Analysis of Light Neutrino Exchange and Short-Range Mechanisms in 0νββ Decay Frank F. Deppisch,1, ∗ Lukas Graf,2, y Francesco Iachello,3, z and Jenni Kotila4, 3, x 1Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK 2Max-Planck-Institut f¨urKernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany 3Center for Theoretical Physics, Sloane Physics Laboratory, Yale University, New Haven, Connecticut 06520-8120, USA 4Finnish Institute for Educational Research, University of Jyv¨askyl¨a,P.O. Box 35, FI-40014 Jyv¨askyl¨a,Finland Abstract Neutrinoless double beta decay (0νββ) is a crucial test for lepton number violation. Observa- tion of this process would have fundamental implications for neutrino physics, theories beyond the Standard Model and cosmology. Focussing on so called short-range operators of 0νββ and their potential interplay with the standard light Majorana neutrino exchange, we present the first complete calculation of the relevant nuclear matrix elements, performed within the interacting bo- son model (IBM-2). Furthermore, we calculate the relevant phase space factors using exact Dirac electron wavefunctions, taking into account the finite nuclear size and screening by the electron cloud. The obtained numerical results are presented together with up-to-date limits on the stan- dard mass mechanism and effective 0νββ short-range operators in the interacting boson model framework. Finally, we interpret the limits in the particle physics scenarios incorporating heavy arXiv:2009.10119v2 [hep-ph] 29 Nov 2020 sterile neutrinos, Left-Right symmetry and R-parity violating supersymmetry. ∗
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[email protected] x jenni.kotila@jyu.fi 1 I.