バリオン励起状態の研究における中間子生成反応デー

N* spectroscopy with
meson photoproduction reactions
Hiroyuki Kamano
(RCNP, Osaka U.)
Collaborators：
T.-S. H. Lee（Argonne Natl. Lab.）
S.X. Nakamura（Osaka U.）
T. Sato（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
qqc (I=0)
[q = u or d]
Isospin
Baryon Spectroscopy:
Understanding nature of
baryons and their excitations
qqc (I=1)
[q = u or d]
qqq (I=1/2)
[q = u or d]
qsc (I=1/2)
[q = u or d]
ssc (I=0)
qss (I=1/2)
Mass, width, spin, parity …?
qcc (I=1/2)
[q = u or d]
[q = u or d]
Internal structure?
qqb (I=0)
sss (I=0)
How produced in reaction processes?
qqq (I=3/2)
[q = u or d]
qqs (I=1)
qqb (I=1)
How interact with other
particles?
[q = u or d]
[q = u or d]
qsb (I=1/2)
[q = u or d]
ssb (I=0)
Baryons
qqs (I=0)
[q = u or d]
[q = u or d]
PDG (2012):
http://pdg.lbl.gov
Meson photoproduction reactions in
N*, Δ* resonance region
πN, ηN, ππN
KΛ, KΣ, ωN, …
Region our model covers
“Δ-region”
γ
.
N
Je.m.
N*, Δ*
.
.
 Study electromagnetic
interactions of N*、Δ*
 Used also for establishing N*, Δ*
mass spectrum and searching for
new N*, Δ* resonances
γp reaction total cross section in N*、Δ* region
（Database is provided by Kanda-san）
Approaches to N* spectroscopy
Reaction Data
JLab, ELSA, MAMI,
SPring-8, ELPH,…
Analysis based on reaction theory
 Multichannel unitary condition:
Mass, width,
form factors, etc of
N* & Δ*
QCD-inspired
Hadron Models
Lattice QCD
QCD
Constituent quark models
Soliton models
Holographic QCD etc
N* spectroscopy with multichannel
unitary reaction models has made
a significant progress.
Our approach !!

Ensures conservation of probability.

Defines analytic structure (branch points,
cuts) of the amplitudes in complex-E plane.
ANL-Osaka/EBAC-JLab, Bonn-Gatchina,
Carnegie Mellon-Berkely, Dubna-Mainz-Taipei,
VPI/GWUGeorge, Giessen, Juelich,
Karlsruhe-Helsinki, …
Unitary multichannel reaction model
Dynamical coupled-channels model [Matsuyama, Sato, Lee, Phys. Rep. 439(2007)193]
channel coupling effect
e.g.）πN scattering
π
N
π
N
η
＝
V
＋
＋
N
K
π
Λ
N
＋
…
Summing up all possible transitions between reaction channels
in the intermediate processes !!
ANL-Osaka dynamical coupled-channels analysis
of meson production reactions
Transition potential
Physical N*s will be a “mixture” of the two pictures:
baryon
meson cloud
Exchange
potential
Bare N* states
core
(bare)
meson
Formation of hadron
resonances u-channel
s-channel
＝
N
bare N*
＋
N, D
t-channel
＋
contact
p, r, s, w,..
＋
Exchange potentials
＝
N*bare
＋
Bare N* states
Bare N* states：
Corresponding to N* states defined
in static hadron models excluding
meson-baryon continuums
＋
＋
Extraction of baryon resonances via
comprehensive analysis of meson production reactions
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,…
Mass spectrum
Making analytic
continuation of amplitudes
to complex E-plane
(Suzuki, Sato, Lee
PRC79(2009)025205;
PRC82(2010)045206)
Ours
PDG 4*
PDG 3*
DCS
π+ p  K+ Σ+
poles of amplitude =
baryon resonance!!
P
 mass、width  pole posiiton
 coupling constants
 “(residues)1/2” at the pole
Decay width
Our analyses of meson production reactions
Fully combined analysis of pN , gN  pN , hN , KL, KS reactions !!
2006 – 2009
2010 – 2013
(EBAC/JLab)
(ANL-Osaka)
6 channels
8 channels
(gN,pN,hN,pD,rN,sN)
(gN,pN,hN,pD,rN,sN,KL,KS)
 pp  pN
< 2 GeV
< 2.3 GeV
 gp  pN
< 1.6 GeV
< 2.1 GeV
 pp  hN
< 2 GeV
< 2.1 GeV
 gp  hp
―
< 2.1 GeV
 pp  KL, KS
―
< 2.1 GeV
―
< 2.1 GeV
 # of coupled
channels
 gp  K+L, KS
Julia-Diaz, Lee, Matsuyama, Sato,
PRC76 (2007) 065201;
Julia-Diaz, et al., PRC77 (2008) 045205
HK, Nakamura, Lee, Sato
PRC88 (2013) 035209
Database for ANL-Osaka DCC analysis
πN  πN PWA from
SAID
πp 1ηN,
KΛ,observables
KΣ observables
Pseudoscalar
meson
photoproductions have
+ 15
!!
unpolarized
diff. crs. sec.
single pol.
beam-target
“(Over-) complete” experiments
has been achieved by CLAS for
KΛ and KΣ photoproductions !!!
HK, Nakamura, Lee, Sato
PRC88 (2013) 035209
beam-recoil
target-recoil
22,348 data of unpolarized & polarized observables to fit !!
γp  πN, ηp, KΛ, KΣ observables
γ p  π0 p reaction
Differential cross section (W = 1.08-2.1 GeV)
1.6 GeV
8ch DCC-analysis
[HK, Nakamura, Lee, Sato, PRC88 (2013) 035209]
1.9 GeV
previous 6ch DCC-analysis
(fitted to gN  pN data only up to W = 1.6 GeV)
[Julia-Diaz et al., PRC77 (2008) 045205]
γ p  π0 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) 053001.
(See arXiv:1108.5411 for comparison of conventions used in different analysis groups.)
γ p  π0 p reaction (3/3)
P
H
T
G
8ch DCC-analysis
[HK, Nakamura, Lee, Sato, PRC88 (2013) 035209]
hat E
Mass spectrum
Transition form factors and baryon structure
g*
e’
Measurement of p(e,e’π)N q& (q2 = -Q2)
p(e,e’ππ)N for 5 < Q2 < 10 (GeV/c)2. e
N
 JLab CLAS12 experiment
(E12-09-003)
γ*
N*,
N Δ*
N*, Δ*
N-N* electromagnetic transition form facctor
“partonic” picture
“hadronic” picture
meson clouds
“bare” baryon
meson
Q2 : small
baryon
？
Q2 : large
How effective d.o.f.’s describing baryon change with Q2 ?
Transition form factors and baryon structure
N  D (1232) M1 transition form factor
Transverse (transition) charge densities
light：＋charge
dark：０or －charge
Tiator et al., EPJST 198 (2011) 141
proton  proton
Bare
by [fm]
Full
by [fm]
Δ(1232)
at low Q2
Julia-Diaz et al,
PRC75 015205 (2007)
unpolarized density
bx [fm]
polarized in x-dir.
bx [fm]
proton  N*(1440)[Roper resonance]
Lattice QCD
Alexandrou et al.,
PRD83 (2011) 014501
unpolarized density
polarized in x-dir.
What we expect ELPH?
 Establish N*, Δ* spectrum in s1/2 = 1450 - 1750 MeV
 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)
ππN (~ 1220 MeV)、πηN(~ 1620 MeV)、
ηN (~ 1490 MeV)、KΛ (~ 1610 MeV)、
KΣ (~ 1680 MeV)、ωN (~ 1720 MeV)
Δ(1600) 3/2+
N(1685) ??
: Roper-like state of Δ baryon
mass is still uncertain (1450-1700 MeV)
: Seen in γd  (ηn) p
 The data we expect:
Double meson productions & Deuteron(neutron) target reactions
Our tasks
 Reducing computing time
（Computing time for double meson productions）
（Computing time for single meson productions）
= O(101)
Computation of cross section O(106-107) times are needed in χ2 -fitting.
 Extension to deuteron-target reactions
π, η, K, ππ,…
γ
d
+…
dσ/dΩ
γ “n”  π p
Σ
P
T
VERY PRELIMINARY !!
γ “n”  π0 n
Σ
dσ/dΩ
VERY PRELIMINARY !!
γ “n”  ηn
dσ/dΩ
Σ
Predicted results for γ “n”  K0Λ
ALL observables @ W = 1.8 GeV
Sensitive to F17 wave?
VERY PRELIMINARY !!
Double-pion production cross sections
(current situation)
Predicted πp  ππN cross sections
πNπΔ
πNπΔ, ρN,σN
πNπΔ, ρN
πNπΔ, σN
πNπΔ, ρN
8ch. model
[HK, PRC88 (2013) 045208]
6ch. model
[HK, Julia-Diaz, Lee,
Matsuyama, Sato,
PRC79 (2008) 025206]
Double-pion production cross sections
(current situation)
Predicted γp  ππN cross sections
γNπΔ, σN
γNπΔ, ρN,σN
8ch. model
[HK, Nakamura, Lee, Sato
PRC88 (2013) 035209]
6ch. model
γNπΔ, ρN
[HK, Julia-Diaz, Lee,
Matsuyama, Sato,
PRC80 (2009) 065203]
What we expect LEPS/LEPS2 ?
 Establish high-mass N*, Δ* mass spectrum
 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.
 The data we expect & our tasks
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）
Other topics
 meson productions with electron beam ??
e+d reactions are necessary for extracting Q2 dependence of
neutron target n-N* transition form factors.
Transition form factors are crucial not only for N* structure study, but also
for 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
QE
region
DIS
region
RES
region
Construction of unified neutrino reaction
model describing overlapping regions
between QE, RES, and DIS regions !!
http://nuint.kek.jp
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.)
T2K
CP phase & mass
hierarchy studies
with atmospheric exp.
[ arXiv:1303.6032]
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)
8ch DCC-analysis
[HK, Nakamura, Lee, Sato, PRC88 (2013) 035209]
P
T
γ p  π+ n reaction (3/3)
8ch DCC-analysis
[HK, Nakamura, Lee, Sato, PRC88 (2013) 035209]
hat E
G
H
γ p  η p reaction (1/2)
8ch DCC-analysis
[HK, Nakamura, Lee, Sato, PRC88 (2013) 035209]
DCS
γ p  η p reaction (2/2)
8ch DCC-analysis
[HK, Nakamura, Lee, Sato, PRC88 (2013) 035209]
Σ
T
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
Cx’
Ox’
Cz’
Oz’
8ch DCC-analysis
[HK, Nakamura, Lee, Sato, PRC88 (2013) 035209]
γ p  K+ Σ0 reaction
DCS
P
Cx’
Cz’
Σ
8ch DCC-analysis
[HK, Nakamura, Lee, Sato, PRC88 (2013) 035209]
γ p  K0 Σ+ reaction
8ch DCC-analysis
[HK, Nakamura, Lee, Sato, PRC88 (2013) 035209]
DCS
P
Σ
質量スペクトル

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