Séminaire "Scattering of few nucleons in NLO Pionless Effective Field Theory - n-d, n-3H, n-3He, and n-4He elastic scattering" M. Schafer (Prague)

jeudi 8 déc. 2022, 11:30 → 12:50 Europe/Paris

Amphi Grunewald (Bat 25)

Pionless effective field theory (EFT) represents a highly convenient tool which allows us to describe nucleon interactions at low energies using a minimal set of input parameters.  Pionless EFT at leading order has been used to study various systems up to 16O, however, only with little success, rendering A > 4 nuclei unbound. So far, higher orders of the theory have been tested only in A<=3 nuclear systems, predominantly, due to nontrivial requirement of their perturbative inclusion. At three-body level, it has been shown that considering sub-leading terms systematically improves predictive power of the theory. Experimentally observed binding of A > 4 nuclei thus might be restored at higher orders.

 

In our work, we applied few-body approach based on the Stochastic Variational Method with a correlated Gaussian basis and a harmonic oscillator trap, which enabled us to study systems with A > 3. In this framework, we performed fully perturbative calculations within next-to-leading order (NLO) pionless EFT where perturbative calculations of A=4, 5 systems were performed for the first time. Our microscopic predictions of low-momentum n-d, n-3H, n-3He, and n-4He elastic scattering (scattering length and effective range) were compared to available experimental data and results of other theoretical predictions.