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