Particles and Radiation (2): Quarks and Leptons Flashcards
What are Leptons?
The group of light /weak fundamental particles that interact through the weak interaction, gravitational interaction and electromagnetic interaction (if charged)
What are Hadrons?
The group of strong/heavy fundamental particles that are created through the strong interaction and interact through all four fundamental forces but primarily the strong interaction and the electromagnetic interaction (if charged).
What are the two classifications of Hadrons?
Baryons and Mesons
What is the definition of a Baryon?
Subatomic particles, which are a subsection of Hadrons, that are comprised of 3 quarks and decay into protons directly or indirectly
What is the definition of a Meson?
Subatomic particles, which are a subsection of Hadrons, that are comprised of 2 quarks (a quark and antiquark) that don’t decay into protons
What are examples of Baryons?
Nucleons - protons and neutrons
Other - other subatomic particles that are comprised of 3 quarks
What are the 2 mesons you need to know?
Pions (pi symbol) and Kaons (capital K)
What are the 2 leptons you need to know?
Electrons and muons
What is the only fundamental particle that is stable on its own?
proton
What are the 6 types of quarks?
up, down, top, bottom, strange, charm
Why cant you have one quark in isolation?
As the energy required to overcome the forces between the 2 quarks would spontaneously create another one
What are the conservation laws associated with interactions of subatomic particles?
- Conservation of charge
- Conservation of lepton number
- Conservation of Baryon number (work this out by calculating the baryon number on either sides with the individual baryon number of each quark)
- Conservation of strangeness
What is interesting about the conservation of strangeness?
Strangeness has to be conserved in strong force interactions but can differ by +/-1 in weak force interactions
What type of neutrino can a muon only turn into?
muon neutrino
What type of neutrino can an electron only turn into?
electron antineutrino
What is the lepton number of an electron, muon and neutrino?
+1
NB - the electron neutrino has a +1 electron lepton number but a 0 muon lepton number. The muon neutrino has a +1 lepton number but a 0 electron lepton number.
What is the lepton number of a positron, anti muon and antineutrino (electron/muon)
-1
NB - The electron antineutrino has a -1 electron lepton number but a 0 muon lepton number. The muon antineutrino has a -1 muon lepton number but a 0 electron lepton number.
What is the quark configuration of a neutron?
udd
What is the quark configuration of a proton?
uud
What classification of particle is a sigma particle?
A Baryon (hadron)
What is the quark configuration of an antiproton?
ūū(anti)d
What are the charges of each of the quarks?
u - +2/3
d - -1/3
s - -1/3
ū - -2/3
(anti)d - +1/3
(anti)s - +1/3
What is the strangeness of each of the quarks?
u - 0
d - 0
s - -1
ū - 0
(anti)d - 0
(anti)s - +1
What is the baryon number for each of the quarks?
u - +1/3
d - +1/3
s - +1/3
ū - -1/3
(anti)d - -1/3
(anti)s - -1/3
What is the quark configuration of the K0 meson?
d(anti)s
What is the quark configuration of the K+ meson?
u(anti)s
What is the quark configuration of the K- meson?
sū
What is the quark configuration of the (anti)K0 meson?
s(anti)d
What is the quark configuration of the pion0 meson?
uū, d(anti)d or s(anti)s
What is the quark configuration of the pion+ meson?
u(anti)d
What is the quark configuration of the pion- meson?
ūd
In ß- decay what happens in terms of quarks?
A down quark turns into an up quark
In ß+ decay what happens in terms of quarks?
An up quark turns into a down quark
What are the two ways that a Kaon(+/-/0) can decay?
-> Pions
-> Muon and antineutrino, antimuon and neutrino
What are the two ways that a charged Pion(+/-) can decay?
-> Muon and antineutrino, antimuon and neutrino
How does a Pion (0) decay?
-> high-energy photons
What do Muons decay into?
-> electron + antineutrino
-> positron + neutrino
What force do all Hadrons act under?
Strong force interactions
What force do all charged matter and antimatter act under?
Electromagnetic force
What force to all leptons and baryons act under?
Weak force interaction
In what number are strange particles created?
2’s
What force do W and Z bosons mediate?
Weak nuclear
What is the exchange particle that mediates the Electromagnetic force?
virtual photon
What type of interaction are strange particles formed by?
Strong nuclear force
What type of interaction do strange particles decay via?
Weak nuclear force
What are the 4 fundamental forces?
- Gravity
- SNF
- WNF
- Electromagnetic
What is the exchange particle for the SNF?
pion/gluon
