Recent Experiments Involving Few-Nucleon Systems Werner Tornow Duke University & Triangle Universities Nuclear Laboratory

Outline A=3 systems  - 3 He 3-body breakup, n-n QFS in n- 2 H breakup,  - 3 H three-body breakup A=4 systems N- 3 He A y (  ) elastic, n- 3 H  (  ) elastic (using Inertial Confinement Fusion (ICF)) A=5 systems 3 H(d,  ) 5 He/ 3 H(d,n) 4 He branching ratio (using ICF) A=6 systems 3 H(t,2n) 4 He neutron spectrum (using ICF) A=12 system 12 C( ,3  ) and the 2 + excitation of the Hoyle 0 + state in 12 C Outlook and Conclusion Energy range considered: 50 MeV/N 1

  + 3 He -> p + p + n 2

High-Intensity Gamma-ray Source (HI  TUNL  -ray beam parameters Values Energy1 – 100 MeV Linear & circular polarization> 97% Spatial distribution after collimation (diameter)10 – 25 mm Pulse width (FWHM)0.5 – 0.8 ns Pulse repetition rate5.58 MHz Flux with 2%  E  /E  ( 2 MeV < E  < 5 MeV)> 3 × 10 6  /s Flux with 5%  E  /E  (5 MeV < E  < 20 MeV)> 7 × 10 7  /s Flux on with 5%  E  /E  (20 MeV< E  < 100 MeV) > 1 × 10 7  /s GeV Electron Linac GeV Booster Injector GeV Storage Ring  -ray beam FEL Undulators World’s most intense accelerator-driven  -ray source Intensity 10 3  /s/eV on target 3

HI  S: Intracavity Compton-Back Scattering Example: E e = 500 MeV    FEL = 400 nm ħω = 3.11 eV E  = 11.9 MeV Head-on collision: E  ≈ 4 γ 2 ħω E  (keV) Intensity E  =2032 keV  E  =26 keV  E/E = 1.3% Vladimir Litvinenko 4

Three-body photodisintegration of 3 He 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 3 He below the pion production threshold : We detect neutrons! [1] A. Deltuva et al., Phys. Rev. C 71, (2005); Phys. Rev. C 72, (2005) and Nucl. Phys. A 790, 344c (2007). [2] R. Skibiński et al., Phys. Rev. C 67, (2003); R. Skibiński et al. Phys. Rev. C 72, (2005); R.Skibiński. Private communications. Gerasimov-Drell-Hearn 5 Lorentz & gauge invariance, crossing symmetry, causality and unitarity of the forward Compton scattering amplitude

M. Amarian, PRL 89, (2002) J.L. Friar et al. PRC 42, 2310 (1990) N. Bianchi, et al. PLB 450, 439 (1999) Extrapolated from low Q 2 3 He GDH (E94-010) JLab, (E much lower Q 2 ) TUNL ?? Goal II: GDH Sum Rule on 3 He 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 3 He target polarized longitudinally using spin-exchange optical pumping  cm long Pyrex glass tube  atm 8

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Spin-Dependent Double Differential Cross Sections at 12.8 MeV Solid curve: R. Skibiński  et 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 This work 12.8 Deltuva et al This work 14.7 Deltuva et al Deltuva et al. Skibiński et al. G. Laskaris et al., Phys. Rev. Lett. 110, (2013) year effort ! Only 3-body part

nn QFS in n + d breakup &  + 3 H three-body breakup A=3 13

W. von Witsch, A. Siepe et al., 2002 n-p QFS For n-n QFS the proton detector is replaced by a neutron detector 2 H(d,n) 3 He E n =26 MeV 14 n + d > n + n + p

W. von Witsch, A. Siepe et al. (Bonn) np QFS nn-QFS E n =26 MeV 2 H(n,np)n 2 H(n,nn)p H. Witała 15

X.C. Ruan (CIAE) & W. von Witsch (Bonn), 2007 E n =25 MeV nn-QFS 2 H(n,nn)p 3 H(d,n) 4 He China Institute of Atomic Energy H. Witała 16

TUNL np and nn QFS experimental setup 2 H(d,n) 3 He E n =19 MeV 17

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H. Witała & W. Glöckle 19

Parallel Session B1 (Monday afternoon) Di-neutron searches Yushi Maeda 2 H(n,p)nn Kazimierz Bodek  -absorption on 3 He and 4 He Sergey Zuyev d + T -> 3 He + 2 n 20

3 H( ,n) 2 H 3 H( ,p)nn R. Skibiński 21

Photon induced three-body breakup of 3 H > n +n +p H. Witała keV -323 keV

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A=4 N – 3 He Analyzing Power A y (  ) at low energies 24

p – 3 He A. Deltuva Fisher 2006 McDonald 1964 Alley 1993 Entem&Machleidt Doleschall 25

n - 3 He E n =1.60 MeV E n =2.26 MeV E n =3.14MeV E n =4.05 MeV E n =5.54 MeV dashed green INOY04 dashed blue AV18 solid orange CD Bonn dotted red CD Bonn +  J. Esterline et al., PRL 110, ( 2013) A. Deltuva 26

Nucleon- 3 He elastic scattering CD Bonn, 7.26 MeV INOY04, 7.73 MeV p- 3 He n- 3 He 27

Four-Nucleon Elastic Scattering p - 3 He T=1 n - 3 H T=1 p - 3 H T=0,1 n - 3 He T=0,1 need data need better data 28

 n - 3 H elastic  (  ) at 14.1 MeV from Inertial Confinement Fusion (ICF) University of Rochester 29

Plasma serves as both neutron source and target 3.5  m SiO 2 20 atm DT gas 30 kJ 1-ns square pulse Y n = 5×10 13 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) E d’ = (8/9) × E n × Cos 2  nd E t’ = (3/4) × E n × Cos 2  nt n' n d’ DT SiO 2 glass shell burnt away entirely at bang time n' t’ n  nt  nd 425  m J. Frenje 30

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 signal and background areas and putting constraints on the diameters and darkness of the signal tracks d’d’ t’ d’ n,2n-p J. Frenje 32

d’ and t’ spectra were obtained simultaneously on 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. J. Frenje 33

n-dn-t Faddeev calculation 1 NCSM ab-initio theory 3 1 E. Epelbaum et al., PRC 66, (2002). 2 J.A. Frenje et al., PRL 107, (2011). 3 P. Navrátil et al., LLNL-TR (2010). 34

 3 H(d,  ) 5 He/ 3 H(d,n) 4 He  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 ( ) Cross cut image of the NIF chamber 37

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Y. Kim et al. Phys. Rev. C 85, (R), 2012 Ohio University 39 New accelerator driven efforts are underway

 T + T neutron spectrum from OMEGA and NIF 40

The T+T reaction has been studied extensively at OMEGA and NIF 4 μm SiO 2 10 atm DT 10 μm CD 12 atm DT 15 μm CH 17 atm DT 20 μm CH 17 atm DT ~230 µm CH OMEGA NIF 4 atm at 32 K T 2 Possible reactions: T + T→ 4 He + 2n (0-9.5 MeV) T + T→ 5 He + n (8.7 MeV) T + T→ 5 He* + n Possible reactions: T + T→ 4 He + 2n (0-9.5 MeV) T + T→ 5 He + n (8.7 MeV) T + T→ 5 He* + n Understanding the T+T reaction at low CM energies has important implications for: 1.Nuclear physics 2.Stellar nucleosynthesis [ 3 He( 3 He,2p) 4 He] 3.HEDP/ICF Understanding the T+T reaction at low CM energies has important implications for: 1.Nuclear physics 2.Stellar nucleosynthesis [ 3 He( 3 He,2p) 4 He] 3.HEDP/ICF J. Frenje 41

Casey measured the T+T neutron spectrum for the first time using ICF E CM = 23 keV E CM = 250 keV E CM = 110 keV Wong (1965) Allen (1951) Casey (2012) Casey et al, PRL (2012). Allen et al, PR (1951). Wong et al, NP (1965). n+ 5 He n+n+ 4 He 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 2 nd 2 + state in 12 C 44

45 Red giant stars Resonance enhancement is needed. Nature forms 8 Be (ground state is a resonance 92 keV above the 4 He- 4 He threshold). Helps, but not sufficient. Hoyle (1954) proposed a resonance in 12 C just above the combined mass of 8 Be and  -particle. Observed in 1957.

Nuclear Astrophysics & EFT Lattice Calculations A state in 12 C was predicted by Morinaga (Phys. Rev. 101, 1956) as the first rotational state of the “ground” state MeV (Hoyle State) Recently, Epelbaum, Krebs, Lee, Meißner (Phys. Rev. Lett. 106, , 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 (2012) 46 Hoyle

Optical Time Projection Chamber (OTPC) M. Gai et al.  Gas (Target/Detector) filled volume (CO 2 +N 2 )  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 2 nd 2 + state in 12 C  + 12 C > 3  47

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Evidence of a New State in 12 C: Results Experiment: Comparing the Experimental Results and the lattice EFT Calculation E( )B(E2: E(2 2 +  ) Experiment2.37 ± ± 0.13 Theory2.0 ± 1 to 22 ± 1 51

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Nuclear Astrophysics Impact of the State o Helium burning occurs at a temperature of 10 8 –10 9 K, 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 10 9 K, and higher energy states in 12 C 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 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, (2008) Phys. Rev. C77, (2008) 57

Gerasimov-Drell-Hearn Sum Rule on the Deuteron I p =204.8  b I n =232.5  b I d =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 target HIFROST 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 16 O and 6 Li Compton Scattering 16 O 6 Li o Giant Resonances o Quasi-Deuteron o Modified Thompson Phenomenological Model 61

B  PT with  Prediction  = 10.7 ± 0.7  = 4.0 ± 0.7 PDG Accepted Value  = 12.7 ± 0.6  = 1.9 ±

What’s next elsewhere at low energies? ICF facilities may play a major role in experimental Few-Body Physics 63

HI  S2 Layout Mirrors of FP optical cavity L cav = m P FB (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: HI  S2 Comparison of HI  S2 to ELI ELI: Extreme Light Infrastructure Bucharest, Prague, Szeged 65

Backup Slides

CD BonnINOY04 A=4 Nucleon- 3 He elastic scattering p- 3 He n- 3 He p- 3 H

68 from W. Tornow et al., Phys. Lett. B 702, 121 (2011)

References: Raut et al., PRL, 108, (2012), and Tornow et al., PR C85, R (2012) The Few-Body System: 4 He Inconsistencies ! World Data on 4 He( ,n) 3 He 4 He( ,p) 3 H

The Few-Body System: 4 He Results from HIGS