I started studies with weakly bound beams, either of stable or radioactive nuclei, in 2002 and this subject is pursued by myself and our collaborators till today. This effort is led by my group in Ioannina, with a generous contribution in man power and equipment, by relevant collaborating laboratories from Greece and all over the world (the National and Kapodistrian University of Athens (NKUA), the University and INFN of Padova-Italy, INFN-Napoli-Italy, the University and INFN of Catania-Italy, the University of Huelva-Spain, and the Autonomous University of Mexico). The emphasis of this research is on the energy dependence of the optical potential, as well as on the reaction mechanisms at sub- and near-barrier energies.

Along the years, numerous experiments on elastic scattering, transfer, breakup and fusion reaction measurements were performed mainly with ^{6, 7}Li beams. The experimental data are interpreted in both a phenomenological approach, as well as in a CDCC framework with the contribution from the Andrzej Soltan Institute of Warsaw-Poland and the Universidad de Sevilla in Spain. Initially, our experiments with stable weakly bound beams were performed at NSCR Demokritos-Athens with collaborators both from NSCR and the National Technical University of Athens, followed by experiments performed at the Laboratori Nazionali del Sud (LNS) in Catania. One of our recent programs accomplished at the MAGNEX facility of LNS with the MAGNEX group, included a very interesting mapping of continuum in ^{6, 7}Li and ⁹Be nuclei, by using the elastic and inelastic scattering on protons in inverse kinematics.

Experiments with radioactive beams of ⁸Li, ⁷Be, ⁹B and ¹⁷F ions were performed at the EXOTIC facility of Legnaro-Italy and recently we initiated a program at the Twin Sol, upgraded to TriSol, facility of the University of Notre Dame-Indiana-USA. Elastic scattering and breakup measurements were performed with the radioactive beam of ⁷Be and the very appealing beam of ⁸B. A wealth of experimental findings were obtained at deep sub-barrier energies and near barrier energies on heavy and medium mass targets. Some of our results are included in two review articles in EPJA 57, 25 (2021) and EPJA 58, 8 (2022) and our suggested potential for light weakly bound nuclei on various targets and sub- and near- barrier energies in PRC109, 014609 (2024).

Prior to 2002, we have contributed to pioneering experiments performed by the Saclay group for the structure of ^{6, 8}He and implications in reaction mechanisms, as well as for experiments near the island of inversion with ³²Mg and ²⁷Ne beams.

We consider that the most intriguing features occur with the halo nuclei. In this case, the weak binding of the last nucleon or nucleons may lead to a wave function with an external tail extending far outside of the nuclear core as a result of quantum mechanical barrier penetration. This unusual structure, known as halo structure, by far exceeds the well-defined surface of a liquid drop model nucleus. One or more neutrons walk beyond the drop surface and form a misty cloud - a halo - with similarities to the electrons which form clouds around nuclei and make the atoms. In that context, halo nuclei are fragile objects, they are larger than standard, they interact easier with other nuclei (present enhanced reaction cross sections) and they present collective states in very low energies (soft dipole resonances). Such features can dramatically change our views for both the nuclear structure, the interaction potential and the origin of the cosmos. Predecessor studies to these of halo nuclei or in general to studies of radioactive nuclei, are obtained with weakly bound but stable nuclei. Of special interest are these of Borromean nuclei, as the ones that we performed with ⁹Be. Our scattering studies with ^{6, 7}Li and ⁹B to protons in inverse kinematics are in this direction, hoping such experiments to be expanded by the use of radioactive beams in the future.

Of great value, we consider our contribution to a campaign led by Prof. George Souliotis of the Chemistry Department of NKUA, initiated in the summer of 2018. In these studies, the production of neutron or/and proton rich elements is accomplished with multi-nucleon transfer reactions. As it was said before, the detailed study of exotic nuclei reveals important nuclear structure information beyond the standard models, as well as towards the effective nucleon interaction. The latter is fundamental for the accurate description of the nuclear equation of state of N/Z asymmetric nuclear matter which governs the physics of supernovae and neutron stars. In these reactions, medium mass nuclei very rich in neutron or/and proton are produced, via processes involving proton removal, neutron pickup or a combination of both, up to a triple charge exchange process, all trivially observed in our data. The reaction mechanisms of these processes, responsible for the production of neutron and proton rich nuclei, are also under exploration in our studies. The experiments are performed either with the MARS spectrometer of the Cyclotron Institute, Texas A&M University or at the MAGNEX facility at the National Nuclear Physics Laboratory of Catania. The goal of the measurements at LNS is also to extend the effective application of the spectrometer to heavy beams as ⁴⁸Ca, ⁷⁰Zn, ⁸⁶Kr on heavy n-rich targets, ⁶⁴Ni, ¹²⁴Sn and finally ²³⁸U. The first experiment with the study of the ⁷⁰Zn+⁶⁴Ni at 15MeV/nucleon, has opened the horizons in that direction, and with the upgrade of the MAGNEX facility, a systematic program with various projectiles and targets will be pursued, not only for the production of neutron and proton rich elements, but also for their interpretation in a reaction mechanism scheme.

Our collaboration within the NUMEN campaign started in April 2017 with a memorandum of understanding, signed by representatives of INFN-LNS, UOI, NKUA and the Hellenic Institute of Nuclear Physics at that time still in action. The main idea of the project is the fact that the processes underlying the netrinoless double-beta decay (0νββ-decay) are comparable with those governing DCE reactions, easier-to-observe in particular controllable environments: collisions between heavy, fast-moving ions. This idea ensured a generous European Funding for the upgrade of both the accelerator of the National Nuclear Physics Laboratory of Catania (INFN-LNS) and the MAGNEX facility, allowing the measurement at extremely high beam currents. This project represents the efforts of a global team of physicists. However, the core of the collaboration is the MAGNEX group of LNS, named after the MAGNEX spectrometer - the main detection equipment in these and many other experiments. Leader of the group is Prof. Francesco Cappuzzello and leaders of the project are Francesco Cappuzzello from the University of Catania and INFN-LNS and Dr Clementina Agodi from INFN-LNS.

First exploratory experiments with standard beam currents are multi-channel experiments, where all reaction channels are studied together with DCE. The advantage of multi-channel studies lies on the simultaneous measurement and theoretical interpretation of all. The upgrade of the facility, to be accomplished by the end of 2025, will ensure high beam currents and therefore the achievement of the appropriate statistics for rates rather low for the DCE channels. The interest of this research lies in the expectation that neutrinos can be of Majorana type, that is the same particle is particle and antiparticle. 0νββ-decay is potentially the best probe for observing or not a particle – the neutrino with its own antiparticle, as predicted by Majorana, and to extract their effective masses. Certainly, if this is proved, the balance between matter and antimatter will be violated in Nature. Of course till the deduction of the appropriate matrix elements for a neutrinoless double-beta decay, the steps both in technology and theory are many and challenging. However, our belief is that even in the worse scenario, we will build something important in science as “NUMEN is a challenging project at the intersection of nuclear and neutrino physics, driven by an important physics case and opening interesting scientific scenarios and potential technological fallout”.

I have performed g-factor measurements on stable nuclei in Oxford (1979-1982), Rutgers (1985-1988), Legnaro-Padova (1988-1990), Daresburry-Manchester (1991-1992), Berkeley-Rutgers (1999-2000).

From 1988-1992, I collaborated with the staff of NPL-Ioannina, in environmental studies concerning the:
a. transfer of radio-elements in plants and animals
b. countermeasures against the transfer of radio-elements in ruminants and
c. natural radioactivity

(complete publication list will be found in my CV and selected publications below)

• More than 180 papers in Scientific journals (citations 3300, h-factor 32)
• One text book in Experimental Methods of Nuclear Physics (in Greek)
• One translation of the text book: Concepts of Modern Physics by A. Beiser

From 1982-2013 before my early retirement, I have taught the following courses as a part of the Physics Department under graduate program:
• Modern Physics
• Experimental Methods in Nuclear Physics
• Nuclear Physics
• Laboratories in Modern Physics, Electromagnetism and Wave Mechanics
From 1999-2013, I have taught the course of Nuclear Physics as a part of the Physics Department post-graduate program.

• Former President of the Hellenic Nuclear Physics Society (HNPS)
• Former President of the Hellenic Institute of Nuclear Physics Society (HINP)
• Former Secretary of the Hellenic Institute of Nuclear Physics Society (HINP)
• Reviewer of EPJA, PRC, PRL
• Member of the American Physical Society (APS), Nuclear Physics European Collaboration Committee (NuPECC), HNPS, HINP

(in my early days)
• Onassis scholarship holder for PhD studies in Oxford
• Four times IKY (State Scholarship Foundation) scholarship holder for undergraduate studies
• Commendation with tuition fee waiver from St Hildas College-Oxford

1. A. Spatafora et al., “Multichannel experimental and theoretical approach to the single-charge-exchange reaction at 275 MeV. II. Competition between the meson exchange and the sequential transfer in the reaction mechanism” , Phys. Rev. C 110, 064612 (2024).
2. K. Palli et al., “Elastic scattering of ⁸B + ⁹⁰Zr nat at the sub-barrier energy of 26.5 MeV”, Phys. Rev. C 109, 064614 (2024).
3. A. Pakou, “Global optical potential for ⁷Be on various targets at sub- and near-barrier energies”, Phys. Rev. C 109, 014609 (2024).
4. S. Koulouris et al., “Multinucleon transfer channels from ⁷⁰Zn (15 MeV/nucleon) + ⁶⁴Ni collisions”, Phys. Rev. C 108, 044612 (2023).
5. O. Sgouros et al., “Global approach for the reactions ⁷Be + ²⁸Si and ⁷Be + ²⁰⁸Pb at near- and sub-barrier energies”, Phys. Rev. C 106, 044612(2022).
6. O. Sgouros, V. Soukeras, A. Pakou, “Low energy proton induced reactions with weakly bound nuclei for application purposes”, Eur. Phys. Journal A 57, 125 (2021)
7. A. Pakou et al., “Reaction mechanisms of the weakly bound nuclei, ^6,7Li and ^7,9Be on light targets at near barrier energies”, Eur. Phys. Journal A 58, 8 (2022) - review article.
8. A. Pakou et al., “Global descriptions and decay rates for continuum excitation of weakly bound nuclei”, Eur. Phys. Journal A 57, 25 (2021) - review article.
9. V. Soukeras et al., “Global study of ⁹Be+p at 2.72A MeV”, Phys. Rev. C 102, 064622 (2020).
10. A. Pakou et al., “Dominance of direct reaction channels at deep sub-barrier energies for weakly bound nuclei on heavy targets: The case ⁸B+²⁰⁸Pb”, Phys. Rev. C 102, 031601 (2020).
11. F. Cappuzzello et al., “The NUMEN project: NUclear Matrix Elements for Neutrinoless double beta decay”, Eur. Phys. Journal A 54, 72 (2018).
12. A. Pakou et al., “Global description of the ⁷Li+p reaction at 5.44 MeV/u in a continuum-discretized coupled-channels approach”, Phys. Rev. C 96, 034615 (2017).
13. A. Pakou et al., “Exclusive breakup of ⁷Li incident on a proton target at 5.44A MeV”, Phys. Rev. C 95, 044615 (2017).
14. C. Betsou et al., “Study of the ⁶Li+p->³He+⁴He reaction in inverse kinematics”, Eur. Phys. Journal A 51, 86 (2015).
15. A. Pakou et al., “Important influence of single neutron stripping coupling on near-barrier ⁸Li+⁹⁰Zr quasi-elastic scattering”, Eur. Phys. Journal A 51, 90 (2015).
16. O. Sgouros, V. Soukeras et al., “Backward angle structure in the ²⁰Ne+²⁸Si quasielastic scattering”, Int. Journal of Modern Physics E 22,1350073 (2013).
17. A. Pakou et al., “Fusion cross sections of ⁸B + ²⁸Si at near-barrier energies”, Phys. Rev. C 87, 014619 (2013).
18. K. Zerva et al., “Quasi-elastic backscattering of ^6,7Li on light, medium and heavy targets at near- and sub-barrier energies”, Eur. Phys. Journal A 48, 102 (2012).
19. A. Pakou et al., “Strong transfer channels in the ⁶Li+²⁸Si system at near-barrier energies”, Phys. Rev. C 76, 054601 (2007).
20. D. Roubos et al., “Radial sensitivity of elastic scattering at near barrier energies for weakly bound and tightly bound nuclei”, Phys. Rev. C 73, 051603 (2006).
21. A. Pakou et al., “The ⁶Li exclusive breakup on ²⁸Si at 13 MeV”, Phys. Lett. B 633, 691 (2006).
22. A. Pakou et al., “The elastic scattering of ⁶Li+²⁸Si at near-barrier energies”, Phys. Lett. B 556,21 (2003).
23. A. Pakou et al., “α-particle production in the reaction ⁶Li+²⁸Si at near-barrier energies”, Phys. Rev. Lett. 90, 202701 (2003).
24. N. Alamanos et al., “Sub-barrier and near-barrier fusion study of halo nuclei”, Phys. Rev. C 65, 546061 (2002).
25. A. Lagoyiannis et al., “Probing the ⁶He halo structure with elastic and inelastic proton scattering”, Phys. Lett. B 518, 27 (2001).
26. A. Pakou et al., “Isospin dependence of the microscopic JLM model”, Nuclear Physics A 691, 661 (2001).
27. A. Pakou et al., “Onset of collectivity in the ground-state band of ⁵⁰Cr”, Phys. Rev. C 50, 2608 (1994).
28. A. Pakou et al., “f_7/2 proton alignment in ⁴⁹Cr”, Phys. Rev. C 48, 1573 (1993).
29. A. Pakou et al., “X-ray production by Pt and Os projectiles moving in thick Fe targets with E=17−30 MeV”, Hyperfine Interactions 36, 253 (1987).
30. A. Pakou et al., “The g factors of the 5/2₁⁺ states in ¹⁵O and ¹⁵N”, Journal of Physics G 9, 1407 (1983).
31. De Raedt et al., “Velocity dependence of the transient magnetic field”, Hyperfine Interactions 9, 507 (1981).