Exam 44: Quarks, Leptons, and the Big Bang

The up quark u has charge +2e/3 and strangeness 0; the down quark d has charge -e/3 and strangeness 0; the strange quark s has charge -e/3 and strangeness -1. This means there can be no baryon with:

A particle can decay to particles with greater rest mass:

Compared to the lifetimes of particles that decay via the weak interaction, the lifetimes of particles that decay via the strong interaction are:

Messenger particles of the weak interaction are called:

An example of a boson is a:

A neutral muon cannot decay into two neutrinos. Of the following conservation laws, which would be violated if it did?

A particle with spin angular momentum is called a:

The interaction $\pi$ ^- + p $\rightarrow$ K^- + $\Sigma$ ⁺ violates the principle of conservation of:

Two particles interact to produce only photons, with the original particles disappearing. The particles must have been:

Which of the following particles has a lepton number of zero?

A down quark can be changed into an up quark (plus other particles perhaps) by:

Dark matter suspected to exist in the universe because:

In order of increasing strength the four basic interactions are:

Color is carried by:

$\pi$ ⁺ represents a pion (a meson), $\mu$ ^- represents a muon (a lepon), v_e represents an electron neutrino (a lepton), and v _$\mu$ and p represents a proton a muon neutrino (a lepton). Which of the following decays might occur?

When a kaon decays via the strong interaction the products must include a:

Which of the following particles has a lepton number of +1?

As a result of the big bang there is, in addition to the microwave background radiation, a uniform distribution of background:

The stability of the proton is predicted by the laws of conservation of energy and conservation of:

An electron participates in: