2.3 - Leptons at work

Question 1

describe the production of hadrons from leptons

Answer 1

a high energy, head-on collision between a lepton + antilepton can produce hardons

• this event produced quarks & antiquarks moving in opposite directions, producing a shower of hadrons in each direction

Question 2

describe neutrinos (4)

Answer 2

• travel almost at the speed of light
• highly unreactive
• annihilation occurred when a neutrino and antineutrino collide
• are specific to a certain lepton

Question 3

describe how the experiment that found neutrinos was affected by a nearby nuclear reactor

Answer 3

reactor on = increased neutrino flow (moe=re light produced)

off = decreased

Question 4

how were different types of neutrinos/antineutrinos discovered

Answer 4

the V produced in muon decays differed from those produced in beta decays

V in muon decays didn’t produce e- when they interacted with protons/neutrons

if there was one type, equal no. of leptons would be produced

Question 5

how can leptons change into other leptons

• what will all leptons change into

Answer 5

by decay process, the weak interaction

• e+ / e-

Question 6

how can leptons be produced from ‘non-leptons’

Answer 6

though annihilation between particles and antiparticles

• products total energy determines the lepton that can be produced

Question 7

describe how a lepton can change to a corresponding neutrino and vise-verse

Answer 7

an interaction between a hadron and a lepton OR its corresponding neutrino

Question 8

give the equation for µ- & µ+ decay

Answer 8

µ- –> e- + Ve + _V_µ

µ+ –> e+ + Ve + Vµ

V = antineutrino

Question 9

how can you tell the difference between leptons and antileptons

Answer 9

they will have opposite charges

leptons = -

antileptons = +