 ora ditemi la verità no cioè non avevo un compito semplice perché io parlo dopo Steve Noken e introduco adesso un premio Nobel no cioè è come cantare un grande concerto tra Bruce Springsteen e Bruce Springsteen cioè io sono il cantante locale no che canticchia tre canzoni ok fine della storia bene vi voglio introdurre al primo grande ospite di questa sera che il professor Takaki Kajita Takaki Kajita è stato insegnato del premio Nobel per la fisica nel 2015 insieme ad Arthur McDonald perché ha rivelato un fenomeno che si chiama oscillazione dei neutrini e rivelando l'oscillazione dei neutrini ha dimostrato che i neutrini hanno una massa ora i neutrini sono besti particolari è come se immaginatevi l'uomo di neanderthal l'uomo sapiens e l'uomo erectus ok sono tre specie diverse di un'unica famiglia la famiglia degli ominidi solo che omo sapiens e omo sapiens e l'uomo di neanderthal e l'uomo di neanderthal e l'uomo erectus e l'uomo erectus i neutrini no anche loro sono in tre famiglie diverse ma mutano fra loro sono in un certo senso uno e trino e questo mi ricorda qualcosa io volevo chiamare sul palco takaki kajita per l'entrazione e good evening well as the first talk on the messengers of the universe I'm going to talk about neutrinos now to begin this talk I want to show this slide and this is a diary written by Fujiwara teika and well actually this is about one thousand years ago and in one of the pages he wrote down some very spectacular event that occurred in the universe well to be honest I cannot read but anyway according to the people who can read the yellow part is the description of the very bright new star that emerged on May 1st 1006 and the green part is another description of a bright new star that happened in May 1,054 so clearly these descriptions tells us that people have interested in the events that occurred in the universe and well in the present day word these very bright new stars are supernova now because I'm going to talk about neutrinos and I want to talk about a little bit about the key features of neutrinos first neutrinos are fundamental particles like electrons and quarks and well of course you want to know a little bit more then neutrinos are something like electrons without electric charge in fact this feature has a very special consequence neutrinos can easily pass through even the art or even the even the sun so neutrinos can easily pass through stars and in fact this feature is very important because neutrinos can bring information of the fundamental processes at the center of the stars so because of this feature we think neutrinos are one of the key players in the multi messenger astronomy okay now I want to show you the neutrino detector and this is the cameo kanda experiment and this experiment was operated in the 1980s and 1990s and this is a large water detector located deep in underground and in fact this detector contained 3000 tons of very pure water and I want to show you another example this is another large water detector called IMB and this was actually bigger than cameo kanda it had 8000 tons of pure water inside this detector again this detector was located deep underground in united states by the way these detectors were constructed to observe proton decays not to observe neutrinos in fact in the 1970s new theories emerged and these theories predicted that protons should decay with the lifetime of about 10 to 30 years well 10 to 30 years is an extremely long lifetime well if protons do not decay or do decay our daily life doesn't change but scientifically this prediction was extremely important and therefore people constructed these kinds of detectors to observe proton decays unfortunately proton lifetime was longer than predicted so these experiments never observed proton decays however a lucky thing happened well let me tell you and this is the explanation of the life of the stars stars like this our sun the total life of the sun is about 10 bilion years and if the mass of the star is smaller than the sun then these are sorry these stars have a extremely long lifetime but if the mass of the star is happier than the sun then these stars have a dramatic life they have shorter lifetime but at the end of the year lifetime they have the very significant explosion this is called the supernova and after the supernova typically neutron star is generated or the mass of the star is much heavier than the sun then the life is even shorter and they have the supernova and at the end maybe black hole is formed so this was the thought I would say people expected that supernova was the event that occurred at the end of the life of a heavy star but we didn't have proof now in 1987 in February um there was a very bright new star observed in large magianic cloud that is the nearby galaxy next to our milky way galaxy so this star exploded and after the explosion the star was like that so this was the supernova explosion and as I said at that time two proton decay experiments cameo candy and imb were in operation by the way I have to say according to the theory of supernova explosion 10 to 58 neutrinos should be emitted in about 10 seconds this is really a huge number huge number of neutrinos should be omitted in 10 in 10 seconds therefore the neutrino detectors on the earth could observe these neutrinos and in fact the imb experiment and cameo candy experiment and furthermore the Russian bachstein experiment observed neutrinos related to the supernova explosion and with with these detectors a total of about 20 neutrinos were observed only 20 however these 20 neutrinos were enough to prove the basic understanding of the mechanism of the supernova explosion so we understood that supernova occurs at the end of the heavy star's life at the end of the heavy star's life all of the fusion processes finish and then the star collapse and then at the center of the star neutron star is formed and then all the materials are bounced and this way the supernova explosion occurs so we had only 20 events but this was really enough to understand the basic mechanism of the supernova explosion and because of this observation professor Koshiba the safety and overall presence in physics in 2002 by the way he was my thesis advisor so actually we are very happy to hear this news well I wanted to show you a video but unfortunately we have some trouble therefore I cannot show you the video but with this video I wanted to tell you the activities of the people who would like to reproduce the supernova explosion actually in the 1980s people thought that people they are able to reproduce the supernova explosion by the computer simulation by the way you know the sun and you know that the sun is a very good ball or a very good spherical shape therefore initially people thought that they can reproduce the supernova explosion by a computer simulation assuming the complete spherical symmetry complete ball however they were unable to reproduce or simulate the supernova explosion therefore in recent years people try to simulate the supernova explosion by a full three dimensional simulation and in fact this video wanted to show you the result of the full three dimensional simulation and in fact well this would show you how complicated the supernova explosion is but anyway I have to give up anyway because of the so dramatic observation of the supernova neutrino detection we had the next generation neutrino detector it is super cameo cande it is a 50,000 water detector so this is approximately one orders of magnitude bigger than the previous generation detectors and well in fact this detector is famous because of their discovery of the neutrino oscillations that shows that new neutrinos have small mass but unfortunately today we are talking about the messengers of the universe so I'm going to stick on the supernova neutrinos by the way this is another view of the super cameo cande detector here we take a photo from the top of the detector viewing the the downward and you can see the water and we have been waiting waiting waiting for the next supernova explosion well we have been waiting for more than 20 years but unfortunately super cameo cande so far was unable to observe supernova neutrino events so finally people decided to show you how the supernova neutrino detection could look like in super cameo cande so in this case I hope yeah so this is the detector now super neutrinos will be arriving in one second so this is the signal we would expect for a supernova explosion and in about 10 second all the neutrinos gone so this is the signal we would expect for the supernova explosion and in fact the real signal should be even more dramatic because super cameo cande will detect about 10,000 neutrino events in 10 seconds so this would be really fantastic information to know the detail of the supernova explosion so super cameo cande is still waiting for the next supernova explosion by the way we are now in the multi messenger astronomy era and now in addition to neutrinos we have gravitational wave detectors and we are going to hear more about gravitational wave detectors soon but anyway if a supernova explosion occurs in our galaxy then both gravitational wave detectors and neutrino detectors should observe the signal and by combining these two data we think we really understand the supernova mechanism of the supernova explosion and then soon after this supernova could also be observed by gamma rays that means by cta and therefore this way we expect that we understand the particular acceleration in supernova so in the multi messenger astronomy era neutrinos gravitational waves and gamma rays are going to be very important ok that's all from me