- 发帖可能变空内容，邪门暂不知所以然
- 『稷下学宫』新认证方式，24年网站打算和努力目标
主题：中微子超光速被证实是来源于误差 -- 领班军机
家园 中微子超光速被证实是来源于误差 去年九月份闹得沸沸扬扬的超光速中微子终于还是被证实没有超光速，误差来源于GPS接收机连接的坏光纤接头，这个可能导致了测量到的时间缩短。
BREAKING NEWS: Error Undoes Faster-Than-Light Neutrino ResultsIt appears that the faster-than-light neutrino results, announced last September by the OPERA collaboration in Italy, was due to a mistake after all. A bad connection between a GPS unit and a computer may be to blame.
Physicists had detected neutrinos travelling from the CERN laboratory in Geneva to the Gran Sasso laboratory near L'Aquila that appeared to make the trip in about 60 nanoseconds less than light speed. Many other physicists suspected that the result was due to some kind of error, given that it seems at odds with Einstein's special theory of relativity, which says nothing can travel faster than the speed of light. That theory has been vindicated by many experiments over the decades.
According to sources familiar with the experiment, the 60 nanoseconds discrepancy appears to come from a bad connection between a fiber optic cable that connects to the GPS receiver used to correct the timing of the neutrinos' flight and an electronic card in a computer. After tightening the connection and then measuring the time it takes data to travel the length of the fiber, researchers found that the data arrive 60 nanoseconds earlier than assumed. Since this time is subtracted from the overall time of flight, it appears to explain the early arrival of the neutrinos. New data, however, will be needed to confirm this hypothesis.
家园 按Physica Today的消息，他们还是有可能超光速 Physics Today: CERN issues statement about OPERA neutrino result
The first possible effect concerns an oscillator used to provide the time stamps for GPS synchronizations. It could have led to an overestimate of the neutrino's time of flight. The second concerns the optical fibre connector that brings the external GPS signal to the OPERA master clock, which may not have been functioning correctly when the measurements were taken.发现了两个可能的测量问题，第一个有可能让测量到的时间更长，这样中微子有可能飞的更快，第二个是光纤接头的问题，让测到的时间变短了。
看来Physics Today的编辑更乐观啊，还抱着一线希望能发现超光速，Science的新闻上面直接就忽略了第一个可能。
家园 Science前面那篇快报是内线消息 Science后来的长篇一点的报道也是沿用了新闻发布会上的说法，列举了两个误差。
我觉得两个误差八成是权威人士为了找回场子，让已经预约的验证实验至少可以继续的一个说法。
家园 这个可不是误差 是由于系统的故障。OPERA原来给出的系统误差极小，他们认为他们的测量的置信度（CL）有5个sigma（如果我没记错）。
实际上大部分物理学家都不太相信OPERA的超光速结果。因为之前的几个实验都证明了中微子没有超光速，虽然CL没有这么高。
此外，一个最让我信服的是之前观测超新星（SN 1987 A）爆发，中微子只早于光3个小时到达地球。而根据OPERA的数据，中微子应该早到4年左右。
（中微子早于光子到达一般认为是因为超新星的密度不足以束缚中微子，中微子能够比光子先逃逸）
从媒体的角度，他们是很希望中微子飞得更快的，中微子飞的越快，他们的点击率越高：）
通宝推：吴非,家园 汗，这个乌龙大了点。