Darmstadt 2016 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 19: Nuclear Astrophysics III
HK 19.4: Talk
Tuesday, March 15, 2016, 15:00–15:15, S1/01 A02
Quartic isospin-asymmetry energy of nuclear matter from chiral pion-nucleon dynamics — •Norbert Kaiser — Physik Department T39, Technische Universität München
Based on a chiral approach to nuclear matter, the quartic term in the expansion
of the equation of state of isospin-asymmetric nuclear matter is calculated [Phys. Rev. C 91, 065201 (2015)]. The contributions to the quartic isospin asymmetry energy A4(kf) arising from 1π-exchange and chiral 2π-exchange in nuclear matter are calculated analytically together with three-body terms involving virtual
Δ(1232)-isobars. From these interaction terms one obtains at saturation density ρ0 = 0.16 fm−3 the value A4(kf0)= 1.5 MeV, more than three times as large as the kinetic energy part. Moreover, iterated 1π-exchange exhibits components for which the fourth derivative with the respect to the isospin-asymmetry parameter δ becomes
singular at δ =0. The genuine presence of a non-analytical term δ4 ln|δ| in the expansion of the energy per particle of isospin-asymmetric nuclear matter is demonstrated by evaluating a s-wave contact interaction at second order.
Work supported in part by DFG and NSFC (CRC110).