V.Berezinsky MY TEACHER

INFN, Laboratori Nazionali dell Gran Sasso and Institute for Nuclear Research, Moscow.

Georgii Timopheevich Zatsepin is my Teacher. I came to him first as a graduate student of Moscow University. He was a friend of my aunt and she described him as a young handsome man, very talented scientist who has charmed everyone during his recent lecture in the Writer's Club. «He is a real prince» -she kept repeating. Seeing only old university professors whose lectures I at tented (including L.D.Landau who was probably 50 at that time) I expected to meet somebody like James Bond.

Obviously he was not James Bond. He was old (at the time I met him first he was 42). As a physicist he disappointed me too. The only virtue I respected in physics at that time were calculations. He did not need the calculations. He knew the answers. It depressed me. I was doing the long calculations, while this «old man» was writing on the spot the formulae which I was supposed to obtain.

Now I am not surprised that Georgii Timopheevich seemed old to me. Many years later when I was 50, I met in a bus in Singapore an American family with a little girl. I was trying without any success to get acquainted with her. Finally, she released all the information I wanted from her. Her name was Alice, she was from Santa Cruz, California, and she was five years old. She demanded the similar information about myself and I told her that my name is Ben, that I am from Moscow and I am fifty.

-Fifteen? -re-asked she.

-No fifty-

-Ma- addressed she to her mother -How old are you?-

-I am twenty five-

-So, you are fifteen ? -

-No, fifty-

-But it cannot be. People do not live so long!-

Very soon my skepticism towards Georgii Timopheevich has changed for admiration. I admired everything in my teacher. I was speaking with his intonations. I began all my telephone conversations with a long «e-e-e..». I started to wear beret and sharply to take it off my head greeting my girl-friends.

And still I did not fully realized that he was a great man at the great period of his life.

G.T.Zatsepin started neutrino astrophysics. In early sixties:

He organized neutrino laboratory in Lebedev Institute (actually Laboratory of Neutrino Astrophysics).

He initiated the construction of the first in the world underground laboratory for neutrino astrophysics (Baksan).

He suggested (together with G.V.Domogatsky) a method of detection of neutrinos from collapsing stars and started the construction of the first detectors for this aim.

In his laboratory he initiated a problem of searching for all nuclear reactions suitable for solar neutrino detection and within this program V.A.Kuzmin soon discovered the gallium method.

He started building the gallium detector which now operates in the Baksan Observatory.

After pioneering suggestion by M.A.Markov and I.M.Zheleznykh, he performed (together with V.A.Kuzmin and later with L.V.Volkova) the first detailed calculations of atmospheric neutrino spectra.

He discovered (together with V.A.Kuzmin and simultaneously with K.Greisen) the black-body cut off (the GZK-effect), which was understood later as important mechanism for high-energy neutrino production.

Reading this, very incomplete list of GT (Being not very original we call Georgii Timopheevich in our laboratory by two initials of his name; in other laboratories people invented for their bosses more fancy nicknames, like doctor, furer etc.) activity, I am impressed. Do you think people in the sixties were impressed too? Not at all. Physics is developing like a fashion. Fashion for cosmic neutrinos came almost 20 years later. I remember an international symposium in the Lebedev Institute in the end of sixties.

GT gives a talk about detection of neutrinos from Supernovae. I am in the middle of the conference hall. In front of me one physicist asks another: «Does this guy understand what he is talking about? When this Supernova can appear?» The second one, a good physicist with a good name, nods with understanding and asks publicly:

-When a Supernova was observed in our Galaxy last time?-

-Quite recently, just about 300 years ago. But, in fact... -

-No, no, thank you. You already answered my question -

I was surprised seeing what a little effect such attitude had on GT.

-Poor people! They just do not understand. They will.-

I did not meet in my life another person so independent of the collective opinion. However, he had his own model to follow. This model was A.D.Sakharov. I have heard this name from GT very early, when I was a student. GT never referred to the major achievements of A.D.Sakharov in thermonuclear problem. He admired several episodes of naive readiness of A.D.Sakharov to reconsider the widely accepted concepts which in the end appeared to be not more than the truth by repetition. I think that the names of A.D.Sakharov and I.E.Tamm I have heard most often from GT.

I had good luck and happiness of working with GT during all my life. Even working in such fields as current algebra and GUT models I benefited a lot from discussions with GT. But again I recall the old episode of our joint work, when GT surprised me by his fast reaction and by unexpected suggestion:

In the end of sixties I was much impressed by the GZK effect and once I calculated the neutrino flux which accompanies this phenomenon. I came to GT and asked him whether it is possible to detect these neutrinos. He answered immediately:

«They are already detected. They produce the showers observed at E > 3*10¹⁹ eV» .Unfortunatelly, this beautiful hypothesis was not confirmed, but the idea of p gamma-production of high-energy neutrinos and their detection with the help of inclined extensive showers is plausible till now.

G.T.Zatsepin has been actively working in physics during more than fifty years. His achievements are impressive and widely recognized. Probably less visible is a great love of his former students to whom I have a privilege to belong.