neutrino-induced meson production model for neutrino oscillation experiments satoshi nakamura...
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Neutrino-induced meson production model
for neutrino oscillation experiments
Satoshi NakamuraNuclear Theory Group
Contents
★ Introduction nN scattering for neutrino exp.
★ Dynamical coupled-channels (DCC) model for
, gN pN
, , , , pN ppN hN KL KS
★ Application of DCC model to
nN , , , , pN ppN hN KL KS
Near detector
Far 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
LBL
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)
Dealing with multi-channel reaction
Unitary coupled-channel model needs to be developed
Unitarity is missing in previous models Important 2 p production model is missing Previous models for K and h production are not well tested by data
Problems
★ Dynamical coupled-channels model for , gN pN , , , pN ppN hN
, KL KS
★ Application to nN , , , , pN ppN hN KL KS
Dynamical Coupled-Channel model for
, gN pN , , , , pN ppN hN KL KS
Kamano, Nakamura, Lee, Sato
Coupled-channel unitarity is fully taken into acount
DCC analysis of meson production data
Fully 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 points
Kamano, Nakamura, Lee, Sato, 2012
Vector current (Q2=0) for 1 p
Production is well-tested by data
Kamano, Nakamura, Lee, Sato, 2012
Vector current (Q2=0) for h
Production is well-tested by data
Kamano, Nakamura, Lee, Sato, 2012
Vector current (Q2=0) for K
Production is well-tested by data
Short Summary
• DCC 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-scattering
• Check out JPS monthly magazine next (X 2,3) months for a review
PCAC-based application of DCC model to
forward nN , , , , pN ppN hN KL KS
Kamano, Nakamura, Lee, Sato, PRD 86, 097503 (2012)
Objectives
Set a starting point for full dynamical model
… we study only Q2=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
Results
SLpN
ppN KShN
KL
Prediction based on model well tested by data
pN dominates for W ≤ 1.5 GeV
ppN becomes comparable to pN for W ≥ 1.5 GeV
Smaller contribution from hN and KY O(10-1) - O(10-2)
Comparison with Rein-Sehgal model
Lower D peak of RS model
RS overestimate in higher energy regions (DCC model is tested by data)
Comparison with Rein-Sehgal model
Summary
DCC model for forward nN , , , , pN ppN hN KL KS via
PCAC
Prediction based on model well tested by data
ppN 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 difference
Full development of dynamical axial current is underway
BACKUP
Formalism
Cross section for nN X ( X = , , , , pN ppN hN KL KS )
q 0
Q20
CVC & PCAC
LSZ & smoothness
Finally spNX is from our DCC model
Previous models for n-induced 1p 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)
Partial wave amplitudes of pi N scattering
Kamano, Nakamura, Lee, Sato, 2012
Previous model (fitted to pN pN data only)[PRC76 065201 (2007)]
Real part
Imaginary part
Eta production reactions
Kamano, Nakamura, Lee, Sato, 2012
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, 2012
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 πN reactions. (same applied to n-scattering)
Model for nN ππN will be essetial piece in MC
πN ππN data are essential to develop nN ππN model
Please support the proposal !
F2 from RS model
F2 from RS model
Spectrum of N* resonances
Real parts of N* pole values
L2I 2J
PDG Ours
N* with 3*, 4* 1816
N* with 1*, 2* 5
PDG 4*
PDG 3*
Ours
Kamano, Nakamura, Lee, Sato ,2012
SL model applied to -n nucleus scattering
1 p production
Szczerbinska et al. (2007)
SL model applied to -n nucleus scattering
coherent p production
g + 12C p0 + 12C nm + 12C m- + p0 + 12C
Nakamura et al. (2010)
Dealing with multi-channel reaction
e.g., n-induced K production
Tree-level models
DS=0 : Adera et al., (2010)
DS=1 : Rafi Alam et al., (2010), (2012)
DCC model for , gN pN , , , pN hN KL KS
reactionsFor 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-channels
Resonance region
D
2nd 3rd
Many nucleon resonances in 2nd and 3rd resonance region
(MeV)