图①：江门中微子实验探测器。 刘悦湘摄（新华社发） 图②：江门中微子实验探测到的一个反应堆中微子事例示意图。 JUNO 合作组供图（新华社发） 图③：工作人员在纯水间监测超纯水处理情况。 新华社记者 金立旺摄 刘悦湘摄（新华社发） 网友：我关注到中国科学院高能物理研究所刚发布的一则消息：江门中微子实验装置正式建设成功，同 时发布首个物理成果。中微子到底是什么？探索中微子很重要吗？ 编辑：江门中微子实验（JUNO）是我国新一代中微子实验装置，是探索"幽灵粒子"——中微子的关键 设施，有助于解释宇宙演化的奥秘。本期"院士讲科普"，我们邀请中国科学院院士、江门中微子实验项 目经理王贻芳，为我们揭示这项大国重器背后的科学密码。 11月19日，中国科学院高能物理研究所副所长、江门中微子实验合作组物理分析负责人温良剑报告了江 门中微子实验的首个物理成果。通过对59天有效数据的分析，江门中微子实验合作组测量了被称为"太 阳中微子振荡参数"的混合角θ12及其相关的质量参数，比此前实验的最高精度提高了1.5到1.8倍。 据介绍，这两个振荡参数最初是通过太阳中微子所测定，但也可以通过反应堆中微子精确测定。此前这 两种方法对质量平 ...

Core Insights - The Jiangmen Underground Neutrino Observatory (JUNO) has successfully completed its construction and released its first physical results, achieving a measurement precision of 1.5 to 1.8 times better than previous best results for two key solar neutrino oscillation parameters [1][5] Group 1: Scientific Objectives - JUNO aims to determine the mass ordering of three types of neutrinos: electron neutrinos, muon neutrinos, and tau neutrinos, which is a fundamental question in neutrino physics [2] - The observatory will also conduct precise measurements of neutrino oscillation parameters and cross-research on solar neutrinos, terrestrial neutrinos, supernova neutrinos, atmospheric neutrinos, and proton decay [2] Group 2: Significance for Humanity - Neutrinos are linked to the origins of the universe and play a crucial role in the formation of galaxies and life, as their slight mass allows for the preservation of density fluctuations from the early universe [3] - The exploration of neutrinos represents a pure pursuit of natural laws, with potential long-term implications that are currently unpredictable, similar to the early discoveries of electricity [3] Group 3: Importance of Precision Measurement - Accurate measurement of neutrino oscillation parameters is essential for addressing unresolved questions in physics, such as whether neutrinos are their own antiparticles, which impacts our understanding of existence in the universe [4] - The recent results from JUNO highlight the importance of high-precision measurements to clarify discrepancies in previous data, which could indicate new physics beyond the standard model [5]

Core Insights - The Jiangmen Underground Neutrino Observatory (JUNO) has successfully completed its construction and released its first physical results, achieving a measurement precision of 1.5 to 1.8 times better than previous best results for two key solar neutrino oscillation parameters [2][3] Group 1: Scientific Objectives - JUNO aims to determine the mass ordering of three types of neutrinos: electron neutrinos, muon neutrinos, and tau neutrinos, which is a fundamental question in neutrino physics [3] - The observatory will also conduct precise measurements of neutrino oscillation parameters and cross-research on solar neutrinos, terrestrial neutrinos, supernova neutrinos, atmospheric neutrinos, and proton decay [3] Group 2: Significance for Humanity - Neutrinos are linked to the origins of the universe and play a crucial role in determining the conditions necessary for the existence of matter [4][5] - The study of neutrinos is a pure exploration of natural laws, with potential long-term value that is currently unpredictable, similar to the early days of electricity [5] Group 3: Importance of Precision Measurement - Accurate measurements of neutrino oscillation parameters are essential for addressing fundamental mysteries in physics, such as whether neutrinos are their own antiparticles [6] - The recent results from JUNO significantly improve the measurement precision of solar neutrino oscillation parameters, which may clarify discrepancies in previous measurements and could indicate new physics [6]

Core Insights - The Jiangmen Underground Neutrino Observatory (JUNO) has successfully completed its construction and announced its first scientific results, measuring solar neutrino oscillation parameters with an accuracy improved by 1.5 to 1.8 times compared to previous experiments [1][4][6]. Group 1: Project Overview - JUNO is the first large-scale, high-precision neutrino experiment of its kind, designed to detect elusive neutrinos, often referred to as "ghost particles" [1][3]. - The project is a significant international collaboration involving over 700 researchers from 75 institutions across 17 countries and regions [8][11]. - The observatory is set to officially begin data collection on August 26, 2025, after a series of construction and installation phases that began in 2008 [11]. Group 2: Scientific Achievements - The first physical results from JUNO were derived from data collected over 59 days, confirming the solar neutrino oscillation parameters and addressing the previously noted "solar neutrino anomaly" [6][9]. - The experiment's design allows for simultaneous measurement of both solar and reactor neutrinos, which could provide insights into new physics beyond the current particle physics framework [6][11]. - The core detector, with an effective mass of 20,000 tons, is designed to achieve unprecedented sensitivity in neutrino detection, focusing on neutrino mass ordering and oscillation parameters [11]. Group 3: Future Prospects - JUNO is expected to produce significant scientific results over the next few decades and contribute to the training of a new generation of physicists [11]. - The facility has a design lifespan of 30 years and can be upgraded to become the world's most sensitive experiment for neutrinoless double beta decay, potentially probing the absolute mass of neutrinos [11].

Core Insights - The Jiangmen Underground Neutrino Observatory (JUNO) has successfully completed its construction and released its first physical results, achieving a measurement precision of 1.5 to 1.8 times better than previous best results for two key solar neutrino oscillation parameters [1][2] Group 1: Scientific Significance of Neutrinos - Neutrinos, known as "ghost particles," can easily penetrate matter and carry ancient information about the universe's birth and evolution [2] - JUNO aims to determine the mass hierarchy of three types of neutrinos: electron neutrinos, muon neutrinos, and tau neutrinos, which is a fundamental question in neutrino physics [2] - The observatory will also conduct precise measurements of neutrino oscillation parameters and cross-research on solar, terrestrial, supernova, atmospheric neutrinos, and proton decay [2] Group 2: Implications for Humanity - The study of neutrinos is linked to the origins of the universe and the conditions necessary for the existence of matter, as their mass influences the formation of galaxies and stars [3] - Understanding neutrinos is a pure exploration of natural laws, with potential long-term benefits that are currently unpredictable, similar to the early discoveries of electricity [3] Group 3: Importance of Precision in Measurements - Accurate measurements of neutrino oscillation parameters are crucial for addressing unresolved questions in physics, such as whether neutrinos are their own antiparticles [4] - Inaccurate measurements could lead to significant resource investments in new experiments over many years, while precise measurements could clarify many ambiguous physical concepts [5] - The recent results from JUNO highlight the importance of high-precision measurements in resolving discrepancies in neutrino oscillation parameters, which may indicate new physics beyond the standard model [5]

Core Insights - The Jiangmen Underground Neutrino Observatory (JUNO) has successfully completed its construction and released its first physical results, marking a significant milestone in neutrino research [1][2]. Group 1: Neutrino Research Significance - Neutrinos are one of the three types of fundamental particles that make up the material world, and they are produced in vast quantities by processes such as nuclear reactions in stars and radioactive decay [2]. - The JUNO experiment aims to address a major question in particle physics: the ordering of neutrino masses, which is crucial for understanding the fundamental properties of these particles [2][3]. Group 2: Experimental Achievements - The JUNO collaboration reported a measurement of the solar neutrino oscillation parameters with unprecedented precision, improving upon previous experiments by 1.5 to 1.8 times [3]. - The experiment confirmed a previously observed discrepancy known as the "solar neutrino anomaly," which suggests the possibility of new physics beyond the standard model [3]. Group 3: Future Prospects - The JUNO facility is expected to produce significant physical results over the coming decades and contribute to the training of a new generation of physicists [4]. - With a design lifespan of 30 years, JUNO can be upgraded to become the world's most sensitive experiment for detecting neutrinoless double beta decay, which could provide insights into whether neutrinos are their own antiparticles and help measure their absolute mass [3].

Core Insights - The Jiangmen Neutrino Experiment (JUNO) has officially begun data collection as of August 26, 2023, aiming to address significant questions in particle physics, particularly the mass ordering of neutrinos [1][2] - This facility, constructed over more than a decade, is designed to provide high-precision measurements of neutrino oscillation parameters and explore various astrophysical phenomena [1][2] Group 1 - The experiment is located 700 meters underground in Jiangmen, Guangdong, featuring a large organic glass sphere with a diameter exceeding 35 meters, which captures neutrinos [1] - Neutrinos are fundamental particles that constitute the material world and are the most abundant particles in the universe, yet many mysteries surrounding them remain unsolved [1][2] - The core detector of the experiment contains 20,000 tons of liquid scintillator, with thousands of photomultiplier tubes embedded in its outer wall to detect weak light signals generated by neutrino interactions [1][2] Group 2 - The project team successfully filled over 60,000 tons of ultra-pure water within 45 days, ensuring the liquid level difference between the inner and outer spheres is controlled to a centimeter level, with a flow deviation of no more than 0.5% [2] - The experiment is a collaboration involving approximately 700 researchers from 17 countries and regions, marking the first operation of such a large-scale and high-precision neutrino-specific scientific facility internationally [2] - The design lifespan of the Jiangmen Neutrino Experiment is planned for 30 years, with potential upgrades to conduct double beta decay experiments to investigate the absolute mass of neutrinos and whether they are Majorana particles [2]

Core Insights - The Jiangmen Neutrino Experiment (JUNO) has officially commenced data collection as of August 26, 2023, aiming to address significant questions in particle physics, particularly the mass ordering of neutrinos [1][2] - This facility, constructed over more than a decade, represents a major advancement in neutrino research, building on previous experiments like the Daya Bay Neutrino Experiment [1][2] Group 1: Project Overview - The JUNO facility is located 700 meters underground in Jiangmen, Guangdong, featuring a large acrylic sphere with a diameter exceeding 35 meters designed to detect neutrinos [1] - The experiment will not only focus on neutrino mass ordering but also measure neutrino oscillation parameters with higher precision and explore various astrophysical phenomena [1][2] Group 2: Technical Achievements - The project team successfully filled over 60,000 tons of ultra-pure water within 45 days, maintaining a liquid level difference within centimeters and a flow deviation of less than 0.5%, ensuring the stability and safety of the detector [2] - This experiment is the first of its kind to operate a large-scale, high-precision neutrino detection facility internationally, providing insights into fundamental questions about matter and the universe [2] Group 3: Future Prospects - The JUNO facility is designed for a lifespan of 30 years, with potential upgrades to conduct double beta decay experiments to investigate the absolute mass of neutrinos and test if they are Majorana particles [2] - The collaboration involves approximately 700 researchers from 17 countries and regions, marking a significant international effort in advancing neutrino physics [2]

Core Insights - The Jiangmen Underground Neutrino Observatory (JUNO) has successfully completed the infusion of 20,000 tons of liquid scintillator and has officially begun data collection, marking a historic milestone in neutrino research [1][2] - JUNO is the first large-scale, high-precision neutrino detector in the world, aimed at addressing fundamental questions about the nature of matter and the universe [1][2] - The detector is located 700 meters underground in Jiangmen, Guangdong Province, and can detect neutrinos from nuclear power plants located 53 kilometers away, measuring their energy spectrum with unprecedented precision [1][2] Technical Details - JUNO's design allows for the measurement of neutrino mass ordering without being affected by terrestrial matter effects and other unknown neutrino oscillation parameters, significantly improving the precision of three out of six neutrino oscillation parameters [2] - The core of the JUNO detector consists of a 20,000-ton liquid scintillator housed in an organic glass sphere, surrounded by thousands of photomultiplier tubes that detect faint light signals produced when neutrinos interact [2] - The construction of JUNO involved extensive planning, testing, and collaboration among hundreds of engineers and technicians, ensuring strict requirements for material purity, stability, and safety [2] Collaborative Efforts - JUNO is a major international collaboration led by the Institute of High Energy Physics of the Chinese Academy of Sciences, involving approximately 700 researchers from 74 institutions across 17 countries and regions [3] - The success of JUNO is attributed to effective international cooperation, which brought expertise in liquid scintillator detection technology to the project, pushing the boundaries of this technology [3] - The design lifespan of JUNO is planned for 30 years, with potential upgrades to become the world's most sensitive experiment for neutrinoless double beta decay, aiming to measure the absolute mass of neutrinos and investigate whether neutrinos are Majorana particles [3]

Core Insights - The Jiangmen Underground Neutrino Observatory (JUNO) has successfully completed the infusion of 20,000 tons of liquid scintillator and has officially begun data collection, marking it as the first operational large-scale and high-precision neutrino-specific scientific facility in the world [1][9] - The initial data collected during the trial operation indicates that the key performance indicators of the JUNO detector have met or exceeded design expectations, enabling it to address a significant issue in particle physics: the ordering of neutrino masses [1][9] Group 1 - The JUNO detector is located 700 meters underground near Jiangmen, Guangdong Province, and can detect neutrinos produced by the Taishan and Yangjiang nuclear power plants, measuring their energy spectrum with unprecedented precision [2] - Unlike similar international experiments, JUNO's measurement of mass ordering is unaffected by terrestrial material effects and other unknown neutrino oscillation parameters, significantly improving the precision of three out of six neutrino oscillation parameters [2] Group 2 - The JUNO project was proposed by the Institute of High Energy Physics, Chinese Academy of Sciences in 2008, received strategic support in 2013, and began construction of the underground laboratory in 2015 [5] - The laboratory construction was completed in December 2021, and the detector installation began, with the infusion of ultra-pure water and liquid scintillator starting in December 2024 [5] - The project team successfully infused over 60,000 tons of ultra-pure water within 45 days, maintaining a liquid level difference within centimeters and a flow deviation of no more than 0.5%, ensuring the safety and stability of the detector structure [5] Group 3 - The core detector of JUNO has an effective mass of 20,000 tons and is located in a 44-meter deep water pool, featuring a stainless steel mesh shell that supports various critical components, including a 35.4-meter diameter acrylic sphere and numerous photomultiplier tubes [7] - The JUNO project is a major international collaboration led by the Institute of High Energy Physics, involving nearly 700 researchers from 74 institutions across 17 countries and regions [9] - The design lifespan of JUNO is 30 years, with potential upgrades to become the world's most sensitive experiment for neutrinoless double beta decay, which could provide insights into fundamental questions about the nature of matter and the universe [9]