Neutrino-induced meson production model - PowerPoint Presentation

Slide1

Neutrino-induced meson production model for neutrino oscillation experiments

Satoshi Nakamura

Nuclear Theory GroupSlide2

Contents

Introduction

nN

scattering

for neutrino exp.

Dynamical coupled-channels (DCC) model for

gN

,

pN



pN

,

ppN

,

hN

, KL, KS

A

pplication

of DCC model to

nN



pN

,

ppN

,

hN

, KL, KS

Slide3

Near detectorFar detector

Comparison



oscillation



q, Dm2

q13 ≠ 0 (Daya-Bay, RENO, T2K, MINOS, Double-Chooz)

Next-generation exp.  leptonic CP, mass hierarchy

n-

nucleon (nucleus) scattering needs to be understood more precisely

Wide kinematical region with different characteristic Combination of different expertise is necessary

Collaboration at J-PARC Branch of KEK Theory Center http://j-parc-th.kek.jp/html/English/e-index.html

Neutrino flux  # of events of n-nucleus interaction

n-nucleus cross section 

LBLSlide4

Many nucleon resonances in 2nd and 3rd resonance region

Resonance region

D

2nd

3rd

Not

only 1

p

production but also …

Multi-channel reaction

2p production is comparable to 1p

 h,

K productions (background of proton decay exp.) (MeV)

(Data)Slide5

Dealing with multi-channel reactionUnitary coupled-channel

model needs to be developed

Unitarity

is missing in previous models

Important

2

p production model is missingPrevious models for K and

h production are not well tested by dataProblems Dynamical coupled-channels model for

gN, pN 

pN,

ppN, hN, KL, KS

Application to nN

 pN, ppN, hN

, KL, KS Slide6

Dynamical Coupled-Channel model for

gN

,

pN



pN, ppN, hN

, KL, KSKamano, Nakamura, Lee, SatoSlide7

Coupled-channel

unitarity

is fully taken into

acount

Slide8

DCC analysis of meson production dataFully combined

analysis of

gN

,

pN

 pN, hN

, KL, KS (W ≤ 2.1 GeV)Fitting ~380 parameters (N* mass, N*

 MB couplings, cutoffs) to ~ 20,000 data pointsSlide9

Kamano, Nakamura, Lee, Sato, 2012

Vector current (Q

2

=0) for 1

p

Production

is well-tested by dataSlide10

Kamano

, Nakamura, Lee, Sato, 2012

Vector current (Q

2

=0) for

h

Production

is well-tested by dataSlide11

Kamano

, Nakamura, Lee, Sato, 2012

Vector current (Q

2

=0) for

K

Production is well-tested by dataSlide12
Slide13

Short SummaryDCC

model for

gN

,

pN

 pN, ppN, hN, KL, KS developed

Model has been extensively tested by data  reliable vector current to be applied to n-

scatteringCheck out JPS monthly magazine next (X 2,3) months for a reviewSlide14

PCAC-based application of DCC model to forward

nN



pN, ppN, hN, KL,

KSKamano, Nakamura, Lee, Sato, PRD 86, 097503 (2012)Slide15

Objectives

Set a starting point for full dynamical

model

… we study only

Q

2

=0 here.Relative importance of different channels (pN, ppN, KY..)

Comparison with Rein-Sehgal model (in most MC code)nN reaction, vector and axial currents contribute.For Q2=0 , only survives.PCAC relation, is used.nN

reaction amplitude is related to pN reaction amplitude

PCAC-based calculation of

nN

reaction Slide16

Results

SL

p

N

pp

N

KS

hNKL

Prediction based on model well tested by data

pN

dominates for W ≤ 1.5 GeV

ppN becomes comparable to

pN for W ≥ 1.5 GeVSmaller contribution

from hN and K

Y O(10-1) - O(10-2)Slide17

Comparison with Rein-Sehgal model

Lower

D

peak of RS model

RS overestimate in higher energy regions

(DCC model is tested by data)Slide18

Comparison with Rein-Sehgal modelSlide19

SummaryDCC

model

for forward

nN



pN, ppN, hN

, KL, KS via PCAC Prediction based on model well tested by datappN

comparable to pN for

W ≥ 1.5 GeV (first

nN 

ppN)

First data-based prediction for nN  hN

, KY Comparison with Rein-Sehgal

model :Significant differenceFull development of dynamical axial current is

underwaySlide20

BACKUPSlide21

Formalism

Cross section for

nN



X ( X = pN, ppN,

hN, KL, KS )q 0

Q

2

0

CVC & PCAC

LSZ & smoothness

Finally spN

X is from our DCC modelSlide22

Previous models for n

-

induced 1

p

production in resonance region

Rein et al. (1981), (1987) ; Lalalulich et al. (2005), (2006)

Hernandez et al. (2007), (2010) ; Lalakulich et al. (2010)Sato, Lee (2003), (2005)

resonant only + non-resonant (tree-level)

+

rescattering (p N unitarity)Slide23

Partial wave amplitudes of pi N scattering

Kamano

, Nakamura, Lee, Sato, 2012

Previous model

(fitted to

p

N



p

N data

only

)[PRC76 065201 (2007)]

Real part

Imaginary partSlide24

Eta production reactions

Kamano, Nakamura, Lee, Sato

, 2012Slide25

KY production reactions

1732 MeV

1845

MeV

1985

MeV

2031

MeV

1757

MeV

1879

MeV

1966

MeV

2059

MeV

1792

MeV

1879

MeV

1966

MeV

2059

MeV

Kamano, Nakamura, Lee, Sato

, 2012Slide26

J-PARC proposalπN



ππN

in high-mass N*

region

(K. Hicks, K. Imai et al.)

 There is

NO practical data that can be used for testing models for πN  ππN above W > 1.5 GeV. For W > 1.5 GeV, πN

 ππN becomes the dominant process of the π

N reactions. (same applied to n-scattering)

Model for

nN  ππN will be essetial

piece in MCπN  ππN data are essential to develop nN  ππN

model Please support the proposal !Slide27

F2 from RS modelSlide28

F2 from RS modelSlide29

Spectrum of N* resonances

Real parts of N* pole

value

s

L

2I 2J

PDG

Ours

N* with 3*, 4*1816

N* with 1*, 2*

5

PDG 4*

PDG 3*

Ours

Kamano, Nakamura, Lee, Sato

,2012Slide30

SL model applied to n-nucleus scattering

1

p

production

Szczerbinska

et al. (2007)Slide31

SL model applied to n-nucleus scattering

coherent

p

production

g

+

12C

 p0 + 12C nm +

12C  m

- + p

0 + 12C

Nakamura et al. (2010)Slide32

Dealing with multi-channel reactione.g.,

n

-induced

K

production

Tree-level models

DS=0 : Adera et al., (2010)

DS=1 : Rafi Alam et al., (2010), (2012) Slide33

DCC model for gN

,

pN



pN, hN, KL, KS reactions

For analyzing data to identify nucleon resonances (Baryon spectroscopy)* Well-established meson-exchange mechanism for meson-baryon interactions

* Description of nucleon resonance (N*)

g , p

N

B

M

N*

*

Unitarity



gN

,

pN

,

hN

,

ppN

(

pD

,

rN

,

sN

), KL

, KS

coupled-channelsSlide34
Slide35

Resonance region

D

2nd

3rd

Many nucleon resonances in 2

nd

and 3

rd resonance region

(MeV)