WH11NE- Sunrise: We don't let's see what's down
WH11NE- Sunrise: there we go. Okay. So the 1st thing I thought we should talk about is this entanglement right? We're going to talk about entangled top quirks to all be on the same page about entanglement. So right? Entanglement is a purely quantum mechanical phenomenon. You cannot observe this in classical physics. And so what I'm showing here is a quantum state which is not entangled. It is a separable state here. It's a product of 2 different states. And so if I perform operations on A here, this is not going to defect anything about B
WH11NE- Sunrise: and when you 1st start thinking about entanglement. I think it's very clear that, you know, it's we're really talking about correlations. Right? Entanglement is a statement about how 2 different substates of a of a quantum state are correlated.
WH11NE- Sunrise: but something that you probably will also have encountered when you think about entanglement is that well, classical physics is correlated too. So there has to be something more here about correlations than when you talk about quantum entanglement than just pure classical correlations.
WH11NE- Sunrise: And I think you know this is made the clearest when you're discussing a simple 2 level system, 2 of them. Okay. So these are also referred to as qubits. And so I can have 2 qubits A and B, and they can be in a superposition of anticorrelated states. So what do I mean by that is that it's something like this. They're in a superposition. They're definitely anti-correlated. But I can't tell which you know. Spin A is in which B is in.
WH11NE- Sunrise: And so you know that this is the type of correlations that we're talking about when we're talking about entanglement. Now.
WH11NE- Sunrise: if you're not really sitting easy with this, that's okay. You're in good company. This is not a trivial thing to understand. And there was this famous argument put forth by Einstein, Pinofsky, and Rosen, which they said that. Okay, the reality of measuring P. And Q. Depending on the process of this measurement carried out on that 1st system. A.
WH11NE- Sunrise: You know that that does not make sense, because how could it disturb the second system? They're they're completely separate. Alice is in Wonderland
WH11NE- Sunrise: and Bob Marley's in Jamaica, right? They're not interacting anymore. So how can me, what I do with a affect? B here, right? The outcome here. And they said, a very strong statement. No reasonable definition of reality could be expected to permit this. And this was almost a hundred years ago, 90 years ago, now that they 1st put forth this argument, and it wasn't until Bell, about 30 years later, who really started understanding this true argument.
WH11NE- Sunrise: and he said that that particular interpretation has indeed a grossly non-local structure. This is characteristic, according to the result to be proved here of any system which reproduces exactly the quantum mechanical predictions. What he's saying here is that you have to assume 2 things right, you have to assume realism and locality. Okay, now, if you believe in realism, meaning that there are some of these hidden variables that you then can use to predict something
WH11NE- Sunrise: you have to forego locality right? And so, if you want to believe in this hidden, variable theory, it has to be a non-local theory to actually produce the correlations that quantum mechanics should produce.
WH11NE- Sunrise: And if you still find this not true, really, I think it isn't, it's so important that the Nobel Prize in physics was awarded this in 2022. It's really changed a lot of how we understand quantum mechanics. And also, people are now building devices that are leveraging quantum mechanical phenomenon to do computing in new ways that are not possible classically. So, I'm just showing a handful of the different quantum computing devices here.
WH11NE- Sunrise: This one is really exciting. I do find this work also really exciting. If you want to talk to me more. But I won't really talk about that today. I do have some work on that. But what I really am interested in talking about particle physics is, can we learn anything more about quantum mechanics at a particle quiet? I think this is a really cool question to ask, and I don't think we're there yet. I'll definitely be showing you what we're starting to do. But I think there's still lots
WH11NE- Sunrise: more that we need to do when trying to ask ourselves, is there anything we can really learn here about quantum mechanics at a particle?
WH11NE- Sunrise: All right. So I think most of you are maybe familiar with this. But this is right on my lab. So this is the Lhc 4 different experiments at the Lhc, and this is specifically with the Cms detector that I'm talking about today.
WH11NE- Sunrise: And so yeah, top quark physics. Here, the top quark is a very unique particle. It's extremely massive. This is the mass of the top quark from the recent combination, and because it's so massive it decays very quickly. It actually decays so quick that it really before it really can hydronize, and also way before spindy correlation effects taken to play. So what that means is that you can actually study quasi airport physics here, when you study the top quark
WH11NE- Sunrise: the also, the unique thing about the top port is that we produced over a hundred 1 million thus far at the Lac. So you can really do precision physics with the top.
WH11NE- Sunrise: Now, when we talk about spin correlations, it gets a little bit more complicated, but you can understand spin correlations and pair produced, depending on 2 things. Well, maybe 3 things the production mode. So whether you're initiated from boom or quark into quark annihilation, but then also effects of higher orbital momenta. Now that is manifested in the dependence on the scattering angle
WH11NE- Sunrise: and the 0 mass frame of the Tt. Bar system and the invariant mass of the Tt Bar system. Okay, so spin correlations are dependent on these 2 things. Now, as I mentioned, the top part lives for a very short period of time, therefore I cannot set up like a certain relax apparatus to measure the top port spin. Right? That's just not possible. So what does that mean? How can we actually know the spin? Well, the spin is actually fully preserved in the charge up time
WH11NE- Sunrise: and down type, quark decay products. So I'm showing that here, and these are your Leptons. And here in some of the tonic, you would have to look at the up type. Quark down, type work. Sorry. And so what that means is that we can infer the spin indirectly
WH11NE- Sunrise: from the decays of the boson, due to the fact that the charge 3 boson maximally violated. Cp, now, typically, when you do spin correlation measurements at the Lhc we measure them in what's referred to as the helicity basis. So I'm showing this is the helicity basis here on the right. It's the Krns forms of orthonormal basis for this measurement. We actually don't have to rely on the helicity basis. It's completely basis, independent. However, a lot of what I will talk about
WH11NE- Sunrise: you. You will see some basis notation. So I will go through this a little bit. Just so that way, you understand. But it's it's not maybe too
WH11NE- Sunrise: important for this measurement. So to build some intuition of like, how we can actually measure correlations, and how that is actually performed at the Lec. I wanted to talk about that just for a couple of slides here. Now, this is based on a prior result from 2019 with the 2016 data.
WH11NE- Sunrise: But you know, nothing really changes. So let's make quotations. So okay, so the the spin density matrix of the top quark antiquark system can be broken down into a fourfold angular distribution. Okay, so this is your fourfold angular distribution here, these Kappas. These are your spin analyzing power. What that means is, you know, given that we're measuring these angles with
WH11NE- Sunrise: some, vector how? How well can you reconstruct the spin of the top fork from that. Vector and, like I mentioned, we're using the Leptons or the downtime forks for Semitonic. We're doing diatonic here. Those Leptons have a spin analyzing power of one. What that means is they're they're perfect at analyzing the spin of the top fork. Okay? So if you see in my notation. Oftentimes I drop these capitals, and that's because they're one or the diatomic. Okay.
WH11NE- Sunrise: and here you have your polarization vectors, your B and your B bar. Here is your spin correlation matrix. Since we have spin, one half particles, qubits, they have 3 spin polarizations, and then, therefore 9 correlations. And there's 2 particles. So you have 15 coefficients. So if you want to know everything about the spin of the 2 qubit top quark antiquark system, you have 15 things that you need to understand. Okay, now, this is, I think.
WH11NE- Sunrise: non-trivial, like, if you show me this 4 point angular distribution. I don't think I could tell you what the polarizations and correlations are. It's really messy. But what you can do is you can integrate it. Okay? And if you integrate out to these one dimensional, normalized differential cross sections, they actually become pretty simple functions of the coefficients. And then, therefore, it's easy to just look at a differential cross section and say.
WH11NE- Sunrise: know what the correlation is from that. Okay? And and if you don't see it yet, I think you'll see it in a couple of slides.
WH11NE- Sunrise: So here I'm showing the polarization. So the Sam model is Cp, even so, you don't get any polarization for top works at the Lac. And what that manifests at is that the Parton level that means you have a 0 slope
WH11NE- Sunrise: in in this angular distribution here. So B, here is your polarization. You just say, that's the slope of this distribution here. Right? Okay? And and so I'm showing here. This is your normalized differential cross section. And then this is your angle to angle between the left arm and and your axis, and the frame of reference of the parent top board.
WH11NE- Sunrise: which, like that's related to this felicity basis this part here. But the important thing to know is that the detector level, the reconstruction level, it's not flat anymore. Right? So this is because of migrations, acceptance and efficiency. Right? So all these things matter if you naively just tried measuring the polarization at the detector level just by looking at this distribution, you would, of course, get the wrong answer. Now, when we did this measurement, we saw they're all consistent with 0. So that's good. Standard model is a standard model.
WH11NE- Sunrise: And here, okay, this is what the correlations look like. So it's a little bit more of a complicated function. But in the end it's still
WH11NE- Sunrise: you can see that it's related to this asymmetry. Okay? And so this this asymmetry in this distribution relates to the correlation. So if it's if it's symmetric, then it's uncorrelated, and if it's asymmetric, then it's correlated, and you can see that there is an asymmetry in this distribution at the parfan level. It also still exists at the reconstruction level. So I guess that's nice to see. But you can see that manifesting here. So this is this distribution
WH11NE- Sunrise: would be used to compute the Ckk correlation coefficient. And you can see here that indeed, you see, there's non-zero correlations. And this is a remarkable thing about the standard model and the standard model. You have no polarization. Do you have correlations for the top organic work system?
WH11NE- Sunrise: And so that that in itself maybe seems a little not trivial.
WH11NE- Sunrise: Now, when we start talking about entanglement right now, this was just correlations. We haven't talked about whether these correlations are quantum mechanical right? And to say that kind of a statement, you have to be a little precise. So typically, you know, when we talk about a state here like this is a separable state, right? It's not entangled. This is really a pure state. Okay? And so pure states
WH11NE- Sunrise: which are here. If you're entangled, you violate Bell's inequality. This is, if you, if you really want realism, you have to accept the non locality, etc.
WH11NE- Sunrise: However,
WH11NE- Sunrise: in general, quantum mechanical systems are not pure States. What does that mean? Well, that means that you could be a mixed state, and a mixed state is a collection of pure states in a statistical like ensemble right? I have different probabilities of these from pure states, and I mix them all together, and that's my mixed state. Now, when we have mixed States, we have to rely on a different formalism of representing them, which is referred to as the density operator. So at the Lac
WH11NE- Sunrise: reproduce top quarks in a mixed state. You can understand this naively, because we have a blue one initial state, you can bar initial state. So already things are different here, quantum mechanically. But you also have order, angular momenta dependencies, so we can use. I'm sorry we can write the density operator in this way. Here you're using what's referred to as the poly spin decomposition. And so these, these are your poly matrices here.
WH11NE- Sunrise: And here you can see your polarization vectors and your correlation matrix. So that's how we can represent our density operator here. And what you have to ask yourself now is okay. Right? So now I have mixed states. I have this whole hierarchy of correlations that I can now access. But I'm wanting to ask a question of whether or not given this density operator, whether it's entangled.
WH11NE- Sunrise: And you can do this by constructing what's called an entanglement witness. Okay, so it's going to be some operation on your density matrix that returns a number, and that number tells you how entangled you are. Right in a pure state. You're either entangled or you're not right. You're either a classical thing or a quantum mechanical thing if you're entangled now here, though, you can think of it as thinking
WH11NE- Sunrise: degree of entanglement, where, like, you may be maximizing your entanglement when you're violating bell inequality, and and you can maybe only have discord or possible correlation. So that's what an entanglement witness is really getting at here.
WH11NE- Sunrise: Now given an arbitrary density matrix, it's hard to show that it's separable. But you can. Actually, there are methods to show that it's not separable.
WH11NE- Sunrise: and that we use what's called the Perry's-forideki criterion. Okay? The Perry's-forideki criterion says that given a quantum system, a density matrix of mixed state, if I perform an operation on the subspace of it. Okay? And after I perform that operation on my subspace, if I no longer have a valid density operator, then that was an entangled system.
WH11NE- Sunrise: The operation has to be a specific operation. Usually it's the partial transpose. So if I do, the partial transpose of my density matrix, and I see that this is no longer a density matrix, meaning that I no longer have unit trace, no longer hermission, or all the Eigenvalues are no longer positive. Then this is an entangled system. Okay, this is also referred to a positive partial trace
WH11NE- Sunrise: criteria
WH11NE- Sunrise: because of that. Okay, so that's what you can do. And so you do that to that prior density matrix that I showed you. And you do a bunch of algebra. And because the top parts aren't polarized, etc, you can actually, everything simplifies to down to just this. So here's your entanglement with this. Okay, it just is related to the sum of 3 of your correlation coefficients in a specific manner, minus one
WH11NE- Sunrise: has to be greater than 0. That's it. Now, the interesting thing is that low in the mass of the Td Bar system. These Ckk and Cr values, they take on specific value, positive. And what that means you can drop this absolute value sign. And now entanglement is related to the trace of the swim correlation matrix. The trace of a matrix is basis, independent.
WH11NE- Sunrise: and the and that is reflected in the manner that I can access the trace through this D spin coefficient through a single differential cross section.
WH11NE- Sunrise: This angle 5 is between is the angle between Leptons, where Leptons have been boosted into the parent top frame of reference. So all I have to do is measure this angle, and I can get out entanglement
WH11NE- Sunrise: right? So I think this is really remarkable. It really works out very nicely. So if I can measure D's being less than negative 1 3, rd then I can say damn thing.
WH11NE- Sunrise: Alright. So just measure deep, that's all it takes alright.
WH11NE- Sunrise: Now, how can we actually discover entangle like I mentioned? There's a phase, space dependency here. You're not entangled everywhere in the top work, antiquart system. And so you can see here. These are your 2 different entangled regions. In this region you are separable. And so you're either entangled in the low, invariant mass region or in the boosted region, but also centrally okay. And now for this analysis, we'll be targeting the low, invariant mass region. Sorry? Can I ask a question? Yes.
WH11NE- Sunrise: physics form historically, has been interactive. So I wanted to. So this is super interesting, obviously.
WH11NE- Sunrise: could you give us qualitatively.
WH11NE- Sunrise: I'm missing. Why is it the entanglement? Depend on the mass invariant mass of your system? No, absolutely absolutely so. I think it's more easily to understand the threshold region. So what you have is initiated production. Now the gluon right? It's a massless spin, one particle. So it can't have the longitudinal polarization. Right? It's like a photon. Basically.
WH11NE- Sunrise: I can only have transverse degrees of polarization. What that means is if I want to create a Td Bar system which is spin one half. I have to have the spins of my gluons aligning in certain ways, so that way I would have like a spin singlet
WH11NE- Sunrise: right? And then, now that I can only produce spin singlets, those are maximally entangled. So at exactly threshold, you're just going to get one to spin Singlet. Tt. Bar pairs which are maximally entangled. However, as you start adding more energy that that spin angular momentum can translate into orbital, angular momentum, and then you lose this spin singlet property. So that's where you start getting into separable.
WH11NE- Sunrise: Now, in this, in the boosted region, they're just like flying back to back. So there's really no April momentum anymore. And that's why you get that. And that becomes a spin trip.
WH11NE- Sunrise: Okay, excellent. Thank you that was, yeah, super quick. No, it's it's really beautiful. I think it's really cool. Alright.
WH11NE- Sunrise: And so, yeah, so this is our event selection. Like I mentioned. We do diatonic. This is with the 2,016 data. It's a very standard event selection to absolutely charged Leptons. We make sure that they're tight Leptons, Pta cuts. We do reject low. Mlbr. This to get rid of your like your hydro-hydronic resonances at Low Mlbr. Sorry another one dumb question.
WH11NE- Sunrise: No, this. This is your invariant mask. I'm sorry. Sorry. What's the 400 line? This is actually, you'll see. This is where we we measure in, and I have another thought on that. So yeah, the dashed line is telling you where we measured and the the dark lines are telling you your boundaries from Yup.
WH11NE- Sunrise: So you're right above the Tt. Bar threshold, right above it, and we'll talk a lot about that. Because, said this is easy, because it's 1 thing, but it's not so easy because of that. Absolutely, absolutely
WH11NE- Sunrise: alrighty. So yeah, so low. L bar. We also require 2 at least 2 anti-k jets. We have P. Tagging jet cleaning. Oh, yeah. And then for the same flavor leprons. We also have additional selection criteria, and that's to reduce back the drawdown background. So we have, like a missing energy transverse of greater than 40 Gb. Requirement. And also we exclude the Z Peak window.
WH11NE- Sunrise: and then also, which I'll talk about. This is some detail about the Kinematic reconstruction. Since we have to measure the angle of the left humps in the top court frame of reference we have to fully reconstruct the top court. And so sometimes that reconstruction fails. And so we also have required the events to pass this reconstruction.
WH11NE- Sunrise: Oh, yeah, that's the next slide. So here's the, here's the reconstruction. And so this is the the core of the reconstruction algorithm that we use.
WH11NE- Sunrise: It's an analytic method. You can see that. You know, you just basically use your 4 momenta equations. Know that I need to make a W and a top quart, and I'm solving for the neutrino. Since it's a diatonic, I have 2 missing 2 neutrinos that I need to reconstruct. Assume they're massless for us. That's okay, I know some of you probably want to know what the mass of neutrinos are. I cannot know
WH11NE- Sunrise: that. And so, okay, so I can just solve these equations. But the issue right? I have 6 unknowns, and you know I need 6 equations then. And I really don't want to know. You know, 2 equations, these other 4 equations. I don't really know the mass of the top quark in the WI know the pole mass, but it's a bright Wagner, etcetera, so that becomes one of the assumptions that we have to
WH11NE- Sunrise: deal with with this reconstruction. But you can see this is a published paper that looked into how to reconstruct this. Since you get a quartic equation in general, when you solve this, you can have up to 4 different solutions. The way that we resolve that ambiguity is by picking the lowest invariant mass of the conflict pair as the solution.
WH11NE- Sunrise: Now, I have this little diagram here, and that's important for the next slide, because this is what we actually do in terms of the reconstruction. So the core of it is this little box here which is doing this analytic solution. But, like I mentioned, we have to deal with the fact that the W. Boson actually comes from right big. So we do sample that. But we don't sample the top part just because it becomes too computationally expensive. Now you're talking about having to do so many solutions.
WH11NE- Sunrise: and then on top of that. When we have a single solution, we weight it based on the mass of the Mlb distribution. So that's why we call this the Mlb method.
WH11NE- Sunrise: But then, one last thing that we do to improve things is that the Lepton and the B. Jets are smeared within their resolutions. So that way you do this 100 times, you get 100 different solutions. We weight it by the Mlb. And then we also do jet Parton assignment permutations that would maximize the sum of weights. So this is our top diatonic top work, reconstruction. This is actually a very popular reconstruction method. It's used by all of these analyses. I just gave you the caddy lines. But yeah.
WH11NE- Sunrise: alright.
WH11NE- Sunrise: And oh, yeah. So I am actually really interested in top of reconstruction. So I do have some other prior work on that. So if you're interested, feel free to ask. And we have seen that machine learning can, of course, improve this process. So all right. So, okay, so where are we actually measuring it? Like I mentioned, we do measure below 400 Mtp bar, but we also put a cut on the
WH11NE- Sunrise: the velocity of the beta of the Td. Bar system along the longitudinal and the Z direction. Now, why is that? That's because high, longitudinally boost Td bar systems are going to come from Qqbar. Initiated States, and they're not as strongly entangled in the threshold region so we can place that selection criteria to enhance the entanglement. So that's what we're showing here is this is the boundary for entanglement in this region.
WH11NE- Sunrise: and the dash lines are where we're selecting.
WH11NE- Sunrise: And then how we actually measure D is we're using a bin profile likelihood fit of the cosine Phi distribution in this region.
WH11NE- Sunrise: Now, this is how you do a bin profile likelihood fit. Now we use, combine, combine is a popular software in Cms to do bin profile likelihood fits. If you want to read more about. You can read here. This is how the likelihood in general is constructed for combined. So we have Poisson distributions.
WH11NE- Sunrise: and the number of expected events are dependent on 2 things, one are your unconstrained nuisance. Parameters are also often referred to as your parameters of interest, so you have, like a signal strength modifier a lot of times. If you're like trying to measure a cross section or put an upper limit on a process. Here, however, where we have. D. This is an unconstrained parameter in our fit, and we do not fit a signal strength. Here
WH11NE- Sunrise: we do have the cross section of all their backgrounds as nuisance parameters in the bit. And then the this, this Chi, these are your constrained distance parameters. So we have different priors for those, and have auxiliary measurements based on that, to to estimate what those priors are for all of our nuisance parameters, we have either log normal or shape, based priors.
WH11NE- Sunrise: And so one question you have to ask, though, is, how can you get like a variation of D right? Because that's what we're getting at here like, if you're measuring top part mass you can have, you can do. That's just a tutable parameter in your Monte Carlo. Right? I could say, this is my new top part mass. Now I can generate a new Monte Carlo, get templates from that, and and then do a fit based on that. When we talk about spin correlation. This is not just a tutable parameter in my mind.
WH11NE- Sunrise: Monte Carlo. I can say I want, you know, entangled top works. I don't want entangle top works, etc. And so what we relied on is that what you can change in the Monte Carlo is turning off spin correlations so you can turn off spin correlations in the Monte Carlo. And now the top works are no longer quarterly. Now
WH11NE- Sunrise: that means that D is 0. Right. Do you remember, it's a trace of the spin correlation matrix. So if I have no correlations, D is 0,
WH11NE- Sunrise: and I can then take my no spin correlation, sample, and my spin correlation, sample and mix them together to get any degree of d between d standard model and 0 right? But now we have the issue that. What if nature is more entangled than what the standard model predicts? Right? I need a way to measure that. So what we do is we just mirror the template. So that way we get a variation in D, that's continuous.
WH11NE- Sunrise: Now that assumes that there's nothing about part time, shower, position that knows anything about stick.
WH11NE- Sunrise: Yes, this is true, because you do have 2 different now, like mixtures, elements essentially that you're not mixing. And yeah, I mean, we do still use the same part on shower and everything. But of course, yeah, the fact that you turn off swing correlations.
WH11NE- Sunrise: Yeah, yeah. Now, we do have systematic uncertainties also related to the part time shower modeling as well. So but do you test that? Do you test that? You can take spin correlated and
WH11NE- Sunrise: on 4 weighted and with the right mixture of those get exactly the same result. Yeah, we've done like the linearity test to as like a closure to see. Okay, if I re rate the polarization just at the generator level and then get see if I do a new spin collation fit fraction fit. Do I get back that when we do so, we do these kinds of tests. Yes, but so those effects I'm talking about.
WH11NE- Sunrise: and I'm sorry the ones I'm talking about are not in the Monitor.
WH11NE- Sunrise: We don't track spinning position. We don't track. No, you're right. Yes, yes, yes, yes, absolutely.
WH11NE- Sunrise: And so this is getting to the point that was raised is the production threshold. There are modeling issues in the production threshold. So this is a recently published unfolded differential Cross section of the Mtd. Bar spectrum. And I'm blowing this up for you to clearly see. Is that what we are measuring compared to what we are predicting is clearly, there's some deviation here this one is for, like
WH11NE- Sunrise: top work, mass of 169.5, so I wouldn't look too much at that one, but you can see that our standard Monte Carlo generators are already in slight tension here.
WH11NE- Sunrise: and this is seen oop.
WH11NE- Sunrise: So this is seen across experiments, a Cms. Atlas and also across different decay channels. So it clearly is something interesting going on here. That's not in our Monte Carlo generators. And what that could be is what's referred to as Tom Ponium.
WH11NE- Sunrise: So the ponium is a hypothetical standard model resonance. It's in the production threshold region of the Td. Bar system. It is a spin singlet, which means it's maximally entangled. Okay?
WH11NE- Sunrise: And therefore, if I'm going to measure entanglement in this region, doponium might affect that, it will affect that really. And so here you can see a calculation. This was done using non-relativistic Qcd, and you can see that the color Singlet spin singlet contribution forms a nice little resonance in this spectrum.
WH11NE- Sunrise: And so we use our signal model also has a model for this company and grant State contribution.
WH11NE- Sunrise: So what do you mean? I mean? Harmonium isn't a special harmonium comes out of the stereo absolutely. This is this is Santa Mono residence. Right? So you said hypothetical. I mean, it either must happen or not, I mean, like, okay, if you assume Santa Mono. Sure, then it's there. But no one's observed tap onium. That's what I mean by hypothetical.
WH11NE- Sunrise: Yeah, it's expected, but not absurd. Is that clear?
WH11NE- Sunrise: And so this is what it looks like. If you want to create. If you include taponium and to pony, we also have to be able to vary the amount of spin collation here in the fit, however, we cannot mirror it, because, like, as I mentioned, this is a spin singlet, so it is already maximally entangled. And so that's where we get these variations from. Now we perform the fit, both including and excluding the possibility of there being this ground state to pony and uncertainties associated with it.
WH11NE- Sunrise: And so this is just showing what our distributions look like at the prefit level. So this is the Rmtd Bar spectrum, including the effects of torponium, and you can see that in this ratio plot. Here the orange is with the inclusion of topoonium, and the purple dotted is the exclusion, so it does boost the agreement within your uncertainty, but there still is some possible mismalling still going on. It's within uncertainty.
WH11NE- Sunrise: That's what I'm showing here.
WH11NE- Sunrise: Great.
WH11NE- Sunrise: And then this is our cosine Phi distribution. This is what we actually are fitting to determine the degree of entanglement. And so here you can see that when we do include tipoonium, especially for the high cosine Phi. But Cosine 5, and you do get better agreement. And then it's just worth noting that Magrath overall models this distribution better. But it's been seen that at least, Magra doesn't model other distributions better. So, yeah.
WH11NE- Sunrise: this is the full list of
WH11NE- Sunrise: correlation, the systematics and corrections that are being applied and showing the effect that each one had has, either on the overall yield normalization or the shape of the cosine Phi distribution. The shape difference. This is measured in terms of the asymmetry of the distribution, which is a way that you can get the spin correlation coefficient. Our leading systematics here are jet energy scale, the A to T normalization and the part time shower modeling. And we also have other modeling.
WH11NE- Sunrise: And then, after we do the fit, this is what it looks like. So you can see that our post fit is in well, agreement with the standard model prediction. We get about 2.5 3% more swing correlated Tt bar. So just slightly more than what the standard model predicts.
WH11NE- Sunrise: And so you can see, this is what the profile likelihood looks like when we do not include toponium. And so you can see that we have a two-sided expected limit well, beyond 5 sigma, when we don't include the effect of tifonium and uncertainties associated with it. However, like I mentioned, although we haven't confirmed the existence of toponium.
WH11NE- Sunrise: we still would like to know, since there is lots of uncertainty regarding the effect of tipoonium. And so, after we include toponym into the signal fit model. This is what we see.
WH11NE- Sunrise: and so you can see that the observed degree of entanglement. The observable does get better, closer in line with the expectation from the standard model. And you can see also here that the Topoonium normalization is our number one systematic in terms of the impact. And so we had a plus or minus 50% normalization on the cross section of Topoonium.
WH11NE- Sunrise: But, as I mentioned, you can see the other dominant systematics like Jess, other modeling effects like parts on shower electric.
WH11NE- Sunrise: And so, as I would like to just conclude here, you know, with this measurement we can now say that top works are entangled, and therefore what we've learned about the property of the spins of the top works is that they are quantum mechanical in nature. They're non-classical now, for some of you might say, well, yeah, it's a quantum field theory that's not too shocking, and I will agree there. Right like this is indeed we're talking quantum mechanics here, but now we can definitively say they are entangled.
WH11NE- Sunrise: The other neat thing I think about this measurement is that it's the 1st one to attempt to include the effects of temporium in the production threshold region, and we can see that this, including of this, is important. Your expectation shifts in terms of entanglement, but also your observation shifts. And I'd like to just say that we've done spring correlations for a very long time. Now this is not new in that sense, but it is a new way of looking at spring correlations. So I say, it's a new door into ocean physics.
WH11NE- Sunrise: And
WH11NE- Sunrise: oh, wait, that's not all. So after this, we focus this result, I did not work on this result, but I just wanted to point it out to you that we have now seen that there is a pseudoscular structure in the threshold region of the Mtb. Bar spectrum.
WH11NE- Sunrise: Now we've recognized that it is consistent with this ground state of the ponium interpretation, and actually we even measured that the cross section is 7.1 pico bar plus or minus 11%. However, we cannot tell what exactly is the nature of the pseudoscalar structure, and we also cannot say that this is a resonance, because our resolution in the Ftd. Bar spectrum is just too poor. You can't see that this is actually
WH11NE- Sunrise: a nice little resonance. So it really requires more investigation, both on the experimental and theoretical side, to really clarify. What is the nature of this structure? No, no, I did not fit the cross section of the ponium, we treated it as a nuisance parameter in the fit.
WH11NE- Sunrise: Here I only fitted the degree of entanglement. This was a follow up analysis after, you know, after mine that showed that we can actually say that there is something super scalar here.
WH11NE- Sunrise: But you just can't definitively say stuff when you admit that.
WH11NE- Sunrise: Yep.
WH11NE- Sunrise: And so this is just my personal viewpoint here. What's next after this right kind of like what I mentioned. I want to answer the question, what can we learn about quantum mechanics at a particle collider? And I think these are some 3 main topics. I'd love to see people look into more personally myself. So one is like, does the wave function collapse after the power? Ck.
WH11NE- Sunrise: this is something you cannot study in a tabletop experiment you do not have. You cannot study the decay of particles and the entangle. This is something we can only really do at the Lec. So it's a very unique thing experiment we can do at the Lec. We can also look for quality violations. I mentioned this hierarchy right? So that would be nice to see.
WH11NE- Sunrise: Maybe these quantum observables are sensitive to new physics. We're talking about constraining like Wilson coefficients, etc. It has been shown that at least entanglement does give orthogonal directions to others, measuring correlation, coefficients, and observables. So there could be other observables here that are very important when we're talking about doing Efd fits. And then, lastly, you can also look at other systems besides top works like Higgs and Ww. Hicks is easy.
WH11NE- Sunrise: So thanks.
WH11NE- Sunrise: thank you. And I'll open to questions.
WH11NE- Sunrise: I think you sort of answered this. But
WH11NE- Sunrise: but top quark spin correlation measurements have been going on for a long time, and one thing that's not clear to me is like, is this something? Is there something that fundamentally is different about the entanglement compared to spin correlations? Is it a matter of interpretation? It's somewhere in between. Yeah, it's somewhere in between. It's mostly a matter of interpretation. Where do I want to show this? Right. It's here we go. So like we've measured. Actually, D has been measured since.
WH11NE- Sunrise: Run one Cms 1st measure D and run one. However, we did not see that it was entangled. And that's because we didn't measure in this face-face region. It was slightly above that, like 450 Gb. I believe is what we measured it up. And so, yeah, it mostly comes from the interpretation side of things. And what I would like to say is that right. Think of it this way. We have this hierarchy of correlations
WH11NE- Sunrise: here and in this bell inequality violation. When we talk about measuring up in this boosted region. If you measure certain correlation values, you would observe basically the expectation value of violating Bell's inequality before these types of investigations into the pheno, you would never have understood that. That's what you're actually measuring. Right? So it is on the interpretation. But what I would like to say, I think it goes a little bit more important than that, because, if
WH11NE- Sunrise: measured, the certain correlation coefficients in a certain way, you could actually violate
WH11NE- Sunrise: quantum mechanics. You can exceed what's called this series inbound right, and if we would have not have done all of this, we would have not even noticed that was even a possible interpretation. Right? So now, I don't think we're going to do that right. That'd be ridiculous, I think. And you'd also probably assume there's modeling issues going on before that right. But yeah, I think most of this is related to interpretation. But also there are now new observables that we've never thought about measuring because of this. So that was
WH11NE- Sunrise: last slide. So like, for example, magic, there's this property called magic. But it's actually related in terms of for quantum computing. So in quantum computing entanglement is actually not enough for a quantum algorithm for not being classically simulatable. You can have these things called stabilizer states. And so in general, you want to know how magic a quantum algorithm is. Well, it turns out
WH11NE- Sunrise: that's also well defined for Td more systems. And you can measure the magic. Now, we're not going to build upon a computer with that force, right? So I don't even know what that means, really. But the important thing here for me is that I can test whether magic is sensitive to new physics, and maybe you would expect that like, why is entanglement sensitive in physics? Well, because when you have non-zero, Wilson. Coefficient values. You have separable states.
WH11NE- Sunrise: Right? So like like, we're using quantum information to come up with new observables which may be sensitive to new physics. And that makes sense because it's it's physics in the end. Right? So that's what I would like to maybe say with regards to that question that helps. Thank you. I don't think we really have a full picture yet. Yeah.
WH11NE- Sunrise: I totally have another much more mundane question. On your systematics.
WH11NE- Sunrise: Yeah.
WH11NE- Sunrise: here. Or do you want the other one? I know that I know the other one with the big giant table. Yeah,
WH11NE- Sunrise: I guess it's probably trivial. But you have. So you talk about shape systematics on Delta Phi, and
WH11NE- Sunrise: you have a bunch of different systematics that affect energy measurements, rate measurements. Do you worry at all about how well you measure the angle like the actual angles of the objects do you trust? Do you trust that that's going to be captured in the stuff on that list? Or do you look at it separately?
WH11NE- Sunrise: Yeah. So the angles, if you really think about that, that's going to manifest in the reconstruction, because we're doing the sphering of both of the angular and energy resolution to reconstruct the top quarks, and since our reconstruction is dependent on everything that does then affect your your
WH11NE- Sunrise: your your ability to measure distribution. I think you see that most easily in the just systematics being dominant because changing that energy, then, is causing you to you know, to have a different reconstructed top work, etc. I don't think I can necessarily see the angular one just from looking at this list. But 100 is manifesting in the reconstruction. And that's why I'm personally interested in doing better reconstruction methods. Yeah.
WH11NE- Sunrise: sweet, good.
WH11NE- Sunrise: Any questions on Zoom.
WH11NE- Sunrise: Can I ask you also another question about like do you have so any
WH11NE- Sunrise: issue with statistics that you know that, you know, looking forward or having more data. Yeah, absolutely. So
WH11NE- Sunrise: this one, yep. So in the boosted region, you definitely are going to run out of statistics right? And also with the dialectonic, since we're not doing we haven't actually an isolation cut right in the boosted region. Your laptops are basically inside of your top 10. And so you need top tagging methods to access that in the dialect on yeah, definitely, higher integrated luminosity is going to help here for bell inequality violation. People are saying, fame.
WH11NE- Sunrise: People run full higher than me. You'll have that. So I mean, that's like when you're talking about statistically limited here. That's that's what you're looking at now. Of course, I think there's still lots we can do experimentally to improve that. So I think I'm optimistic. But yeah, current projections are baby. For
WH11NE- Sunrise: yep.
WH11NE- Sunrise: think in your backup you have. Atlas also has a result. This one? Yes.
WH11NE- Sunrise: Do they assume the same? That's why you have
WH11NE- Sunrise: this big discrepancy is basically it's a point. They also they import like 3 different reconstruction techniques. Technically, they calibrate it to the particle level. So you can't really compare, because there's a particle level. But yeah, but the biggest thing here, I would say is that they don't include to pony. And that's why you see this. The
WH11NE- Sunrise: X back to this is the particle of reconstructed. Yeah. So this is particle level, reconstructed. D, this is data calibration data.
WH11NE- Sunrise: I thought, my memory is you showed that the
WH11NE- Sunrise: expectation depended a lot on top of you, but not the reconstruction which made sense to me. So I did have not necessarily so. The expectation here would definitely shift.
WH11NE- Sunrise: and the observation does shift a little bit here, let me for us. It wasn't as drastic now they do. Their cut on Mtd. Bar is less than 380 gev. So they're looking where more toponym would be sitting. Relatively okay. So it should be a larger effect here. But you can see that the expectation shifts to more entanglement, but also the observation shifts slightly. And that's because toponyum. The effect of toponium is different than the effectiveness of correlation
WH11NE- Sunrise: like we're doing the fit based on how much? No spin correlation fraction is changing the bit and toponium changes the D observable differently, slightly differently than than what the nose. That's why you get a shift in the observation as well.
WH11NE- Sunrise: Okay.
WH11NE- Sunrise: And that's mostly coming from the reconstruction, because the reconstruction sits at a very narrow threshold. Right? And so the reconstruction algorithm is is changing. The response of the D, the cosine Phi distribution to pony is different than.
WH11NE- Sunrise: yeah.
WH11NE- Sunrise: So a couple of questions here, you're using public? Hdq.
WH11NE- Sunrise: yes. So you're not using the one that has the more advanced version. Now.
WH11NE- Sunrise: No, no, we're not using Bb, 4 out. That is another. Yeah, that's an interesting question for this. We did not test the bb, 4 l. Impact. However, that is something that I personally am so second, and I
WH11NE- Sunrise: did a study, and we showed that everybody in the world was using. Okay, sure, you're using them corrections. You need to turn off because they double count major corrections that are in
WH11NE- Sunrise: you're assuming
WH11NE- Sunrise: when you're looking at this top volume effect, you're assuming standard. Yes, yes, so that's the width. There is 7 Gev. However, there is now a debate within the theory community of whether you should just use 2 times the top of mass with, because that is a more natural with. Now the issue is, that's not natural with no, no, that's not the natural with the oh, sorry
WH11NE- Sunrise: you're talking about 2 times the width of the top. Sorry 2 times the width of the cloud. That's a natural width of toponium. However, the issue is that toponium is not just the single resonance of the threshold region. Because you have such a large top width, right? You actually smear. There's multiple resonances that would appear right like Tremonia, etc, and because of that large width you actually get a continuum of torponium states. So there is some current debate within the theoretically, what is the actual proper width.
WH11NE- Sunrise: When you do like the non-relativistic Qcd greens function, you can fit like an approximate width. And that's where the 7 Gev comes from that we use. Other people have used the 2 times the top with. And then they get actually a different cross section. It's about 50% lower. Do we know that the top with.
WH11NE- Sunrise: as predicted by the standard model.
WH11NE- Sunrise: Yeah, what we say in general?
WH11NE- Sunrise: There is a measurement on that right of the direct comfort with measurement. No, no, no, no, I don't recall the precision off the top of my head. But yeah, I mean, it's it's a difficult measurement, for sure, because of your resolution. But no, it's not like 10 times like a 10% certainty. But I'd have to check. I do know we've done done this measurement, but the width is measured
WH11NE- Sunrise: things like 10% or less. Yeah.
WH11NE- Sunrise: But I'd have to check. We have measures. I know I've seen this, but at least either outlets or Cms.
WH11NE- Sunrise: Oh, okay, I can find it again. Yeah, yeah.
WH11NE- Sunrise: it wouldn't be very scientific. But like, if you take the like post fit of your data or of your toponi normalization parameter. And just like check, does it favor the right measurement? So I can show you that right? So we get a very small pull right here, but we but we had a large uncertainty associated with it. So
WH11NE- Sunrise: I mean, okay, we did flip the internally, we did flip it around, say, Okay, make this a searchable to ponium and fit the signal strength for tipoonium. It was not sensitive enough, and that's because our analysis was not, you know, designed to look forward to discover, and there was a follow up, and they, of course, now see, there is some pseudo scalar structure.
WH11NE- Sunrise: Well, you said this was using 2016 data. Where are there differences from between like 1718 data that you know? Stop you from doing multiple run to now. Absolutely not. That is something. I'm currently, you know, investigating as a we just knew that you only needed 2,016, and we were still in the process of analyzing 17. So we said, Hey, why.
WH11NE- Sunrise: why make it harder? Right? You can just go ahead and use it on 16 of this? Many. So.
WH11NE- Sunrise: But yeah, that's, I guess once we do for you, this will not be a procedure like, maybe, for how does that? Yeah.
WH11NE- Sunrise: maybe 1 1 more. That so is there any of the different facets that you talked about that entered in one of these like
WH11NE- Sunrise: strategy? You know future things about saying oh, if you do.
WH11NE- Sunrise: if you do, instead of the Fcc, you know ee, or whatever you want it to be at a certain
WH11NE- Sunrise: energy for these kind of measurements, for I don't know for the topoonium. Would it be already done by the time?
WH11NE- Sunrise: And it happens so for taponium especially. It's still an incredibly difficult measurement when you talk about with the Hadron Collider. Because, I mean, like, Okay, what do you want to see to say that this is definitively tap on it right? You want to see it also in other decay channels. But the the next highest decay Channel has top works is top works. Have this poor reconstruction resolution issue is 80 to Gamma Gamma
WH11NE- Sunrise: and that cross section. It's smaller than I think. It's like an order of magnitude or 2, so I
WH11NE- Sunrise: can't write the exact cross section off the top of my head. But I did estimate for 4, 1, 2. There's like 11 events. 11. So it's really really small cross section. However, maybe in the high Lumi, we could then see this right? That would be the 1st starting to say, Okay, there's actual temponium here for E, plus e minus. You can. You can see temporium absolutely right. And that's actually one of the best ways that you can get. A measurement on the top part mass
WH11NE- Sunrise: and the width is is scanning the the threshold region into plus and minus collider
WH11NE- Sunrise: in terms of these, like entanglement, or like the quantum information inspired measurements there has been looking into the e plus e minus. You really would like to have polarization. Then you get a little bit closer to like a aspect type experiment where you could actually like control the polarization. There's still lots of issues there, lots of loopholes, etc.
WH11NE- Sunrise: So I don't think we're really close to saying that we can actually do like a bell test or something like that. Yeah, I I think that's maybe
WH11NE- Sunrise: good place to start there. But yeah, there's it's there's still lots of ongoing discussion around this. Yeah.
WH11NE- Sunrise: any more questions.
WH11NE- Sunrise: Now, let's thank Aj again.