Accueil du site > Actualités et Faits Marquants > A new leading contribution to neutrinoless double-beta decay
V. Cirigliano, W. Dekens, J. de Vries, M.L. Graesser, E. Mereghetti, S. Pastore, and U. van Kolck, Phys. Rev. Lett. 120 (2018) 202001
V. Cirigliano, W. Dekens, J. de Vries, M.L. Graesser, E. Mereghetti, S. Pastore, and U. van Kolck,
Phys. Rev. Lett. 120 (2018) 202001
One of the most important advancements in modern particle physics
was the observation of neutrino oscillations and the inference that
neutrinos have mass. However, the origin of neutrino masses remains a
mystery. They can arise from an interaction with the Higgs field that
violates lepton number, makes neutrinos Majorana particles, and
potentially explains the observed matter-antimatter asymmetry of the
universe. This mechanism is only accessible through neutrinoless
double-beta decay experiments, where two neutrons in a nucleus turn into
two protons, with the emission of two electrons and no neutrinos.
Nuclear physics is required for the interpretation of a non-zero signal
(or lack thereof) from the enormous experimental effort which is
underway around the world.
Based on renormalization arguments, we have now shown that the
leading contribution to neutrinoless double-beta decay, where light
Majorana neutrinos are exchanged between nucleons, is not well defined
without a short-range interaction. This short-range contribution is
missing in all current calculations and should eventually be determined
from simulations of Quantum Chromodynamics on a spacetime lattice. It
can also be estimated, via chiral symmetry, from isospin-breaking
observables in the two-nucleon sector. Using existing data for such an
estimate, we have shown explicitly in the decay of 12Be that this new
short-range contribution can be comparable to model-dependent estimates
of the long-range neutrino exchange. This new leading effect could thus
significantly affect the neutrino mass properties extracted from
double-beta-decay experiments.
Voir en ligne : Phys. Rev. Lett. 120 (2018) 202001
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