1. [-/1 Points] DETAILS OSCOLPHYSZO16 33.1.P.001. MY NOTES ASK YOUR TEACHER A virtual particle having an approximate mass of 1014 GeV/c2 may be associated with the unication of the strong and electroweak forces. For what length of time in s could this virtual particle exist (in temporary violation of the conservation of mass-energy as allowed by the Heisenberg uncertainty principle)? 5 Additional Materials El Reading 2. [-11 Points] DETAILS OSCOLPHYSZO16 33.2.P.004. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER (a) Find the ratio of the strengths of the weak and electromagnetic forces under ordinary circumstances. (b) What does that ratio become under circumstances in which the forces are unied? 3. [/1 Points] OSCOLPHYSZO16 33.2.P.005. ASK YOUR TEACHER PRACTICE ANOTHER The ratio of the strong to the weak force and the ratio of the strong force to the gravitational force become 1 under circumstances where they are unified. What are the ratios of the strong force to those two forces under normal circumstances? Additional Materials II] Reading 4. [-/1 Points] OSCOLPHYSZMG 33.3.P.006. ASK YOUR TEACHER At full energy, protons in the 2.00 km diameter Fermilab synchrotron travel at nearly the speed of light, since their energy is about 1000 times their rest mass energy. (a) How long in seconds does it take for a proton to complete one trip around? 5 (b) How many times per second will it pass through the target area? 5. [I1 Points] OSCOLPHYSZO1633.3.P.007. ASK YOUR TEACHER PRACTICE ANOTHER Suppose a W' created in a bubble chamber lives for 4.00 x 10'25 5. What distance in fm does it move in this time if it is traveling at 0.8756? Since this distance is too short to make a track, the presence of the W' must be inferred from its decay products. Note that the time is longer than the given W' lifetime, which can be due to the statistical nature of decay or time dilation. fm Additional Materials III Reading 6. [-/1 Points] OSCOLPHYSZO1633.3.P.008. ASK YOUR TEACHER What length track in m does a n+ traveling at 0.100c leave in a bubble chamber, if it is created there and lives for 2.60 x 10'8 5? (Those moving faster or living longer may escape the detector before decaying.) 7. [-I1 Points] DETAILS OSCOLPHYSZO16 33.4.P.013. MY NOTES ASK YOUR TEACHER PRACTICE AN OTHER 0 The \"0 is its own antiparticle and decays in the following manner: It > y + y. What is the energy (in MeV) of each y ray if the no is at rest when it decays? MeV Additional Materials III Reading 8. [-I1 Points] DETAILS OSCOLPHYSZO16 33.4.P.014. MY NOTES ASK YOUR TEACHER The primary decay mode for the negative pion is n' > p' + 7". What is the energy release in MeV in this decay? MeV 9. [I1 Points] OSCOLPHYSZO16 33.5.P.021. ASK YOUR TEACHER PRACTICE ANOTHER (a) Verify from its quark composition that the A0 particle could be an excited state of the neutron. The A0 particle has a quark composition of ---Select--- which is the same quarks as for a neutron. (b) There is a spread of about 100 MeV in the decay energy of the A0, interpreted as uncertainty due to its short lifetime. What is its approximate lifetime (in seconds)? 5 (c) Does its decay proceed via the strong or weak force? " strong force due to its short lifetime strong force due to its long lifetime weak force due to its short lifetime weak force due to its long lifetime 10. [-/1 Points] OSCOLPHYSZO1 6 33.6.P.043. ASK YOUR TEACHER PRACTICE ANOTHER The intensity of cosmic ray radiation decreases rapidly with increasing energy, but there are occasionally extremely energetic cosmic rays that create a shower of radiation from all of the particles they create by striking a nucleus in the atmosphere as seen in the gure given below. Suppose a cosmic ray particle having an energy of 0.80 x 1010 GeV converts its energy into particles with masses averaging 500 MeV/cz. (a) How many particles are created? particles (b) If the particles rain down on a 1.00 km2 area, how many particles are there per square meter? particles/m2 11. [-/1 Points] DETAILS OSCOLPHYS2016 33.6.P.045. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER What is the wavelength of a 15-GeV electron in m, which is produced at SLAC? This provides an idea of the limit to the detail it can probe. m Additional Materials Reading 12. [-/1 Points] DETAILS OSCOLPHYS2016 33.6.P.046. MY NOTES ASK YOUR TEACHER 1 (a) Calculate the relativistic quantity y = V1 - 2/c2 for 1.00 TeV protons produced at Fermilab. (b) If such a proton created a i having the same speed, how long would its life be (in s) in the laboratory? (c) How far (in m) could it travel in this time? m13. [-/1 Points] DETAILS OSCOLPHYS2016 33.6.P.050. MY NOTES ASK YOUR TEACHER In supernovas, neutrinos are produced in huge amounts. They were detected from the 1987A supernova in the Magellanic Cloud, which is about 120,000 light years away from the Earth (relatively close to our Milky Way galaxy). If neutrinos have a mass, they cannot travel at the speed of light, but if their mass is small, they can get close. 1 (a) Suppose a neutrino with a 7 eV/c mass has a kinetic energy of 700 keV. Find the relativistic quantity Y = _2/ 2 for it. (b) If the neutrino leaves the 1987A supernova at the same time as a photon and both travel to Earth, how much sooner (in s) does the photon arrive? This is not a large time difference, given that it is impossible to know which neutrino left with which photon and the poor efficiency of the neutrino detectors. Thus, the fact that neutrinos were observed within hours of the brightening of the supernova only places an upper limit on the neutrino's mass. (Hint: You may need to use a series expansion to find v for the neutrino, since its y is so large.)