ISINN is true to traditions
and committed to the future

Ending. Start at No. 27, No. 29

Corresponding Member of the Russian Academy of Sciences Anatoly Serebrov (PNPI, Gatchina) gave a report "Accurate investigation of neutron decay and the need to expand the Standard Model. Baryon and leptonic asymmetry of the Universe" on the first day of the Conference. Anatoly Serebrov has been participating in the Conference since the first years it has been held.

“Yes, that’s right. We were young, everything was great, as well as today, at the conference. ISINN is surely a very significant conference for neutron physics. It covers many areas, the relevant topic consists of the fundamental properties of a neutron, where the most essential task is to measure the lifetime of a neutron. I should say that a lot came from Dubna - the first ideas that ultracold neutrons (UCN) can be obtained and stored, initiated by Fedor Shapiro and implemented by FLNP employees. This movement with the UCN has captured the whole world, at present, there are many centres where research is underway with them. The main task that attracted everyone was measuring the electric dipole moment of a neutron since it meets principal issues about violation of temporal invariance.

In Gatchina, under V. M. Lobashev, in the mid-1960s, the design of the first neutron source at the WWR‑M reactor started. I graduated from the university in 1969, was engaged in this topic and with great pleasure study it today.

Since there was a reactor with a capacity of 18 MW in Gatchina, it was possible to obtain a greater intensity of UCN and we had to develop a beamline with a good density of UCN and a trap for their storage. Technically, it was not easy to meet these two problems in one technological complex of our Institute. Our grandiose source with a liquid hydrogen moderator in the centre of the reactor core was launched in 1986. The intensity of the neutron flux on it was comparable to the intensity of the ILL High Flux Reactor (Grenoble). For ten years, together with FNLP, we have carried out an experiment on the storage of chemical substances and have achieved the best storage time. Afterwards, the difficult 1990s started, the operation of the liquid hydrogen neutron source had to be stopped in the late 1990s. The PNPI group carried out further experiments in Grenoble. There, in 2005, we got the best and most accurate neutron lifetime result in the world. The most interesting thing is that this result was in complete contradiction with what was written in the magazine “Particle Data Group”, by 6.5 standard deviations. It caused great distrust and at the same time, interest in the result. We proved our case with a new experiment with a UCN magnetic trap and for almost 20 years, our result has been the best. It has recently been confirmed in Los Alamos, measuring 2.5 times more accurately at the UCN in a magnetic trap and thereby, developing our magnetic experiment. The grandiose accuracy of measuring the neutron lifetime - 4 x 10^-4 was achieved. The fact is that theoretically, the neutron lifetime and other coefficients of neutron decay asymmetries are calculated with the same accuracy that means that they can be compared within the framework of the Standard Model and thereby, to test it and to look for deviations from it.

Traditionally, it is believed that new physics is investigated on accelerators, in collisions of particles. Large staffs and great efforts are focused on them. It turns out, to our delight, that it is possible to identify whether there is a deviation or not by the "non‑destructive" technique of alternative measurements. Recently, we have been able to identify a deviation from the Standard Model in the investigation of neutron decay asymmetries by a detailed analysis of neutron decay data. It turned out that one of the neutrino asymmetries in relation to the other differs by 3.7 sigma. It is already significant, so, we carried out an analysis what model it can be explained for, within the Standard it is not explained. Even at the first stages of developing the Standard Model, the left version of the interaction won, in simplified terms, due to the occurrence of only the left vector W‑boson but at the same time, the classics said that there could be an admixture of the right W. We rethought this fairly ancient theoretical model and it turned out that the new is well forgotten old, only it needs to get engaged in. Indeed, within this model, we saw that there is mixing at the level of four percent. And surprisingly, the mass of the right W boson was evident at 300 GeV and it is 2.5 times more than the mass of the Higgs Boson. And in this model, the effect of CP violation, that is, violation of time reversibility, can be explained. It is the process of CP violations that is key in developing the universe. In the left‑right asymmetric model that we propose, slightly changing the well‑known model of the classics, it was only necessary to change the sign of the mixing angle of the right W with the left W depending on the sign of the charge of the W boson itself. This is the key point. Later, it turns out that the nature of CP violations becomes clear but it still needs to be proved experimentally. And from the clarity of the nature of CP violations, estimates are implemented for the baryon asymmetry of the Universe and oddly enough, we get those figures that are already known. The baryon asymmetry of the universe has already been measured.

What is the key task today? Firstly, neutron physics has got to such a level that it becomes responsible for the most relevant tasks of elementary particle physics, for the nature of the CP invariance violation and the far‑reaching consequences of the origin of the Universe. After we have measured the neutron lifetime with great accuracy, experimenters need to make every effort to measure these asymmetries since it is there that we can "feel" the admixture of the right W to the left W. The accuracy of 3.7 sigma is not enough, it takes 5 or more sigma to finally believe in the model. Currently, it is the key task of the experiment in neutron physics. I think this topic will be one of the principal ones at the next conferences. And cooperation between Dubna and Gatchina, of course, will be carried out in the future. Here, on the IBR‑2 reactor, a lot more can be done in pulsed mode. We need to understand whether it is possible to implement an experiment here to measure decay asymmetries - what we are doing now for the PIK reactor. The main thing is that a new task has occurred. When there are creatively passionate groups and you and I have the same fuse as at the beginning of cooperation and even young people have appeared that are our hope and new power, so, everything should work out."

Professor Ho Manh Dung (Centre for Nuclear Technologies, VINATOM, Vietnam) also shared his impressions with Alexander Nezvanov.

Professor Dung, I am very happy to see you in Dubna this year. This is not your first time participating in ISINN. I remember your wonderful talk and report at the last year's Conference in China. What do you think of the Dubna Conference?

"I'm very happy to be here. And you are right: this is my first visit to Dubna and JINR, but not the first ISINN. First of all, I highly appreciate this Conference, since the organizers did everything to hold it uneventfully and very productively. Talking about my impressions of the Conference, I can state the warm and welcoming atmosphere. All participants from different countries and of course, scientists from FLNP are very open, responsive and always ready to help the rest of the participants. I get a lot of inspiration from my colleagues and their reports and in general, the ISINN Conference has left me with a very good experience.

Thank you for your kind words. What do you think about the possibility of establishing effective scientific contacts with other participants within the framework of the Conference topics? I know that cooperation already develops between Inga Zinicovscaia, you and the institutions in Vietnam. Does the Conference serve to strengthen this cooperation?

–Yes, of course. Inga Zinicovscaia is engaged in Neutron Activation Analysis, just like my laboratory and we have long‑standing scientific relations. We jointly publish some papers. Last year, we we were awarded the JINR Award for our joint investigations. We cooperate not only with colleagues from JINR, but also from other countries of the world. Some of them also participate in this Conference. And I hope that after ISINN, we will have the opportunity to strengthen cooperation between Vietnam and JINR, as well as with other countries. We want to send some talented Vietnamese students to Dubna where they can learn from your specialists. And we would also like to share the results of our research with colleagues from JINR in the framework of joint projects. I had some time out of the Conference yesterday and visited FLNP. It turned out that we have common scientific interests and we could cooperate in the future.

What would you advise the Organizing Committee of the Conference and FLNP?

- It is a very interesting question, since the ISINN Conference covers a very wide range of areas. So, if you ask me what area should be added to the subject of the Conference, then, since Vietnam is a small country and we do not have such large facilities as in Russia or China, if you add more applied areas, such as the use of nuclear physics techniques, it would be relevant for small countries. In Vietnam, nuclear medicine is used in many hospitals at present. This area is currently very developed and in demand with us. If you expand the topic, you can include, for example, a section on radiation safety. That would be very helpful for Vietnam. Many technologies are used in this area. We are talking about applied work, not fundamental research or work on nuclear data since fundamental research requires very large facilities and we do not have the ability to construct them. Therefore, we carry out only some fundamental research, focusing on their practical use.

I asked Chairman, Corresponding Member of the Russian Academy of Sciences V. P. Kolotov (V. I. Vernadsky Institute of Geochemistry and Analytical Chemistry) about the first report on the Section "Nuclear Analytical Techniques and Life Sciences": "M. V. Frontasyeva delivered an interesting retrospective-historical report on our Section "Milestones in the history of Neutron Activation Analysis - celebrating the 90th anniversary" in which the history of the development of Neutron Activation Analysis was summarized, starting with the discovery of radioactivity, the basic milestones are shown, what science was done during this time, pioneer work and people who stood at the origins of Neutron Activation Analysis were highlighted. Marina Vladimirovna has done a great job, she has gathered everything together, somewhere found photos. This report should be published on the JINR website or the Laboratory website as it is interesting in itself.

We have long-standing relations with the NAA Sector, since the time of V. M. Nazarov. Marina Vladimirovna and today, her work is continued by Inga Zinicovscaia, they are engaged in a great and interesting job. In fact, unfortunately, it is the only group in Russia that widely works on the NAA. It was stated in the report that there were many centres and a series of meetings on the NAA were held; conferences on the use of nuclear techniques in related fields were held in Tashkent, Tbilisi, Moscow and Dubna, organized by Academician G. N. Flerov and later, by Yu. Ts. Oganessian. Our Institute started to cooperate with G. N. Flerov back in 1959, even earlier, when he still worked at the Laboratory of Measuring Instruments of the Academy of Sciences, where the first investigation on superheavy elements started. Dubna is a "prayed" place where the consolidation of work on activation analysis and the use of nuclear techniques is held. Researchers gathered here regularly, everyone knew each other. So, thanks to Dubna!"

Zikhona Tywabi-Ngeva (Nelson Mandela University, South Africa) is participating in the Conference for the first time:

- Yes, this is my first ISINN Conference. I decided to take part in it mainly because I had a working relationship with FLNP. And it was very important for me to see some of the research that is carried out in the Laboratory. Obviously, coming here, I pursue my own specific scientific goals and objectives, so I am not yet very aware of what research is implemented at the Institute.

Does the Conference help to get a general idea of all research areas?

- Yes, no doubt. I am really impressed by the wide variety of research areas and the expertise within the Institute. I would also like to highlight that material science is very developed here. Thanks to the Conference, I have learned that there are quite a few devices and facilities available for various types of analysis of my materials. Therefore, I am incredibly impressed with both the depth of expertise and the availability of infrastructure for implementing various types of investigations.

Did you manage to find possible ways for new cooperation during the Conference?

- Yes, we exchange contacts and discuss cooperation with other participants. For example, I have already received two proposals for cooperation from colleagues from China. And for me, this is exactly the main goal of the Conference.

How do you think the Conference will be even more productive and successful, especially, in terms of creating effective conditions for communication between people and organizations, finding the use of various techniques in materials science and basic research, as well as developing cooperation between participants?

- I firmly believe that a new generation of researchers is moving towards a more communicative approach in science. By "communicative approach" I mean presenting the results of research in such a way that even an outsider can understand what the purpose of this project is. Therefore, perhaps, we should try to move away from presenting our research only in a strictly scientific format and instead, show how we have moved from theory to practice and what problems we are trying to meet. We need strategies to communicate our results so that even a person who has never worked in our field can clearly understand the impact our research will have on the economies of our countries or on the societies we serve.

The ISINN-32 was attended by two employees of the VINCA Institute of Nuclear Sciences (Belgrade, Serbia). Dushan Topalovich is sharing his impressions, "I am participating in this Conference for the first time and has visited Dubna for the first time. This is a great place, comfortable for scientists. We are very impressed with the organization of the Conference, the Institute itself. I am here not only because I participate in the Conference but because our VINCA Institute is involved in a joint project with FLNP. I also participate in a collaboration with MLIT. Our project ends at the end of 2026 but I think we will start the next one and therefore, I will come to ISINN."

"I'm very happy to be here," Mirian Radenkovic added. “I think the Conference is going well. Many specialists met here to exchange their new knowledge gained in experiments. Participating in ISINN has been very beneficial to us."

Noha Nassar (Cairo University, Egypt) is participating in the Conference not for the first time: "Firstly, I want to thank the organizers for such a wonderful event. Secondly, it is very important for me to meet from time to time with colleagues to exchange information, to discuss new ideas and to open new projects. The scientists that participated in the work of my Section have very good publications that will be useful to me in my work. I am a postgraduate student at Cairo University. We use Neutron Activation Analysis for environmental investigations with biomonitor mosses. In this way, we study the pollution of industrial areas of Egypt, compare the data obtained with indicators in unpolluted places. We also do some statistical analysis to estimate the sources of industrial pollution."

A Letter of Gratitude to the organizers of the Conference was sent by Punit Dabi (Benares Hindu University, Varanasi, India), it says, "I appreciate as a privilege the opportunity to participate in the ISINN Conference. From online registration to arrival in Dubna, the organizers were constantly in touch and provided comprehensive support to all Conference participants. Its programme was compiled very professionally, all reports and poster sessions were held on time. The Conference considered a wide range of relevant topics related to neutron interaction, neutron detection techniques using liquid scintillators and other detector systems, as well as using them in fundamental nuclear physics, nuclear medicine, radiochemistry, Neutron Activation Analysis. Scientific discussions have been very informative and useful for young researchers like me. An interesting excursion and a wonderful picnic were organized.

I wish to highlight good catering during the whole Conference. As a vegetarian, I was particularly excited about enough vegetarian options. In general, participation in the Conference was an outstanding scientific and cultural experience for me. It was a great opportunity to learn from highly qualified specialists and to communicate with participants from different countries. Thanks to ISINN, I have gained valuable information and have expanded my research practice. Sincere thanks to the Organizing Committee of the Conference and to the whole JINR staff for their hospitality and excellent organization. I will look forward to the opportunity to participate in the next events, to visit the Joint Institute again."

Alexander NEZVANOV, Olga TARANTINA, Translated by Tatyana AVDEEVA,
Photos by Elena PUZYNINA and Igor LAPENKO