Particles/antiparticles

Question 1

what is antimatter

Answer 1

its made of antiparticles. all particles have antiparticles. they have the same mass and energy but opposite charge

Question 2

antiparticles of protons, neutrons, electrons and neutrinos

Answer 2

anti-proton
anti-neutron
positron
anti-neutrino

Question 3

how are antiparticles notated

Answer 3

with a line above the regular notation

Question 4

what are the four fundamental forces

Answer 4

weak force
strong force
electromagnetism
gravity

Question 5

what is the weak force

Answer 5

it affects all particles. it’s responsible for beta plus/minus decay. it’s very weak and short-ranged

Question 6

what is the strong force

Answer 6

the strongest of the four forces but is very short-ranged. only experienced by hadrons. its attractive is the distance is over 0.5fm and repulsive is less

Question 7

what is gravity

Answer 7

the weakest of the four forces, experience by all matter. Purley attractive force

Question 8

what is the electromagnetic force

Answer 8

it’s very strong and very long-ranged. it’s responsible for the interaction between charged objects. most forces we experience are because of it

Question 9

what is an exchange particle

Answer 9

the particles responsible for the interaction between two forces

Question 10

the fundamental forces exchange particles

Answer 10

strong- gluon, pions
weak- W+ , W- , Z^0 bosons
electromagnetism- virtual photon (Y)
gravity- unknown

Question 11

why is it called a virtual photon

Answer 11

it only exists fora very short time.

Question 12

what direction to exchange particles travel for objects to feel a force

Answer 12

away from each other

Question 13

whats a Feynman diagram

Answer 13

diagrams that represent particle interactions

Question 14

rules for drawing a Feynman diagram (7)

Answer 14

1. particles move upwards
2. particles have straight lines
3. exchange particles have wiggle lines
4. hadrons on left, leptons on right
5. particles cant cross paths
6. charge entering equals the charge exiting
7. a W+ from left to right is same as W- from right to left

Question 15

what is beta minus decay (Feynman diagram)

Answer 15

a neutron decays into a proton and a W- boson which decays into an electron and antineutrino

Question 16

what is beta plus decay (Feynman diagram)

Answer 16

a proton decays into a neutron and a W+ boson which decays into a positron and neutrino

Question 17

difference between electron capture and an electron-proton collision on a Feynman diagram

Answer 17

the boson. W+ for capture and W- for collision

Question 18

what is a hadron

Answer 18

particles that feel the strong nuclear force, they are made of quarks

Question 19

what are baryons

Answer 19

a type of hadron made of 3 quarks. protons are the only stable baryon. all others will eventually decay into protons

Question 20

what is a quantum number

Answer 20

a number that can only be an integer

Question 21

waht is the baryon number

Answer 21

a number (B) that notates the number of baryons present. its a quantum number. it must be conserved

Question 22

what are mesons

Answer 22

a type of hadron made of a quark and antiquark. they have a baryon number B=0 (they aren’t baryons)

Question 23

what are pions and kaons

Answer 23

types of mesons. pions are the exchange particles of the strong force. kaons are massive pions and will decay into pions. notations- π+ , π- , π^0(pions) or K+ , K- , K^0 (kaons)

Question 24

what are leptons

Answer 24

fundamental particles (not made of smaller particles). they don’t feel the strong nuclear force. (e.g. electrons, neutrinos)

Question 25

what are muons

Answer 25

a type of lepton. negative charge, heavier than electrons, unstable and decay into electrons

Question 26

what are neutrinos

Answer 26

a type of lepton. electrons and muons have there own types of neutrino (Ve and Vμ). they are almost massless and have zero charges.

Question 27

whats the lepton number

Answer 27

a number(Le or Lμ) notating the number of leptons. it’s different for each type of lepton. its a quantum number. each must be conserved individually.

Question 28

what is strangeness

Answer 28

a property of matter. its a quantum number. strange quarks have strangeness -1 and the anti versions have +1. its only conserved in the strong interaction

Question 29

how are strange particles made and decay

Answer 29

they are made by the strong interaction but decay via the weak one which is why they are produced in pairs

Question 30

the fundamental properties of matter

Answer 30

charge
mass
strangeness
baryon number

Question 31

the three types of quarks

Answer 31

up
down
strange

Question 32

properties of the three quarks

Answer 32

name: symbol: charge: baryon number: strangeness:
up u 2/3 1/3 0
down d -1/3 1/3 0
strange s -1/3 1/3 -1

Question 33

properties of antiquarks

Answer 33

opposite to regular versions. and the symbols have a line over the top

Question 34

what is a proton made of

Answer 34

two up and one down quarks. charge adds to +1 and baryon number adds to +1

Question 35

what is a neutron made of

Answer 35

two down and one up quarks. charge adds to 0 and baryon number adds to +1

Question 36

what are antiprotons and antineutrons made of

Answer 36

the same quarks but their anti versions. the charge of the anti-proton adds to -1 and antineutron to 0. the baryon number of both adds to -1

Question 37

what are pions and kaons made of

Answer 37

pions have up and down (and anti version) quarks only

kaons have one strange/ anti-strange quark

Question 38

can quarks change type

Answer 38

yes- via the weak interaction

Question 39

how do we know that beta decay governed by the weak force

Answer 39

a proton decays into a neutron or a neutron decays into a proton meaning a quark has to change type which can only be down by the weak force