Dynamical Coupled-Channels Approach for Single- and Double- - PowerPoint Presentation

Slide1

Dynamical Coupled-Channels Approach for Single- and Double-Pion Electroproductions: Status and Plans

Hiroyuki KamanoResearch Center for Nuclear Physics (RCNP)Osaka University

EmNN

*2012 Workshop @ USC, USA, August 13-15, 2012Slide2

Outline

1. Background and motivation for N* spectroscopyANL-Osaka Dynamical Coupled-Channels (DCC) approach for N* spectroscopy

3.

Status and plans for single- and double-pion

electroproduction reactions

4.

Related hadron physics program at J-PARCSlide3

Background and motivation for

N* spectroscopy(1 / 4)Slide4

N*

spectroscopy :

Physics of broad & overlapping resonances

Δ

(1232)

Width:

a few hundred

MeV.

Resonances are

highly overlapping

in energy except

D

(1232).

Width:

~10

k

eV

to

~ 10 MeV Each resonance peak is clearly separated.

N* : 1440, 1520, 1535, 1650, 1675, 1680, ...

D

: 1600, 1620, 1700,

1750, 1900,

…Slide5

Hadron spectrum and reaction dynamics

Various static hadron models have been proposed to

calculate

hadron

spectrum

and

form

factors.

In reality,

excited hadrons

are

“unstable”

and can exist

only as resonance states

in hadron reactions.

Quark models, Bag models, Dyson-Schwinger approaches, Holographic QCD,…

Excited hadrons

are treated as

stable particles.  The resulting masses are real.

What is the role of

reaction dynamics

in

interpreting

the

hadron spectrum, structures, and dynamical origins

??

“Mass

”

becomes complex !! “pole mass”

u

u

d

Constituent quark model

N*

bare

state

meson cloud

“

molecule-like”

states

core (bare state) + meson cloudSlide6

ANL-Osaka Dynamical Coupled-Channels (DCC) approach for N* spectroscopy

(2 / 4)Slide7

Objectives and goals:

Through the

comprehensive analysis

of world data

of

p

N

,

g

N

, N(e,e’) reactions

, Determine N* spectrum (pole masses) Extract N* form factors

(e.g., N-N*

e.m. transition form factors) Provide reaction mechanism information

necessary for interpreting N* spectrum, structures and dynamical origins

ANL-Osaka Dynamical Coupled-Channels Approach for N*

Spectroscopy

Spectrum, structure,…

of N* states

Q

C

D

Lattice QCD

Hadron Models

Analysis Based on Reaction Theory

Reaction Data

“Dynamical coupled-channels model of meson production reactions”

A. Matsuyama, T. Sato, T.-S.H. Lee Phys. Rep. 439 (2007) 193Slide8

Partial wave (LSJ)

amplitudes

of a

 b reaction

:

Reaction channels:

Transition Potentials:

coupled-channels effect

Exchange potentials

bare N* states

For details see Matsuyama, Sato, Lee, Phys. Rep. 439,193 (2007)

Z-diagrams

Dynamical coupled-channels (DCC) model for

meson production reactions

Meson-Baryon

Green functions

Stable channels

Quasi 2-body channels

N

p

D

p

D

p

p

p

r, s

r, s

N

N

p, r, s, w,..

N

N,

D

s-channel

u-channel

t-channel

contact

Exchange potentials

Z-diagrams

Bare N* states

N*

bare

D

p

N

p

p

D

D

N

p

r,

s

Can be related

to hadron

states of the

static hadron

models

(

quark

models, DSE,

etc

.)

excluding

meson-baryon continuum

.

core

meson cloud

meson

baryon

Physical N*s will be a “mixture” of the two pictures:Slide9

DCC analysis (2006-2009)

p

N



p

N

: Analyzed to construct a hadronic part of the model

up

to W = 2

GeV

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

p

N  h N : Analyzed to construct a hadronic part of the model

up to W = 2

GeV

Durand, Julia-Diaz, Lee, Saghai, Sato, PRC78 025204 (2008) p N  p p

N : Fully dynamical coupled-channels calculation up to W = 2 GeV Kamano, Julia-Diaz, Lee, Matsuyama, Sato, PRC79 025206 (2009)

g

(*)

N 

p

N :

Analyzed to construct a E.M. part of the model

up to W = 1.6 GeV and Q2 = 1.5 GeV2 (

photoproduction) Julia-Diaz, Lee, Matsuyama, Sato, Smith, PRC77 045205 (2008) (electroproduction) Julia-Diaz, Kamano, Lee, Matsuyama, Sato, Suzuki, PRC80 025207 (2009) g N 

p

p

N : Fully dynamical coupled-channels calculation up to W = 1.5 GeV Kamano, Julia-Diaz, Lee, Matsuyama, Sato, PRC80 065203 (2009)

Extraction of N* pole positions & new interpretation on the dynamical origin of P11 resonances Suzuki, Julia-Diaz, Kamano, Lee, Matsuyama, Sato, PRL104 065203 (2010)

Stability and model dependence of P11 resonance poles extracted from pi N  pi N data Kamano,

Nakamura, Lee, Sato, PRC81 065207

(2010) Extraction of g

N

 N* electromagnetic transition form factors Suzuki, Sato, Lee,

PRC79 025205 (2009);

PRC82 045206 (2010)

Hadronic part

Electromagnetic part

Extraction of N* parameters

g

N

,

p

N

,

h

N

, pD, rN, sN coupled-channelscalculations were performed.Slide10

Dynamical origin of

nucleon resonances

Pole positions and dynamical origin of P11 resonances

Suzuki, Julia-Diaz, Kamano, Lee, Matsuyama, Sato, PRL104 065203 (2010

)

pole A:

pD

unphys. sheet

pole B:

pD

phys. sheet

Double

-pole nature

of the

Roper

is found

also from

completely different approaches

:

Eden, Taylor, Phys. Rev. 133 B1575 (1964)

Multi

-channel

reactions can

generate

many

resonance poles

from a

single

bare

state !!

For evidences

in hadron and nuclear

physics, see

e.g., in Morgan and Pennington, PRL59 2818 (1987)Corresponds to hadron states from static hadron modelsSlide11

N-N* transition form factors at

resonance poles

Julia-Diaz

, Kamano, Lee, Matsuyama, Sato

, Suzuki PRC80 025207

(

2009)

Suzuki, Sato, Lee,

PRC82

045206 (2010)

Real part

Imaginary part

Nucleon - 1

st

D13

e.m

. transition form factors

Coupling to meson-baryon continuum states

makes

N* form factors

complex

!!

Fundamental nature of

resonant particles

(decaying states)

Extracted from analyzing the

p(

e,e’

p

)N data from CLASSlide12

Dynamical coupled-channels (DCC) analysis



p





N

g

p





N

p  hN

gp

 h

p pp  KL, KS

gp  K+L, KS

2006

- 2009

6

channels

(

g

N,

pN,hN,pD,rN,sN)< 2 GeV< 1.6 GeV< 2

GeV

――

―

2010 - 20128

channels (gN,pN,hN,

pD,rN,sN,K

L,KS)< 2.1 GeV

< 2

GeV< 2 GeV< 2

GeV

< 2.2 GeV< 2.2 GeV

# of

channels

Fully combined

analysis of

p

N

,

gN

 N , hN ,

KL, KS reactions !! Kamano, Nakamura, Lee, Sato(2012)(more than 20,000 data points to fit)Slide13

Partial wave amplitudes of pi N scattering

8ch DCC-analysis

(Kamano, Nakamura, Lee, Sato

2012)

6ch DCC-analysis

(fitted to

p

N



p

N

data

only

)

[PRC76 065201 (2007)]

Real part

Imaginary partSlide14

Partial wave amplitudes of pi N scattering

8ch DCC-analysis

(Kamano, Nakamura, Lee, Sato

2012)

6ch DCC-analysis

(fitted to

p

N



p

N

data

only

)

[PRC76 065201 (2007)]

Real part

Imaginary partSlide15

π

- p  ηn reactions

Analyzed data up to

W = 2

GeV

.

p

-

p



h

n

data are selected

according to

Durand et al. PRC78 025204.

Kamano, Nakamura, Lee, Sato, 2012Slide16

πN  KY reactions (1/2)

Kamano, Nakamura, Lee, Sato, 2012

π

-

p

 K

0

Σ

0

π

-

p

 K

0Λ

π

+p  K+

Σ+Slide17

πN  KY reactions (2/2)

Kamano, Nakamura, Lee, Sato, 2012

π

-

p

 K

0

Σ

0

π

-

p

 K

0Λ

π

+p  K+

Σ+Slide18

γp

 πN reactions(1/2)γp

 π

+

n

γp

 π

0

p

Kamano, Nakamura, Lee, Sato, 2012Slide19

γp

 πN reactions(2/2)γp

 π

+

n

γp

 π

0

p

Kamano, Nakamura, Lee, Sato, 2012Slide20

γp  ηp

reactionKamano, Nakamura, Lee, Sato, 2012Slide21

γp  K+

Σ0, K0Σ+ reactions

Kamano, Nakamura, Lee, Sato, 2012

γp



K

+

Σ

0

γp

 K

0

Σ

+Slide22

γp  K+

Λ reaction (1/4)Kamano, Nakamura, Lee, Sato, 2012Slide23

γp  K+

Λ reaction (2/4)Kamano, Nakamura, Lee, Sato, 2012Slide24

γp  K+

Λ reaction (3/4)Kamano, Nakamura, Lee, Sato, 2012Slide25

γp  K+

Λ reaction (4/4)Kamano, Nakamura, Lee, Sato, 2012Slide26

Status and plans for single- and double-pion electroproduction rections

(3 / 4)Slide27

Status and plans for analysis of electroproduction reactions

6-channel (2006-2009) 8-channel (2010-2012)

γp

 πN

γp

 ππN

ep

 e’πN

ep

 e’ππN

W < 1.6

GeV

(the data analyzed)

W < 1.6

GeV(cross sections predicted)W < 1.6 GeV

, Q2 < 1.5 (GeV/c)

2(the data analyzed)W < 2

GeV(the data analyzed)Not yet doneNot yet done

Not yet done

[Plan 1]: After completing 8-ch analysis,

immediately proceed to the analysis

of

CLAS p(

e,e

π)N data

and extract

N-N* e.m. transition form factorsup to Q2 ~ 4 (GeV/c)2.

[Plan 2]: After Plan 1,

we can give

prediction for p(e,e

ππ)N cross sections.[Combined analysis of p(e,eπ)N and p(e,eππ)N will be a long term project.]

VERY preliminary results available(Q2 = 0 point)(nonzero Q2)Slide28

γp  ππN calculation with 8-ch. DCC model

Prediction for

γ

p



ππ

N

t

otal cross sections (not yet included in the fit)

8-ch. DCC Full

(

Kamano

, Nakamura, Lee, Sato 2012)

6

-ch. DCC Full [PRC80 065203 (2010)]

8-ch. DCC

Nonresonant

only6-ch. DCC Nonresonant

onlyVERY PRELIMINARY !!Slide29

Related

hadron physics program at J-PARC

(4

/

4)Slide30

Hadron physics program at J-PARC

WG

on

“Hadron physics with

high-momentum beam line

at J-PARC”

Currently J-PARC has

high-momentum

proton (< 30

GeV

/c)

and pion (~ 15 GeV

/c) beams.  Now considered as one of the highest priority projects at KEK/J-PARC from April 2013.

Hadron

properties in nuclear mediumpQCD, partonic

structure of nucleon and nucleiCharmed-hadron physicsExotic hadrons and nuclei

N* physics (N*, Δ*, ...)

High-energy spin physicsShort-range

NN correlationsTransition from hadron to quark degrees of freedomExclusive processes (GPD, quark counting, ...)Quark/hadron interactions in nuclear medium (parton-energy loss, color

transparency)J/ψ production mechanisms and its interactions in nuclear mediumPion distribution amplitude, hadron-transition distribution amplitudesIntrinsic charm and strange … AND MORE TO COME!!Slide31

πN  ππN: “Critical missing piece”

in N* spectroscopy.Measurement of πN  ππN & KY in high-mass N* region (K. Hicks, K. Imai et al.)

The idea originates from “US-Japan Joint

Workshop on Meson Production Reactions at

Jefferson Lab and J-PARC” Hawaii, Oct. 2009.



There is

NO

practical data that can be used for partial wave analysis

above W > 1.5

GeV

.



Above W > 1.5

GeV

, πN  ππN becomes the

dominant process of the πN reactions.

Most of the N*s decay dominantly

to the ππN channel.

Hadron physics program at J-PARC

The current N* mass spectrum might receive significant modificationsand even new N* states might be discovered by the combined analysisincluding this new πN  ππN data !! Slide32

Hadron physics program at J-PARC

Measurement of forward p(π,ρ)X, p(π, K*)X reactions (T. Ishikawa, T. Nakano et al.)

p

virtual π

N*, Δ* (slow)

Q

2

high-p π

ρ

(fast)

p

virtual K

Y

* (slow)

high-p π

K* (fast)

Can be

used for extracting

N-N*

axial

transition form factors

Can access to

Λ

(1405) region

below KN threshold.

Could be used for extracting

strangeness changing

axial

form factors.

Crucial for constructing reliable

neutrino-nucleon/nucleus

reaction models

in resonance and DIS region

.  Collaboration@J-PARC Branch of KEK Theory Center [Y. Hayato, M. Hirai, H. Kamano

, S. Kumano, S. Nakamura, K. Saito, M.

Sakuda, T. Sato] (http://j-parc-th.kek.jp/html/English/e-index.html)

Q2Slide33

Summary

;



p





N

g

p





N

p  hN

gp

 h

p pp  KL, KS

gp  K+L, KS

2006

- 2009

6

channels

(

g

N,

pN,hN,pD,rN,sN)< 2 GeV< 1.6 GeV< 2

GeV

――

―

2010 - 20128

channels (gN,pN,hN,

pD,rN,sN,KL

,KS)< 2.1 GeV< 2

GeV

< 2 GeV< 2 GeV

< 2.2

GeV< 2.2 GeV

# of

channels

Summary

After completing

the combined analysis of πp,

γp

 πN, ηN, KΛ, KΣ reactions, immediately proceed to

the analysis of CLAS p(

e,eπ)N data and extract N-N* e.m. transition form factors up to Q2 ~ 4 (

GeV/c)2.Combined analysis of p(e,e

π)N and p(e,eππ)N is considered as a long term project in future. [Combined analysis of p(e,e’π)N, p(e,e’η)p, p(e,e’K)Y could be done quickly.]With the new 8-channels model, nucleon resonance parameters(mass spectrum, decay widths, etc.) are being investigated.(As presented in T. Sato’s talk)Slide34

back upSlide35

P

henomenological prescriptions of constructing conserved-current matrix elements

As commonly done in

practical

calculations in nuclear and particle physics,

currently

we take

a phenomenological prescription to construct conserved

current matrix elements

[T. Sato, T.-S. H. Lee, PRC60 055201 (2001)]

:

:

Full e.m. current matrix elements obtained by solving DCC equations

: photon momentum

: an arbitrary four vector

A similar prescription is applied, e.g., in

Kamalov and Yang, PRL83, 4494 (1999).

There are also other prescriptions that enable practical calculations satisfying

current conservation or WT identity: Gross and Riska, PRC36, 1928 (1987)Ohta, PRC40, 1335 (1989)

Haberzettl, Nakayama, and Krewald, PRC74, 045202 (2006).Slide36

Since the late 90s, huge amount of

high precision data of

meson

photo-production reactions

on the nucleon target has been reported

from

electron/photon beam facilities.

JLab

, MAMI, ELSA,

GRAAL

,

LEPS/SPring-8, …

Experimental developments

E.

Pasyuk’s

talk at

Hall-B/EBAC

meeting

Opens a great opportunity to make quantitative study of the N* states !! Slide37

N* states and PDG *s

?

?

?

?

?

Arndt, Briscoe, Strakovsky, Workman PRC 74 045205 (2006)

Most of the N*s were

extracted from

Need

comprehensive analysis

of

channels !!

From PDG 2010Slide38

Note: Some freedom exists on the definition of partial width

from the residue of the amplitudes.

Width of N* resonances

(Current status

)

Kamano, Nakamura, Lee, Sato, 2012Slide39

Spectrum of N* resonances

(Current status)

Real parts of N* pole

value

s

L

2I 2J

PDG

Ours

N* with 3*,

4*

18

16

N* with 1*, 2*

5

PDG 4*

PDG 3*

Ours

Kamano, Nakamura, Lee, Sato, 2012Slide40

γp

 πN reactions

6ch

DCC-analysis [PRC77 045205 (2008

)]

(fitted to

g

N



p

N

data

up to 1.6 GeV

)

Angular distribution

Photon asymmetry

1137 MeV

1232 MeV

1334 MeV

1462 MeV

1527 MeV

1617 MeV

1729 MeV

1834 MeV

1958 MeV

1137 MeV

1232 MeV

1334 MeV

1462 MeV

1527 MeV

1617 MeV

1729 MeV

1834 MeV

1958 MeV

8ch DCC-analysis

Kamano, Nakamura, Lee, Sato

2

012Slide41

Single pion electroproduction

(Q

2

> 0)

Fit to the structure function data (~ 20000) from CLAS

Julia-Diaz, Kamano, Lee, Matsuyama, Sato, Suzuki, PRC80 025207 (2009)

p (e,

e’

p

0

) p

W

<

1.6

GeV

Q

2

<

1.5

(GeV/c)

2

is determined

at each Q

2

.

N*

N

g

(q

2

= -Q

2

)

q

N-N*

e.m

. transition

form factorSlide42

Single pion electroproduction (Q

2 > 0)

Julia-Diaz, Kamano, Lee, Matsuyama, Sato, Suzuki, PRC80 025207 (2009)

p (e,

e’

p

0

) p

p (e,

e’

p

+

) n

Five-fold differential cross sections at Q

2

= 0.4 (GeV/c)

2Slide43

Data handled with

the help of R. Arndt

pi N

 pi

pi

N reaction

Parameters used in the calculation are from

p

N



p

N analysis.

Kamano, Julia-Diaz, Lee, Matsuyama, Sato, PRC79 025206 (2009)

Full result

Phase space

Full result

W (GeV)

s

(mb)

C. C. effect off