7/24/2019 3rd Homework 333333

1/1

1. Consider the particles: , K, n, , , 0,,++, , , , ,

, D

, B

that you have studied in the previous homework. Youhad found the most probable decays channels. Plot all the lowest orderFeynman Diagrams corresponding to those decay channels. (Lowestorder Feynman Diagrams are the Feynman Diagrams that contain aminimum number of vertices)

2. Consider a wave function(x,y,z). In your book the differential oper-ator that generates a rotation around the z axis is derived. Carry outthe same derivation for a rotation around the xand y axis. Calculatethe commutation relation of these differential operators and show thatthey are the same as the matrices that you have calculated in the firsthomework.

3. What is the minimum proton energy required for the reactionp + p + +0 if the photon has energy 2.3104 eV? (this photon is a typ-ical photon in the Cosmic Microwave Background(CMB). Protons thathave energy higher then the found limit rapidly lose energy throughinteractions with the photons of the CMB.)

Questions From the Book

4. The solar constant (the rate at which energy is incident on the Earth)is about 2cals/cm2 each minute. The fusion of hydrogen to helium inthe Sun produces 26 M eVenergy for every Helium atom formed, plustwo neutrinos carrying only a small percentage of energy. Calculatethe expected solar neutrino flux at the Earth.

5. The cross-section for the reaction +p + K0 at 1GeV incidentmomentum is about 1mb (1027 cm2). Both andK0 particles decaywith a mean lifetime of order 1010 s. From this information, estimatethe relative magnitude of the couplings responsible for the productionand decay, respectively, of these strange particles.

1