B. Indirect methods
There are many indirect methods that can be used in nuclear physics for astrophysics. We use a few of them, depending on the topic in our attention,
of the collaboration possibilities and the available beams. Most of these are with RIBs and here we include the spectroscopy of resonances (B1)
and the breakup of loosely bound proton-rich projectiles (B2), but there are cases in which stable beams are used, like
in the reactions studied with the Trojan Horse Method (B3) in collaboration with our Catania group collaborators.
In many cases one needs good theoretical descriptions and parameters (B4) of the reactions used to use information
obtained in indirect measurements at higher energies to estimate astrophysical S-factors or reaction rates at NA
relevant energies or temperatures.
B.1. Beta-delayed proton decay
The resonant capture of protons is a two-step process where the proton incident on a nucleus populates first a metastable state in the
compound nucleus (1st step) that then de-excites (2nd step) by gamma-ray emission.
The corresponding astrophysical reaction rates are given by the properties of the narrow,
isolated resonances only: spin and parity, energy, and resonant strength ωγ.
To study these resonances at astrophysical energies by direct measurements is not always easy or even possible.
An alternative is to populate the same metastable states and determine their spectroscopic properties by other means.
One way is the decay spectroscopy: we chose an exotic nucleus that will beta-decay to these same states.
These are schematically illustrated in Figure 3 below. The conditions were this is possible are listed on the left
and right sides of the figure: Q-values and the appropriate selection rules.
We have studied β-delayed proton decay (βp) at Texas A&M University using ASTROBOX2, an improved version of and
early gas detector ASTROBOX-1, both developed with TAMU and CEA/IRFU Saclay  A clone of this new detector is at
IFIN-HH, for use in European laboratories, ASTROBOX2E.
Resonance spectroscopy studies can be made using the beams from the 9 MV tandem-pelletron and the possibilities
of the RoSPHERE array, combining gamma-ray detectors and neutron detectors, e.g.
B.2. The breakup of 9C
In 2001 two of us proposed to use nuclear breakup data to determine the ANC (Asymptotic Normalization Coefficients)
for the breakup of nuclei Y->X+p and from there to evaluate the astrophysical S-factors for radiative proton capture
reactions X(p,g)Y. Important NA reactions data like S17  and S18  were evaluated using data from literature.
Later a dedicated experiment at GANIL was used to obtain NA data for the reactions 22Mg(p,γ)23Al and 23Al(p,γ)24Si .
In proposal NP1412-SAMURAI29R1 approved by the PAC of RIBF at RIKEN, Wako, Japan, we use the same scheme: we study
the nuclear and Coulomb breakup of 9C to evaluate the astrophysical S-factor for radiative proton capture on 8B.
The experiment was carried out in 2018 and the data are being analyzed.
B.3. Trojan Horse Method measurements
Trojan Horse Method was introduced and demonstrated as a valuable method for NA by the group of prof. Claudio Spitaleri from the University of Catania
and INFN LNS. They have proposed and test measurements were done in collaboration in Bucharest, at the 9 MV FN
tandem accelerator together with us to check if the reaction 12C + 12C can be studied using the Trojan Horse Method.
The reaction proposed was 12C(16O,α20Ne)α. The test was done using an 16O beam on 12C targets, but the answer was NO,
this reaction cannot be used because it turns out that the ground state of the projectile does not have a good clusterisation in
the α+12C channel. An alternative experiment using 14N beam was carried out at LNS Catania and resulted in important results . We continue this path for other reactions with light ion-ion fusion reactions in stars.
B.4. Optical Model Potentials for nucleus-nucleus collisions
We have a long-term program to understand and describe nucleus-nucleus collisions in terms of one interaction potential, the optical model potential (OMP). LT has worked on the problem for almost two decades with dr. F. Carstoiu.
The motivation is that a good understanding of all phenomena occurring in the elastic nucleus-nucleus scattering,
which are used typically to extract OMP, and the interpretation of the origin of different aspects, including
the well know potential ambiguities, are of crucial importance for finding and justifying the procedures used
for predicting nucleus-nucleus OMP in the era of radioactive nuclear beams (RNB) (see ours based on double folding
in Ref. 18). The reliability of these potentials is crucial in the correct description of reactions, from elastic
to transfer, to breakup, at energies ranging from a few to a few hundred MeV/nucleon. Of interest for us is to
support the absolute values of the calculated cross sections for reactions used in indirect methods for nuclear
astrophysics, see references  for some examples.
An exotic and recent subject can be considered the approach to cosmochemistry. Our group member Iuliana Stanciu is a PhD student on the topic
"Search for Supernova R-process actinides in fossilized reservoirs", PhD Supervisor Prof. Shawn Bishop, Physik-Department, E68,
Technische Universität München. An important part of her work is done in the institute, including a few other research departments.
C. Carpathian Summer Schools of Physics
NAG was and remains also instrumental in the organization of the most recent editions of the
Carpathian Summer Schools of Physics, a tradition that begun in 1964.
Seven latest editions were a series dedicated to nuclear and particle astrophysics, in relation
to exotic nuclei and to physics with small accelerators. The Carpathian school is part of the European
Network of Nuclear Astrophysics Schools (ENNAS), together with the European Summer School on
Experimental Nuclear Astrophysics, ESSENA (Catania, Italy) and the Russbach Winter School on
Nuclear Astrophysics, RWSNA (Russbach am Pass Gschütt, Austria). In agreement with those schools’
organizers, we created an established network of periodic events that responds to the need of
preparing and educating the younger generations of physicists in the cross disciplinary fields
of nuclear physics and astrophysics.
Below are links to the latest editions of CSSP:
The 2020 edition was scheduled for July 2020, but had to be canceled due to the coronavirus
crisis and will probably be postponed with exactly one year CSSP20: http://cssp20.nipne.ro/
The Proceedings of the schools were published, 6 of them with AIP Publishing.
The latest was published in 2019 
T1. Dense Matter Equation of State and Compact Objects
Cold mature nuclear stars are described by a one-parameter equation of state (EoS) that relates pressure
to energy density. In contrast, the studies of the dynamics of core-collapse supernovae (CCSN),
proto-neutron star (PNS) evolution, stellar black-hole (BH) formation and binary neutron star mergers
(BNS) require as an input an EoS at non-zero temperature and out of (weak) β-equilibrium, i.e.,
the pressure becomes a function of three thermodynamic parameters. For describing all of the above
mentioned astrophysical objects one needs to consider baryon number densities ranging from sub-saturation
densities up to several times the nuclear saturation density (10-15 < n < 10 fm-3),
temperatures 0 < T <100 MeV and charge fractions 0 < Yq < 0.6.
EoS of cold catalyzed matter with hyperonic degrees of freedom,
thermal evolution of isolated NS and accreting NS in quiescence,
development of finite temperature EoS with exotic degrees of freedom,
stability of NS with respect to gravitational collapse into BH,
universal scaling in hot star matter.
To the uncertainties related to the isoscalar and isovectorial channels of nuclear matter, add up uncertainties
related to the possible population of exotic degrees of freedom (strange baryons, baryonic resonances, condensates and quarks)
for which little experimental constraints exist despite significant experimental efforts.
The rapid progress of multi-messenger astrophysics allows one to constrain the neutron star (NS) EoS in domains
unattainable in our terrestrial laboratories.
In this context the study of dense matter’s EoS is of major interest for both nuclear physics and astrophysics communities.
Our research concerns:
Most recent publications are [21-25].
 Daniela Chesneanu, L. Trache, R. Margineanu, A. Pantelica, D. Ghita, M. Straticiuc, I. Burducea, A. M. Blebea-Apostu, C. M. Gomoiu, and X. Tang, AIP Conference Proceedings 1645, 311 (2015).
 I. Burducea, M. Straticiuc, D.G. Ghita, D.V. Mosu, C.I. Calinescu, N.C. Podaru, D.J.W. Mous, I. Ursu, N.V. Zamfir, Nuclear Instruments and Methods in Physics Research B 359, 1219, 2015.
 R. M. Margineanu, C. Simion, S. Bercea, O.G. Duliu, D. Gheorghiu, A. Stochioiuand, M. Matei, Appl. Radiat. Isot. 66, 1501(2008).
 D. Tudor, L. Trache, Alexandra I. Chilug, Ionut C. Stefanescu, Alexandra Spiridon, Mihai Straticiuc, Ion Burducea, Ana Pantelica, Romulus Margineanu,
Dan G. Ghita, Doru G. Pacesila, Radu F. Andrei, Claudia Gomoiu, Ning T. Zhang, Xiao D. Tang, Nucl. Instr. & Meth. in Phys. Res. A 953 (2020) 163178.
A facility for direct measurements for nuclear astrophysics at IFIN-HH -- a 3 MV tandem accelerator and an ultra-low background laboratory
 N. T. Zhang, X. Y. Wang, H. Chen, Z. J. Chen, W. P. Lin, W. Y. Xin, S. W. Xu, D. Tudor, A. I. Chilug, I. C. Stefanescu, M. Straticiuc,
I. Burducea, D. G. Ghita, R. Margineanu, C. Gomoiu, A. Pantelica, D. Chesneanu, L. Trache, X. D. Tang, B. Bucher, L. R. Gasques, K. Hagino,
S. Kubono, Y. J. Li, C. J. Lin , et al., Phys. Lett. B 801 (2020) 135170.
Constraining the 12C+12C astrophysical S-factors with the 12C+13C measurements at very low energies
 M. Arnould and S. Goriely, Physics Reports 384 (2003)1; https://doi.org/10.1016/S0370-1573(03)00242-4
 I. Cata-Danil et al., Phys. Rev. C 78, 035803 (2008); https://doi.org/10.1103/PhysRevC.78.035803
 D. Filipescu et al., Phys. Rev. C 83, 064609 (2011); https://doi.org/10.1103/PhysRevC.83.064609
 A. Oprea et al., EPJ Web of Conf. 146, 01016 (2017); https://doi.org/10.1051/epjconf/201714601016
 I. Gheorghe et al. Nucl. Data Sheets 119 (2014); https://doi.org/10.1016/j.nds.2014.08.067
 JR Huizenga and R. Vadenbosch, Phys. Rev. 120 (1960)1305; https://doi.org/10.1103/PhysRev.120.1305
 A.C. Larsen et al., Phys. Rev. C 83, 034315 (2011); https://doi.org/10.1103/PhysRevC.83.034315
 A. Saastamoinen, E. Pollacco, B.T. Roeder, A. Spiridon, M. Daq, L. Trache, G. Pascovici, R. Oliveira,
M.R.D. Rodrigues, R.E. Tribble, Nucl. Instr. & Meth. B 376. (2016) 357.
AstroBox2-Detector for low-energy beta-delayed particle detection
 L. Trache, F. Carstoiu, CA Gagliardi and RE Tribble, Phys. Rev. Lett. 87, 271102
(2001); ibidem, Phys. Rev. C 69, 032802 (2004).
 L. Trache, F. Carstoiu, CA Gagliardi and RE Tribble, Phys. Rev. C 66, 035801 (2002).
 A. Banu et al., Phys. Rev. C 84, 015803 (2011); Phys. Rev. C 86, 015806 (2012).
 A. Tumino, C. Spitaleri, M. La Cognata, S. Cherubini, G. L. Guardo, M. Gulino, S. Hayakawa,
I. Indelicato, L. Lamia, H. Petrascu, R. G. Pizzone, S. M. R. Puglia, G. G. Rapisarda, S. Romano,
M. L. Sergi, R. Spartá & L. Trache, Nature 557 Issue: 7707 Pages: 687 (2018). https://doi.org/10.1038/s41586-018-0149-4
An increase in the C-12+C-12 fusion rate from resonances at astrophysical energies
 L. Trache, F. Carstoiu et al. Phys. Rev. C 61, 024612 (2000).
 T. Al-Abdullah, F. Carstoiu, X. Chen, H. L. Clark, C. A. Gagliardi, Y.-W. Lui, A. Mukhamedzhanov,
G. Tabacaru, Y. Tokimoto, L. Trache, R. E. Tribble, and Y. Zhai, Phys. Rev. C 89, 025809 (2014);
ibidem Phys. Rev. C 89, 064602 (2014).
 Livius Trache and Alexandra Spiridon (eds.), Exotic nuclei and nuclear/particle astrophysics (vii) -
Physics with small accelerators. Proceedings of the Carpathian Summer School of Physics 2018 (CSSP18).
Book Series: American Institute of Physics Conference Proceedings, Volume: 2076, Melville, New York,
 A. Pascal, S. Giraud, A. Fantina, F. Gulminelli, J. Novak, M. Oertel, Ad. R. Raduta,
Phys. Rev. C 101, 015803 (2020).
Impact of electron capture rates on nuclei far from stability on core-collapse supernovae.
 M. Fortin, Ad. R. Raduta, S. Avancini, C. Providencia, Phys. Rev. D 101, 034017 (2020).
Relativistic hypernuclear compact stars with calibrated equations of state.
 Adriana R Raduta, Jia Jie Li, Armen Sedrakian, Fridolin Weber, MNRAS 487, 2639 (2019).
Cooling of hypernuclear compact stars: Hartree–Fock models and high-density pairing.
 Adriana R. Raduta, Armen Sedrakian and Fridolin Weber, MNRAS 475, 4347 (2018).
Cooling of hypernuclear compact stars.
 Ad.R.Raduta, F.Gulminelli, Nucl. Phys. A 983, 252 (2019).
Nuclear Statistical Equilibrium equation of state for core collapse.
Dr. Livius Trache
Prof. Adriana Raduta
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Dr. Dan Filipescu
Scientific Researcher II
Dr. Florin Carstoiu
(Department of Theoretical Physics)
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Dr. Ioana Gheorghe
Dr. Alexandra Elena Spiridon
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Dr. Andreea Oprea
PhD Student Alexandra Chilug
now IPA fellow RIKEN Nishina Center, Wako
PhD Student Dana Tudor
PhD Student Iuliana Stanciu
Currently at Technical University Munich
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Ionut Catalin Stefanescu, MS
now IPA fellow RIKEN Nishina Center, Wako
Madalina Ravar, MS
Currently at Univ. of Cologne-Bonn, Germany