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What are good building blocks of Hadrons?

Charmed Baryon Production (Charmed baryon Spectroscopy via p ( p - , D * - ) Y c ) 11 Sep., 2013 H. Noumi RCNP, Osaka University. What are good building blocks of Hadrons?. Constituent Quark. [ qq ]. ͞ q. ͞ q. q. q. q. q. q. q. hadron (colorless cluster). q. q. q. Diquark ?.

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What are good building blocks of Hadrons?

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  1. Charmed Baryon Production(Charmed baryon Spectroscopy via p(p-,D*-)Yc)11 Sep., 2013H. NoumiRCNP, Osaka University

  2. What aregood building blocks of Hadrons? Constituent Quark [qq] ͞q ͞q q q q q q q hadron (colorless cluster) q q q Diquark? (Colored cluster)

  3. How to form baryons? • Most fundamental question • Interaction btwn quarks Diquark correlations q q q • 3 [qq]-pairs in a Light Baryon How to close up diquark correlations

  4. Charmed Baryon VCMI～[as/(mimj)]*(li,lj)(si,sj) • Weak CMI with a heavy Quark • [qq] is well Isolated and developed qq • Level structure of Yc* • Decay Width/Decay Branching Ratios, etc. Q

  5. Charmed Baryon Spectroscopy (P50) Missing Mass Spectroscopy Measure D*- Missing Mass Spectrum Dispersive Focal Plane Hydrogen Target K+ 20 GeV/c p-Beam p- p- High-resolution, High-momentum Beam Line D*-Spectrometer

  6. Charmed baryon spectrometer 2m Modified design FMcyclotron magnet J-PARC E16 ⇒ 2.3Tm, 1 m gap • High ratedetectors • Fiber, SSD • Large detectors • Internal detectors • DC, RPC • PID: RICH • Hybrid radiator Ring Image Cherenkov Counter Internal TOF FM magnet ps- Internal DC LH2-target p- Beam GC Beam p- SSD K+ Fiber tracker TOF wall Decay p+ DC Internal TOF • Large acceptance multi-particle spectrometer system • Multi propose spectrometer

  7. Background reduction 3 ＊ D* tagging: > 106reduction ⇒Other event selection • Forward scattering angle cut ⇒ Reduction (2.2-3.4 GeV/c2) = 15 • Signal acceptance = 0.54 • 1900 → 1000 counts 15×2.0×106reduction background W/ signals Reduction qpD* qD0 qD0ps qps S/N qKp Kpqcm

  8. Background spectrum Only D* tagging W/ event selection Clear peak structure @ 1 nb/peak case ＊Main background structure is dominant. ⇒ Achievable sensitivity: 0.1-0.2 nb (3s level, G < 100 MeV) W/o signal W/o signal Sum Main BG (s-production + Miss-PID) Associated charm production BG W/ signal: 1000 counts/peak W/ signal: 1900 counts/peak

  9. Decay measurement Internal tracker • Method: Mainly Forward scattering due Lorentz boost (q<40°) • Horizontal direction: Internal tracker and Surrounding TOF wall • Vertical direction: Internal tracker and Pole PAD TOF detector • Mass resolution: ~ 10 MeV(rms) • Only internal detector tracking at the target downstream • PID requirement: TOF time difference (p & K) ⇒ DT > 500 ps • Decay particle has slow momentum: < 1.0 GeV/c Magnet pole Target Beam Beam Target Magnet pole Pole PAD TOF wall Surrounding TOF wall

  10. Basic performances Acceptance: D*- detection • Acceptance • 50-60% • exp(bt) (t-channel, b = 2 GeV-2) • Yield @ 1 nb case: ~1900 counts • 4 g/cm2LH2 target, 8.64×1013p- (100 days) • eall= 0.55 • Acceptance for decay particles: ~85% • Lc(2940)+→ Sc(2455)0 + p+ • Lc(2940)+→ p + D0 ＊Compare coverage cosq> -0.5 • Resolution • Dp/p = 0.2% @ 5 GeV/c • Invariant massresolution • D0: 5.5 MeV • Q-Value: 0.7 MeV • Missing massresolution • Lc+: 16.0 MeV • Lc(2880)+: 9.0 MeV • Decay measurement • DM ~10 MeV exp(bt) Isotropic in CM Decay angle: Lc(2940)+→ Sc(2455)0 + p+ Forward direction (Beam direction)

  11. Tagged missing mass spectra Sc0 p+ Sc++ p- SUM Sc0 ＊Full event w/ background @ 1 nb • Continuum background around the peak region • Signal counts • Scp mode:~230 counts • p D mode: ~320 counts Sc++ Signal Main BG Lc+ p+ p- p D0 D0 Lc+

  12. Tagged missing mass spectra Sc0 p+ Sc++ p- SUM Sc0 ＊Full event w/ background @ 1 nb • Selecting Lc+p+p- decay chain ⇒ Background level was drastically decreased. • Signal counts • Scp mode:~230 counts⇒ ~200 counts • p D mode: ~320 counts Sc++ Signal Main BG Lc+ p+ p- p D0 D0 Lc+

  13. What We can Learn from P50… • Production Cross Section Not only for feasibility but also… • Production Mechanism (Hosaka-san) • Does the Regge model work? (large s & small |t|) • Coupling Constant/Form Factor -> LQCD? • What does the state population tell us? • Spin/Isospin Structure • Wave Functions (Q-Diq picture or others) • So-called rho-mode (di-quark) excitation? • Application of pQCD (Kawamura-san) • Applicable at large s &|t| (Hard process)? • Prediction from pQCD • Are there any feedback from the P50 measurement?

  14. What We can Learn from P50… • Expected Spectrum • Excitation Energy and Width • Baryon Structure • Can we see a Quark-diquark picture? • Decay Property • Decay branch/partial width • Baryon Structure • G(Yc* -> pD)/G(Yc* -> pSc) ? • Angular Distribution • Spin/Parity

  15. Charm production Cross Section • No exp. data for the p(p-,D*-)Lc is available but σ<7nb at pp=13 GeV/c at BNL (1985)

  16. Charm production Cross Section • Photoprod. of LcD*barXon p at Eg=20 GeV. • s(LcDbarX) =44±7+11-8nb • s(D-X)=29±5+7-5nb • s(D*-X)=12±2+3-2nb s(LcD*barX) ~ 18nb • This seems sizable. g D* p LC , X Abe et al., PRD33, 1(1986)

  17. Charm production Cross Section • s(pN→J/ψX) =（1±0.6）nb and (3.1±0.6)nb at 16 GeV/c and 22 GeV/c. • OZI-suppressed process! LeBritton et al., PLB81, 401(1979) J/ψ p N X

  18. Comparison in strange sector • OZI-suppressed process in Strange Sector • s(p-p→fn) =（1.66±0.32）nb at 4 GeV/c. • s(p+p→fp+p) =（9.5±2.0）nb at 3.75 GeV/c -> s(pN→fN)/s(pN→fX)~1/10? • OZI-non-suppressed process • s(p-p→K*L) =（53±2）nb at 4.5 GeV/c -> s(p-p→K*L)/s(pN→fX)~2? -> ??? s(p-p→D*Lc)/s(pN→J/yX)~2? Avres et al., PRL32, 1463(1973) Gidalet al., PRD17, 1256(1978) Crennell et al., PRD6, 1220(1972)

  19. Comparison in strange sector s(mb) s∝s-a s/s0

  20. Theoretical Estimations • t-channel PS meson exchange • Comment on the pQCD model • Regge Model: revisit

  21. discussedwith A. Hosaka Revisit the Regge Theory • shows the typical s-dependence of binary reaction cross sections at the large s region; • Regge trajectory: • scale parameter s0 : s at the threshold energy of the reaction AB → CD (*In Kaidalov’s Model: s02(aD*(0)-1)=sCDar(0)-1 *sCDaJ/y(0)-1 sAB=(Σmi)A*(Σmj’)B, mi:transversal masses of the consituent quark) • Treatment of G(-a(t)) to avoid possible singularities • Actually introduce phenomenological form factor • G(-a(t)) →G(-a(t0)): naïve Regge • → G(1-a(t0)) : Kaidalov’sRegge[Z. Phys. C12, 63(1982)] • → exp(R2t): Grishina’sRegge[EPJ A25, 141(2005)]

  22. calculated by A. Hosaka Regge Theory • PS(K,D)-Regge (Top): s/c-prod: ~10-5(Naïve), ~3x10-5(Kaidalov) • V(K*,D*)-Regge (Bottom): s/c-prod.: ~10-4(Naïve), ~3x10-5(Kaidalov) Scale Parameter s (arb.) pp=20 GeV/c pp=20 GeV/c s/s0 s/s0 Regge Trajectory s (arb.) pp=20 GeV/c pp=20 GeV/c s/s0 s/s0

  23. Regge Theory • Normalization with s(p(p-,K*)L) data [PR163, 1377(1967), PRD6, 1220(1972)] • Naïve Regge shows a steeper s-dependence • Grishina’sRegge with R2=2.13 GeV-2 reproduces data well. • Charm production: ~10-4 of strangeness production, 　　　→　We expect s (p(p-,D*)Lc) close to 10nbat pp=20 GeV/c. p(p-,K*)L Ratio of s- to c-prod. exp(R2t) s (mb/sr) exp(R2t) G(-a(t0)) s(p(p-,K*)L)/ s(p(p-,D*)Lc) p(p-,D*)Lc exp(R2t) G(-a(t0)) G(-a(t0)) s/s0 s/s0 pp=20 GeV/c pp=20 GeV/c

  24. Comment on the Coupling Constant • Comparison of gD*D*p/gK*K*pandgLcND/gLNK* • Estimated by means of the Light Cone QCD Sum Rule • Exp. Data • Taking gD*D*p/gK*K*p~1, gLcND*/gLNK*~0.67 　　　　　→　We expect s (p(p-,D*)Lc) ~a fewnb. M.E. Bracco et al. Prog. Part Nucl. Phys. 67, 1019(2012) A. Khodjamirian et al. EJPA48, 31(2012) *note:g[Bracco]/2=g[Khodjamirian]

  25. Hosaka-san “Q” may isolate “qq” • λ and ρ motions split  known as isotope shift sqsq, SO Λc(1/2-,1/2- 3/2-,3/2-, 5/2-) r q-q q-q q Σc(1/2-,3/2-) q l ρ mode Σc(1/2-,1/2- 3/2-,3/2-,5/2-) q Q Q Λc(1/2-,3/2-) λ mode Σc(1/2+,3/2+) G.S. Λc(1/2+) 25

  26. discussed by A. Hosaka Excitation Energy Dependence f p D* • Production Rate in a quark-diquark model: • D* exchange at a forward angle • Radial integral of wave functions Taking Harmonic Oscillator Wave Functions • I~ (qeff/A)Lexp(-qeff2/2A2), where A: oscillator parameter (0.4~0.45 GeV) • For larger qeff, the relative rate of a higher L state to the GS increases as ~ (qeff/A)L • Spectroscopic Factor: g • pick up good/bad diquark configuration in a proton • A residual “ud” diquark acts as a spectator • Kinematic Factor w/ a propagator : • Spin Dependent Coefficient, C: • Products of CG coefficients based on quark-diquark spin configuration • Characterized by the spin operator in the vector meson exchange, D* g c u “ud” “ud” p Yc • =1/2 for Lc’s • =1/6 for Sc’s

  27. calculated by A. Hosaka Estimated Relative Yield • The estimation is valid for the D* exchange at a very forward angle. • The yields for some of Sc’s are suppressed due to g and C. • The C coefficient is characterized by spin dependent interaction at the D*NYc vertex. • Those for Lc’s are not suppressed very much at the excited states. • |I| reduces (increases!) an order of (qeff/A)L at higher L states.

  28. calculated by A. Hosaka Estimated Relative Yield (strange sector) Exp.: p(p-,K0)Y, D.J. Crennell et al., PRD6, 1220(1972) • The yield for S1/2+ is suppressed due to g and C. • The estimation is not very far from the experimental data but for S’s. • This already suggests a necessary modification of the model. • The measurement in charm sector provides valuable information on the reaction mechanism and structure of baryons.

  29. Production Rate

  30. Lc(1/2-) Lc(1/2+) charm qeff=1.37 GeV/c qeff=1.33 GeV/c r {fm} r {fm} L(1/2+) L(1/2-) strange qeff=0.27 GeV/c qeff=0.29 GeV/c r {fm} r {fm} L=0 L=1

  31. Summary… • Experimental Design • 1000 count/nb/100d • Background reduction • Signal Sensitivity: 0.1~0.2 nb for G~100 MeV state • 1 Decay particle detection inprove S/N very much • Improve the acceptance Decay particle Acceptance • Production Rate • A few nbfor Lc production seems a plausible estimation • Excitation Energy Dependence • The production rate is kept even at higher L states, depending on spin/isospin structures of baryons. • How are the rho-mode states excited? • How can we extract “diquark” in baryons • Can we can learn characteristic baryon structures from • Excitation Energy Spectrum • Population (Production Rate) • Decay (Partial) Width/Branching Ratio • Angular Correlation • What is similarity to/difference from strange baryons

  32. Structure and Decay Partial Width Illustrated by Hosaka Excited (qq) Good [qq] • L(1520) -> NK (D wave!)>πS, similarly L(1820), L(2100) • Possible explanation of narrow widths of Charmed Baryons

  33. Possible Subjects • CharmedBaryon Spectroscopy • N*, Y* resonances via (p,ρ), (p,K*) • h’, w, f, J/y, D, D* productions off N/A • “K-K-pp” strongly interacting hadronic system • S=-1, -2, -3 baryonspectroscopy w/ K beam • others We welcome you to join !

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