2. One can obtain very poor, if any, data on this event.
3. Any of these approaches will hold.
4. Гп any event one should bear in mind that the information obtained may be misleading as to the course ofthe reaction.
READING (18A)
• Read the passage below and find the answer for the following question:
Which symmetries, global or local, hold the greatest interest for physicists today and why?
GAUGE THEORIES1
An understanding of how the world is put together requires a theory of how the elementary particles of matter interact with one another. Equrvalently. it requires a theory of the basic forces-of nature. Four such forces have been identified, and until recently a different kind of theory was needed for each of them. Two ofthe forces, gravitation and elcctromagnetism, have an unlimited range; largely for this reason they arc familiar to everyone. They can be felt directly as agencies that push or pull. The remaining forces, which are called simply the weak force and the strongforce, cannot be perceived directly because their influence extends only over a short range, no larger than the radius of an atomic nucleus. The strong force binds together the protons and the neutrons in the nucleus, and in another context it binds together the particles called quarks that are thought to be the constituents of protons and neutrons. The weak force is mainly responsible forthe decay of certain particles.
A long-standing ambition of physicists has been to construct a single master theory that would incorporate all the known forces. One imagines that such a theory would reveal some deep connection between the various forces while accounting for their apparent diversity. Such a unification has not yet been attained, but in recent years some progress may have been made. The weak force and elcctromagnetism can now be understood in the context of a single theory. Although the two forces remain distinct, in the theory they become mathematically intertwined. What may ultimately prove more important, all four forces are now described by means of theories that have the same general form. Thus if physicists have yet to find a single key that fits all the known locks, at least all the needed keys can be cut from the same blank. The theories in this single favored class are formally designated non-Abelian gauge theories with local symmetry. What is meant by this forbidding label is the main topic of this article. For now, it will suffice to note that the theories relate the properties ofthe forces to symmetries of nature.
Gauge theories — градиентные полевые теории, или калибровочные теории поля
• Look through the passage and And English equivalents for the following Russian terms and phrases:
как построен мир; до недавнего времени; не больше чем; в основном, отвечая зд ...; единым ключ, который подходит ко всем замкам; достаточно заметить; согласно тому же принципу; основные силы природы; слабые/сильные взаимодействия
• Answer some more questions about the passage.
1. What is a long-standing ambition of physicists?
2. What do scientists mean by a single master theory and why is it needed?