N* spectroscopy with meson photoproduction reactions Hiroyuki Kamano (RCNP, Osaka U.) 東北大ELPH研究会「GeV領域光子で探るメソン生成反応の物理」 Feb , 2014 Collaborators ： T.-S. H. Lee （ Argonne Natl. Lab. ） S.X. Nakamura （ Osaka U. ） T. Sato （ Osaka U. ）

Baryons PDG (2012): qqq (I=1/2) [q = u or d] qqq (I=3/2) [q = u or d] qqs (I=0) [q = u or d] qqs (I=1) [q = u or d] qss (I=1/2) [q = u or d] sss (I=0) qqc (I=0) [q = u or d] qqc (I=1) [q = u or d] qsc (I=1/2) [q = u or d] ssc (I=0) qcc (I=1/2) [q = u or d] qqb (I=0) [q = u or d] ssb (I=0) qsb (I=1/2) [q = u or d] qqb (I=1) [q = u or d] Isospin Baryon Spectroscopy: Understanding nature of baryons and their excitations Mass, width, spin, parity …? Internal structure? How produced in reaction processes? How interact with other particles?

Meson photoproduction reactions in N*, Δ* resonance region γp reaction total cross section in N* 、 Δ* region （ Database is provided by Kanda-san ） “Δ-region” Region our model covers γ N... J e.m. N*, Δ* πN, ηN, ππN KΛ, KΣ, ωN, …  Study electromagnetic interactions of N* 、 Δ*  Used also for establishing N*, Δ* mass spectrum and searching for new N*, Δ* resonances

Approaches to N* spectroscopy JLab, ELSA, MAMI, SPring-8, ELPH,… Mass, width, form factors, etc of N* & Δ* QCDQCDQCDQCD Lattice QCD QCD-inspired Hadron Models Analysis based on reaction theory Reaction Data Multichannel unitary condition: ANL-Osaka/EBAC-JLab, Bonn-Gatchina, Carnegie Mellon-Berkely, Dubna-Mainz-Taipei, VPI/GWUGeorge, Giessen, Juelich, Karlsruhe-Helsinki, … N* spectroscopy with multichannel unitary reaction models has made a significant progress.  Ensures conservation of probability.  Defines analytic structure (branch points, cuts) of the amplitudes in complex-E plane. Our approach !! Constituent quark models Soliton models Holographic QCD etc Constituent quark models Soliton models Holographic QCD etc

Unitary multichannel reaction model channel coupling effect Dynamical coupled-channels model [Matsuyama, Sato, Lee, Phys. Rep. 439(2007)193] ＋ ＋ ＋＝ … V πNπN πNπN ηNηN KΛKΛ πNπN e.g. ） πN scattering Summing up all possible transitions between reaction channels in the intermediate processes !!

ANL-Osaka dynamical coupled-channels analysis of meson production reactions Exchange potential Exchange potential Bare N* states Transition potential  N N,  s-channel u-channel t-channelcontact Exchange potentials Bare N* states N* bare Bare N* states ： Corresponding to N* states defined in static hadron models excluding meson-baryon continuums ＋ ＋ ＋ ＝ ＝ ＋＋＋ bare N* Formation of hadron resonances core(bare) meson cloud meson baryon Physical N*s will be a “mixture” of the two pictures:

Extraction of baryon resonances via comprehensive analysis of meson production reactions PDG 4* PDG 3* Ours Mass spectrum Decay width Construct the reaction model by making a comprehensive analysis of πN  πN, ππN, ηN, KΛ, KΣ, ωN,… γ (*) N  πN, ππN, ηN, KΛ, KΣ, ωN,… Making analytic continuation of amplitudes to complex E-plane (Suzuki, Sato, Lee PRC79(2009)025205; PRC82(2010)045206)  mass 、 width  pole posiiton  coupling constants  “(residues) 1/2 ” at the pole poles of amplitude = baryon resonance!! π + p  K + Σ + DCS P

Our analyses of meson production reactions  p   N  p   N  p   N  p   p  p  K ,   p  K +  K  2006 – 2009 (EBAC/JLab) 6 channels (  N,  N,  N, ,  N,  N) < 2 GeV < 1.6 GeV < 2 GeV ― 2010 – 2013 (ANL-Osaka) 8 channels (  N,  N,  N, ,  N,  N,K ,K  ) < 2.3 GeV < 2.1 GeV # of coupled channels Fully combined analysis of  N,  N   N,  N, K , K  reactions !! HK, Nakamura, Lee, Sato PRC88 (2013) Julia-Diaz, Lee, Matsuyama, Sato, PRC76 (2007) ; Julia-Diaz, et al., PRC77 (2008)

Database for ANL-Osaka DCC analysis 22,348 data of unpolarized & polarized observables to fit !! πN  πN PWA from SAIDπp  ηN, KΛ, KΣ observables γp  πN, ηp, KΛ, KΣ observables HK, Nakamura, Lee, Sato PRC88 (2013) unpolarized diff. crs. sec. single pol. beam-target beam-recoil target-recoil Pseudoscalar meson photoproductions have observables !! “(Over-) complete” experiments has been achieved by CLAS for KΛ and KΣ photoproductions !!!

γ p  π 0 p reaction 8ch DCC-analysis [HK, Nakamura, Lee, Sato, PRC88 (2013) ] previous 6ch DCC-analysis (fitted to  N   N data only up to W = 1.6 GeV) [Julia-Diaz et al., PRC77 (2008) ] 1.6 GeV1.9 GeV Differential cross section (W = GeV)

γ p  π 0 p reaction (2/3) Σ Note: In computing polarization obs. of pseudoscalar-meson photoproductions, we followed convention defined in Sandorfi, Hoblit, Kamano, Lee, J. Phys. G38 (2011) (See arXiv: for comparison of conventions used in different analysis groups.)

γ p  π 0 p reaction (3/3) T G P H hat E 8ch DCC-analysis [HK, Nakamura, Lee, Sato, PRC88 (2013) ]

Mass spectrum

Q 2 : small Q 2 : large “bare” baryon meson clouds meson baryon？ How effective d.o.f.’s describing baryon change with Q 2 ? N*, Δ* N  (q 2 = -Q 2 ) q N-N* electromagnetic transition form facctor “hadronic” picture “partonic” picture Transition form factors and baryon structure Measurement of p(e,e’π)N & p(e,e’ππ)N for 5 < Q 2 < 10 (GeV/c) 2.  JLab CLAS12 experiment (E ) γ* N e N*, Δ* e’

Full Bare Julia-Diaz et al, PRC (2007) N   (1232) M1 transition form factor Alexandrou et al., PRD83 (2011) Lattice QCD Tiator et al., EPJST 198 (2011) 141 Transverse (transition) charge densities proton  proton proton  N*(1440)[Roper resonance] b x [fm] b y [fm] unpolarized density polarized in x-dir. Δ(1232) at low Q 2 light ：＋ charge dark ：０ or － charge Transition form factors and baryon structure

Establish N*, Δ* spectrum in s 1/2 = MeV The data we expect: What we expect ELPH? Δ(1600) 3/2 + : Roper-like state of Δ baryon mass is still uncertain ( MeV) N(1685) ? ? : Seen in γd  (ηn) p  New N*, Δ* could exist behind large N* (1535) 1/2 - 、 N*(1650) 1/2 - 、 N*(1520) 3/2 - resonances !! (Many channels open in GeV region) Double meson productions & Deuteron(neutron) target reactions ππN (~ 1220 MeV) 、 πηN(~ 1620 MeV) 、 ηN (~ 1490 MeV) 、 KΛ (~ 1610 MeV) 、 KΣ (~ 1680 MeV) 、 ωN (~ 1720 MeV)

Our tasks Reducing computing time Extension to deuteron-target reactions （ Computing time for double meson productions ） （ Computing time for single meson productions ） = O(10 1 ) π, η, K, ππ,… γ d + … Computation of cross section O( ) times are needed in χ 2 -fitting.

γ “n”  π - p dσ/dΩ Σ T P VERY PRELIMINARY !!

γ “n”  π 0 n VERY PRELIMINARY !! dσ/dΩ Σ

γ “n”  ηn Σ dσ/dΩ VERY PRELIMINARY !!

Predicted results for γ “n”  K 0 Λ Sensitive to F17 wave? ALL W = 1.8 GeV VERY PRELIMINARY !!

Double-pion production cross sections (current situation) πN  πΔ πN  πΔ, ρN πN  πΔ, ρN,σN πN  πΔ, σN πN  πΔ, ρN 8ch. model [HK, PRC88 (2013) ] 6ch. model [HK, Julia-Diaz, Lee, Matsuyama, Sato, PRC79 (2008) ] Predicted πp  ππN cross sections

8ch. model [HK, Nakamura, Lee, Sato PRC88 (2013) ] 6ch. model [HK, Julia-Diaz, Lee, Matsuyama, Sato, PRC80 (2009) ] Predicted γp  ππN cross sections γN  πΔ, ρN,σN γN  πΔ, ρN γN  πΔ, σN Double-pion production cross sections (current situation)

Establish high-mass N*, Δ* mass spectrum The data we expect & our tasks What we expect LEPS/LEPS2 ?  Poorly established  Very large width  Approaches based on reaction theory will become more important.  In the future, we aim at establishing N*, Δ* spectrum up to s 1/2 = 2.5 GeV that can access with LEPS/LEPS2. Differential cross section and polarizations of γN  η’N, ΦN, K*Y, KΣ*,… Our tasks ： Reducing computation time treatment of 4-body channel （ πππN ）（ ρΔ channel ）

meson productions with electron beam ?? Other topics e+d reactions are necessary for extracting Q2 dependence of neutron target n-N* transition form factors. DIS region QE region RES region CP phase & mass hierarchy studies with atmospheric exp. T2K Construction of unified neutrino reaction model describing overlapping regions between QE, RES, and DIS regions !! Y. Hayato (ICRR, U. of Tokyo), M. Hirai (Tokyo U. of Sci.) H. Kamano (RCNP, Osaka U.), S. Kumano (KEK) S. Nakamura (YITP, Kyoto U.), K. Saito (Tokyo U. of Sci.) M. Sakuda (Okayama U.), T. Sato (Osaka U.) [  arXiv: ] Transition form factors are crucial not only for N* structure study, but also for neutrino-induced reactions !! Branch of KEK Theory Center & 新学術領域研究「ニュートリノフロンティアの融合と進化」 C02 班

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γ p  π + n reaction (1/3) DCSΣ 8ch DCC-analysis [HK, Nakamura, Lee, Sato, PRC88 (2013) ]

γ p  π + n reaction (2/3) PT 8ch DCC-analysis [HK, Nakamura, Lee, Sato, PRC88 (2013) ]

γ p  π + n reaction (3/3) hat EG H 8ch DCC-analysis [HK, Nakamura, Lee, Sato, PRC88 (2013) ]

γ p  η p reaction (1/2) DCS 8ch DCC-analysis [HK, Nakamura, Lee, Sato, PRC88 (2013) ]

γ p  η p reaction (2/2) T Σ 8ch DCC-analysis [HK, Nakamura, Lee, Sato, PRC88 (2013) ]

γ p  K + Λ reaction (1/2) DCS Σ P 8ch DCC-analysis [HK, Nakamura, Lee, Sato, PRC88 (2013) ]

γ p  K + Λ reaction (2/2) T Ox’ Oz’ Cx’ Cz’ 8ch DCC-analysis [HK, Nakamura, Lee, Sato, PRC88 (2013) ]

γ p  K + Σ 0 reaction DCS Σ P Cx’ Cz’ 8ch DCC-analysis [HK, Nakamura, Lee, Sato, PRC88 (2013) ]

γ p  K 0 Σ + reaction DCS PΣ 8ch DCC-analysis [HK, Nakamura, Lee, Sato, PRC88 (2013) ]

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