Questions from Modern Physics

Q: Beams of π- mesons are used in radiation therapy for certain

Beams of π- mesons are used in radiation therapy for certain cancers. The energy comes from the complete decay of the π- to stable particles. a. Write out the complete decay of...

Q: A proton and an antiproton collide head-on with equal kinetic

A proton and an antiproton collide head-on with equal kinetic energies. Two γ rays with wavelengths of 0.720 fm are produced. Calculate the kinetic energy of the incident proton.

Q: Calculate the threshold kinetic energy for the reaction p + p →

Calculate the threshold kinetic energy for the reaction p + p → p + p + K+ + K- if a proton beam is incident on a stationary proton target.

Q: Calculate the threshold kinetic energy for the reaction π- + p

Calculate the threshold kinetic energy for the reaction π- + p → Σ0 + K0 if a π- beam is incident on a stationary proton target. The K0 has a mass of 497.7 MeV/c2.

Q: Can a hydrogen atom emit x rays? If so, how

Can a hydrogen atom emit x rays? If so, how? If not, why not?

Q: Each of the following reactions is missing a single particle. Calculate

Each of the following reactions is missing a single particle. Calculate the baryon number, charge, strangeness, and the three lepton numbers (where appropriate) of the missing particle, and from this...

Q: An η0 meson at rest decays into three p mesons.

An η0 meson at rest decays into three p mesons. a. What are the allowed combinations of π0, π+, and π- as decay products? b. Find the total kinetic energy of the π mesons.

Q: The ϕ meson has mass 1019.4 MeV/c2 and

The ϕ meson has mass 1019.4 MeV/c2 and a measured energy width of 4.4 MeV/c2. Using the uncertainty principle, estimate the lifetime of the f meson.

Q: Estimate the energy width (energy uncertainty) of the ψ if

Estimate the energy width (energy uncertainty) of the ψ if its mean lifetime is 7.6 * 10-21 s. What fraction is this of its rest energy?

Q: One proposed proton decay is p+ → e+ + π0

One proposed proton decay is p+ → e+ + π0, which violates both baryon and lepton number conservation, so the proton lifetime is expected to be very long. Suppose the proton half-life were 1.0 * 1018 y...