Particle Reactions Flashcards
what conservations need to be upheld during a reaction involving particles
- the conservation of mass + energy
- the conservation of momentum
- the conservation of charge
why is it difficult to confirm mass/energy conservations
- because the reaction can overcome any apparent mass difference in different ways
- such as the particles having more kinetic energy
regarding the particles and forces topic, what numbers must also be conserved
- baryon number
- lepton number
what would be the product of 235/92 uranium (U) going through alpha decay (you dont need to know the element itself just the numbers)
- an alpha particle has an atomic mass of 4 and number of 2
- 235 - 4 = 231
- 92 - 2 = 90
- 235/92 U = 4/2 a + 231/90 X
what is the principle we have used in order to decipher the decay of uranium
- the conservation of charge
- 92 on the left = 90 + 2 on the right
what would be the product of 14/6 C going through beta minus decay
- a beta- particle has an atomic mass of 0 and number of -1
- 14 - 0 = 14
- 6 - (-1) = 7
- 14/6 C = 14/7 N + 0/-1 b- +0/0 v-bar(e)
what do i mean by v-bar(e)
- v(e) is the symbol for an electron neutrino
- so v-bar(e) is saying that theres a bar above the v
- indicating an anti-electron neutrino
why are anti-neutrinos like that one almost impossible to observe
- they are almost massless and have no charge
- so they really hard to detect
what was the evidence for neutrinos or anti-neutrinos also being emitted during beta decays
- the same isotope going through the same beta decay shouldve given the beta particle the same kinetic energy all the time
- however this wasnt the case, the beta particles had a range of KEs
- this suggested that another particle was being emitted from the isotope with some KE
- these particles were the neutrinos
what is important to note about the relationship between the beta particle and the emitted neutrino
- for the same isotope going through the same beta decay
- the sum of the beta and neutrino particles KE was always the same
what is the lepton number of all the leptons we mentioned in the earlier deck (electron / muon / tau)
1
what is the baryon number of all the leptons we mentioned in the earlier deck (electron / muon / tau)
0
what is the lepton number of all the anti-particles of the leptons mentioned earlier
-1
what is the baryon number of all the anti-particles of the leptons mentioned earlier
0
what are the lepton and baryon numbers of a proton
- lepton number = 0
- baryon number = +1
what are the lepton and baryon numbers of a neutron
- lepton number = 0
- baryon number = +1
what is the charge, lepton and baryon numbers of a neutral pion, pi(0)
- charge = 0
- lepton number = 0
- baryon number = 0
what is the charge, lepton and baryon numbers of a pi-plus particle, pi+
- charge = +1
- lepton number = 0
- baryon number = 0
what are the lepton and baryon numbers of a down quark
- lepton number = 0
- baryon number = +1/3
what are the charges, lepton and baryon numbers of a xi-minus particle
- charge = -1
- lepton number = 0
- baryon number = +1
cba to write em all, so what should you know about the charges, lepton and baryon numbers of all of their anti-aprticles
its just the same number but with the opposite sign
what other property / particle needs to be conserved in reactions
- strangeness
- aka the strange quark
what are the strangeness numbers of a strange quark and anti-strange quark
- strange quark = -1
- anti-strange quark = +1
what is the strangeness number of all other particles
0
