Exotic Hadrons with Heavy Quarks Experimental Perspective Tomasz

Exotic Hadrons with Heavy Quarks: Experimental Perspective Tomasz Skwarnicki Syracuse University, NY, USA

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 2 My connection to Dubna • My mentor during Ph. D. research (Crystal Ball experiment at DESY) Bogdan Niczyporuk 1936 -2017 M. Curie - Sklodowska University, Lublin, 1956 -58; M. S. , Moscow University 1962; Ph. D. , Jagiellonian University, Krakow, 1973; Dr. hab. Institute of Nuclear Physics, Krakow, 1983. Research physicist, JINR, Dubna, 1963 -73; Adjunct, Institute of Nuclear Physics, Cracow, 1973 -83; Visiting Prof. , Stanford University (CA), 1983 -88; Senior physicist, CEBAF (JLab) 1988 -2003.

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 3 From particle zoo to Quark Model Strangely long-lived states gave us clues about the right underlying symmetries: Quarks and flavor independence of strong interactions 1950 -ies K, L, … N(1440) D n p a 1 h(1295) …W b 1 h N(1650) D(1600) r p h 1 W- 1964 h’ Quark Model Still investigating! QCD (came later)

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 4 QCD and QCD motivated states q=u, d, s, c, b, t Asymptotic freedom SU(3)color Asymptotic freedom Hadron sizes Confinement V~ r … A large number of hadronic states expected from radial and angular momentum excitations. V(r) We are still looking for these! V~1/r Static qq potential in Lattice QCD 0. 5 1/10 1 1/0. 4 We have to rely on data and QCDmotivated phenomenology when trying to understand more complex hadronic structures. 1. 0 [fm] 1/0. 2 [1/Ge. V] Unlike in QED, large fine and hyperfine structures for lower excitations.

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 5 Mesons from quarks & antiquarks in QCD color octet color triplet 3 color antitriplet _ 3 quark antiquark q q Color flux tube stretched between quark and antiquark with attractive potential color singlet 1 8 attractive color force (qq) meson e. g. K+ _ s u repulsive color force quarks will pull apart _in any octet configuration gluons happen to belong to the color octet

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 6 (Colored) diquarks in QCD color sextet (symmetric) (antisymmetric) color antitriplet color triplet 3 quark q color triplet _ 3 3 6 quark q repulsive color force attractive color force _ quarks will pull apart in any sextet configuration (perturbatively: half as strong as in the meson) (qq) diquark s u Not a particle, just a building block in QCD Diquark can go in a place of antiquark in a hadron; antidiquark in place of quark.

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 7 Hadrons from diquarks? Still an open question! Role of diquarks in building hadrons? vs. Light and heavy baryon spectroscopy is sensitive to this question Additional motivation for existence of tetra- and penta-quarks. Does effective mechanism to suppress rapid fall-apart exist?

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 8 Tetraquarks (pentaquarks) vs meson-meson (meson-baryon) molecules • The same quark content can, in principle, create a meson-meson molecule or a tetraquark • However, mass spectrum from these two types of bindings are very different ((qq)) tetraquark (qq)-(qq) meson-meson molecule _ u d _ _ u u _ u d s V(r) We don’t know if either one exist (“exotic hadron”) Very rich mass and JP spectrum expected! … However, states can be undetectable if extremely broad. r s Typically expect only one state n=1, L=0. Fall apart prevented by spatial separation – long-lived states if below threshold. Mass and JP fairly constrained from the constituents.

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 9 Hadron spectroscopy and heavy flavors K*, y’’, ¡’’’ J Log-scale! November revolution of 1974 s, c, b q K, D, B s, c, b q , D, B q, c, b (q=u or d) wide e+e- → hadrons y c, b p. Be → e+e- X 13 S 1 Long-lived and non-relativistic! 23 S 1 ®g 13 P (at SPEAR) 2, 1, 0 narrow PRL 119 (2017) 221801 13 P 2, 1, 0 ®g 13 S 1 13 P 1, 2 ® m+m-13 S 1 PRD 34 (1986) 711 q q q Eg [Me. V]

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 10 Hadron spectroscopy and heavy flavors Belle 2003 J Log-scale! November revolution of 1974 p. Be → e+e- X e+e- → hadrons y or ? DD* DD very narrow GX(3872) <1. 2 Me. V not all mesons are simple!

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 11 Hadron spectroscopy and heavy flavors Belle 2003 J Log-scale! November revolution of 1974 p. Be → e+e- X e+e- → hadrons y LHCb 2015 or ? DD* DD very narrow GX(3872) <1. 2 Me. V Pc(4450)+ Pc(4380)+ not all mesons are simple! neither are all baryons

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 12 New particle zoo: charmonium above flavor threshold Old narrative (before 2003) predicted measured Figures from Olsen, Skwarnicki, Zieminska Rev. Mod. Phys. 90, 015003 (2018); ar. Xiv: 1708. 04012

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 13 New particle zoo: charmonium above flavor threshold (mostly a freak show) Old narrative (before 2003) predicted measured Figures from Olsen, Skwarnicki, Zieminska Rev. Mod. Phys. 90, 015003 (2018); ar. Xiv: 1708. 04012 New narrative

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 14 Mass near D 0 D*0 threshold _ u c _ c u D 0 D*0 Dual nature of X(3872) Run I 3 fb-1 Known decay rates: Charmonium-like prompt production rates _ c c ALICE, PL, B 754, 360(2016) PR, C 93, 029917(2016) Enhanced isospin violating decays LHCb-PAPER-2015 -015 Run I 3 fb-1 ATLAS JHEP 01, 717(2017) A. Esposito et al. PRD 92, 034028 (2015) (ATLAS data inserted by S. Olsen) 0 -1 - interacting in S-wave compatible with JPC=1++ only small admixture of D+ D* ar. Xiv: 1711. 10626 Charmonium-like pattern of radiative decays LHCb molecular unlike a features molecule LHCb-PAPER-2014 -008

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 15 Lessons from X(3872) •

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 16 X(3872), so far, is unique! • predicted measured

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 17 Near-threshold states: Zb+, 0 and Zc+, 0 states 5 Mass Me. V BES-III Zb(10650) Zb(10610) Y(4260) B*B* BB 4200 Zc(4020) (3 S) D*D* Zc(3900) Belle (2 S) 10, 650 Me. V M( (n. S)π+)max 3800 21 S 10, 610 Me. V 23 S 1 0 DD* 13 P 11 P DD 0, 1, 2 1 3400 (1 S) 13 S 1 3000 • Zc(4020) 11 S 0 BES-III and Belle _q _ Q q

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 18 Anomalous charmonium-like vector states 13 D 1 33 S 1 23 D 1 43 S 1 Hadron Spectrum Collaboration (LQCD m =240 Me. V) JHEP 1612, 089 (2016) • Hybrid-charmonium same? cc ? _ c – Masses not too far from the predicted 1 - - hybrid (n=1, L=0) hybrid by the lattice QCD: y(4415) Y(4360) Dai et al. , PRD 96, 116001 (2017) Y(4260) y(4160) y(4020) y(3770) • Only one 1 - - hybrid expected in this mass range • y(4020), y(4160), y(4415) not well reproduced by lattice – Gee suppressed by a spin-flip needed to produce cc in S=0 configuration – y can proceed via DD** rescattering – However, expected to decay to DD(*) , but not observed [CLEO-c PR D 80, 072001(2009)] F. Close, P. Page PL B 628, 215 (2005) E. Kou, O. Pene, PL B 631, 164 (2005) S-L. Zhu, PL B 625, 212 (2005) P. Guo, A. Szczepaniak G. Galata, A. Vassallo, E. Santopinto PRD 78, 056003 (2008) …

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 19 Anomalous charmonium-like vector states 13 D 1 33 S 1 23 D 1 43 S 1 _ _q c D 1 _ c q D same? Asymmetric shape: M. Cleven, Q. Wang, F. K. Guo, C. Hanhart, U-G. Meißner, Q. Zhao, PRD 90 (2014) 074039 _ _ q c Dai et al. , PRD 96, 116001 (2017) q c • Tetraquark (diaquarkonium) L. Maiani, F. Piccinini, A. Polosa, V. Riquer, PR D 89, 114010 (2014): – Tetraquark transitions: Y(4260) Zc(3900) , Y(4260) X(3872)g (possibly observed by BESIII)

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 20 Anomalous charmonium-like vector states 13 D 1 33 S 1 23 D 1 43 S 1 same? Dai et al. , PRD 96, 116001 (2017) G. C. Rossi, G. Veneziano, NP B 123, 507 (1977)!

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki Anomalous behavior of 1 -- states above open bottom threshold _ bb 21 (5 S) (6 S) hb(1 P) + – (1 S) + – hb(2 P) + – (2 S) + – PRL 117, 142001(2016) PRD 93, 011101(2016) e+e– (1 S, 2 S, 3 S) + – and hb(1 P, 2 P) + – proceed via (5 S), (6 S) Unlike in charmonium! (3 S) + – However, (5 S), (6 S) (1 S, 2 S, 3 S) + – widths are 100 larger than (3 S), (2 S) (1 S) + – OZI-rule violation Also widths for (5 S), (6 S) hb(1 P), hb(2 P) + – are comparable, but require heavy quark spin flip HQSS violation Like in charmonium!

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 22 Charged charmonium-like states in B decays Breit-Wigner amplitude 4344 4411 4541 JP=1+ GZ(4430)=181± 31 Me. V JP=1+ GD(2600)=104± 20 Me. V 4605 4475 4277 Me. V JP=? No clear explanations. Ø Too broad to be molecular bound states? Ø No tetraquark model can accommodate all of them. Ø Rescattering effects? Ø Artifacts of complicated amplitude analyses?

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 23 Many other strange animals with no clear interpretation _ c c LHCb PRL 118, 022003 (2017) PRD 95, 012002 (2017) Thomas Britton, Ph. D, Syracuse. 2016 https: //surface. syr. edu/etd/510/ _ _ s c 1++ X(4700) X(4500) 0++ S c X(4700) ++ No h-exchange 0 +69± 26 Me. V Ds 0+Ds 0*Plenty of other thresholds, but no matching JPC numbers 1++ X(4274) X(4140) (some seen also by CDF, D 0, CMS) _ _s c _ c s No -exchange forces! h-exchange OK Ds+Ds*- +66± 5 Me. V X(4500) 0++ X(4274) 1++ X(4140) 1++ Postdiction by L. Maiani, A. D. Polosa, V. Riquer PRD 94, 054026 (2016) Possibly radially excited 0++ tetraquarks. However, only one 1++ state with color triplet diquarks. F. Stancu, J. Phys. G 37, 075017 (2010) Predicted two 1++ tetraquarks in this mass range (S=0, 1 diquarks in color triplet and sextet)

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki Many other strange animals+ with no clear interpretation Sc LHCb PRL 115, 072001 (2015) Molecules d c Nathan Jurik. Ph. D Syracuse 2016 https: //surface. syr. edu/etd/640/ u Tightly-bound penatquark u c _ c d u _ u c D*0 Karliner, Rosner PRL 115, 122001(2015) and others + *0 p cc 1 Sc D +1± 3 Me. V p d u u u _ c c JP=? cc 1 p J/y Pc(4450)+ - 10± 3 Me. V Pc(4380)+ is too broad to be a molecule Pc(4380)+ or JP “preferred” rather than definitely determined Maiani et al PLB 749, 289 (2015) and many others Such mass difference and the opposite parity can be explained by DL=1 and DS=1 However, where all the expected other excitations ? Realistic rescattering mechanisms (cusps, triangle anomalies) have the same JP selection rules as realistic molecular models (must happen in S-wave)

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 25 Rethinking of light hadron spectroscopy? Above multiquark-threshold S States may be “missing” for a good reason (25 k, we now have 220 k, many other channels…)

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 26 Plenty of evidence for diquarks in heavy baryons (example) Spin of charm quark decouples because of its heavy mass: good place to study ss quark pairs: s _ u s s c s s q c LHCb PRL 118, 182001 (2017). Wc** 0 Xc+K- (Strong decay) The narrow states observed by LHCb are likely 1 P and 2 S of c-(ss diaquark) Wc(3000) Wc(3050) G<1. 2 Me. V Wc(3066) G=3. 5± 0. 4 Me. V G=8. 7± 1. 3 Me. V Wc(3090) G<2. 6 Me. V Wc(3119) _u s Xc+ sidebands c narrow G=4. 5± 0. 7 Me. V Wc** 0 OZI allowed but rips the diquark apart _ q Wc** 0 c Wc(3188) ? G=60± 19 Me. V the diquark survives wide

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 27 Doubly-flavored tetraquarks baryon c u tetraquark Replace the light quark with light anti-diquark in color triplet configuration d b c b LHCb PRL 119, 112001 (2017) Lc+ p. K- + 1. 7 fb-1 the same toolkit New holy grail of heavy quark spectroscopy LHCb-PAPER-2017 -018 Karliner, Rosner PRD 90, 094007 (2014) Distance from EM or strong decay threshold (Me. V) Part of Run II u Luciano Maiani _ _ b b d u The lightest 1+ state 0+ state ? 1+ state Stable tetraquark, will decay weakly Karliner, Rosner PRL 119, 202001 (2017) See also: Eighten, Quigg PRL 119, 202002 (2017); Czarnecki, Leng, Voloshin PL B 778, 233 (2018) Esposito, Papinutto, Pilloni, Polosa, et al PRD 88, 054029 (2013); and others Consistent results predicted by LQCD: Francis, Hudspith, Lewis, Maltman PRL 1118, 142001 (2017)

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 28 Observation of double Y production at LHC JHEP 05 (2017) 013 •

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 29 Super. KEKB Super Tau-Charm Factory (STCF) Proposed at Beijing and Novosibirsk 2020 2030

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 30 Colliders and bb rates Past and future: experiments producing b-hadrons 103 LHCb Phase-II Upgrade Belle II 102 Belle 101 100 Ba. Bar hadron colliders LS 5 LS 3 Tevatron CDF, D 0 LHCb Phase-I Upgrade 10 Ge. V e+e- colliders 104 LHCb LS 4 105 LS 2 106 HL-LHC CMS ATLAS LS 1 (within the angular acceptance) bb pairs produced (s-1) 107 now Upgraded LHCb CMS Good hadron ID, dedicated large-bandwidth triggers, Enormous rates of b-mesons and b-baryons Belle II 2000 2005 2010 2015 2020 2025 2030 2035 ATLAS CDF 10 fb-1 , D 0 8 fb-1 LHCb ATLAS, CMS Run III Run IV Run V+VI 3 fb-1 50 fb-1 300 fb-1 25 fb-1 450 fb-1 3000 fb-1 7 -8 Te. V 13 Te. V 14 Te. V (27 Te. V HE-LHC? ) Higher luminosities than LHCb. No hadron ID. Limited triggers. Good hadron ID, good detection of neutrals. Good absolute reconstruction efficiencies.

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki 31 Future: photo-production of Pc states at JLab Glue. X preliminary E 12 -16 -007 will run in Spring 2019 CLAS 12

Exotic Hadrons, Dubna, Sep. 18, 2018 Tomasz Skwarnicki Conclusion • 32