N* spectroscopy with meson photoproduction reactions

N* spectroscopy withmeson 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. 20-21, 2014

Collaborators ：T.-S. H. Lee （ Argonne Natl. Lab. ）S.X. Nakamura （ Osaka U. ）T. Sato （ Osaka U. ）

Baryons PDG (2012):http://pdg.lbl.gov

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 ofbaryons 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 ..

.Je.m.

N*, Δ*

πN, ηN, ππNKΛ, 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*

QCD

Lattice QCDQCD-inspiredHadron 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 modelsSoliton modelsHolographic QCD etc

Unitary multichannel reaction model

channel coupling effect

Dynamical coupled-channels model [Matsuyama, Sato, Lee, Phys. Rep. 439(2007)193]

＋ ＋ ＋＝ …V

π

N

π

N

η

N

K

Λ

π

N

e.g. ） πN scattering

Summing up all possible transitions between reaction channelsin the intermediate processes !!

ANL-Osaka dynamical coupled-channels analysisof meson production reactions

Exchangepotential Bare N* states

Transition potential

p, r, s, w,..

N N, D

s-channel u-channel t-channel contact

Exchange potentials

Bare N* statesN*bare

Bare N* states ：Corresponding to N* states definedin static hadron models excludingmeson-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 viacomprehensive analysis of meson production reactions

PDG 4*PDG 3*

Ours

Mass spectrum

Decay width

Construct the reaction modelby making a comprehensiveanalysis of

πN πN, ππN, ηN, KΛ, KΣ, ωN,…γ(*)N πN, ππN, ηN, KΛ, KΣ, ωN,…

Making analytic continuation of amplitudesto 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

pp pN

gp pN

pp hN

gp hp

pp KL, KS

gp K+L, KS

2006 – 2009(EBAC/JLab)

6 channels (gN,pN,hN,pD,rN,sN)

< 2 GeV

< 1.6 GeV

< 2 GeV

―

―

―

2010 – 2013(ANL-Osaka)

8 channels (gN,pN,hN,pD,rN,sN,KL,KS)

< 2.3 GeV

< 2.1 GeV

< 2.1 GeV

< 2.1 GeV

< 2.1 GeV

< 2.1 GeV

# of coupled channels

Fully combined analysis of pN , gN pN , hN , KL, KS reactions !!

HK, Nakamura, Lee, SatoPRC88 (2013) 035209

Julia-Diaz, Lee, Matsuyama, Sato, PRC76 (2007) 065201;

Julia-Diaz, et al., PRC77 (2008) 045205

Database for ANL-Osaka DCC analysis

22,348 data of unpolarized & polarized observables to fit !!

πN πN PWA from SAID πp ηN, KΛ, KΣ observables

γp πN, ηp, KΛ, KΣ observables

HK, Nakamura, Lee, SatoPRC88 (2013) 035209

unpolarized diff. crs. sec.

single pol.

beam-target

beam-recoil

target-recoil

Pseudoscalar meson photoproductions have 1 + 15 observables !!

“(Over-) complete” experimentshas been achieved by CLAS forKΛ and KΣ photoproductions !!!

γ p π0 p reaction

8ch DCC-analysis[HK, Nakamura, Lee, Sato, PRC88 (2013) 035209]

previous 6ch DCC-analysis (fitted to gN pN data only up to W = 1.6 GeV)[Julia-Diaz et al., PRC77 (2008) 045205]

1.6 GeV 1.9 GeV

Differential cross section (W = 1.08-2.1 GeV)

γ p π0 p reaction (2/3)

Σ

Note: In computing polarization obs. of pseudoscalar-meson photoproductions, we followedconvention defined in Sandorfi, Hoblit, Kamano, Lee, J. Phys. G38 (2011) 053001.

(See arXiv:1108.5411 for comparison of conventions used in different analysis groups.)

γ p π0 p reaction (3/3)

T

G

P

H

hat E8ch DCC-analysis[HK, Nakamura, Lee, Sato, PRC88 (2013) 035209]

Mass spectrum

Q2 : small Q2 : large

“bare” baryon

meson clouds

meson

baryon

？How effective d.o.f.’s describing baryon change with Q2 ?

N*, Δ*N

g* (q2 = -Q2)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 < Q2 < 10 (GeV/c)2.

JLab CLAS12 experiment (E12-09-003)

γ*

N

e

N*, Δ*

e’

Full

BareJulia-Diaz et al, PRC75 015205 (2007)

N D (1232) M1 transition form factor

Alexandrou et al., PRD83 (2011) 014501

Lattice QCD

Tiator et al., EPJST 198 (2011) 141

Transverse (transition) charge densities

proton proton

proton N*(1440)[Roper resonance]

bx [fm]bx [fm]

b y [f

m]

b y [f

m]

unpolarized density

unpolarized density

polarized in x-dir.

polarized in x-dir.

Δ(1232)at low Q2

light ：＋ chargedark ：０ or － charge

Transition form factors and baryon structure

Establish N*, Δ* spectrum in s1/2 = 1450 - 1750 MeV

The data we expect:

What we expect ELPH?

Δ(1600) 3/2+ : Roper-like state of Δ baryon　　　　　　 mass is still uncertain (1450-1700 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 1.6-1.7 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(101)

π, η, K, ππ,…γ

d

+ …

Computation of cross section O(106-107) times are needed in χ2 -fitting.

γ “n” π- pdσ/dΩ

Σ

TP

VERY PRELIMINARY !!

γ “n” π0 n

VERY PRELIMINARY !!

dσ/dΩ

Σ

γ “n” ηn

Σ

dσ/dΩ VERY PRELIMINARY !!

Predicted results for γ “n” K0Λ

Sensitive to F17 wave?

ALL observables @ W = 1.8 GeV

VERY PRELIMINARY !!

Double-pion production cross sections(current situation)

πNπΔ

πNπΔ, ρN

πNπΔ, ρN,σN

πNπΔ, σN

πNπΔ, ρN

8ch. model[HK, PRC88 (2013) 045208]

6ch. model[HK, Julia-Diaz, Lee, Matsuyama, Sato, PRC79 (2008) 025206]

Predicted πp ππN cross sections

8ch. model[HK, Nakamura, Lee, SatoPRC88 (2013) 035209]

6ch. model[HK, Julia-Diaz, Lee, Matsuyama, Sato, PRC80 (2009) 065203]

Predicted γp ππN cross sections

γNπΔ, ρN,σN

γNπΔ, ρN

γNπΔ, 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 s1/2 = 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 timetreatment 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.

DISregion

QEregion

RESregion

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:1303.6032]

Transition form factors are crucial not only for N* structure study, but alsofor neutrino-induced reactions !!

Collaboration@J-PARC 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

http://nuint.kek.jp

back up

γ p π+ n reaction (1/3)DCS Σ

8ch DCC-analysis[HK, Nakamura, Lee, Sato, PRC88 (2013) 035209]

γ p π+ n reaction (2/3)

P T

8ch DCC-analysis[HK, Nakamura, Lee, Sato, PRC88 (2013) 035209]

γ p π+ n reaction (3/3)

hat E G

H

8ch DCC-analysis[HK, Nakamura, Lee, Sato, PRC88 (2013) 035209]

γ p η p reaction (1/2)

DCS

8ch DCC-analysis[HK, Nakamura, Lee, Sato, PRC88 (2013) 035209]

γ p η p reaction (2/2)

TΣ

8ch DCC-analysis[HK, Nakamura, Lee, Sato, PRC88 (2013) 035209]

γ p K+ Λ reaction (1/2)DCS Σ

P

8ch DCC-analysis[HK, Nakamura, Lee, Sato, PRC88 (2013) 035209]

γ p K+ Λ reaction (2/2)T

Ox’

Oz’

Cx’

Cz’

8ch DCC-analysis[HK, Nakamura, Lee, Sato, PRC88 (2013) 035209]

γ p K+ Σ0 reactionDCS

Σ

P

Cx’

Cz’

8ch DCC-analysis[HK, Nakamura, Lee, Sato, PRC88 (2013) 035209]

γ p K0 Σ+ reactionDCS

P Σ

8ch DCC-analysis[HK, Nakamura, Lee, Sato, PRC88 (2013) 035209]

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