[AS] Classification of Particles Flashcards
What is a fundamental particle?
A particle that has no substructure; the smallest unit of matter
What are the two types of hadrons?
Baryon, Meson
What particle type are protons and neutrons versions of, and what is the difference between them?
Nucleon; different electric charges
What type of particle is a proton?
Baryon (Hadron)
What type of particle is a neutron?
Baryon (Hadron)
What type of particles are baryons?
Hadron
What type of particles are mesons?
Hadron
What is the only stable baryon?
Proton
What does it mean for a particle to be unstable?
It can decay to become another particle
What particle do all baryons decay to?
Proton
Why don’t you find antibaryons in ordinary matter?
They only exist momentarily before being annihilated
What is the baryon number?
The number of baryons
What is the baryon number of the proton?
+1
What is the baryon number of the neutron?
+1
What is the baryon number of the antiproton?
-1
What is the baryon number of the antineutron?
-1
What is the baryon number of a particle that isn’t a baryon?
0
Must the baryon number be conserved in interactions?
Yes
Can the total baryon number in a particle interaction change?
No
What type of particle are electrons?
Leptons
Is an electron a baryon?
No
What type of particle are antineutrinos?
Leptons
What is the baryon number of an electron?
0
What is the baryon number of an antineutrino?
0
What is the baryon number of an neutrino?
0
What is the baryon number of an positron?
0
What type of particle is a Pion?
Meson (Hadron)
What type of particle is a Kaon?
Meson (Hadron)
Are mesons stable?
No
Are mesons unstable?
Yes
What is the baryon number of a meson?
0
Which is the lightest meson?
Pion
How many types of Pion are there?
Three, with different charges
π⁻, π⁺, π⁰
Where do you get a lot of Pions?
High-energy collisions
What is the mass of Kaons, relative to Pions?
They are heavier
What is the mass of Pions, relative to Kaons?
They are lighter
What is the stability of Kaons, relative to Pions?
They are more unstable
What is the stability of Pions, relative to Kaons?
They are more stable
What are some different types of Kaons?
K⁺, K⁻, K⁰
three different charges
How were Pions and Kaons discovered?
In cosmic rays
What is the source of Pions and Kaons?
Cosmic ray showers
Where can you observe the track of Pions and Kaons?
Cloud chamber
What interaction do Mesons interact with Baryons via?
Strong nuclear
What interaction do Baryons interact with Mesons via?
Strong nuclear
What are the products when a π⁻ interacts with a proton?
π⁰, neutron
What is the name of the classification of particles that feel the strong nuclear force?
Hadrons; baryons and mesons
What is the name of the classification of particles that don’t feel the strong nuclear force?
Leptons
Are electrons stable?
Yes
Are muons stable?
No
Are muons unstable?
Yes
Are electrons unstable?
No
What do muons eventually decay into?
Electrons
What is the neutrino of an electron?
v̅e
What is the neutrino of an muon?
v̅μ
What is the mass of a neutrino?
Almost zero
What is the charge of a neutrino?
Zero
What forces do neutrinos interact by?
Weak nuclear
What could a neutrino notably pass through without anything happening?
The Earth
What are the different types of Lepton number?
Le and Lμ
What is the opposite for lepton-antilepton pair?
Charge, lepton number
What is the same for lepton-antilepton pair?
Mass, rest energy
What is the charge on a μ⁻?
-1
What is the Le of a μ⁻?
0
What is the Lμ of a μ⁻?
+1
What is the Lμ of a μ+?
-1
What is the charge on a μ+?
+1
What is the exchange particle of the electromagnetic interaction?
Virtual photon γ
What is the exchange particle of the weak interaction?
W-boson
What is the exchange particle of the strong interaction?
Pions
Are pions stable?
No
Are kaons stable?
No
What do kaons decay to?
Pions
What is the Le of an electron?
+1
What is the Le of an electron-neutrino?
+1
What are quarks?
The fundamental particle (‘building blocks’) for hadrons
When is strangeness conserved?
In the strong interaction
Is strangeness conserved in the strong interaction?
Yes
Is strangeness conserved in the weak interaction?
No
How many quarks are baryons made of?
3
What is the quark structure of a proton?
uud
What is the quark structure of a neutron?
udd
What is the quark structure of a meson?
Quark and antiquark
What is the quark composition of a π+ ?
up / anti-down
What is the quark composition of a π0 ?
up / anti-up
OR
down / anti-down
What is the quark composition of a π- ?
down / anti-up
What is the strangeness of a pion?
Zero
What is the quark composition of a K+ ?
up / anti-strange
What is the quark composition of a K0 ?
down / anti-strange
What is antiparticle of a K+ ?
K-
What is antiparticle of a K- ?
K+
Can you have a single quark on its own?
No
