本帖最后由 zerowing 于 2015-11-6 10:48 編輯 ' B/ y3 g( D9 m! T# O: v
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恩，以后就以這個(gè)為標(biāo)題形成一個(gè)系列了。每周更新一次。感謝關(guān)注。
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Strong forces make antimatter stick
& n6 ?7 R& B8 k# `: W W# J3 I5 ?2 l強(qiáng)力致使反物質(zhì)結(jié)合
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Physicists have shed new light on one of the greatest mysteries in science: Why the Universe consists primarily of matter and not antimatter.; I+ o; } d! ~, L7 ]
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# L) P0 R9 l7 o/ u* X$ k8 d9 u* HAntimatter is a shadowy mirror image of the ordinary matter we are familiar with. 3 \+ K8 Y- X( H
0 l' n5 \5 Q( u$ h- _& iFor the first time, scientists have measured the forces that make certain antimatter particles stick together. ; f* R6 ?6 w8 g1 \, t! j
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The findings, published in Nature, may yield clues to what led to the scarcity of antimatter in the cosmos today.
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$ R# D5 \1 H D. K- @; a: D4 WThe forces between antimatter particles - in this case antiprotons - had not been measured before. If antiprotons were found to behave in a different way to their "mirror images" (the ordinary proton particles that are found in atoms) it might provide a potential explanation for what is known as "matter/antimatter asymmetry". 4 a! Z# G; ] j# x% a1 i
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At the beginning of the Universe, the Big Bang produced matter and antimatter in equal amounts. But that's not the world we see today: instead antimatter is extremely rare. * q) n' t! I7 R0 z' d
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Some phenomenon must have led to the overwhelming dominance of matter; scientists have their theories, but the evidence remains elusive. 1 C8 A# @8 |9 F1 k
* V1 \4 c0 x; V+ Q( \1 H, u"Although this puzzle has been known for decades and little clues have emerged, it remains one of the big challenges of science," said co-author Aihong Tang, from the Brookhaven National Laboratory in New York, US. + [! J w, Y$ ^) ?3 t4 x
7 A+ e( {2 K2 B; n2 U. W- z: g"Anything we learn about the nature of antimatter can potentially contribute to solving this puzzle."
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! P }$ {. H, ~! |& ^& O物理學(xué)家新近揭示科學(xué)界一大未解之謎：為什么宇宙主要由物質(zhì)組成，而非反物質(zhì)。7 C; g" n7 B' I$ n% V
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正如我們所熟悉的那樣，反物質(zhì)是物質(zhì)的一個(gè)陰暗鏡像（性質(zhì)相反，但卻難以看到）。
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( I9 p- F+ A! l) {& ^+ I; A _2 g9 Y而也是第一次，科學(xué)家們成功測(cè)量連接反物質(zhì)粒子間的結(jié)合力。
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這篇發(fā)表在 自然 網(wǎng)站上的研究，可能會(huì)解開導(dǎo)致反物質(zhì)在現(xiàn)在宇宙中稀缺的秘密。
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反物質(zhì)粒子之間的力，（例如此次的反質(zhì)子），以前從未有過(guò)測(cè)量。如果我們發(fā)現(xiàn)反質(zhì)子表現(xiàn)出同其“鏡像粒子（正常質(zhì)子微粒發(fā)現(xiàn)于原子中）“的不同運(yùn)行方式，則可為我們所知的”物質(zhì)、反物質(zhì)不對(duì)稱性“提供一個(gè)合理的解釋。
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# ^0 E) R- s7 ^, q6 D宇宙形成之初，”轟隆“一下（好吧，這是直譯，指奇點(diǎn)大爆炸）炸出等量的物質(zhì)和反物質(zhì)。而這跟我們今天的情況完全不同，我們的宇宙中幾乎找不到反物質(zhì)。) u+ R5 A% |; v& l
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因此，一定發(fā)生了一些會(huì)導(dǎo)致物質(zhì)以壓倒性優(yōu)勢(shì)顯現(xiàn)出來(lái)的現(xiàn)象。對(duì)此，科學(xué)家們各執(zhí)一詞，但卻一直無(wú)法證實(shí)。
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5 z* d# ^ |1 X8 I8 h. s”盡管這個(gè)難題已經(jīng)被認(rèn)知了幾十年，而且我們也發(fā)現(xiàn)了一些蛛絲馬跡，但他依舊是科學(xué)屆的一大挑戰(zhàn)！“合著者，來(lái)自美國(guó)紐約布魯克海文國(guó)家實(shí)驗(yàn)室的 愛紅﹒唐介紹說(shuō)，“任何一個(gè)我們發(fā)現(xiàn)到的關(guān)于反物質(zhì)的本質(zhì)都可能幫我們破解這個(gè)難題。”
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4 N5 J; x6 g$ m# E* VThankfully, antimatter can be produced by particle accelerators - albeit in tiny amounts - giving scientists the opportunity to study its properties. 1 x" V6 m* E; k% X1 l
Using a particle smasher called the Relativistic Heavy Ion Collider (RHIC) at Brookhaven, physicists were able to measured the force of interaction between pairs of antiprotons. 4 H, L8 e! l5 W. F2 v
The scientists found that the force between antiproton pairs is attractive, just like the strong nuclear force that holds protons together within atoms.
& g0 J: h" T' P, DAntimatter particles have the same masses as their ordinary matter equivalents, but carry opposite charges.
0 K9 y: z, T% y# CZhengqiao Zhang, another scientist who studied the antiproton interactions using the RHIC, said: "We see lots of protons, the basic building blocks of conventional atoms, coming out, and we see almost equal numbers of antiprotons.
* p, b6 }3 ? b8 s3 N) P& U2 X"The antiprotons look just like familiar protons, but because they are antimatter, they have a negative charge instead of positive, so they curve the opposite way in the magnetic field of the detector." Within the accuracy of these measurements, matter and antimatter appear to be perfectly symmetric. There didn't appear to be some asymmetric quirk of the strong force that could account for the continuing existence of matter in the Universe and the scarcity of antimatter. ; d, q& q* `* w; E4 F" @
That points scientists towards other explanations for the matter/antimatter asymmetry. For example, neutrinos (another fundamental building block of the Universe) might be their own antiparticles. Differences in the way neutrino particles interacted after the Big Bang might have led to a slight matter excess that allowed our Universe to exist.
h5 E- O$ q$ ]' M. @, Y8 h1 d/ x感謝上帝，我們可以通過(guò)粒子加速器產(chǎn)生反物質(zhì)——盡管只有微量，但這也提供了科學(xué)家們研究反物質(zhì)屬性的機(jī)會(huì)。
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通過(guò)使用布魯克海文國(guó)家實(shí)驗(yàn)室被稱為相對(duì)重離子碰撞機(jī)（RHIC）的粒子加速器，物理學(xué)家得以測(cè)定反質(zhì)子之間的作用力。
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科學(xué)家發(fā)現(xiàn)，反質(zhì)子之間具有很強(qiáng)的吸引力，就像原子核內(nèi)質(zhì)子間的強(qiáng)核力。
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反物質(zhì)粒子同正物質(zhì)具有相同的質(zhì)量，但是卻攜帶相反的電荷。2 S% r* L$ e: w! Z9 [
9 C0 {. _7 l6 b" d6 S2 G' C另一位在RHIC研究中的科學(xué)家——張正喬（估計(jì)是華裔）介紹說(shuō)：“我們看到的大量構(gòu)成基本原子的質(zhì)子飛出，而這個(gè)量與觀測(cè)到的反質(zhì)子幾乎相等。反質(zhì)子就像我們熟悉的質(zhì)子，但因?yàn)樗麄兪欠次镔|(zhì)，因此他們帶有一個(gè)單位的負(fù)電荷，而非正電荷。因此，他們?cè)诖艌?chǎng)檢測(cè)器重劃出相反的曲線。“2 \2 y) S! j+ g4 W7 v% _9 R
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基于這些測(cè)量的精確性，物質(zhì)和反物質(zhì)似乎是完全對(duì)稱的。沒有絲毫與正物質(zhì)性質(zhì)完全相悖的轉(zhuǎn)折性證據(jù)可以解釋為什么宇宙中存在連續(xù)物質(zhì)而鮮有反物質(zhì)。
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& z# D' j6 o. g4 B5 \( U4 c這說(shuō)明科學(xué)家只能寄希望于其他的可以解釋物質(zhì)、反物質(zhì)不對(duì)稱性的觀點(diǎn)。比如，中微子（另一種宇宙基本粒子）可能就是其本身的反物質(zhì)粒子。自”大爆炸“后中微子粒子間的不同相互作用方式可能導(dǎo)致我們的宇宙以一種微量不對(duì)稱的形式存在。
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! N/ \9 M- w9 T' N" K6 s' K7 p7 p點(diǎn)評(píng)：好吧。到最后，這幫孫子們也沒找到答案。只是更精確的又闡述了一遍反物質(zhì)。3 k+ Y3 ~1 U4 ?" P. @$ n6 h
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