Post on 13-Jan-2016
Recent Experiments Involving Few-Nucleon Systems
Werner Tornow
Duke University & Triangle Universities Nuclear Laboratory
Outline• A=3 systems -3He 3-body breakup, n-n QFS in n-2H breakup, -3H three-body breakup
• A=4 systems N-3He Ay() elastic, n-3H () elastic (using Inertial Confinement Fusion (ICF))
• A=5 systems 3H(d,)5He/3H(d,n)4He branching ratio (using ICF)
• A=6 systems 3H(t,2n)4He neutron spectrum (using ICF)
• A=12 system 12C(,3) and the 2+ excitation of the Hoyle 0+ state in 12C
• Outlook and Conclusion
Energy range considered: 50 MeV/N 1
+ 3He -> p + p + n
2
High-Intensity Gamma-ray Source (HIS) @ TUNL
-ray beam parameters Values
Energy 1 – 100 MeV
Linear & circular polarization > 97%
Spatial distribution after collimation (diameter) 10 – 25 mm
Pulse width (FWHM) 0.5 – 0.8 ns
Pulse repetition rate 5.58 MHz
Flux with 2% E/E ( 2 MeV < E < 5 MeV) > 3 × 106 /s
Flux with 5% E/E (5 MeV < E < 20 MeV) > 7 × 107 /s
Flux on with 5% E/E (20 MeV< E < 100
MeV)
> 1 × 107 /s
0.18-0.28 GeV Electron Linac
0.18-1.2 GeV Booster Injector
0.24-1.2 GeV Storage Ring
-ray beam
FEL Undulators
World’s most intense accelerator-driven -ray sourceIntensity 103 /s/eV on target
3
HIS: Intracavity Compton-Back Scattering
Example: Ee = 500 MeV FEL = 400 nm
ħω = 3.11 eV E = 11.9 MeV
Head-on collision: E ≈ 4γ2ħω
2500
1500
500
1950 2000 2050E (keV)
Inte
nsi
ty
E =2032 keV
E =26 keVE/E = 1.3%
Vladimir Litvinenko4
Three-body photodisintegration of 3He with double polarizations at 12.8 and 14.7 MeV at HIGS/TUNL facility (Haiyan Gao’s group)
o Two Primary Goals:o Test state-of-the-art three-body calculations made
by Deltuva [1] and Skibiński [2], and future EFT calculations.
o Important step towards investigating the GDH sum rule for 3He below the pion production threshold :
We detect neutrons!
[1] A. Deltuva et al., Phys. Rev. C 71, 054005 (2005); Phys. Rev. C 72, 054004 (2005) and Nucl. Phys. A 790, 344c (2007).
[2] R. Skibiński et al., Phys. Rev. C 67, 054001 (2003); R. Skibiński et al. Phys. Rev. C 72, 044002 (2005); R.Skibiński. Private communications.
IM
dI N
N
AN
PN
GDH
thr
22
24
Gerasimov-Drell-Hearn
5
Lorentz & gauge invariance, crossing symmetry, causalityand unitarity of the forward Compton scattering amplitude
22
22N
N
AN
PN
thrM
d
)26()027.0(23587.0
232 32 32
3
GeV GeV GeV ppnnHeGDHPGDHPGDH
GeV He
GeV
He
He
He
GDH
GDH
GDH
GDH
thr
thr
32
32
3
3
3
3
b496
M. Amarian, PRL 89, 242301(2002) J.L. Friar et al. PRC 42, 2310 (1990) N. Bianchi, et al. PLB 450, 439 (1999)
Extrapolated from low Q2 3He GDH (E94-010) measurement @ JLab, (E97-110 much lower Q2)
HIγS @ TUNL
b38247
217 39 b ??
b6.99.31
Goal II: GDH Sum Rule on 3He A. Deltuva
6
Apparatus of the Three-body Photodisintegration Experiment
Optics Table
Laser light
1. Automatically movable target and optical table
2. Detectors in mu-metal shielding tubes
D2O cell-flux monitor not shown in the
schematic
Beam enclosed in
vacuum
Beam Direction
7
rays
High-pressure hybrid 3He target polarized longitudinally using spin-exchange optical pumping
cm longPyrex glass tube
atm
8
9
Spin-Dependent Double Differential Cross Sections at 12.8 MeV
Solid curve: R. Skibińskiet al. Dotted curve: A. Deltuva , A. Fonseça 10
Spin-Dependent Single Differential Cross Sections at
12.8 MeV(preliminary)
11
Spin-Dependent Total Cross Sections and the GDH Integrand
Deltuva et al.Skibiński et al.
G. Laskaris et al., Phys. Rev. Lett. 110, 202501 (2013) 12
10 year effort !
Only 3-body part
nn QFS in n + d breakup &
+ 3H three-body breakup
A=3
13
W. von Witsch, A. Siepe et al., 2002
n-p QFS
For n-n QFS theproton detector isreplaced by aneutron detector
2H(d,n)3He
En=26 MeV
14
n + d > n + n + p
W. von Witsch, A. Siepe et al. (Bonn)
np QFS nn-QFSEn=26 MeV
2H(n,np)n 2H(n,nn)p
H. Witała H. Witała
15
X.C. Ruan (CIAE) & W. von Witsch (Bonn), 2007En=25 MeV
nn-QFS2H(n,nn)p
3H(d,n)4He
China Institute of Atomic Energy
H. Witała
16
PulsedDeuteron
Beam
DeuteriumGas Cell
ProtonRecoil
Telescope
Collimator & Shielding Wall
CD2Target
TransmissionFoil Detector
ProtonDetector
NeutronDetector
C6D12Target
NeutronDetector
NeutronBeam
np QFSsetup
nn QFSsetup
1.5 m
NeutronDetector
TUNL np and nn QFS experimental setup
2H(d,n)3He
En=19 MeV
17
18
H. Witała & W. Glöckle
19
Parallel Session B1 (Monday afternoon)
Di-neutron searches
Yushi Maeda 2H(n,p)nn
Kazimierz Bodek -absorption on 3He and 4He
Sergey Zuyev d + T -> 3He + 2n
20
3H(,n)2H3H(,p)nn
R. Skibiński
21
Photon induced three-body breakup of 3H > n +n +p
H. Witała 22
-108 keV-323 keV
23
A=4
N – 3He Analyzing Power Ay() at low energies
24
p – 3He
A. Deltuva
Fisher 2006
McDonald1964
Alley 1993
Entem&MachleidtDoleschall 25
n - 3He
En=1.60 MeV
En=2.26 MeV
En=3.14MeV
En=4.05 MeV
En=5.54 MeV
dashed greenINOY04
dashed blueAV18
solid orangeCD Bonn
dotted redCD Bonn +
J. Esterline et al., PRL 110,152503 ( 2013)
A. Deltuva
26
Nucleon-3He elastic scattering
CD Bonn, 7.26 MeV INOY04, 7.73 MeV
p-3Hep-3He
n-3He
n-3He
27
Four-Nucleon Elastic Scattering
p - 3He T=1
n - 3H T=1
p - 3H T=0,1
n - 3He T=0,1
need data
need better data
28
n -3H elastic () at 14.1 MeV
from
Inertial Confinement Fusion (ICF)
OMEGA @ University of Rochester
29
Plasma serves as both neutron source and targetPlasma serves as both neutron source and target
3.5 m SiO2
20 atmDT gas
30 kJ1-ns square pulseYn = 5×1013
<Ti>n = 9 keV
Elastically-scattered deuterons (d’):
n(14.1MeV) + D n’ + d’ (<12.5 MeV)
Elastically-scattered tritons (t’):
n(14.1MeV) + D n’ + t’ (<10.5 MeV)
Ed’ = (8/9) × En × Cos2nd
Et’ = (3/4) × En × Cos2nt
n'n
d’
DT
SiO2 glass shell burnt away entirely at bang time
n'
t’n
nt
nd
425 m
J. Frenje30
Simultaneous measurements of the d’ and t’ spectra were conducted with a simple magnetic spectrometer (CPS2)
50keV (p)
3 MeV (p)
2cm
OMEGA-target
chamber
30 MeV (p)
15 MeV (d)
10 MeV (t)
CPS2
CR-39:
d’ : 3.7 – 12.5 MeV
t‘ : 2.5 – 10.5 MeV
CR-39:
d’ : 3.7 – 12.5 MeV
t‘ : 2.5 – 10.5 MeV
Target
DD-p spectrum
was also measured
for reference
F.H. Séguin et al., Rev. Sci. Instrum 74, 975 (2003)
60 laser beams
J. Frenje31
d’-signal area
t’-signal area
Bkgd areas
t’-high-energy peak
d’-high-energy peak
Y
X (energy)
d’ and t’ spectra were obtained by selecting signaland background areas and putting constraints on thediameters and darkness of the signal tracks
d’
t’
d’
n,2n-p
J. Frenje32
d’ and t’ spectra were obtained simultaneouslyon three OMEGA shots
The n-t differential cross section was obtained by deconvolving the Doppler broadening and CPS2-response function. The well known n-d differential cross section was used for absolute normalization of the n-t cross section.
The n-t differential cross section was obtained by deconvolving the Doppler broadening and CPS2-response function. The well known n-d differential cross section was used for absolute normalization of the n-t cross section.
J. Frenje33
n-d n-t
Faddeev calculation1
NCSM ab-initio theory3
1 E. Epelbaum et al., PRC 66, 064001 (2002). 2 J.A. Frenje et al., PRL 107, 122502 (2011).3 P. Navrátil et al., LLNL-TR-423504 (2010). 34
3H(d,)5He/3H(d,n)4He
gamma-to-neutron branching ratio
from Inertial Confinement Fusion (ICF)
National Ignition Facility (NIF) Lawrence Livermore National Laboratory
35
National Ignition Facility (NIF) at LLNL
Inertial Confinement Fusion, 192 laser beams, DT capsule in hohlraum
36
Neutron and -ray spectrometry typically used to support the ICF program have been used to explore basic nuclear physics on NIF (and OMEGA)
MRS (77-324)
NITOF (90-315)
Spec-E (90-174)
nTOF4.5m (64-330) nTOF3.9m (64-275)
M. Gatu Johnson et al., RSI (2012).F.E Merrill et al., RSI (2012).Spec-A (116-316)
Cross cut image of the NIF chamber
37
38
Y. Kim et al.Phys. Rev. C 85,061601(R), 2012
Ohio University
39
New acceleratordriven efforts areunderway
T + T neutron spectrum
from
OMEGA and NIF
40
The T+T reaction has been studied extensively at OMEGA and NIF
4 μm SiO210 atm
DT
10 μm CD12 atm
DT
15 μm CH17 atm
DT
20 μm CH17 atm
DT
~230 µm CH
OMEGA
NIF
4 atm at 32 KT2
Possible reactions:
T + T → 4He + 2n (0-9.5 MeV)
T + T → 5He + n (8.7 MeV)
T + T → 5He* + n
Possible reactions:
T + T → 4He + 2n (0-9.5 MeV)
T + T → 5He + n (8.7 MeV)
T + T → 5He* + n
Understanding the T+T reaction at low CM energies has important implications for:
1. Nuclear physics2. Stellar nucleosynthesis [3He(3He,2p)4He]3. HEDP/ICF
Understanding the T+T reaction at low CM energies has important implications for:
1. Nuclear physics2. Stellar nucleosynthesis [3He(3He,2p)4He]3. HEDP/ICF
J. Frenje41
Casey measured the T+T neutron spectrum for the first time using ICF
0
1.0
2.0
3.0
0 5 10 15
Neutron energy [MeV]
dN
/ d
E [
au]
ECM = 23 keV
ECM = 250 keV
ECM = 110 keV
Wong (1965)Allen (1951)Casey (2012)
Casey et al, PRL (2012).Allen et al, PR (1951).Wong et al, NP (1965).
n+5He
n+n+4He
Casey’s measurement was conducted at poor energy resolution, which washes out a possible weak n+5He resonance (<5%). 42
Casey’s measurement was later improved by high-resolution measurements of the T+T neutron spectrum at NIF / OMEGA
R-matrix modeling
G. Hale
43
Nuclear Astrophysics
The 2nd 2+ state in 12C
44
45
Red giant starsResonance enhancement is needed. Nature forms 8Be (ground state is a resonance 92 keVabove the 4He-4He threshold). Helps, but not sufficient. Hoyle (1954) proposed a resonance in 12C just above the combined mass of 8Be and -particle. Observed in 1957.
Nuclear Astrophysics & EFT Lattice Calculations
A 22+ state in 12C was predicted by
Morinaga (Phys. Rev. 101, 1956) as the first rotational state of the “ground” state 7.654 MeV (Hoyle State)
Recently, Epelbaum, Krebs, Lee, Meißner (Phys. Rev. Lett. 106, 192501, 2011) have performed Ab Initio Chiral Effective Field Theory Lattice calculations for the Hoyle State and its structure and rotations.
Epelbaum et al. Phys. Rev. Lett. 109252501 (2012) 46
Hoyle
Optical Time Projection Chamber (OTPC) M. Gai et al.
Gas (Target/Detector) filled volume (CO2+N2) Grid provides the total energy (E/E of 4 %) PMTs provide the Time-Projection (10 ns bins): out-of-plane angle of the track Optical Readout provides the track image: in-plane angle of the track
Evidence of 2nd 2+ state in 12C
+ 12C > 347
48
49
50
Evidence of a New 22+ State in 12C: Results
Experiment:
Comparing the Experimental Results and the lattice EFT Calculation
E(22+ - 02
+) B(E2: E(22+ 01
+)
Experiment 2.37 ± 0.11 0.73 ± 0.13
Theory 2.0 ± 1 to 2 2 ± 1
51
53
54
Nuclear Astrophysics Impact of the 22+ State
o Helium burning occurs at a temperature of 108–109K, and is
completely governed by the Hoyle state;
o However, during type II supernovae, -ray bursts and other
astrophysical phenomena, the temperature rises well above
109 K, and higher energy states in 12C can have a significant
effect on the triple- reaction rate;
o Preliminary calculations suggest a dependence of high mass
number (>140) abundances on the triple alpha reaction rate
based on the parameters of the 22+ state.
55
Outlook
What’s next at TUNL ?
56
Few-Body Physics Studies at HIGS
o HIGS is currently mounting the GDH experiment on the deuteron
o Installation of the HIGS Frozen Spin Target (HIFROST) is ongoing
o The majority of data taking will be completed by the end of 2013 between 4 and 16 MeV
Phys. Rev. C78, 034003 (2008)Phys. Rev. C77, 044005 (2008)
57
IM
dI N
N
AN
PN
GDH
thr
22
24
Gerasimov-Drell-Hearn Sum Rule on the Deuteron
Ip=204.8 b In=232.5 b Id=0.652 b
Above pion production threshold: Large positive value
Below pion production threshold: Large negative value
58
Setup for GDH Measurement on Deuteron
Frozen-spin polarized targetHIFROST
59
Compton Scattering
The T-matrix for the Compton scattering of incoming photon of energy with a spin () ½ target is described by six structure functions
= photon polarization, k is the momentum
60
HIGS Results on 16O and 6Li Compton Scattering
16O
6Lio Giant Resonanceso Quasi-Deuterono Modified Thompson
Phenomenological Model
61
BPT with Prediction = 10.7 ± 0.7 = 4.0 ± 0.7
PDG Accepted Value = 12.7 ± 0.6 = 1.9 ± 0.5
62
What’s next elsewhere at low energies?
ICF facilities may play a major role in experimental Few-Body Physics
63
HIS2 Layout
Mirrors of FP optical cavityLcav = 1.679 mPFB (avg) > 10 kW, 90 MHz
Collaborators: Jun Ye, JILA and U. of Colorado at Boulder
-ray
e-beam Laser beam
64
What’s new beyond the next 5 years: HIS2
Comparison of HIS2 to ELI
ELI: Extreme Light Infrastructure Bucharest, Prague, Szeged
65
Backup Slides
CD Bonn INOY04A=4 Nucleon-3Heelastic scattering p-3He p-3He
n-3Hen-3He
p-3H
p-3H
68from W. Tornow et al., Phys. Lett. B 702, 121 (2011)
References: Raut et al., PRL, 108, 042502 (2012), and Tornow et al., PR C85, 061001R (2012)
The Few-Body System: 4He Inconsistencies !
World Data on4He(,n)3He 4He(,p)3H
The Few-Body System: 4He Results from HIGS
The Few-Body System: 4He Results from HIGS