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Scalar mesons in VES experiment

Scalar mesons in VES experiment. Outlook. Introductory remarks VES Experiment Scalars at VES – various topics Conclusions. Why to study scalars. NOTE ON SCALAR MESONS by C. Amsler , T. Gutsche , S . Spanier and N.A.T¨ornqvist (in RPP 2011):

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Scalar mesons in VES experiment

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  1. Scalar mesons in VES experiment Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  2. Outlook • Introductory remarks • VES Experiment • Scalars at VES – various topics • Conclusions Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  3. Why to study scalars NOTE ON SCALAR MESONS by C. Amsler, T. Gutsche, S. Spanierand N.A.T¨ornqvist (in RPP 2011): • quantum numbers of the vacuum (JPC = 0++) • can condense into the vacuum and break a symmetry such as a global chiralU(Nf )L× U(Nf)R • How they break ? Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  4. Experimental approaches and evidences • Numerous and various • OPE scattering π/K N  N π/K π, N K/π K • Diffractive π N  NPPP • p p̅  PPP(at rest & in flight) • γ γ PP • D(*)/ B PPPDalitz plot • J/ψ K* K π • τ K π ν • φ [a0(980) + f0(980)] γ • ….. • In general: mostly PP – S wave Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  5. VES setup • secondary (mostly π-) beam of U-70, p ~ 25 – 45 ГэВ/с • magnetic spectrometer pt = 0.5 - 0.7 GeV/с • EM – calorimetry • K/π – identification (4-18 GeV/с) • Fast DAQ (104/spill) • Minimum bias trigger 1 - target; 2 - veto counters; 3 - multiplicity discriminator; 4 -magnet ; 5 - Čh detector; 6 –Sci–hodoscope; 7 - Ecal Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  6. Experimental studies of scalars with VES • Form-factor of the decay ηʹ → ηππ • The (ωφ) in Charge Exchange Reaction • ISB decay f1(1285)  3 π • Search for ISB decay π(1800)  ηππ Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  7. Form-factors in the decaysηʹ → ηππ • The width and spectral shape of the ηʹ → ηππ are of interest for various aspects • General tool: ChPT (expansion in p2, mu,d,s, 1/Nc in Nc  approach) • + FSI (heavy ηʹ) • intermediate Resonances in play • encoded in LEC (@low s) • introduced “by hands” or dynamically • Mainly with JPC = 0++ (coupling to 1- suppressed in I=0 P  PPP due to G-parity) Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  8. ηʹ → ηπ+π- DP with VES • Measured in • diffractive associative production ηʹ π- • Charge exchange reaction • largest sample at the moment (~23 k ev) • more general DP parameterization: |M|2 1 + a  Y + b  Y 2 + c  X + d  X2 + … (1) Compared w. “linear” one ( complex) |M|2 |1 +   Y| 2 + c  X + d  X2 (2) (1) & (2) equivalent ONLY for b > a2/4  0 Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  9. VES Dalitz plot Y – dependence of Dalitz plot distribution for 8 slices on X. Data (points) and fitting function (line) Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  10. ηʹ → ηπ+π- DP with VES (cont’d) • The parameter сcompatible with zero as expected from C – symmetry • The b NEGATIVE  the “linear” parameterization not adequate • The large and NEGATIVE d impacts models Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  11. ηʹ → ηππ DP: Experiment vs. Theory • PL B651 22 (2007) (VES) [26] B.Borasoy and R.Nissler, EPJ A26, 383 (2005) • PAN 72 231 (2009) (GAMS) (neutral mode; may differ) • PR D 83, 012003 (2011) (BESIII) - New (~44 k ev) JHEP 1105:094,2011 RafelEscribano, PereMasjuan, Juan Jose Sanz-Cillero Large-NcChPT vs. RChT Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  12. Scalars in ηʹ → ηππ DP • a0(980) contribution dominant •  is essential • But … heavier tensor states are not negligible • Accounting for other states required to study scalers Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  13. Scalar in (ωφ) system in charge-exchange (OPE compatible) reaction Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  14. X(1812): Earlier observation in J/ψ(γωφ) By BESII Collab. ( Ablikim et al.), Phys. Rev.Lett.96:162002,2006 Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  15. PWA of (ωφ) system (Hadron-2009, Proceedings of XIII International Conference) Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  16. PWA of (ωω) system Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  17. N(ωφ)/N(ωω) ratiofor JP=0+ Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  18. OZI rule in 0+ & 2+ N0+() /N0+ () = 0.65  0.10 (1.82 GeV < M < 2.0 GeV) • The violation of the OZI rule in decays of scalar resonances is expected in many models “On the origin of the OZI rule in QCD”, Nathan Isgur , H.B. Thacker Phys.Rev. D64 094507, 2001 ……. Compare with 2+ N2+() /N2+ () = 0.045  0.010 Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  19. ISB Decay f1(1285)π+π-π0 • IGJPC = 0+1++ M = 1282 MeV,  = 24 MeV • Dominant channels : KKπ, ηππ(incl. a0(980)π),4π • Decay to 3π violates Isospin Symmetry Possible mechanisms - f1(1285)  a1(1260) mixing(a la ω ρ, η π, Δ  N, Σ  Λ) - «contact» f1 3π - Intermediate scalars mixing: f1π a0  π f0 3π (possibly) enhanced through KK- loops (Achasov, Devyanin, Shestakov PL B88, 1979) Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  20. Experimental findings • 1-st report @Meson-2008 (Cracow) • Final publication EPJ A (2011) 47: 68 • Associative f1π- production • π- A  A f1π- M(ηπ+π-) in η3π f1(1285) Effect of angular weighting 1+ (0+ 0- ) P on M(π+π- ) M(π+π- ) for M(3 π) within f1(1285) mass region Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  21. Experimental result Estimates within “Achasov’ model” varying a0/f0 parameters BR(f1π+π-π0) / BR(f1ηπ+π- ) ~ 0.05 – 0.5 % VES result exceeds maximal (with extreme f0(980)-KK coupling) More: accounting for lower 2-mass tail Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  22. Comparison w. BES-III VES BES-III arxiv/1012.1377v1.pdf Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  23. Possible (another) mechanism? • FSI (re - scattering) expected -- small @ BES as a0(f0) and  well separated -- large @ VES as all products “confined” • An example: Triangle Singularity (TS) ISB (1405/1475) f0arXiv:1108.3772v1 Jia-Jun Wu et al. TS a0 f0 mixing f1(1285) f1(1285) • JP = 1+ vs. 0- other TS character • f1(1285) light  loop particles off-shell Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  24. Search for ISB π(1800)  ηππ • Assuming a0 (980)  f0 (980) mixing • major JP=0-π(1800)  f0(980) π a0 π ηππ • Rich source: diffractive π- N → N π-(1800) with π-(1800) → (ηπ0) π- • 3-particles final state compared w. f1π case • but: broad (>120 MeV) π(1800) compared w. narrow (~25 MeV) f1(1285) • Specific feature (PWA needed): 0-(1800)→ 0+(ηπ) π M(0+)~0.98 ГэВ neutral only Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  25. Experimental observations π- N → N ηπ0 π- with  → +-0 for π(1800) region 1.72 < M(ηπ0 π- )< 1.92 GeV M(ηπ0) - left M(ηπ-) - right Signal compatible w. a0(980): N(a00 ) 600 60 N(a0- ) 130 60 Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  26. PWA of (+-0)0- •  → +-0 with final experimental width • Very large (combinatorial) background • 5–particles PWA (includes ω(782) → +-0 and bckg.) • Many isobars ρ(770), a2(1320), a1(1260), b1(1235), a0(980) • 24 waves (JPC=0--, 0-+,1+-,1--,1++,2-+,2++,…) • Different production mechanisms (exchanges) (OPE, ω, diffraction) → t - dependencies • Separate waves w. (not symmetric) a00 and a0- • Model dependent a0 (980)  f0 (980) “mixing” signal • JP = 0- for π(1800)  “a00” - Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  27. Some (large) waves (preliminary) 2++ωρ 0- →“a00” - 0-+ a1ρ Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  28. Preliminary result @ 90% CL N.B.: π(1800)  K*K => no TS – like enhancement • Analyses π- N → N π-(1800) → (ηπ0) π- → () () π- desired • much less bckg lower noise; less states; (relatively) larger signal • pilot VES run (2010) with 1-track final state: promising • full run planned for November 2011 Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  29. Conclusions • Specific shape of Dalitz plot for ηʹ → ηπ+π- adopted with RChT; scalarsAND tensors contribute • Scalar near threshold in ω(782) (1020) compatible w. X(1812) by BESII strongly violates OZI rule • ISB–decay f1(1285)π+π-π0 incompatible with “KK-loop mixing” of a0 (980)  f0 (980) alone: too intensive and structured • An indication to ISB–decay π(1800)  ηππ through “a0 (980)” needs more analyses Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  30. Backup slidesηʹ → ηπ+π- by VES in BES interpretation Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  31. Backup slidesRChT vs. large-NcChPT Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  32. Backup slides waves for PWA of (ωω) • 1 - (0++)0- JLS=000 11 - (0-+)0+ JLS=011 • 2 - (2++)0- JLS=202 12 - (2-+)0+ JLS=211 • 3 - (2++)0- JLS=220 13 - (1++)0+ JLS=122 • 4 - (2++)0- JLS=222 14 - (3++)0- JLS=322 • 5 - (2++)1- JLS=202 15 - (2++)1+ JLS=202 • 6 - (4++)0- JLS=422 16 - (4++)1+ JLS=422 • 7 - (4++)0- JLS=440 17 - FLAT • 8 - (4++)0- JLS=442 • 9 - (4++)0- JLS=422 • 10 - (6++)0- JLS=642 Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  33. Backup slides K*K* rescattering vs. () resonance arXiv:1107.0781v1 Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  34. Backup slides X(1812) search @ BELLE • X(1812) search @ BELLE in B+  K+ (ω) - no signal (arXiv:0902.4757v2) Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  35. Backup slides(1405) f0(980)0 @BESIII Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

  36. Backup slidesM(π+π- ) in (1440) →  w. TS Yu.Khokhlov (IHEP Protvino) for VES PhiPsi11 Novosibirsk, 19.09.2011

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