LP 07 August 13 18 2007 Daegu Korea

LP 07, August 13 -18, 2007, Daegu, Korea Heavy flavor baryons Roman Mizuk (ITEP, Moscow) Belle Collaboration charm and beauty baryons pentaquark searches

Reminder on Heavy Quark Baryons made from u, d, s, c quarks similar multiplets if c quark is exchanged by b quark antisymmetric 3 F One heavy quark – symmetric 6 F Total space-flavor-spin wave function must be symmetric example S-wave 3 F 6 F slight=0 slight=1 JP=1/2+ or 3/2+ 8 S-wave isospin multiplets, 35 P-wave, 85 D-wave, . . Heavy Quark Symmetry jlight decouples exact for m. Q → excitation spectra are independent of heavy quark flavor Simplification: Heavy quark - light diquark picture. Laboratory to test QCD.

Experimental Status 2 years ago Charmed baryons Beauty baryons

Experimental Status Many new states observed recently at B-factories TEVATRON Important ingredients PID, high momentum detached vertex Charmed baryons Beauty baryons

Λc c[ud]

Observation of Λc(2940)+ by Ba. Bar D 0 p PRL 98, 012001 Measurements of M and Γ are consistent Λc(2880) CLEO Λcπ+π- Λc(2940) NEW New decay wrong-sign mechanism: combinations D sidebands heavy quark → meson. 0 Σc(2455)π→Λc+π+πPRL 98, 262001 Λc(2880) Belle confirmed Λc(2765) Λc(2940) Ba. Bar: no isospin partners in D+p 2880, 2940 are isoscalars Exotics? Λc(2940)+ mass is 5 Me. V below D*p threshold molecule? He, Liu, Zeng, hep-ph/0606015 Conventional baryon? JP=5/2 -, 1/2+, 3/2+, . . Chen, Chua, PRD 75, 094017 (2007) ( mass, Garcilazo, Vijande, Valcarce, JPG 34, 961 (2007) Chen, Liu, Deng, Zhu, PRD 75, 094017 (2007) decay pattern) More experimental studies to discriminate. Γ(Σc*π): Γ(Σcπ): Γ(D 0 p), …

Λc(2880)+ spin-parity from Belle PRL 98, 262001 Angular analysis of Λc(2880)→Σc(2455)π Resonant structure of Λc(2880)→Λc+π+πm(Λcπ) helicity angle Σc(2455) Σc(2520) evidence J=5/2 is favored over 3/2 (4. 5σ) or 1/2 (5. 4σ) Capstick, Isgur PRD 34, 2809 (1986) Quark Model: 5/2 - 2900 3130 7/2 - 3125 5/2+ 2910 3140 7/2+ 3175 Chen, Chua, PRD 75, 094017 (2007) Heavy Quark Symmetry: 5/2 - R=1. 4 5/2+ is favored over 5/25/2+ R~0. 3 predicted in string theory Selem, Wilczek, hep-ph/0602128 @ leading Regge trajectory with Λc+ 1/2+ and Λc(2625)+ 3/2 - Λc(2880)+ is likely 5/2+

Σc cdd, c{ud}, cuu

Observation of Σc(2800) isotriplet by Belle Λc+π- Λc + π0 feed-down Σc(2800)0 NEW Λc + π+ Σc(2800)+ NEW feed-down PRL 94, 122002 Σc(2800)++ NEW Feed-down from Λc(2880)+→Σcπ→Λc+π+π- Measurements of M, Γ and σ are consistent Mass, width Σc(2800) can be 3/2 - (? ) More experimental studies to confirm JP. Capstick, Isgur, PRD 34, 2809 (1986) Pirjol, PRD 56, 5487 (1997) Mass of Σc(2800) is at D 0 p threshold.

Ξc csd, csu

Observation of Ξc(2980) and Ξc(3080) by Belle PRL 97, 162001 Λc + K- π+ Ξc(3080)+ NEW hep-ex/0607042 Ξc(3080)+ Ba. Bar confirmed Ξc(2980)+ NEW Λc + K- π+ Ξc(2980)+ New decay mechanism: s-quark → meson. Λc + Ks π- Ξc(3080)0 NEW Measurements of M and Γ are consistent resonant structure Ba. Bar confirmed also Ξc(3080)0 Mass D-wave excitations ? Ξc(2980) 1/2+, 3/2+, . . Ξc(3080) 5/2+, . . Rosner JPG 34, S 127 (2007) Chen, Chua, PRD 75, 094017 (2007) Garcilazo, Vijande, Valcarce, JPG 34, 961 (2007) Chen, Liu, Deng, Zhu, PRD 75, 094017 (2007) Ebert, Faustov, Galkin, ar. Xiv: 0705. 2957 More experimental studies to assign JP.

Evidence for Ξc(3055) and Ξc(3123) from Ba. Bar Presented at EPS-HEP 2007 Σc(2455)++K-→Λc+K-π+ Ξc(2980)+ Ξc(3055)+ NEW Ξc(3080)+ Σc(2520)++K-→Λc+K-π+ Ξc(3080)+ Ξc(3123)+ evidence hep-ex/. . . (preliminary) More experimental studies to assign JP.

Study of B+→Λc+Λc-K+ by Ba. Bar B+→Λc+Λc-K+ decay has been observed by Belle PRL 97, 202003 (2006) NEW Ba. Bar: confirmation, resonant structure. Λc + Λc - K- Λc + K- NEW B- meson confirmed phase-space sidebands mbc (Ge. V/c 2) Excited Ξc? not seen in continuum Ba. Bar “More data are needed before firm conclusions can be drawn. ”

Ωc css

PRL 97, 232001 Observation of Ωc* by Ba. Bar Ωc* significance 5. 2σ NEW Ωc 0 g Result m(Ωc*) – m(Ωc) = (70. 8 ± 1. 0 ± 1. 1) Me. V/c 2 Last unobserved ground state charmed baryon. Comparison with predictions m(Ωc*) – m(Ωc) data Ebert et al, PRD 72, 034026 (2005) QM with heavy-quark-light-diquark Burakovsky et al, PRD 56, 7124 (1997) Regge framework Lichtenberg et al, PRD 53, 6678 (1996) Mass sum rules Rosner, PRD 52, 6461 (1995) Spin-flavor wave-functions Martin et al, PLB 355, 345 (1995) potential model Mathur et al, PRD 66, 014502 (2002) Lattice NRQCD (quenched) Jenkins, PRD 54, 4515 (1996) 1/MQ and 1/Nc expansion Savage, PLB 359, 189 (1995) Chiral Perturbation Theory Roncaglia et al, PRD 52, 1722 (1995) Feynman-Hellman theorem Good agreement

Σb bdd, b{ud}, buu

ar. Xiv: 0706. 3868 Observation of Σb and Σb* by CDF Λb 0π- Λb 0π+ Blind signal region Λb 0→Λc+π-

ar. Xiv: 0706. 3868 Observation of Σb and Σb* by CDF Λb 0π- blind BG fixed blind Λb 0π+ Λb 0→Λc+π-

ar. Xiv: 0706. 3868 Observation of Σb and Σb* by CDF Λb blind 0π- Λb 0→Λc+πΣbΣb*NEW Korner et al, PPNP 33, 787 Λb 0π- Fix all widths: Fix shape and normalization of bg. Results (Me. V/c 2): BG fixed blind Λb 0π+ Σb+ NEW Σb*+ NEW Λb 0π+ Significance >5. 2σ (4 peaks vs. BG only) Each peak >3 σ (except Σb+)

ar. Xiv: 0706. 3868 Observation of Σb and Σb* by CDF Λb blind 0π- Λb 0→Λc+πΣbΣb*NEW Korner et al, PPNP 33, 787 Λb 0π- Fix all widths: Fix shape and normalization of bg. Results (Me. V/c 2): BG fixed blind Λb 0π+ Σb*+ NEW Λb 0π+ Significance >5. 2σ (4 peaks vs. BG only) Each peak >3 σ (except Σb+) Comparison with predictions expect m(Σb–) – m(Σb+) = 5 -7 Me. V Ebert et al, PRD 72, 034026 (2005) QM with heavy-quark-light-diquark Capstick, Isgur, PRD 34, 2809 (1986) relativised QM m(Σb)–m(Λb) data m(Σb*)–m(Σb) Karliner, Lipkin, PLB 575, 249 (2003) QM Mathur et al, PRD 66, 014502 (2002) Lattice NRQCD (quenched) Jenkins, PRD 54, 4515 (1996) 1/MQ and 1/Nc expansion Roncaglia et al, PRD 52, 1722 (1995) Feynman-Hellman theorem Good agreement

Ξb bsd, bsu

Observation of Ξb- by D 0 and CDF Ξb -→ J/ψ Ξ- ar. Xiv: 0706. 1690 Ξ b. NEW Mass measurements are consistent Proper decay time distribution consistent with expected Ξb lifetime PRL 99, 052001 J/ψ Ξ- ar. Xiv: 0707. 0589 PRL 99, 052002 Ξ b. NEW Comparison with predictions Lattice QCD QM HQET Good agreement

Summary on Heavy Quark Baryons Charmed baryons Ξc(3080) Ξc(3055) Ξc(2980) Λc(2940) Beauty baryons CLEO Belle Ba. Bar D 0 CDF Λc(2880) Σc(2800) Ωc* Σb* Ξb Σb Ground state SU(3) multiplets of charmed New era in beauty baryons are complete. Flood of highly excited charmed baryons. spectroscopy.

Reminder on Pentaquarks Θ(1540)+ |uudds> Θ(1540)+ predicted in Chiral Soliton Model Observed in γn→Θ+K- → (K+n)K- and K+n→Θ+→p. KS M ~ 1540 Me. V/c 2 Γ < 1 Me. V Low Γ and M are difficult to explain Initial evidence: Group LEPS DIANA CLAS-d SAPHIR ITEP- CLAS-p HERMES ZEUS SVD-2 TOF Reaction g. C K+K- X K+Xe K 0 p Xe’ gd K+K-p(n) gp K+K 0(n) A K 0 p X gp p+ K-K+(n) e+d K 0 p X e+p e’K 0 p X p. A K 0 p. X pp K 0 p. S+ σ’s 4. 6 4. 4 5. 2 4. 8 6. 7 7. 8 ~5 ~5 5. 5 4 -6 Also many null results, not easily comparable. Repeat measurements with high statistics + LEPS – CLAS – Belle + SVD-2

Introduction to Pentaquarks Θ(1540)+ |uudds> Θ(1540)+ predicted in Chiral Soliton Model Observed in γn→Θ+K- → (K+n)K- and K+n→Θ+→p. KS M ~ 1540 Me. V/c 2 Γ < 1 Me. V Low Γ and M are difficult to explain Initial evidence: Group LEPS DIANA CLAS-d SAPHIR ITEP- CLAS-p HERMES ZEUS SVD-2 TOF Reaction g. C K+K- X K+Xe K 0 p Xe’ gd K+K-p(n) gp K+K 0(n) A K 0 p X gp p+ K-K+(n) e+d K 0 p X e+p e’K 0 p X p. A K 0 p. X pp K 0 p. S+ σ’s 4. 6 4. 4 5. 2 4. 8 6. 7 7. 8 ~5 ~5 5. 5 4 -6 Also many null results, not easily comparable. Repeat measurements with high statistics + LEPS – CLAS – Belle + SVD-2 NEW? PDG 2006

New DIANA result PAN 70, 35 (2007) K+ Xe → p KS Xe’ M(p. KS) Statistics x 1. 6 Θ(1540)+ signal confirmed, significance increased from 4. 4 to 5. 3σ NEW estimation of Θ(1540)+ width 445<p. K+<525 Me. V Assumption DIANA finds no Θ+ signal for p. K+>525 Me. V M(p. KS) p. K+>525 Me. V Γ, Me. V DIANA Belle Nuclear suppression is the same for Θ+ and nonresonant K 0 p 0. 9 ± 0. 3 <0. 64 No nuclear suppression for Θ+ 0. 36 ± 0. 11 <0. 28 ? my estimate Contradiction with Belle persists (2. 2σ, 2. 4%) Inelastic Θ(1540)+ production will decrease Belle upper limit 17 events expected MC verified on tagged kaon data at Belle -3 found 2. 9σ fluctuation, decreases significance of DIANA signal Evidence for Θ(1540)+ from DIANA is weak.

EPJC 49, 499 (2007) N → Θ+ X New NOMAD result Θ+ Θ(1540)+ signal is not confirmed NOMAD Preliminary based on subsaple Upper Limit on Θ+ production rate per interaction vs. x. F NOMAD result can be compared with ITEP- result Θ+ production rate ~10 -3 Θ+ For large part of x. F range NOMAD and ITEP- results are in conflict.

PLB 649, 252 (2007) pp → p. K 0Σ+ New COSY-TOF results Statistics x 10, improved detection capability Θ(1540)+ signal not confirmed NEW Previous Comparison Θ+ Background shape from new data. In previous analysis background was underestimated significance lower than claimed. Evidence for Θ(1540)+ from COSY-TOF is negated.

New H 1 result PLB 639, 202 (2006) ep → p. KSX No Θ+ signal H 1 result can be compared with ZEUS result M(p. KS) ZEUS (preliminary) Q 2>20 Ge. V 2, 0. 04<y<0. 95 H 1 Extrapolated to ZEUS y-region. H 1 and ZEUS results are in conflict.

hep-ex/0509033 SVD-2 result: the most significant Θ+ signal Statistics x 8 Θ(1540)+ signal confirmed, significance increased from 5. 5 to ~8σ p. A → KSp. X M(p. KS) M = 1522 Me. V s = 12 Me. V Nevnt = 205 M(p. KS) KS decays inside / outside Vertex Detector M = 1523 Me. V s = 12 Me. V Nevnt = 165 Θ(1540)+ is produced with small x. F Group SVD-2 σ[Θ(1540)+] / σ[Λ(1520)] s, Ge. V 8 -12% 12 HERA-B <2% at 95% C. L. 40 CDF <3% at 90% C. L. 2000 For central production difference in energy should not be important. SVD-2 result strongly contradicts HERA-B, CDF.

Other new results on pentaquarks KEK-PS E 522 PLB 635, 72(2006) “Search for Θ+ via π-p→K-X reaction near threshold” 2. 5σ signal at M=1530 Me. V OBELIX (LEAR, CERN) “Search for the Θ+ pentaquark in antiproton 4 He annihilation at rest”. NPA 779, 116(2006) CLAS PRL 97, 032001(2006) “Search for the Θ+ pentaquark in the γd→Λn. K+ reaction measured at CLAS” CLAS PRD 74, 032001(2006) “Search for the Θ+ pentaquark in the reactions γp→K 0 K+n and γp→K 0 K 0 p ” FOCUS PLB 639, 604(2006) “Search for a pentaquark decaying to p. KS” DELPHI ar. Xiv: 0708. 0415 Search for Pentaquarks in the Hadronic Decays of the Z Boson with the DELPHI Detector” No significant Θ+ signals. No new positive results for doubly strange pentaquark Φ(1860) or charmed pentaquark Θc(3100)0. “No stars” in PDG 2006 not discussed here.

Summary on Θ(1540)+ Group Reaction σ’s LEPS g. C K+K- X 4. 6 LEPS gd p. K- X DIANA K+Xe K 0 p Xe’ 4. 4 CLAS-d gd K+K-p(n) 5. 2 SAPHIR gp K+K 0(n) 4. 8 ITEP- A K 0 p X 6. 7 In conflict with NOMAD. CLAS-p gp p+ K-K+(n) 7. 8 Not accessible in new data (energy too low). HERMES e+d ~5 Contradicts Ba. Bar e. Be→p. KSX (statistics x 100 larger). ZEUS e+p e’K 0 p X ~5 In conflict with H 1. SVD-2 p. A K 0 p. X 5. 5 TOF pp K 0 p. S+ 4 -6 K 0 p ~5σ unpublished ~5σ X 5. 4σ New data are taken (2007). Statistics x 3. Contradiction with Belle persists. unpublished ~8σ Contradicts HERA-B, CDF. Not a single convincing evidence for Θ(1540)+ For experiment with positive result experiment with similar conditions but null result. Evidence for Θ(1540)+ pentaquark is weak

Conclusions Impressive progress in heavy flavor baryons # charmed baryons 12 → 18 # beauty baryons 1 → 4 over last 2 years Λc(2880)+, Ωc*, Σb*, Ξb provide important constraints for theory. To use other new states: Λc(2940), Σc(2800), Ξc(2980), Ξc(3055), Ξc(3080), we need symbiosis between theory and experiment. Experiments are consistent and experimental results are robust. Experimental evidence for pentaquarks is weak More null results since PDG 2006: COSY-TOF, H 1, NOMAD, . . . Very low Θ+ width: DIANA Γ = (0. 36 ± 0. 11) Me. V New results are expected from LEPS, HERA-II. New challenges for theory?

Back-up

Doubly charmed baryons hep-ex/0702001 SELEX Λc + K- π+ Ξcc Ξc + π+ πΞcc+ + Not confirmed by Ba. Bar and Belle. cc+ c+ K- + cc+ cc 0 + Selex’s cc(3520)+ is found neither in c+ K- + nor in c 0 + also not seen in photo production (FOCUS) New decay channel.