20.500.12556/RUL-180821 New avenues for $|\Delta B| = 2$ processes beyond neutron-antineutron oscillations We explore baryon-number-violating $(|\Delta B| = 2)$ processes beyond the well-known neutron-antineutron $(n -\overline{n})$ oscillations, focusing on the $\Lambda - \overline{\Lambda}$ system. The presence of a strange quark in the $\Lambda$ baryon introduces a new set of six-quark operators roughly of the form $(uds)^2$, which are different from the $(udd)^2$ operators responsible for $(n -\overline{n})$ oscillations. Using the Standard Model Effective Field Theory (SMEFT), we classify all dimension-9 operators that cause $|\Delta B| = 2$ transitions and study their UV completions mediated by exotic scalar fields with trilinear interactions. We demonstrate that in these models, $\Lambda - \overline{\Lambda}$ oscillations can occur at tree level, with $(n -\overline{n})$ mixing potentially appearing at higher loop levels. We employ a chiral effective theory to constrain the effective mass mixing $\delta m_{\Lambda}$ , deriving bounds from current experimental limits on $(n -\overline{n})$ scillations and dinucleon decays such as $pp \rightarrow K^+K^+$. These bounds indicate that $\Lambda - \overline{\Lambda}$ oscillations probe a complementary parameter space, sensitive to baryon-number violation at scales up to $10^2 - 10^3$ TeV. We show that the existing indirect bounds make it challenging to provide a competitive bound on $\delta m_{\Delta}$ at BESIII. physics of elementary particles beyond the Standard Model baryon number violation fizika osnovnih delcev fizika onkraj Standardnega modela kršitev barionskega števila true false true Angleški jezik Slovenski jezik Članek v reviji 2026-03-17 13:13:16 2026-03-17 13:13:17 2026-03-26 09:29:48 0000-00-00 00:00:00 2026 0 0 34 str. art. no. 124 Vol. 2026 Mar. 2026 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 539.120 1029-8479 10.1007/JHEP03(2026)124 271796995 JHEP03(2026)124.pdf JHEP03(2026)124.pdf 1 723B0445E2262133458517EC24F65713 2484ec64063bb7b1cf67ecfef3cf7b81edacd0d6d20bbb14a3720fba42231324 e3a098c5-21fa-11f1-b0ab-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=230687 https://link.springer.com/article/10.1007/JHEP03(2026)124 0 ecf9ba5d-21fa-11f1-b0ab-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=230688 Fakulteta za matematiko in fiziko 0 0 0