課程名稱︰量子物理下
課程性質︰大三必修
課程教師︰侯維恕
開課學院：理學院
開課系所︰物理系
考試日期（年月日）︰96.06.20
考試時限（分鐘）：150min
是否需發放獎勵金：yes
試題 :
1.Tritium beta decay 1H3->2He3 + e + antineutrino
releases energy Δ=0.0186Mev
a)Draw the nuclear, nucleon and quark level decay diagrams.
b)Estimate Vmax of 2He3(電子質量>>反微中子質量) recoil. Will the orbital e-
be affected?
c)Sketch the Ke spectrum. If m(反微中子)!=0, how would the spectrum be?
2.a)Why are neutrinos emitted in a supernova explosion?
Assuming a ~4E30 kg neutron star remnant, and average neutrino energy~5Mev,
estimate the total energy carried away by neutrinos.
b)Underground "watertank" detectors saw neutrinos from supernova SN1987A
in real time. Describe the detection principle, and explain why
underground.
c)What is the bottleneck for nuclear fusion in general?
How is it resolved in the sun?
3.a)Why must the nuclear force be both strong and very short range?
b)From he fact that nn and pp do not bind, deduce the deuteron's isospin
and spin.
c)A deuteron captures a π- and disassociates into n + n.
Using s(π)=0, infer the π- intrinsic parity.
d)Give the physical argument for the pion cloud around a nucleon.
Infer the orbital state of the cloud pion, and use this to argue why
μ(p)>μ(n), while μ(n)< 0 physically.
4.a)The Large Hadron Collider colliders two 7 TeV proton beams head-on.
What is the equivalent beam energy for proton on a liquid H2 target?
_
b)For p production from proton on liquid H2 target, find the minimum beam
energy.
c)Describe how a νμ beam is made.
_ _
d)The top quark is discovered in pp -> tt + X at the Ecm=1800 GeV Tevatron
_
pp collider. Draw the production process(es) at the fundamental
quark/parton level.
5.a)Give the lowest Jp = 0-, 1-, 1/2+, 3/2+ hadron multiplets in the
I3(or Tz) Y plot.
b)Give the quark content for(a), and show Gell-Mann-Nishijima formula is
satisfied.
c)How does each member of the Δ isoquartet decay? Illustrate
diagrammatically.
d)Why must Ω decay weakly? Illustrate diagrammatically for 3 possible final
states.
+ 0 0 +
e)What do the τ -> pπ , Λ π decays violate?
Closed Book, Closed Notes.
1,2: 15 pts; 3,4: 20 pts; 5: 30 pts.
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