Kcc 1; cc 1 J/y X(3872)? M( J/y) 13. 6 ± 4. 4 X(3872) J/y evts (>5 significance) Mbc Bf(X J/y) Bf(X J/y) Mbc =0. 14 ± 0. 05

Evidence for X(3872) + - 0 J/y (reported last summer hep-ex/0408116) 12. 4 ± 4. 2 evts B-meson yields vs M( + - 0) Br(B 3 J/y) Br(B 2 J/y) = 1. 0 ± 0. 5 Large (near max) Isospin violation!!

Evidence for C=+1 is overwhelming • B J/y only allowed for C=+1 • same for B ”w”J/y (reported earlier) • M( ) for X + -J/y looks like a

Possible JPC values (C=-1 ruled out) 0 -- exotic violates parity 1 - - DD allowed (y(3 S)) 2 - (y 2) -+ 0 (hc”) 1 -+ exotic DD allowed 0++ DD allowed (cc 0’) ++ 1 (cc 1’) 2++ + 2 DD allowed (hc 2) (cc 2’) 0+- exotic DD allowed 1+- (hc’) 2+- exotic DD allowed

Angular Correlations Jz=0 X 3872 J=0 K J/y

Strategy: for each JPC, find a distrib 0 if we see any events there, we can rule it out Rosner (PRD 70 094023) Bugg (PRD 71 016006)

0 -+ : sin 2 q sin 2 y c 2/dof=18/9 q |cosq| c 2/dof=34/9 y safe to rule out 0 -+ |cosy|

0++ ql In the limit where X(3872), , & J/y rest frames coincide: d. G/dcosql sin 2 ql c 2/dof = 41/9 rule out 0++ |cosql |

++ 1 1++: sin 2 ql sin 2 c compute angles in X(3872) restframe c 2/dof = 11/9 ql K c 1++ looks okay! |cosql| c 2/dof = 5/9 |cosc|

Possible JPC values (0 -+ & 0++ ruled out) 0 -- exotic violates parity 0 -+ 0++ (hc”) DD allowed 1 - - 1 -+ DD allowed (y(3 S)) 2 - (y 2) exotic DD allowed (cc 0’) ++ 1 (cc 1’) 2++ + 2 DD allowed (hc 2) (cc 2’) 0+- exotic DD allowed 1+- (hc’) 2+- exotic DD allowed

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

M( ) can distinguish -J/y S- & P-waves S-wave: c 2/dof = 43/39 (CL= 28%) P-wave: c 2/dof = 71/39 (CL=0. 1%) q* roll-off Shape of M( ) distribution near the kinematic limit favors S-wave q*3 roll-off

Possible JPC values (J-+ ruled out) 0 -- exotic violates parity 0 -+ 0++ (hc”) DD allowed 1 - - 1 -+ DD allowed (y(3 S)) exotic DD allowed 2 - (y 2) 2 - + (hc 2) (cc 0’) ++ 1 (cc 1’) 2++ DD allowed (cc 2’) 0+- exotic DD allowed 1+- (hc’) 2+- exotic DD allowed

Search for 0 0 0 X D D

Select 0 0 0 B D D events D*0 D 0 0? y r a n 22± 7 signal evts i m i l e r Bf(B KX)Bf(X D*D)=2. 2± 0. 7± 0. 4 x 10 P |DE| -4 |DE|

X DD rules out 2++ • 1++ : DD* in an S-wave q* • 2++ : DD* (or DD ) in a D-wave q*5 Strong threshold suppression

Possible JPC values (2++ ruled out) 0 -- 0+- exotic violates parity 0 -+ 0++ (hc”) DD allowed 1 - - 1 -+ DD allowed (y(3 S)) exotic DD allowed ++ 1 (hc’) 2 - (y 2) 2 - + (hc 2) 2++ 2+- DD allowed exotic DD allowed (cc 0’) ++ 1 (cc 1’) (cc 2’) exotic DD allowed 1+-

a 1++ cc state? • 1++ cc 1’ – Mass is off – cc 1’ r J/y violates Isospin, should be suppressed. 3872 G(X J/y)/G(X J/y) Theory: Expt: ~ 30 0. 14 ± 0. 05 cc 1’ component of the X(3872) is ≤ few %

Intriguing fact MX 3872 =3872 ± 0. 6 ± 0. 5 Me. V m. D 0 + m D 0* = 3871. 2 ± 1. 0 Me. V 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)? There is lots of literature about this possibility deuteron: Hadronium attractive nuclear force p n loosely bound 3 -q color singlets with Md = mp+mn- e N. Tornqvist hep-ph/0308277 (dueson): attractive force? ? D D* loosely bound q-q color singlets with M = m. D + m. D* - d

X(3872) = D 0 D*0 bound state? • JPC = 1++ is favored • M≈m. D 0 + m. D 0* Tornqvist PLB 590, 209 (2004) Swanson PLB 588, 189 (2004) • Maximal Isospin violation is natural: |I=1; Iz= 0> =1/ 2(|D+D*->+ |D 0 D*0>) |I=0; Iz= 0> =1/ 2(|D+D*-> - |D 0 D*0>) |D 0 D*0> = 1/ 2( |10> - |00>) Equal mixture of I=1 & I =0 • G(X J/y) < G(X J/y) is expected Swanson PLB 598, 197 (2004)

X(3872) conclusion • Not a cc state CC • Most likely a D 0 D*0 bound state d c c d 1 st well established tetraquark

Are there others? Look at other B decays hadrons+J/y B K h J/y B K w J/y B K …

B K w. J/y in Belle “Y(3940)” M≈3940 ± 11 Me. V G≈ 92 ± 24 Me. V

Y(3940): What is it? • Charmonium? – Conventional wisdom: w. J/y should not be a discovery mode for a cc state with mass above DD & DD* threshold! • Some kind of w-J/y threshold interaction? – the J/y is not surrounded by brown muck; can it act like an ordinary hadron? J/y w

Y(3940): What is it? (continued) • another tetraquark? – M ≈ 2 m. Ds – not seen in Y h. J/y • (h contains ss) ? ? PRL 93, 041801 M(h J/y) – width too large? ? – need to search for Y(3949) DSDS c s

Y(3940): What is it? (continued) • cc-gluon hybrid? – – predicted by lattice QCD, decays to DD and DD* are suppressed large hadron+J/y widths are predicted masses expected to be 4. 3 ~ 4. 4 Ge. V (higher than what we see) c c

Summary • X(3872): d c PC ++ – J established as 1 d c – 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: c c • determine JPC • search for other decay channels (DD*, Ds. Ds, …)

Other hadronium states? fitted peak location J/y pp in the BES expt J. Z. Bai PRL 91, 022001(2003) +3 +5 M=1859 -10 -25 Me. V/c 2 G < 30 Me. V/c 2 (90% CL) c 2/dof=56/56 0 0. 1 0. 2 M(pp)-2 mp (Ge. V) 0. 3 acceptance

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

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

Hence the name: Quantum Chromo Dynamics q q q

confinement

Grand Unification? QED EW s

“Data, I need data. I can’t make bricks without clay” 1 fb -1/day 10 34

Strategy: for each JPC, find a distrib 0 if we see any events there, we can rule it out Ex: 1 --: sin 2 q Km y’ is 1 -- Use y’ to check accept. y’: c 2/dof = 8. 9/9 q m K ompute angles in J/y restframe D. V. Bugg hep-ph/0410168 v 2

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

1+- and 2 -use J/y helicity angle q. J/y X For the y’ + -J/y, this should be ~flat K q. J/y |cosq. J/y|

1+- and 2 -1+-: sin 2 q c 2/dof=32/9 |cosq. J/y| J/y 2 --: sin 2 q. J/y cos 2 q. J/y c 2/dof=20/9 |cosq. J/y| can rule out 1+- (Cl < 0. 1%)

Narrow multi-quark mesons? • Ds. J(2317) & Ds. J(2457) CLEO M(Ds ) M(Ds* ) • X(3872) J/y M( J/y)

What are the Ds. J states? Belle found B D Ds. J(2317) D Ds. J(2457) and Ds. J(2457) Ds

Angular analysis for B D Ds. J Dsp(g) J=0 z Jz=0 Ds. J(2317) Ds 0 ( ) Ds. J(2460) Ds J=1 Ds. J(2317) = 0+ Ds. J(2547) = 1+ J=0 J=2

Ds. J fit into cs spectrum (with a mass shift) Ds. J(2547) = 1+ Ds. J(2317) = 0+

Ds. J states are likely ordinary L=1 cs mesons Theory got the masses wrong