New Results from the NUMEN Project

C. Agodi, F. Cappuzzello, L. Acosta, C. Altana, P. Amador-Valenzuela, N.
Auerbach, J. Barea, J.I. Bellone, R. Bijker, D. Bonanno, et al.

► To cite this version:

C. Agodi, F. Cappuzzello, L. Acosta, C. Altana, P. Amador-Valenzuela, et al. New Results from the NUMEN Project. 13th International Conference on Nucleus-Nucleus Collisions, Dec 2018, Omiya, Japan. pp.010045, 10.7566/JPSCP.32.010045. hal-02917256

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https://hal.science/hal-02917256

Submitted on 28 May 2024

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<figure><img src="image_1.png" /></figure>
# New Results from the NUMEN Project

C. Agodi, F. Cappuzzello, L. Acosta, C. Altana, P. Amador-Valenzuela, N. Auerbach, J. Barea, J.I. Bellone, R. Bijker, D. Bonanno, et al.

<figure><img src="image_1.png" /></figure>

► To cite this version:

C. Agodi, F. Cappuzzello, L. Acosta, C. Altana, P. Amador-Valenzuela, et al., New Results from the NUMEN Project. 13th International Conference on Nucleus-Nucleus Collisions, Dec 2018, Omiya, Japan. pp.010045, 10.7566/JPSCP.32.010045. [hal-02917256]

HAL Id: hal-02917256

https://hal.science/hal-02917256v1

Submitted on 28 May 2024

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_2.png" /></figure>
New Results From The NUMEN Project

C.Agodi<fnref n="1" />*<fnref n="1" />, F. Cappuzzello<fnref n="1" />,<fnref n="3" />, L. Acosta²⁰, C. Altana<fnref n="1" />, P. Amador-Valenzuela²¹, N.Auerbach²⁷, J. Barea³⁴, J.I. Bellone<fnref n="1" />, R. Bijker²², D. Bonanno<fnref n="2" />, T. Borello-Lewin<fnref n="14" />, I. Boztosun²⁵, V. Branchina<fnref n="2" />,<fnref n="3" />, S. Brasolin<fnref n="4" />, G. Brischetto<fnref n="1" />,<fnref n="3" />,<fnref n="5" />, O. Brunasso<fnref n="4" />, S. Burrello<fnref n="1" />, S. Calabrese<fnref n="1" />,<fnref n="3" />, L. Calabretta<fnref n="1" />, D. Calvo<fnref n="4" />, V. Capirossi<fnref n="4" />,<fnref n="6" />, D. Carbone<fnref n="1" />, M. Cavallaro<fnref n="1" />, R. Chen³³, L.E. Charon Garcia²⁰, E.R. Chávez Lomelí²⁰, I. Ciraldo<fnref n="1" />,<fnref n="3" />, M. Colonna<fnref n="1" />, G. D'Agostino<fnref n="1" />, H. Djapo²⁵, G. De Geronimo³², F. Delaunay<fnref n="4" />,<fnref n="6" />,<fnref n="12" />, K. De Los Rios²⁰, N. Deshmukh³⁰, C. Ferraresi<fnref n="4" />,<fnref n="7" />, J.L. Ferreira<fnref n="15" />, J. Ferretti<fnref n="8" />,<fnref n="13" />, P. Finocchiaro<fnref n="1" />, S. Firat²⁵, M. Fisichella<fnref n="4" />, A. Foti<fnref n="2" />, G. Gallo<fnref n="1" />,<fnref n="3" />, H. Garcia-Tecocoatzi<fnref n="8" />,<fnref n="9" />, A. Hacisalihoglu²⁶, A. Huerta-Hernandez²⁰, J. Kotila³¹, Y. Kucuk²⁵, F. Iazzi<fnref n="4" />,<fnref n="6" />, L. La Fauci<fnref n="1" />,<fnref n="3" />, G. Lanzalone<fnref n="1" />,<fnref n="10" />, F. La Via<fnref n="11" />, J.A. Lay²⁸, H. Lenske²³, R. Linares<fnref n="15" />,D. Lo Presti<fnref n="2" />,<fnref n="3" />, J. Lubian<fnref n="15" />, J. Ma³³, D. Marín-Lámbarri²⁰, J. Mas Ruiz²⁰, N. H. Medina<fnref n="14" />, D.R. Mendes<fnref n="15" />, P. Mereu<fnref n="4" />, M. Moralles<fnref n="16" />, L. Neri<fnref n="1" />, J. R. B. Oliveira<fnref n="14" />, A. Pakou¹⁸, L. Pandola<fnref n="1" />, H. Petrascu²⁹, N. Pietralla²⁴, F. Pinna<fnref n="4" />,<fnref n="6" />, S. Reito<fnref n="2" />, P. Ries²⁴, M.R.D. Rodrigues<fnref n="14" />, A. D. Russo<fnref n="1" />, G. Russo<fnref n="2" />,<fnref n="3" />, E. Santopinto<fnref n="8" />, R.B.B. Santos<fnref n="17" />, L. Serbina²⁹, O. Sgouros<fnref n="1" />, M.A.G. da Silveira<fnref n="17" />, S.O. Solakci²⁵, G. Souliotis¹⁹,V. Soukeras<fnref n="1" />, A. Spatafora<fnref n="1" />,<fnref n="3" />, D. Torresi<fnref n="1" />, S. Tudisco<fnref n="1" />, R.I.M. Vsevolodovna<fnref n="8" />,<fnref n="9" />, H. Vargas Hernandez²⁰, J.S. Wang³³, V. Werner²⁴, Y.Y. Yang³³, A. Yildirim²⁵, V.A.B. Zagatto<fnref n="15" /> for the NUMEN collaboration

<figure><img src="image_2.png" /></figure>

<footnote n="1">¹ Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Italy</footnote>

<footnote n="2">² Istituto Nazionale di Fisica Nucleare, Sezione di Catania, Italy</footnote>

<footnote n="3">³ Dipartimento di Fisica e Astronomia "Ettore Majorana", Università di Catania, Italy</footnote>

<footnote n="4">⁴ Istituto Nazionale di Fisica Nucleare, Sezione di Torino, Italy</footnote>

<footnote n="5">⁵ Centro Siciliano di Fisica Nucleare e Struttura della Materia, Italy</footnote>

<footnote n="6">⁶ DISAT, Politecnico di Torino, Italy</footnote>

<footnote n="7">⁷ DIMEAS, Politecnico di Torino, Italy</footnote>

<footnote n="8">⁸ Istituto Nazionale di Fisica Nucleare, Sezione di Genova, Italy</footnote>

<footnote n="9">⁹ Dipartimento di Fisica, Università di Genova, Italy</footnote>

<footnote n="10">¹⁰ Università degli Studi di Enna "Kore", Italy</footnote>

<footnote n="11">¹¹ CNR-IMM, Sezione di Catania, Italy</footnote>

<footnote n="12">¹² LPC Caen, Normandie Université, ENSICAEN, UNICAEN, CNRS/INP3, France</footnote>

<footnote n="13">¹³ Department of Physics, Yale University, USA</footnote>

<footnote n="14">¹⁴ Instituto de Fisica, Universidade de Sao Paulo, Brazil</footnote>

<footnote n="15">¹⁵ Instituto de Fisica, Universidade Federal Fluminense, Brazil</footnote>

<footnote n="16">¹⁶ Instituto de Pesquisas Energeticas e Nucleares IPEN/CNEN, Brazil</footnote>

<footnote n="17">¹⁷ Centro Universitario FEI Sao Bernardo do Campo, Brazil</footnote>
New Results From The NUMEN Project

C.Agodi<fnref n="1" />*<fnref n="1" />, F. Cappuzzello<fnref n="1" />,<fnref n="3" />, L. Acosta²⁰, C. Altana<fnref n="1" />, P. Amador-Valenzuela²¹, N.Auerbach²⁷, J. Barea³⁴, J.I. Bellone<fnref n="1" />, R. Bijker²², D. Bonanno<fnref n="2" />, T. Borello-Lewin<fnref n="14" />, I. Boztosun²⁵, V. Branchina<fnref n="2" />,<fnref n="3" />, S. Brasolin<fnref n="4" />, G. Brischetto<fnref n="1" />,<fnref n="3" />,<fnref n="5" />, O. Brunasso<fnref n="4" />, S. Burrello<fnref n="1" />, S. Calabrese<fnref n="1" />,<fnref n="3" />, L. Calabretta<fnref n="1" />, D. Calvo<fnref n="4" />, V. Capirossi<fnref n="4" />,<fnref n="6" />, D. Carbone<fnref n="1" />, M. Cavallaro<fnref n="1" />, R. Chen³³, L.E. Charon Garcia²⁰, E.R. Chávez Lomelí²⁰, I. Ciraldo<fnref n="1" />,<fnref n="3" />, M. Colonna<fnref n="1" />, G. D'Agostino<fnref n="1" />, H. Djapo²⁵, G. De Geronimo³², F. Delaunay<fnref n="4" />,<fnref n="6" />,<fnref n="12" />, K. De Los Rios²⁰, N. Deshmukh³⁰, C. Ferraresi<fnref n="4" />,<fnref n="7" />, J.L. Ferreira<fnref n="15" />, J. Ferretti<fnref n="8" />,<fnref n="13" />, P. Finocchiaro<fnref n="1" />, S. Firat²⁵, M. Fisichella<fnref n="4" />, A. Foti<fnref n="2" />, G. Gallo<fnref n="1" />,<fnref n="3" />, H. Garcia-Tecocoatzi<fnref n="8" />,<fnref n="9" />, A. Hacisalihoglu²⁶, A. Huerta-Hernandez²⁰, J. Kotila³¹, Y. Kucuk²⁵, F. Iazzi<fnref n="4" />,<fnref n="6" />, L. La Fauci<fnref n="1" />,<fnref n="3" />, G. Lanzalone<fnref n="1" />,<fnref n="10" />, F. La Via<fnref n="11" />, J.A. Lay²⁸, H. Lenske²³, R. Linares<fnref n="15" />,D. Lo Presti<fnref n="2" />,<fnref n="3" />, J. Lubian<fnref n="15" />, J. Ma³³, D. Marín-Lámbarri²⁰, J. Mas Ruiz²⁰, N. H. Medina<fnref n="14" />, D.R. Mendes<fnref n="15" />, P. Mereu<fnref n="4" />, M. Moralles<fnref n="16" />, L. Neri<fnref n="1" />, J. R. B. Oliveira<fnref n="14" />, A. Pakou¹⁸, L. Pandola<fnref n="1" />, H. Petrascu²⁹, N. Pietralla²⁴, F. Pinna<fnref n="4" />,<fnref n="6" />, S. Reito<fnref n="2" />, P. Ries²⁴, M.R.D. Rodrigues<fnref n="14" />, A. D. Russo<fnref n="1" />, G. Russo<fnref n="2" />,<fnref n="3" />, E. Santopinto<fnref n="8" />, R.B.B. Santos<fnref n="17" />, L. Serbina²⁹, O. Sgouros<fnref n="1" />, M.A.G. da Silveira<fnref n="17" />, S.O. Solakci²⁵, G. Souliotis¹⁹,V. Soukeras<fnref n="1" />, A. Spatafora<fnref n="1" />,<fnref n="3" />, D. Torresi<fnref n="1" />, S. Tudisco<fnref n="1" />, R.I.M. Vsevolodovna<fnref n="8" />,<fnref n="9" />, H. Vargas Hernandez²⁰, J.S. Wang³³, V. Werner²⁴, Y.Y. Yang³³, A. Yildirim²⁵, V.A.B. Zagatto<fnref n="15" /> for the NUMEN collaboration

<figure><img src="image_3.png" /></figure>

<footnote n="1">¹ Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Italy</footnote>

<footnote n="2">² Istituto Nazionale di Fisica Nucleare, Sezione di Catania, Italy</footnote>

<footnote n="3">³ Dipartimento di Fisica e Astronomia "Ettore Majorana", Università di Catania, Italy</footnote>

<footnote n="4">⁴ Istituto Nazionale di Fisica Nucleare, Sezione di Torino, Italy</footnote>

<footnote n="5">⁵ Centro Siciliano di Fisica Nucleare e Struttura della Materia, Italy</footnote>

<footnote n="6">⁶ DISAT, Politecnico di Torino, Italy</footnote>

<footnote n="7">⁷ DIMEAS, Politecnico di Torino, Italy</footnote>

<footnote n="8">⁸ Istituto Nazionale di Fisica Nucleare, Sezione di Genova, Italy</footnote>

<footnote n="9">⁹ Dipartimento di Fisica, Università di Genova, Italy</footnote>

<footnote n="10">¹⁰ Università degli Studi di Enna "Kore", Italy</footnote>

<footnote n="11">¹¹ CNR-IMM, Sezione di Catania, Italy</footnote>

<footnote n="12">¹² LPC Caen, Normandie Université, ENSICAEN, UNICAEN, CNRS/INP3, France</footnote>

<footnote n="13">¹³ Department of Physics, Yale University, USA</footnote>

<footnote n="14">¹⁴ Instituto de Fisica, Universidade de Sao Paulo, Brazil</footnote>

<footnote n="15">¹⁵ Instituto de Fisica, Universidade Federal Fluminense, Brazil</footnote>

<footnote n="16">¹⁶ Instituto de Pesquisas Energeticas e Nucleares IPEN/CNEN, Brazil</footnote>

<footnote n="17">¹⁷ Centro Universitario FEI Sao Bernardo do Campo, Brazil</footnote>
<sup>18</sup>Department of Physics and HINP, University of Ioannina, Greece

<sup>19</sup>Department of Chemistry, National and Kapodistrian University of Athens, Greece

<sup>20</sup>Instituto de Fisica, Universidad Nacional Autónoma de México, Mexico

<sup>21</sup>Instituto Nacional de Investigaciones Nucleares, Mexico

<sup>22</sup>Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Mexico

<sup>23</sup>Department of Physics, University of Giessen, Germany

<sup>24</sup>Institut fur Kernphysik, Technische Universitat Darmstadt, Germany

<sup>25</sup>Department of Physics, Akdeniz University, Turkey

<sup>26</sup>Institute of Natural Sciences, Karadeniz Teknik University, Turkey

<sup>27</sup>School of Physics and Astronomy, Tel Aviv University, Israel

<sup>28</sup>Departamento de FAMN, University of Seville, Spain

<sup>29</sup>Department of Nuclear Physics, Horia Hubulei National Institute of Physics and Nuclear Engineering, IFIN-HH, Romania

<sup>30</sup>Nuclear Physics Division, Saha Institute of Nuclear Physics, India

<sup>31</sup>University of Jyväskylä, Finland

<sup>32</sup>Stony Brook University, USA

<sup>33</sup>Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China

<sup>34</sup>Departamento de Fisica, Universidad de Conception, Chile

*E-mail: agodi@lns.infn.it

Received July 20, 2019

NUMEN aims at accessing experimentally driven information on Nuclear Matrix Elements (NME) involved in the half-life of the neutrinoless double beta decay (0vββ), by high-accuracy measurements of the cross sections of Heavy Ion (HI) induced Double Charge Exchange (DCE) reactions. First evidence about the possibility to get quantitative information about NME from experiments is found for the (¹⁸O,¹⁸Ne) and (²⁰Ne,²⁰O) reactions. Moreover, to infer the neutrino average masses from the possible measurement of the half-life of 0vββ decay, the knowledge of the NME is a crucial aspect. The key tools for this project are the high resolution Superconducting Cyclotron beams and the MAGNEX magnetic spectrometer at INFN Laboratori Nazionali del Sud in Catania (Italy). The measured cross sections are extremely low, limiting the present exploration to few selected isotopes of interest in the context of typically low-yield experimental runs. A major upgrade of the LNS facility is foreseen in order to increase the experimental yield of at least two orders of magnitude, thus making feasible a systematic study of all the cases of interest.

**KEYWORDS:** Heavy Ions Double Charge Exchange reactions, neutrinoless double beta decay, Nuclear Matrix Elements, Nuclear Reactions, Nuclear structure, magnetic spectrometer, cyclotron, NUMEN project

# 1. Introduction

The search for neutrinoless double beta decay (0vββ) addresses fundamental questions in physics, related to the absolute neutrinos mass scale, whether neutrinos are Majorana particles or how many neutrino species are there. Moreover 0vββ search has implications for the understanding of the matter-antimatter asymmetry in the universe. The design of the 0vββ search experiments themselves require detailed understanding of nuclear physics, as backgrounds critically depend on nuclear decay chain and nuclear
<sup>18</sup>Department of Physics and HINP, University of Ioannina, Greece

<sup>19</sup>Department of Chemistry, National and Kapodistrian University of Athens, Greece

<sup>20</sup>Instituto de Fisica, Universidad Nacional Autónoma de México, Mexico

<sup>21</sup>Instituto Nacional de Investigaciones Nucleares, Mexico

<sup>22</sup>Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Mexico

<sup>23</sup>Department of Physics, University of Giessen, Germany

<sup>24</sup>Institut fur Kernphysik, Technische Universitat Darmstadt, Germany

<sup>25</sup>Department of Physics, Akdeniz University, Turkey

<sup>26</sup>Institute of Natural Sciences, Karadeniz Teknik University, Turkey

<sup>27</sup>School of Physics and Astronomy, Tel Aviv University, Israel

<sup>28</sup>Departamento de FAMN, University of Seville, Spain

<sup>29</sup>Department of Nuclear Physics, Horia Hubulei National Institute of Physics and Nuclear Engineering, IFIN-HH, Romania

<sup>30</sup>Nuclear Physics Division, Saha Institute of Nuclear Physics, India

<sup>31</sup>University of Jyväskylä, Finland

<sup>32</sup>Stony Brook University, USA

<sup>33</sup>Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China

<sup>34</sup>Departamento de Fisica, Universidad de Conception, Chile

*E-mail: agodi@lns.infn.it

Received July 20, 2019

NUMEN aims at accessing experimentally driven information on Nuclear Matrix Elements (NME) involved in the half-life of the neutrinoless double beta decay (0vββ), by high-accuracy measurements of the cross sections of Heavy Ion (HI) induced Double Charge Exchange (DCE) reactions. First evidence about the possibility to get quantitative information about NME from experiments is found for the (¹⁸O,¹⁸Ne) and (²⁰Ne,²⁰O) reactions. Moreover, to infer the neutrino average masses from the possible measurement of the half-life of 0vββ decay, the knowledge of the NME is a crucial aspect. The key tools for this project are the high resolution Superconducting Cyclotron beams and the MAGNEX magnetic spectrometer at INFN Laboratori Nazionali del Sud in Catania (Italy). The measured cross sections are extremely low, limiting the present exploration to few selected isotopes of interest in the context of typically low-yield experimental runs. A major upgrade of the LNS facility is foreseen in order to increase the experimental yield of at least two orders of magnitude, thus making feasible a systematic study of all the cases of interest.

**KEYWORDS:** Heavy Ions Double Charge Exchange reactions, neutrinoless double beta decay, Nuclear Matrix Elements, Nuclear Reactions, Nuclear structure, magnetic spectrometer, cyclotron, NUMEN project

# 1. Introduction

The search for neutrinoless double beta decay (0vββ) addresses fundamental questions in physics, related to the absolute neutrinos mass scale, whether neutrinos are Majorana particles or how many neutrino species are there. Moreover 0vββ search has implications for the understanding of the matter-antimatter asymmetry in the universe. The design of the 0vββ search experiments themselves require detailed understanding of nuclear physics, as backgrounds critically depend on nuclear decay chain and nuclear
matrix elements are needed to link observed rates to neutrino properties.

In this framework the NUMEN project proposes an innovative and original tool: to use HI-DCE reactions to access quantitative informations for NME towards $0v\beta\beta$ decay.

## 2. The NUMEN project

The NUMEN main goal is the extraction from measured cross-sections of “data-driven” information on NME for all systems candidate for $0v\beta\beta$. Crucial for the experimental challenges is the INFN LNS facility, made by the CS and the MAGNEX magnetic spectrometer. The experimental measurements of HI-DCE reactions present a number of challenging aspects, since they are characterized by very low cross sections and, in the same experimental conditions, had to be isolated among the different competitive reaction channels.

It is well known that the $0v\beta\beta$ half-life can be factorized in three terms at different physics scale: the phase-space factor, connected with Atomic physics, the Matrix Element (NME) related with Nuclear physics and a term, related to Particle physics, in which it is supposed there are the answers to the unsolved questions, related to new physics beyond the Standard Model. For evaluation of NME several methods have been used, based on different nuclear models, an updated comparison of the results of NME calculations, obtained within various nuclear structure frameworks [1-4], indicates that significant differences are indeed found. In addition, some assumption common to different competing approaches could cause overall systematic uncertainties.

NUMEN [5, 6] proposes a novel way to address experimentally-driven information on the NMEs of $0v\beta\beta$, based on DCE cross section measurements. These reactions are characterized by the transfer of two charge units, leaving the mass number unchanged, and can proceed either by a sequential multi-nucleon-transfer mechanism or by meson-exchange. Despite $0v\beta\beta$ decays and HI-DCE reactions are mediated by different interactions, they present a number of similarities, among the others: the initial and final state wave functions in the two processes are the same.

MAGNEX is a large acceptance magnetic system able to provide high resolution in energy, mass and angle [7] and an accurate control of the detection efficiency. The implementation of trajectory reconstruction technique is the key feature of MAGNEX, which guarantees the above mentioned performance and its relevance in the research for heavy-ion physics [8-10], also taking advantage of its coupling to the EDEN neutron detector array [11,12]. At the this facility we demonstrate the feasibility of this kind of DCE cross sections measurements, with $^{40}$Ca($^{18}$O,$^{18}$Ne)$^{40}$Ar reaction, that was studied at 15 MeV/u, see ref. [13]. This result demonstrated that the previous experimental limitations are almost overcome and that high resolution and statistically significant experimental data can be measured for DCE processes. In the present experimental conditions, due to the limitation arising from the tiny cross-sections of the processes of interest, only very few systems can be measured. In order to systematically explore all the nuclei candidates for $0v\beta\beta$, a beam intensity at least two orders of magnitude higher than the present must be achieved. NUMEN is conceived in a long-range time perspective, in view of a comprehensive study of many candidate systems for $0v\beta\beta$.
matrix elements are needed to link observed rates to neutrino properties.

In this framework the NUMEN project proposes an innovative and original tool: to use HI-DCE reactions to access quantitative informations for NME towards $0v\beta\beta$ decay.

## 2. The NUMEN project

The NUMEN main goal is the extraction from measured cross-sections of “data-driven” information on NME for all systems candidate for $0v\beta\beta$. Crucial for the experimental challenges is the INFN LNS facility, made by the CS and the MAGNEX magnetic spectrometer. The experimental measurements of HI-DCE reactions present a number of challenging aspects, since they are characterized by very low cross sections and, in the same experimental conditions, had to be isolated among the different competitive reaction channels.

It is well known that the $0v\beta\beta$ half-life can be factorized in three terms at different physics scale: the phase-space factor, connected with Atomic physics, the Matrix Element (NME) related with Nuclear physics and a term, related to Particle physics, in which it is supposed there are the answers to the unsolved questions, related to new physics beyond the Standard Model. For evaluation of NME several methods have been used, based on different nuclear models, an updated comparison of the results of NME calculations, obtained within various nuclear structure frameworks [1-4], indicates that significant differences are indeed found. In addition, some assumption common to different competing approaches could cause overall systematic uncertainties.

NUMEN [5, 6] proposes a novel way to address experimentally-driven information on the NMEs of $0v\beta\beta$, based on DCE cross section measurements. These reactions are characterized by the transfer of two charge units, leaving the mass number unchanged, and can proceed either by a sequential multi-nucleon-transfer mechanism or by meson-exchange. Despite $0v\beta\beta$ decays and HI-DCE reactions are mediated by different interactions, they present a number of similarities, among the others: the initial and final state wave functions in the two processes are the same.

MAGNEX is a large acceptance magnetic system able to provide high resolution in energy, mass and angle [7] and an accurate control of the detection efficiency. The implementation of trajectory reconstruction technique is the key feature of MAGNEX, which guarantees the above mentioned performance and its relevance in the research for heavy-ion physics [8-10], also taking advantage of its coupling to the EDEN neutron detector array [11,12]. At the this facility we demonstrate the feasibility of this kind of DCE cross sections measurements, with $^{40}$Ca($^{18}$O,$^{18}$Ne)$^{40}$Ar reaction, that was studied at 15 MeV/u, see ref. [13]. This result demonstrated that the previous experimental limitations are almost overcome and that high resolution and statistically significant experimental data can be measured for DCE processes. In the present experimental conditions, due to the limitation arising from the tiny cross-sections of the processes of interest, only very few systems can be measured. In order to systematically explore all the nuclei candidates for $0v\beta\beta$, a beam intensity at least two orders of magnitude higher than the present must be achieved. NUMEN is conceived in a long-range time perspective, in view of a comprehensive study of many candidate systems for $0v\beta\beta$.
decay. Moreover, the project promotes a renewal of the INFN-LNS research infrastructure with a specific R&D activity on the accelerator, the detectors, materials and instrumentation. For the accelerator the change of the beam extraction technology from electrostatic deflector to a stripper foil is an adequate choice [14]. For the spectrometer the main foreseen upgrades are:

1. The substitution of the present focal plane detector (FPD) gas tracker, based on multiplication wire technology with a tracker system based on micro patterned gas detector [15,16];

2. The substitution of the wall of silicon pad stopping detectors with telescopes of SiC-CsI detectors [17,18] or similar [19];

3. The introduction of an array of scintillators for measuring the coincident γ-rays [20], using the experience on studies of different scintillators materials [21];

4. The development of suitable front-end and read-out electronics, capable to guarantee a fast read-out of the detector signals, still preserving a high signal to noise ratio and guaranteeing enough hardness to radiation [22,23];

5. Develop a suitable architecture for data acquisition, storage and data handling, including accurate detector response simulations;

6. The enhancement of the maximum accepted magnetic rigidity, preserving the geometry and field uniformity of the magnetic field [24-25] in order to keep the high-precision of the present trajectory reconstruction;

7. The installation of a beam dump to stop the high power beams, keeping the generated radioactivity under control.

In addition, we are developing the technology for suitable nuclear targets to be used in the experiments. Here the challenge is to produce and cool isotopically enriched thin films able to resist to the high power dissipated by the interaction of the intense beams with the target material [26-27].

Moreover, a deep and complete investigation of the theoretical aspects connecting nuclear reaction mechanisms and nuclear matrix elements must be carried out [28, 30]. With the present facility and experimental setup we perform some long run at LNS with MAGNEX, choosing few isotopes, candidates for $0vββ$, already at our reach in terms of energy resolution and availability of thin targets. In particular, we performed for the first time experimental investigations of the ($^{20}$Ne,$^{20}$O) DCE reaction on $^{116}$Cd,$^{76}$Ge and $^{130}$Te targets. These are the first measurements of such a kind of reaction: no data are available in literature. For the $^{116}$Cd-$^{116}$Sn and $^{76}$Ge-$^{76}$Se pairs, the ground states are resolved from excited states by MAGNEX for both ($^{18}$O,$^{18}$Ne) and ($^{20}$Ne,$^{20}$O) reactions [31]. Despite the experimental limitations, we were able to measure energy spectra and absolute cross sections for the DCE reaction channel. Moreover, we measured also other reaction channels: one- and two-proton transfer, one- and two-neutron transfer and Single Charge Exchange, in order to estimate the role of the sequential multi-nucleon transfer routes on the diagonal DCE process.

### 3. Conclusion

Pioneering experiments on ($^{18}$O,$^{18}$Ne) and ($^{20}$Ne,$^{20}$O) DCE performed at INFN-LNS
decay. Moreover, the project promotes a renewal of the INFN-LNS research infrastructure with a specific R&D activity on the accelerator, the detectors, materials and instrumentation. For the accelerator the change of the beam extraction technology from electrostatic deflector to a stripper foil is an adequate choice [14]. For the spectrometer the main foreseen upgrades are:

1. The substitution of the present focal plane detector (FPD) gas tracker, based on multiplication wire technology with a tracker system based on micro patterned gas detector [15,16];

2. The substitution of the wall of silicon pad stopping detectors with telescopes of SiC-CsI detectors [17,18] or similar [19];

3. The introduction of an array of scintillators for measuring the coincident γ-rays [20], using the experience on studies of different scintillators materials [21];

4. The development of suitable front-end and read-out electronics, capable to guarantee a fast read-out of the detector signals, still preserving a high signal to noise ratio and guaranteeing enough hardness to radiation [22,23];

5. Develop a suitable architecture for data acquisition, storage and data handling, including accurate detector response simulations;

6. The enhancement of the maximum accepted magnetic rigidity, preserving the geometry and field uniformity of the magnetic field [24-25] in order to keep the high-precision of the present trajectory reconstruction;

7. The installation of a beam dump to stop the high power beams, keeping the generated radioactivity under control.

In addition, we are developing the technology for suitable nuclear targets to be used in the experiments. Here the challenge is to produce and cool isotopically enriched thin films able to resist to the high power dissipated by the interaction of the intense beams with the target material [26-27].

Moreover, a deep and complete investigation of the theoretical aspects connecting nuclear reaction mechanisms and nuclear matrix elements must be carried out [28, 30]. With the present facility and experimental setup we perform some long run at LNS with MAGNEX, choosing few isotopes, candidates for $0\nu\beta\beta$, already at our reach in terms of energy resolution and availability of thin targets. In particular, we performed for the first time experimental investigations of the ($^{20}$Ne,$^{20}$O) DCE reaction on $^{116}$Cd,$^{76}$Ge and $^{130}$Te targets. These are the first measurements of such a kind of reaction: no data are available in literature. For the $^{116}$Cd-$^{116}$Sn and $^{76}$Ge-$^{76}$Se pairs, the ground states are resolved from excited states by MAGNEX for both ($^{18}$O,$^{18}$Ne) and ($^{20}$Ne,$^{20}$O) reactions [31]. Despite the experimental limitations, we were able to measure energy spectra and absolute cross sections for the DCE reaction channel. Moreover, we measured also other reaction channels: one- and two-proton transfer, one- and two-neutron transfer and Single Charge Exchange, in order to estimate the role of the sequential multi-nucleon transfer routes on the diagonal DCE process.

### 3. Conclusion

Pioneering experiments on ($^{18}$O,$^{18}$Ne) and ($^{20}$Ne,$^{20}$O) DCE performed at INFN-LNS
in Catania have shown that accurate cross sections measurements at very forward angles can be done. The main activity characterizing the NUMEN project is the measurement of DCE absolute cross sections, with the related processes, and the extraction of relevant NMEs. The NUMEN “Holy Graal” is to find a connection between the NMEs extracted from DCE reactions and those characterizing $0v\beta\beta$ decay. NUMEN is a big challenge both for nuclear technology and nuclear theory. Moreover it promotes an important upgrade of the experimental facilities and the development of the different theoretical aspects, connected with the nuclear structure and reaction mechanisms, involved in heavy ions induced in DCE reactions. High intensity beams are the new frontier for these challenging studies. NUMEN indicates a possible growth prospect of heavy-ion physics in synergy with neutrino physics, aims at giving an innovative contribution in one of the most promising fields of fundamental physics.

References

[1] J. D. Vergados et al., Reports on Progress in Physics 75, 106301 (2012).

[2] P. Vogel, Jour. of Phys. G 39, 124002 (2012).

[3] J. Barea, J. Kotila, F. Iachello, Phys. Rev. Lett. 109, 042501 (2012).

[4] S. Dell'Oro et al., Advances in High Energy Physics 2016, 216259 (2016).

[5] F. Cappuzzello et al., Eur. Phys. J. A 54, 72 (2018).

[6] C. Agodi et al., Nucl. Part. Phys. Proc. 265, 28 (2015).

[7] F. Cappuzzello et al., Eur. Phys. J. A 52, 167 (2015).

[8] F. Cappuzzello et al., Nature Communications 6, 6743 (2015).

[9] D. Carbone et al., Phys. Rev. C 95, 034603 (2017).

[10] J. R. B. Oliveira et al., J. Phys. G 40, 105101 (2013).

[11] M. Cavallaro et al., Phys. Rev. C 93, 064323 (2016).

[12] M. Cavallaro et al., Nucl. Instr. and Meth. A 700, 65 (2013).

[13] F. Cappuzzello et al., Eur. Phys. J. A 51, 145 (2015).

[14] L. Calabretta et al., Modern Physics Letters A 32, 17 (2017).

[15] M. Cortesi et al., Review of Scientific Instruments 88, 013303 (2017).

[16] D. Lo Presti et al., J. Phys. Conf. Ser. 18, 012034 (2018).

[17] S. Tudisco et al., Sensors 18, 2289 (2018).

[18] A. Muoio et al., EPJ Web of Conferences 117, 10006 (2016).

[19] D. Carbone et al., Results in Physics 6, 863-865 (2016).

[20] J. R. B. Oliveira et al., J. Phys. Conf. Ser. 18, 012040 (2018).

[21] C. Agodi et al., Nucl. Instr. and Meth. A 269 (3), 595-598 (1988).

[22] G. De Geronimo et al., IEEE Transactions on Nuclear Science, 60 2314-2321 (2013).

[23] D. Bonanno et al., J. Phys. Conf. Ser. 18 012006 (2018).

[24] A. Lazzaro et al., Nucl. Instr. and Methods A, 591 394 (2008).

[25] A. Lazzaro et al., Nucl. Instr. and Methods A, 585 136 (2008).

[26] F. Pinna et al., J. Phys. Conf. Ser. 1056, 012046 (2018).

[27] F. Iazzi et al., WIT Transactions on Engineering Science 116, 206 (2017).

[28] H. Lenske et al., Phys. Rev. C 98, 044620 (2018).

[29] E. Santopinto et al., Phys. Rev. C 98, 061601(R) (2018).

[30] J. Bellone et al., J. Phys. Conf. Ser. 1056, 012004 (2018).

[31] S. Calabrese et al., Acta Phys. Pol. B 49, 275 (2018).
in Catania have shown that accurate cross sections measurements at very forward angles can be done. The main activity characterizing the NUMEN project is the measurement of DCE absolute cross sections, with the related processes, and the extraction of relevant NMEs. The NUMEN “Holy Graal” is to find a connection between the NMEs extracted from DCE reactions and those characterizing $0v\beta\beta$ decay. NUMEN is a big challenge both for nuclear technology and nuclear theory. Moreover it promotes an important upgrade of the experimental facilities and the development of the different theoretical aspects, connected with the nuclear structure and reaction mechanisms, involved in heavy ions induced in DCE reactions. High intensity beams are the new frontier for these challenging studies. NUMEN indicates a possible growth prospect of heavy-ion physics in synergy with neutrino physics, aims at giving an innovative contribution in one of the most promising fields of fundamental physics.

References

[1] J. D. Vergados et al., Reports on Progress in Physics 75, 106301 (2012).

[2] P. Vogel, Jour. of Phys. G 39, 124002 (2012).

[3] J. Barea, J. Kotila, F. Iachello, Phys. Rev. Lett. 109, 042501 (2012).

[4] S. Dell'Oro et al., Advances in High Energy Physics 2016, 216259 (2016).

[5] F. Cappuzzello et al., Eur. Phys. J. A 54, 72 (2018).

[6] C. Agodi et al., Nucl. Part. Phys. Proc. 265, 28 (2015).

[7] F. Cappuzzello et al., Eur. Phys. J. A 52, 167 (2015).

[8] F. Cappuzzello et al., Nature Communications 6, 6743 (2015).

[9] D. Carbone et al., Phys. Rev. C 95, 034603 (2017).

[10] J. R. B. Oliveira et al., J. Phys. G 40, 105101 (2013).

[11] M. Cavallaro et al., Phys. Rev. C 93, 064323 (2016).

[12] M. Cavallaro et al., Nucl. Instr. and Meth. A 700, 65 (2013).

[13] F. Cappuzzello et al., Eur. Phys. J. A 51, 145 (2015).

[14] L. Calabretta et al., Modern Physics Letters A 32, 17 (2017).

[15] M. Cortesi et al., Review of Scientific Instruments 88, 013303 (2017).

[16] D. Lo Presti et al., J. Phys. Conf. Ser. 18, 012034 (2018).

[17] S. Tudisco et al., Sensors 18, 2289 (2018).

[18] A. Muoio et al., EPJ Web of Conferences 117, 10006 (2016).

[19] D. Carbone et al., Results in Physics 6, 863-865 (2016).

[20] J. R. B. Oliveira et al., J. Phys. Conf. Ser. 18, 012040 (2018).

[21] C. Agodi et al., Nucl. Instr. and Meth. A 269 (3), 595-598 (1988).

[22] G. De Geronimo et al., IEEE Transactions on Nuclear Science, 60 2314-2321 (2013).

[23] D. Bonanno et al., J. Phys. Conf. Ser. 18 012006 (2018).

[24] A. Lazzaro et al., Nucl. Instr. and Methods A, 591 394 (2008).

[25] A. Lazzaro et al., Nucl. Instr. and Methods A, 585 136 (2008).

[26] F. Pinna et al., J. Phys. Conf. Ser. 1056, 012046 (2018).

[27] F. Iazzi et al., WIT Transactions on Engineering Science 116, 206 (2017).

[28] H. Lenske et al., Phys. Rev. C 98, 044620 (2018).

[29] E. Santopinto et al., Phys. Rev. C 98, 061601(R) (2018).

[30] J. Bellone et al., J. Phys. Conf. Ser. 1056, 012004 (2018).

[31] S. Calabrese et al., Acta Phys. Pol. B 49, 275 (2018).