Antimuon
Composition :
Statistics :
Generation :
Family :
Interaction forces :
Symbol :
Antiparticle :
Mass :
Decays into :
Electric charge :
Color charge
Spin :
Weak isospin :
Elementary antiparticle
Fermionic
Second
Lepton
weak,
electromagnetic force
gravity
μ⁺
Muon ( μ )
105.6583755(23) MeV/c²
electron (e⁻)
electron antineutrino ( νₑ )
muon neutrino (νμ)
1 e
none
¹/₂
LH : - ¹/₂, RH : 0
_
ANTIMUON
Definition
An antimuon is an elementary particle that belongs to the lepton family, just like electrons and neutrinos. It is the antiparticle counterpart of the muon, and together they form a second generation lepton pair. Muons and antimuons share many similarities with electrons and positrons, respectively, as they are both charged particles with opposite electric charges.
Here are some key characteristics of antimuons:
Charge: Antimuons have a positive electric charge, which is equal in magnitude but opposite in sign to the negative charge of regular muons. The charge of an antimuon is approximately +1 elementary charge (e).
Mass: The antimuon has a mass of about 105.66 MeV/c² (mega-electronvolts per speed of light squared), which is roughly 207 times the mass of an electron. However, it is still much lighter than protons and neutrons.
Spin: Like all leptons, antimuons have a half-integer spin of 1/2 ħ (h-bar), where ħ is the reduced Planck constant. This spin value is a fundamental property associated with quantum angular momentum.
Lifespan: Antimuons are unstable particles with a relatively short mean lifetime. They decay via the weak interaction, specifically through processes involving the exchange of W and Z bosons. The mean lifetime of a free antimuon is approximately 2.2 microseconds.
Interaction with Matter: Antimuons, like muons, interact primarily through the weak force and gravity. They are also subject to electromagnetic interactions due to their positive charge, but the strength of these interactions is considerably weaker than those experienced by charged particles like electrons.
Creation and Detection: Antimuons can be created in high-energy processes, such as certain particle collisions. They can also be produced naturally in cosmic ray interactions with the Earth's atmosphere. Detection of antimuons typically involves sophisticated particle detectors capable of identifying their tracks and energy deposits.
Role in Particle Physics: Antimuons, along with muons, are essential in studying the properties of the weak force and flavor-changing processes in particle physics. They provide insights into the underlying symmetries and interactions at the quantum level.
Combinations with antimuons
There are no stable composite particles where an antimuon is an integral part of it, although models are studied where a muonium is transformed into an antimuonium.
The formation of muonium and antimuonium involves the binding of a lepton (muon or antimuon) with its corresponding antiparticle, an electron or a positron, respectively. Both muonium and antimuonium are short-lived due to the relatively short lifetime of muons. Muonium is particularly interesting for studying fundamental physics, including the determination of fundamental constants and testing quantum electrodynamics (QED) predictions. However, the short lifetime of muons limits the stability of muonium, and it decays through processes involving the muon.
The notation for muonium and antimuonium can be expressed as follows:
In these expressions, μ+ and μ− represent the positive and negative muons, while e− and e+ represent the electrons and positrons, respectively. The combination of these particles forms the muonium and antimuonium atoms.
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Figure 244 - Muonium-to-Antimuonium Transition
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Creation of antimuons
Muons are typically created through various processes involving high-energy interactions and particle decays. Here are some key processes where muons are commonly produced:
Cosmic Ray Interactions:
Muons are frequently created in the Earth's atmosphere due to the interaction of high-energy cosmic rays with atmospheric particles.
Cosmic rays, which are primarily composed of protons and other high-energy particles from space, collide with nuclei in the Earth's atmosphere, producing a cascade of secondary particles, including muons.
Particle Collisions in Accelerators:
Muons can be produced in particle accelerators, where high-energy beams of protons or other particles collide.
In these collisions, a variety of particles are generated, and muons can be created as part of the decay products or in interactions involving other particles.
Pion Decay:
Pions (π⁺, π⁻, and π⁰), which are mesons composed of quarks and antiquarks, can decay into muons.
For example, the decay of a π‾ can produce a antimuon and a anti muon neutrino:
Tau Decay:
Tau leptons can decay into antimuons, contributing to the production of antimuons in certain particle interactions.
The decay of an anti-tau lepton can lead to the creation of an antimuon, along with antimuon neutrinos:
J/ψ Meson Decay:
The J/ψ meson, a bound state of a charm quark and a charm antiquark, can decay into muon-antimuon pairs. The decay process J/ψ → μ⁺ + μ⁻ is a common signature used in experiments studying charm physics.
Z Boson Decay:
The Z boson, one of the carriers of the weak force, can decay into muon-antimuon pairs. The process Z⁰ → μ⁺ + μ⁻ is a well-studied channel in experiments probing the properties of the weak force.
W Boson Decay:
W bosons, also carriers of the weak force, can mediate processes leading to muon production. In certain interactions, a W⁺ or W⁻ boson can decay into a muon and its corresponding neutrino: W⁺ → μ⁺ + νₘ.
B Meson Decay:
B mesons, composed of a bottom quark and a lighter antiquark, can decay into muons.
Figure 245 – Pion (π‾ ) decay creation an antimuon
Figure 246 – Tau ( ) decay creating an antimuon
Figure 247 - J/ψ Meson Decay creating an antimuon
Figure 248 - Z-boson decay creating antimuon
Figure 250 - B-meson decay creating an antimuon
Figure 249 - W-boson decay creating antimuon
Decay of the antimuon
The dominant muon decay mode (sometimes called the Michel decay after Louis Michel) is the simplest possible: the muon decays to an electron, an electron antineutrino, and a muon neutrino. Antimuons, in mirror fashion, most often decay to the corresponding antiparticles: a positron, an electron neutrino, and a muon antineutrino. In formulaic terms, these two decays are:
The mean lifetime, τ = ħ/Γ, of the (positive) muon is 2.1969811±0.0000022 μs. The equality of the muon and antimuon lifetimes has been established to better than one part in 10^4.
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Figure 251 - antimuon decay
Annihilation of antimuons
Muon annihilation refers to the process in which an antimuon (μ⁻, the antimatter counterpart of the muon) and a muon (μ⁺) come into close proximity and annihilate each other. The annihilation process is governed by the principles of quantum field theory and is mediated by the electromagnetic force.
The annihilation occurs through the following basic reaction:
In this process:
μ Muon, a subatomic particle with a positive charge.
ū: Antimuon, the antimatter counterpart of the muon with a negative charge.
2γ: Two gamma-ray photons.
The muon and antimuon, being oppositely charged, attract each other due to electromagnetic forces. When they come into close proximity, they can annihilate each other. The resulting energy is carried away by two gamma-ray photons. Gamma rays are high-energy photons, and in the context of particle annihilation, they represent the conversion of mass into energy according to Einstein's famous equation E=mc2.
(See fig. 242 in Muon annihilation)
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