Classification of Particles 60-61

Question 1

What are the name of the types of particles that can feel the strong interaction?

Answer 1

The ones called hadrons.

Question 2

What are the two types of hadron?

Answer 2

Baryons and mesons

Question 3

What is the name of the fundamental particles that make up hadrons?

Answer 3

Hadrons are made from smaller particles called quarks.

Question 4

What do all baryons decay to?

Answer 4

All baryons decay to a proton. But a proton (a baryon) does not decay to a proton.

Question 5

What is the Baryon number?

Answer 5

The number of baryons.

Question 6

What is the baryon number for a neutron and a proton?

Answer 6

The proton and the neutron each have a baryon number of B = +1.

Question 7

Does the total baryon number change in a reaction?

Answer 7

The total baryon number in any particle reaction never changes.

Question 8

What are leptons?

Answer 8

Leptons are fundamental particles and they don’t feel the strong interaction. The only way they can interact with other particles is via weak interaction and gravity. ( electromagnetic force if they are charged.)

Question 9

Name three leptons.

Answer 9

Electrons(e^- ), muon(µ^-), tau(T^-)

Question 10

Muons and taus are unstable and eventually decay into what?

Answer 10

They eventually decay into electrons.

Question 11

What are neutrinos?

What are their properties?

What contains them?

Answer 11

The electron, muon and tau each come with their own neutrino: v_e, v_{µ and Vt.}

Neutrinos have zero or almost zero mass and zero electric charge-so they don’t do much. In fact, a neutrino can pass right through the Earth without anything happening to it.

Question 12

Make a table with the columns of : Symbol, Charge, L_e, L_µand L_T.

Fill the table out for the following leptons:

Electron, electron neutrino, muon, muon neutrino, tau and tau neutrino.

Answer 12

Table is in page 61 of the book.

Question 13

Write out the equation for Beta-minus decay.

Answer 13

n ⇒ p + e^- + /v_e

/v_eis the antineutrino has a L_e = -1 which means its an antiparticle.

Question 14

What is the half life of free neutrons ( ones not held in a nucleus. )?

Answer 14

They have a half life of about 15 minutes.