Direct generation of a Majorana mass for the neutron from exotic instantons

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• 作者：Andrea Addazi^a ; ^b ; ^{andrea.addazi@infn.lngs.it" class="auth_mail" title="E-mail the corresponding author}
• 刊名：Physics Letters B
• 出版年：2016
• 出版时间：10 June 2016
• 年：2016
• 卷：757
• 期：Complete
• 页码：462-467
• 全文大小：556 K

文摘

We discuss a new mechanism in which non-perturbative quantum gravity effects directly generate a Majorana mass for the neutron. In particular, in string theory, exotic instantons can generate an effective six quark operator by calculable mixed disk amplitudes. In a low string scale scenario, with M_S≃10÷10⁵ TeV$M_S\simeq 10÷{10}^5\text{TeV}$, a neutron–antineutron oscillation can be reached in the next generation of experiments. We argue that protons and neutralinos are not destabilized and that dangerous FCNCs are not generated. We show an example of quiver theories, locally free by tadpoles and anomalies, reproducing MSSM plus a Majorana neutron and a Majorana neutrino. These models naturally provide a viable baryogenesis mechanism by resonant RH neutrino decays, as well as a stable WIMP-like dark matter.