XY but not Z Stephen L Olsen states
XY (but not Z) Stephen L. Olsen states, experimental overview University of Hawai’i (member: BES & Belle expts)
X & Y mesons X(3872) B K p+p-J/ ’ Y(4260) Belle e+e- g. ISRp+p-J/ Ba. Bar Belle 72) Y(4008)? X(38 M(p+p-J/ )-M(J/ ) Belle (Decay to final states with a cc pair & Sqi=0 ) Y(3940) M(p+p-J/ ) Ba. Bar B K w. J/ e+e- g. ISRp+p- ’ Y(4350) & Y(4660) Ba. Bar M(w. J/ ) Belle M(w. J/ ) X(3940) e+e- DD*J/ M(p+p- ’) X(4160) e+e- D*D*J/ Belle Y(4630) CDF B K f. J/ Belle M(DD*) Y(4140) M(D*D*) M(f. J/ ) e+e- g. ISRLc. Lc Belle M(Lc. Lc)
Neutral cc X & Y mesons Name JPC G (Me. V) Decay modes Expts comment X(3872) 1++ <2. 3 pp. J/ ; g. J/ ; DD* Belle/CDF/D 0/Ba. Bar DD* molecule? X(3940) 0? + ~37 DD* (not DD, w. J/ ) Belle hc’’(? ) Y(3940) ? ? + ~30 (not DD*) Belle/Ba. Bar X(4160) 0? + ~140 (not DD, DD*) Belle Y(4008) 1 -- ~225 pp. J/ Belle Y(4260) 1 -- ~80 pp. J/ (not pp ’) Ba. Bar/CLEO/Belle Y(4350) 1 -- ~75 pp ’ Y(4660) 1 -- ~50 pp ’; Lc. Lc (? ) Belle @Lc. Lc threshold Y(4140) ? ? + ~12 f. J/ CDF @f. J/ threshold w. J/ D*D* (not pp. J/ ) hc’’’(? ) ccg hybrid? Ba. Bar/Belle
What’s new? • Belle sees a gg w. J/ peak @ ~3915 Me. V – New to this meeting • Belle measurements of (e+e- D*Dp) – New to this meeting (G. Pakhlova’s Thurs talk) • CDF evidence for Y(4140) f. J/ – Moriond QCD Kay Yi’s talk this session • Z(4430)+ p+ ’; Z 1(4050)+ & Z 2(4250)+ p+cc 1 – controversy? Chistov & Patrigani in the next session • Ba. Bar results for X(3872) g. J/ & g ’ • Mass measurements from CDF & Belle
The states near 3940 Me. V not seen in w. J/ X(3940) probably different e+e- J/ DD* M(DD*) M = 3942 +7 -6 ± 6 Me. V Gtot = 37 +26 -15 ± 12 Me. V Nsig =52 +24 -16 -circa 2005 - not seen in DD* Probably the cc 2’ B K w. J/ gg Y(3940) M(w. J/ ) M≈3940 ± 11 Me. V G≈ 92 ± 24 Me. V Z(3930) DD M(DD) M = 3929± 5± 2 Me. V Gtot = 29± 10± 2 Me. V Nsig =64 ± 18 evts ± 11 evts PRL 100, 202001 PRL 94, 182002 (2005) PRL 96, 082003
Y(3940) confirmed by Ba. Bar B± K±w. J/ B 0 KSw. J/ ratio M(w. J/ ) PRL 101, 082001 Some discrepancy in M & G; general features agree
New Belle peak in gg w. J/ undetected l+ X J / w l- p+ p 0 p- undetected
M(p+p-p 0) vs M(l+l-) J/ l+l- M(p+p-p 0) Ge. V w p+p-p 0 • 4 trks ( 1 lepton, no kaons) • Sqi=0 • 1 p 0 select best one • veto ’ p+p-J/ • W<4. 3 Ge. V • Sp. T<0. 1 Ge. V • … M(l+l-) Ge. V
Sp. T vs W cut im in ar y M: 3914 3 2 Me. V, 7. 7 s G: 23 10 +2 -8 Me. V, Nres = 55 14 +2 -14 events pr el Signif. = 7. 7 ,
The 4 states near 3940 Mass(Ge. V) Range: (s(stat. )+s(sys. )) X(3940) Y(3940) Belle Z(3930) This X(3915) Good overlap with Ba. Bar “Y(3940)” values Width(Ge. V)
Se em s un lik el y Could it be the Z(3930)?
Ggg partial width +7 e. V (JP=0+) Ggg. B(w. J/ ) = 69 16 -18 P + Ggg. B(w. J/ ) = 21 4 +2 -5 e. V (J =2 ) For comparison: Z(3930): Ggg. B(DD) = 180 50± 30 e. V If X(3915) = Z(3930) = cc 2’ Bf(cc 2’ w. J/ ) Bf(cc 2’ DD) 0. 08 Huge for above-open-charm-threshold charmonium
cc assignments for X(3915), X(3940) & X(4160)? hc’’’ 4160 Me. V 3940 Me. V hc ” cc 0’ • Y(3915) = cco’? G(w. J/ ) too large? • X(3940) = hc”? mass too low? • X(4160) = hc’’’? mass way too low? 3915 Me. V
Y(4140) from CDF ar. Xiv: 0903. 2229 primary vertex Lxy secondary vertex B+ Vertex separation +- J/ Kai Yi’s talk in This session + - + Particle Identification (Kaon LLR) M: 4143. 0 2. 9 1. 2 Me. V, G: 11. 7 +8. 3 -5 ± 3. 7 Me. V, Nres = 14 5 events Signif. > 3. 8 M=m( + -K+K-)-m( + -)
comment on JPC of the X(3872)
JPC values from CDF & Belle §Fit to M(pp) favors L = 0 JPC = 1++ hep-ex/0505038 CDF: PRL 98 132002 PRL 96, 102002(2006) JPC = 1++ or 2 -+
Ba. Bar: X(3872) g. J/ & g ’ B+ K+g. J/ 3. 6 1++ g J/ or g ’ Allowed E 1 2 -+ g. J/ or g ’ Suppressed E 2 B+ K+g ’ M(g. J/ ) JPC = 1++ favored over 2 -+ 3. 5 NB: Molecular models have trouble with X(3872) g ’ Swanson PLB 598, 192 (2004) PRL 102, 132001 M(g ’)
Is there a cc assignment for X(3872) ? cc 1’ ? ? hc 2 ? ? 3872 Me. V • Mass is too low • especially if cc 0=3915 & cc 2=3930 • cc 1’ pp. J/ violates Ispin • Bf(X 3872 pp. J/ )>4% • G(g. J/ ) should be >>G(r. J/ ) • expt: G(g. J/ ) <<G(r. J/ ) • Mass is okay • hc 2 pp. J/ violates Ispin • Should be , , hc 2 pphc • G(g. J/ ) should be tiny • B Khc 2 is suppressed
the -1 Y states Y(4260) Ba. Bar e+e- g. ISRp+p-J/ Y(4350) & Y(4660) e+e- g. ISRp+p- ’ Ba. Bar Y(4008)? Belle M(p+p-J/ ) Ge. V at least 3, maybe 5 M(p+p- ’) Ge. V e+e- g. ISRLc. Lc Y(4630) Belle M(Lc. Lc)
Only 1 unassigned 1 -- cc level predicted measured
If not charmonium what else?
--many proposals- • L Maiani et al PRD 71, 014028 (2005) • T-W Chiu & TH Hsieh • NA Tornqvist PRD 73, 111503 (2006) • D Ebert et al PLB 590, 209 (2004) • ES Swanson … PLB 598, 197 (2004) PLB 634, 214 (2006) • E Braaten & T Kusunoki PRD 69 074005 (2004) • CY Wong PRC 69, 055202 (2004) • P Lacock et al (UKQCD) • MB Voloshin PLB 401, 308 (1997) PLB 579, 316 (2004) • SL Zhu • F Close & P Page PLB 578, 119 (2004) • X Liu … ar. Xiv 0708. . 4167 PLB 625, 212 (2005) _ cc-gluon hybrid • S Dubynski et al PLB 666, 344 (2008) • FK Guo et al PLB 665, 26 (2008) • DV Bugg ar. Xiv+0709. 1254 … PLB 628, 215 (2005) • E Kou, O Pene PLB 631, 164 (2005) Etc: • hadro-charmonium • threshold effects • … • FE Close, PR Page … c c modified charmonium • C Meng & KT Chao PRD 75, 114002 (2007) • W Dunwoodie & V Ziegler PRL 100 062006 (2008) • O Zhang, C Meng & HQ Zheng ar. Xiv: 0901. 1553 …
Model features D(*) molecules (real or virtual) masses should be near M(D(*))+M(D(*)) mass thresholds diquark-diantiquarks cc-gluon hybrids Expect SU(3) multiplets LQCD: M>~4. 3 Ge. V Etc. • hadro-charmonium • light hadron-charmonium bound states • threshold effects • … Open charm thresh =MD+MD** 4285 (above Y 4260 peak) Non-zero charges are not allowed
D(*) Molecules? masses should be near M(D(*))+M(D(*)) mass thresholds Favored model for the X(3872) Lots of literature on this, some very detailed (& some prior to the X(3872) discovery)
2 new measurements Belle X(3872) Mass -- in pp. J/ channel only -- Avg: PDG 08: CDF T. Kuhr @ QWG 08 MX(3872) = 3871. 5± 0. 2 Me. V MD 0+MD*0 = 3871. 8± 0. 4 Me. V
DD thresholds DSDS thresholds some of the states are near thresholds – notably M(X 3872) & M(D 0)+M(D*0) but this is not a universal feature
Hybrids? LQCD: M>~4. 3 Ge. V Open charm thresh =MD+MD** 4285 Me. V (above Y 4260 peak) Should be seen in open-charm channels above 4285 Me. V Non-zero charges are not allowed Favored assignment for the 1 -- Y states
DD** thresholds and the Y(4260), Y(4350) & Y(4660) D 4. 354. 26 - D 4. 28 - 3. 883. 85 - D DD Y(4350) & Y(4660) are well above all DD** thresholds & should have strong widths to DD*p D D 4285 4. 66 - Belle
No evidence for any 1 -- Y D**D σ(e+e–→open charm) via ISR PRD 77, 011103(2008) DD DDπ PRL 101 172001 (2008) Λc+Λc– PRL 98, 092001 (2007) D* D* Y(4660 ) PRL 100, 062001(2008) DD* (4415) Y(4260) (4040) Y(4008) (4160) Y(4350) ?
Almost all open-charm channels are accounted for (4040) ’s a v o l h ak P PM s ur h T Inclusive (BES) (Belle) Durham Data Base if Ruds=2. 285± 0. 03 k l a t Sexclusive Y(4660) (4415) *p D D . G in Y(4260) on s lt u s e r le l e B w Ne Y(4350) (4160) Y(4008) (3770) Belle: Sum of all measured exclusive contributions
These states have large G(pp. J/ ( ’)) eg: G(Y(4260) p+p- J/ ) > 1. 6 Me. V @ 90% CL X. H. Mo et al, PL B 640, 182 (2006) Much larger than measured charmonium widths: G( ’ p+p- J/ ) = 0. 104 ± 0. 004 Me. V G( ’’ p+p- J/ ) = 0. 044 ± 0. 008 Me. V
diquark-diantiquarks Expect SU(3) multiplets Isospin partners X-= d S=-1 partners Xs-= s doublet of “X(3872)” states M=8± 3 Me. V Maiani et al PRD 71, 014028
No multiplet partners seen Ba. Bar search for “X-(3872)” p-p 0 J/ PRD 71, 031501 B 0 B- X(3872)– M(J/ π–π0) Bf(B 0 K+X-)Bf(X- p-p 0 J/y) Bf(B- K+X 0)Bf(X 0 p+p-J/y) < 0. 4 (expect 2)
No evidence for X(3872) neutral partner X(3872)→J/ψπ+π– PRD 77, 111101, 2008 B+→XK+ 12. 8 8. 6σ B 0→XK 0 s BELLE-CONF-0849 2. 3σ MX = 2. 7± 1. 6± 0. 4 Me. V B 0→XK 0 s 5. 9 MX = 0. 2± 0. 9± 0. 3 Me. V M=8± 3 Me. V predicted Maiani et al PRD 71, 014028
Mass different in X DD* modes? “old” “new” 605 fb-1 D 0 g 414 fb-1 D 0 p 0 605 fb-1 D 0 p 0
Light-hadron charmonium bound states? cc My guess: masses should be near M(cc)+M(“narrow”-light-hadron) thresholds This would account for large decay widths to charmonium & the preference for some states to go to ’ & other J/ • S Dubynski et al PLB 666, 344 (2008) • FK Guo et al PLB 665, 26 (2008) charmonium +excited light hadrons charmonium + gnd-state light hadrons
Charmonium + (narrow) light hadron thresholds
Scorecard • D(*) Molecules – favored for the X(3872) – but many XY states are not near thresholds • hybrids – no sign of open charm decays • diquarks-diantiquarks – No sign of SU(2)/SU(3) multiplet partners • Light-hadron charmonium bound states – not much coincidence between states & thresholds
Candidates for XY counterparts in the b- and s-quark sectors
Y(4260) equivalent with b-quarks? Belle (e+e- p+p- (n. S)) _ Peaks not consistent with known bb states K. F. Chen et al (Belle) ar. Xiv: 0808. 2445 G(pp (n. S)) ~ 1000 x too large for conventional bottomonium
Y(4260) equivalent with s-quarks? e+e- g f 0(980)f (e+e- p+p- f(1020)) Y(2175) f 0(980)f Ba. Bar f 0(980) p+p- M(f 0(980)f) Ba. Bar, PRD 74, 091103
Confirmed by BES & Belle confirmed by BESII in J/ h f f 0(980) (e+e- f 0(980)f(1020)) BES Belle M(f 0(980)f Ge. V C. P. Shen et al (Belle) ar. Xiv: 0808. 0006 M. Ablikim et al (BES) PRL 100, 102003 (2008) NB: Radial excitation of the f is not ruled out
Do the X & Y mesons have electrically charged counterparts?
The Z+ meson candidates Z(4430)+ M(p± ’) Ge. V 6. 5 M 2(p± ’) Ge. V 2 B K p+ ’ t x e n on i s es s c 1) Ge. V 2 M 2(p±c’ Z 1(4050)+ M(p±cc 1) Ge. V he t Not confirmed by in i n Ba. Bar ar. Xiv: 0811. 0564 ga i r at P. C 142001 S. -K. Choi et al (Belle) PRl 100, M 2(Kp’) Ge. V 2 & ov +c t s i B K p h c 1. C R y >6 b d e s cus + Z 2 is (4250) D M 2(Kp’) Ge. V 2 R. Mizuk, R. Chistov et al (Belle) PRD 78, 072004
Concluding remarks _ • Lots of non-qq mesons candidates are seen _ • No single non-qq model explains them well • Recurring theme: large widths for decays to final states with charmonium
Winston Churchill & vwomen Men occasionally stumble over thecharm, truth, but most of them pick themselves up and hurry off as if nothing ever happened. Puzzles often New insights
Thank you
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