Quark masses, hyperfine interaction and exotic baryonsa Marek Karliner ([email protected]) Cavendish Laboratory, Cambridge University, United Kingdom and School of Physics and Astronomy,Tel Aviv University, Israel In collaboration with Harry J. Lipkin ahep-ph/0307243 and hep-ph/0307343 Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 1 Renaissance of QCD Spectroscopy Several new surprising experimental results: Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 2 Renaissance of QCD Spectroscopy Several new surprising experimental results: • two new extremely narrow mesons containing c and s¯ quarks (BaBar, CLEO, BELLE) Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 3 Renaissance of QCD Spectroscopy Several new surprising experimental results: • two new extremely narrow mesons containing c and s¯ quarks (BaBar, CLEO, BELLE) • new very narrow resonance precisely at D0∗D0 threshold (Belle, CDF) Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 4 Renaissance of QCD Spectroscopy Several new surprising experimental results: • two new extremely narrow mesons containing c and s¯ quarks (BaBar, CLEO, BELLE) • new very narrow resonance precisely at D0∗D0 threshold (Belle, CDF) • enhancements near pp¯ thresholds (BES, BELLE) Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 5 Renaissance of QCD Spectroscopy Several new surprising experimental results: • two new extremely narrow mesons containing c and s¯ quarks (BaBar, CLEO, BELLE) • new very narrow resonance precisely at D0∗D0 threshold (Belle, CDF) • enhancements near pp¯ thresholds (BES, BELLE) • exotic 5-quark KN resonances: Θ+, Ξ∗−− Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 6 Renaissance of QCD Spectroscopy Several new surprising experimental results: • two new extremely narrow mesons containing c and s¯ quarks (BaBar, CLEO, BELLE) • new very narrow resonance precisely at D0∗D0 threshold (Belle, CDF) • enhancements near pp¯ thresholds (BES, BELLE) • exotic 5-quark KN resonances: Θ+, Ξ∗−− Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 7 The discovery of Θ+ Narrow peak in K+ n invariant mass: Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 8 The discovery of Θ+ Narrow peak in K+ n invariant mass: =⇒ a pentaquark: su¯ udd, S = +1, exotic baryon resonance 35 30 25 20 Events 15 10 5 0 1.5 1.6 1.7 1.8 1.9 + 2 M(nK ) [ GeV/c ] mΘ+ = 1542 ± 5 MeV, ΓΘ+ ≤ 20 MeV LEPS, Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 9 The discovery of Θ+ Narrow peak in K+ n invariant mass: =⇒ a pentaquark: su¯ udd, S = +1, exotic baryon resonance 35 30 25 20 Events 15 10 5 0 1.5 1.6 1.7 1.8 1.9 + 2 M(nK ) [ GeV/c ] mΘ+ = 1542 ± 5 MeV, ΓΘ+ ≤ 20 MeV LEPS, DIANA, Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 9 The discovery of Θ+ Narrow peak in K+ n invariant mass: =⇒ a pentaquark: su¯ udd, S = +1, exotic baryon resonance 35 30 25 20 Events 15 10 5 0 1.5 1.6 1.7 1.8 1.9 + 2 M(nK ) [ GeV/c ] mΘ+ = 1542 ± 5 MeV, ΓΘ+ ≤ 20 MeV LEPS, DIANA, JLab (5.3 ± 0.5σ), Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 9 The discovery of Θ+ Narrow peak in K+ n invariant mass: =⇒ a pentaquark: su¯ udd, S = +1, exotic baryon resonance 35 30 25 20 Events 15 10 5 0 1.5 1.6 1.7 1.8 1.9 + 2 M(nK ) [ GeV/c ] mΘ+ = 1542 ± 5 MeV, ΓΘ+ ≤ 20 MeV LEPS, DIANA, JLab (5.3 ± 0.5σ), ELSA: I =0, Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 9 The discovery of Θ+ Narrow peak in K+ n invariant mass: =⇒ a pentaquark: su¯ udd, S = +1, exotic baryon resonance 35 30 25 20 Events 15 10 5 0 1.5 1.6 1.7 1.8 1.9 + 2 M(nK ) [ GeV/c ] mΘ+ = 1542 ± 5 MeV, ΓΘ+ ≤ 20 MeV LEPS, DIANA, JLab (5.3 ± 0.5σ), ELSA: I =0, HERMES, Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 9 The discovery of Θ+ Narrow peak in K+ n invariant mass: =⇒ a pentaquark: su¯ udd, S = +1, exotic baryon resonance 35 30 25 20 Events 15 10 5 0 1.5 1.6 1.7 1.8 1.9 + 2 M(nK ) [ GeV/c ] mΘ+ = 1542 ± 5 MeV, ΓΘ+ ≤ 20 MeV LEPS, DIANA, JLab (5.3 ± 0.5σ), ELSA: I =0, HERMES, ν(¯ν)N Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 9 The discovery of Θ+ Narrow peak in K+ n invariant mass: =⇒ a pentaquark: su¯ udd, S = +1, exotic baryon resonance 35 30 25 20 Events 15 10 5 0 1.5 1.6 1.7 1.8 1.9 + 2 M(nK ) [ GeV/c ] mΘ+ = 1542 ± 5 MeV, ΓΘ+ ≤ 20 MeV LEPS, DIANA, JLab (5.3 ± 0.5σ), ELSA: I =0, HERMES, ν(¯ν)N , WA21@CERN, LGT. consistency between experiments ? < re-analysis of old KN data: ΓΘ+ ∼ 1 MeV (Nussinov, Arndt et al.) Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 9 The discovery of Θ+ Narrow peak in K+ n invariant mass: =⇒ a pentaquark: su¯ udd, S = +1, exotic baryon resonance 35 30 25 20 Events 15 10 5 0 1.5 1.6 1.7 1.8 1.9 + 2 M(nK ) [ GeV/c ] mΘ+ = 1542 ± 5 MeV, ΓΘ+ ≤ 20 MeV LEPS, DIANA, JLab (5.3 ± 0.5σ), ELSA: I =0, HERMES, ν(¯ν)N , WA21@CERN, LGT. consistency between experiments ? < re-analysis of old KN data: ΓΘ+ ∼ 1 MeV (Nussinov, Arndt et al.) but analysis indirect: no exp. coverage of relevant energy Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 10 Most precise experiment so far: CLAS Collaboration at JLab γd → p nK+ K− Θ+ | {z } Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 11 Theoretical prejudices can be dangerous. 1984 Review of Particle Properties: Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 12 Theory A beautiful prediction from Skyrme model: Prasza lowicz(’87), Diakonov, Petrov & Polyakov(’97): mΘ+ ≈ 1530 MeV, P 1 + ΓΘ+ < 15 MeV, J = 2 , I =0 Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 13 Theory A beautiful prediction from Skyrme model: Prasza lowicz(’87), Diakonov, Petrov & Polyakov(’97): mΘ+ ≈ 1530 MeV, P 1 + ΓΘ+ < 15 MeV, J = , I =0 + 0 2 nK or pK + w Θ (1530) uudds¯ J J 10 of SU(3)f : J J J J J J J N(1710) w Jw J J J J J J J J J J J J J J J Σ(1890) J J w Jw Jw J J J J J J J J J J J J J J J J J J J J J J J J Ξ3/2(2070) J J J w Jw Jw Jw Ξ−π− or Σ−K− Ξ0π+ or Σ+K¯ 0 ddssu¯ uussd¯ important ... Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 14 Theory A beautiful prediction from Skyrme model: Prasza lowicz(’87), Diakonov, Petrov & Polyakov(’97): mΘ+ ≈ 1530 MeV, P 1 + ΓΘ+ < 15 MeV, J = , I =0 + 0 2 nK or pK + w Θ (1530) uudds¯ J J 10 of SU(3)f : J J J J J J J N(1710) w Jw J J J J J J J J J J J J J J J Σ(1890) J J w Jw Jw J J J J J J J J J J J J J J J J J J J J J J J J Ξ3/2(2070) J J J w Jw Jw Jw Ξ−π− or Σ−K− Ξ0π+ or Σ+K¯ 0 ddssu¯ uussd¯ important ... SU(3) breaking linear in Y = B − S Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 14 Theory A beautiful prediction from Skyrme model: Prasza lowicz(’87), Diakonov, Petrov & Polyakov(’97): mΘ+ ≈ 1530 MeV, P 1 + Γ + < 15 MeV, J = , I =0 nK+ pK0 Θ 2 or + w Θ (1530) uudds¯ J J 10 of SU(3)f : J J J J J J J N(1710) w Jw J J J J J J J J J J J J J J J Σ(1890) J J w Jw Jw J J J J J J J J J J J J J J J J J J J J J J J J Ξ3/2(2070) J J J w Jw Jw Jw Ξ−π− or Σ−K− Ξ0π+ or Σ+K¯ 0 ddssu¯ uussd¯ important ... SU(3) breaking linear in Y = B − S for S < 0, simple: ⇐⇒ counting s-quarks. 1 for S > 0: ∆h#s +#¯si = 3 Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 15 Theory Skyrme model sometimes does very well. N and ∆ spectrum from the Skyrme Model (Karliner & Mattis, 1984) Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 16 Theory But sometimes predicts too many exotics πN, KN, KN¯ Scattering, Skyrme Model vs. Experiment (Karliner & Mattis, 1986) Itzhaki, Klebanov, Ouyang & Rastelli: WZ normalization ? Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 17 Theory ⇒ Need to understand Θ+ in quark language • QCD: nothing prevents 5q states Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 18 Theory ⇒ Need to understand Θ+ in quark language • QCD: nothing prevents 5q states • but no direct QCD spectrum calculation yet (LC, lattice ?. ) Marek Karliner – Pentaquark Workshop, Jlab, Nov. 7, 2003 19 Theory ⇒ Need to understand Θ+ in quark language • QCD: nothing prevents 5q states • but no direct QCD spectrum calculation yet (LC, lattice ?. ) • Constituent Quark Model: ~σ · ~σ M = m − V (~λ · ~λ ) i j i i j m · m i i>j i j X X hyperfine interaction mi : effective quark mass, ~λ : SU|(3)c generators,{z ~σ: Pauli} spin operators Marek Karliner – Pentaquark Workshop, Jlab, Nov.