What is the muon decay experiment?

The muon decay is a radioactive process which follows the usual exponential law for the probability of survival for a given time t. Be sure that you understand the basis for this law. The goal of the experiment is to measure the muon lifetime which is roughly 2 µs.

What is Fermi coupling constant?

The coupling constant associated with the weak interaction (see fundamental interactions), which gives rise to beta decay. The Fermi constant has a value 1.435 × 10−36 joule metre3. The Fermi constant characterizes the Fermi theory of weak interactions.

How long does it take for a muon to decay?

about 2.2 μs
Muons have quite short lifetimes of about 2.2 μs at rest before they decay. However due to special relativity they have much longer lifetimes while travelling at high speeds. By slowing down these high speed muons, the muon decay constant at rest and the distribution of muon lifetimes was obtained.

Can a muon decay?

Muon decay Muons are unstable elementary particles and are heavier than electrons and neutrinos but lighter than all other matter particles. They decay via the weak interaction.

How does muon measure lifetime?

Muons are leptons from the second generation, with a unit electric charge and a mass much heavier than that of the electron: mμ = 105.7 MeV/c2. Their mean lifetime has been measured with great precision by combining data from several experiments to be τμ = 2.1969811(22) μs [1].

How does the muon experiment confirm the theory of relativity?

According to the special theory of relativity, if the muon is accelerated to a very high velocity, it should experience time dilation, which implies that its lifetime according to a stationary observer should increase.

What is Fermi theory of beta decay?

In particle physics, Fermi’s interaction (also the Fermi theory of beta decay or the Fermi four-fermion interaction) is an explanation of the beta decay, proposed by Enrico Fermi in 1933. The theory posits four fermions directly interacting with one another (at one vertex of the associated Feynman diagram).

What is Fermi repulsion?

As a mathematical consequence, fermions exhibit strong repulsion when their wave functions overlap, but bosons exhibit attraction. This repulsion is what the exchange interaction models. Fermi repulsion results in “stiffness” of fermions. That is why atomic matter, is “stiff” or “rigid” to touch.

How far does a muon travel in the laboratory on average before decaying?

Muons are created when cosmic rays traveling through space strike molecules in the atmosphere, some 10 kilometers above Earth’s surface. Even moving at nearly the speed of light, a muon should only be able to travel about 700 meters before it decays, so you might think no muons could ever reach Earth.

How was the muon discovered?

The muon was discovered when Anderson found particle tracks just like an electron but with Z/m 207 times smaller; the positron was discovered when Anderson found particle tracks just like an electron but curving in the wrong direction. Left: Carl Anderson working on his cloud chamber.

How do positive and negative muons decay and effect on lifetime?

The lifetime of positive muon does not change in the matter but the life time of negative muon decreases. (re-t/2.197 + e-t/T )+ B, Where r is the ratio of positive to negative muon and B is Background.

What is the half-life of a muon?

2.2 μs
Muons are unstable sub-atomic particles, and in simplest terms can be thought as being identical to electrons except that they have 206.7 times as much mass. They have a half-life of 1.56 μs (not to be confused with their mean lifetime of 2.2 μs).

How do you find the Fermi constant?

The most precise experimental determination of the Fermi constant comes from measurements of the muon lifetime, which is inversely proportional to the square of GF (when neglecting the muon mass against the mass of the W boson). In modern terms:

What is Fermi’s theory of decay?

Fermi’s Theory was the first theoretical effort in describing nuclear decay rates for β decay. The interaction could also explain muon decay via a coupling of a muon, electron-antineutrino, muon-neutrino and electron, with the same fundamental strength of the interaction.

How does the muon-neutrino interaction cause decay?

The interaction could also explain muon decay via a coupling of a muon, electron-antineutrino, muon-neutrino and electron, with the same fundamental strength of the interaction. This hypothesis was put forward by Gershtein and Zeldovich and is known as the Vector Current Conservation hypothesis.

Is the Fermi theory valid at energies higher than 100 GeV?

Since this cross section grows without bound, the theory is not valid at energies much higher than about 100 GeV. Here GF is the Fermi constant, which denotes the strength of the interaction.