Question
The failure of theories of this force based on the spontaneous symmetry breaking of SU(2) (“S-U-two”) motivated the development of the Glashow–Weinberg–Salam (“sah-LAHM”) model. For 10 points each:
[10e] What force that is unified with the electromagnetic force at high energies is mediated by the W and Z bosons?
ANSWER: weak force [or weak nuclear force; weak interaction; accept electroweak interaction]
[10h] These electroweak interactions are responsible for the decay of a strange B meson into a muon (“MEW-on”) pair. The suppression of these interactions means the decay of a neutral kaon (“KAY-on”) into a muon pair is much rarer than the decay of a neutral kaon into a muon and neutrino.
ANSWER: flavor-changing neutral currents [or FCNCs; prompt on neutral currents; prompt on descriptions of the exchange of a Z0 boson; prompt on descriptions of interactions mediated by a Z0 boson]
[10m] The group “SU(2) (“S-U-two”) cross this group, as generated by weak hypercharge,” is the symmetry group of the electroweak interaction. This group is the symmetry group of quantum electrodynamics.
ANSWER: U(1) (“U-one”) [accept U(1) sub Y]
Data
| Team | Opponent | Part 1 | Part 2 | Part 3 | Total |
|---|---|---|---|---|---|
| Brown A | Florida A | 10 | 0 | 10 | 20 |
| Chicago A | Chicago B | 10 | 0 | 10 | 20 |
| Claremont A | Illinois A | 10 | 0 | 0 | 10 |
| Cornell A | Ohio State A | 10 | 10 | 10 | 30 |
| Cornell B | Indiana A | 10 | 0 | 10 | 20 |
| Georgia Tech B | South Carolina A | 10 | 0 | 0 | 10 |
| MIT A | Northwestern A | 10 | 0 | 0 | 10 |
| Maryland A | WUSTL A | 10 | 0 | 0 | 10 |
| Minnesota B | Columbia B | 10 | 0 | 0 | 10 |
| NYU A | Michigan A | 10 | 0 | 0 | 10 |
| North Carolina A | Harvard A | 10 | 0 | 10 | 20 |
| Penn A | Yale B | 10 | 0 | 0 | 10 |
| Penn State A | McGill A | 10 | 0 | 10 | 20 |
| Purdue A | Houston A | 10 | 0 | 0 | 10 |
| Rutgers B | Florida B | 10 | 0 | 0 | 10 |
| Stanford A | Georgia Tech A | 10 | 0 | 10 | 20 |
| Texas A | Chicago C | 10 | 10 | 10 | 30 |
| Toronto A | Minnesota A | 10 | 0 | 10 | 20 |
| UC Berkeley A | Columbia A | 10 | 0 | 10 | 20 |
| UC Berkeley B | Imperial A | 10 | 10 | 10 | 30 |
| Vanderbilt A | Johns Hopkins A | 10 | 0 | 0 | 10 |
| Virginia A | Rutgers A | 10 | 0 | 0 | 10 |
| WUSTL B | Iowa State A | 10 | 0 | 10 | 20 |
| Yale A | Duke A | 10 | 0 | 10 | 20 |