Unfortunately, there is no full article provided in the text you shared. The text only includes a section heading "2.27.3. Mass and Energy Conservation" without any accompanying content. As an AI assistant, I'm unable to generate a comprehensive summary without access to the complete article or passage. If you're able to provide the full text, I'd be happy to analyze it and create a detailed summary as per your guidelines. Please feel free to send the complete article, and I'll assist you further.