The NUMEN project @ LNS: Status and perspectives

F Cappuzzello,O Sgouros,S Brasolin,S Reito,Y Kucuk,J A Lay,A Foti,S Burrello,L Acosta,D Calvo,D Lo Presti,H Djapo,H Petrascu,P Ries,P Amador-Valenzuela,C Agodi,G Lanzalone,G De Geronimo,O Brunasso,I Ciraldo,P Mereu,V Capirossi,D R Mendes,S Tudisco,A Yildirin,V Werner,V Soukeras,A Pakou,D Torresi,V A B Zagatto,A Hacisalihoglu,I Boztosun,J S Wang,J Ma,P Finocchiaro,J Lubián ,M Cavallaro,M A G Silveira ,M Moralles,N H Medina,F Pinna,J R B Oliveira,L Serbina,F Iazzi,J Bellone,R.i.m Vsevolodovna ,Grazia D’agostino ,E Santopinto,L E Charon Garcia,A Spatafora,L Neri,G Russo,D Carbone,N Auerbach,Francesco La Via ,M Fisichella,N Deshmukh,C Altana,T Borello‐Lewin ,Y Y Yang,F Delaunay,R Chen,N Pietralla,D Bonanno,A Huerta-Hernandez,J Barea,K De Los Rìos ,G A Souliotis ,G A Brischetto ,L Pandola,Vincenzo Branchina ,H Lenske,S O Solakcı,R Bijker,L Calabretta,J L Ferreira,R Linares,J Ruíz ,M Colonna,G Gallo,H García-Tecocoatzi ,S Firat,A Russo ,M R D Rodrigues,Z J Kotila,R.b.b Santos ,D.j Marín-Lámbarri ,J Ferretti,E.r Chávez Lomelí ,L La Fauci,Carlo Ferraresi ,Salvatore Calabrese ,H Vargas Hernandez

doi:10.1063/1.5130964

Abstract

The NUMEN project aims at accessing experimentally driven information on Nuclear Matrix Elements (NME) involved in the half-life of the neutrinoless double beta decay (0νββ), by high-accuracy measurements of Heavy Ion (HI) induced Double Charge Exchange (DCE) reaction cross sections. In particular, the (18O,18Ne) and (20Ne,20O) reactions are used as tools for β+β+ and β−β− decays, respectively. In the experiments, performed at INFN - Laboratory Nazionali del Sud (LNS) in Catania, the beams are accelerated by the Superconducting Cyclotron (CS) and the reaction ejectiles are detected the MAGNEX magnetic spectrometer. The measured cross sections are challengingly low (a few nb), being the total reaction cross section much larger (a few b), thus a high sensitivity and a large rejection capability are demanded to the experimental set-up. This limits 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, still keeping the high sensitivity of the present set-up, making it feasible a systematic study of all the cases of interest. Frontiers technologies are going to be developed, to this purpose, for the accelerator and the detection systems. In parallel, advanced theoretical models are being developed in order to extract the nuclear structure information from the measured cross sections.

Highlights

The 0νββ decay of atomic nuclei is a long-searched phenomenon which, besides establishing the Majorana nature of neutrinos, has the potential to shed light on the absolute neutrino mass and hierarchy
NUMEN is fostering the development of a specific theory program to allow an accurate extraction of nuclear structure information from the measured cross sections
Relying on the use of the DWBA approximation for the cross section, the theory is focused on the development of microscopic models for Double Charge Exchange (DCE) reactions, employing several approaches (QRPA, shell model, IBM) for inputs connected to nuclear structure quantities

Summary

Introduction

The 0νββ decay of atomic nuclei is a long-searched phenomenon which, besides establishing the Majorana nature of neutrinos, has the potential to shed light on the absolute neutrino mass and hierarchy. NUMEN is fostering the development of a specific theory program to allow an accurate extraction of nuclear structure information from the measured cross sections. Relying on the use of the DWBA approximation for the cross section, the theory is focused on the development of microscopic models for DCE reactions, employing several approaches (QRPA, shell model, IBM) for inputs connected to nuclear structure quantities.

Results

Conclusion