A Grounded Evidence-Retrieval Benchmark and Hybrid RAG Framework for Silicon Pixel Detector R&D

Abstract: The rapid growth of silicon pixel detector literature has made systematic evidence retrieval a practical bottleneck for detector R&D. LLMs alone are insufficient for this task, as specialised detector knowledge, long-tail technical details, and recent experimental results must be grounded in primary literature. We present the first evidence-grounded retrieval benchmark and a reproducible retrieval framework for silicon pixel detector studies, combining sparse lexical retrieval, dense semantic retrieval, hybrid retrieval, and graph-based literature exploration. The benchmark includes manually curated chunk-level evidence annotations, source-level diagnostics, semantic relevance checks, and negative-query abstention tests across two complementary detector-domain query sets. Systematic evaluation shows that hybrid sparse-dense retrieval provides the most reliable evidence recovery, while graph-based approaches are more effective for literature exploration than strict evidence ranking. These results highlight the importance of evidence-grounded retrieval for accessing long-tail detector knowledge and provide a practical foundation for retrieval-augmented tools supporting silicon detector research and high-energy physics instrumentation.