STFC-RAL-CR03 R61: Introduce your experience from Vietnam.
STFC-RAL-CR03 R61: Okay, thank you very much for coming. Yes, Thomas and I will want to report on this conference on material physics.
STFC-RAL-CR03 R61: See, this is a beautiful place where it was hosted. So, this is a series of conferences. It's the same series as the encounter going on in the Lois.
STFC-RAL-CR03 R61: They're not just from theophysics, but high-energy physics in general. They're organized by time.
STFC-RAL-CR03 R61: is the MMU's Physicist, mid-sized workshop with, like, 50 bucks.
STFC-RAL-CR03 R61: So, as usual, the first thought was very interesting, and I want to show you that. It was historical archived materials on the Tree of Leeds from the Kamiaca
STFC-RAL-CR03 R61: laboratory, which is placed in Japan.
STFC-RAL-CR03 R61: So, as you know, in 1987, we have this… we have this famous supernova explosion. This is the same portion of the sky the day before and the day after.
STFC-RAL-CR03 R61: Like, this little star, Spoil the government.
STFC-RAL-CR03 R61: So, the experiment that maybe we saw this neutrino is Kanukanda, which was hosted at Canioca, and they showed this plot, which is actually the original plot, which showed… which saw this promote, right? So, what you see here is the tide.
STFC-RAL-CR03 R61: Riding to the left, because it's Japan.
STFC-RAL-CR03 R61: And, you have this background lighter, and then this Sunday first. You have to turn on.
STFC-RAL-CR03 R61: That's what it looked like. And notice that 3 minutes before the supernova, there is a gap, because the desktop that's ever been taken, so had the supernova come 3 minutes earlier, we would have missed it.
STFC-RAL-CR03 R61: Then they've shown this one. This was the first observation of solar neutrinos, these plots. So what you see here, basically, the vertical axis is number of events.
STFC-RAL-CR03 R61: And horizontal axis is the kind of the angle between the direction the neutrinos coming and the direction from the sun.
STFC-RAL-CR03 R61: So you have a peak at 1, but the angle is 0, and that shows that these neutrinos come from the Sun. It was the first discovery that neutrinos come from the Sun.
STFC-RAL-CR03 R61: Correlational indirection.
STFC-RAL-CR03 R61: This was the first observation of the atmospheric neutrino anomaly.
STFC-RAL-CR03 R61: So from the atmosphere, you get some extra neutrinos, and you get some new neutrinos, and these are the energy spectra measure coming in the APA.
STFC-RAL-CR03 R61: As you see, the electrone neutrinos match the multicarlo, but the middle neutrino show a large deficit.
STFC-RAL-CR03 R61: That was the first hint that we have latrine oscillations. What's happening is that this new mule
STFC-RAL-CR03 R61: Are not measured because they transform into being towel.
STFC-RAL-CR03 R61: Can't see those.
STFC-RAL-CR03 R61: And then the last thing they showed for history was, in 2001, there was this famous accident in the Supertour Canada at the back tournament.
STFC-RAL-CR03 R61: which is this big tank with PMTs in the water, and one of the PMTs exploded.
STFC-RAL-CR03 R61: And it created a shockwave in the water, which made the next GMC explode.
STFC-RAL-CR03 R61: Which created a shock wave, which made the next BMG explode, so it was a chain reaction.
STFC-RAL-CR03 R61: And half of all the PMTs exploded. It was a disastrous event. So what you see in this picture is all the PMTs down to this level are fine, and all the ones on this level down
STFC-RAL-CR03 R61: You know, 7,000 employees were export.
STFC-RAL-CR03 R61: It wasn't… It was a tragedy.
STFC-RAL-CR03 R61: And then they've shown this email, it was sent from the next day, sealed by the director of the laboratory.
STFC-RAL-CR03 R61: When we said, we will reveal the detector, there is no question.
STFC-RAL-CR03 R61: Always did.
STFC-RAL-CR03 R61: Yeah, it should, and indeed, influence.
STFC-RAL-CR03 R61: Two years later, it was fully functional.
STFC-RAL-CR03 R61: Anyway, that was just a type material, which was interesting to show. Let's briefly just give a framework of the theory of the neutrinos. So, there are three types of neutrinos in the second model, the muy, the new, and the tau, the flavor base.
STFC-RAL-CR03 R61: And they have two masses, mi1, mi2, and mi3, but the best, the mass base and the player base are different.
STFC-RAL-CR03 R61: So these ones have defined mass, and 1 and 2 and 3, and those ones have defined flavor.
STFC-RAL-CR03 R61: But when a train interacts, it shows up with a flavor, but when it freely propagates, it does it according to the mess.
STFC-RAL-CR03 R61: And so there is a unitary matrix that connects the two bases.
STFC-RAL-CR03 R61: And it can look like that.
STFC-RAL-CR03 R61: And so, in general, there are three flavors, so you need to mix all three, but turns out, there's a very useful thing, and this is really the only formula we need to know to understand the field of physics, mostly.
STFC-RAL-CR03 R61: In most cases, only two neutrinos are relevant, and where only two neutrinos are relevant, simplifies a lot. So this formula tells you the probability that you have… you start with a neutrino with flavor alpha.
STFC-RAL-CR03 R61: And it transforms into different flavored beta.
STFC-RAL-CR03 R61: After running some distance out.
STFC-RAL-CR03 R61: Okay? And the probability looks like that, so there is… this term here is just a constant of nature, and it gives you the amplitude of the escalation, so this mixing angle t-ta tells you the amplitude of the escalation.
STFC-RAL-CR03 R61: And the second term oscillates up and down through the distance.
STFC-RAL-CR03 R61: So you start with a new E, then it becomes a new, then it becomes a new E again, new again through yoga, according to where you are.
STFC-RAL-CR03 R61: And the frequency of this selection depends on the error. So, many cases, turns out, just having two… considering two neutrinos is enough, and for this reason, the metric is broken down like this.
STFC-RAL-CR03 R61: Where you see this one only mixes the 2 and 3 states, and this is relevant for construct neutrinos.
STFC-RAL-CR03 R61: This one is a rotation, again, in two-dimensional, maybe relevant for solar neutrinos, and this one is for reactor matrinos
STFC-RAL-CR03 R61: And,
STFC-RAL-CR03 R61: several… that much we know, several things we don't know yet. So one thing we don't know is delta CP. You see, there are three mixing angles, and one parameter here is called delta CP. That's the only term, that if it's non-zero, it makes the matrix imaginary, and that leads to CP violation. So we know CP is violated by the quarks.
STFC-RAL-CR03 R61: We don't know yet if the string is violated, which is the code you would expect to violate, because they're violated.
STFC-RAL-CR03 R61: We know close to nothing about the value of delta's B.
STFC-RAL-CR03 R61: Theta to 3, so the value of theta23 is very close to 45 degrees. We don't know whether it's exactly 45 degrees, and that means anything.
STFC-RAL-CR03 R61: Or it's a bit more, or a bit less, in that sense.
STFC-RAL-CR03 R61: So this is called the problem… problem of whether P23 is maximum or not.
STFC-RAL-CR03 R61: And then the hierarchy, so…
STFC-RAL-CR03 R61: There are three maxes, and one and two, and then three. We know two of them are very close, and the third one is more separated. We don't know whether the separated one is higher or lower in X.
STFC-RAL-CR03 R61: Because we know the mass three things, but we don't know the absolute mass. And that's the other thing, the absolute mass, you don't know.
STFC-RAL-CR03 R61: And also, we don't know whether it's the same as the antigenotrino, which makes it an ironic part.
STFC-RAL-CR03 R61: It's a little blue icon.
STFC-RAL-CR03 R61: And it's on the exotics.
STFC-RAL-CR03 R61: Okay, the last thing for introduction is, I just want to show you, the Trinos come in a very wide range of energies, from microelectron volts, to 10 to the 20 electron volts. This is the highest particles ever measured by the Trinos.
STFC-RAL-CR03 R61: And, so you have an enormous spine of energy, and the flux of them drops.
STFC-RAL-CR03 R61: But the frustration increases with the energy, the detection fraction.
STFC-RAL-CR03 R61: So that's important to realize, and so there's a possibility to see all of that.
STFC-RAL-CR03 R61: Something like that.
STFC-RAL-CR03 R61: Okay, so machinophysics is working in other different areas, and I'll talk about the first one, which is the probability.
STFC-RAL-CR03 R61: So…
STFC-RAL-CR03 R61: Double beta decay, so beta decay is this process where you treat a nucleon, you become a proton, and you get out an electron and a treatment. Dalbone beta decay simply means that you have a nucleus, and by chance.
STFC-RAL-CR03 R61: In the nucleus, two neutrons decay at the same time.
STFC-RAL-CR03 R61: Independent.
STFC-RAL-CR03 R61: So it's just a very rare process that exists in this kind of model. It's, in fact, the rarest process that we ever measured.
STFC-RAL-CR03 R61: And that's this one. And you get two electrons out and two neutrinos out, because it's two beta tapes.
STFC-RAL-CR03 R61: The one we're looking for is neutrino less double-betically, which looks the same, except no neutrinos come out, because one of the antineutrino that comes out transforms into a neutrino and is absorbed, because I'm making an antineutrino is the same as it's not getting a neutrino.
STFC-RAL-CR03 R61: So this process is the one we're looking for, the trainers.com. It violates its undermodel, because it violates left on number, 22 units, because the trainer becomes an antilateral.
STFC-RAL-CR03 R61: So, how do you look for it? You cannot see the neutrinos, do they escape, all you see is the electrons, and you measure the total energy of the two electrons. So, in the normal allowed process, the energy of the two electrons is continuous, because some of the energy is stolen by the neutrinos. So, the energy spectrum looks like the blue line here.
STFC-RAL-CR03 R61: Whereas in the neutral aspect of the decay, all the energy that is free by the decay, which is constant, goes to the electrons, and it's maximal, because the three ends equally nothing. So, the signal should move like a spike at the end point.
STFC-RAL-CR03 R61: And that's what you're trying to measure. This is your reducible background, and this is what you're seeing.
STFC-RAL-CR03 R61: Why we look for this process that's not being observed yet is because,
STFC-RAL-CR03 R61: It would be very nice, it would prove that the neutrinus matter tropical, it would explain in a very natural way why the mass of the neutrinus is so small, which is the mystery, and it would also explain why we have matter, you know, in the matter of the universe, which is not a big mystery, so it's kind of a very important thing to discover.
STFC-RAL-CR03 R61: There are a number of nuclei that can undergo neutrinos of the liquid change, and we're going to look at those.
STFC-RAL-CR03 R61: So, one of them is called Kamlan Zen, this is located in Japan, and this one lives at Xiemann.
STFC-RAL-CR03 R61: As a kind to this further decay.
STFC-RAL-CR03 R61: The echo looks like this. Basically, it's a very big balloon that contains the heating scintillator.
STFC-RAL-CR03 R61: And then inside, there is a smaller balloon, this one, which also contains the crystal acre, but also the semen.
STFC-RAL-CR03 R61: Okay? The idea is that if one of these nuclei of Xeon undergoes neutral metal decade, two axons come out, they make light, it measures total energy, and so you see an event with nothing coming from the outside, and the energy matches the endpoint, and then you have this called the Schrodinger's double binoc.
STFC-RAL-CR03 R61: Okay, so these have been taking data since the 2012 or so in different phases.
STFC-RAL-CR03 R61: They measure the total energy released, and it kind of looks like this. So you have this… this portion on the left is the irreducible background of the two neutrino battery. This other bump is some radioactivity stuff that has a problem with contamination with silver. The stock they're looking at should appear here, at the end point.
STFC-RAL-CR03 R61: Okay?
STFC-RAL-CR03 R61: So, I think this blue line here is what the signal would look like if it was there. Anyway, you don't see any access of the data over the Monte Carlo, so they haven't seen it, and then all they can do is to set
STFC-RAL-CR03 R61: An upper… a lower limit on the half-life of the decay, which is 102 to 26 years.
STFC-RAL-CR03 R61: So, you know, the age of the universe is 10 to 11 years, so this is an enormous… Awesome.
STFC-RAL-CR03 R61: haven't seen.
STFC-RAL-CR03 R61: Another such experiment is called water, this is hosted in Italy, and this one, rather than xeno, looks at tellurium. It's another of those nucleators that do it. So what it does is it has a bunch of these cubic crystals of tellurium.
STFC-RAL-CR03 R61: And so, each of those crystals.
STFC-RAL-CR03 R61: Again, if one of the nuclei decays, you will have two electrons thrilling here that release some energy in the cube.
STFC-RAL-CR03 R61: And then how do you see it? The trick is that you carry the tube to extremely low temperatures and really heavy.
STFC-RAL-CR03 R61: Such that, if the electrons are released and absorbed, there will be a change in temperature.
STFC-RAL-CR03 R61: And that's what you measure. So imagine how precise you have to be
STFC-RAL-CR03 R61: To measure the change of temperature due to two electrodes.
STFC-RAL-CR03 R61: It's crazy, crazily sensitive. So this is called a blunt.
STFC-RAL-CR03 R61: The track looks like this. Basically, you have a big… Breach?
STFC-RAL-CR03 R61: And inside, there is a smaller, more powerful fridge, which is colder, and inside there is a smaller, more powerful fridge, which is colder, like a bachelaska kind of thing. And the innermost one is the coldest one. That's the one that carries one kind of material to tell me it healthy. This is, in fact, the coldest
STFC-RAL-CR03 R61: You know, meter cubed in the universe.
STFC-RAL-CR03 R61: Okay, they've been taking data since 10 years or so.
STFC-RAL-CR03 R61: The data looks like this. Again, all you can do is measure the total energy released in these kilometers.
STFC-RAL-CR03 R61: This sloping curve over here is the reducible background. This is where your signal would show up, and then there is a million lines that are all identified
STFC-RAL-CR03 R61: You know, with amazing energy resolution, I'm lucky to have activity.
STFC-RAL-CR03 R61: Again, they see no excess.
STFC-RAL-CR03 R61: This is a zoomed in the region of interest. There is this big peak, which is understood. The signal would show up here, but there is no excess.
STFC-RAL-CR03 R61: And so, we set the minimum 35 years.
STFC-RAL-CR03 R61: And very briefly, this will, in the future, will be graded from a factor called qubit.
STFC-RAL-CR03 R61: It is similar, but rather than tellurium, you have molybdenum as your choice of isotopes. You have a crystal of polybdenum at low temperature. The advantage is that molybdenum can be made into a simulating material, so now you have two observables. You have the temperature change, but also some light is emitted.
STFC-RAL-CR03 R61: By the simulator, and there is a light detector at the top, so you also have a light simulator.
STFC-RAL-CR03 R61: Coincidence.
STFC-RAL-CR03 R61: And this is what they look like, well, this is the cube, and this is the successor of the topic.
STFC-RAL-CR03 R61: This is another experiment. This is located in China.
STFC-RAL-CR03 R61: You see that these have gone to different phases with increasing amount of mass, because this is what we find, created detectors.
STFC-RAL-CR03 R61: It's hosted in this laboratory, which is extremely deep.
STFC-RAL-CR03 R61: Underground, so very well screened from capitaries.
STFC-RAL-CR03 R61: That one looks like this. It is a xenon time projection chamber, so it's a TPC.
STFC-RAL-CR03 R61: Where, again, material is xenon, and if the nucleus decay, you will release some charges, and that's what you detect. And it's a dual phase, so the bottom portion is liquid xenon, and top portion is gases xenon.
STFC-RAL-CR03 R61: That's the spectrum they measure. You see it's the same story for all that. You measure a total spectrum.
STFC-RAL-CR03 R61: This is the usual background, this is some other stuff. Let's see that would show up here, they see nothing, and they said only attempt to spend 4.
STFC-RAL-CR03 R61: See, so I can.
STFC-RAL-CR03 R61: The last one I want to mention is Super Nemo, because this one is pretty detailed.
STFC-RAL-CR03 R61: Because, you see, all the ones before, all you could do, you had one observable, which is the total energy.
STFC-RAL-CR03 R61: Supernimo does it differently because it does see two separate tracks. The others do not have any tracking.
STFC-RAL-CR03 R61: In this one, you do see two electrons, and you do see that they count on the same spot.
STFC-RAL-CR03 R61: same vertex, you need to see that they emit at the same time, and you measure the individual energies rather than the sum. So there are many more observables. And why that's important is because if the material as double dip decay happens, you still need to know how it happens, what is the underlying mechanism of Feynman diagram.
STFC-RAL-CR03 R61: So, simplest version is what I mentioned before, is just exchange a light neutrino, but there can be
STFC-RAL-CR03 R61: more exotic things, like the right-handed parts of the root interaction, or the emission of the myron, which is an additional particle, and so on. So to figure out what is the mechanism, you need the angular distribution, which our supermo can provide.
STFC-RAL-CR03 R61: So the background looks like this. See, in the other experiments.
STFC-RAL-CR03 R61: The source and the detector is the same thing. We have a cube, which is the source and the detector.
STFC-RAL-CR03 R61: But in this one, the two fractions are separate.
STFC-RAL-CR03 R61: So the source is over here, which is a very thin foil of the isotope of your choice, which shoots out the electrodes.
STFC-RAL-CR03 R61: And then the electrons move in a tracking chapter, so you see two tracks of magnetic curvature, because there's a magnetic field, so another electrons are positors. And then they reach a wall at the end where there's a perimeter, which locks up scintillator with the PMT at the top.
STFC-RAL-CR03 R61: So the golden event would look something like this. This is the foil, one electron, the other direction, the parameters, and the sum of the two electrons giving you the endpoint.
STFC-RAL-CR03 R61: And you see, this gives you many handles to reject the background differently than just based on the average.
STFC-RAL-CR03 R61: Supernova was very slow to start, and wasn't that, you know, 10 years ago.
STFC-RAL-CR03 R61: Anyway, in April, they've taken the first beta-beta candidate, it looks like this. Two electrons very clearly coming out. Unfortunately, the sum of the two ends, which is 1.56, which is not the endpoint.
STFC-RAL-CR03 R61: But I know that it is valuable.
STFC-RAL-CR03 R61: Enough time is up here.
STFC-RAL-CR03 R61: Okay, so we will now be slightly, shifting topics and talking about, long baseline experiments.
STFC-RAL-CR03 R61: So here, the method is a little bit different. So what we usually start off with is a neon-mutino, a muon-antino beam, and then we look at how this beam oscillates over a long distance. And actually, at the conference, we had, nice talks from all of the currently running long baseline experiments, so from T2K and Novaq.
STFC-RAL-CR03 R61: One experiment which actually just started data-taking, and that's Juno. They started taking data at the end of August, and then two of the flagship up-and-coming experiments, HyperK and JUL.
STFC-RAL-CR03 R61: So with this technique, usually, we need a near and a file detector, so the near detector is there to constrain the system optics and to understand the initial dream composition, and then the file detector is where we measure the acceleration parameters.
STFC-RAL-CR03 R61: We started off with a nice talk on conventional, neutrino beams for these experiments.
STFC-RAL-CR03 R61: So normally, how we produce neutrino beams for this type of experiment is we start off with high-energy protons, and then those protons bombard and extend the graphics target.
STFC-RAL-CR03 R61: And what happens is protons interact in the target, and all sorts of hadrons come out, and then we use magnetic horns to focus those haddroms, and we wait for them to decay in flight. And it is from these in-flight decays of the hadrons that we get the neutrino beam. And typically, we can control the polarity of the current of the horns, so if we focus positively charged.
STFC-RAL-CR03 R61: will give us a neutrino beam, and then negatively charged ones will give us an antineutrino beam. So we have the option to switch between the two.
STFC-RAL-CR03 R61: Now, another thing that was mentioned in that talk are the commonly used techniques for producing machino beams. So, one of the concepts is the so-called off-axis beams.
STFC-RAL-CR03 R61: So if we look at the kinematics of the hydron decay that produces the neutrino, if you look at pions, we will see that the energy of the outgoing neutrino depends on its angle with respect to the incoming pione direction.
STFC-RAL-CR03 R61: So, if we position our detector at a certain location, we can actually get a narrow band beam, and this is typically what the experiments that use this technique do. So we position our detector at such a location that the beam is narrow, and it's at the right energy to observe an oscillation maximum.
STFC-RAL-CR03 R61: And this is what T2K has done.
STFC-RAL-CR03 R61: Now, another technique that is also commonly used is that of the adjustable beamline configuration. So this is, for instance, done with the NUMI beamline. So what they have the capacity to do is to change the location of the target. So if they move the target a little bit more upstream, they end up directing the lower angle and higher energy particles to the horns.
STFC-RAL-CR03 R61: And when we focus those higher energy patterns, they give us a higher energy neutrinopoly.
STFC-RAL-CR03 R61: So you can see, with the new beam light, we have this option to run within the high energy, medium energy, and low energy configuration.
STFC-RAL-CR03 R61: Another technique, which is also sometimes used with,
STFC-RAL-CR03 R61: neutrino beams is that of an all-axis Y beam.
STFC-RAL-CR03 R61: And this is what the LBNF and Dune experiments will be using. So, the reason why a wide beam is interesting is because you can see here, we can span, more than one oscillation maxima. So, by observing two oscillation maxima, or even more, we can gain some sensitivity in terms of oscillation parameters.
STFC-RAL-CR03 R61: Now, another area that this talk talked about was the challenges that long baseline experiments are facing as they ramp up to higher beam power. Because higher beam power means that all the beamline components need to be manufactured in a more sturdy way, and we need to think very carefully about cooling, the cooling requirements. Of course, we want higher beam power, because this gives us more statistics over a shorter span of time.
STFC-RAL-CR03 R61: Actually, a very nice achievement, which was demonstrated and talked about in this talk, and which is relevant for us at JARP, is that done by the technology department here. So the technology department at JARP has manufactured a new gene pump. So this is a target for the T2K and hyperK experiments that will be able to operate at 1.3 megapoles. So this target had to be redesigned in terms of the
STFC-RAL-CR03 R61: Cooling capacities that we've used so far.
STFC-RAL-CR03 R61: Because of the high power that we're going towards. And this has been produced at a technology department in Dall.
STFC-RAL-CR03 R61: As you can see here, we also had a visit from the spokesperson of Supermane, Professor Nakata Masayoki. He came to the technology department to see this target, and actually now it has been shipped to Japan.
STFC-RAL-CR03 R61: So what we are hoping is that we will be able to install this new target in the summer of 2026, and then all future T2K and HyperK data-taking will rely on this new design.
STFC-RAL-CR03 R61: So this was a little bit of an introduction on mucino beans, and now we will be talking about news from the NOVA experiment. And I talk about that…
STFC-RAL-CR03 R61: So this is located in the United States. You have this beam of neutrinos, beam of new moons.
STFC-RAL-CR03 R61: They park from Fergula, they run, what, 800 kilometers, and they arrive at the fire detector in Minnesota, so you have a near-detector and the fire detector.
STFC-RAL-CR03 R61: The two detectors, the near and the far, are functionally identical, except the far one is much bigger, so it is the size of a person.
STFC-RAL-CR03 R61: And what the factors look like is there are arrays of these strips of plastic simulator, so when a particle comes in, it produces light in the strip, and the light is confined in the strip, because the edges are coated. And then there's a fiber that runs through it and captures the light and carries it.
STFC-RAL-CR03 R61: your PFT.
STFC-RAL-CR03 R61: So this, unlike all the other neutrino detectors, which are usually deep underground, this one is on the surface.
STFC-RAL-CR03 R61: Which means that it's…
STFC-RAL-CR03 R61: all the time receiving a very large number of cosmic rays. As you see, this is an example on the event display where the beam should be coming from the left. All these tracks, which are vertical, are actually cosmic fields. Actually, this shows how good the detector is, I mean, you can see how nicely you see all the tracks.
STFC-RAL-CR03 R61: The background is very good, because despite this background, it manages to eliminate it without the need to go underwork.
STFC-RAL-CR03 R61: And so they measure, oscillation parameters. For example, they measure this theta23 angle. That's the one that is close to 0.5, but we don't know exactly. So you see they measure sine squared theta23, it's very close to 0.5, but it could be a bit less or a bit more. That's the likelihood of the values.
STFC-RAL-CR03 R61: And it changes that we did incorporate constraints from other experiments, so we don't know exactly. We also measured delta M3, 2, the mass splitting of the 3 and 2 mass eigenstates.
STFC-RAL-CR03 R61: Actually, so for example, this block shows the global measurement of this N32 parameter, see here. These are different experiments, NOVA, ISK, T2K, SuperK, minus, so on. There is general agreement between them, and NOVA gives the most stringent, the smallest error, smallest error.
STFC-RAL-CR03 R61: Bonnie?
STFC-RAL-CR03 R61: Yes, now on T2K. So, T2K is another one of the baseline finishing experiment. We have a baseline of 300 kilometers, roughly, so we produce the beam on the eastern coast of Japan, the JPEG facility I mentioned, and we use this for practice beam technique.
STFC-RAL-CR03 R61: And then the five detector is super familiar. Of course, the Nobel Prize-feigning, world-famous genetic detector.
STFC-RAL-CR03 R61: And you can see we have a need detector complex, which characterizes very precisely the initial build structure and constrains our systematics.
STFC-RAL-CR03 R61: So, in terms of the oscillation analysis, we had a nice talk at the conference presenting T2P's latest oscillation results. I just wanted to demonstrate here everything that goes into an oscillation analysis. So, we need a flux model. The flux model relies on the simulation, but also it's tuned to external carbon production data.
STFC-RAL-CR03 R61: We need a cross-section model, and this comes from a cross-section generator, so this is something that theorists and terminologists developed for us, but again, it's tuned to external and also internal cross-section data.
STFC-RAL-CR03 R61: We need models for our two detectors, and then, of course, data from the near and from the bi-detector. On T2K, we always do two analyses. One is in the frequencies, the other is in the Bayesian probability framework. And the two needs to converge for something to be reported as a result.
STFC-RAL-CR03 R61: Now, I quickly wanted to mention the selection at the nerve detector, so what kind of data do we use at the nerve detector, and also mention our internal program of cross-section measurements for T2K.
STFC-RAL-CR03 R61: So the milk detector facility that we have is actually multiple. So we have more than one meal detector. All of these detectors are only, 200, just over 200 meters away from the production point of the beam.
STFC-RAL-CR03 R61: So no oscillations have happened yet. And you can see these are at different, off-axis angle positions. So we have the English detector, which is not magnetized, it's on axis. Then we have a Bagascian baby mind. This is 1.5 degrees off-axis. This detector includes a water target, which is interesting, because the power detector, has water as the target material. So this gives us some nice constraints with this type of template.
STFC-RAL-CR03 R61: And then we have the ND280 detector, which is at the same off-axis angle as supercarbioca. And this is where we select events for our oscillation analysis from. And you can see this detector has a very complicated modular structure, but this is also its strength, because it allows us to perform all kinds of measurements.
STFC-RAL-CR03 R61: The selection of events at the mere detector is as follows. So you can see, if you look at the energy of the C2K beam at MV280, around 600 MeB, most of the interactions are charged current quasi-lasting interactions. So the final diagram for these, you can see the neutrino interacts with,
STFC-RAL-CR03 R61: a nucleon as a whole, so it doesn't, result in internal structure within the, within the nucleon. But you can see we also have some, charge current interactions with resonance production. Here is the Feynman diagram for this process. So often here, we will have pions in the final state.
STFC-RAL-CR03 R61: And then also we could have some deep inelastic scattering with many particles in the final state.
STFC-RAL-CR03 R61: When we prepare samples for the oscillation analysis, we don't quantify them in terms of the interaction type and interaction vertex. Because these three fibrin diagrams, these are showing a single free nuclei. But of course, don't forget the nucleons are inside the nucleus.
STFC-RAL-CR03 R61: And the detector can only see what leaves the nucleus, so there's many sorts of final state interactions undergone by these products.
STFC-RAL-CR03 R61: So, we classify interactions in terms of the final stage topology. So, we have CC0 events. These are events where in the final stage in the detector, we don't see a PIR.
STFC-RAL-CR03 R61: So most of these events are charged when quasi-elastic, but for instance, we could have some resonant events when the pine is absorbed in the nucleus, and it looks like CC0 pi.
STFC-RAL-CR03 R61: So we have CC0 pi, CC1 pi, and CC are the samples for an oscillation analysis.
STFC-RAL-CR03 R61: And then, in terms of the cross-section results that we do, I also wanted to flash this. So we had a talk on cross-section results that I gave for T2K. So here you can see T2K's data-taking program for cross-sections. Starting from 2013, when we published the first analysis, all the way up to now.
STFC-RAL-CR03 R61: And here you can see all of these CC0pi, CC1 pi, and other types of interaction channels, and you can see all the publications that we've made since then. Even if we look at the last year, you can see multiple publications in the last year.
STFC-RAL-CR03 R61: So we have a very rich program of taking these measurements, and these always feed into the phenomenological models for machine learning interactions.
STFC-RAL-CR03 R61: Now, as a file detector, the selection is a little bit different. The file detector is, of course, a water transfer detector, so they look for the rings.
STFC-RAL-CR03 R61: So if we have a diffuse ring, it's going to come from electron-neutral interactions, because electrons scatter more in the tank, in the water tank. And sharp rings come from neuronuclear interactions.
STFC-RAL-CR03 R61: So you can see we have 6 samples, so the samples are split by neutrino and anti-neutrino mode, whether the ring is neuron-like or electron-like.
STFC-RAL-CR03 R61: And then we also have two additional samples for charged current interactions with a pione in the pione state. And we identify this pione by the presence of a second Cherengko ring from the decayed electron. So for these cases, we actually have two charenco rings.
STFC-RAL-CR03 R61: So these are the samples that we used in the oscillation analysis. Now, in terms of the data presented at the conference, you can see this was T2K length 1 to 11, so we had 2.1 times 10 to the 21 POT in neutrino mode, 1.6 times 10 to the 21 in anti-mutrino mode.
STFC-RAL-CR03 R61: Keep in mind that we've collected more data since then, and actually, a lot of this additional data is with the upgraded in Hector, so this is something that will come out in due course. Analysis is on point.
STFC-RAL-CR03 R61: But for what was shown at the conference.
STFC-RAL-CR03 R61: Here you can see our result for the delta CP parameter. So this is the parameter that would signify whether CP violation occurs when it doesn't. If you look at the delta chi-squared distribution as a function of delta CP, you can see that we prefer a value of delta CP around minus pi over 2.
STFC-RAL-CR03 R61: So this would be for maximum CP violation. You can also see that CP conservation is excluded with a 90% confidence level. So if you look here at the 90% confidence level, and we just about exclude the values of delta CP0 and 180, which would be the two CP conserving values.
STFC-RAL-CR03 R61: We also measure other oscillation parameters. So here you can see for delta M squared P2, what, our result is on the left-hand side.
STFC-RAL-CR03 R61: Here you can see, again, 1 sigma, 2 sigma, 90% continuance level limits for normal and inverted mass ordering, because we don't know what the true mass ordering is. And then also, if we look at the
STFC-RAL-CR03 R61: sine squared theta 2, 3, this is the angle where we don't know in which octland it lies, if it's 45 degrees or not. So this is our result. You can see the T2K data doesn't resolve the octland yet. So we have some probability that it lies both over and under the value of 45 degrees. So T2K data on its own right now can't resolve this octland yet.
STFC-RAL-CR03 R61: Another thing that we reported on is our joint results with Supercannio Hande. So T2K detects these beam neutrinos, but Supercannio Hande, our fire detector, can also measure aducci neutrinos.
STFC-RAL-CR03 R61: And the reason why it's nice to combine those two results is because atmospheric neutrinos span the same energy range as T2KB neutrinos, and then on top of that, they span more energy at higher energies.
STFC-RAL-CR03 R61: But the fact that they share some of the energy range, and the fact that we use the same detector to detect those two types of events, makes them attractive to be combined in a single analysis, and then increase the detection sensitivity.
STFC-RAL-CR03 R61: So here you can see, for the Super Camille Conde atmospheric data, we're using SuperCome around 4. So this is the data taking period 4. You can see there's a lot of additional data available for us to use later on, and you can see which T2P data we use as well.
STFC-RAL-CR03 R61: So the results here… well, first, in terms of the…
STFC-RAL-CR03 R61: analysis that we performed. So, for this very first measurement, the neutrino flux models are not correlated yet, so this is going to be done for the next example.
STFC-RAL-CR03 R61: The detector models are fully correlated, as they should be, and then for the neutrino interaction models, we correlate them for the energy range which is shared between the two data sets.
STFC-RAL-CR03 R61: So, 0 to 2 GB, energy, here we correlate the interaction model, and we use the constraint for T2K Smith factoring.
STFC-RAL-CR03 R61: And now here, to show the results. So,
STFC-RAL-CR03 R61: on the left-hand side, for delta N squared 3, 2, you can see that becomes a similar result as that for T2K only. So combining super K and T2K, this is the red curve. Obviously, SuperK on its own is not very sensitive to this parameter, and then combining it with T2K gives us a curve which is just slightly sharper than the T2K one.
STFC-RAL-CR03 R61: A similar sensitivity at the moment.
STFC-RAL-CR03 R61: And then, if you look at the sine squared theta 2 free parameter.
STFC-RAL-CR03 R61: So here, the 2K result had a slight preference for a value which is over 45 degrees, and the Super K1 had a slight preference for a value under 45 degrees, so actually now we are at a stage where we are sort of compatible with maximum mixing at the moment, at the current statistics, at least.
STFC-RAL-CR03 R61: And then another thing for the delta CP value, so both T2K and super K favor a value of delta CP of minus pi over 2, so maximum CP violation. And we can see also here, there's a clear enhancement in sensitivity, so the T2K curve is the blue one.
STFC-RAL-CR03 R61: T2K plus super K, the red one. You can see this is a sticker pair, and we have an overall exclusion of a delta CP conserving value of 2.5 sigma. So this is where we are at the moment.
STFC-RAL-CR03 R61: in terms of the patterns for normal ordering, mass ordering, we have a rejection of inverted ordering at 1.2 sigma, and here we expect a big improvement when we add more super-K data that we have. Because actually, super-K data, because atmospheric neutrinos travel through the Earth, and depending on the Zenith angle, they travel different distances to the Earth, the matter effects give us a lot of sensitivity
STFC-RAL-CR03 R61: connect for the week.
STFC-RAL-CR03 R61: So we expect improvements here.
STFC-RAL-CR03 R61: So, in conclusion, so what was shown were oscillation results T2K on its own, where we can exclude CP conservation at 90% continence level. And here, we are really looking forward to this future analysis, where we can use the ND280 update data.
STFC-RAL-CR03 R61: And then for the joint result, we really want to use more of the Super K data, which is available, and that's going to be the next iteration of the joint phase.
STFC-RAL-CR03 R61: Now, I've mentioned that we want to use more of the upgrade data, so I briefly wanted to mention T2K's new detector upgrade. And this is something where the NAL group played a very big part in terms of detector commissioning and integration in the global data system.
STFC-RAL-CR03 R61: So here you can see the original MD280, which I mentioned. This is this highly modular detector. And if you look at this sub-detector, POD, you can see what we did. So we took COD out, and we installed Super FGP.
STFC-RAL-CR03 R61: So SuperMGD is a fine-grained detector, made of, one cubic centimeter, plastic cubes.
STFC-RAL-CR03 R61: And there's actually 2 million of those. So this has been assembled by hand, and this detector gives us unprecedented resolution and tracking thresholds as well. So you can see it has been placed in the middle of the pod location, and then up and down from it are two high-end projection chambers. And then this is all encircled with time-of-life detectors.
STFC-RAL-CR03 R61: So, commissioning test happened in 2023 and 24, so this has been completed, and we are taking data with this, graded detector.
STFC-RAL-CR03 R61: So, here you can see some of the nice event displays which we received, during the commissioning period. So, first one thing to notice, all of these events, if you look at the timing of the events, the timing aligns with the beam bunch structure that we sent to the detector. So, we didn't know that these are events from our C2KB.
STFC-RAL-CR03 R61: And then here, in every case, you can see the event display, and then we're zooming into the interaction vertex. So if you look at the top figure, you can see the nice resolution that we have for events where the interaction occurs off from what we think is a correlated nucleon pair.
STFC-RAL-CR03 R61: So not a single nucleon, but two nucleons, so we have two protons in the final studies.
STFC-RAL-CR03 R61: And then we also have a long view, in fact.
STFC-RAL-CR03 R61: So these are nice events that give us a handle on these so-called 2P2H processes.
STFC-RAL-CR03 R61: Then at the bottom figure, here, another interesting event. So here we have a pione in the final state. We think this is a pione candidate event, and then you can see also a Michelle electron from the pione decay.
STFC-RAL-CR03 R61: And then lastly here, what we can see is an event with a short proton track and a long muon track, and actually this long muon track is at a very large angle with respect to the incoming beam direction. So with the previous high beam detector, we actually had no detector acceptance for these high-angle events. Now we do.
STFC-RAL-CR03 R61: So again, this is very nice for us.
STFC-RAL-CR03 R61: In terms of what this data is going to allow us to do, this upgrade data, so we had a talk on this, first of all, it's going to reduce the tracking thresholds for protons.
STFC-RAL-CR03 R61: So every neutrino interaction is going to happen off from a neutron in the detector, and there's going to be a proton in the time of study. But often, we don't see those protons because their energy is too low.
STFC-RAL-CR03 R61: That used to be the case with the original MD280. Actually, we used to have to have the proton go through four layers of the fine-grane detector in order to… for it to be reconstructed as a track.
STFC-RAL-CR03 R61: Because the time gain detector consisted of scintillator bars, so one bar could only give two positional informations, and we need three
STFC-RAL-CR03 R61: for a single point. So the track needed to go for 4 layers, whereas now it's enough for it to go through two layers, because every hit is a cube, so we have the full 3D information for a single hit. And you can see that this moves the threshold from around 450 MeV per C for those photons down to 300 MeV per C.
STFC-RAL-CR03 R61: And then when we select our signal for oscillation analysis, we are having a much purer signal than what we used to have, in terms of pure CC quaselastic interactions.
STFC-RAL-CR03 R61: Another nice thing that a Super FGD will allow us is that to detect neutrons. So what we can do now is we can search for the secondary interaction vertex of the neutron before it's thermalized, and then by looking at the distance between the primary and the secondary vertex, we can figure out the kinematics of the neutron.
STFC-RAL-CR03 R61: So here you can see one of the events displayed during the commissioning period for one such interaction. And here you can see, so this is the incoming muon neutrino, the primary interaction vertex. We have a pion and a muon tract.
STFC-RAL-CR03 R61: And then the second millivertex of the neutron is displaced by roughly 12 centimeters, and this corresponds to a kinetic energy of the neutron of around 30 mp.
STFC-RAL-CR03 R61: So again, this is something that will be incorporated into the oscillation analysis.
STFC-RAL-CR03 R61: Another attractive feature is that we will improve our selection of electromagnetino events with Super FGD, so a large contamination for electromagnetector are events with photons in the final state, because the photon pill produces, and if we only see one of those electron repository, it looks like a single electron.
STFC-RAL-CR03 R61: Well, with Super FGD, we can actually distinguish between a photon and a single electron or a positron, because we can look at the energy deposition in those cubes, and for a pair-produced photon, the energy deposition is going to be double that
STFC-RAL-CR03 R61: As from a single, electoral position.
STFC-RAL-CR03 R61: So this is something that we can, yeah, look forward to with these new data sets. So now, just a little bit about.
STFC-RAL-CR03 R61: So now we're talking about the two big experiments of the future, which are hyperK energy.
STFC-RAL-CR03 R61: And the hypercane will be hosted in Japan. It has four pieces, so you have the laboratory where you shoot the beam, like Amazon explained. Then you have the mirror detector, which is the same respiratory duplicate that we just described. Then you have the fire detector, which is called
STFC-RAL-CR03 R61: And as usual, you measure the beam at the beginning, and you measure the beam at the end, and you see it's changed.
STFC-RAL-CR03 R61: And then there's one additional one in hyperlink, which is called the intermediate detector.
STFC-RAL-CR03 R61: So you have one more, you know, along the line, just actually closer than here.
STFC-RAL-CR03 R61: So Hardware K, of course, expands on the previous experiments, so this was Camiakande, then Super Kamikande was B, which is 8 times bigger of usual volume, and now Hardware K is B, which is, again, 8 times bigger of the usual volume.
STFC-RAL-CR03 R61: just scaling the duct, but being very conservative on the structure, so it's this big, water transfer tanks.
STFC-RAL-CR03 R61: line with PMTs, or none of them are over 20,000 PMTs. These are large half-meter diameter PMTs, and also different types of
STFC-RAL-CR03 R61: MultiP, multi-p modules.
STFC-RAL-CR03 R61: Detection principle, I don't have to explain again. The trail comes in, it makes, trying to light, because it's moving… charge particles moving faster than light in water.
STFC-RAL-CR03 R61: So, on the wall, it projects a ring, and by the… how the ring looks, you can tell if it's a movie or a movie, right?
STFC-RAL-CR03 R61: Thomas I explained before.
STFC-RAL-CR03 R61: I'll say a couple words about this intermediate detector, because it's a new thing.
STFC-RAL-CR03 R61: So there are two ideas here. The first one is that the near detector of PDKE is rather different from the target vector, and this makes things very complicated, because you try to compare the two measurements, but they have different system activities and targeted, so…
STFC-RAL-CR03 R61: So instead, this intermediate detector is basically a mini camera. So it looks just the same as a fire detector, except it's much smaller. That's the first evidence.
STFC-RAL-CR03 R61: The second idea is that this one is movable. It's mounted, basically, on an elevator that moves up and down.
STFC-RAL-CR03 R61: You know, sit in a 50 meter.
STFC-RAL-CR03 R61: Yeah, yup, that is the following exact.
STFC-RAL-CR03 R61: The beam is actually passing under here, under the cross of the earth, under your feet, so when you're at the bottom-most position, you're close to the beam center. When you move up, you move further away, so you span different top-axis angles.
STFC-RAL-CR03 R61: And like Thomas have explained before, by doing a different access angle, you probe different energy portions of the beam.
STFC-RAL-CR03 R61: I know this is kind of clever, because depending on where you are, you know what the energy is.
STFC-RAL-CR03 R61: Without having to measure it.
STFC-RAL-CR03 R61: I just flashed hierarchy will do some very nice results. For example, this is the measurement of the delta's P-value. So this is the true value of delta's P, which we don't know, although there are hints that it's somewhere around here. So this plot shows, you know, after 10 years, with how many sigma
STFC-RAL-CR03 R61: can we exclude that that's P is here? So, you see, if that's P is maximally violated, so you're here or here, then the sigma is very large, and you can have a 9 sigma level.
STFC-RAL-CR03 R61: That is not zero. But if delta CP is close, then it's much harder to measure, but the signal is very, very small.
STFC-RAL-CR03 R61: The Holy Grail for this detector, one holy grail.
STFC-RAL-CR03 R61: is the nuclear decay, which is the reason why they were originally created this fast. Because these are big amounts of water, and the water you have hydrogen, hydrogen is just a proton, so there's lots of protons in the sand. And if one of those protons decay, like many great unification theorists predict.
STFC-RAL-CR03 R61: Then again, you will have a spontaneous release of energy in the tank, with nothing coming from the outside.
STFC-RAL-CR03 R61: So that's never been measured. There are many hypothetical ways in which the problem can be K, and for some of those, hyperK is better, and for some of those, dume is better. HyperK is better when you produce
STFC-RAL-CR03 R61: you know, a charged particle that the main channel. So with these two channels, proton goes into positron by zero, or into 3 molec.
STFC-RAL-CR03 R61: hypercase vector, and this shows that as a function of the year, you know, what half length you can reach, order of 10 to 34 years. That's incredibly large.
STFC-RAL-CR03 R61: Right?
STFC-RAL-CR03 R61: The timeline for hierarchy looks like this. Basically, in only 2 years, we will start taking data, really next, near the quarter.
STFC-RAL-CR03 R61: And the status cover has been excavated fully now. This is actually the largest man-made cover in the world. You can see the first one here.
STFC-RAL-CR03 R61: enormous. And, we're building it now, and many PMTs have been tested.
STFC-RAL-CR03 R61: June?
STFC-RAL-CR03 R61: He's a big complementary slash competitor.
STFC-RAL-CR03 R61: Experiment that has a very similar physics reach, but a very different technology and way it does it.
STFC-RAL-CR03 R61: Very interesting.
STFC-RAL-CR03 R61: So, June, is in the United States.
STFC-RAL-CR03 R61: Again, you get a beam from Fermilot, and now it travels a very long distance, 1300 kilometers, just under gear, not even a cube from the Earth.
STFC-RAL-CR03 R61: And he detected in South Dakota by the Parliament.
STFC-RAL-CR03 R61: So, like, also, as I've mentioned before, the beam in HyperK is nano-band. It's almost monochromatic in Trino Beam at 600 LV, whereas the dual beam is wideband, it spans, you know, 4GBs of energy, it's much wider.
STFC-RAL-CR03 R61: Because you want to have different energies, because you want to be able to see the first and the cycle distillation maximum.
STFC-RAL-CR03 R61: The distance is fixed, but you change the energy, so you change the oscillation.
STFC-RAL-CR03 R61: The main attacker looks like this. I will not go into the details, other than the 10… I mean, the point of the attacker is always to measure the beam before it does reach.
STFC-RAL-CR03 R61: But I will just mention this, thing, which is a movable detector, just like the one in HyperK, but only to enhance the complementarity of the two detectors. The HyperK one moves vertically.
STFC-RAL-CR03 R61: And the D1 moves, for example.
STFC-RAL-CR03 R61: Other than that, same idea, and it stands in terms of axis angles around those rails.
STFC-RAL-CR03 R61: And then you have the fire detector. So what the fire detector looks like… first of all, it's modular, like hypertage, so you build the module, and then when you have more funding, you build more modules to make it bigger. It's a stage
STFC-RAL-CR03 R61: Did they process?
STFC-RAL-CR03 R61: The technology is liquid argon TPC, so this is a time protection chamber in which the medium is liquid argon at low temperatures.
STFC-RAL-CR03 R61: And there are two ways to do it, either horizontal drift, where the charges you produce are drifted horizontally onto the cathode.
STFC-RAL-CR03 R61: or vertical drift, and both of them will be done in stages. The first one they would make is the vertical drift, as I understand.
STFC-RAL-CR03 R61: It goes on the street.
STFC-RAL-CR03 R61: The physics rich, so… The idea is like this. You shoot new muse.
STFC-RAL-CR03 R61: You check that they're new using the ear detector, and then at the fire detector.
STFC-RAL-CR03 R61: You measure if some new leaves have appeared, because they are specific.
STFC-RAL-CR03 R61: So you look for new ease in the product market. And then you do the same with anti-natured. You shoot anti-new neighbors, and you look for anti-new E's.
STFC-RAL-CR03 R61: And now you compare matter and antimatter behavior.
STFC-RAL-CR03 R61: Like, and if the oscillation is different for a neutrino and anti-neutrino being, that's when you know there is CP population.
STFC-RAL-CR03 R61: So, these new E's that appear in the fire detector are rare by the day stacker, but they will be abundant in these future experiments. So, for example, this shows the spectrum of new leads that will be predicted to appear in the fire detector, and you see the statistics is several hundreds of deaths.
STFC-RAL-CR03 R61: for neutrinos, and a midlife for granting the trainer, because the anterior tranos are more difficult to produce, because they're more dismay of matter.
STFC-RAL-CR03 R61: And this shows, again, what the dune can achieve, so it tells you, as a function of the years of running, what is the resolution that you can achieve on these galaCP parameters. You see, they can
STFC-RAL-CR03 R61: They probably can't be later, but they can do very precise measurements, like, within 10 degrees.
STFC-RAL-CR03 R61: Or the true value of that speed.
STFC-RAL-CR03 R61: So what we're doing is now, it's supposed to start… so why Hybrid Cave will start in 2028, June will start one year later, the last quarter of 2029. We also have excavated caverns.
STFC-RAL-CR03 R61: In order to store stuff.
STFC-RAL-CR03 R61: And the last thing I want to mention, there are two protogue modules that have been tested at CERN, both for the vertical and for the horizontal drift, and this picture kind of shows the exceeding quality of the imaging that you can obtain.
STFC-RAL-CR03 R61: And we can look at algorithm technology.
STFC-RAL-CR03 R61: Yeah, let's move.
STFC-RAL-CR03 R61: Oh yeah, just briefly to mention one final long basin experiment. It classifies as a long basin experiment. It's a Juno, so this is the Jiangben Underground Mutrino Observatory. So it's a liquid scintillator detector, 20 kilotons, located in southern China, you can see.
STFC-RAL-CR03 R61: And the reason why this is interesting is we had a talk from this experiment just before they started data tape.
STFC-RAL-CR03 R61: So,
STFC-RAL-CR03 R61: you can see their physics goals, how to measure, to determine the neutrino mass ordering. And when we were showing the sensitivity plots for, let's say, Kuper K, we always had those two curves, if mass ordering is known, or if it's not. Well, dual could be one of the experiments that tells us the mass ordering, so that we have a better sensitivity. You can see the other thing is they want to precisely determine the oscillation parameters, these three ones here.
STFC-RAL-CR03 R61: And then, in terms of where the neutrinos will be coming from, Juno is roughly 50 kilometers from two nuclear reactors.
STFC-RAL-CR03 R61: And we call it JUNO, it's the Juno tau detector. And you can see, they also are, in the process of constructing Juno tau, which is going to be at the position pretty much next to one of these nuclear reactors. So this they can use sort of as a near detector. And then you can see the position of Juno is at the optimal distance for observing the anti-electron-neutrino
STFC-RAL-CR03 R61: orthopedics.
STFC-RAL-CR03 R61: In terms of the reach that Juno can have with reactive neutrinos, on the left-hand side, you can see the expected sensitivity for determining the mass ordering, and I think this is… so they expect pre-sigma sensitivity in six and a half years data taking if they just use reactor neutrinos.
STFC-RAL-CR03 R61: But they will also have access to atmospheric materials as well.
STFC-RAL-CR03 R61: And then, again, just using reactive machinos, if they want to determine the oscillation parameters more sensitively, you can see the values on the errors of the oscillation parameters from the PDG-published value in 2024, and only 100 days of JULO data taking actually improves on most of those. So, Julo can really provide very precise
STFC-RAL-CR03 R61: measurements.
STFC-RAL-CR03 R61: And you can also see, actually, when the talk was given at the conference, Jura was, preparing to start a day that they need Saturday, I think, on the 26th of August.
STFC-RAL-CR03 R61: Now, the last topic switch is to talk about astrophysical neutrinos. So we had a couple of talks covering these topics. In terms of the
STFC-RAL-CR03 R61: astrophysical neutrinos. The reason why they are interesting is because these are the highest energy neutrinos that we see, and also the highest energy particles, really, that we've observed.
STFC-RAL-CR03 R61: The running detectors… there's three running detectors that use the Chernko technology. So these are IceCubes, which is located in the South Pole.
STFC-RAL-CR03 R61: Cay and Spainet, which is in the Mediterranean Sea, and it has at least two, instrumented areas, Arca and Orca, which are off the coasts of, Italy and France.
STFC-RAL-CR03 R61: And then there is also the Baikal gigaton volume detector in the Baikal Lake in Siberia.
STFC-RAL-CR03 R61: And so the techniques for all three of these experiments are largely the same. We always have these strings, which are suspended in the water, and then these are instrumented with optical sensors.
STFC-RAL-CR03 R61: optical modules.
STFC-RAL-CR03 R61: So, we had results presented from IceCube. First of all, in terms of extradalactic neutrinos.
STFC-RAL-CR03 R61: So IceCube has actually identified two sources. If you look at the map of the sky here, you can see where these sources are located. So these are two point sources for external arctic neutrinos. However.
STFC-RAL-CR03 R61: these sources are not bright in high-energy gamma rays. So if you look at the telescope information, we don't see any bright light coming from here. So probably the candidates for what these sources are would have to be some kind of arctic galactic nuclei, which are obscurved, so which are not bright in high-energy gammas, but they can be bright in X-rays.
STFC-RAL-CR03 R61: So, now analyses are ongoing to see what kind of obscured galactic nuclei could correspond to these sources. And they are actually looking at different neighboring galaxies in the southern hemisphere, and performing analysis to see if any of them correlate with these sources, and they are seeing some pretty significant evidence for some correlation.
STFC-RAL-CR03 R61: So this was for extragalactic neutrinos. Also, IceCube is searching for galactic neutrinos. So if we look at our galaxy, the Milky Way, along the galaxy plane, you can see the top figure here shows us the optical gammas and the gamma rays. So this is a map of the galactic plane in those gammas.
STFC-RAL-CR03 R61: But then, if you look at the bottom-most map, this is a map of our Milky Way plane in terms of the observed neutrinos. And actually, the different colors, the color map corresponds to the significance for observing neutrinos coming from this plane. So the way how the analysis is performed.
STFC-RAL-CR03 R61: IceCube is comparing different diffuse emission models.
STFC-RAL-CR03 R61: to a background-only hypothesis, using its data coming from the galactic plane. And they are seeing some 4.5 sigma significance for identifying neutrinos from the galactic plane, and now they are combining cascade and track events for increased sensitivity and to be able to claim discovery of these galactic neutrinos.
STFC-RAL-CR03 R61: For galactic neutrinos, there is some complementary evidence from other experiments as well. So, Paris also observed a 2.2 sigma excess.
STFC-RAL-CR03 R61: in the galactic plane. KM3Net is not sensitive yet, because if you look at the sensitivity curves of KM3Net are curved, they are above from the ice cube forms, but some preliminary analysis from Baikal also show some excess in this plane. So, it seems like we are reaching some kind of complementarity there for the evidence for galactic materials.
STFC-RAL-CR03 R61: Another interesting feature of IceCube that was reported on was the fact that IceCube can actually determine the neutrino flavor.
STFC-RAL-CR03 R61: So, depending if an event is a cascade, or a burst, or if it has a double burst structure, we can figure out if it was an electron, muon, or found neutrino. So ICU can actually generate these maps of the flavor composition for all of the neutrino candidate events that reach it.
STFC-RAL-CR03 R61: And it's currently the only experiment that can do this for astrophysical neutrinos, but other experiments might have this capacitor later.
STFC-RAL-CR03 R61: And then, as the unexpected, so we also had the results reported from KM3Net Archa of a very high-energy event. So this is a very bright new one, which crossed
STFC-RAL-CR03 R61: the detector, which is in the Mediterranean.
STFC-RAL-CR03 R61: almost horizontally. And this event, you can actually see it here. If you look at the number of triggered PMTs on the y-axis, and then on the x-axis is the Zenith angle, you can see a single event with a huge number of triggered PMTs, much more so than anything else. So this came from a neutrino with a medium energy of 220 pentaelectron volts.
STFC-RAL-CR03 R61: So this is the highest energy, I think, particle that we've ever observed. And this was reported in Nature beginning of this year.
STFC-RAL-CR03 R61: There are no sources identified for this neutrino yet, because the angular arrow is still quite large, and actually no similar events were observed by IceCube or Vital, so there is currently a physical level tension between AM3Net and these other ongoing active experiments.
STFC-RAL-CR03 R61: Then, in terms of the future, well, for Chenanco detectors, we've had a couple of other talks at the conference as well. We had a talk from P1 and Strident that I'll discuss briefly, and then we also,
STFC-RAL-CR03 R61: had some mention of going to even higher energies and using detectors which use other techniques. So some may be radio frequency techniques for high energy particles.
STFC-RAL-CR03 R61: Now, P1, so this is a future experiment, which is in the design stage, and it would be located in Canada, off the coast of British Columbia. So it would be the Pacific Ocean Neutrino Experiment, and you can see a similar technique as what, let's say, what ISP is doing. So we would have these 1 kilometer long booming lines, every line with 20 modules.
STFC-RAL-CR03 R61: Currently, PY Frequency is entering the demonstrator stage, where they want to deploy a single booting line, and then the full detector will be from 2030 onwards. I mean, in the future, it's still…
STFC-RAL-CR03 R61: A bit in the future.
STFC-RAL-CR03 R61: One interesting thing about the technique that they're developing, so for the optical modules, every optical module, in addition to the multiple PMTs, will also contain two acoustic receivers. And the idea is that P1 would like to have a very precise timing resolution, on the order of 1 nanosecond. So, a precise timing resolution requires a relative positioning
STFC-RAL-CR03 R61: from neighboring optical modules, which is on the order of 20 centimeters or so. So they are saying that this timing positioning is going to come from these acoustic receivers, which are coupled directly to the glass of the optical modules.
STFC-RAL-CR03 R61: So they are currently working on the calibration of these acoustic receivers to figure out what kind of position sensitivity they can have.
STFC-RAL-CR03 R61: Another thing that they observed, they have deployed some of these modules in the water, and they actually encountered this issue of biofoundering. So basically, what they saw is that the outward-facing optical modules developed, you can see some growth on them, which led to a 65% drop in efficiency. But this wasn't observed for the downward-facing modules. So they are looking at some techniques for a biofouling
STFC-RAL-CR03 R61: Putting to mitigate this.
STFC-RAL-CR03 R61: You can see the location has been determined, potentially, for this detector, and it's just off the coast of British Columbia. You can see the ground there is a detector roughly 2.6 kilometers, 2 degrees water temperature near the ground, and low currents as well.
STFC-RAL-CR03 R61: So, the future for P1, what we were told is they are looking for a module of opportunity in the spring of this coming year, 2026, to deploy this single module with the optical detectors.
STFC-RAL-CR03 R61: So this was for the P1 experiment, and then another experiment that we, heard about was the Trident experiment. So Trident is a similar idea as P1, it would be in the South China Sea. And again, this is another future experiment where they are currently in the stage of
STFC-RAL-CR03 R61: fine-tuning the detector configuration, in terms of the spacing between the lines that hold the optical modules, and also how many PMTs per module would be needed, and what PMT size.
STFC-RAL-CR03 R61: And you can see they're using this hybrid digital optical module structure, so they want to use a combination of PMTs and also SIPMs, which I think SIPMs were not used before for these types of detectors.
STFC-RAL-CR03 R61: They can also identify a position which, from the physics perspective, is very favorable for the detector, and you can see it here in the South China Sea.
STFC-RAL-CR03 R61: This position has been approved by China, but other countries also lay claim to this position. So this is a slightly politically challenged position. This was also discussed at the conference.
STFC-RAL-CR03 R61: And this pretty much brings us to the end of the content summary, so thank you, everyone, for your attention.