Study of three‐nucleon forcewith a new experiment of
a proton‐deuteron break‐up reaction
Yuya Akazawa, M. Fujita, R. Honda1, M. Ikeda, H. Kanauchi, K. Kobayashi1, T.Koike,
K. Miki, K. Miwa, Y. Nakada1, S. Ozawa, Y. Sasaki, K. Sekiguchi, H. Tamura
Department of Physics, Tohoku University, Sendai , Japan1Department of Physics, Osaka University, Osaka, Japan
NSMAT2016
Contents
Introduction• 3NF study ← p‐d break-up reaction• Detector system “CATCH”
p‐d reaction experiment @ CYRIC• Experimental condition• Simulated result• Preparation status
Summary
3NF and Neutron star• Importance of Three-Nucleon Force (3NF) for NS
Model dependent
A. Akmal, et al., PRC58, 1804 (1998)
neutron matter
2NF : realistic nuclear potential ⇐ 3000~4000 NN scattering experimental data
⇒more experimental data needed for 3NF, YN, YY
ρ0
Study of 3NF by a p‐d break‐up reaction
『p-d break-up reaction』
J. Kuros´-Z˙ołnierczuk et al., PHYSICAL REVIEW C66, 024003 (2002)
S MeV
[mb
/(sr2・
MeV
)]
2NN
One of the probes to revealthe nature of three-nucleon force (3NF).
p1
p2n
Φ12
p beam
p1
p2
n
(E1,θ1)
(E2,θ2)
beam
p+d→p+p+n
d target
θ1
θ2 2NF+3NF
Ebeam = 65 MeV
From side
From back
S : correlation between E1 and E2
S (MeV)
Study of 3NF by a p‐d break-up reactionSome observables
・Energy correlation dependence・Reaction angular dependence (θ1,θ2)・Φ12 dependence
(θ1,θ2) dependence Φ12 dependence
Detector with a large angle acceptance for multi-particles is required
(θ1,θ2)=(15°,15°)Φ12=180°
(25°,15°) (30°,15°)
(25°,20°) (30°,20°)
※ θ±1°, Φ±5°
Φ12=40° Φ12=60°
Φ12=120°
Φ12=140°
S. Kistryn et al., Phys. Lett. B641, 23 (2006).
S (MeV)
S. Kistryn et al., Phys. Rev. C68, 054004 (2003).
2NF2NF+3NF
2NF
2NF+3NF
Experimental data at 130 MeV d beam
As the first step, we will take data with an 80 MeV p beam.
Current experimental data of p‐d reactions
⇒ new data points with our new detector system
80 MeVMeV/nucleon beam
80 MeV
関口さん
Courtesy of K. Sekiguchi [1] K. Bodek et al., Few Body Syst. 30, 65 (2001)[2] St. Kistryn, et al., Phys. Rev. C 68, 054004 (2003)[3] H. Mardanpour, et al., Nucl. Phys. A 790 (2007), p. 426c
etc.
RIKEN, RCNP, KVI, IUCF
next page
“CATCH”We will use this detector system for the p-d experiment.
Advantages・Large acceptance (∵surrounding the target)・Many sets of (θ1,θ2,Φ12)
in one experimental setup・Multiple particle detection・Particle ID (p/d/μ・π)
Cylindrical Fiber Tracker・surrounding a target ・8 layers of scintillation fibers・three dimensional tracking⇒measure the scattering angle (σ=1°)
and the energy deposit (σ=20%@1MeV)
BGO calorimeter・surrounding the CFT・24 BGO crystals (30×25×400mm3) are used ⇒measure the kinetic energy
(σ=1%@80MeV)
Cylindrical Active Tracker and Calorimeter system for Hyperon-proton scattering
Production finished soon
“CATCH”We will use this detector system for the p-d experiment.
Advantages・Large acceptance (∵surrounding the target)・Many sets of (θ1,θ2,Φ12)
in one experimental setup・Multiple particle detection・Particle ID (p/d/μ・π)
Cylindrical Active Tracker and Calorimeter system for Hyperon-proton scattering
Production finished soond
p
E(BGO) [MeV]
ΔE
(Fib
er)
[M
eV
]
Cosmic ray
Prototype results of pp, pC scattering
experiment
p-d experiment @ CYRIC• Experimental condition• Simulated result
• Preparation status
p‐d reaction experiment with CATCH
Measurement of dσ/dΩ of the p-d elastic scattering and break-up reaction⇒ new data for 3NF
Purpose
Experimental setup To be performed at CYRIC, Tohoku Univ. in January 2017
are
mea
sure
d .
Elastic scattering
p beam80 MeV
d’
p’
CFT
BGO calorimeter
D2 gas target300 mm(t)
Commissioning of the CATCH system
p beam80 MeV
p
p
n
Break-up reaction
Event identification for elastic scattering and break-up reaction
Simulation
θ [deg.]
E(C
FT+B
GO
) [M
eV]
Simulated result (pd elastic)
Ed’(θ)
Kinematically calculated Ep’(θ)
Simulation
pd散乱も80 MeVのデータは未測定⇒②-3
シミュレーション結果(pd break-up)
beam
Event generation: p-d elastic scattering kinematics. Detector: CATCH configuration
※Energy resolution is taken into account.
Event ID
p and d are clearly separated.
Simulated result (pd elastic)
Total E [MeV]
CFT
ΔE
[MeV
]
p
d
Particle ID
Simulation: p‐d elastic scattering
Identification of elastic scattering events using the kinematically calculated energy.
p’
d’
pd散乱も80 MeVのデータは未測定⇒②-3
シミュレーション結果(pd break-up)
beam
dσ/dΩ can be obtained as a function of S
for various combinations of (θ1,θ2,Φ12)
Simulated result
Missing Mass
reconstructed fromthe two protons
break-up reaction can be identified using Missing Mass of n
Ep1 vs Ep2Simulated result (pd break-up)
Missing Mass (Event ID)
S axis
Ep1 [MeV]
E p2
[MeV
]Uniquely determined correlation
p_{low E} can’t be tracked.
※threshold can be decreased
Selecting (θ1,θ2,Φ12)
θ1=55±2.5°θ2=60±2.5°Φ=180±10°
Event generation: p-d break-up reaction
for several combinations of (θ ,θ ,E ,E
p
p
n
pd→ppXMassX
S MeV
Simulation: p‐d break-up reaction
Energy acceptance:higher than 20 MeV for both Ep1 & Ep2
Status of CATCHBGO
Completed an assembly of CFT last week !!
BGO calorimeter is ready
Half part(14 crystals)
400mm400mm
4 straight +4 spiral layers
CFT
Angular resolution σθ≃1°(prototype)Efficiency ≃ 98% (3rd straight layer)
≃ 96%(3rd spiral layer)
Energy resolution σE≃ 1%for 80 MeV p
Satisfactory performance
Expected performance
Two systems will be combinedinto CATCH next month
p
p
n
400 mm
beam
p’
CATCH the new horizon
To be studied after commissioning of CATCH
Λp scattering
3NF
The same method as ∑p scattering except for
p-d, p-3He, etc…elastic scattering & break-up
Baryon-Baryon interactionΣp scattering
3NF (T=3/2)
Originally designed to be used for this experiment in J-PARC
p-d reaction experiments with CATCH is just a starting point
CATCH + spectrometers
Cylindrically
Active
Tracker and
Calorimeter system for
Hyperon-proton
scattering experiment
• 3NF study for neutron star- p-d elastic scattering and break-up reaction are one of the probes.- dσ/dΩ of p-d reaction at 80 MeV beam will be new data.
• New detector system CATCH- Suitable for this experiment because of its large acceptance- Consisting of a Cylindrical Fiber Tracker and BGO calorimeters- The first operation and application
• Simulation- p/d are clearly discriminated. - p-d elastic scattering & break-up reaction are identified from the
kinematics and missing mass
• Preparation- CATCH will be all constructed next month.
⇒ The experiment will be performed in Jan. 2017
Summary
• CATCH specification z acceptance = 400 [mm]
Energy acceptance 5 ~ 180 [MeV]※exchanging or adding crystals ⇒maximum can be increased
Energy resolution σE(BGO) = 1% for 80 MeVσE(CFT) = 20 % for 1MeV
Angular resolution σθ≃ 1°
Time resolution(CFT) σtime ≃ 1 [ns]
Particle ID : p/d/μ,e,π※depends on particle energy
If you have ideas or interests, please contact us.