Name: 這種難以捉摸的粒子能否重塑標準模型？ (Could This Elusive Particle Reshape the Standard Model?)
Uploaded: 2021-09-22T18:25:24.000Z
Duration: 5 min 45 s

The standard model of particle physics,  with its quarks, leptons, and bosons,  

粒子物理學的標準模型，包括夸克、輕子和玻色子。

has served scientists incredibly well since it was  first put forward in 1967. For the most part, it  

自1967年首次提出以來，它為科學家提供了令人難以置信的服務。在大多數情況下，它

has correctly predicted the existence of particles  with such precision that it's often hailed as the  

準確地預測了粒子的存在，以至於它經常被譽為

most successful scientific theory of all time.  

有史以來最成功的科學理論。  

And yet scientists are not done with it, and they're 

然而，科學家們還沒有完成這項工作，他們正在

constantly probing around its edges hunting  for new particles. In fact several teams of  

不斷在其邊緣探測，尋找新的粒子。事實上，有幾個小組的

scientists are racing to discover what's known as  a Majorana fermion, which could be a major key to  

科學家們正在競相發現被稱為馬約拉納費米子的東西，它可能是解決這個問題的一個主要關鍵。

settling some of the universe's biggest mysteries.  

解決一些宇宙中最大的謎團。  

Fermions are matter particles like the quarks 

費米子是像夸克一樣的物質粒子

that make up protons and neutrons, as well as  electrons and neutrinos. Fermions also include  

組成質子和中子，以及電子和中微子。費米子還包括

corresponding antiparticles with very similar  properties except they have opposite charge, so  

相應的反粒子具有非常相似的特性，只是它們具有相反的電荷，所以

the antiparticle of a negatively charged electron  has a positive charge and is known as a positron.  

帶負電的電子的反粒子帶正電，被稱為正電子。  

Should a particle and its antiparticle meet,  the two will annihilate each other, leaving behind

如果一個粒子和它的反粒子相遇，兩者將相互湮滅，留下的是

only energy. But a Majorana fermion would  play by its own rules that could totally upend  

只有能量。但馬約拉納費米子會按照它自己的規則行事，這可能會完全顛覆

our understanding of the Standard Model. In theory  a Majorana particle doesn't have a corresponding  

我們對標準模型的理解。在理論上，一個馬約拉納粒子並沒有一個相應的

antiparticle; it is its own antiparticle! That  means when two of the same particles meet,  

反粒子；它是它自己的反粒子!這意味著當兩個相同的粒子相遇時。

they could wipe each other out. So where would we even begin to look  

他們可以互相消滅對方。是以，我們甚至可以從哪裡開始尋找

for a Majorana particle? As it happens  scientists have already identified a candidate  

為一個馬約拉納粒子？恰好科學家們已經確定了一個候選人

from the Standard Model; the neutrino. Neutrinos  are bizarre little things for more reasons than  

標準模型中的中微子。中微子是一種奇異的小東西，其原因不止是

just their famous ability to pass right through  whole planets. Unlike electrons and positrons  

只是它們著名的直接穿過整個行星的能力。與電子和正電子不同的是

which both can have right or left-handed  spins, neutrinos all have left-handed spins  

其中都可以有右手或左手的自旋，中微子都有左手的自旋

while antineutrinos are all right-handed.  To explain this, one idea is that maybe  

而反中微子都是右手的。  為了解釋這一點，一個想法是，也許

antineutrinos aren't antimatter after all, they're  just all the missing right-handed neutrinos. 

反中微子畢竟不是反物質，它們只是所有失蹤的右手中微子。

Speaking of missing matter, if neutrinos  are Majorana particles they could account  

談到缺失的物質，如果中微子是馬約拉納粒子，它們可以說明

for that too. One of the great mysteries of  the universe is why there's… well, anything. 

也是為了這個。宇宙的偉大奧祕之一是為什麼會有......嗯，任何東西。

There's no reason we can solidly point to that  explains why there's more matter than antimatter  

我們沒有任何理由可以確鑿地指出，可以解釋為什麼物質比反物質多。

today. There's nothing inherently special  about matter, and it probably formed in equal  

今天。物質本身並沒有什麼特別之處，它可能是在同等條件下形成的。

amounts with antimatter after the Big Bang. That means by now everything should have been  

宇宙大爆炸後的反物質數量。這意味著到現在一切都應該已經

annihilated, and yet here we are, made up  of and surrounded by regular matter, not  

湮滅了，但我們在這裡，由常規物質組成，並被常規物質所包圍，不是

getting spontaneously annihilated all the time.  It's possible the imbalance is the result of a  

一直在自發地被殲滅。  這種不平衡有可能是由於

particular way some atoms decay. Beta minus decay  is when a neutron in an unstable nucleus decays  

一些原子衰變的特殊方式。β-負衰變是指不穩定原子核中的一箇中子衰變

into a proton and emits an electron and  antineutrino. An extremely rare event  

變成一個質子，併發射出一個電子和反中微子。一個極其罕見的事件

known as double beta decay occurs when certain  nuclei have two neutrons decay simultaneously. 

當某些核有兩個中子同時衰變時，就會發生被稱為雙β衰變。

You see where I'm going with this right? If  a neutrino and an antineutrino are actually  

你知道我在說什麼了吧？如果一箇中微子和一個反中微子實際上是

the same particle capable of annihilating  itself, then sometimes double beta  

同一個粒子能夠自相殘殺，那麼有時雙β

decays will emit only electrons. This net gain of particles could help  

衰變將只釋放出電子。這種粒子的淨增益可以幫助

account for the imbalance between matter  and antimatter. Of course theorizing about  

解釋物質和反物質之間的不平衡。當然，在理論上對

Majorana particles is one thing, actually  finding evidence of them is quite another. 

馬約拉納粒子是一回事，實際找到它們的證據是另一回事。

While neutrinos are notoriously hard  to spot, neutrinoless double beta decay  

雖然中微子是出了名的難以發現，但無中微子的雙β衰變

should be detectable just by adding up the energy  of the resulting two electrons and isotope. 

僅僅通過將產生的兩個電子和同位素的能量相加就應該可以檢測到。

Really the problem lies with luck and timing.  Remember I said double beta decay is rare? Well  

真的，問題在於運氣和時機。  還記得我說過雙β衰變是罕見的嗎？那麼

a double beta decay where the neutrinos annihilate  each other should be at least 100 times rarer. 

中微子相互湮滅的雙β衰變應該至少稀少100倍。

That doesn't mean scientists  aren't still trying to spot it. 

這並不意味著科學家們沒有仍在努力發現它。

The preferred approach involves getting a huge  amount of an isotope capable of double beta decay  

首選的方法是獲得大量的能夠進行雙β衰變的同位素

and just… waiting. There are multiple experiments  active and planned using elements like germanium

而只是......等待。有多個正在進行和計劃進行的實驗，使用鍺等元素

and xenon. They need to keep background  radiation and the energetic movement of atoms  

和氙氣。他們需要保持背景輻射和原子的高能運動

from ruining the data so many of them are shielded  and kept cold, like the CUORE experiment in Italy  

為了防止破壞數據，許多數據被屏蔽並保持低溫，就像意大利的CUORE實驗一樣。

which is just 0.01 kelvin above absolute zero. What's cooler than that? Maybe the fact that  

這比絕對零度僅高出0.01開爾文。有什麼比這更冷的呢？也許是這樣的事實

it's protected by 4 metric tonnes of lead  recovered from a 2,000-year-old Roman shipwreck.  

它受到從2000年前的羅馬沉船上找到的4公噸鉛的保護。  

Seriously, the scientists borrowed it from a  museum. If these experiments don't see signs  

說真的，科學家們是從博物館借來的。如果這些實驗沒有看到跡象

of neutrinoless double beta decay, then  maybe it's even rarer than predicted, and  

的無中子雙β衰變，那麼也許它比預測的還要稀少，並且

even bigger tanks of decaying isotopes will be  necessary. Maybe it's not possible at all and  

更大的衰變同位素罐將是必要的。也許這根本不可能，而且

the Majorana particle is a dead-end. Or, if luck  is on our side, maybe we'll see the telltale sign  

馬約拉納粒子是一個死衚衕。或者，如果運氣在我們這邊，也許我們會看到提示信號

of two neutrinos erasing each other, and the  standard model and our understanding of the  

的兩個中微子相互擦除，以及標準模型和我們對其的理解。

universe will get a little bit more complete.  

Fun fact: Majorana Fermions are named for Ettore 

有趣的事實：馬約拉納費米子是以埃托里命名的

Majorana, a physicist who mysteriously disappeared  without a trace in 1938. So about that  

馬約拉納，一位在1938年神祕地消失得無影無蹤的物理學家。所以關於這一點

whole Standard Model being “The Most Successful  Scientific Theory of All Time”. Turns out a recent  

整個標準模型是 "有史以來最成功的科學理論"。事實證明，最近的一個

discovery has thrown a wrench in that. Amanda  has muon that here.

發現已經在這一點上拋出了一個扳手。阿曼達在這裡說過。

So, what major mysteries about our  universe do you want to see us cover next?

那麼，你希望看到我們接下來報道關於我們宇宙的哪些重大謎團？

Let us know down in the comments. Be sure to subscribe, and I'll see you

請在評論中告訴我們。請務必訂閱，我們會再見面的。