9 The Standard Model of Fundamental Particles
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again, and soon they were both laughing themselves silly.
“We should have brought the fly spray. They’re peskier than
mosquitoes.”
“They’re neutrinos,” said Dr Quantum. “So small that it’s hard
to know if they’re matter at all. And they have no electric
charge. That’s why they don’t hurt. They can even pass right
through the earth without affecting anything."
“Oh, my gosh,” cried Alice, squeezing her mother’s hand
tightly. With her free hand she pointed to a neutrino that
appeared to be undergoing some sort of change, turning into
a similar, but uglier, version of itself.
“Yes, there are three different types of neutrino, and they can
change from one to the other,” explained Dr Quantum.
“Why only three?” asked Alice. “Why not four, or five, or a
thousand?”
“Don’t ask so many …” began Marigold, before Dr Quantum
silenced her with a gesture.
“Three seems to be a very special number. There are also three
members of the family of leptons, three generations of quarks,
and three quarks make up a baryon."
“What’s he talking about, Mom?” Before Marigold could
think of a suitably evasive reply, Alice was tugging her arm and
pointing at a large spherical blob, surrounded by a shimmering
aura.
“I see you’ve found a hydrogen atom,” said Dr Quantum.
“Those are electrons buzzing about. Careful, don’t get too close
now.”
“That thing in the middle. I can see something moving inside
it. It’s pregnant.”
“It’s a proton, and those are quarks inside it.”
Alice began to giggle. “Cottage cheese. So, it ate too much
quark for dinner last night, did it?”
“No, those are a different type of quark, with funny names
like up and down, strange, charm, top and bottom. And there
are other little things in there as well, called gluons, because
they stick everything together.”
“Look, there’s another one, only a bit different. And over
there, a big group of them, both sorts. They’re having a party,
with that shimmery cloud stuff all around them.”
165
again, and soon they were both laughing themselves silly.
“We should have brought the fly spray. They’re peskier than
mosquitoes.”
“They’re neutrinos,” said Dr Quantum. “So small that it’s hard
to know if they’re matter at all. And they have no electric
charge. That’s why they don’t hurt. They can even pass right
through the earth without affecting anything."
“Oh, my gosh,” cried Alice, squeezing her mother’s hand
tightly. With her free hand she pointed to a neutrino that
appeared to be undergoing some sort of change, turning into
a similar, but uglier, version of itself.
“Yes, there are three different types of neutrino, and they can
change from one to the other,” explained Dr Quantum.
“Why only three?” asked Alice. “Why not four, or five, or a
thousand?”
“Don’t ask so many …” began Marigold, before Dr Quantum
silenced her with a gesture.
“Three seems to be a very special number. There are also three
members of the family of leptons, three generations of quarks,
and three quarks make up a baryon."
“What’s he talking about, Mom?” Before Marigold could
think of a suitably evasive reply, Alice was tugging her arm and
pointing at a large spherical blob, surrounded by a shimmering
aura.
“I see you’ve found a hydrogen atom,” said Dr Quantum.
“Those are electrons buzzing about. Careful, don’t get too close
now.”
“That thing in the middle. I can see something moving inside
it. It’s pregnant.”
“It’s a proton, and those are quarks inside it.”
Alice began to giggle. “Cottage cheese. So, it ate too much
quark for dinner last night, did it?”
“No, those are a different type of quark, with funny names
like up and down, strange, charm, top and bottom. And there
are other little things in there as well, called gluons, because
they stick everything together.”
“Look, there’s another one, only a bit different. And over
there, a big group of them, both sorts. They’re having a party,
with that shimmery cloud stuff all around them.”