#muons

Update: I've been banned from the physics department for the way I pronounce "Doppler effect."

Muons [Explained]

Transcript Under the Cut

Scientists were wrong about this “rule-breaking” particle

A famous particle physics mystery that once hinted at a hidden fifth force has now collapsed under the most precise calculations ever performed.

For decades, a puzzling discrepancy involving a tiny subatomic particle called the muon fueled speculation that physicists might be on the verge of discovering an entirely new force of nature. Now, an international research team led by a Penn State physicist says the mystery appears to have been solved, and the answer supports existing physics rather than overturning it. The researchers published their findings in the journal Nature, describing one of the most precise particle physics calculations ever completed. Their work shows that the long debated mismatch between theory and experiment was likely caused by limitations in earlier calculations rather than evidence of unknown physics.

A recent study offers proof of feasibility for using cosmic radiation detectors to discover underground spaces. The detectors identify muons—particles created when cosmic radiation collides with Earth's atmosphere, which penetrate the ground before losing their energy and coming to a stop. Thus, by detecting muons, archaeologists can map hidden voids such as tunnels and channels. The research team demonstrated the technology's effectiveness at the City of David archaeological site in Jerusalem, showing how the system successfully maps underground spaces based on changes in the soil's absorptivity to cosmic radiation particles.

If you have watched Marvel’s Ant-Man, I’m sure you are curious how the suit can manipulate space and matter to alter Ant-Man’s size. Also, I’m sure you’re curious to know if the physics behind it is even possible. Therefore, let us explore some of these concepts and implications.

Ant-Man’s suit uses theoretical “Pym” particles to shrink the space between matter, therefore adjusting the particles that make up his body. These Pym particles would have to carry a force that could change an electron to a muon, while keeping its electric charge constant. Leptons are currently categorized as the six subatomic particles that do not experience the strong force, including the electron. These particles vary in mass with the Muon being 200 times heavier than the Electron which is 0.5110 MeV/c^2. Therefore, the Pym particles could condense or expand a lot of “free space” by changing the  Leptons that make up his body. As he shrinks down smaller then a hydrogen atom, he reaches a size of less then 1.06*10^-35m, This means that the elementary particles occupying space have shrunk to the universal limit of 1.616255*10^-35m, known as Planck's constant. 

At this point, if Ant-Man were to get even smaller, he would be pushing space into another dimension. At the microscopic scale we experience reality in three dimensions, with the moment through time being our fourth. However, in the quantum world the universe behaves quiet differently and there is opportunity to interact with more dimensions. String theory predicts there to be ten or eleven dimensions, therefore making plenty of space for Ant-Man to manipulate his mass. Without these extra dimensions, Ant-Man would eventually meet a limit of how small he could go. 

From sticking a magnet on a fridge door to throwing a ball into a basketball hoop, the forces of physics are at play in every moment of our lives.

All of the forces we experience every day can be reduced to just four categories: gravity, electromagnetism, the strong force and the weak force.

Now, physicists say they have found possible signs of a fifth fundamental force of nature.

The findings come from research carried out at a laboratory near Chicago.

The four fundamental forces govern how all the objects and particles in the Universe interact with each other.

For example, gravity makes objects fall to the ground, and heavy objects behave as if they are glued to the floor.

The UK's Science and Technology Facilities Council (STFC) said the result "provides strong evidence for the existence of an undiscovered sub-atomic particle or new force".

So, hydrogen atoms usually repel one another, and the only way to get them to fuse is to increase the temperature and pressure like inside the core of a star. When they’re close enough, they may spontaneously fuse into helium. But, scientists have discovered a way of getting the helium atoms close enough under standard temperatures and pressures by using muons.

A muon is just a super heavy electron. By replacing the electron around a hydrogen atom with a muon, the atoms can get much much much closer together, making fusion possible at room temperature. Usually when a muon helps hydrogen atoms fuse, it gets ejected from the resultant helium atom and can attach itself to more hydrogen to facilitate even more fusion. It’s chain reaction, but the problem is that muons don’t last very long, and they lose a ton of energy and get stuck to the helium after a couple hundred fusions. It takes a lot of energy to create a muon, but each muon can only generate about half that energy in fusion, making it a net loss.

Generating muons on Earth is difficult, but we can detect muons bombarding the Earth from space! These can’t be used for fusion because there’s no way to collect them and channel them into a reactor, but the fact that we can detect them at all is an anomaly. The Earth’s atmosphere is so thick, and muons decay after so little time, that they shouldn’t ever be able to reach the ground and be detected. They should decay miles above the surface, but somehow we can detect them down here anyway.

It turns out that when muons travel at close to the speed of light, they experience time dilation, or distance contraction: space actually gets smaller for them, they can travel longer distances in the same amount of time, allowing them to pass through the atmosphere and hit our detectors before they decay.

If we could accelerate muons to close to the speed of light and bombard hydrogen with them, each muon would last longer and facilitate more fusions before getting stuck and decaying. But muons are heavy, so getting them going that fast would require even more energy, so I don’t know if the extra fusion would make up for it. I’m not a physicist, or a chemist, I don’t know things.

Scientists should at least try this. High-energy muons could crack cold fusion.