2016 Nuclear Physics School June 20 24 2016

2016 Nuclear Physics School June 20 – 24, 2016 APCTP Headquarters, Pohang Nuclear Forces - Lecture 7 Recent Developments R. Machleidt University of Idaho Nuclear Lecture 76 Nuclear Forces -- Lecture NF from EFT(Pohang II (Pohang 2016) Recent 2016) 1

Nuclear Forces - Overview of all lectures • Lecture 1: Historical perspective • Lecture 2: Properties and phenomenology of the nuclear force • Lecture 3: The meson theory of nuclear forces • Lecture 4: QCD and nuclear forces; the symmetries of lowenergy QCD • Lecture 5: Effective field theory (EFT) for low-energy QCD and nuclear two-body forces • Lecture 6: Nuclear many-body forces from chiral EFT • Lecture 7: Recent Developments R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 2

Outline • “New” ideas and revisions of chiral forces up • • to N 3 LO The need to go beyond N 3 LO Two- and three-nucleon forces at N 4 LO The NN interaction at N 5 LO Outlook R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 3

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Status A. D. 2000 R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 5

But: Recent revival: Ekstroem et al. , 2013+ NNLOopt NNLOsat NNLOsep NNLOsim R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 6

Status A. D. 2003 R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 7

But also here: Recent revival: Epelbaum et al. , 2015 “New Generation of Potentials” R. Machleidt Nuclear Chiral. Forces nuclear- Lecture forces 7 PKU-CUSTIPEN, Recent (Pohang August 2016) 2, 2015 8

Why revival at N 3 LO? Problems with the old Bochum potentials: Bad fit, bad chi 2 R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 9

Problems with the new Bochum potentials • Fitted to phase shifts. As pointed out correctly by the Nijmegen group some 20 years ago, phase shift chi 2 can be very misleading concerning the true reproduction of the NN data. • Comparison is made to just one data set: Abfalterer et al. 2001, 78 np total cross section data. Even the craziest NN potential can fit one data set. The point is to fit all 4000+ NN data. R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 10

Problems with the new Bochum potentials, continued • The potentials use local cutoffs: But potentials with local cutoffs stay non-zero up to several Ge. V, far beyond the validity of chiral EFT. R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 11

d n. a ” ” on. But also here: w e ati n r “ Recent revival: e o n s e Epelbaum et al. , 2014 t G o N a“ “New Generation of t Potentials” No R. Machleidt Nuclear Chiral. Forces nuclear- Lecture forces 7 PKU-CUSTIPEN, Recent (Pohang August 2016) 2, 2015 12

Status A. D. 2010 R. Machleidt Nuclear Chiral. Forces nuclear- Lecture forces 7 PKU-CUSTIPEN, Recent (Pohang August 2016) 2, 2015 13

Evaluate the current status of results From applications of chiral forces. • 2 NFs and 3 NFs up to N 3 LO have been applied in • • nuclear few- and many-body systems. In general, quite a bit of success, but some persistent problems remain. In the few-body sector: Ay puzzle, N-d break-up, … R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 14

Evaluate current status. Anything left to do in the nuclear force business? • Current status: 2 NFs and 3 NFs up to N 3 LO are • • • applied in nuclear few- and many-body systems. In general, quite a bit of success, but some persistent problems remain. In the few-body sector: Ay puzzle, N-d break-up, … Light nuclei: Spectra not perfect. R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 15

Evaluate current status. Anything left to do in the nuclear force business? • Current status: 2 NFs and 3 NFs up to N 3 LO are • • applied in nuclear few- and many-body systems. In general, quite a bit of success, but some persistent problems remain. In the few-body sector: Ay puzzle, N-d break-up, … Light nuclei: Spectra not perfect. Intermediate nuclei: Overbinding. R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 16

Ground-state energies from O-16 to Sn-132 obtained in CC with 2 NF + 3 NF From S. Binder et al. , PLB 736, 119 (2014). R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 17

Evaluate current status. Anything left to do in the nuclear force business? • Current status: 2 NFs and 3 NFs up to N 3 LO are applied • • • in nuclear few- and many-body systems. In general, quite a bit of success, but some persistent problems remain. In the few-body sector: Ay puzzle, N-d break-up, … Light nuclei: Spectra not perfect. Intermediate nuclei: Overbinding. Convergence of the chiral expansion in the many-body system? Not converged at N 3 LO (F. Sammarruca et al. , PRC 91, 054311 (2015)). R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 18

N 3 LO N 2 LO NLO R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 19

Because of the problems just pointed out, improvement of current nuclear forces is called for. • How? • Go to next order! • That is: Turn to N 4 LO. • What can we expect from N 4 LO? • Does N 4 LO have anything to offer we were not offered before? R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 20

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1 -loop graphs: 5 topologies 2 PE R. Machleidt 2 PE-1 PE Ring Krebs et al. (2012, 2013) Contact-1 PE Nuclear Forces - Lecture 7 Recent (Pohang 2016) Contact-2 PE 24

1 -loop graphs: 5 topologies 2 PE R. Machleidt 2 PE-1 PE Ring Krebs et al. (2012, 2013) Contact-1 PE Nuclear Forces - Lecture 7 Recent (Pohang 2016) Contact-2 PE 25

1 -loop graphs: 5 topologies 2 PE-1 PE Ring Krebs et al. (2012, 2013) Contact-1 PE Contact-2 PE 3 NF contacts at N 4 LO Girlanda, Kievsky, Viviani, PRC 84, 014001 (2011) R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 26

All possible 20 isospin-momentum/position structures occur in the 3 NF at N 3 LO! Epelbaum et al. , Eur. Phys. J. A 51, 26 (2015) R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 27

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Because of the problems demonstrated, improvement of current nuclear forces indicated • How? • Go to next order! • That is: Turn to N 4 LO. • What can we expect from N 4 LO? • Does N 4 LO have anything to offer we were not offered before? Oh yes! All 3 NFs you have ever dreamed of! R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 29

What else is there at N 4 LO? R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 30

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N 4 LO effects on NN scattering in peripheral partial waves From Entem, Kaiser, Machleidt, Nosyk, PRC 91, 014002 (2015) R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 33

Using LECs from pi-N Analysis at order four. R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) From Entem, Kaiser, Machleidt, Nosyk, PRC 91, 014002 (2015) 34

How about convergence? R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 35

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Convergence at N 5 LO R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 40

At N 5 LO: Super-accurate Potential possible R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 41

Map of Chartere d and Uncharte red Waters R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 42

Conclusions • The chiral force market has become divers: • • • “new” forces at NNLO and N 3 LO; Be critical! N 3 LO won’t solve all our problems. Turn to N 4 LO: Complete set of 3 NFs and new 3 NF contacts. 2 NF at N 4 LO very quantitative including the peripheral waves (N 4 LO NN pots becoming available). Convergence of NN occurs at N 5 LO. There are now enough forces on the market to keep you either busy or confused. R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 43

The End R. Machleidt Nuclear Forces - Lecture 7 Recent (Pohang 2016) 44