Neutron-antineutron oscillation search using a 0.37 megaton-years exposure of Super-Kamiokande

Proton Decay in SUSY GUTs

“…It is pointed out that some SO (10) GUTs with the intermediate scale predict them, and that they may be linked to Majorana neutrino masses. The lower limit of lifetime for neutron bound in 16 O from the SuperKamiokande experiment gives the bound on the n-n oscillation as τ (n-n) > 4.7×10 8 sec [31]. It is better than the latest bound from the free neutron experiment τ (n-n) > 8.6 × 10 7 sec [32].…”

Progress and simulations for intranuclear neutron-antineutron transformations in Ar1840

“…Thus, in this model, there is a correlation between the radius and momentum of intranuclear nucleons, as the Fermi boundary energy is higher the larger the density of the nuclear medium, and so is local in character. In the MCSK, the Fermi motion is simulated via a nonlocal spectral function sourced directly from experimental measurements [23].…”

“…This paper is organized as follows: Sec. II will shortly summarize the main features of the latest model, and will highlight some of the main contrasts between this work and the model currently used within Super-Kamiokande [23]. In Sec.…”

Probing baryogenesis with neutron-antineutron oscillations

“…Therefore, to demonstrate the modelindependent implications of an observable rate of n-n oscillations for baryogenesis in the following section, we will take O 1 as a working example with the corresponding matrix element M 1 shown in figure 1. As a numerical example, considering the operator O 1 , we JHEP11(2021)185 take the Wilson coefficient to be C 1 (µ) ∼ Λ −5 1 , expressed in terms of a NP scale Λ 1 , such that for the most stringent current experimental limit from the Super-Kamiokande experiment [18] τ SK n-n ≥ 4.7 × 10 8 s, we obtain Λ 1 ≥ 7.04 × 10 5 GeV. For the NNBAR experiment with an expected improved future sensitivity by an order of magnitude τ NNBAR n-n ≥ 3 × 10 9 s we find the limit Λ 1 ≥ 1.02 × 10 6 GeV.…”

“…1 During the recent years, on the one hand, lattice-QCD calculations have been improved tremendously in computing the QCD matrix elements that connect amplitudes of B-violating interactions to n-n oscillations [17], on the other hand, the current experimental sensitivities and future prospects for the observation of n-n oscillations have improved significantly. Currently, the most stringent constraint from the bound n-n oscillation is due to the Super-Kamiokande experiment [18], which provides a limit on the n-n oscillation lifetime τ SK n-n ≥ 4.7 × 10 8 s. The current best limit from the free n-n oscillation is due to the ILL experiment [19] τ ILL n-n ≥ 0.86 × 10 8 s. Experimental sensitivities from both, free and bound n-n oscillation times, are expected to be improved significantly in future experiments. The DUNE experiment [20] is expected to achieve a sensitivity of τ DUNE n-n ≥ 7×10 8 s using 40 Ar nuclei, while NNBAR [21] will exploit the Large Beam Port of the ESS facility to search for free n-n oscillations and is expected to achieve an impressive sensitivity of JHEP11(2021)185 τ NNBAR n-n ≥ 3×10 9 s. Given the current stringent limits and expected future improvements in the experimental sensitivities for n-n oscillations, a detailed study of the phenomenological implications of such searches for baryogenesis mechanisms is timely and of high theoretical importance, since n-n oscillations are among very few observables which provide an opportunity to directly probe baryogenesis mechanisms and to distinguish underlying NP scenarios in synergy with direct searches at the high-energy frontier.…”