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Physicists Just Solved a 35-Year-Old Mystery Hidden Inside Atomic Cores

posted by mrpg on Tuesday February 26 2019, @06:40AM   
from the when-a-core-is-a-core? dept.

upstart writes:

Submitted via IRC for SoyCow1984

Physicists Just Solved a 35-Year-Old Mystery Hidden Inside Atomic Cores

Here's a mysterious truth that scientists have known since 1983: Protons and neutrons act differently when they're inside an atom, versus floating freely through space. Specifically, the subatomic particles that make up those protons and neutrons, called quarks, slow down massively once they're confined to a nucleus in an atom.

Physicists really didn't like this, because neutrons are neutrons whether they're inside an atom or not. And protons are protons. Both protons and neutrons (which together make up the class of particles called "nucleons") are made up of three smaller particles, called quarks, bound together by the strong force.

"When you put quarks into a nucleus, they start to move slower, and that is very weird," said study co-author Or Hen, a physicist at the Massachusetts Institute of Technology. That's strange because the powerful interactions between quarks mainly determine their speed, whereas forces that bind the nucleus (and also act on quarks inside the nucleus) are supposed to be very weak, Hen added.

[...] Their data strongly suggest, Hen said, that the quarks in most nucleons don't change at all when they enter a nucleus. But those few involved in nucleon pairs change their behavior so dramatically that they skew the average results in any experiment. That many quarks packed into such a small space causes some dramatic strong force effects. The EMC effect is the result of just a minority of anomalies, rather than a change to the behavior of all protons and neutrons.

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Original Submission

• Re:Another one blaming minorities 'for science' (Score: 2) by DannyB on Tuesday February 26 2019, @03:57PM

  by DannyB (5839) on Tuesday February 26 2019, @03:57PM (#806988) Journal

  So in conclusion . . .

  Protons and neutrons act differently when they're inside an atom [ . . . ]
  the subatomic particles that make up those protons and neutrons, called quarks, slow down massively once they're confined to a nucleus

  So when you confine protons and neutrons into a small space together they don't really change, but they slow dance. They don't behave as fast and loose as when they're in their own peer groups outside of a nucleus. Especially those like-charged protons which tend to ordinarily repel unless they are a bit unusual.

  the quarks in most nucleons don't change at all when they enter a nucleus.

  Of course they don't change. Becoming involved in a nucleon pair also doesn't change anyone. Despite the wishes of some nucleons.

  But those few involved in nucleon pairs change their behavior so dramatically

  They change their behavior dramatically once involved in a nucleon pair, in order to remain in that nucleon pair. But they don't really change.

  because neutrons are neutrons whether they're inside an atom or not. And protons are protons.

  Protons will be protons. Neutrons will be neutrons.

  Physicists really didn't like this

  They need to get over it.

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