Fundamental particles

The study of processes which take place in times so short and within regions of space so small that they are almost inconceivable in 'everyday' terms has been responsible for the development of techniques and commodities that are taken for granted in •industrialized countries.

Television, fluorescent lighting, X-rays, photoelectric cells, nuclear power stations, lasers and many other discoveries all became possible as scientists began to understand the laws of motion of minute entitiesthe fundamental or elementary particles-travelling at nearly 186,000 miles an hour, the speed of light, in a vacuum. Grasped At the turn of the century science was clearly on the brink of major developments. Cathode rays, photoelectricity, radioactivity and X-rays were new phenomena which could not be explained by the old theories. Newton's laws of gravitation and particle motion, which for 250 years had provided the theoretical basis for bourgeois science now proved inadequate.

The mechanical materialists who believed that Newton had said the last word and that the richness of the objective world could be reduced to a few fixed building blocks and exhausted by a set of simple equations gasped like a fish out of water.

As late as 1897, Lord Kelvin, a giant in the world of physics in the latter part of the 19th century, still wrote that the idea that 'electricity is a continuous homogeneous liquid' (rather than having an atomic structure) deserved careful consideration.

The brilliant achievements of the classical mechanics of Newton and the Faraday-Maxwell theory of electromagnetism, elaborated in the 19th century, brought to a close the era of classical microscopic physics.

These theories were now seen not as eternal truths, but valid within well-defined limits that man had discovered in his struggle to conquer nature and grasp objective reality. New qualities Provided we deal with dislances greater than the atomic radius (one hundred millionth of a centimetre) and speeds far less than that of light, classical physics suffices.

Outside of these bounds new qualities emerge and new laws have to be formulated to encompass them.

The development of quantum theory brought with it fierce theoretical conflict. What light did it throw on the nature of objective reality?

Conclusions

The orthodox reply which gained dominance during the 1920s represented a retreat into the marsh of subjective idealism.

The main conclusions can be summarised as follows:

(a) The object of the theory is not to describe the behaviour of things but to build up a mechanism which gives the results of experiments.

(b) Outside measurement no knowledge is possible.

The conclusion is reached that it is meaningless to talk about an objectively existing world at all.

All we can be sure of is a number on a dial when an experiment is performed.

Lenin in 'Materialism and Empirio-Criticism' (1908) mercilessly attacked Bogdanov and others in the Bolshevik Party who were embracing the same idealistic position in the perio of reaction following the defeat of the 1905 revolution.

He called them 'god-seekers', the do form ence аOOI some outsiae force always beyond man's grasp. Symposium Inevitably, the theoretical battle over quantum theory reduced itself to materialism versus idealism with the idealists performing many of the classic contortions.

Here is an extract from a discussion held at Bristol University in 1957 as part of a symposium on observation and interpretation in the philosophy of physics.

'Vigier: ... I do not think that things which exist are things which might have been observed. This is where the split comes in a very clear form.

'Rosenfeld: I don't say that. Don't continue on that line because I do not say that things only exist in so far as they could be observed. All the statements we make about the world are necessarily desAT FIRST sight more success appears to have been achieved by the Robbins Report on Higher Education.

'Vigier: Let us say then we agree that the world exists outside any observer. Did the laws of quantum mechanics apply to the world at a time when there were no observers present?

'Rosenfeld: Of course.

'Vigier: O.K. If you say then, that the laws of quantum mechanics did apply at that time, then the laws of quantum mechanics are real, objective, statistical laws of nature, which have nothing to do with the observer, and are verified whether there are observers or not.

'Rosenfeld: No.' Here we see the contradiction into which the idealist is led.

Not last word Professor Rosenfeld swallows it whole-in 1908 the idealists attempted to resolve it by introducing various fictitious 'observers' to make sure that the world didn't disappear before man arrived on the scene!

Today, few physicists will insist the the present quantum In order to fit in with the the atom.

Or was it?

This situation has arisen increasingly with the probing oi nuclear interactions.

The years around 1930 saw the birth of the era of nuclear physics.

The basic instrument for 'smashing the atom', the cyclotron or particle accelerator, was developed in the period by E. O. Lawrence at California University. This was the big step necessary to break down the nuclear barrier.

The construction since that period of bigger and more powerful machines has produced literally scores of new particles whose masses get progressively larger as increased energy provides the possibility for the creation of mass.

Most of the particles are extremely shortlived and disintegrate in a period of time of the order of one ten-thousand-millionth of a second. The stable particles are the electron, . proton, neutrino, antineutrino, positron and photon while the neutron is relatively stable with a lifetime of about 16 minutes.

rules around 100,000 electron volts. sub- In 1960, a 30,000 million make volt (30 GeV) accelerator was !!). completed at the Brookhaven in in- laboratory in the United States ng of that measured about a-mile in circumference. ) saw British nuclear physicists ıclear are laying foundations for a new design of 'atom smasher' that could be much smaller : for and yet far more powerful :yclo- than anything seriously envisrator, aged so far. od by A preliminary. study has fornia been made by the Science Ree big search Council's Rutherford down Lo replace of he rip of large : that electromagnets on Nimrod, its more 7-GeV machine, with a ring of • PrO- superconducting magnets new the same diameter. t pro- In this way its power could eased be raised fourfold, to the same ibility order as the accelerator at the European Commission for Nuclear Research (CERN) in I dis- Switzerland. s are Such a project could be a time pilot experiment for a much thou- more powerful machine of percond. haps 1,000 GeV. trino, If present plans for a 300and GeV accelerator for Europe on is break down-and France now threatens to follow Britain in etime withdrawing from participation in the £78 million machine Europe's physicists may replan their objective on a longer timescale but far more ambitiously. ence's This will probably do them ergies little good in the light of the economic crisis.

Cannot predict The 1,000-GeV machine will cost over £100 million and it is virtually impossible to predict what it will produce when it begins to operate-just a profusion of even bigger particles or will some quantitative change take place which will provide the key to the presen igsaw puzzzle!

Of one thing we can be certain.

The future unification of nuclear theory and its incorporation into a more comprehensive theory of fundamental particles will reveal it to be a more or less accurate reflection in men's minds of objective nents re of processes—not God playing dice.