Verify the quantum numbers given for the proton and neutron in Table \[33.2\] by adding the quantum numbers for their quark constituents as given in Table \[33.4\].

Short Answer

Expert verified

The quantum numbers given for proton and neutron is\[B = 1,{\rm{ }}S = 0,{\rm{ }}{L_e} = {L_\mu } = {L_\tau } = 0\]which is verified with table\[{\rm{33}}{\rm{.2}}\].

Step by step solution

01

Concept Introduction

A quark is a basic ingredient of matter and a sort of elementary particle.

Antiquarks are the antiparticles that correspond to each flavour of quark.

02

Quantum numbers for particles

Prove the quantum numbers for proton and neutron by using its quark compositions. Thus, the quantum numbers for proton and neutron from table\[{\rm{33}}{\rm{.2}}\]is –

\[{\rm{B}}\]

\[{{\rm{L}}_{\rm{e}}}\]

\[{{\rm{L}}_{\rm{\mu }}}\]

\[{{\rm{L}}_{\rm{\tau }}}\]

\[{\rm{S}}\]

\[{\rm{p}}\]

\[{\rm{1}}\]

\[{\rm{0}}\]

\[{\rm{0}}\]

\[{\rm{0}}\]

\[0\]

\[{\rm{n}}\]

\[{\rm{1}}\]

\[{\rm{0}}\]

\[{\rm{0}}\]

\[{\rm{0}}\]

\[0\]

Now, from table\[{\rm{33}}{\rm{.4}}\], the quark compositions for\[{\rm{p}}\]and\[{\rm{n}}\]is –

\[\begin{array}{l}p = \left[ {uud} \right]\\n = \left[ {udd} \right]\end{array}\]

03

Quark Compositions

So, now for proton it is obtained –

\[\begin{array}{c}B = \frac{1}{3} + \frac{1}{3} + \frac{1}{3} = 1\\S = 0 + 0 + 0 = 0\end{array}\]

Since, it is a baryon not a lepton. So, it is obtained –

\[{L_e} = {L_\mu } = {L_\tau } = 0\]

So, now for neutron it is obtained –

\[\begin{array}{c}B = \frac{1}{3} + \frac{1}{3} + \frac{1}{3} = 1\\S = 0 + 0 + 0 = 0\end{array}\]

Since, it is a baryon not a lepton. So, it is obtained –

\[{L_e} = {L_\mu } = {L_\tau } = 0\]

Therefore, from the quark compositions for\[{\rm{p}}\]and\[{\rm{n}}\], it can be proved that its quantum numbers are given in table \[{\rm{33}}{\rm{.2}}\].

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Most popular questions from this chapter

The principal decay mode of the sigma zero is \[{{\rm{\Sigma }}^{\rm{0}}}{\rm{ }} \to {\rm{ }}{{\rm{\Lambda }}^{\rm{0}}}{\rm{ + \gamma }}\]. (a) What energy is released? (b) Considering the quark structure of the two baryons, does it appear that the \[{{\rm{\Sigma }}^{\rm{0}}}\]is an excited state of the \[{{\rm{\Lambda }}^{\rm{0}}}\]? (c) Verify that strangeness, charge, and baryon number are conserved in the decay. (d) Considering the preceding and the short lifetime, can the weak force be responsible? State why or why not.

Suppose you are designing a proton decay experiment and you can detect \({\rm{50}}\) percent of the proton decays in a tank of water.

(a) How many kilograms of water would you need to see one decay per month, assuming a lifetime of \({\rm{1}}{{\rm{0}}^{{\rm{31}}}}{\rm{ y}}\)?

(b) How many cubic meters of water is this?

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(a) Show that all combinations of three quarks produce integral charges. Thus, baryons must have integral charge.

(b) Show that all combinations of a quark and an antiquark produce only integral charges. Thus, mesons must have integral charge.

The reaction \({{\rm{\pi }}^{\rm{ + }}}{\rm{ + p}} \to {{\rm{\Delta }}^{{\rm{ + + }}}}\) (described in the preceding problem) takes place via the strong force.

(a) What is the baryon number of the \({{\rm{\Delta }}^{{\rm{ + + }}}}\)particle?

(b) Draw a Feynman diagram of the reaction showing the individual quarks involved.

One decay mode for the eta-zero meson is\({{\rm{\eta }}^{\rm{0}}} \to {\rm{\gamma + \gamma }}\).

(a) Find the energy released.

(b) What is the uncertainty in the energy due to the short lifetime?

(c) Write the decay in terms of the constituent quarks.

(d) Verify that baryon number, lepton numbers, and charge are conserved.

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