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Higher Physics > The Standard Model > Flashcards

The Standard Model Flashcards

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1
Q

what is the standard model?

A

model that explains what the Universe is made from and what holds it together

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2
Q

what does the standard model consist of?

A

6 quarks, 6 leptons and 4 force carrier particles

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3
Q

what is meant by a ‘fundamental’ particle

A

a particle which cannot be subdivided

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4
Q

what are fermions?

A

leptons and quarks (matter particles)

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5
Q

what are hadrons?

A

particles made up of quarks

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6
Q

what is a baryon?

A

particle made up of 3 quarks

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7
Q

examples of baryons

A

proton (u,u,d)

neutron (u,d,d)

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8
Q

what is a meson?

A

particle made up of one quark and one antiquark

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9
Q

example of a meson

A

pion (π+)

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10
Q

antimatter

A

for every type of particle, there is a corresponding antiparticle that looks and behaves the same but has the opposite charge

annihilate into pure energy when they meet

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11
Q

evidence for the neutrino

A

beta decay

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12
Q

what are the four interactions?

A
  1. strong force
  2. weak force
  3. gravitational force
  4. electromagnetic force
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13
Q

name the 6 quarks

A
  1. up
  2. down
  3. charm
  4. strange
  5. top
  6. bottom
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14
Q

quarks only exist…

A

bound together

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15
Q

combinations of quarks only exist when…

A

the overall charge is a whole number

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16
Q

why are quarks difficult to detect?

A

they have very short lifetimes

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17
Q

charge of up, charm and top quarks

A

+2/3

18
Q

charge of down, strange and bottom quarks

A

-1/3

19
Q

how to matter particles interact?

A

by exchanging force carrier particles

20
Q

is the standard model a good theory?

A

yes - experiments have verified its predictions and all particles predicted by theory have been found
no - it does not explain everything, eg: gravity

21
Q

name the 6 leptons

A
  1. electron
  2. muon
  3. tau
  4. electron neutrino
  5. muon neutrino
  6. tau neutrino
22
Q

neutrinos

A
  • have no electrical charge
  • mostly pass through Earth without interacting with any atoms
  • produced in great abundance in the early Universe
  • have tiny mass
  • huge numbers contribute to the total mass of the Universe
23
Q

leptons exist…

A

on their own

24
Q

charge of electron, muon and tau

A

-1

25
Q

charge of neutrinos

A

0

26
Q

how to denote antimatter

A

adding a bar above the symbol or changing sign

27
Q

anti particle of electron

A

positron

28
Q

PET Scanners

A

Positron Emission Tomography

use antimatter particles (positrons) produced by radioactive tracers, to produce three dimensional images of the inside of the patient’s body

29
Q

gravity and antimatter

A

gravity affects matter and antimatter in the same way as gravity is not a charged property and a matter particle has the same mass as its antiparticle

30
Q

discovery of the neutrino

A
  • in the 1930s, the beta decay of the nucleus was studied closely
  • it was discovered that the total energy before and after did not match expectations leading Enrico Fermi to propose that another particle was involved
  • the particle would have very small mass and no charge neutrino
31
Q

beta decay of nucleus steps

A
  1. neutron is made of one up quark and two down quarks
  2. one the the down quarks is transformed into an up quark. the difference in charge is conserved by the emission of a W- boson
  3. the neutron has become a proton
  4. the W- boson is very short lived and decays into an electron and an electron anti-neutrino
  5. the proton, electron and anti-neutrino move away from each other, emitting the electron as a beta particle.
32
Q

electromagnetic force

A
  • causes like-charged things to repel and oppositely-charged things to attract
  • many everyday forces such as friction are caused by the electromagnetic force
  • acts of infinite distances
  • greater charge=greater force / greater distance=smaller force
33
Q

electromagnetic force charge carrier

A

photon

has zero mass and travels at speed of light

34
Q

gravitational force

A
  • standard model cannot explain gravity
  • it is the force of attraction between all massive objects in the Universe
  • it is by far the weakest of the forces but infinite in range
35
Q

gravitational force charge carrier

A

has never been detected but has been given the name the graviton

36
Q

weak force

A
  • responsible for the decay of massive quarks into lighter quarks and leptons
  • has very short range and is only effective within the radius of the nucleus
  • around 25 orders of magnitude greater than the gravitational force.
37
Q

weak force charge carrier

A

W+, W- and Z bosons

z bosons have no charge

38
Q

strong force

A
  • reason why positively charged particles inside the atom don’t repel and blow apart the nucleus
  • holds quarks together to form hadrons
  • strong only over short distances
39
Q

strong force charge carrier

A

gluon (GLUES quarks together)

has no mass or charge

40
Q

what are bosons?

A

the particles which give rise to forces

Higher Physics (23 decks)

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