比光速還快的粒子略過愛因斯坦？
Will faster-than-light particles bypass Einstein? Lightspeed particles 'may break laws of physics'.
By Marlowe Hood (AFP) – 2011.09.23
法新社巴黎電 -- 物理學家週四報告，稱為「微中子（neutrinos）」的次原子粒子，其傳播比光還快，這項發現 -- 如經證實 -- 將在愛因斯坦的相對論中轟出一個洞。
PARIS — Physicists reported Thursday that sub-atomic particles called neutrinos can travel faster than light, a finding that -- if verified -- would blast a hole in Einstein's theory of relativity.
研究者表示，在瑞士 CERN 與義大利一家實驗室之間進行的實驗裡，這些微小粒子被紀錄到的速度為每秒 300,006 公里，約比光速快 6 公里／秒。
In experiments conducted between the European Centre for Nuclear Research (CERN) in Switzerland and a laboratory in Italy, the tiny particles were clocked at 300,006 kilometres per second, about six km/sec faster that the speed of light, the researchers said.
"這結果令人大為驚訝，" 物理學家 Antonio Ereditato 表示，該實驗（稱為 OPERA）的發言人。"我們想要測量微中子的速度，但我們並沒有預期會發現任何特別的東西。"
"This result comes as a complete surprise," said physicist Antonio Ereditato, spokesman for the experiment, known as OPERA. "We wanted to measure the speed of neutrinos, but we didn't expect to find anything special."
他說，科學家公開宣佈之前，花了將近六個月的時間 "檢查、測試、控制並重新檢查每樣東西。"
Scientists spent nearly six months "checking, testing, controlling and rechecking everything" before making an announcement, he said.
涉及此實驗的研究者在描述其衝擊時格外小心，並呼籲世界各地的物理學家仔細檢查他們的資料，那預計過夜後就會上線。
Researchers involved in the experiments were cautious in describing its implications, and called on physicists around the world to scrutinise their data, to be made available online overnight.
但這些發現，他們表示，可能重塑我們對於物理世界的理解。
But the findings, they said, could potentially reshape our understanding of the physical world.
"如果此測量經證實，那也許會改變我們對於物理的看法，" CERN 研究主任 Sergio Bertolucci，這是幾位由法新社所接觸的獨立物理學家反應出來的一種觀點。
"If this measurement is confirmed, it might change our view of physics," said CERN research director Sergio Bertolucci, a view echoed by several independent physicist contacted by AFP.
在實驗中，科學家從 CERN（那橫跨法瑞邊境，靠近日內瓦）射出一道製造出無數微中子的射束到 730 公里外位於義大利的 Gran Sasso 實驗室。
In the experiments, scientists blasted a beam producing billions upon billions of neutrinos from CERN, which straddles the French-Swiss border near Geneva, to the Gran Sasso Laboratory 730 kilometres (453 miles) away in Italy.
微中子為電中性粒子，那如此之渺小以至於直到最近它們才被發現具有質量。
Neutrinos are electrically neutral particles so small that only recently were they found to have mass.
數量超多但難以偵測，這些「鬼魅粒子」為恆星（例如太陽）核融合反應的副產品之一。
Hugely abundant but hard to detect, these "ghost particles" are a by-product of nuclear fusion from stars, such as the Sun.
"這些微中子抵達的時間比光速所花的 2.3 毫秒（milliseconds）還要早 60 奈秒，" Ereditato 向法新社表示，並補充表示，誤差幅度（margin of error，原文錯了）小於 10 奈秒。
"The neutrinos arrived 60 nanoseconds earlier that the 2.3 milliseconds taken by light," Ereditato told AFP, adding that the margin or error was less than 10 nanoseconds.
然而，在亞伯特愛因斯坦的狹義相對論中，一個物理物體（physical object）在真空中的傳播無法比光的速度還快。
Under Albert Einstein's theory of special relativity, however, a physical object cannot travel faster than the speed of light in a vacuum.
微中子能移動通過物質這個事實 -- 包括一部分地殼 -- 無法導致它們加速，法國物理學家 Pierre Binetruy 表示，他並沒有涉入該實驗，但複審過資料。
The fact that the neutrinos were moving through matter -- including a slice of Earth's crust -- could not have caused them to accelerate, said French physicist Pierre Binetruy, who was not involved in the experiment but has reviewed the data.
"那可能使它們變慢，但那毫無疑問無法使它們跑得比光速還快，" 他週四晚上在巴黎向記者表示。
"It might have slowed them down, but it certainly didn't make them go faster than the speed of light," he told journalists in Paris on Thursday night.
Binetruy 將此結果描述成："全然地革命性，" 並表示它們將（如獲支持）迫使物理學家走回黑板。
Binetruy described the results "altogether revolutionary," and said they will, if backed up, force physicists to go back to the blackboard.
"The theory of general relativity, the theory of special relativity -- both are called into question," he said.
Alfons Weber（一位微中子專家，他在 2007 年於美國 Fermilab 參與過類似實驗）同意，比光還快的微中子無法與目前的理論一致，但他表示，這些結果需要在其他地方被複製。
Alfons Weber, a neutrino expert who participated in a similar experiment in 2007 at the US Fermilab, agreed that the faster-than-light neutrinos could not be reconciled with current theories, but said the results needed to be duplicated elsewhere.
"這裡仍有測量誤差（measurement error）的可能性，" 他透過電話表示。"如果為真，那真的太令人振奮了。這也是我為何要小心謹慎的緣故。"
"There is still the possibility of a measurement error," he said by phone. "It would be too exciting to be true. That's why I'm cautious."
先前與光競速的測試，在相同距離下進行，也讓微中子略佔優勢，但這些結果在實驗的誤差幅度內，Weber 說，牛津大學一位粒子物理學教授。
The earlier test, conducted over the same distance, also gave a slight edge to neutrinos in the race against light, but the results were within the experiment's margin of error, said Weber, a professor of particle physics at Oxford University.
他補充道，CERN 宣佈，很有可能在美國推動另一輪更加精確的測試。
The CERN announcement was likely to prompt another round of more accurate tests in the US, he added.
然而，即便經過驗證，這些新發現也無法完全廢止愛因斯坦耀眼的洞見，那已支配超過一世紀。
Even if verified, however, the new findings would not entirely invalidate Einstein's brilliant insights, which have held sway for more than a century.
"如果你將狹義相對論應用在有效之處，那仍將是個好理論，不過這將會有某些延伸或修改，" 他說。
"The theory of special relativity will still be a good theory if you apply it where it is valid, but there will have to be some extensions or modifications," he said.
他提到，即便愛因斯坦的理論經證實並非相當正確，牛頓的重力理論仍可完善解釋星球的運動，足以將任務送入太空。
Newton's theory of gravity, he noted, still explains the movement of planets well enough to send missions into space, even if Einstein's theories proved that it was not quite correct.
對於微中子出乎意料之外的快速，理論物理學家必然會開始尋找新的解釋。
Theoretical physicists are sure to begin searching for new explanations to account for the unsuspected quickness of neutrinos.
Binetruy 大膽表示，事情很可能是這樣︰"粒子很可能在其他維度（除了我們所知的四個維度 -- 空間的三個維度，加上時間維度 -- 之外的維度）發現了捷徑。"
It could be that "the particles have found a shortcut in another dimension" besides the four -- three in space, plus time -- we know about, Binetruy ventured.
"也有可能只意味著，光的速度並非我們所以為的速度極限。"
"Or it could simply mean that the speed of light is not the speed limit we thought it was."
By Marlowe Hood (AFP)
Copyright © 2011 AFP. All rights reserved.
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