Particle Model, Standard Model, Cosmology

Question 1

What are elementary particles?

Answer 1

Particles that have no internal structure and cannot be divided into smaller components

Question 2

What family of elementary particles do electrons belong to?

Answer 2

Leptons

Question 3

Is a photon an elementary particle?

Answer 3

Yes

Question 4

What mass does a photon have?

Answer 4

Zero

Question 5

Why are protons and neutrons not elementary particles?

Answer 5

They can be broken into smaller components and a neutron has a magnetic field even though it it uncharged, suggesting it is made of smaller, charged particles

Question 6

What happens when a particle meets its anti particle?

Answer 6

They annihilate, producing photons

Question 7

How are high energy particles detected?

Answer 7

They cause ionisation of the material they pass though.

Question 8

How are particle accelerators used to create new particles?

Answer 8

They collide high energy charged particles with a target such as a particle or nucleus

Question 9

What are the two types of hadrons?

Answer 9

Mesons and baryons

Question 10

What must be conserved in particle reactions?

Answer 10

Energy, momentum, angular momentum, lepton number, charge , baryon number

Question 11

What baryon number do baryons always have?

Answer 11

+1

Question 12

What baryon number do anti baryons always have?

Answer 12

-1

Question 13

What baryon number do non baryon particles always have?

Answer 13

0

Question 14

What is antimatter?

Answer 14

Matter composed of anti particles

Question 15

What is an antiparticle?

Answer 15

Each particle has an opposite particle with the same mass but opposite charge and magnetic moment.

Question 16

What is a boson?

Answer 16

A particle with an integer spin. Examples are exchange particles

Question 17

What are exchange particles?

Answer 17

Particles that mediate interactions

Question 18

What is a fermion?

Answer 18

Particle with a half integer spin

Includes protons, neutrons, electrons

Question 19

What is a linear accelerator/linac?

Answer 19

A device in which electric and magnetic fields are used to accelerate charged particles at high speeds in a straight line

Question 20

What is the strong nuclear force?

Answer 20

The force that acts between proton and neutrons to hold a nucleus together.

Question 21

What mediates the strong nuclear force?

Answer 21

Pions

Question 22

What is the weak force?

Answer 22

The force necessary of beta decay of nuclei.

Question 23

What is the weak force mediated by?

Answer 23

W and Z bosons

Question 24

How are W and Z bosons different from photons?

Answer 24

W and z bosons have mass

Question 25

What does the standard model describe?

Answer 25

The elementary particles of which matter is made and the forces with which they interact

Question 26

What are all hadrons composed of?

Answer 26

Quarks

Question 27

What are the six quarks flavours?

Answer 27

Up, down, top, bottom, charm, strange

Question 28

What are meson composed of?

Answer 28

One quark and one antiquark

Question 29

What are baryons composed of?

Answer 29

Three quarks

Question 30

What are anti baryons composed of?

Answer 30

Three anti quarks

Question 31

What force are photons exchange particles for?

Answer 31

Electromagnetic force

Question 32

What force are W and Z photons exchange particle for?

Answer 32

The weak force

Question 33

What force are gluons exchange particles for?

Answer 33

The strong force

Question 34

Is the strong force that same as this strong nuclear force?

Answer 34

No

Question 35

How do particles acquire mass?

Answer 35

Via interactions with the Higgs field.

Question 36

What is the mediating particle when particles gain mass?

Answer 36

The Higgs boson

Question 37

What are the limitations of the standard model?

Answer 37

It does not include a theory for Gravity | It predicts that neutrinos should be massless when they actually have some mass

Question 38

What is the evidence for an expanding universe?

Answer 38

The red shift

Question 39

When where particles formed?

Answer 39

In the first seconds after the Big Bang.

Question 40

What is cosmic microwave background radiation?

Answer 40

The observed radiation coming from all points in space

Question 41

What is the cosmological principle?

Answer 41

The assumption that all matter is uniformly distributed through the universe on all scales

Question 42

What is dark energy?

Answer 42

Energy that is predicted from the increasing rate of expansion of the universe

Question 43

What is dark matter?

Answer 43

The matter that is postulated to explain gravitational effects but is not observable by the emission or reflection of light

Question 44

What is redshift?

Answer 44

The observed shift to longer wavelengths of spectral lines in distant stars

Question 45

What is the singularity?

Answer 45

A point in space and time at which the density of matter/energy is infinite and the volume is infinitesimally small

Question 46

What are the forces included in the standard model?

Answer 46

Strong force, weak force, electromagnetic force | NOT GRAVITY

Question 47

Why are we not able to see parts of the universe more than 700000 years old?

Answer 47

It consisted of matter and exchange particles Photons that existed were constantly absorbed and emitted in interactions Universe opaque to photons, not visible When atoms formed light could be absorbed therefore seen

Question 48

Baryons are the ____________ of the particles

Answer 48

Heaviest

Question 49

Are baryons fundemental?

Answer 49

No

Question 50

Do quarks appear to have volume?

Answer 50

No

Question 51

What direction do positive particle curl in a bubble chamber?

Answer 51

To the right