The Search For Nucleon Decay: Beyond The Standard Model Of Particle Physics

This book provides a comprehensive and up-to-date account of the experimental search for nucleon decay, a phenomenon that lies beyond the Standard Model of particle physics and probes the fundamental stability of matter. While free neutron decay is well understood, nucleons bound within nuclei are stable in the Standard Model due to baryon number conservation and kinematic constraints. The possible violation of this conservation law, however, is a key prediction of many theories beyond the Standard Model and has profound implications for particle physics and cosmology.The book focuses on the experimental challenges and methodologies involved in nucleon decay searches, with particular emphasis on large water Cherenkov detectors and atmospheric neutrino backgrounds. Drawing on more than three decades of direct involvement in the Super-Kamiokande experiment, the author presents firsthand insights into detector technology, data analysis strategies, and the interpretation of rare-event searches. The content builds upon invited review material prepared for the NNN23 workshop and incorporates developments from recent peer-reviewed publications, including results beyond those presented at the conference.Designed to be both accessible and authoritative, the book begins with concise introductions to the Standard Model, theories beyond it, and nucleon decay experiments, followed by detailed discussions and appendices that expand on technical derivations. It aims to serve graduate students, researchers, and experimentalists seeking a focused reference on nucleon decay and its role in the quest for new physics.