Measurement of the α-Particle Monopole Transition Form Factor Challenges Theory: A Low-Energy Puzzle for Nuclear Forces?

We perform a systematic study of the α-particle excitation from its ground state 0_{1}^{+} to the 0_{2}^{+} resonance. The so-called monopole transition form factor is investigated via an electron scattering experiment in a broad Q^{2} range (from 0.5 to 5.

Probing the core of the strong nuclear interaction.

The strong nuclear interaction between nucleons (protons and neutrons) is the effective force that holds the atomic nucleus together. This force stems from fundamental interactions between quarks and gluons (the constituents of nucleons) that are described by the equations of quantum chromodynamics. However, as these equations cannot be solved directly, nuclear interactions are described using simplified models, which are well constrained at typical inter-nucleon distances but not at shorter distances.

Direct Observation of Proton-Neutron Short-Range Correlation Dominance in Heavy Nuclei.

We measured the triple coincidence A(e,e^{'}np) and A(e,e^{'}pp) reactions on carbon, aluminum, iron, and lead targets at Q^{2}>1.5  (GeV/c)^{2}, x_{B}>1.1 and missing momentum >400  MeV/c.

Four-Body Scale in Universal Few-Boson Systems.

The role of an intrinsic four-body scale in universal few-boson systems is the subject of active debate. We study these systems within the framework of effective field theory. For systems of up to six bosons we establish that no four-body scale appears at leading order (LO).

Resolving the Λ Hypernuclear Overbinding Problem in Pionless Effective Field Theory.

We address the Λ hypernuclear "overbinding problem" in light hypernuclei which stands for a 1-3 MeV excessive Λ separation energy calculated in _{Λ}^{5}He. This problem arises in most few-body calculations that reproduce ground-state Λ separation energies in the lighter Λ hypernuclei within various hyperon-nucleon interaction models. Recent pionless effective field theory (πEFT) nuclear few-body calculations are extended in this work to Λ hypernuclei.