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Production of charmed baryons -- Rough estimate --

Atsushi Hosaka , RCNP (Osaka U). Production of charmed baryons -- Rough estimate --. • R ate for charm and strange productions Effective Lagrangian and Regge • Production of various baryons states Quark- diquark model. Charm and strange productions. Strategy.

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Production of charmed baryons -- Rough estimate --

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  1. Atsushi Hosaka, RCNP (Osaka U) Production of charmed baryons-- Rough estimate -- • Rate for charm and strange productions Effective Lagrangian and Regge • Production of various baryons states Quark-diquark model JPARC-Collab

  2. Charm and strange productions Strategy • We do not know much about charm production • Use an appropriate model for strange production from medium to high energy • Kinematically extend the model to the charm region Effective Lagrangian and/or Regge JPARC-Collab

  3. γp Vp μb Total 102 ρ About 100 times smaller than strangeness production 101 ω 1 φ ~ 100 10–1 J/ψ What about for the pion induced reaction 10–2 1 10 102 W [ GeV] JPARC-Collab

  4. Effective Lagrangian • Four possible processes; s, t, u and contact • At high energies and forward region, t-dominates s: suppressed, no resonance above 3 GeV u: suppressed kinematically c: unknown • D, D* exchanges allowed, but scalar is not D* π N N JPARC-Collab

  5. D-exchange D D* π N N JPARC-Collab

  6. Light flavor, u,d π+P ρ+p F1: 8mb F2: 7 mb k (cm) GeV

  7. Strangeness π+P K*+Λ(1116) F1: 8mb ------> 0.07 mb F2: 7 mb ------> 0.04 mb 1/120 1/170 k (cm) GeV

  8. Charm π+P D*+Λc(2226) F1: 8mb ------> 0.07 mb ------> 0.0006 mb F2: 7 mb ------> 0.04 mb ------> 0.00002mb = 20pb 1/120 1/120 1/170 1/2000 k (cm) GeV

  9. Regge's mechanism -- Brief idea -- ○ × Resonances K*, … can be exchanged t-channel No resonance exists with Q = 2 JPARC-Collab

  10. t-channel amplitude lt = 0, 1, 2, … For l = σ This violates unitarity Need to sum over all l Regge's method Regge trajectory Form factor ~ forward peak JPARC-Collab

  11. Regge trajectory t < 0 Scattering region 0 < t Physical particle region

  12. Features • Determines the asymptotic behavior s ∞ • Gives forward peak (diffractive pattern) • Agrees well with high energy scattering data ~ few hundred MeV above the strangeness threshold BUT difficult to determine • Absolute production rates • Form factors (t-dependence) Therefore, we may use • For relative production rate • At forward angle JPARC-Collab

  13. Vector vsPscalar trajectory  Vector >> Pscalar at large s JPARC-Collab

  14. Vector Reggeon, some model dependence

  15. • Naïve Regge • Kaidalov This is partly regarded as ambiguity in s0 • Grishina • Kaidalov JPARC-Collab

  16. Vector Reggeon, some model dependence σtot [μb] Naïve-Kaidalov Strange Grishina Kaidalov Naive Grishina Charm

  17. Production of Bcin a quark-diquark model JPARC-Collab

  18. Quark-diquark baryon Selem-Wilczek: e-Print: hep-ph/0602128 • ee has repulsive force, BUT • qq has attractive force SU(3)c :half of qqbar attraction SU(2)c : Same as qqbar Pauli-Gursey symmetry ~ several hundred MeV • Diquark can be seen better in heavy baryons GoodBad Color magnetic int.

  19. Pion induced charm production d λ-mode Q λ-mode baryons • D*-exchange couples to various B's lλ = 0, 1, 2 (18 baryons) • Estimate forward scattering strength ~ Regge shows • State dependence (ratio) is estimated by qd model JPARC-Collab

  20. Transitions to Qd baryons λ Bc(JP) N(1/2+) Forward JPARC-Collab

  21. Computation of matrix elements 1 JPARC-Collab

  22. Baryon wave functions Orbital χρ S=1/2 of good d (S = 0) + c χλ Spin S=1/2 of bad d (S = 1) + c χS S=3/2 of bad d (S = 1) + c Isospin Similar to spin WF Nucleon Charmed baryons JPARC-Collab

  23. Radial matrix elements IL JPARC-Collab

  24. Results kπ= 2.71 [GeV] Charm 1.00 0.02 0.16 0.90 1.70 0.02 0.03 0.04 0.19 0.18 0.50 0.88 0.02 0.02 0.01 0.03 0.07 0.07 JPARC-Collab

  25. Results kπ= 2.71 [GeV] Charm Strange kπ= 1.59 [GeV] 1.00 0.02 0.16 0.90 1.70 0.02 0.03 0.04 0.19 0.18 0.50 0.88 0.02 0.02 0.01 0.03 0.07 0.07 1.00 0.067 0.44 0.11 0.23 0.007 0.01 0.01 0.07 0.067 0.13 0.20 0.007 0.01 0.004 0.02 0.038 0.04 JPARC-Collab

  26. Summary • Regge approach: R(c)/R(s) = 1/100 – 1/1000 • Forward peak • Qd model shows spin-dependent rate • Some higher L states may have large production rate comparative to the ground state JPARC-Collab

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