Hello, um, yeah. So we're approaching 2 o'clock. So I guess we'll start now. Thank you very much for joining us for our 1st Ralph student lecture.
Um. We are very honored today to have Dr. Anna Hollen with us.
Who is a very valued member of the Uh Physics department uh, and also superb elites our neutrino group as well. And I'm not just saying that because she's my line manager um. So without further ado, Anna is his talk to us today about neutrinos and unlocking the mysteries of the universe.
Um hello! Hi um.
Welcome, everyone.
So.
I think, because this is a you know, a student lecture. I will sort of go through the history of neutrinos first, st and what they are to, you know, create an overview.
Um. You know.
Of uh over there. Okay, I'll I'll pick this one.
Um.
Okay, so.
You may or may not know, but neutrinos are fundamental, and they complete our family of the fundamental particles that we know, and often the standard model.
So you can see we've got clocks here, and we've got our leftons here, and so we've got 3 neutrinos.
That we know of an electron. You know Munich and town neutrino.
And they're sort of the brothers or sisters of those.
3. Leptons.
And um, they are very interesting to study. Uh, we know that there are 3 active neutrino types.
Um, and we also know that they have the antiparticles, the anti-neutrinos.
And um. Many people don't realize.
But neutrinos are everywhere. They just pass to everybody all the time they're produced in in space, in stars, um in the atmosphere. So every moment in time.
Thousands and millions of them just go through every one of us. And so that's why we.
Those particles. So you've got a little picture of little ghosts here because they never interact or almost never interact. And so studying them is very hard because of this, but makes it very exciting.
So.
Where do they come from? So I already mentioned.
Solar neutrinos. Um. So this is a picture of.
The sun, taking using neutrinos.
By the Super K experiment. So uh, it's a very interesting picture, because you can see that we really see neutrinos coming from the sun.
Um.
Then the atmospheric neutrinos. There are Geo's produced in the case in the earth.
Um super nova neutrinos uh get produced. Nova explodes. They may be dark matter. Neutrinos.
For example, if neutrinos are dark meta candidates.
Um.
I think.
And then we can also produce.
Neutrinos ourselves.
So.
You know, very scary proposition. Neutrinos are produced in abundance and nuclear explosions. We can make neutrino beams.
So that's a much more controlled way of making between us.
And then we also have um nuclear reactors.
That also produce neutrinos all the time.
So this is um. I think the last 2 is sort of.
What we use when we study neutrinos in experiments. A lot.
Um. So why do we want to study them?
So um neutrino solutions.
Um. It's a phenomena that we discovered uh recently.
And um, it's the only sign of physics. We understand that model that we definitely know of. Um. So it's like a telescope onto new physics. And so this is why we want to. Um, you know. Study neutrinos. In Neutrinois there are many outstanding questions, for example, how heavy are neutrinos? So the mass. Um! Are there new symmetries of nature?
Um that we haven't discovered yet.
Um? Could it be an explanation?
For the matter, and the matter is rich in the universal. Why, we even exist. In the 1st place, why is there more matter than antimatter, so neutrinos could.
Points away. In discovering this there could also be, as I mentioned, a candidate for dark matter. There may be other unexpected discoveries, so the history of nutritive.
Examples where we discovered things that were unexpected.
And so it's a very interesting field.
So.
I'll tell you a little bit of puff history.
So how do we even find out about neutrinos? In the 1st place? So um, sometime in the 1920 s. Or so, um.
People.
We're observing beta decay, and they originally thought that.
It was a simple process that you know the electoral will be emitted.
Familiar that was undergoing a change from a neutron to a proton, and.
People were able to measure the spectrum of those electrons being emitted.
But you know, if this is the case, then you would expect one discrete.
Uh, it's a sudden energy, what? And I I actual fact. What was observed? What is.
Distribution of um of electrons. So people didn't understand why there was such a distribution and not.
You know just one peek at the one discrete energy.
And so um.
It was um.
You know something that really puzzled them, and.
Um in a letter in Argentina. So this is the uh sort of a.
Screenshot of this original letter.
Uh in German uh desperate remedy was proposed.
Uh by. And he basically suggested that it wasn't just an electron that was being produced. In fact, there was another particle.
A neutrino. Now we know it's an anti-neutrino.
That was escaping at the same time, and so that was taking some of the energy, some of the momentum away, and therefore we were getting this continuous distribution.
For the you know, for the Beta K. That we're observing um.
And so here you have the actual process.
That's happening in reality.
Um.
And uh, you know.
Neutrinos what, as I just mentioned, you can't see them. So, for example, chamber uh. All you could see was, you know, a recurrence.
And so the outgoing election. But.
You couldn't see anything, you know where you would expect a 3rd particle to be.
So it was sort of, you know. Um, something that.
Was postulated but not proven um. And the reason for this is because the cross section of nutrients interacting is very small. So they're extremely unlikely.
To interact.
Um. So people wanted to.
Um detect the neutrinos obviously, and prove that they really exist.
And so the what's this project, poltergeist, which is actually, you know, the experiment that was set up.
To detect the neutrinos and succeed it. But this um experiment had a bit of a crazy history, so um they called it poltergeist, as in, you know, ghost particle um. And they needed a large flux of neutrinos. And so the 1st thing they thought about was, um, let's use nuclear bomb.
And you know just um.
Have a basically a detector drop at the moment of the explosion, 40 meters alongside the explosion into a hole so that you know you could see a big flux of neutrinos, and so you detect them. And this is, you know, quite crazy and dangerous. And also it's not a very controlled experiment in itself, you know. How do you then pick apart your results?
Um. So then it was decided to use a nuclear reactor instead, which was a much more reasonable um solution. And uh, so let's experiment. The writers and count experiment then decided to use.
This uh um. You know a telephone detector at the Savannah.
Eb.
We have a new nuclear site and.
What I were trying to do was they were trying to capture.
Invest beta decay neutrinos. So basically um.
Where? Ah.
Basically.
Rather than the beta decay that you know you had when the users are produced.
You would actually have an antenna from the reactor.
Hetapron, and that would create a positron.
And the neutron.
So it's the investment decay process.
And you can see that the text that I had here was ah, an interesting design. So there was.
Um cadmium loaded water.
Um level here and here.
And then there was a big scintillator here, so liquid scintillator that would produce light.
Uh.
You know, when he saw something, and the Pmt's photo tubes would read out the slides and cause a signal.
Um! And then there was a lot of shielding around.
Um.
So these are the results of this experiment.
That proved that.
You know that the neutrinos have been observed? So um! You see, that was published in Nature in 1956.
And you know there are some pictures of the tank, the Texas tank and the water tank. And so the way it would work was that you had the neutrino from the reactor. Come in and um, and then it would. You know, you can see this here on this 1st plot on the left.
And it would interact.
Um with a proton.
And.
Um, it would produce uh a positive one. But obviously a positron is anti matters, so it would quickly annihilate producing 2 gamas um, and so you would observe a signal from the 2 gamas.
And then um, you know this.
The resulting neutron was sort of, you know, Bounce, about.
Until itself it resulted.
Uh in capture on cadmium, and that created some neutrons that you could observe a certain time later, and so on. The right, you can see, sort of an event display.
From that paper where you can see that.
There was some, you know, 1st a signal.
In 2 of those layers, and then 5.5 um microseconds. Later there was a second signal, and so that was a total sign that you had actually seen a neutrino. And so they had discovered the neutrino.
Um.
So there was a very important step in proving that they actually exist.
Rather than I. Just a particle that's postulated out of desperation.
Um. Then, as I mentioned at the very beginning.
We know that there are actually several neutrinos. There's a neutrino that we know about as well.
And um. So people wanted to find those.
Um. And so it was hypothesized in the 19 forties.
And that this existed, and then it was found in this experiment.
Uh for the ags experiment um by later on, Steinberger. And so what they did was.
They actually made a neutrino beam.
So the impacted. Some protons.
Onto a target.
And when they hit the target uh the they've created.
A bunch of pions. Um! So hard, Jones, that were emanating.
Uh. It created the neutrino beam, and then they were able.
Observe those neutrinos in their.
So that was a pretty amazing experiment for the time, if you can imagine um. So a little bit more detail about this.
Um.
So.
Basically, the question was whether neal neutrinos are actually a separate type of neutrino or not from electronos.
And so, you know, there was this question here whether this was really the case.
And so, if they were the same, you would expect roughly the same number of electron events and your nutritional events to be observed from that beam. But.
Um. They knew how electrons look like. Because when you know, when you see a neutrino neutrino, you expect to see an electron. And they knew how. Electron looked like from from um.
A test view experiment. Uh, here's only one display for these.
And then um! They found events.
In the data with neutrinos, with a neutrin.
Where you can see in the stock chamber this.
That starts here there's nothing. And then suddenly it appears.
And you can see this me on track.
And again he does nothing, and suddenly it appears, and there's a meal check.
And again nothing and suddenly immune appears.
So, you know, these were clearing neutrinos. They were different from those events that you could.
So they could tell that they were different, and, in fact, they expect they found 34 such events.
Um. They only expected about 5 uh background.
Leon. Um events from you know, Cosby. Radiation.
And um, so they would have expected about 29 electron events. Um.
But um! I you know they only found 6.
So from that it was very clear that the different type of neutrino and that had been shown.
Um. So the final neutrino.
That people wanted to find was the.
Cell neutrino.
And so this was actually observed for the 1st time very recently in 2,000. So you know, it's not that long ago, only 25 years ago that the Donut experiment officially observed this neutrino, and published the results.
And um.
The doughnut experiment.
Did this? Um?
In a clever way. So they made a town neutrino beam.
Um. They built this experiment where they impacted.
Um 800 gb, proton. So these are very high energy.
Photons onto a thick tank and plate.
And from this they would expect about 3% of neutrinos to be neutrinos.
Um, and so the web. Then, you know, sense. All of this was sent to magnets, and so on. So they had a neutrino that was going.
To their detector.
And the sector was in motion type detector. The reason you need such a fine-grained detector is because.
You know, if you look here at those lines here that.
Measurement lines is this is the scale given. So the vertical line represents it says, 0 point 1 mm.
And this line represents 1 mm. So what happens is that as soon as your tow is produced in the town event.
Um, you have basically the case very, very quickly. And so what you get is a kink where the tow is turning into a muon.
And then obviously.
You have.
Neutrinos escaping everywhere. Uh! Where the king happens.
Um. So you know this is a touch outside of town, you know. Events.
And this is what people expected to see and what was seen. And so this was proof that we had seen town Neutrinos town neutrinos were also later the opera experiment.
So um, I sort of evaluated to.
How neutrino interactions.
Work already in words, but just to, you know, make sure that you know people understand. So um, when you have any come in, it will interact.
Weekly um, either. Via um, you know a boson.
Was that person, and that will produce.
Then a corresponding Lepton charge, Lepton, that escapes.
So when you have election it, you know. Come in. You'll get an electron.
Uh, and me only on, and so on.
And then you have the, you know, the nucleus or the system against which.
Um. It's a you know.
Is because, I guess which it hits, and you've got some outgoing.
Um, you know, system that usually it depends on the type of event, whether it's very energetic or not. What you get in this system here.
So. Um, so this is an example, for example, from the Nova experiment.
Where you have, you know the Neutrina.
And you have some um, you know, protons going out this way and then and big electron coming out that way. So an electron creates an electromagnetic shower and then detector. And so you can really see the sort of showery shape.
Um when you have a meal.
You know you will have a meal being produced, and again some recalled proton.
Um. But, Milan, you belong thin tracks of just one hit.
To sell.
And then you can have unusual events. So this is when a neutrino comes in and the neutrina goes out so as as 0 is exchanged. And so when does that? Says your opponent is exchanged.
You actually don't know what the energy of the neutrino was, because you're not able to measure.
Those systems here you can find out what the original energy was of the neutron. But here you don't know, because the neutrino came, interacted, left some energy in the detector and.
Went on its way. So in that case you have, you know, showy type.
Um events. And and for many analysis these are considered background to what we want to see, just because.
You know we can't tell the energy of the neutrino.
So um! I alluded.
To neutrino oscillations earlier. And so I want to tell you a little bit more about this.
Um. So you know the neutrinos that we actually see the electronum they actually made up of different mass states. And this is a quantum physics. Phenomenon. So um, essentially, what happens is that those flavor states.
Um mixed via this.
Big giant Pms, matrix.
You can even make it bigger if you add additional terms which I have not done here in this superposition of those 3 mass eigenstates.
So you know.
This is a.
Uh, you know this thing. You can sort of picture it like this that you know they have. Every one of the neutrinos has got some amount of mass.
From the different mass States.
When you detect it. Um. And so what happens is that when the neutrinos travel through space and matter um, there was a probability associated with that of what type of neutrino will detect.
So if you make a 100% militar.
For example, so.
Like here. In this value we have an initial neon neutrino. It turns out that, depending on its energy.
And L, which is the distance or baseline that it has travelled.
You have a certain probability that it has.
Changed into a town neutrino, or changed.
Neutrino, or it has stayed as a as has survived as a neon neutrino.
So you know, these are the kinds of things that allow us to measure oscillations and investigate when neutrinos do.
Um. So you know the certain.
Um moments in space, and you know, and the energies for the neutrinos, where you can see that.
You know those probabilities are maximized that.
Things will have oscillators away. And so these are usually the points.
Where we want to put our experiments at.
Or, you know, change the energy of the beam, or whatever to make sure that we actually are able to maximise the sensitivity of our experiments.
Um.
So the other thing that we can do is measure.
Mass differences. So um oscillation don't have sensitivity to the absolute Latino mass.
Um.
But we do have sensitivity to the mass differences, so we can find out what the differences between.
Um, you know the second and 3rd mass eigenstate. But the differences between the 1st and second state.
And so different experiments measured those different states. And this plot is a little bit complicated here, because you've got 2 sides to it.
So we know.
From experiments on experiments.
That.
Um.
And 2, the second mass seconds, that is heavier.
Then m. 1.
So that we know for a fact.
But we do not know whether M. 3.
It's heavier or lighter than this doublet here.
So the mass difference here is very small. It's 5 times 10 to the minus 5.
But here is much bigger. It's it's too old of magnitude, bigger.
Ah, but we don't know whether this is.
Lighter or heavier than this doublet.
So you know, in the neutrino physics, everybody, you know, speaks of normal mass ordering on normal hierarchy. That's when we have this sort of natural situation. That. Okay.
Um in nature, in many other places.
Um, you know, but um.
Because normally we would expect, like the sweet to be.
Heavier than 2, and so on. But we also can speak of the inverted mass ordering, or the inverted hierarchy. And this is when you have this situation reversed.
And so um.
This is something that people are trying to measure right now, and we haven't got the answer yet.
Um so.
Um. We have measured many of those parameters.
That I mentioned here in this.
Matrix.
Um. So you know, this is from the particle group.
You know you've got all those values that have been measured.
Um. I think I'll now. These are quite recent, but they have measured all of these, but we always say whether it's inverted order or normal order, because that affects the number that we measure.
Um. And so things that we want to know.
Um.
Is, for example, uh the Cp violation phase.
So this.
Parameter, here.
In this matrix. We want to measure this because that is the thing that will tell us.
Whether we are able to explain the matter or anti matter, asymmetry in the universe. A lot of models rely on this.
To be large.
For, for.
Or the theorist to make sense. If it's not large, or if it's close to 0, then.
You know it's back to the drawing board for many of those theories. Um, then you have a seat at 2, 3, maximal. So this angle of how much.
Those neonatrinos mix with a tau neutrinos.
You know, and whether the disappearance maximal that actually could be a hint to a new symmetry of nature if it is maximal. And so people want to measure this, and they want to know whether it's something else. Or if it's, you know, non maximal, um. So people are really interested in those questions, as I mentioned already, what's the Nitrina key?
Um. People are also looking for other neutrinos.
For example, sterile neutrinos.
Um, which would not be um.
What we know, the 3 neutrinos that we know, that are active.
They would not um.
Basically interact via the weak via force.
But they would interact via Osc.
This is a tax. Please.
Thank you.
Um. Okay. So uh, what was I saying? Yes, um. So if there are, neutrinos would not interact via the weak force.
Um, so we would not see them the usual way, but they would mix with the other States.
Via um.
Probabilities, oscillation, probabilities. So you could imagine that you know the oscillate into another.
So our neutrino as well as the other ones. And so what would happen is, it would.
Ah! Modify the probabilities.
Of the nationals disappearing and the other ones appearing. So we can sort of have an indirect handle on neutrinos, and whether they exist via doing all those measurements.
And then you know what is the absolute mass of the neutrino? Those are questions that I'm not going to focus on.
Too much in this talk. Um!
Because the studio physics is just so vast. But we also want to know those kinds of questions.
Um. So how do we do those.
They should. Oscillation experiments. Um.
So the gold standard um is.
Using long baseline neutrina.
Um. So it's very simple.
Um. We make a beam of neutrinos.
And we send it to the F. And.
They go through a detector at the beginning.
And then they I go for a second detector far away.
Um many hundreds of kilometers away, and so we can.
Measure.
What's.
Composition, the beam.
Before Venetian's oscillators.
And then, after they oscillate.
And from this we can um deduce all those parameters that we want to measure.
So. Uh, for example, those 2 experiments that I'm going to talk a lot about doing and hyper care. Um, you know, they, this is.
The main bread and butter of those experiments.
So.
A little bit of how we measure. So this is like a simple example of how we would do this.
So if you have um.
Uh an expectation of what your beam looks like.
Um without oscillations, without neutrinos, having oscillated.
Um, and based on your knee detector observation.
But then you actually um.
Have another expectation of whether insurance have oscillated.
You can, you can. From this you can directly measure.
Your oscillation parameters. So this is just using a few flavor approximation. But, for example, the probability of.
I'm going, you know, having oscillated to an electron neutrino.
Would be as a function of the angle, the mixing angle between them, and then this arrow e parameter, and the Delta M squared, which is the mass squared. Difference between those 2 um new one and new. 2 mass eigenstates.
Um.
So from that, you could basically, this formula would basically mean that if you take the ratio of this.
Oscillated, not oscillated.
You sort of get this sort of shape.
So this is what the oscillation maximum occurs.
And basically, the depth of this step tells you.
How big your Max, your mixing angle is. So you know it could be maximum mixing. Then it's the depth of the dip gets bigger and bigger, and if you have time squared.
Is given by the position of the death. So you know, this is the sort of thing we do when we measure the oscillation parameters. Obviously the world we have is um. You have seen this Pms matrix.
It's got more parameters than that, and so on. And but this is a simplified version of what we do, and it's actually been quite a good approximation over the years, anyway, until we started measuring things more precisely many experiments. We're just using the 2 flavor approximation to determine the parameters.
So um.
How do I? Can neutrina beam.
So I think just a few more words on this, because I already mentioned this.
You know a modern neutrino beam is made. You send.
Some protons onto your target. The target is usually made nowadays out of a graphite rod or some graphite.
Fins. Um, that uh, you know a bit about the meter. Also.
And then um, that produces pions and chaons.
And those get focused by magnetic horns.
So those magnetic horns actually quite important, because they mean that your flux of neutrinos really increases a lot.
Some experiments have 2, some have 3.
Um. But you know you just send those and accounts to this phones.
And that focuses them, and then, when they decay in this long decaye afterwards.
Um. You have a quite a focus of neutrinos.
Going forward in the direction of your detectives.
Um! There was an interesting thing here that um.
When you.
Switch. The polarity of the horns.
You switch your phone.
Um. You know, we reverse the phone. Then you can change which ions you focus. And normally, we focus.
Um 5 classes, and that makes a neutrino beam. But you can actually, instead, reverse theology of the horns.
Focus of time minuses, and then you get an Antrim. So you know, we have both.
Um, so this is very interesting.
So current experiments.
That we have an Nova taking data right now. These pictures. It all kind of looks small. But actually, for example, Nova.
It's absolutely massive. Ah.
The father sector is 16 meters tall and 16 meters wide and 60 meters long. So it's absolutely huge. And you know why it's huge is because what I'm explained before you have to have really big detectors to cash enough neutrinos to even do any measurements.
Um.
And you know you can see that. You know, when a nutrient interacts.
You know he comes in, and it will produce some.
Uh some activity. Then the detect.
Uh, and that uses the um new beam that is being sent to Ashwa from fam.
And.
Then we have Ttk, and that's located in Japan.
And that uses a Jpark beam, and that has got.
Um, and then d 2 80 um suite of nerd test.
Measuring things like cross sections, and so on. Very precisely. And then, um, you predict your fire detector. And for the fire text that people use the K detectors. So this is an absolutely huge again, this picture is tiny, but you can see this is a boat.
On the water there. Um! And this has got 11,000 multiplier tubes.
That, uh, you know, really beg to see me. It's just centimeters across each.
And it's about 40 meters full and 40 meters wide.
Um.
So, you know, you can see those detectors are really huge, and the measuring things that you know disappearance, and which is, you know, sensitive to those parameters that I alluded to. They measure neutrino appearance.
Um. So we're looking for those electrons.
That come from the electronics interacting. And this is sensitive to this Cp violation phase Delta, that can tell us about the mathematics machine in the universe.
And also the octet of theta, 2, 3.
So whether it's above.
Oh, below 45 degrees.
Um. So some um plots here to show you what they actually see. So this is in the file detectors. So this is Sonova. Um, you can see. So Nova was. It's not shown here the unassolated spectrum, but you can see the oscillator spectrum and the best fit.
Which is um in purpley pink. Here.
And then you have the data. So you can see how.
Precise and.
Exquisite those analyses that you can predict what you're going to see. And then you you observe it. It's just absolutely amazing. And those neutrinos have gone through 800 kilometers to the earth.
And we were able to predict it and analyze this data. Um, so.
You know, this is what Nova sees with 10 years of data.
Um, this is what uh it sees in terms of elections.
So if you recall um. There were almost none in the beam that was produced at Firmin up.
Suddenly they've appeared 800 kilometres further away. And suddenly you have all those electroneers appearing. They are in different groups of whether they are low, Pid. So low confidence or.
Or high Pid. So these are ones that are the most signal, like events.
Uh, and you can see that.
You know.
Antonio, be neutrino beam.
So again, you've got complementary in there as well.
And so this is really interesting data. So oh, one thing I haven't mentioned is that when you have an anti-neutrino beam.
You have a flux of anti-neutrinus, reduced roughly by a factor of.
3, so it takes the 3 times longer to accumulate the same amount of data with Antineutrinos.
So this is why all the experiments initially run a lot with neutrinos.
But obviously the Antinutigunners are so interesting, and they also give you a lot of sensitivity to data. Cp.
Um. So everybody needs to run with anti-neutrinos, too.
So um.
Um.
Spectra. So these are ctk spectra. So these are some, you know events. So ctk, as I mentioned, is a water chart of detector.
And it sees events differently to Nova. So it doesn't see those.
You know, even so that showed. But it showed it actually sees big water rings that happen when you have a particle going faster than the speed of light inside a medium. So the electron that gets produced by the neutrino.
It's traveling faster than the speed of light.
In water.
And so you get this sort of cone, the light cone that gets produced, and which you can detect with fault to multi tubes.
Um. And so you can tell a neon an electron.
Because the mutant rings are much sharper.
Me on soft, heavier. And also there are no um, you know. Electrons will interact a lot with other electrons, you know. So you know the election events are very diffuse, whereas the rings from Muons are very sharp, and so you can also detect those.
Um.
And so, you know, you can see, for example, this is one ring, so neutrina mode.
Wondering, neon neutrino. So you can see the data versus what your expectation is.
Um.
You know, and this are your actual neutrinos. So again you can see. And so this is, for example, the anti.
Um neutrinos as well, so you can see again.
Um. You know, Antonio, um, electron is appearing. Um.
In an antenatal young beam.
So, you know, these are really interesting things again, you know, exquisite measurements. But those change.
The Texas.
Um, and he has some results.
Um for the parameters that we measure so um.
I was just gonna go briefly over those. But basically um.
You know that some of the plots that I've shown often are those how many events electro events you expect to see.
The anti neutrino sample versus the neutrino sample, depending on your data. Cp value. So you have.
Different delta Cp values. So those dots here, for example, here actually correspond to minus pi, 2 for delta cp, delta, Cp goes from 0 to 2 pi, or minus pi, 2 pi, depending on how you draw your.
Access. But um! You can see the Ttk really likes.
This value, and you know the.
Point where you put the point. It also depends on the 2 3.
Angle. Um! And here you have a big plot. Um! You can see that.
Teacher has a side preference. Um.
For higher value, but for the upper Octant.
After that, 2, 3. And you know, data. Cp, it likes this maximal value. Obviously, because this point is right there on the edge.
Um, but actually the.
0 delta Cp. Is not excluded at higher than about 2 sigma, so it's still allowed.
Um, and obviously in Tdk also has a slight preference for the normal mass ordering.
Um.
Um, no, by results. You can see a similar plot here.
Um, you know. But Nova actually has. The data is sort of more in the middle. So it's not here on the edge, but it's more in the middle, so it sort of clashes a little bit.
Uh with 2 k um.
Uh it's got. It's newest results from a few weeks ago. Um, you know, they have the highest precision. Um, as for a single experiment of just one and a half 10 uh. So it's essentially become the best measured uh parameter um. And here you can see sort of, you know, in this part the space of data 3, 2, and.
You know. 2, 3.
Um, you know, when Nova is compared to all the other experiments, so you can see they all sort of agree with each other, but there are.
You know, it's not quite clear whether we have maximum mixing or non-maximal mixing from.
Um.
And this is the Nova result in a different phase space. So this is C that you see versus delta Cp, and I think this is the one that people are really interested in.
At the moment. All, you know, all the new experiments really like to show this, because um, it's um. It's what everybody wants to know whether we have.
Ma, you know, maximal mixing, and whether we have data cp, nonzero. And this is for the novel hockey or normal mass ordering.
And this is for the inverted path and.
This plot is sort of uh interesting as well.
Because um.
So the new result here is in purple.
Um. So they were, showing that they were consistent with the old result, which was in blue.
Um. But then you can see here the red.
Is Tk. 500,022.
And so you can see that this was causing a lot of excitement.
Um. You know among physicists that.
Ttk in the normal mass ordering doesn't really seem to overlap with a Nova limits.
Um very well.
Um. So people are saying, Well, why do they not agree? And you've seen this tension in the other plot that I've ah shown you, whereas in the inverted hockey they seem to, you know, overlap quite well.
Um.
And yet Nova, when is fitted by it on its own.
Um.
You know it. Ah.
It favours the normal ordering. Its best fit is in the normal ordering.
Um. So you know, people and a lot of experiments favor the normal ordering. So so there's a question of why, you know, we have this tension here between those 2 big experiments.
Uh, and there was in here, and yet everything seems to be pointing towards the fact that we have a normal ordering.
Um so.
Um, you know we've sort of entered into an era of joints nowadays.
Um. So normally, theorists do this kind of thing where they combine the data from um different experiments, and to get an average of whatever the parameters that they're looking at.
Um. But the experiments found that if they do it properly, they can really take into account all the correlations between different systematics. And, you know, nutrition, cross sections, flux systematics, and so on, that they already know about because they have got all the simulation in place to be able to do this. And so experiments have sort of started doing.
Joint analysis recently to try and degeneracies the fact that they have different baselines, different energies.
They started to sort of expect different. You see different things.
And you know, if you do this fit um. Taking all this to account, you can actually maybe try to resolve those differences between experiments, and you can also try to push the boundaries and get a more precise result.
Um.
So this is sort of where things have been heading recently, somewhat.
Uh. For example, Super K. And Tk. Have published an analysis.
Uh? Where?
You know super case.
Um at this limit.
Here, and then you have um.
The um superk plus Cdk is in red, whereas Ttk was in blue. So you can see in in this case there's a preference for normal ordering. Again, as I mentioned.
And um, and the Ttk being data, Dom.
You can really see it here. You know, the blue and the red are very similar.
But still, you know, there are experiments that are very related. Right? They use the same fire detector except super care users, atmospheric neutrinos.
To do those you know. Measurements of that time square 2 and theta 2, 3, whereas T. 2 K. Uses the beam.
So, you know, you can easily do a combined analysis.
A bit taller is is to do a combined analysis of the experiment, because.
You know, the halfway across the world from each other they use different um beams.
But um, you know.
This has been done, and.
Hey? And it has been shown that basically, if you look at in the normal ordering.
If this is some.
The.
Tk, result. And this is the Nova result.
The um. So this.
The Nova result, then.
The purple surrounded by the black is the actual combined limit. So it.
You know, people thought that he would get a very sort of precise result, and it would give us all the answers.
But it didn't. It actually told us that, you know, we're still consistent with maximal mixing.
And you know, we're still sort of consistent with that. Cp equals 0, and it just split things down the middle. Um, so it was very interesting, but it's still very interesting that we can do this now, and people are hoping to be doing this with more data also in the future.
Um. So, as I just said, we're entering a an email of high precision. And uh, you know, it will be very exciting over the next few years, because um.
You know, these are sort of different experiments. What they're projected to see.
Well, that sounds great, me, too. So this is what we now see. So you can see that the arrow here is very small on this parameter. But actually, you know, there will be experiments here.
And I'll focus on Dnn. Hyperkay that.
You know, would be able to do so much better than the current experiments.
Um.
So we are entering this about position in nutrition physics, despite all the difficulties in trying to do experiments with such a you know that with particles that's so badly interact.
Um, and so.
What we want to see.
With all the taxes.
Uh all of those types of things. So we wanna see neutrino neutrinos.
Astrophysical neutrinos, maybe from galactic nuclei.
Maybe uh. We also might be able to see course on decay. This is sort of not a neutrino, but we might be able to see that as well.
And so atmospheric neutrinos are also the bread and butter of those experiments. But you can see here from the slide sort of with all those things.
Is that we're really building multi messenger neutrino observatories, that they're capable of a lot of things. Not just the one thing which is.
To measure those you know, parameters that are from oscillations. We can measure many things.
And so that's what we want to.
So I'll tell you a little bit about.
Um those experiments. Um.
I hope I'm not running out of time.
So Jean um is will be this big giant detector. It will be a liquid Argon detector again. There'll be a beam.
That's being constructed that will send.
Uh, you know a neutrino family up um to some near detectives at firm it up, and then to a father. Um.
Far away, 1,300 kilometers, this time to increase the baseline, to maximize, the sensitivity, to Cp violation, and all those things.
Um. So so do you guys being currently built.
Um. And uh, you know, it's basically gonna use the next generation beam. That's even more powerful.
Um to detect, to produce those neutrinos.
Um. He was a protagon single phase. So this is a detector that was.
To try. And, you know, do some testing um.
To see how those instruments look like and like pedagogan, because the reason you want to use liquid.
Is that you get those ua beautiful.
Event displays that tell you all the details. What's happened in the neutrinal interaction. So this is an actual, real data for microburn, which is one of the smaller liquid in the Us.
So this is a 600 ton detector, and you is going to be 17 kilons.
So it's much, much bigger uh, but it's judicial volume. So the volume, when you do, the analysis is going to be 10 kilotons plus.
This was going to be times 4 at the beginning there was going to be 2.
Such detectives, and then they're going to add another to you later.
You know it will be absolutely massive. Imagine this times 4.
Um.
So.
Um! There was this underground facility that has been.
Uh is being excavated or has been excavated. And here you can see the 1st 2 detectors.
Uh, you know, and then there's space for another 2 detectives.
Later on, and this has all been.
Uh excavated liquid argon.
Um at 87, Kelvin.
It's very, very, very cold, you know, and so it's a it's quite an a big challenge to build such.
And suddenly, you know, deep underground is an even bigger challenge.
Uh, if you're trying to build such a giant detector that's never been built.
Um the whole. The prize is basically that you know, you get those. These are actually an event displays.
Uh in the test theme. So you can see.
Ah, this is a 6 Gb. Election candidate.
This is a 1 Gb proton candidate. So you can see so much detail. And this is really what Gn. Is going to be fantastic at, you know, detecting.
Um, you know, being able to just do this amazing analysis where those very detailed um event displays.
Um.
And so you know, as I said, it's very complex.
Um. It has taken many years by many scientists.
To come to this. Um, you know, there's different. That's going to be 2 different types of like, we're going to text that there's going to be an amazing.
Near the tech uh suite of detectors.
Um, you know some of it's going to be very detailed. Ah! Like a fine grain Collider, like Detector, which is going to be.
Been head on. And then there's going to be this liquid agonist going to be moveable on rail so that you can sort of scan your neutrina beam and get even more precision with your measurements.
Um.
So you know, this is currently all being made and produced.
And uh, you know the the bread and butter which is the oscillation. Um, you can see that, you know. They expect.
To see in 12 years, roughly, that many nitro neutrinos appearing, and that many neutrinos.
Appearing, and you can see that. Uh, you know. There was a.
Difference here. So, depending on the Delta Cp value.
In one case.
Um. You know the blue is below the black, and in the other case the blue is above the black.
So you can see that you can. It shifts places so that gives you this sensitivity to delta. When you have loads and loads of events.
So if you I don't know if you paid attention. But the number of events we have so far is in the tens, maybe 100 or so for the experiments we have.
And here you can see, you know, hundreds and hundreds of events.
That are going to be observed.
And so, yeah.
Uh, you know, in the best best case where you.
Ctc. Is the most favorable. They expect to be able to tell us. The mass ordering.
In one year above 3, sigma, so we'll know which neutrino is heaviest then, which one isn't.
And also um, they will know data. Cp, um, in within 3 and a half years.
Um. Obviously, if it's not best case, it takes a little bit longer, but it will still be able to be amazing uh, and to discover this.
Um.
There's other things that it will be able to.
Uh, for example, it will be able to.
Um see supernova neutrinos.
Uh, you know, it would be able to sort of figure out.
Um.
How it happens in time.
So, you know, depending on neutrino oscillations. You can see here.
No issue. Oscillations is blue of green, it's inverted ordering red. It's normal ordering.
You, you expect to see something different. If a supernova happens.
And so, do you know, would be able to do this? Did you realize that when a supernova happens, the neutrinos that arrive at the earth arrived earlier than the light that arrives.
Ideas, just because the live particles.
Bounce about on the way out from Supernova, and on the way here, as the neutrinos just go straight through.
So so actually, um, our detectors will be a warning system, for when already are actually physicists to go and astronomers to go and look for supernova.
Ah! Because we know about it before they know.
Um.
So now I've shifted. I'll tell you about Hyperc.
Um. So, Hi, Beck, it's a very dear to my heart to actually work on it a lot.
So this is the other um big detector that's being built.
Um, and uh, it's essentially uh the next step. Evolution of the detector is basically very similar to Super K, but just bigger and better. And uh, there are approximately 600 collaborators.
On this and.
It's judicial volume will be about 8 times bigger than Superk.
And it's basically equivalent to about 80 Olympic swimming pools.
Of water in one giant.
Uh. So it's about 70 meters tall and 70 meters uh wide.
And it will be filled with ultra pure water. And because it's in Japan, it's using the JP or will be using the Jacinta beam.
So. Um, you know, as I said, it's the successor to superk.
And it's a well understood technology. So this is one of those.
Super event display, so that already explained.
So you can see how pretty they look, and how you know you can really tell.
That this is a neonutrino, and then here you have.
You know these are sort of Pid. How you can tell about those rings. You can really.
Ah! Determine, you know, whether neutrino was election like Orion, like.
This is another nice picture of the detector. But um! What I want to emphasize is that it's going to have more Pmts.
Going to have 20,000 Pmts. Rather than 11,000. It's going to be bigger.
Um. So you know there are some numbers here that.
You know, it's going to have 260 kilotons, but the judicial volume is slightly smaller, because obviously you have a bigger volume for the detector, but then you have to veto things, and so on.
So you end up with a smaller volume. But this is basically 8 or so times bigger than the judicial volume of Super K.
Which is 50. Kiloton, with a smaller volume.
Um. So you know it's much, much bigger.
It's got 20,000 Pmts. Instead of 11,000, and those Pmts are also twice as sensitive quantum efficiency of finding those photons that we see when the neutrinos in track is actually double that of cip and better.
And you know we play leading roles in that experiment as well. By the way, as well. We we play leading roles on both during an.
So hypothetic progress. Um, you know, there's been some nice pictures shown. So you know, Pmt's are being delivered. So we're getting lots of food delivered in Japan.
Apparently 10,000 have already arrived, and they're being tested.
I think, in batches of 300.
In this dark room to see whether they're all okay.
Um here as well. We have built.
The 1st prototype target for this.
High power. 1, 2 megawatt beam, that hypercase going to be using.
Um.
And uh, you know, this is how the beam power is gonna go up.
As we get closer and closer right now we're somewhere around 800 kilowatt.
And it's expected to be around 1.3 megawatt.
At the moment when we turn on Hyperca.
So hypoc sensitivities.
Just and briefly, I'm running out of time. So you know, hyper care will be able to do similarly. Well, to.
To June. Um when it comes to, you know, measuring the Uh mass ordering, and also um, you know, it wants to measure the Octa.
2, 3, and Delta, cp, so all of those things will measure as well with hyperk. So again, you know, there is complementarity going on between. You know the Hyperkay and June. You know we need both.
We can't just have one, because if you only have one, if you find something unusual, you need to prove that it's actually true.
So.
You you know.
Hypoc also will have obviously sensitivity to.
Super nova neutrinos um. So, for example, we would expect 70,000 events. Um, if a supernova happened 10 kilo past 6 away from us.
So, you know, that's a huge number of events you suddenly get, you know, within a small amount of time of one or 2 or 3 seconds.
You know this is how short those bursts are, and you suddenly get swamped with so many events.
Uh. So you can do amazing physics with this if you get a supernova. So we're all hoping that some stars going to explode nearby.
As soon as we push on, the detectors.
Um. There's also things like the super defused supernova background, which is something that basically comes from relic neutrinos that were produced in the past in supernova, in the universe. Up until the present day.
And uh for hyper care. We expect about 4 events.
But yeah, there you can see that the energy is very small, but this is sort of the energy of the supernovae can go down to roughly 3 or so Mev. In energy.
So you know, the sensitivity is absolutely amazing.
And uh an interesting thing from Superk. Uh, just literally a few weeks ago. Um.
They have seen a hint.
2.3 Sigma hinterland supercure data of actually having.
Such a, you know, diffuse.
Um neutrino background.
Ah, neutrino! So you know you can see here, red is.
You know what they sort of expected to see if there if they are there. And this is the data, and they sell something. It's just. I think it's about just one event. But it's interesting, you know, that we're sort of.
Starting to do the solar astronomy kind of thing.
Um, you know in.
Um.
So hypocrite, timeline, so.
The dome has been excavated for the for the detector and.
This is absolutely huge. I believe that at the moment when it was excavated it was already the biggest ever um single excavated chamber human made chamber underground.
Uh now the digging down so you can see the digging down.
You know, with those you see those excavators here, you know, on this picture, you really, you know, can't imagine the scale of this.
And obviously um.
This is expected to finish sometime October, maybe a little November. So by the end of this year.
And uh, you know, we hope to build a detective.
Afterwards, and then start operation sometime in 2027 and start digging data.
And when we start taking data, one thing is important, um, hyper care will be able to start taking data already with beam. So with Gene. Unfortunately, there's going to be a slight delay.
Of a couple of years before the beam is ready. After the detectives are ready.
But you know, as I mentioned, you can measure other things neutrinos, and so on. So both experiments are really interesting, and we'll be delivering data within.
You know, before 2020, before 2030, I believe.
Ah! One other little thing I wanted to just.
Mentioned here is that you know I said, dark matter with neutrinos.
So both Gen. And Hypercage should probably be able to detect.
Um, and actually some neutrinos from dark matter.
Um. So you know you have.
Whims that are so metaphroduct metal they can.
Um. You know they can decay and annihilate and produce.
Um Doc Meta a standard model particles, apologies.
And so they produce a neutrinos, and so.
What happens is that you can do indirect matter searches so you can look towards the Galactic Center.
And you can search for an axis of neutrinos coming from that.
Uh place uh you can also look for uh so-called.
Um Kay Douges. Key indicators. Um.
Uh neutrinos, so they will decay. Pions will decay, and.
Chaos will decay on the edges of the sun.
Um, but because the dk at rest the neutrinos produce will be at one discrete energy.
And so you know the for the finance. It's.
It's about 30, and maybe, and for the chaos it's about.
236, and maybe but if you see such a peak of you know discrete energy neutrinos in your detectors.
Then this is probably a signal of that matter.
Um using neutrinos. So this is also something that we'll be looking.
To do.
So now I just sort of.
Tell you all the things I haven't discussed here.
How many? Uh, you know, this field has developed so much since I've started.
Um.
You know, a while ago. Uh, you know, it's just become bigger and bigger and bigger. There are many more experiments in the way when I started when I started. There were, you know, you could probably count the experiments on maybe 1015 experiments. You know. You could keep track of them now it's almost impossible. There's so many.
It's with so many different equidents. It's absolutely terrifying. But that's because the field is so vibrant. There are so many things that people can discover. And you know we've discovered, you know, that those 7 intrins.
I'll try her energy. I haven't even discussed.
I haven't discussed the tunnels that were bit.
Uh, you know Nutrina's the absolute nuts.
Beyond the standard model physics that people are looking for. Even Lhc is now looking for neutrinos.
Um, you know, which is a completely separate thing, but they're also trying to find them in New Texas. Um.
You know all those things that we're trying to measure one plot I absolutely had to include. What's this.
Plot from this ice cream collaboration. If you don't know about the ice cube experiment, it's based in Antarctica and.
It's basically a giant neutrino telescope.
Build into the eyes of Antarctica, and if you haven't read about it, I would really encourage you to go and read about it. But what they've done recently. So they published this in 2023.
It's absolutely amazing. So they've taken.
The center of our galaxy and.
You know, shown how it looks in the optical spectrum. Gamma, ray spectrum um.
You know, and then they have shown it how it actually looks.
In the Neutrina, observed spectrum.
So this is what they get. If they, if they look in the direction of the galaxy.
And this is what I see in neutrinos.
Really, really.
Interesting. I think.
So anyway, um.
I think I don't know if my.
Um. You know, if if those.
You know, points out what's making, but I think it's just.
Very exciting. Um, you know, we're continuing to take data with existing experiments, that which are gonna have.
Double the data and even triple the data, you know in terms of no one. Tk, um.
By 2027. We also have.
Tune in hyper care being built. We also have other experiments being built.
And running as well, that are also making new discoveries. And you know that's so many experiments.
Um. But I think we're entering into this position as neutrino.
Measurements and astronomy, that I think nobody really expected to be so vibrant by that time. So.
I think.
That's my main conclusion. Thank you.
Thank you very much, Anna. I guess we have some time for some quick questions. Does anyone have any questions in the room?
Not everyone at once. Um, if there are no questions, then oh, we have got a question. Fantastic.
Um! This is fairly on your slides. But the graph you showed about the.
Oscillation probabilities between electron.
New one who knows.
Do those probabilities? It high energy on the X-axis? Do they converge uh.
A 3rd each. They seemed like the.
You and entire decreasing. And the electron was increasing.
Is that the person? No, I. If you zoom out it goes, then down again.
And so there are actually plots where you have CC zoomed out, and it goes down.
Hmm.
Are there any other questions?
I thought that might get the ball rolling. Ah, yes, fantastic.
Thank you. I was wondering about.
The map of um astronomy with neutrinos.
It looks like there are some dark spots. There is any idea if these are rare so, but they could be.
This is kind of the new sources in the garage.
Oh, I don't. I think you know this is uh.
I don't know. Maybe I don't know. There is. There are neutrinos that we expect to see, for example, from blazers, for example, which are very active. Galactic nuclei point.
Um straight at us.
You know we have the jet emanating comment, pointing straight at us. So it's.
You know, at the moment I think it's a it's a speculation, probably more than anything I would probably have. You would have to ask. Maybe astronomers as well as uh other theorists.
Um. It's it's as I said, it's so new, right? Everybody is just super excited about it, and.
So so the sky's the limit.
Think.
Are there any other questions?
Um. So you you detail some of the sort of future experiments that you might see on neutrinos. What do you think.
We might see.
Looking to the far future. Do you think people will continue to build bigger and bigger detectors? Do you think.
Looking more into.
I don't know more.
Precise.
I don't know for angles for astronomy or or something. What do you think.
So I think in the near future.
Uh the whole.
A lot of the game is about reducing errors. For example, you know, nutrient cross section errors, you know, all the experiments are sort of around 5, 6% right now on the total systematic error in terms of oscillations.
And people want to push it way down. So you need to get better errors on the beam flux. Better errors on the cross section. So a lot of this is being done with those detectors to really precisely measuring and measure all of those things.
Um.
In the far future. There's an interesting question. Um! There was this very interesting talk. I saw a couple a few weeks ago, and it was my typori from a King's College, London.
And he had this really interesting plot of LE.
Which is basically the baseline versus the neutrina. And so if you zoom out, you can see there are vast spaces that are unexplored by any of the experiments.
Uh in terms of energy, and how far those neutrinos have travelled, and I think this will be something that people will be in a very far future trying to hone in on those very low energy tunes. Maybe, for example, for example, the dark matter experiments. It turns out that some of them are able to, you know. See those you know recalls from the very low energy neutrinos, and so they might be competition to the standard neutrino experiments, and so.
Of the areas.
In the future, because they'll be able to see those.
When we can't, with those experiments that we have.
Um. But you know also higher energies. You know, it's it's just.
Is this a huge giant span of energies and distances that we'd have to explore.
Any other questions.
If not, then uh, can we thank our speaker once again?
Yeah.
Nothing.
Um, thank you very much. Thank you for coming, and I think there's 1 again next week, same time.