James Smallcombe: And then I'll handle Caitlin and say, please take it away and tell us about this work.
Kaitlin J. Cook: Thanks for the invitation and thanks for the nice introduction.
Kaitlin J. Cook: I'm yes I'm here today to talk about
Kaitlin J. Cook: work I did as a jazz Paris fellow
Kaitlin J. Cook: Turkey Institute of Technology, and I've met that stage of my career where I'm you know repetitively changing my affiliation.
Kaitlin J. Cook: So I'm currently an effort and the Department of physics, astronomy, as a co appointment. So that's why it's so complicated. Um, so yeah, so my work is in
Kaitlin J. Cook: Predominantly has been an infusion today. When I was a PhD student. It was fusion based is it's fusion. This work was anomaly. For me, I got to do structure and fast beans for a year. So it's fun to do as a postdoc, and I'm a dealer talk at this, but I'm still very glad to present this work.
Kaitlin J. Cook: So because I'm lazy and I don't want to put a reference and every slide. This is the reference of the work. The letter was published a couple of weeks ago. It wasn't even accepted.
Kaitlin J. Cook: When I decided when I was offered to do this talk. But if you're interested in meeting more you can find it here.
Kaitlin J. Cook: So, I mean, just in the born 19. I mean, just in nuclear halos and neutron halos in general. So I'm going to sort of focus on on the neutron side of stability in this talk.
Kaitlin J. Cook: So neutron halos things that appear sort of around the nutrient reply. So this is orange curve here I've pulled it up to oxygen. So sort of talking about like very, very nutrient rich nuclei.
Kaitlin J. Cook: Into a circle. Every hailer that we even know exists or we think that it's it's quite a number of them compared to the number of new clothes. It's almost like common
Kaitlin J. Cook: We can have sort of one neutron halos things like really 11 or two nutrient halos things like lithium 11 somewhere. The basic idea is that the
Kaitlin J. Cook: tail of the neutron density extends far outside the core. The central core of the nucleus. So as a consequence, you'd expect that you have a large interaction radius for lithium 11 that they expect from this what you'd expect from the radius. If you calculate the radio at stability.
Kaitlin J. Cook: So born 19 what I'm going to talk about today is sitting right here. So it's right out if there's a it's an interesting jump between
Kaitlin J. Cook: Brilliant, brilliant and born with five extra neutral neutrons being added to get to the drip line here.
Kaitlin J. Cook: I'm all for it to each other to burn 19 six out here, it's a long way out. It's What's kind of cool about it is it's bromine, bromine means that
Kaitlin J. Cook: It's a free body system where neither of the two body subsystems of bound so boring 18 so for and 17,000 each one is unbound and the tutoring system is of course I'm bound in a vacuum.
Kaitlin J. Cook: And that's fine as also what we say in helium six as a sort of and lithium 11
Kaitlin J. Cook: But born 14 parents 19 rather it's also built upon Brian 17 which is itself Burmese is a sort of nesting doll of these kind of interesting structures. So it's a nice Nicholas to study.
Kaitlin J. Cook: But in general, what would also like to know is how
Kaitlin J. Cook: Halo structures evolve with increasing this at places like making our BF and effort when it comes online and fair in Germany.
Kaitlin J. Cook: What we're going to be doing is mapping out further and further and further
Kaitlin J. Cook: Hiring mess the niche hundred fine. So it's kind of, I think, an interesting and important question to ask is how do these Halo structures or any just neutral skins evolve as we get heavier. So it's kind of worthwhile. I think
Kaitlin J. Cook: Just from that perspective to try and understand Halo structures with increasing this
Kaitlin J. Cook: So I'm born 19 is an interesting nucleus, like I have. I've kind of convinced me it's weekly bound something like 90 k plus or minus a half and MTV.
Kaitlin J. Cook: Threshold to remove to neutrons. So it's very quickly band, but uncertain and it's also relatively it couldn't afford each removal
Kaitlin J. Cook: And it has a large reaction cross section. So something like 1.2 bands at 740 and maybe even up on. So up until now. This is for the two pieces of information that we had experimentally about born 19 typically what you'd expect is
Kaitlin J. Cook: That these are sort of candidates for Halo right you have reached binding and you have a large reaction cross section, which suggests that the nucleus is large.
Kaitlin J. Cook: That isn't sufficient in itself to have a have a halo. So go back here, we require for Haley to appear that we have weak binding of violence which wanted to have a born 19 but we also require that those neutrons have low orbital angular momentum. So it's typically si P waves 01
Kaitlin J. Cook: There has to be so that has to be decoupled some half of the internal call if the angular momentum is too high, then the new trends are confined basically by that centrifugal barrier.
Kaitlin J. Cook: So,
Kaitlin J. Cook: We need to know something about the valence electron configuration and born 19
Kaitlin J. Cook: So previously, when we just type in the bits of born 19 that we end up with the we knew we had the reaction cross section and then you turn separation energy
Kaitlin J. Cook: And put that together with some simple models suggested that maybe born 19 doesn't have too much of a halo effect that should be mostly the wife.
Kaitlin J. Cook: So that was sort of maybe doubting the idea that born had a halo
Kaitlin J. Cook: Um, but, so we're looking. And one of the reasons it's worth actually looking at besides knowing for sure is that born in 18 so that one of the subsystems of born 19
Kaitlin J. Cook: Shows the largest known scattering length of any nuclear system so largest isn't most negative. So my it's at least minus 50 family.
Kaitlin J. Cook: Affected meters, depending what you like to say. So this is a interesting candidate for what's called efimov state. So an economic status something. It's really famous in atomic physics.
Kaitlin J. Cook: Where the scattering length of the two bodies of a to buddy subsystem of a third party system approaches negative infinity scattering life.
Kaitlin J. Cook: So this is something that hasn't been identified in a new place, but it's something that people are definitely interested in finding
Kaitlin J. Cook: So, okay, we need to know something about the hell of born 19 now very good way of doing it is by looking at the saw the one transition strength.
Kaitlin J. Cook: So if you take a standard nucleus so well band nucleus, it doesn't show anything exciting with a halo or you measure the one strength and functional excitation energy
Kaitlin J. Cook: You see that basically all of the one strength is concentrated up with 10 or 20 and TV in what's called the giant dipole residents sitting up sitting up here somewhere.
Kaitlin J. Cook: But for Halo nucleus, what we see is a large amount of transition strength that very low expectations around 1am EV, and this is what we call the soft one transition
Kaitlin J. Cook: And what's very nice about it is it's uniquely and also universally seen in highlights and it's a product, it's as it appears as a consequence of that extended nuclear matter distribution.
Kaitlin J. Cook: So to show you the experimental data services lithium 11 and brilliant 11 we see a peek and the one strength for the function of relative energy around one Nev
Kaitlin J. Cook: And when they integrate we get something like one is quite funny squared up to about for me.
Kaitlin J. Cook: For not have a nucleus would expect him to the minus three, four transition strength. This is a really, really, really substantial increase
Kaitlin J. Cook: And what's really good about it is it doesn't only tell you that you have a highlight it tells you something about the halo. So the size and shape of the distribution is sensitive to things like the size of the highlights of that core neutron distance
Kaitlin J. Cook: The balance between configuration and for modern furniture and halos. We also are sensitive to things like dynamic from correlation. So whether or not our nuclei, especially correlated
Kaitlin J. Cook: And also the final state interaction. So the interpretation of this distribution is fairly simple. For one, you turn halos.
Kaitlin J. Cook: incredibly complicated for Tunisia inhalers, because we have those final state interactions and those features and configurations to take care of.
Kaitlin J. Cook: So the interpretation of this tends to be more independent in a way that isn't for one each and halos. But nevertheless,
Kaitlin J. Cook: Within a perfect model, we can tell a lot about what's going on with the halo by measuring the software one. So that's what I'm gonna try and do. And the way we can do that is by measuring McCullum break up with a colon dissociation cross section.
Kaitlin J. Cook: So I'm going to do that at relativistic energy. So if we have a born 19 coming in up energies faster than 30% of speed of light, at least. So in this experiment. It was about 60% and we're going to impinge up or 19 on a hybrid target. This is always like, that's an easy target.
Kaitlin J. Cook: And when they interact. We want to have a cooling process. So we want the nuclei to interact with the cornfield other medical field.
Kaitlin J. Cook: And when they interact. They're going to exchange virtual photons, hopefully, and it's pretty easy to excite born 19 and born 19 is going to break up into born 17 plus to any thoughts.
Kaitlin J. Cook: What we want to do is we want to measure all of these a mentor in coincidence. We measure the new trends in coincidence of foreign 17 we make sure that the mentor can measure them and mentor, we can extract the invariant mess. And from that, the relative entry distribution.
Kaitlin J. Cook: So that's the game and then we want to go from a column Association code section to our event transition strength and I'm going to do that using what's called the equivalent photon method. And this is why we did it at
Kaitlin J. Cook: The relativistic energies, because we can apply semi classical formulas like this. So basically we can sit, we say that we can wrap the coolant Association cross section as the product of a virtual photon spectrum and that he went transition strength. So basically we affect racing out
Kaitlin J. Cook: Structure part being that he won a big one. And then our phone number, which is a reaction part
Kaitlin J. Cook: And we can calculate this using the equivalent for non method. And if you look at the photon spectrum or for calculate the fight on spectrum for that tuned and 20 Navy nuclear just what we measured, we get a photon spectrum that looks like this.
Kaitlin J. Cook: So you can see that was sort of have an increased sensitivity to be a lot more virtual photons down here precisely would like to look so it's a nice convenient feature here.
Kaitlin J. Cook: So we did this experiment at we can at the grips. So this is a plan, it's a bigger sits here and we do that experiment at summary. So for looking plan view.
Kaitlin J. Cook: It looks something like this. So here is our to cycle John's so the superconducting second one which actually is the first superconductor inside your time any like that recently.
Kaitlin J. Cook: And its massive and it's going to provide us a beam of 200 products and no amount of calcium 48 345 any be clinically on and we smash that on a stinking great big thick brilliant target setting millimeters thick as a fusion person. All of these numbers see massive to me.
Kaitlin J. Cook: And that when of course, we have a high nature casting for yet been hitting a brilliant target, what we get is fragmentation reactions.
Kaitlin J. Cook: So we get a whole slew of things that come up and we want to purify and identify are being so we do that with big groups so big groups is a two stage.
Kaitlin J. Cook: spectrometer. So we have a purification step that measures, we first measure that or separate rather
Kaitlin J. Cook: Based on the rigidity, we do it. And if we take we do an energy last step with a wedge and then we separate again and rigidity.
Kaitlin J. Cook: After we separate them. We want to identify a cocktail being that's left. So we measure the time of flight.
Kaitlin J. Cook: We mentioned the rigidity. We mentioned the energy loss with those three qualities we can determine the charge. And we can also mentioned the message of charge, and that should uniquely identify a beam.
Kaitlin J. Cook: So after our purification and identification stage we had 120 particles per second.
Kaitlin J. Cook: Or 19th at 10 and 20 Nev clinically on that was delivered as a cocktail been to summer. So here's what our cocktail look like
Kaitlin J. Cook: At here is born 19 it's nice because it's so well separated from virtually everything else.
Kaitlin J. Cook: But we also had quite a large amount of Brian 17 as well as carbon 20 in this experiment. These are contaminants
Kaitlin J. Cook: They're interesting nuclei in and of themselves. And this is the kind of experiment where everything was measured and everything is going to be an analyzed. Eventually, I think, but this is this is where I'm looking
Kaitlin J. Cook: So being this live in December. Now summer I is a spectrometer based around this large superconducting tackle magnet now its massive on this person sending their sort of the scale.
Kaitlin J. Cook: But what's nice about it is that this has a huge gap that makes it very efficient for measuring fragments. So being is delivered through these
Kaitlin J. Cook: Last quarter pole and through a bunch more detectives to characterize the trajectory of the beam or impingement on a leg target also in a carbon target.
Kaitlin J. Cook: So I thought it was surrounded by the dalai tour, right, which is arrive sodium iodide for measuring gamma rays. I'm not really going to go into the gamma rays here because we didn't see any in coincidence, with the ball and 17
Kaitlin J. Cook: Which tends to just suggest that we're at least 95% of the time populating bro and 17 and its ground state.
Kaitlin J. Cook: So then after being excited in the target are born 19 comes up and quickly the case into born 17 plus two neutrons. Now, what we do is we mentioned the trajectory of the barn 17
Kaitlin J. Cook: Through summary. So we measure the position before the position after and it gives us the magnetic rigidity and we identify it with a horoscope
Kaitlin J. Cook: So this gives us a momentum of the barn 17. Now the reason for passing it through a magnetism. Now that sweeps that away from other on charged particles.
Kaitlin J. Cook: Being to neutrons. And now we mentioned to Nick Johnson coincidence.
Kaitlin J. Cook: So identification spectrum here for the born 19 looks like this. So this is gated on born 19 so if we put born 19 in of course we're mostly get is born 19 on the way out.
Kaitlin J. Cook: So we could also get a reaction cross section here and that's part of the PhD work at SUNY setter at to Tokyo tech. So I guess we should look for type of that in the next couple years.
Kaitlin J. Cook: But we also mentioned the porn 17 and the bar and 15 and a few other it really nice to type of sitting down here, something
Kaitlin J. Cook: So the difficult thing in this experiment is that we're measuring nutrients in coincidence.
Kaitlin J. Cook: Now when you want to make sure to signals in nebula. So we measured on each one's a nebula. It's a large plastic simulator array, sort of, you know, 1.8 meters by 12 centimeter bus, but it's pretty massive
Kaitlin J. Cook: What we mostly get is false coincidences or or crosstalk because you don't come in, it will scatter
Kaitlin J. Cook: Sphere, you know, scatter and give you another signal which can lock an awful lot like to neutrons. So the big and the difficult part about
Kaitlin J. Cook: Multi neutron coincidences is dealing with us. CROSS TALK rejection. Now we can talk about that in the question time if anyone has a question about that. So I don't want to go into its own integrate the results.
Kaitlin J. Cook: But this is this is where the effort is and we also determine the efficiency using john for simulations that sort of taken recap all of this.
Kaitlin J. Cook: So after doing all of that work. These are the results. So this is the cross section.
Kaitlin J. Cook: For as a function of relative energy for the reaction on the lead target and they're actually on the carbon target. Now the coven targets actually been
Kaitlin J. Cook: After doubled in the spectrum. So it's above the y axis, you can see it's really, really tiny and the lead reaction. It's very much larger peaking sort of below one Nev
Kaitlin J. Cook: Quantitatively speaking the lead reactions on lead to have a cross section or something like 1.1 bonds was the carbon at 60 million bands.
Kaitlin J. Cook: So you'd, of course, expect that reactions and lead to be larger than reactions and carbon on a geometric argument, right, that is a big nucleus and carbon and gives us a bigger size to the colliding neutrons and you click on
Kaitlin J. Cook: Something, um, but for not have a nucleus and going from geometric geometry, you'd expect that to be about a factor of two.
Kaitlin J. Cook: But instead, what we see is a factor of 22. This is really a very, very large enhancement over what would expect from a non health nucleus, moreover, all of that cross section enhancement is sort of below when MTV, or the vast majority of the enhancement is blue one MTV.
Kaitlin J. Cook: So this by itself is a central result we have a clear indication of an enhanced Columba Association cross section.
Kaitlin J. Cook: Which is telling us that born 19 has a halo. So everything after this is basically interpretation, but this is the key and central experimental result. It's fairly unequivocal. The born 19 has a substantial hailer
Kaitlin J. Cook: Um, but before we go much further and go into getting a one strengths, we have to we should ask the question of whether or not we have a to nutrient Halen or furniture handler going on.
Kaitlin J. Cook: Because I mentioned Berlin 17 in coincidence of to neutrons and basically probing this part of the way function where we have borne 17 and two neutrons predominantly anyway.
Kaitlin J. Cook: Now, we didn't measure for nutrition coincidence. In this experiment, the quarter the efficiency in nebula for for neutrons is tiny. So to give you an idea for a single neutral zone.
Kaitlin J. Cook: Detection deficiency of nebulous something like 35% for to neutrons, it goes down to 7% so then you can imagine for full neutrons. It's incredibly tiny and again we have the cross talk from which which doesn't help.
Kaitlin J. Cook: But what we could do is we can measure the inclusive cross sections. So that's where I'm sure for 19 going in Berlin 17 are born 15 coming up and not requiring any kind of coincidences with a neutron
Kaitlin J. Cook: So when we look at these. So these are the inclusive cross sections for to nutrition removal and for for nutrient removal
Kaitlin J. Cook: And the to neutral. Neutral case we have an enhancement about a factor of seven for later. The carbon. This isn't quite as much as for the input exclusive case because we've got much more nuclear processes going on that can be happening.
Kaitlin J. Cook: But for the furniture in case it's something like a factor of three. And this is pretty close to affect your sort of two to four expected from a pure and nuclear process.
Kaitlin J. Cook: So from this week include two things. The first is that our exclusive measurement for tonight trans is going to give us a good measure of the total column dissociation cross section and as the total one strength.
Kaitlin J. Cook: Which is quite an important consideration. And the second is that probably there's not a lot of the way function of born 19 that's being born 15 plus four neutrons.
Kaitlin J. Cook: Okay, so we've got some confidence that what we're measuring is actually a complete giving us going to give us a complete measure of the coolant Association cross section.
Kaitlin J. Cook: The next job is trying to try and get that column Association cross section what we measure is the breakup on lead right so we measure some kind of some of the cooler than the nuclear processes.
Kaitlin J. Cook: To what we were done is try and quantify how much of that is cool and how much of its nuclear there's basically two ways to do this. The first is by cutting on the angle and we don't have the angular resolution to do that. So we have to do the other way and the other way is to assume
Kaitlin J. Cook: That the relative distribution of the nuclear component in lead looks the same as the nuclear component in carbon up to some constant faction.
Kaitlin J. Cook: And that constant factor is what we're going to call gamma i mean this is why we make sure the carbon, the carbon allows us to characterize then you click component of the breakout
Kaitlin J. Cook: So you can see the expression here. So the challenge is to say how much how big, how much bigger is the nuclear component of life, compared to the nuclear component on carbon.
Kaitlin J. Cook: I sort of started talking about that a little bit earlier. Basically you assume that the nuclear component scale to the radius.
Kaitlin J. Cook: Historically. What we do then is we say, okay, the nuclear reduces our terms to the one third.
Kaitlin J. Cook: As we've always done and then we write gamma. So depending on who you talk to get my, then it should be either the ratio of the some of the ready. I have the lead and the projector.
Kaitlin J. Cook: Or the ratio of the just the ratio of that to the carbon something like something like 1.7 so born 19 if you use this expression.
Kaitlin J. Cook: So this has been done by quite a number of people. But then in 2015 you cheetah and colleagues as the reference 2014 Marla
Kaitlin J. Cook: Demonstrated that this doesn't work for halos. And maybe this isn't surprising because the entire point of the halo is that it hasn't been enhanced interaction areas.
Kaitlin J. Cook: So what is she doing colleagues did is they did everybody CDC calculations.
Kaitlin J. Cook: To calculate gamma. So the
Kaitlin J. Cook: Nuclear the nuclear component that's enhanced for for lead over carbon and that sort of basically satisfies
Kaitlin J. Cook: This equation.
Kaitlin J. Cook: And pulled out a selection of insurance depression energy for a whole host of one year term halos and the red bands here of what you get for this geometric assumption.
Kaitlin J. Cook: With our times to the one third. So you can see that gamma is basically enhanced at low separation energies or particularly low separation energies far beyond what you'd expect from the system medics and if our mind you born 19 instead of sitting, sitting around here.
Kaitlin J. Cook: So this would suggest that this sort of simple expectation really isn't quite valid.
Kaitlin J. Cook: So it is I've got a son at a second University music site for Muslim. It's his code issue being born 17 plus two neutron so die neutron correlation
Kaitlin J. Cook: Because it's the by the CDC. This is all we could do and using that we've got a gamma that various of suppression energy but at half in a movie, which is sort of just at the upper end of that.
Kaitlin J. Cook: Measured each and separation energy. We got 2.8 plus or minus 1.6 plus or minus is coming from our basically our uncertainty that separation energy
Kaitlin J. Cook: So this is obviously model dependent. But what's nice is this doesn't matter. It doesn't matter because our cross section for carbon is much, much less than the cost section.
Kaitlin J. Cook: For lead you know factor 22 so whether or not we choose to point out, or three, or one or one and a half. It doesn't really change our experiment final colonization concession.
Kaitlin J. Cook: But it is something to watch out for. So this is a this is a big results. This is a conversation cross section extracted using this method using a gamma from CBC
Kaitlin J. Cook: So this doesn't look very different from the reactions on lead and that's unsurprising we still see this really enhanced cross section at low relative energies. This is a softy well
Kaitlin J. Cook: What we want to do then is going to compare it some little calculations to try and say something about the structure of the headline.
Kaitlin J. Cook: So in this what we use for the body calculations by again isn't
Kaitlin J. Cook: So his model includes it's a contact pairing interaction. So includes the bar and 17 neutron and then each connection file so introductions, which is really important. We use the word sex and potential to give us boring 17 plus neutron
Kaitlin J. Cook: Potentials so we very the depth parameter to give us two different scattering lights and the first being the upper limit of the scattering life from spiro and colleagues this paper here.
Kaitlin J. Cook: And my son hundred 20 which is sort of their favorite scattering like from that data. We also very dispute spin orbit potential to give us a d five houses, and it's inborn 18
Kaitlin J. Cook: Where it's predicted to be from model calculations and it's also seen an experiment. And then we also we very neutral. Neutral interaction to give us a different suppression energies to start off with 90 kV is asset value from the mass measurements.
Kaitlin J. Cook: So again, a science model gives us be the one to transform that the colon dissociation via the group photo method and we fold it with our experiment or solution.
Kaitlin J. Cook: When we do that we get this, and it's not great. It's not amazing right
Kaitlin J. Cook: We have changed to a log scale here. So it's extremely know amazing
Kaitlin J. Cook: But that's okay because our single the transit Tunisians oppression energy rather is quite unsettling so free very within our experimental uncertainty, we have something, it looks like this. So it going down from 90 kV up to 600 kV
Kaitlin J. Cook: We see that we should definitely span our experiment, just a rather large sensitivity to that. The one that looks the best is talking to maybe it does a pretty good job. We very much encompass the peak here, so I should say the dashed line here is a
Kaitlin J. Cook: Minus 100 centimeter square scattering nights and the solid line is that minus 50 family. So it's getting late.
Kaitlin J. Cook: So we're doing a pretty good job around the peak, which is where our software. One is, we're not doing so well over here.
Kaitlin J. Cook: It's sort of interesting because this excess has been seen in as far as I can tell, all in various mass measurements of halos.
Kaitlin J. Cook: Maybe this one's worth it almost all in this, but it's an enhancement right as has generally been put down to nuclear contributions and it's definitely a motivation for sophisticated model calculations.
Kaitlin J. Cook: But what we can do then is we can transform to be the one. So this is our baby one distribution as a function of relative energy
Kaitlin J. Cook: This is the same data would just transformed using the method. So the dashed lines of the same calculation just sort of pass a different way. And we can see here, actually, that we have some sensitivity to our SOS getting life.
Kaitlin J. Cook: Which is nice. I think considering this is something we would rather like would like to know about.
Kaitlin J. Cook: And then we see this enhancement. This is sort of small similar to what you might have seen in the previous paper. You see, to sort of this model that has been the one strength.
Kaitlin J. Cook: Now I should say that this calculation or this transformation has to assume some separation energy just walk them through the steps because I couldn't put on method is cost an exhibition energy Robin energy
Kaitlin J. Cook: So if you had a different as to when you'd mildly change it. One strength but with this as to when
Kaitlin J. Cook: An integrated up to six me TV. We have an event transition strength of 1.6 a square foot squared. If I remind you that are non halal nucleus, you'd expect something like 10 to the minus three. This is firmly in Halo territory.
Kaitlin J. Cook: The first thing we want to do is give information about how, what sort of size of the nucleus. This is so if we scare for model calculations.
Kaitlin J. Cook: basically taking the ratio between the model and the experiment, we get a core. So the distance between the core
Kaitlin J. Cook: And the center of mass of the two neutrons to be something like 5.7 Fermi or factors. So it's pretty large comparing it to him 11 sort of thing 11
Kaitlin J. Cook: Range is similar between five and 630 so obviously there's been a lot more mental calculations in the literature for the theme 11 than born 19
Kaitlin J. Cook: But it's definitely in the same sort of ballpark. If we compare that he one strength. So looking at 11. Has anyone strength 1.4 and brilliant 11 one one.
Kaitlin J. Cook: So this is certainly in that same ballpark of substantial well developed and it clear halos. So it's a fairly classic Helena Glazer, just might not have been exactly what we expected before doing this work.
Kaitlin J. Cook: So the next thing we can ask is what's the balance between configuration.
Kaitlin J. Cook: So again, we get back to a model calculation. So our model calculation that does the best job. So how many days, getting the minus 5050 meters.
Kaitlin J. Cook: We have an S wave occupation of 35% 35 house we get 55 56% so substantial as
Kaitlin J. Cook: Much as country the previous experiment else previous sort of interpretations suggested it should be almost entirely D wave
Kaitlin J. Cook: If we add all of the negative parody of overdose. Together we have 6% rounding out occupation probabilities. This is really dominated by FP show
On me
Kaitlin J. Cook: So that 35% is pretty comfortable to lithium 11 so if you look in the literature, again, a lot more models on the table for lithium 11 some variations between like 2341 and maybe up to more than 50% in a paper that have failed to site firm has a cell.
Kaitlin J. Cook: So it's pretty comfortable and maybe on the lower end of the expectations and within 111
Kaitlin J. Cook: However, the big, the big sort of caveat here is that our mental calculations assume that we have an inert born 17 core
Kaitlin J. Cook: But born 17 sort of double burn me and weekly bound structure. So, born 17 is a probable Halo with some sort of S wave configuration of it's balanced each one. So some of that. So I've probably has to go into the barn 17 or into the core
Kaitlin J. Cook: So this is why I'm not proposing a best fit here in terms of separation energy because if we were to have a slightly larger separation energy would have a slightly larger S5 component that could be going in.
Kaitlin J. Cook: To the barn 17. Cool. So this is a sort of complicated sort of multi dimensional sort of multi dimensional sort of calculation here that's going to give us this model. This one, the line.
Kaitlin J. Cook: So that we're not setting any kind of suppression energy here. This is what we didn't try and do that but
Kaitlin J. Cook: Saying that we can't have all of the slave going into the core, because otherwise you wouldn't see this Halo. There has to be some kind of substantial as a component in the born 19 and if you can pet. This is a model taxation sharing green
Kaitlin J. Cook: Where we artificially removed the S wave from the ground state. So there's no to one half configuration in the ground Satan's calculation, which basically completely exclude the possibility
Kaitlin J. Cook: Of a call a sort of a halo rather and you can see that, basically, we're doing a terrible job at the software one, which is what you'd expect.
Kaitlin J. Cook: So we have some substantial so of component Brian it because we have a call. It was hard, because we have a halo
Kaitlin J. Cook: So this is consistent with the born 18 studies which showed, we had a large is way better state as well as a small minus foreign conceptions rich say that we should probably have something like boring 17 cool
Kaitlin J. Cook: So the last thing that I want to pull out of our
Kaitlin J. Cook: Experiment results so experimental and theory results is something like something that the dynamic strong correlation. So the dynamic trend correlation is something that's been sort of long so after
Kaitlin J. Cook: In sort of these Halo multiplayer inhalers and the idea is that even though we can't have a bound pair of neutrons in a vacuum. We could have vampirism neutrons in the surface of nuclear meta that could be the surface of a of a halo nucleus.
Kaitlin J. Cook: Mutual skin or neutron star.
Kaitlin J. Cook: So that sort of the pure idea. These days, I think we sort of talk more about dynamic transits correlated neutrons in the court. So what I want to do is we want to look at the density distribution here. This is identity distribution model calculation that does the best job.
Kaitlin J. Cook: Of between the opening angle of the nutrients and the separation of the neutrons from the coins, assuming the neutrons had the sort of saying radius.
Kaitlin J. Cook: What we see in our density distribution for my calculation is that we have a large asymmetry in order to distribution. And so there's sort of three peaked distribution.
Kaitlin J. Cook: As mostly coming from the deep house and we have this cemetery, with most of the probability centered here on 25 degrees. So this is what we call these days, the donation correlation. So the, the neutrons prefer to be somewhat close together.
Kaitlin J. Cook: Now, what I find amazing what I found someone who's new to this really, really cool is that all of this I symmetry is actually due
Kaitlin J. Cook: To the parent interaction mixing a single particle levels with opposite party. So like I said before, we have 6% occupation and they have negative polarity states, mostly in the picture.
Kaitlin J. Cook: So even though that 6% an occupation is incredibly small. It's entirely causing this dynamic strong correlation
Kaitlin J. Cook: If we had a pure being. The wife would say three peaks here with equal heights. If we had s&d only would equal hot pics at like 165
Kaitlin J. Cook: And 25 degrees and sort of nothing. Not much many degrees as soon as we add in the FP other native parody states, this becomes quite prominent
Kaitlin J. Cook: So when you look in the literature and sort of inch in the introduction of all these papers. As always, as all you know we have to have S5 in the halo, but this is a real lesson I think especially, it was listened to me not not being used to anybody else.
Kaitlin J. Cook: That actually all of these
Kaitlin J. Cook: Sort of single a single particle states are actually really important
Kaitlin J. Cook: Producing the halo structure that we see.
Kaitlin J. Cook: Well, I really like is that this is actually a parent in our experimental data.
Kaitlin J. Cook: So against Colombia Association cross section that you've seen a bunch of times. Now it's a function of a relative energy
Kaitlin J. Cook: So that blue line is so the dotted line is the calculation with 0.5 MTV and separation energy and the full model calculation includes all the states it's doing a pretty good job.
Kaitlin J. Cook: But then if we remove and make it a parody states and basically to say okay all has to be a slave and
Kaitlin J. Cook: Then omega party configurations, rather than we see
Kaitlin J. Cook: That the sign line here. Now what's interesting is forgiven nutrient separation energy that have the one transition strength. So this calculation is actually got a large or small suppression initiatives or point three, maybe just to get us somewhere close to the experimental data.
Kaitlin J. Cook: And receive our peak is is maybe you can sort of tune it so hits the peak sort of below one. I'm a Weber's need to go above one Nev it really drastically files to explain our experimental data.
Kaitlin J. Cook: So what I quite like about this is that means that even though that were were sort of relatively uncertain about any chance depression energy, we can still say something about the diet and correlations from our experimental result.
Kaitlin J. Cook: Okay. So just to summarize, and then I'll talk about the outlook to summarize
Kaitlin J. Cook: Colon breakup cross section, it's sensitive the halo properties and nuclear. This is sort of complicated for teacher on hell is where we see the effects of the final state interaction and the neutron
Kaitlin J. Cook: But it's a sensitive product. So then to firmly identify whether or not born 19 has a halo. You mentioned reactions before 19 on carbon and loaded targets at three can using a bigger spectrometer and summary.
Kaitlin J. Cook: And we measured the exclusive as well as the inclusive cross sections for the production of born 17 and boring 15
Kaitlin J. Cook: Exclusive measurements are we mentioned the nutrients in coincidence allowed us to extract the colon breakup component of what we saw when we did that is a strong low lying a transition that's consistent with having a well developed hello structure.
Kaitlin J. Cook: So after that, that's a sort of key experimental result.
Kaitlin J. Cook: We could then interpret it with Model three body mental calculations. So we found consistency with a new transitional age youth 0.5 and EV
Kaitlin J. Cook: We saw a substantial S wave configuration as well as well developed Dinesh one correlation and we have experiment results and the shape of a spectrum is sensitive to these things.
Kaitlin J. Cook: What's interesting. So what's the lessons and this will be outlook is that our work largely disagrees with the previous investigations wherever they took the reaction cross section.
Kaitlin J. Cook: And the attorney terms of fresh energy, put it together with a to buddy treatment and a static get to the distribution. And so there shouldn't be much higher than it should be all the way
Kaitlin J. Cook: And this is basically to the fact that we have these simplified models and this has been pointed out previously, but it's less than that per
Kaitlin J. Cook: Se but it's less than that good models are important if you're considering or if you're trying to make determinations based on some of these pieces of information like the reaction cross section and the and mass
Kaitlin J. Cook: So I'm calling dissociation is sort of gives us a relatively model independent tool for Alex identifying halos because all you gotta do is you're going to see a large per section. Unlike competitor carbon at low relative energies.
Kaitlin J. Cook: And then we just need model sort of finished our understanding of that.
Kaitlin J. Cook: It would be very interesting for me. If we had a high precision mass measurement for born 19 and born 17 that got us a better separation energy
Kaitlin J. Cook: This would be nice, because we saw that our experimental results sensitive to a scattering life support and 17 plus n, which is interesting for the physics.
Kaitlin J. Cook: And it's also sensitive to the dining room correlation. So once we have a precise suppression and energy, we should have pinned on the amount of damage and correlation that can be occurring based on that.
Kaitlin J. Cook: List. It's also interesting as a sort of feature perspective, because as we're getting heavier and heavier along the new 205 or something, get more and more complicated nuclei.
Kaitlin J. Cook: For 19 is a good first case of that because born 19 is built on born 17 self bromine and itself really bound. It's also possibly deformed.
Kaitlin J. Cook: Based on AMD calculations and that sort of not taking into account nice bottle calculations and we should look at.
Kaitlin J. Cook: So there's there's lots more to do, and certainly more examples of mocking up on Halo is a useful. So this is, in fact, only the third experiment.
Kaitlin J. Cook: Where we have a sort of classical to nutrient halos. We've got helium, helium six looking 11 but I thought, we've got brilliant 14 but it hasn't been sort of as widely looked at
Kaitlin J. Cook: And now for nine King, so it's nice to expand our palate of multi nuclear halos try and make better models and understand what's going on in a more sophisticated way.
Kaitlin J. Cook: Um, so with that I'm out of time, so I'd like to thank the collaborators. So this experiment was part of the summer day one experiment back in 2012 so I wasn't a part of that. So most of the collaborators. Here we're part of that experiment.
Kaitlin J. Cook: I'd like to thank so that experiment, the theoretical support came from which you have, you know, who's now at Kyoto University.
Kaitlin J. Cook: And kazuki Ogata at a certain universities that have been assigned. Did everybody calculations and I got a son did a ticket CC calculations.
Kaitlin J. Cook: also like to thank kind of set them aside for my first for this work and the funding was in the USPS so if anyone is interested in doing.
Kaitlin J. Cook: Work for any young people are interested in doing work in Japan. This is a postdoctoral fellowship scheme that's open to people who are explicitly not Japanese. So if it's something I wasn't aware of as a PhD student. So this is to give you that option.
Kaitlin J. Cook: So, thank you.
James Smallcombe: Very much.
James Smallcombe: That was great. So now we come to five questions. So as I said before, if you look in the park participants menu. There's a little raised hand button where you can raise your hand or you can also ask questions in the text chat box on the bottom. And I'll read those out.
James Smallcombe: While we're waiting for people to make questions in terms of moving on in further understanding night on 19 born. Do you think
James Smallcombe: The next there should be more experimental work done, or is the next step to maybe do more theoretical calculations without the shortcuts, like the the non attracting core
James Smallcombe: Museums would be good.
Kaitlin J. Cook: But the good so mass measurements are really important because they they can be basically a free parameter and it's mental calculations. I'm getting rid of that would be really good.
Kaitlin J. Cook: So from the experiment mental and I think a mess. Measurement would be really, really nice experimentally. Also, we should say something about the halo structure born 17 so we're gonna skip the step in this experiment by doing for 19 before you do born 17
Kaitlin J. Cook: So I mean that data is actually in this experiment. So it would be good to someone to get out.
Kaitlin J. Cook: But yes, in theory, putting some Court's attention in there would be really good. There's certainly a lot of the body mental states.
Kaitlin J. Cook: In the
Kaitlin J. Cook: Sustainability models rather on the market and, as in lithium 11 I think people will want to apply them for 19 and i think i can tell us a lot of what's going on. Oh, more about what's going on.
James Smallcombe: Thanks. Okay, we'll go over now to fill and then after that, we've got a text question to fill. Please go ahead with your question.
Philip Adsley: Hello and thanks very much that it was super interesting and something I know nothing about. So
Philip Adsley: So the first question I was going to ask was, is it worth looking at. Boron 17 but you, you just answered that. So,
Philip Adsley: The second was about this this structure at the high relative energy is that which you said you know isn't as well described by the models to predict it.
Philip Adsley: Is this likely an experimental failing or a theoretical failing. Is there some possible the possibility of of the high relative energy being things which aren't well described by
Philip Adsley: From additional nuclear processes or something that
Kaitlin J. Cook: Yeah, so this is very much likely because we don't. So these model calculations aren't really doing this the nuclear component because what we've done is
Kaitlin J. Cook: We've extracted the column component and then we're all we're doing is calculating a call on component. In fact, we're capturing the wind and putting it through the code on record.
Kaitlin J. Cook: Any
Kaitlin J. Cook: So that's a very sort of
Kaitlin J. Cook: It's a, it's derived quantity right what we measure ultimately is the breakup on lead
Kaitlin J. Cook: And that's going to be some, you know, some like it's not just a it's it's not just you have the coolest and you have a nuclear you have interactions between Coleman nuclear break up right
Kaitlin J. Cook: And this is sort of not
Kaitlin J. Cook: Always well considered in when we try and remove the colon breakup competitors have done the best we can. But what you really want to do it and ultimately really want to do is you want to calculate the
Kaitlin J. Cook: Total breakup cross section on lead like you don't want. And that's bit more difficult to calculate
Kaitlin J. Cook: OK. And that's why you sort of and and you know ultimately also what we like. That's for me as a person. I think we should just cut the lead the lead structured people want the easy ones, though, and this is how we get the big one. Okay.
Thanks.
James Smallcombe: Okay, we've got a question in the chat from Andrew and Dr. Who says ever most states we mentioned several times, what are they and what do we learn about them from 19 boron data.
Kaitlin J. Cook: Yeah, that's a good question. I really spend much time on it. So f of states are something that
Kaitlin J. Cook: Come from
Comes from atomic physics.
Kaitlin J. Cook: And it's a situation where you have
Kaitlin J. Cook: Comes from theory. Originally, it's you have a buddy system where
Kaitlin J. Cook: To body subset of it. So in this case, maybe the Bourne 17 plus a neutron approaches infinite S wave scattering length. So yeah, it has a very, very large infinitely large interaction radius almost
Kaitlin J. Cook: So this is sort of something that we try and realize experimentally and there's been attempts in in atomic physics and nuclear physics, of course, because this is
Kaitlin J. Cook: Ricardo control the systems, what we're doing is we're looking for these states in nuclear systems. So we're looking for nuclear systems that have incredibly long scattering lights.
Kaitlin J. Cook: Now, this probably isn't going to be occurring and bro 19 but born the measurement of born it
Kaitlin J. Cook: does have the longest. So the most negative scattering links that we've ever seen submitting probably about minus 100 centimeters.
Kaitlin J. Cook: So it's a way of sort of looking. It's sort of a chance to maybe look at these structures and born 19
Kaitlin J. Cook: So the second part of the question is what we learned about them from born 19. So I showed the condo association cross section or maybe it's easier seen in the be everyone
Kaitlin J. Cook: Has some sensitivity to the scanner life. And if you are able to control things like the new transportation, energy. So if we had a very nice to have a measure
Kaitlin J. Cook: Of the born 18 plus neutron. So the poor and 17 plus neutron scattering like
Kaitlin J. Cook: This is actually also some work that we AM THE DAY ONE collaboration did by just looking at the bar 90 in the bar and 17 plus neutron coincidences on the carbon data. It's not part of my work, but part of Savannah bonds PhD thesis and I think he's writing a paper on it.
James Smallcombe: Okay, thanks. Monica and Chandler, so then another question from Bill gladly. Go ahead, Bill.
James Smallcombe: I'm sorry, Bill, you've got some really bad feedback there.
James Smallcombe: You may be
James Smallcombe: A bit better
William Gelletly: Okay, maybe I'm too close to the computer.
William Gelletly: Political identification plot but love any nuclei. You didn't see that you expected to see. And then the second question is not long till effort start something
William Gelletly: New plan to follow any of this up and are there some things that you might be able to do better.
Kaitlin J. Cook: Yeah, those are two good questions. So in the political ideas spectrum. I think we, we certainly saw everything that we expected to see. I don't think I was too much in a way of of surprises there.
Kaitlin J. Cook: So, um, that's a very quick and flip it answer, but I don't at least in my experiment. So this is a very long experiment with a lot of different magnet settings.
Kaitlin J. Cook: I really can't speak to all of the settings and whether or not we source we didn't see things that we see. I think certainly for the maybe for some of the charge exchange work the cross sections weren't quite what we expected.
Kaitlin J. Cook: For effort. So if it's coming online, which is really great. And in the future, we'll have the hrs our high rigidity spectrometer.
Kaitlin J. Cook: Which will be sort of not a competitor.
Kaitlin J. Cook: competitor to summarize like web, it's a similar device to samurai
Kaitlin J. Cook: And that's still a few years down the pipeline. Up until then, we still have the sleeping bag and the Mona Lisa device. And that's, in fact, where the work comes atmosphere came from with born at
Kaitlin J. Cook: I'm personally not intending to do anything about it because my interest is more infusion. This was a weird reacted weird sort of structure moment for me.
Kaitlin J. Cook: But I would be surprised if I didn't do anything like this in the future that that'd be part of the Mona Lisa. Great. And hopefully I'll get a chance to pitch and with that.
William Gelletly: Would be better. I
Kaitlin J. Cook: Will be there. So, yes, yes. That was a good question. At the moment, the Mona Lisa device with the super bang it doesn't have the same kind of acceptance or the same kind of resolution or efficiency.
Kaitlin J. Cook: As semi Mona Lisa might be a little bit higher efficiency, but I'm not sure we have the cross talk quite that with is in the same way. So they haven't done so much. They don't have intensity with effort, they'll have the intensity, that's for sure. And hrs
Kaitlin J. Cook: Should be at least as good as summarize
Kaitlin J. Cook: They are also at the moment planning a upgrade to or maybe not an upgrade a next generation neutron
Kaitlin J. Cook: Detector that will be really nice. But that's in the planning stages. So I can't really speak to the difference and credibility between samurai
Kaitlin J. Cook: And and this new device and the other. So just to say, then the other cool thing would be Norland at GSA now Norland it checked his DSI
Kaitlin J. Cook: In principle has much better angular resolution or like granularity rather in a new trends and each one was
Kaitlin J. Cook: And it has been our efficiency as well. So for multi so what they really nice to do it and what people are trying to do condition, for example, are doing more and more nutrient coincidences. So, the moment I think to new trances about
Kaitlin J. Cook: Getting a sort of spectrum for multi neutron or more than two new trends is very difficult. And that's what I think about like stalking things like Norland and nebula together and we're going to be more of that in the future.
William Gelletly: Thank you.
James Smallcombe: Okay, we've got another question from my home Yang. If you'd like to go ahead
ZAIHONG YANG: Okay, thank you. So I have a question about the maybe discuss it.
ZAIHONG YANG: You determine the distance between the call and the two neutrons from the p one strings. So I may not follow the details from your city calculation.
ZAIHONG YANG: It just seems main contribution is from the S wave and the wave strangely like we've opened the maybe 35% right then. You mentioned the you determine is called neutral distance from this by scanning with some everybody model.
ZAIHONG YANG: To do we need to consider is 35%
ZAIHONG YANG: For the as well as your three body model. I mean, simple uncorrelated three by the model, you're assuming, like
ZAIHONG YANG: One of the Newtonian one more configuration and 100% right yeah
Kaitlin J. Cook: OK. So the model that we use is the same calculation that determine for 35% occupancy of the slave. So this model calculation is the sophisticated one from heaviness and that includes these things.
Kaitlin J. Cook: So the reason. So the reason that we scaled from the food on a model is the alimony model up about the politics question principle which you don't get when you use the cluster something wrong.
Kaitlin J. Cook: So basically the procedure is quite simple. What you do is, is you take the neutron core distance from the model.
Kaitlin J. Cook: And you take the be of eight one from the model, you take the be have a one from the experiment. And they say, Okay, these are pretty similar, but not quite the same.
Kaitlin J. Cook: So then you scale the BV one from the experiment and the be everyone from the theory. And so this is your scaling factor for the for the ratio or for the distances with some factors and that basically works as a nice as a reference for that if you want, I can go back forward.
Kaitlin J. Cook: So let me go back.
Sorry.
Kaitlin J. Cook: So if I go back
Kaitlin J. Cook: Forward.
Kaitlin J. Cook: Yeah, there's a paper from Espenson
Kaitlin J. Cook: The sort of puts that sort of compares the results you get from the cluster some all just sort of the traditional way of getting this our ladies Connie Chung distance. So that's cool.
Kaitlin J. Cook: Cool to nutrient distance
Kaitlin J. Cook: And compares it to what you get from the body model. So if you're interested. That's the reference, if you want to read more. So basically we're using the exact same free body model that includes that 35% S5.
ZAIHONG YANG: Okay, I understand. Thank you.
James Smallcombe: Okay, if we have any more questions, you're welcome to ask them. Anybody who's struggling with the raise hand button, you're welcome to unmute yourself and ask the question now.
James Smallcombe: I don't see any. So I think we'll end the questions there and say thank you. Caitlin for a great talk.
Kaitlin J. Cook: I thank you for having me. I'm
James Smallcombe: Very pleased to have you. And thank you everyone for joining us, please do come back for us to play later in the week on Wednesday we have student talk session, which
James Smallcombe: I think we've got Russian Liverpool this week talking about
James Smallcombe: Letters spectroscopy yourself as a student or particular encourage your students to come support that pays for that on Wednesday.
James Smallcombe: But make sure you use as a different link for the students sessions in the emails and the website and then come back on Friday. We've got Rachel on company from the University of Glasgow.
James Smallcombe: It's going to be talking about exploring the structure of Nissan's be tagged deep and artistic scattering decimal have
James Smallcombe: Some really high quality stuff there.
James Smallcombe: Okay, so yes. One final. Thank you all for joining us. And thank you again. Bye for now.
Bye bye.