https://doi.org/10.1140/epjc/s10052-021-09317-z
Regular Article - Experimental Physics
Search for double-beta decay of 
to the 
states of 
with CUORE
1
Department of Physics and Astronomy, University of South Carolina, 29208, Columbia, SC, USA
2
Department of Physics and Astronomy, University of California, 90095, Los Angeles, CA, USA
3
INFN–Laboratori Nazionali di Legnaro, 35020, Legnaro, Padua, Italy
4
INFN–Sezione di Bologna, 40127, Bologna, Italy
5
Dipartimento di Fisica, Sapienza Università di Roma, 00185, Rome, Italy
6
INFN–Sezione di Roma, 00185, Rome, Italy
7
INFN–Laboratori Nazionali del Gran Sasso, 67100, Assergi, L’Aquila, Italy
8
INFN–Sezione di Milano-Bicocca, 20126, Milan, Italy
9
Dipartimento di Fisica, Università di Milano-Bicocca, 20126, Milan, Italy
10
Center for Neutrino Physics, Virginia Polytechnic Institute and State University, 24061, Blacksburg, VA, USA
11
INFN–Sezione di Genova, 16146, Genoa, Italy
12
Dipartimento di Fisica, Università di Genova, 16146, Genoa, Italy
13
Massachusetts Institute of Technology, 02139, Cambridge, MA, USA
14
Key Laboratory of Nuclear Physics and Ion-beam Application (MOE), Institute of Modern Physics, Fudan University, 200433, Shanghai, China
15
Department of Physics, University of California, 94720, Berkeley, CA, USA
16
Nuclear Science Division, Lawrence Berkeley National Laboratory, 94720, Berkeley, CA, USA
17
INFN–Gran Sasso Science Institute, 67100, L’Aquila, Italy
18
Wright Laboratory, Department of Physics, Yale University, 06520, New Haven, CT, USA
19
INFN–Laboratori Nazionali di Frascati, 00044, Frascati, Rome, Italy
20
Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405, Orsay, France
21
Physics Department, California Polytechnic State University, 93407, San Luis Obispo, CA, USA
22
INPAC and School of Physics and Astronomy, Shanghai Laboratory for Particle Physics and Cosmology, Shanghai Jiao Tong University, 200240, Shanghai, China
23
Dipartimento di Fisica e Astronomia, Alma Mater Studiorum–Università di Bologna, 40127, Bologna, Italy
24
Service de Physique des Particules, CEA/Saclay, 91191, Gif-sur-Yvette, France
25
Lawrence Livermore National Laboratory, 94550, Livermore, CA, USA
26
Department of Nuclear Engineering, University of California, 94720, Berkeley, CA, USA
27
Dipartimento di Ingegneria Civile e Meccanica, Università degli Studi di Cassino e del Lazio Meridionale, 03043, Cassino, Italy
28
Department of Physics and Astronomy, The Johns Hopkins University, 3400 North Charles Street, 21211, Baltimore, MD, USA
29
INFN–Sezione di Padova, 35131, Padua, Italy
30
Engineering Division, Lawrence Berkeley National Laboratory, 94720, Berkeley, CA, USA
n
cuore-spokesperson@lngs.infn.it
Received:
27
January
2021
Accepted:
7
June
2021
Published online:
1
July
2021
The CUORE experiment is a large bolometric array searching for the lepton number violating neutrino-less double beta decay (
) in the isotope . In this work we present the latest results on two searches for the double beta decay (DBD) of to the first 
excited state of : the decay and the Standard Model-allowed two-neutrinos double beta decay (
). Both searches are based on a 372.5 kg
yr TeO
exposure. The de-excitation gamma rays emitted by the excited Xe nucleus in the final state yield a unique signature, which can be searched for with low background by studying coincident events in two or more bolometers. The closely packed arrangement of the CUORE crystals constitutes a significant advantage in this regard. The median limit setting sensitivities at 90% Credible Interval (C.I.) of the given searches were estimated as 
for the 
decay and 
for the 
decay. No significant evidence for either of the decay modes was observed and a Bayesian lower bound at 
C.I. on the decay half lives is obtained as: 
for the mode and 
for the mode. These represent the most stringent limits on the DBD of 
Te to excited states and improve by a factor 
the previous results on this process.
© The Author(s) 2021
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Funded by SCOAP3
