 Okay, I think we are live. So hello everyone and welcome back to the Latin American webinars on physics. My name is Joel Jones from the PUCP in Peru and I will be your host this day. So this is webinar number 91 and we are having a Tepei Catori as a speaker. So Catori San carried out his PhD at Indiana University in Bloomington, which was followed by a postdoc at MIT. He then became assistant professor at Queen Mary University of London, and is now associate professor at King's College London. So today Catori San will give us an update on the CP violation measurements at T2K and we're really happy to have him as a speaker today, given the fact that it's a very recent publication. So before we begin, let me remind all of the viewers that you can ask questions and comments on the YouTube live chat system, and these questions will be passed on to Catori San at the end of his talk. By the way, we have already one comment on our chat, which is, I'm sorry if I don't pronounce it correctly, it's Pruthi Mehta who's saying hello Tepei. All right, so we're all yours, Tepei, please proceed. Can you see me now? Yeah. Hi, my name is Tepei, I'm from King's College and today I want to talk about this T2K new result and I think most of my talk is focusing on how T2K works and then I go to a result. So let's share my screen. This one I think. Okay. So, so this is today's my talk, the constraint on the matter-to-matter symmetry violation phase in nutrient oscillation, and so the result was published on Nature last week, and the main result was, I come back later, so maybe I should say now. So I want to describe mostly to how the oscillation experiment works. So then, so the nutrient oscillation experiment using the beam, you need two things, the one is a beam and the other one is a detector. So I want to explain how these works in T2K, and a little bit about the nutrient interaction physics, and then finally moving to these oscillation results, and a little bit the future plan, which is SKGD and T2K upgrade and hypercamille. Okay, so let's start from what the oscillation experiment is. So, nutrient physics is a very big these days. And the center stage of particle physics, which is the two of the most prestigious one happening is this Nobel Prize, which was 2015. And 2016, there was a breakthrough prize, which is already for five experiment. K2K and T2K, and Cameland, Diabe, and again Snow and the Super K, which also won Nobel Prize. So nutrient physics is very popular. The reason, oops, is that nutrient physics offered you to measure something more. So now we know nutrient has a mass. So what we call standard model is actually this standard, neutrino standard model, which you mean the standard model plus three active massive neutrinos. And by introducing massive neutrinos, you have already new parameters. Okay, so this is different from looking for something new particle beyond the standard model, which you don't know you find or not, because these new parameters are something there, and you can measure it. And among them, maybe, so these are unknown parameters, so many of them already measured, but still there are several unknown parameters and maybe most interesting one is this Dirac CP phase, which is the topic of today's talk. The second one is the one we're mixing on the theta 23. This is the one, the first one measured with the high precision, but now you will have to measure with the higher precision. The reason is because people used to measure sine two theta 23, but in a high precision neutrino experiment, you want to know the value of a sine theta 23, then the degree of a 40 degree and 50 degree have to be differentiated. So it's coming back to the something we need to measure it. So in this moment, we don't know it's 40 or 50. And the other one is the mass ordering. So we know M3, sorry, M1 is lighter than M2, but we don't know where the M3 is. It could be the heaviest, which makes sense for many people, so it's called the normal ordering, but maybe M3 is lighter than them, which is called inverted ordering, and we don't know yet. There are three other unknowns, which is we don't know neutrino Dirac particle or Majorana particle, and if that is Majorana, there's a Majorana phases. And finally, we don't know the absolute neutrino mass. And those are something I don't talk today because they are not relevant for oscillation experiments. So you need a different experiment to measure it. And if you focus on the oscillation experiments, so many of them are designed around 1 to 10 GB, which I want to also talk. Okay, so formulation. So the key is that I want to go very briefly. So neutrino flavor against it, which is the mixing of mass against it. And you can prime to write this mixing matrix with a three mixing angle and the one CP phase. And again, this Majorana phases are not in the oscillation formula. And you can write an oscillation formula in this way, which is a very generic way. By the way, I also talk a lot for this two flavor oscillation formula, which is simple, and it's not enough to describe Delta CP, but it has a lot of insight how to design oscillation experiment. So that's how the two neutrino oscillation formula looks like, including the mass and the angle. The formula we focus on is this is the first order over Delta CP. So now this, the Yarskog invariant is in the oscillation formula. And especially this is a formula for a new mute to new e oscillation. So minus signs for neutrino and the plus signs for anti neutrino. So if there is no CP variation, there is a JCP zero, you see the same for this oscillation. And the difference comes as a CP variation. And as a scale, it's not the small if you see this way. So it's a plus minus 25% changes of the oscillation probability. When you fix your baseline to be 295 kilometers, which is T2K experiment mystery. So it's a 25% effect and you might think it's big. But if you see the scale. So we are talking 5% oscillation become 6% or something like that's an order. So it's kind of small. So expected oscillation probability is in general small. So that's a better statement. So in the neutrino mode, you expect enhancement of cross section when this delta is minus pi over two. And the anti neutrino, you expect the separation with the delta is minus pi over two. And if the delta is pi over two, you see the separation of neutrino oscillation and you see enhancement of anti neutrino oscillation. So that's the kind of effect you want to see it. So these are overview of like all oscillation experiment. And the present experiment include the T2K, NOVA, microboon, deep core, things like that. And the future one include the HyperK, Dune, Ping, Orca. And there are a few class of experiment I don't talk, which is a coherent or reactor or so on. And what is striking here is that all experiment is around one to 10 GB. And the reason, you can imagine this way. So if you want to see neutrino oscillation, you want to make this phase part of your oscillation to be around one or pi over two. And the delta M square is like a 10 to minus 3 EV square. So which makes L over E to be around 500 km per GB. So we don't have a many choice for this value because if the error is really big, if the error is big, then experiment, your detector is far away and your flux go down. So you don't want to that, then you need a more neutrino. So you want to make L to be not too far away, but if the error is small, then your E have to be small. But if the E goes smaller, then the cross section goes smaller. So your interaction rate to go down. So you have to adjust these two parameters around the E. And you find the only few nice combination. So T2K, the error is 300 km, and E is 0.6 GB. And NOVA, error is 800 km, is 2 GB. So in this way, every oscillation experiment end up around one to 10 GB. But one to 10 GB is also the region, your cross section has a big systematics. That comes later. Okay, so how do you measure oscillation? For the data, you create a neutrino beam and you measure it. But you measure twice. The first is you measure by near detector. So that's how you find the neutrino flux before the oscillation. So that this measurement is focusing on muon neutrino to electron neutrino. So I pretty much only talk about that one. So you measure muon neutrino at the near detector. And the far detector, the electron neutrino, which is a signal of muon neutrino oscillation. But also you measure muon neutrino to constrain all the systematics. So that's what you measure for data. And the simulation, you want to simulate the situation. The first is you want to simulate neutrino flux. And then both near and far detector. And then you simulate neutrino interaction, both near and far detector. And then you want to simulate detector response. And finally you apply oscillation formula to see how this detector response change at the far detector. So you have this description of the experiment by simulation. So the oscillation analysis is to compare this data and simulation. And you'll find the right parameter from this simulation is. In the meantime, near detector information used to constrain system. So that's the overview of this data simulation and oscillation analysis. So from here I want to explain these elements one by one. So that's the overview of T2K. So T2K is a Tokai-to-Kamioka experiment. It creates neutrino beam at the J-park. And these neutrino propagate roughly 300 kilometers underground because you have to take account coverage of the earth. So you shoot neutrino to the downward. And this is measured by super-Kamioka detector, which is a far detector. All right, so let's start from neutrino beam. So this is a J-park, which is very close from the beach. It's okay beach, not the best beach you can imagine. So the first you have to accelerate protons. So let's start from Rynek, which is a 400 MeB linear machine. And these protons send to RCP, rapid cycling synchrotron, up to 3 GB. And then this is sent to a main ring, which is 30 GB. And these protons are finally extracted for the beam line and the collides to the target to generate neutrino beam all way to Kamioka. And the primary beam line is all protons. Okay, so the neutrino beam line starts from protons. So there are 30 GB protons and the main ring. And this is the structure is, so these protons make the pulse. Each pulse is a roughly five microsecond width, and each pulse are separated 2.45 seconds. So every 2.45 seconds, there's a one shot of five microsecond pulse. But this five microsecond pulse also has a microstructure, which is eight bunches. That's what you see from here. And you can see it these from the neutrinos. So these are structure of the protons. But that's how you generate neutrinos. So neutrino maintain the same timing structure. So it's a left plot. This is the near detector information. So this is the measurement of near detector about neutrinos. And you see it's eight peaks. It's these eight bunches on each pulse. And after 300 km propagation, you see the same timing structure as super Kamiokande, which also shows eight bunches. So these pulses are the standard technique for this kind of experiment to suppress the background, because you know the beam is only five microsecond. So the chance cosmic ray comes in pretty cool. So that's how the picture is. So the proton is accelerated in the main ring. And once you reach to the enough energy, it's extracted to this beam line and send it to and bend and collide to the target and generate neutrinos and send it to Kamioka. So once the proton is extracted, now it's a secondary beam line, which is a generation of neutrinos. So the way you generate neutrinos is following. So the first protons collide to the graphite target, and this target is located inside of the horn one. So something like that. And this collision makes a shower of mesons. And these mesons decay to neutrinos. Okay. However, this horn has a current and will generate a magnetic, the troidal field. So neutrino mode. They are generating the field so that you focus the positive mesons and the de-focus negative mesons. The purpose is, in this way, you can increase the flux roughly 17 times. And also you reduce the background coming from the negative negative meson decay. And for anti-neutrino mode beam, you switch the direction of current, and then you focus negative mesons and de-focus positive mesons. So magnetic horn is a vital for a neutrino experiment, because by this device, you know, the experiment takes 17 years will become one year, right? Because you increase flux 17 times. But also it's such an extreme device. And you see from this picture, a cartoon. So this device are located in the room of helium, one meter of concrete block, and then two meter of iron blocks, because it's highly radioactive. And the operation of this device also takes extreme 250 kilo amp current, which also generate huge noise. I just, I want to show it. So this is the testing of one of the horn in the laboratory. And I want to show how the sound is. So this is the sound of neutrino. Basically, let's see. So you see the heat every 2.5 seconds. So that's the moment when the current pass through and generate this 1.7 Tesla field to focus the mesons. So that's happened every 2.5 seconds in our experiment. So that's how you make neutrinos. There are a few more tricks. The one is this off axis beam. So this neutrino beam designed to, so the experiment designed slightly off from the direction of the protons. And the reason is because in this way, you can narrow your spectrum. So this black histogram is the on axis spectrum of neutrinos. But if you go a little bit far away from the axis, the spectrum become narrower. And in this way you can maximize the peak at the location of oscillation maximum. So that's some experiment become more sensitive for oscillation. So that's the first thing we do. And how do you predict this neutrino flux is pretty important, even though we measure that near detector. And prediction is, I shouldn't say impossible, but it's very difficult because it's a, it's a, it's a hard on physics type of hard on physics. And the way we do is that we use data from the, the hard on measurement. So we trust what we measured more than the simulation. So this is an experiment at CERN dedicated for T2K, which is called NA61 shine. So in this experiment, they have a target, we use that T2K, and they actually measure the distribution of mesons. And we use this information for our simulation to improve our flux prediction calculation. So that's a summary of our neutrino beam. So in this data for today's result, we have this 1.5 times 10 to 21 POT POT standard for protons on target for neutrino mode, and the similar number of anti neutrino mode data. So this figure shows how we accumulate the POT is. And this histogram in the bottom described the neutrino flux prediction. So for the neutrino mode, the, the flux is dominated by new neutrino, which is a 97% dominant at flux peak and anti neutrino mode. On the other hand, which is dominated by a new one anti neutrino beam, which is 96%. There are small contamination for the opposite sign of neutrino opposite for anti neutrino for neutrino mode and neutrino in anti neutrino mode. And also there is an extra neutrino this is important because extra neutrino is background. So we want to understand this distribution carefully. And error is roughly 9% and this error is dominated by the prediction of hard runs. So all error is associated with how we transport this hard run measurement at the shine experiment to T2K. And in the future, we are expecting the reduction of this error down to 5%. So that's an ongoing issue. Okay, now the detector. Before moving to the fire detector. So need to know the measure by near detector. The wine is the ingrid, which is on axis. And otherwise, and it waited, which is off axis. So in grade is mainly for monitoring of the neutrino flux and the energy to 80, which is the off axis, which mean it's on the same line of fire detector. So we use this energy to 80 data to constrain is a variety of different systematics. Okay, let me talk ingrid for us. So in grade, which is the array of the 16 modules and all of them are roughly one meter cube detector, and it's a simulator of the it's a sandwich since later with since later and iron track. In grade, we can monitor the flux. Distribution and nominal accuracy around the point one million. So you see this figure this one shows distribution of a flux with different location of ingrid for both horizontal and vertical direction. So this 16 modules are distributed in several meters away. And this data shows how the ingrid. The track looks like maybe this is the new one from me on. By the way, in this talk I mentioned since later many times. But when I say since later it usually mean organic plastic since later with fiber reading and Silicon PM sipping reading. So that's kind of standard for this community. Okay, so this on axis site. Now we have a lot of other detectors, because there are lots of space. So why the proto module, which is a free active module and like ingrid and wagashi is a water target 3d simulation array. This is a baby mind magnetized tracker made by son. We also have an emergent detectives called the ninja. So these are all all variety of R&D and future detectors. This detector may be more important, which is the energy to 80. So energy to 80 is a combination of many detectors. And the purpose is, you want to measure like all detail and the different topology of neutral interactions, and use this information to constrain the both flux and the cross section systematics for this oscillation analysis. I want to give you some example. So this is an example of scored FGD one CC one by sample. So this mean neutrino is interacting with FGD, which is a situation since later tracker and produced charged left on and the pile. So you see this trajectory. So this is a candidate event display. So the heat happen at the FGD. And this trajectory is tracked by the TPC two of gas TPCs, and all of them are in the magnet. So you can measure the momentum. And the left histogram describe the data and with the simulation and the simulation has a different channel. So you see the contribution of different channels for this particular topology. So this is a one of 14. And so we have another 13 samples that look similar but different policy. So the right histogram. This is a CC zero pi. So in this case, the outgoing track is just for charge left on so no pile. And you see the differences. So the left plot. When the case you generate a pile. Of course, the dominant contribution is the baryonic resonance pile production, which is a green contribution. And the right plot. If you don't see the pile, the dominant contribution is the CC QE, which is a signal channel. So the trick we use is we perform this kind of many different measurement simultaneously so that we understand the contribution of each channel. And also the era associated for each interaction mode. Okay, so that's the entity and now moving on the fire detector. The fire detector is a I say the maybe famous super kind of detector, which is a 50 kiloton water channel detector. It's famous because no Nobel Prize 2015. And maybe people familiar with this how it looks like inside. So this one is a picture of the inner detector where the 11,000 over 20 inch PMT is surrounded. 20 inch PMT is mean 50 centimeter roughly so you see how big is if you complete with myself. Oh, and also, in case you never heard of PMT so PMT stand for photo managed prior to so it's a standard device to detect photons. So using a photoelectric effect, you can convert the photon to electric current. So that inner detector is something you see it in the picture, but this inner detector is inside of the bigger time. And there is a region it's called the outer detector is, and that region also has a 2008 inch PMT and to reject the background. So you see these eight inch PMT attached with wavelength shifting plates. So the region, unlike the inside, you want to maximize the reflection so that you can detect any kind of background. So everything is covered with a white type of. So that's how super coming up and it looks like. So the measurement is the time and the charge information from all PMTs. And by using them, you can perform a particular identification PID, and also you can reconstruct kinematics. So, you see this pattern. So electron neutrino, what if the electron neutrino interact, which makes fuzzy ring fuzzy triangle ring. That's how the electron neutrino like. And when the muon neutrino interact with the water molecule, it makes a sharper chunk of ring. So the heat pattern makes the ring, but it looks cleaner. So in this way you can even tell what kind of particles are. And also, from the distribution of these hits, you can reconstruct the energy of the particle and the scattering angle. Once you know the energy and the scattering angle, you can reconstruct neutrino energy is so that this formula is because neutrino solution eventually you use neutrino energy. So you need to reconstruct neutrino energy is so it's a it's a multiple steps. So you can reconstruct the hits of the photon and you reconstruct energy and the scattering angle of charged left and then finally you can reconstruct neutrino energy. And the right is that is the data distribution with the function of a PID. So in this experiment, which is a signal of a muon neutrino oscillation, there are two major backgrounds. The one is this intrinsic background, because even you measure the electron neutrino, some of them are contamination from the beam. And that's roughly. It's only 0.5% of the whole beam flux, but in the event, which is roughly 10%. The second one is a mis-ID background, because this kind of water chain called detector, you can't distinguish electron with the photons. So once you generate gamma ray, it's mis-ID as electrons, so which mean this mis-ID as an oscillation signal. And the majority of these then are coming from some kind of a neutral current interaction. So that's what you see this yellow histogram. And the second one is this neutral current pi-zero production. So if you generate a pi-zero by neutral current, and then if you if you miss to detect one of gamma ray, then you see the single gamma ray from neutrino interaction, so it's mis-identified as an oscillation signal. And that also contributes to another 10% of the old new E. Okay, so that's how detector works. Let me talk a little bit more the details about interactions. So, as I mentioned, neutrino interacts and generate charged leptons, and that's how you find the neutrino energy. And the main channel for this process is called the CCQE, the charge current quasi-elastic scattering. And it's pretty simple. For the case of neutrinos, neutrino interact with neutrons and generate charged leptons and protons. And once you know this interaction is CCQE, you can reconstruct neutrino energy. So there is some assumption. So, and this assumption I call a QE assumption. And the first is this target neutrino at rest. And the second assumption is, yes, this is the CCQE interaction. Because when you reconstruct neutrino energy, you are using the information, it's a two-body interaction. And if you see the data, so this is again the cross-section data from the world and where the T2K experiment is, you see that the data has a quite a big error bar. So it's a simplest interaction but still not the greatest measurement in the world. The reason is because of all kind of a nuclear effect. And so that was the first pointed out by this Martini et al. And what this paper suggested was neutrino interact with the nuclear, that's the one case. But not so rare case is that neutrino interact with two nucleons together. So there's some kind of a correlation between nucleons also contribute for interaction. And one is more, this kind of a correlation change cross-section up to 30%. So that was shown by this plot. And the data from Miniboon and the Martini et al. explained this Miniboon data pretty well by this idea. So now this is another cartoon. So neutrino is sometimes interacting, not one nucleon, but the pair of nucleon protons. And in the Schrodinger detector, we don't measure these protons because they are below Schrodinger threshold. So you can't tell from the data. So this is an important background and new type of background. So now we have a huge community effort. So both nuclear cellists and experimentalists are trying to understand this kind of phenomena and predict correctly. Because the only way to reject this is we need a better model. So this whole business is called CCQ puzzle. And at the point of last year, there are lots of advanced nuclear models. And those more or less describe Miniboon data well. So we understand the role of these nuclear correlations, but the nuclear correlations, but still we can't really fix the parameters completely. So this gives error and we need to be aware of it. And for this analysis, we use this Berencia 2B2H model from the group at IFIC in Berencia. Another important channel is the pion production, which is a similar reason. So when the neutrino interacts with the nucleon and produce charged leptons, so that's I call signal. But sometimes neutrino interacts and produce charged leptons and pion. That's the background. That's fine because you can reject it. The problem happened if you can't measure this pion and not so small chance, this pion disappear inside of the nucleus. It's a nuclear effect called the pion absorption. And this kind of nuclear effect, it's called the finite state interaction, have to be modeled correctly. Because again, this is the background we have to simulate. So the case of neutrino disappearance, the dip of oscillation give you the amplitude of your oscillation or mixing angle. And the location of the dip is the phase of oscillation, which is a neutrino mass. So the location of this dip or excess is very important. But if you have a background, which is not the quasi-elastic, then these background migrate in this region of dip, so you have to predict. So that's a very important background to understand. The situation is not great. So this pion model, we have a brighter models and FSIs, but we don't have a complete understanding. Minerobae experiment at Fermilab, which is probably the most advanced experiment on this subject, measured four different channels, and they try to simultaneously fit all the parameters, but it didn't work quite well. So there is a still ongoing issue. And it's the right figure explain why this is so difficult. This is the comparison of one of the simulation called the Jibu with the pi-zero production data. But if you see the cross-section, the red is data. So the blue band is the simulation without any FSI. Well, first things happen is the pion absorption. So around the location of the data peak, the pion disappeared. Inside of the nucleus, pion rescheduled and energy go lower. So the peak of the cross-section shifts to the lower region. So that's the second thing that happened, pion scattering. But finally, some of the pi-zero are coming from pi-plus because of the charge exchange. So yeah, you need to predict both pi-zero and pi-plus and all of these process correctly. And then finally, your data and simulation agreed. So Minerva tried to do this by measuring all the channels. And yeah, it was very tricky. So that's the situation is. So this right figure shows the simulation of a new treatment interaction and predicted errors. And what you see is error is quite big. And the blue band is the location of the T-trick experiment in the region. So the error is quite big. So all you have to do is that you need our own data to constrain these. And this subject is quite popular. So now we have a chapter in the PDG. And there's a new collaboration called Newstack, which I'm also the member is. And we try to promote this theory experimental collaboration to understand nutrient cross-section. Okay, so moving on the results. So the first step is to tune our model. So our new treatment interaction model is tuned from the external data, like Miniboon, Minerva, Saiboon, K2K Minos and bubble chambers. And this right figure is what we get. But this is a too big error. So we have to use the internal data from ND280 to constrain all parameters. And so this is very important for us. And you see this figure on the right bottom, one of the example. So as I said, this FSI parameters like amount of time absorption or risk scattering inside of the nucleus. So these are all process have 30, 40% of errors. But by using these 14 different sample from ND280, these errors go to less than half. So 10 to 20%. And after by using all these samples. So the error suppress more than half. So for example, election like ring measurement. So without internal constrain, the error is 17%. But with this ND280 simultaneous fit, the error go to 9%. So this is vital for systematic separation. Okay. So now is measurement. So these are distribution of electron neutrino candidate. So which mean electron candidate. And the top figure is for neutrino mode. And the bottom figure is for anti neutrino mode. I see the typo. So this is the say, should say minus five or two. So what you can say from here is that for neutrino mode, you see the data is higher than the simulation. So you see some kind of enhancement. And anti neutrino mode, the statistics is a bit low, but now you see the separation needs. And this is what we expect when your CP violation phase is negative. So that in the table, you see that the total prediction is 73% using including a CP violation. And the data is 75. And for anti neutrino, the prediction is around the 17 and the data is 15. So that's why this is the last plot for this oscillation analysis. So oscillation analysis, we fit all oscillation parameters. And our interest is three parameters delta CP and sine square theta 23 and delta M square 32. So these has a flat prior. And the other oscillation parameters coming from our external constraint. So which mean these are PDG and Gaussian error. So the top figure shows X axis is the delta CP and Y axis is the sine square theta 13. It's a bigger contour is a case if we don't use data 13 information from the reactor neutrino. But once we use this external constraint, you have this smaller contour, this one. And it is a one sigma contour. The bottom figure shows X axis is a delta CP again and Y axis is a sine square theta 23. And you see this three sigma contour is a big one. So that this is the bottom line of this analysis is because we used to see three sigma spreading to the whole space. But now the three sigma contour also the clothes. So which mean now if you increase your statistics, you can make this contour smaller and smaller. And eventually you can find the right values. The one caveat is so it's a three sigma contour is closed. But this three sigma contour also include zero. So the zero is still the one of the option in the three sigma. So that is also shown this figure in this left side. So this is our best measurement and the DC the three sigma contour. Right. We also tested mass hierarchy. The way we do is that we just also the fit separately assuming a normal ordering and inverted ordering. And we have a small the weak preference of the normal ordering with the 89% of posterior probability. So that's our selection result and my last few minutes, I want to talk about the future. The first thing is SKGD. So super cameo candy is a plan to be doped with 0.1% of a gadolinium. And the main purpose is so this gadolinium has a high cross section and large Q value. So it's a very sensitive for neutral capture. So basically super cameo candy become visible for neutrons. And in this way, you can imagine neutral current at the low energy, especially for DSMB. And our target is this 10 to 20 MB region. And we have enough sensitivity. So we expect few events per year by this 0.1% of gadolinium, which is ongoing. But this gadolinium is also useful for oscillation analysis, because there are more neutrons for anti neutrino. No, sorry. So more neutrons from the neutrino interactions. So one of the big background for anti neutrino event are neutrinos. So let me go back here. So the bottom figure is the anti neutrino mode data. And the red is this oscillation signal from anti muon neutrinos, but it's also contained lots of interactions coming from neutrinos. So this is a background and you want to suppress. And the neutrino interaction makes more neutrons in a final state. So you can't distinguish electron and the positrons from the data, but by measuring the amount of neutrons, you can find its charge is a neutral neutrino and neutrino. And this shows the case, you know, by assuming the zero neutral or more than one neutral and you see how the background suppress. So, so this SKGD is not only astrophysics, but also it's a great for oscillation experiment. But now super cameo candy is not pure water and gadolinium. So you want to make sure there's no leak, because we have a big leak. So last year on two years ago, we have a big campaign to fix the wall of super cameo candy and sometime replace all the dead PMT. And now we confirm there's no leakage anymore. So we are ready to dope gadolinium. So that was a fun time for all of us to work in the inside of super cameo candy. In the meantime, there's a T2G upgrade is planned. There are two parts, the one is that this JPEG neutrino beam upgrade. The main part is this repetition. So this moment that each pulse comes every 2.48 seconds, but we want to make it twice faster. And the key is that we need a better power supply. So this test is ongoing. And we are hoping to reach to this 1.3 megawatt power at 2028. There are other things is the upgrade of the near detector. So this port detector, which I didn't discuss today is replaced replaced with a new detectors. The wine so called a super FGD. It's a three dimension and situation tracker. And it has a very high resolution you see from this picture. I mean, of course, it's a simulation. So there is a new TPC, the gas TPC, and you allow to measure like a high, high scattering angle event. So we're expecting this to come soon and then it's a better near detector data. But our great goal is this one hyper cameo candy. So hyper cameo candy is a bigger water tank. So the first generation was a cameo candy. It's a three kiloton and the second generation is a super cameo candy is a 50 kiloton. And the third generation hyper cameo candy is a 260 kiloton. So the construction started from this year. So that's great. And physics is also great. It's an MEB to TV physics, covering all kinds of new tree nodes and all kinds of new physics. So no better price go to come your candy on 2002 and 2015 for super case. So now you can do some kind of linear extrapolation when you get the Nobel Prize for hyper. So hyper has a oscillation program to cover all of them. The first is that we have a chance to reach the five Sigma Delta CP measurement. And in this stage, we are limited with the system at six error. So that's another reason we want to focus on this cross section, she's a matrix because that's a dominant. So the, the, we need a bigger detector and one statistics, but also we need to reduce systematic errors. The mass ordering is not easy by beam because the matter effect is weak, but we expect from atmospheric neutrino to find a mass ordering. So basically hyper K can find all of oscillation parameters. The other physics are also great. The solar neutrino's. So that we have a new high quantum efficiency PMT is but the dark rate is a bit higher. So the work is ongoing to reduce that great. And also there is a new type of the module it's called MPMT and it's the prototype is so this is the motivated by chemistry net is ongoing to be developed. The proton decay work is great. Both the pion channel if I channel and the new K channel hyper K would be the better than anybody else. And also there are many other channels major. And finally for supernova neutrinos. So the now the hyper cake reach to the mega plastic. So we can cover the supernova explosion at Andromeda, but we also try to extend all the way to M81, then you can see the supernova neutrino almost every year. So the future of T2K and SKGD and T2K upgrade and hyper chemical I think all of them looks very bright and great. So let's make to my conclusion. So T2K is a second generation long base and neutrino duration experiment in Japan. So neutrino is from J Park and measured by super cake. So in this analysis, the data from 2009 to 2011 was used and oscillation showed asymmetric behavior. So you see the enhancement for neutrino mode and the separation for anti neutrino mode. And this can be interpreted as a negative CP violation phase. And as data shows, this is the preferred region and you see the close three sigma contour. And we have a lot of future plans, including SKGD and T2K upgrade and hyper chemical and all of them are ongoing project. So thank you for your attention. Okay, so let's see if my video can start. Okay, thank you. Thank you so much for the talk. Let's see, I'm going to exit full screen and okay, great. So it was a very interesting talk. Thank you so much for a for giving us such a good talk in such a short amount of time. So now, okay, so before we go to the to the audience in YouTube, since they they probably have a little bit of a lag, let's let's go for questions with the audience with anybody here in the audience on the webinar audience would like to make any questions. I have a couple. Let's see if the others have any really not even Roberto, I don't believe. I heard a couple of questions myself. So so okay so so since we're already on. You showed your result. Lately, could you could you go back to your previous slide where you see where you show your main result. So there the the the interval for inverted ordering is is much smaller and that one does reject a city conservation, but I assume that is because a the minimum chi squared a for inverted ordering is larger so so then it opens up a doesn't have such much space to open up before you do that the cut on the three signals. Yeah. I think my understanding is much simple, because the data, what happened for our main result. We see too many nutrients. So, our enhancement is maximum possible. And this maximum possible to mean you have a three combination. The CP is minus pi over two, and the normal hierarchy and upper octane. You know so you are using all three parameters to maximize oscillation needs. So some sense, some sense, we are too lucky, or we should be careful. Because our result is longer than sense. So, so that in practice or same reason yeah we prefer normal because we see too many neutrinos. I see. I see. Okay, so. Okay, I don't know if there's any other questions I have a couple more, but let's let's start with the with the with the chat. Okay, so there's a lot of people saying hello hello hello so apparently you have a lot of funds. So the first question comes from Victor Valera, who asks, what is the one one day new mode. Yes, so that's it's something I didn't discuss. It's a bit controversial. Let's see. So, so the measurement the oscillation signal are electron neutrino. So electron neutrino CC candidate are the. So if you measure electrons that interpreted electron neutrino for neutrino mode, and the same as for anti neutrino. However, sometimes you we cannot also measure the pion. And we also use this as a signal. And these are pion the way we measure pion in a super cameo candy, you can't measure the track, but pion pi plus decay and generate another electrons, decay electrons so D stand for decay electrons. So one zero DE mean, you only see one single isolated electrons, which mean electron neutrino candidate and anti neutrino mode is same things. And the one E1 DE mean you measure electrons and high energy electron track, but after you see low energy electrons coming from me on decay. And this one indicates there's a production of the pions. So we also use this channel in this oscillation, but this contribution is pretty weak. So I would say this sample didn't contribute. And you see the result is so we expect around a five event for this one E1 DE and what we measure is 15. So we measured too much of this and I would say this is a statistical error, but we'll see for more data. Super. So let's see if. Let's see. Alfredo Miranda is asking me to meet my mic we already did. So, let's see Pablo, Miguel C. Fuentes. So, Pablo Miguel C. Fuentes is asking. What is the results. So, so there's a question of basically a why. Can you translate the question a little bit. So, so why the question is why can't you distinguish Majorana neutrinos in these experiments. What's what is the difference for my run and the dirac, I think that they always measure the charge left on and they there's no signature. And there's no difference in the oscillation formula. So that's the main reason. Well, in this moment, the neutrino less double beta decays are only possible experiment to see the difference. There are a few people suggesting some scattering experiments, because they have a different current. So theoretically, if you have a highest precision that you can measure difference. But in a realistically, it's impossible. Let's see. We have we have a lot of questions on that on the chat. Before before we do that, let me do, let me ask one more one question. So you mentioned the background from neutral, neutral current interactions right which come from a production of a pion which will decay into into photons. Right. However, in, in, right that that that's perfect. So however, when when you have a charge left on, right, you you're generating a ring, not a couple of photons. Right. So, so, so my question is how come do the the pions are such a background for you if they're just emitting two photons. So, if you measure two photons, fine, then you can reject. But the, the chance pie zero makes only one photon is not small. And so the main reason is just the kinematics. So if the pie zero decay, and pie zero is boosted to the direction of one of the photon, then the energy of one photon go zero, and all energy go to other photon. So the pie zero naturally decay to single photon. So we always have this background. And the only way is yeah we need to predict. Sometimes decay, the one photon is, you know, it's not easy to detect or you know, there are, there are several reasons but major reason is this asymmetric decay. And we try to reject as much as possible, but there's some contamination. Sorry. So this is a minor process, which is sometimes delta directly decay to a photon. And this process has a very small cross section, like a 10 to minus 41 centimeter square at 600 MB. Previously nobody cared, but now we came to the enough sensitivity. So this situation, the radiative decay of Delta is also the background. And it's like a 20% 30% of this pie zero case. Sure, but my understanding was that the charge lepton coming out from the, from the nutrient interaction would not generate one photo and it would generate like a series of photons that will be distributed like a ring. Okay, so, so that's a different photon. So I say photon background mean a gamma ray, and these gamma ray makes a electromagnetic style of the chain of ring. So the one gamma ray makes the ring of photons, which looks like this case of new ECC. So that's that's why it's background and the charge left on. Yes, it's generated a photon the chain of ring, but that's makes a sharp ring. So, so that's why you can distinguish it. I see so so that photon from the from the pion will eventually rescatter and produce the ring. Yeah, that looks like an extra nutrients. I see, I see. Thank you. Thank you. Okay, so let's go back to the to the chat. So, Victor Valera comes back and he's asking to explain antimatter symmetry through leptogenesis. How large is the CP phase expected to be. This is because a small CP phase in this quark sector is too small to explain it. I can't let any theorists in here to answer for that question. So I, my quick answer is I don't know. And actually even I'm not sure this statement that clear quark sector is too small and left time is big but I think I agree we don't know how small it's small and how big is big. Well, I think that you can, you can quantify that that the CP relation in the quark sector is too small maybe somebody else in the audience has a better idea. But my understanding is that you cannot link the CP violation on the neutrino sector with directly with that in leptogenesis processes, but maybe somebody else in the audience can can can give us So, so that was, by the way, I want to say one more word. So that was one of our main question for this result. And so we, we, we are very careful to state in the paper. So we, sorry. So we said, we don't say the delta CP of a lepton sector is the solution of leptogenesis and value asymmetry. It's this connection have to be clarified by theory or model, I think. I agree. Okay, so let's see. Let's see so Pierre Lasorak is saying hi to pay. Can you explain the sensitivity to is in plot on your last slide. I don't know what the SM maybe supernova what's the SM. Maybe this one. So what is the question about. So the question is, let me, can you explain the sensitivity to plot on your last slide. Yeah, so, yeah, I didn't explain anything. So this is the probability to see how many neutrinos from the deep supernova happening at certain distance. The black line is more than one nutrient detection. And the blue is more than three neutrino detection and the green is the two, and each line is a different oscillation scenario. So, if you require only one neutrino observation, then you know, even three megaparsec or four megaparsec location you have like a 20% chance to see it. That's not very interesting because that's so much background and you have to cross the finger a lot. So, if you want to see, you know, several neutrinos, let's say three neutrinos, then you want to have supernova pretty much at Andromeda. So we have a still, we have a megaparsec view, but really interesting is to reach around the four megaparsec, then you cover so much galaxies, but up to this M81, we don't have many target. So, so anyway, that's how you read this plot. Super, super. Thank you so much. Let's see we have we have a lot of questions. So the next question comes from Peranava Teja. What is the energy threshold of super K and what is the expected thresholds for hyper K. The question is primarily in the context of looking for supernova neutrinos. Okay, so supernova neutrino, we always assume 10, 10 MB. The detail is a bit complicated because solar neutrino, we assume lower, we assume like a 45 MB. So that's the energy threshold is. And also, we, it's a challenging. So a lot of hyper K development is focusing on oscillation. And we are a little bit. We're not really sacrificing a lot of the physics, I have to say. So that's why this dark rate, for example, so we have a new PMT, which has a twice more quantum efficiency, but the dark rate is higher. So which mean you have a better measurement for oscillation or GB neutrinos. But if you want to do solar neutrinos, it's a challenging. So we are working on to make this dark rate lower. And also for the castle coverage is now it's not enough. It's a new device. So that's how we try to reach to this target for me be threshold for solar neutrino, then we can see this uptown, you know, of the MSW and supernova. Yeah, we always assume 10 MB and I don't know much detail of this. Let's go on to more questions. So, let's see. William Thompson is thanking you for the talk. And he's asking, how is a PID discriminator in super K defined. Okay, so that's the completely. So this is very complicated part, but the quick explanation is, so this likelihood is used all the information of timing and the charge of all the PMT. And the profile of all the detector is compared with the two assumption one is a electron like and other is a muon like, and then that's so likely for the best discrimination discriminator. It's very similar with other tranquil detector is using especially minimum. Actually, it's a I don't know. So yeah, that's the likely for the best time and the charge likely for you. Okay, great. We have another one from Edgar Chavarria, who's asking, why is a turn of scattered ring is wasted sharper for new e, and what would happen if you would have a new town. Okay, so I might have this fear on the background. So that the reason is because of the electromagnetic shower. So the case of a muon neutrino. So you make a sharp ring, but the electron neutrino produce electron. So first process is the electron has a multiple scattering. So the trajectory is not a straight. And one thing is there's an extra magnetic shower production. So the ring edge has a more blur comparing with muon and the towel. So towel is a problem for this community. So that because we are not very high enough. So that's the problem for everyone. So towel decay to a multiple hadrons and the main channel is to like a three pion or four pion. And it's very unclear signal. So we use a neural network to find and yeah we do claim the three Sigma excess of towel event, but from the event display it's impossible to tell it's how it's just a neutral current or not. Fantastic. Let's see. Let's continue. So Mario, Andres Acero tega asks, what would the exclusion confidence level be for Delta CP equal by I'm not sure if I understand the question. So there's a CP call by am I right. It was also mean Delta CP called zero. Yeah, he's asking for by. Okay, so, so there are way to the community has a two way to describe a Delta CP and super key to key terminology. We always consider from zero and so the both the left side minus and the right side positive. So the pie is here. And yeah so that was not excluded. So zero is here and the pie is there. Yeah, it's both neither excluded. It is excluded one Sigma by the three Sigma it's not excluded. And it's a number. I don't remember. So the zero is excluded with the two Sigma. I don't remember how much for the this side is excluded. So since since we are talking about that. I mean you you showed on your initial slides that basically having a zero or, or, or pie would shift the location of the of the peak. So, so I guess that with more data, you would be able to distinguish that better by by doing say a finer beaming. Would that be possible. I don't think the beaming really affect I think it's really just statistics. Now we have this at least we have a closed contour so expectation is a higher statistics will find the value and yeah three Sigma rejection of there. So I think I'm expecting three Sigma rejection of zero and the pie is maybe similar, which mean it will happen. So the T2K upgrade and if you improve the static systematics, you can reject zero with three Sigma so I'm expecting maybe that's the same time with pie is excluded because our best fit is around minus but of course if you have a more data this best fit point shift. So the rejection sensitivity of zero and the pie are not equal. Okay. Okay, thank you very much. Let's see if there are any other, I think that there are no more questions we did it. Everybody's thanking you, thanking you interesting question. Thank you very much. Is there a question from the audience. Yes, I have a question. Very nice your talk. I like it a lot. But I wanted to ask you, what is the capability of hyper coming candid for the to detect or to get some constraints or something related with the neutrinos coming from dark matter and elation. Um, so yeah we have some sensitivity plots I didn't include this time. It's good. So the energy. We can reach to all the way to TV. So we have a very unique sensitivity for this, the point source. I think that's already super K demonstrate, but hyper K will be better. I don't remember any numbers for this though. So but in principle there are there is would be an improvement with respect to it. Oh yeah it's a bigger and yeah the higher statistics and extended energy, you know, for the high energy. Great. Great. And another very short question, but because we can hear you in the slide that you're presenting now there is the supernova neutrinos and mega parts of distance. So that means with this plot that if there is any galak galak locally located supernova that was like the 1987 supernova neutrino. There's a lot of signal. Oh yeah, I mean that the, the number of neutrinos you would detect but a very nearby source is going to be enormous. No, yeah so the gas galactic supernova, if that happened that'd be great. There's a thousand of events and the timing information is also great. So you're going to study or, you know, how do you call that sexy or the oscillation. Not not neutrino oscillation but also this acoustic oscillation of the material or you know, so there are all kind of studies going on but it just, you know, we have to be lucky for this. Thank you. So that's why this extension of the view is very interesting. So four megaparsec is a kind of benchmark, then you see supernova neutrino every day. Every year. So you don't have to cross your finger anymore. Okay, I don't think we have any other questions. Let me check. Yes. I do have more questions. So, let's see Alexander Arguello Kiroa. In order to get the number of events distribution, how many the years, the duty you use in the simulations. And what about the value of the efficiency of the detective. The Monte Carlo we use, I only know this near detector is roughly 10 times. So we use a 10 times more Monte Carlo statistics than data in terms of year. And the efficiency of a super key. I shouldn't I should know this number I don't remember now. No, it's like a typical efficiency like they said, 20% to 50%. It's not like 5%. Great. Thank you. I have, I have one last question. So since you are in your results, including information from reactor, the data. Any plans to also use information from Nova, who are doing, I mean, they're doing similar things. So that's a very good point. And we do have a team working on joint the fit. So eventually, Nova and the T2K will do a joint fit and working together to provide oscillation result. We don't know when we can reach this point, but that would be a really great because we have a different beam and so Nova has a more sensitivity for matter effect. So you have a great result for mass, you know, the mass hierarchy and CP delta CP simultaneously. So yes, we are working on this, but it takes a while. Okay, thanks. Good, good to know. So I think that's it. The chat is finally silent. We've already done this for one hour and 15 minutes. Oh, no, we have another question. What's this? Oh, no, it's Alejandro who is repeating the last one from the chat. Okay, so enough of the of the physics webinar we like to thank you quite a lot from for forgiving the talk it's been great and your answers have been fantastic. So anyway, I'd like to, before finishing this, I'd like to remind the audience that we will have another talk soon, not on neutrinos but on axioms, I think, by Luca Visimelli. Very soon you can check all the dates of all of our webinars on our webpage, right? So look for us in Google, if you don't know it, no physics webinars. So that's it. Thank you very much once again, and see you all very soon.