hg: Chiral Structure of Few-Nucleon Systems

Transcription

1 Chiral Structure of Few-Nucleon Systems H. W. Grießhammer Center for Nuclear Studies, The George Washington University, Washington DC, USA D. R. Phillips: Chiral Dynamics with πs, Ns and s Done. hg: Chiral Structure of Few-Nucleon Systems Now. H. Weller: Probing Chiral Dynamics with Photons Next. Unified description of Nuclear Physics, rooted in QCD. Unique signatures of Chiral Physics & few-n forces. Reliable high-accuracy predictions and extractions of nucleonic and nuclear properties. My apologies for omissons, mis-representations and mistakes. Opportunities FewN, LRP-Rutgers 27 2, Grießhammer, CNS@GWU 1-1

2 Weinberg, Ordóñez/Ray/van Kolck, Friar/Coon, Kaiser/Brockmann/Weise, Epelbaum/Glöckle/Meißner, Entem/Machleidt, Kaiser, Higa/Robilotta, Epelbaum,... (a) Few-Nucleon Interactions in χ EFT typ. momentum breakdown scale 1 Long-Range: correct symmetries and IR degrees of freedom: Chiral Dynamics Short-Range: symmetries constrain contact-ints to simplify UV: Minimal parameter-set Hierarchy: 2NF-effects 3NF-effects 4NF-effects π LO NLO N2 LO N3 LO 2N ints etc. p2 2 parameter +7 parameter p4 + parameter D 3N ints 2 parameter +15 = 24 param. E etc. parameter-free, in progress 4N ints etc. parameter-free Opportunities FewN, LRP-Rutgers 27 2, Grießhammer, CNS@GWU 2-1

3 (b) Two Nucleons in χeft Entem/Machleidt 23, Epelbaum/Glöckle/Meißner 25 Neutron-proton phase shifts up to N 3 LO np scattering at 5 MeV d /d [mb/sr] NLO N 2 LO N 3 LO A y N 2 LO N 3 LO PWA Bands estimate higher-order effects. LO NLO N 2 LO N 3 LO AV 18 # of parameters = 24 4 χ 2 /d.o.f in np Future: High-accuracy deuteron physics, Dynamical (1232), P, weak, iso-spin breaking, T = 3 2 3NFs,... Opportunities FewN, LRP-Rutgers 27 2, Grießhammer, CNS@GWU 3-1

4 (c) Test: Deuteron Form-Factors Phillips 23-6 Charge Form-Factor Measure for Quadrupole Form-Factor: t 2R t 2 Q 2 BLAST, normalised at Q = {1.88;2.5} fm G C -2 NNLO NLO OPEP + R=1.5 fm CD-Bonn Nijm q (MeV) Bands estimate higher-order effects. BLAST PRELIMINARY χeft: one C.T. at N 3 LO S D by quadrupole moment Future: Experiment: JLab to resolve A(Q 2 )-discrepancy Saclay vs. MAMI Normalisation of t 2 Theory: Breakup (e,e N), more nuclei Higher orders Opportunities FewN, LRP-Rutgers 27 2, Grießhammer, CNS@GWU 4-1

5 (d) Nuclei as Neutron Targets: Compton Scattering Beane/Malheiro/McGovern/Phillips/van Kolck 21-4, hg/hemmert/hildebrandt/phillips N-structure: α s E1,β s M1 2N-structure: S NN etc. All data below MeV: Illinois, Lund, Saskatoon Nπ only Nπ + + stat. error Nucleon [ 4 fm 3 ]: ᾱ s = 11.3 ±.7 stat ±.6 Σ ± 1 theory β s = stat ±.6 Σ ± 1 theory Proton hg/... 23: ᾱ p = 11. ± 1.4 stat ±.4 Σ ± 1 theory β p = stat ±.4 Σ ± 1 theory previous ranges nucleon: ᾱ s =[6...18] β s =[ 4...9] = neutron proton polarisabilities, important. as predicted by χeft. Opportunities FewN, LRP-Rutgers 27 2, Grießhammer, CNS@GWU 5-1

6 (e) Future of Compton Scattering Compton on 3 He Spin-Pols from 3 He d Compton at MAXlab 9 Choudhury/Phillips/Nogga 26 6 MeV 75 8 MeV β n =-2x -4 fm 3 β n =-2x -4 fm 3 Choudhury/Phillips/Nogga 26 γ 1n (x -4 fm 4 ) varying γ 2n (x -4 fm 4 ) varying ongoing dσ/dω (nb/sr) β n = β n = 2x -4 fm 3 β n = 4x -4 fm 3 β n = 6x -4 fm β n = β n = 2x -4 fm 3 βn= 4x -4 fm 3 β n = 6x -4 fm MeV 12 MeV 5 25 β n =-2x -4 fm 3 β n =-2x -4 fm 3 z (nb/sr) - γ 1n =-4.4 γ 1n =-2.2 γ 1n = γ 1n = 2.2 γ 1n = γ 2n =-2.2 γ 2n =-1.1 γ 2n = γ 2n = 1.1 γ 2n = γ 3n (x -4 fm 4 ) varying γ 4n (x -4 fm 4 ) varying dσ/dω (nb/sr) β n = β n = 2x -4 fm 3 β n = 4x -4 fm 3 β n = 6x -4 fm c.m. angle (deg) 2 15 β n = β n = 2x -4 fm 3 β n = 4x -4 fm 3 β n = 6x -4 fm c.m. angle (deg) z (nb/sr) - γ 3n =-1.1 γ 3n =-.55 γ 3n = γ 3n =.55 γ 3n = c.m. angle (deg) - γ 4n =-1.1 γ 4n =-.55 γ 4n = γ 4n =.55 γ 4n = c.m. angle (deg) Theory: Inelastic, N 2 LO, resonance region: -resummation; ω- and Q 2 -dependence;... Short-distance origin of C.T.s δᾱ, δ β. Experiment: Call for data answered by MAXlab, HIγS,... : precision experiments on p, d, 3 H, 3 He polarised S S S S S S S S S S S S σ n p pion cloud difference, response of nucleon-spin constituents: spin-pols π+ π+ π+ π+ N N N N N N N N N N N N Opportunities FewN, LRP-Rutgers 27 2, Grießhammer, CNS@GWU 6-1

7 (f) Data and Few-Nucleon χeft: Examples for N > 2 Polarisation transfer coeffs., E p = 22.7 MeV Light Nuclei d( p, p)d d( p, d)p E x [MeV] w/o 3NF w/ 3NF-A NCSM - 6 Li T= Idaho N3LO w/ 3NF-B Expt E x [MeV] w/o 3NF w/ 3NF-A NCSM - 7 Li T=1/2 Idaho N3LO w/ 3NF-B Expt. 5/2-5/2-7/2-1/2-3/2 - NCSM Nogga/Navrátil/Barrett/Vary 26 Coverage Problem Example Epelbaum/Glöckle/Gołak/Meißner/Witała, data: Krakow 26 Bands estimate higher-order effects. The more nucleons, the less data. = More experiments also at low energies! Tandem@TUNL,... Opportunities FewN, LRP-Rutgers 27 2, Grießhammer, CNS@GWU 7-1

8 (g) Few-Nucleon χeft: A Merger of Opportunities A 4: Merge χeft with well-developed but sophisticated numerical techniques. Several new collaborations explore this, for example: 4 σ γ [mb] 3 2 Total Photo-Absorption on 4 He NCSM Navrátil, Nogga, Stetcu, Barrett, Vary, van Kolck,... Spectra, radii, halo-nuclei,... EIHH-Lorentz-Integral-Transform Leidemann/Orlandini/hg/... Preferred inclusive reactions A 8 Resonating Group Model Hofmann/hg/... Preferred exclusive reactions A 16 1 AV18 AV18+UIX (bounds) EIHH-LIT ω [MeV] HIγS, MAXlab proposals Tandem@TUNL 26 χeft on the Lattice D. Lee/Th. Schäfer/Borasoy/Epelbaum/Krebs/Meißner Simulate χeft of nuclei and nuclear matter A y MeV (exp) - A y (th)]/ A y [ A (exp) y n+d p+ 3 He p+d A y : theory vs. exp Laboratory Energy [MeV] Opportunities FewN, LRP-Rutgers 27 2, Grießhammer, CNS@GWU 8-1

9 (h) Error-Bars for Nuclear Physics χeft as low-energy QCD Unified, systematic description, rooted in QCD. Derive from QCD via lattice. Mean Field Models Ò ØÝ ÙÒØ ÓÒ Ð Proton Number Bridge to Nuclear Structure. 1 QCD QCD Vacuum QCD Vacuum Microscopic Ab Initio χ Ì Ì /πµ 3 À 4 À Ô 3À Ò Shell Model(s) Quark-Gluon Interaction Effective Interactions chart adapted from G. Henning Neutron Number Opportunities FewN, LRP-Rutgers 27 2, Grießhammer, CNS@GWU 9-1

10 (h) Error-Bars for Nuclear Physics Proton Number χeft as low-energy QCD Unified, systematic description, rooted in QCD. Derive from QCD via lattice. Bridge to Nuclear Structure. 1 QCD QCD Vacuum QCD Vacuum Microscopic Ab Initio χ Ì Ì /πµ 3 À 4 À Ô 3À Ò Shell Model(s) Quark-Gluon Interaction Quantitative studies of few-n systems Mean Field Models High-accuracy neutron properties from light nuclei: Ò ØÝ polarisabilities, ÙÒØ ÓÒ Ða nn, π-prod., iso-spin violation, a πn from pionic atoms,... Unique signals of chirality, 3NF, 4NF,... QCD Effective Interactions Frontiers: Halo-nuclei, Hyper-nuclei,... χeft vs. EFT(/π): Chiral Dynamics or Universality? chart adapted from G. Henning Neutron Number Opportunities FewN, LRP-Rutgers 27 2, Grießhammer, CNS@GWU 9-2

11 (h) Error-Bars for Nuclear Physics Proton Number χeft as low-energy QCD Unified, systematic description, rooted in QCD. Derive from QCD via lattice. Bridge to Nuclear Structure. 1 QCD QCD Vacuum QCD Vacuum Microscopic Ab Initio χ Ì Ì /πµ 3 À 4 À Ô 3À Ò Shell Model(s) Quark-Gluon Interaction Quantitative studies of few-n systems Mean Field Models High-accuracy neutron properties from light nuclei: Ò ØÝ polarisabilities, ÙÒØ ÓÒ Ða nn, π-prod., iso-spin violation, a πn from pionic atoms,... Unique signals of chirality, 3NF, 4NF,... QCD Effective Interactions Frontiers: Halo-nuclei, Hyper-nuclei,... χeft vs. EFT(/π): Chiral Dynamics or Universality? Reliable predictions for processes hard-to-access: Astrophysics: Uncertainties Big-Bang Nucleosynthesis: d(p,γ) 3 He, 3 He(d,p) 4 He, 3 He( 4 He,γ) 7 Be,... Protostar-collapse, supernovae, neutron stars,... Neutrinos: hep-process 3 He+p 4 He+e + + ν e Factor 4 SSM(pot.) SuperK with strong ν-mixing Physics beyond the Standard Model? chart adapted from G. Henning Neutron Number Alternative Worlds: spectra, rates, BBN,... sensitive to QCD-parameters m q, α s, N c,... Opportunities FewN, LRP-Rutgers 27 2, Grießhammer, CNS@GWU 9-3

12 (i) χeft, Few-N Interactions and QCD Lattice Simulations χeft: long-range correlations well understood, short-distance QCD encoded in minimal parameter-set. = χeft for extrapolation in m q m 2 π,..., volume, lattice-spacing. m π -dependence of NN-scatt. lengths from MILC-lattices (unquenched) NPLQCD 26 Future: Fully dynamical simulations utilising χeft for long-range part. Verify NN-potential from first principles cf. Ishii/Aoki/Hatsuda 26 (quenched) Fix parameters hard to determine experimentally: weak int. s, πnn- & YN-couplings... cf. Chicago meeting Explain fine-tuning of NN-scattering lengths, origin of few-n int. s Implications of QCD-parameter changes on Nuclear Physics, BBN etc. e.g. Kneller/McLaughlin 23 Opportunities FewN, LRP-Rutgers 27 2, Grießhammer, CNS@GWU -1

13 (j) χeft at Very Low Energies: EFT(/π) Bethe,... Very low momenta m π = only contact ints between nucleons: systematised Eff. Range Expansion etc. = etc. EFT(/π): Universal aspects of systems with large scattering lengths. 3 H 4 He binding energy correlation B α [MeV] B t [MeV] Platter/Hammer/Meißner 24 nd tγ at thermal energies pot. models (different short-dist.) [ ] mb Kievsky/Schiavilla/Viviani + Marucci/Rosati experiment Jurney 1982 N 2 LO EFT(/π) Sadeghi/Bayegan/hg 26 [.58 ±.15] mb [.53 ±.3] mb EFT(/π) input: scatt. lengthes, eff. ranges of 2N, 3N S-waves, thermal np dγ. No new parameter, no new 3NF. Differentiate between Universality and signals of Chiral Symmetry! Opportunities FewN, LRP-Rutgers 27 2, Grießhammer, CNS@GWU 11-1

14 (k) Hypernuclei: Third Axis of the Nuclear Chart Strangeness & Baryon Octet: Chiral Dynamics of SU f (3)-Breaking Only 35 YN data (often pre-1971) + Hypernuclei YNN, YYN enhanced over 3NF? = Composition of neutron star, K-condensation,... HYP6 conference poster Opportunities FewN, LRP-Rutgers 27 2, Grießhammer, CNS@GWU 12-1

15 (k) Hypernuclei: Third Axis of the Nuclear Chart Λ,Σ Λ,Σ LO χeft for YN: π,k,η Polinder/Haidenbauer/Meißner 26 N N 5 parameter Phase-Shifts from lattice using EFT NPLQCD 26 δ( k = 255 MeV ) (degrees) nλ ( 1 S ) EFT 6 Juelich 4 Nijmegen NSC97f NPLQCD m π (MeV) nλ ( 3 S 1 ) 4 δ( k = 168 MeV ) (degrees) EFT 6 Juelich 4 Nijmegen NSC97f NPLQCD m π (MeV) B( 3 Λ B( 3 Λ H) = 2.35 ±.1 MeV χeft H) = 2.35 ±.5 MeV exp Determine unknowns from lattice, feed into χeft, predict. Opportunities FewN, LRP-Rutgers 27 2, Grießhammer, CNS@GWU 12-2

16 (l) Conclusions Proton Number χeft as low-energy QCD Unified, systematic description, rooted in QCD. Derive from QCD via lattice. Bridge to Nuclear Structure. 1 QCD QCD Vacuum QCD Vacuum Microscopic Ab Initio χ Ì Ì /πµ 3 À 4 À Ô 3À Ò Shell Model(s) Quark-Gluon Interaction Quantitative studies of few-n systems Mean Field Models High-accuracy neutron properties from light nuclei: Ò ØÝ polarisabilities, ÙÒØ ÓÒ Ða nn, π-prod., iso-spin violation, a πn from pionic atoms,... Unique signals of chirality, 3NF, 4NF,... QCD Effective Interactions Frontiers: Halo-nuclei, Hyper-nuclei,... χeft vs. EFT(/π): Chiral Dynamics or Universality? Reliable predictions for processes hard-to-access: Astrophysics: Uncertainties Big-Bang Nucleosynthesis: d(p,γ) 3 He, 3 He(d,p) 4 He, 3 He( 4 He,γ) 7 Be,... Protostar-collapse, supernovae, neutron stars,... Neutrinos: hep-process 3 He+p 4 He+e + + ν e Factor 4 SSM(pot.) SuperK with strong ν-mixing Physics beyond the Standard Model? chart adapted from G. Henning Neutron Number Alternative Worlds: spectra, rates, BBN,... sensitive to QCD-parameters m q, α s, N c,... Opportunities FewN, LRP-Rutgers 27 2, Grießhammer, CNS@GWU 13-3