2.2- PARTICLE SORTING

Question 1

How were the newly discovered particles created?

Answer 1

through high-energy interactions

Question 2

What did the newly discovered particles decay into, apart from the neutrino?

Answer 2

into other particles and antiparticles

Question 3

In what numbers were charged pions often produced in?

Answer 3

in pairs

Question 4

As pions were produced in twos what did this lead to?

Answer 4

lead to the conclusion that π+ meson and π- meson are a particle-antiparticle pair

same conclusion for charged kaons

Question 5

What is the antiparticle of charged pions?

Answer 5

charged pions are antiparticles of each other

Question 6

How are particles and antiparticles divided?

Answer 6

divided into two groups called hadrons and leptons

Question 7

How are particles and antiparticles separated between hadrons and leptons?

Answer 7

according to whether or not they interact through the strong interaction

Question 8

What are hadrons?

Answer 8

particles and antiparticles that can interact through the strong interaction

Question 9

What are examples of hadrons?

Answer 9

protons, neutrons, π mesons, K mesons

Question 10

What are leptons?

Answer 10

particles and antiparticles that do not interact through the strong interaction

Question 11

What are examples of leptons?

Answer 11

electrons, muons and neutrinos

Question 12

How do leptons interact?

Answer 12

through:

weak interaction 
gravitational interaction
electromagnetic interaction (if charged)

Question 13

How do hadrons interact?

Answer 13

through all 4 fundamental interactions

through strong interaction and electromagnetic interaction if charged

Question 14

Why do protons not decay?

Answer 14

they are stable

Question 15

Through what interaction do hadrons tend to decay through?

Answer 15

weak interaction

Question 16

What is the Large Hadron Collider?

Answer 16

ring-shaped accelerator that boosts the kinetic energy of charged particles in ring at several places round it

Question 17

Why are there fixed magnets around the Large Hadron Collider?

Answer 17

they bend the path of the particles to keep them in the ring

Question 18

What happens when particles in the Large Hadron Collider collide with other particles? (2) (equations)

Answer 18

total energy of particles + antiparticles before collision = their rest energy + their KE

total energy of particles + antiparticles after collision = their rest energy + their KE

Question 19

What is the equation for conservation of energy?

Answer 19

rest energy of products = total energy before - KE of products

Question 20

When kaons are created what may also be produced?

Answer 20

short-lived particles with greater rest masses than protons

Question 21

How are the short-lived particles from when kaon are created, created?

Answer 21

through strong interactions

Question 22

As the short-lived particles from the kaon creations are created through strong interactions, what are they?

Answer 22

hadrons

Question 23

How are the short-lived particles different from kaons?

Answer 23

decay into protons and pions

Question 24

Into what two groups can hadrons be divided into?

Answer 24

baryons and mesons

Question 25

What are baryons?

Answer 25

protons and all other hadrons (including neutrons) that decay into protons either directly or indirectly

Question 26

What are mesons?

Answer 26

hadrons that do not include protons in their decay products. In other words kaons and pions are not baryons

Question 27

What are baryons and mesons composed of?

Answer 27

smaller particles called quarks and antiquarks