Special issue. Rochester Conference in Dubna. 1964

Beginning of the special issue in No. 29-30 of 1 August

"For Communism", No. 65, 1964

At the plenary sessions

The XII International Conference on High Energy Physics has moved on to a new, main stage of its work. Plenary sessions have started.

The first day of plenary sessions was dedicated to theoretical and experimental investigations of interactions of nuclear particles - pions and nucleons at high energies.

The sessions were chaired by famous scientists, the mere listing of whose names shows the high level of the Conference, the great importance that the world scientific community attaches to its work. Today, at the chairman's console were: German scientist G.A.Bethe, whose name has forever entered the history of nuclear physics, the outstanding American experimenter Edwin McMillan, Soviet scientist Academician N.N.Bogolyubov, the founder of a large team of theoretical physicists, American physicist M.L.Goldberger and the outstanding English scientist R.E.Peierls.

According to the tradition that has developed at high energy physics conferences, physicists, each of whom is one of the most prominent in their field, give reports at plenary sessions. They summarize all the most significant investigations in this area, regardless of the country in which these investigations were carried out.

The first to speak at the plenary session was Doctor of Physical and Mathematical Sciences Yu.M.Kazarinov (Dubna). He analyzed the results of investigations of nucleon interactions at energies up to 1 billion electron volts, carried out in Dubna, the USA, France and England. The most detailed were the investigations of Dubna and the USA. They were carried out using different techniques. However, the discussion showed that there were discrepancies only in one parameter out of twenty. Thus, new and most detailed information on nuclear forces entered the arsenal of science. The report of S.Lindenbaum (USA) contained the results of precise measurements of the characteristics of nuclear interactions. The investigations were carried out at those energies that are maximally achievable in the currently operating powerful accelerators of charged particles. The accuracy of these measurements has increased significantly since the last conference.

Professor A.A.Logunov (USSR) gave a report on the conclusions from modern field theory for the experimental research of particle interactions at the highest energies. Academician I.Ya.Pomeranchuk's well-known investigations were developed into a coherent section of theoretical physics by the efforts of Soviet scientists. The young Soviet scientist, Corresponding Member of the USSR Academy of Sciences D.V.Shirkov and Professor E.L.Feinberg gave a detailed theoretical justification for the research of nuclear particles in a wide spectrum of high energies.

Causality in the microworld

The principle of causality has entered our everyday life. Everyone knows for sure that the cause comes before the effect. But is the principle of causality preserved, that is, the sequence of events in space and time on the ultra-small space-time scales in which the physical processes characteristic of the microworld are played out? This issue is the subject of theoretical research presented at the conference by Professor D.I.Blokhintsev and G. I. Kolerov (Dubna).

If the conditions of the microworld are characterized by deviations from the principle of causality, then it should immediately manifest itself in the so-called dispersion relations (one of the powerful mathematical techniques used in theoretical physics). The authors found the values of those energies at which changes in the dispersion relations could become noticeable. Currently, experimenters approach the possibility of testing the dispersion relations and therefore, the principle of causality at high energies. D.I.Blokhintsev also proposed a specific experiment to test the idea of the homogeneity of space and time. This experiment will soon become possible with the help of new accelerators constructed in the USSR and the USA.

Strange behavior of strange particles

The Great Hall of the Joint Institute for Nuclear Research, where experimental physicists delivered reports on their investigations, was filled to capacity when the session of the strange particles section started. (This is the name of a group of particles distinguished by some special properties.) American physicists J.Cronin and V.Fitch reported on experiments carried out at Princeton University. In these experiments, scientists observed for the first time the decay of one of the so-called strange particles - the K-0-2 meson into two ? mesons. It would seem that there is nothing unusual about this. After all, other types of decay of K 0-2 mesons are already known. But the whole point is that from the point of view of modern theory, the very particular decay of this particle is impossible (as theorists say - forbidden).

If the experimenters were not mistaken, then they apparently encountered a very important case of violation of the symmetry of the microworld, similar to what happened in 1956, when the seemingly unshakable law of conservation of parity was overthrown.

The reports of Cronin and Fitch caused a lively discussion. Some of the speakers tried to find possible sources of errors. The dispute will be resolved by future control experiments that are currently prepared in laboratories around the world. If the Princeton results are confirmed, it will result in a significant change in physicists' understanding of the nature of the decay of strange particles.

An interesting report was given at the strange particles section by E.O.Okonov, a researcher at the Joint Institute for Nuclear Research (USSR). Together with other Dubna scientists Dumitru Neagu (Romania), N.I.Petrov, V.A.Rusakov (USSR) and W.Tsun-fan (China), he implemented a range of experiments to establish whether there is an antigravity effect between particles and antiparticles in an inclined beam of the same K-0-2 mesons (one of the manifestations of gravity is terrestrial gravity. Scientists were looking for the opposite effect in their experiments). Both positive and negative information are valuable for science. It is important to know the truth. The experiments carried out in Dubna gave a negative answer. Antigravity between particles and antiparticles in a beam of K-0-2 mesons is absent. Another "blank spot" in the knowledge of scientists has been erased.

Scientists' rest

On Sunday, 9 August, the Conference had a break. The delegates took a boat trip along the Volga and the Moscow Sea. Many of the participants of this trip were visiting the USSR for the first time. But even for those who had already been to our country, it was very interesting to visit the great Russian river.

"For Communism", No. 65, 1964

New ideas of theorists

One after another, the sessions of numerous sections of the Conference replace each other, attracting special attention of scientists. The section of new ideas attracted special interest.

Scientists from thirty countries filled the Conference hall of the Laboratory of Theoretical Physics. Here, demanding criticism reigned. The most prominent theorists of the world spoke smoothly about the imperfection of modern theory. It still does not explain much, many issues are still left unanswered and some of the answers sometimes result in even more incomprehensible solutions. One of such cases was dedicated to the report of Academician I.E.Tamm (USSR).

"For many years now," he said, "the scourge of quantum field theory has been the so-called ultraviolet divergences. This phenomenon boils down to the following: when calculating certain physical quantities (for example, mass, charge, scattering amplitude), satisfactory answers are obtained in the first approximation. But when trying to make refinements to this result, absurd calculation results are inevitable: infinitely large quantities. It means that it is necessary to develop a theory in which divergences would not arise at any stage of the calculations."

Academician I.E.Tamm proposed a new geometric technique based on the idea of discreteness (discontinuity) of space and time. The use of this technique in developing field theory promises to free scientists from the nightmare of ultraviolet divergences.

Another way out in the fight against the same difficulties was proposed by Soviet scientists B.A.Arbuzov, A.T.Filippov and O.A.Khrustalev.

If Academician I.E.Tamm explained the impossibility of precise calculation of physical quantities using the imperfection of modern concepts of physicists, then B.A.Arbuzov and his colleagues brought to the forefront the assumption about the imperfection of the calculation techniques used by scientists. They developed a new technique of calculating physical quantities that according to many scientists, is very promising and encouraging. Their research echoes the intuitive considerations previously expressed by the famous Chinese scientist working in the USA, Nobel Prize winner Li.

Is the principle of causality comprehensive?

The American scientists S.Lindenbaum and T.F.Kaysia gave reports. They carried out extremely precise and ingenious experiments, the purpose of which was to find out whether the principle of causality is valid on incredibly small scales, characteristic of the world of elementary particles. According to the scientists, the fate of an entire area in modern theoretical physics, the technique of dispersion relations, depended on addressing this issue.

The American scientists succeeded to advance in their experiments to very small quantities, characterized by a fraction of a centimeter, designated by a fraction with fourteen zeros after the decimal point (about five hundred-thousandths of a hundred-billionth of a centimeter). But even with such almost unimaginable precision, as the speakers claimed, they were able to establish that the principle of causality invariably applies.

A bold assumption of a young scientist

The report of Candidate of Physical and Mathematical Sciences V.G.Kadyshevsky (Dubna) was distinguished by great boldness and originality of ideas. Developing the ideas of Academician I.E.Tamm, he interpreted discontinuous space and time as a field consisting of some new neutral particles. Investigation of their interaction with "ordinary" particles, such as electrons, protons, mesons, will help to better understand the structure of matter.

But do the new particles that V.G.Kadyshevsky speaks of occur? Future experiments will answer this question. They should be carried out at ultra-high energies and extremely high precision.

Scientists of the world work together

The family of resonances expands

On 11 August, the International Conference on High Energy Physics was held. Two sessions in the first half of the day were dedicated to resonances of elementary particles. Resonances are states that resemble short-lived and rapidly decaying particles. They have been discovered in recent years and are currently studied at virtually all powerful accelerators in the world. Hundreds of articles in scientific journals are dedicated to them, since the research of resonances is of great significance for understanding matter.

At the first plenary session, chaired by Academician A.I.Alikhanov, Professor S.Ya.Nikitin (Moscow) gave a review report. His report was supplemented by Professor R.Armentores (Geneva) that spoke at the second plenary session, chaired by Sulamith Goldhaber (USA).

Both reports contained a presentation of the latest results of the investigations of scientists, institutes and laboratories of the USSR, USA, England, France, the GDR, Germany, Italy, Poland, Hungary, Romania, Yugoslavia, as well as two large international centres in Dubna and Geneva. When brought together, they helped to better present the overall picture of this important scientific area.

The two years that have passed since the previous conference on high energy physics are characterized by a significant increase in the accuracy of experimental data. To a large extent, it is due to the improvement of experimental techniques and the machines that automatically implement part of the work previously carried out by scientists. As a result of the accumulation of new and accurate data, some properties of resonances that were previously only guessed came out more clearly. New resonance states have been discovered. It is characteristic that more and more data concern the so-called many-particle resonances, that is, those when this very short-lived particle decays not into two, but into three or more relatively sustained, resistant particles.

The third plenary session, chaired by B.Gregory (Geneva), was dedicated to the investigation of so-called "strange" particles, so named due to some of their special properties. American scientist D.Miller (Berkeley, California) reported on recent measurements that significantly refined the data on the masses of "strange" particles. New data on the electromagnetic properties of hyperons were also of great interest. They are especially valuable concerning new theoretical concepts on the nature of interactions between particles.

A special session was dedicated to a review of new research by theoreticians in this area, on which Abus Salam (Pakistan) made a very interesting report, chaired by Julian Schwinger (Harvard, USA).

The structure of the particles that make up the atomic nucleus has been studied for many years using powerful electron accelerators. American physicist Norman Ramsay spoke at the evening plenary session of the Conference with a review of the latest research results in this area. He spoke about the research carried out in the USSR, USA and France. The session was chaired by Nobel Prize winner R. Hofstadter.

A Day of intense work

12 August was a day of extensive plenary sessions at the Conference. The first of them started under the chairmanship of L. Schiff (Stanford, USA). Doctor of Physical and Mathematical Sciences A.M.Baldin summarized the theoretical research in the field of electromagnetic interactions of elementary particles in his report presented at the Conference.

Dawn of Neutrino Physics

Neutrino Physics. This fascinating area was the subject of the next plenary session. It probably attracted the largest number of participants. All the seats in the hall were occupied. Many stood and sat on the steps in the aisle. Academician B.M.Pontecorvo, one of the leading neutrino researchers, chaired the session. The Italian physicist Gilberto Bernardini gave a summary report.

Currently, experiments with neutrinos at powerful particle accelerators are implemented by two laboratories. They started in Brookhaven. But at the Conference in Dubna, mainly experimental results obtained at CERN were reported. There, scientists achieved the greatest success. They repeated the experiment proposed by Bruno Pontecorvo, but carried it out at a higher level, on a larger scale. At present, the conclusion about the occurrence of two neutrinos has been even more reliably proven.

Evseev's experience cracks the theory

Experimental data on weak interactions involving ordinary particles were presented by A.I.Mukhin in his report at the third plenary meeting, chaired by CERN Director General Victor Weiskopf.

A.I.Mukhin spoke about experiments carried out at CERN, in which the lifetime of the mu meson was measured with great accuracy. It allowed to more reliably test the conclusions of the universal theory of weak interactions.

The same report on a very interesting experiment implemented at the Laboratory of Nuclear Problems of the Joint Institute was presented by V.S.Evseev. The fact is that this experiment, dedicated to the investigation of the angular distribution of neutrons during the capture of mu-mesons using nuclei, sharply contradicted the conclusions of the theory. At the same time, the totality of practically all other experimental data on weak interactions of elementary particles is in exact agreement with the theory. This experiment, carried out in 1963 and then re-tested once again, makes not only experimenters, but also theorists think. Now Evseev's experiment is repeated by researchers in the USA.

A very delicate experiment was carried out at ITEP by Yu.G.Abov. While studying the capture of slow neutrons by nuclei, he succeeded in discovering the effect of parity non-conservation in weak interactions on nuclear forces. These additional forces, or "add-ons", amounted to ten-millionths of the main nuclear forces. Nevertheless, the "add-ons" were measurable.

Mainstream news of the Conference

In Dubna, focus is on the investigation of weak interactions involving strange particles. Obviously, this is why the plenary session dedicated to this topic was chaired by Corresponding Member of the Academy of Sciences of the USSR M.A.Markov and the report on the main experimental data was made by Doctor of Physical and Mathematical Sciences I.V.Chuvilo. Both of them are employees of JINR.

The current year is characterized by a very large number of investigations carried out in this area in different countries of the world. The abundance of experimental data allowed to establish the general patterns of decay of unstable particles with great accuracy. Particularly interesting were the experiments on the research of decays of neutral K-mesons. Many consider them the mainstream news at the Dubna Conference.

The penultimate plenary session of this day was chaired by G. Bright from Yale University (USA). The theoretical situation in the field of physics of weak interactions was reported by the American scientist S.B.Treiman.

XIII Conference will be held in Berkeley

Already at the end of the day, the final plenary session was held, summing up the Conference activities in the field of high energy physics. (There were still two days of work ahead, dedicated to the experimental methodology).

At the final session, Chairman of the Conference Organizing Committee Professor D.I.Blokhintsev spoke.

On behalf of foreign physicists, the floor was given to the famous American scientist Robert Marshak that was one of the founders of the Rochester conferences. He expressed gratitude to the Organizing Committee for the good organization of the Conference and to the participants - for the great and successful work they had carried out. R. Marshak reported that the XIII International Conference on High Energy Physics will be held in two years in Berkeley.

M. LEBEDENKO

Press conference of scientists

After the final plenary session of the first part of the XII International Conference on High Energy Physics, chaired by Corresponding Member of the Academy of Sciences of the USSR D. I. Blokhintsev, a press conference was held for Soviet and foreign journalists. The participants of the Conference answered a number of questions from newspaper and news agency correspondents.

"For Communism", No. 66, 1964.

On the eve of new discoveries

On 12 August, the plenary sessions of the Conference ended. The discussion of all physical issues submitted for consideration to the Conference was completed.

Chairman of the Conference Organizing Committee, Corresponding Member of the USSR Academy of Sciences D.I.Blokhintsev spoke at the final session. Below we publish excerpts from this speech.

"Several hundred reports were presented at this Conference," D.I.Blokhintsev said. "The rapporters managed to compact them about three times. (The rapporters at the Conference were well-known Soviet and foreign scientists that gave overview reports on certain scientific areas - Ed.). I would have to compress them several dozen times more. At such a degree of compression, the matter would go into a state that is still little studied in physics. Therefore, it is more natural to choose a different path and dwell only on those facts and ideas that can be especially significant for the further development of high energy physics. Of course, with such a choice it is difficult to avoid personal coloring and one involuntarily remembers that prophets and soothsayers are stoned. Nevertheless, this is the traditional function of the chairman of the conference and whatever the risk, I must fulfill it.

We all clearly understand that in the few years of development of research in high energy physics, a picture of a completely new world has appeared before us - the world of elementary particles. Armed with principles that may be outdated, or in any case do not have sufficient strength, we struggle to find the truth through the accumulation of a huge number of facts. These facts sometimes form beautiful and tempting combinations that can serve as a basis for theoretical constructions. Most of them turn out to be ephemeral. Therefore, many physicists, not without reason, believe that the key to understanding the laws of the microworld will be found only as a result of revolutionary changes in the most basic principles of modern theory. Perhaps, it was precisely this line of thought that aroused significant interest in the section of "New ideas" that would be more correctly called the section of "Heretical ideas". At this section, the assumptions looming before the imagination of theorists about the quantization of space-time, the possibility of changes in causality on a small scale, or the special role of the nonlinearity of strong fields near particles were reported. The success and validity of these concepts are very small and I would like to emphasize once again that the interest in them, in my opinion, was not so much a consequence of success in these areas, but rather of the fact that many people apparently became thoroughly bored with the old principles. However, these old principles may be weak, but they are stable and there are no direct indications from experiments of their inconsistency.

In this regard, it will be convenient for me to turn to the results that were reported and discussed at the Conference in the field of strong interactions of elementary particles. The measurement of the scattering of nucleons and ?-mesons at small angles and the proof of the occurrence of scattering amplitude at high energies are essentially new.

Together with very precise measurements of total cross sections, these data allowed to begin testing the dispersion relations in the high energy area.

An extensive set of new asymptotic relations not only for total cross sections but also for differential ones was presented at this Conference. This set opens up broad possibilities for experimental verification of asymptotic relations. Verification will also be of fundamental importance, since these relations are based again on the assumption that causality in the microworld has the same form as in the macroworld.

A number of papers have been dedicated to measurements of PN and NN scattering, including large scattering angles. Interpretation of these results, apparently, today cannot be made without the use of model approximation, for example, the optical model, in the substantiation of which there has now been some progress. For the interpretation of inelastic processes, the use of the picture of single-particle exchange, based on the elementary division of collisions into peripheral and central ones, has proven to be more resistant to the test of time than one might think. There has also been some success in the development of the statistical method. It is especially interesting to note that the concept of fireballs receives various confirmations from the analysis of data on inelastic collisions at extremely high energies.

At the last conference, many saw the dawn of a new theory in the method of complex moments. These hopes did not come true. However, the Regge pole method itself, along with other modeling techniques, has firmly entered the practice of theorists and can be very useful in cases where a process can be described by a single pole.

Two years ago, it became clear that the world of microparticles had been replenished with new objects - resonances. A large family of these ephemeral particles is currently known, the mere listing of which was already a serious difficulty for rapporteurs. At sessions and seminars, there were many discussions about which of the discovered resonances should be considered firmly established and that were still subject to verification. Apparently, experimenters should establish a gentleman's agreement among themselves regarding the rules for including statistical outliers in the respectable category of resonances. It would be impossible to describe the entire situation in a short summary. Many new resonances were discovered. Some resonances were "closed", such as ABC. (The ABC resonance is named after the American scientists that "discovered" it: Abashyan, Buts and Crow. Two years ago, at a conference in Geneva, the investigations of the groups of V.M.Sidorov, G.I.Selivanov and L.M.Soroko were reported, showing that the conclusions about the occurrence of the ABC resonance were erroneous, although the actual data of the experimenters are not disputed. It was later confirmed by experiments implemented at CERN and the USA. - Ed.).

However, the biggest event at this conference was the announcement of the establishment of order in the diversity of elementary particles and resonances that had recently seemed to border on chaos. I mean the discovery of the significance of the symmetry group C-U^-3 for the systematics of particles and resonances."

In this section of his speech, D.I.Blokhintsev noted that scientists had found very simple patterns that linked related particles. It allowed to calculate the masses of particles with an accuracy of five percent, as well as to predict the occurrence of individual particles. In particular, the prediction of the occurrence of the omega-minus hyperon was confirmed experimentally.

Having pointed out a number of other investigations of great importance, D.I.Blokhintsev moved on to the issue of research of weak interactions.

"The research of weak interactions," he said, "constantly yields exciting results. This time, the attention of the Conference participants was particularly attracted by a paper in which the decay of the K-0-2 meson into two ? mesons was discovered. As far as I can judge, the experiment itself is beyond doubt and if its interpretation is confirmed, a most serious theoretical problem will arise. The most direct understanding of this experiment would mean recognizing the non-conservation of combined parity and therefore, the irreversibility of elementary phenomena. The consequences of such a course of events could be very far-reaching. In this regard, it may be appropriate to note the experiments on the capture of mu mesons in the nuclei of Ka and Es that indicate a degree of asymmetry in neutron emission giving rise to concern about the validity of the generally accepted theory of weak interactions.

Among the interesting and important facts reported at this conference is the proof of the occurrence of a potential for nuclear interaction that does not conserve parity. Thus, weak interactions are detected in the interaction of nucleons.

The quantitative research of weak interactions has also advanced considerably.

Further research with neutrino beams has resulted in further and more thorough confirmation of the occurrence of two types of neutrinos (muonic and electron). Finally, it should be noted that the search for the intermediate W-boson that has been a great effort, has resulted in the conclusion that such a boson does not occur in the mass range of less than 1.6 GeV. (The initial conclusion about the occurrence of this boson was put forward at CERN. Careful experiments were also carried out there, on the basis of which the conclusion has been made about the lack of an intermediate boson - Ed.).

Therefore, those insisting to carry out further search will face not so much a scientific problem as a problem of diplomatic physics: convincing their country's "atomic committee" of the need to construct more powerful accelerators than the operating ones. However, I think we are all convinced that such accelerators need to be constructed and not only for the sake of searching for the W boson.

I am also convinced that we are standing on the threshold of a profound scientific revolution that, as has always happened before, will entail a new era in technology and in the life of mankind.

Moreover, the results of this conference, it seems to me, emphasize that we are not so far from our common goal - the discovery of new principles of the theory of elementary particles that govern the world. Of course, skeptics and there are always some, may say: "Yes, you are probably right and we are very close to the goal, if only we are going in the right direction…"

I have come to the end of my review and I fully understand that it is far from perfect. Following the emerging tradition, I have not mentioned any names, laboratories, or even countries in which this or that research has been carried out. Let the consciousness of that high spirit of collectivism that starts to develop in modern science replace petty vanity. Incidentally, it will strengthen the hope of humanity for the possibility of a better future."

For Communism, No. 66, 1964.

Trip to the state farm

American scientists, participants of the XII International Conference on High Energy Physics in Dubna, Stanford University professors R.Hofstadter and H.Anderson made a trip to the specialized vegetable and dairy state farm "Yakhromsky". The guests were accompanied by Administrative director of the United Institute V.N.Sergienko. On the way, a conversation started. The guests were interested in the history of how Dubna had been founded, construction in the city and at the Institute, as well as the administrative affairs of the Institute. V.N.Sergienko gave exhaustive answers to all questions.

The American scientists were met by the chief agronomist of the farm N.M.Makanov and other workers of the state farm. Nikolay Mikhailovich spoke about the specialization of the farm, the amount of commercial products produced, the amount of profit and the number of workers in the state farm.

The guests were interested in whether this farm was average or advanced.

"Our farm is average," N.M.Makanov says, "and next to us there are two specialized farms "Mayak" and "Bolshevik" that we have been trying to catch up with for several years now, but so far, we have not succeeded."

American scientists in the fields of the state farm ask a question about how the directors of the state farm are going to increase the productivity of the farm.

"We have everything for it," N.M.Makanov answers, "by increasing the use of fertilizers and herbicides, we intend to increase the productivity of milk and vegetables in the coming years by two or three times. Scientists from the USA inspected the houses of the workers of the state farm, the new school and the agricultural technical school under construction."

Professors R.Hovshtadter and H.Anderson warmly thanked Administrative Director of JINR V.N.Sergienko for organizing an interesting trip.

V. DYACHKOV, FLNR employee

For Communism, No. 66, 1964