Frank Krauss: Thank you very much for the invitation I start sharing my screen and i'll try to figure out how to use it disappear, it was this one, let me go here okay so i'm going to talk a little bit about position simulations for the lsc.
Frank Krauss: please feel free to interrupt me at any moment, I mean you know it's i'm not bound to to go through the talk really so um so that'll be fine quick motivation and I think this is much current quarter Newcastle.
Frank Krauss: To date, apart from maybe, apart from the be anomaly.
Frank Krauss: there's no real smoking gun for new physics and especially in the high energy frontier that's it's really pretty but that's what what nature has designed to surface, so I think it's fair to say that simple discoveries out and, and so the name of the game now is.
Frank Krauss: To talk to try to push the standard model to its limits and and try to find subset of Asians now, as you know, statistical uncertainties in many cases, such a broad Cyril.
Frank Krauss: And that means that we can have a trade off between statistical and systematic uncertainties in such a way that in many cases the uncertainties are dominant are becoming dominant.
Frank Krauss: Which from a theory point of view, is a real shame, because some That means we have to work much, much harder now, needless to say.
Frank Krauss: It.
Frank Krauss: My my take is that.
Frank Krauss: It will become incredibly more complicated to to become much more precise and so at some point, I think we will have to have a discussion about about pain vs game.
Frank Krauss: So anyway, just to just to set the skeet to set the scene, if you want to be an event generator you pretty much divide the full event into different stages.
Frank Krauss: And you can try to start improving them one by one, so a lot of focus has been on what you would call this the signal event.
Frank Krauss: Which is where fixed order perturbation theory lives, and we have seen amazing progresses in the last I would say 1015 years with automation of an old calculations and first three breakthroughs in next next leading all the calculations.
Frank Krauss: However, you choose some time as some initial final state particles and then you start realizing that because you produce charges, they will start ready ah radiating and.
Frank Krauss: They will typically put shoes particle multiplicity is that make it impossible to use exact matrix elements, and that is where you start using something called the pattern showers, and that is yeah in a way it's an attempt at an American reformation of penetration theory.
Frank Krauss: At that point we would all be very happy, but but, unfortunately, life is a little bit more complicated protons are.
Frank Krauss: Extended objects, and that means there's any chance that you have more than one part on peer interacting with each other.
Frank Krauss: And that gives stress to something called the underlying event now, the problem is i'm not going to really, really discuss it in any way.
Frank Krauss: They don't have any proper first principles theory for the underlying event, and the reason for that simply put is that, in order to make our sequel event last part of shows that work we use something called factorization theorems and they kind of tell you that.
Frank Krauss: In order to extract one part one out of a proton you can use pdfs.
Frank Krauss: So you can factor is a cross section calculation into one part, that is, the PDF part and then everything is for the underlying event, where you have to extract more than one part on such factorization the rooms just do not exist, and that means what we do here is.
Frank Krauss: Is heavy duty modeling the the Porsche name, for that is fairly logical models and we're definitely logical because they've tried to describe this phenomenon.
Frank Krauss: But you have to understand I think it's fair to say that we are quite away from from proper theory.
Frank Krauss: In terms of you know factorization the rooms in perfect unity in the game repeats itself, then you start realizing the patterns you produced again we're going to use a logical models.
Frank Krauss: So what happens is that we run the pattern charlestown to really, really lost kids think of something like one GB or so.
Frank Krauss: And then we realized that the language of quarks and gluons is just not carrying water at all anymore, and you translate stuff into into first set of actions and many of these guys are they're not stable and you have to decay them.
Frank Krauss: Now this is yet another place of beautiful modeling because if you think about it, let me take the example of be have sean's for them, we can use effective theories.
Frank Krauss: Like heavy kwok effective theory and maybe some some tricks with co perturbation theory sort so there's games, we can play, however, when you look at the PDF to start realizing very quickly that you know, only about 50% of the decay.
Frank Krauss: Of the branching ratios of of the BC R amp D plus minus marathons and becomes much, much less for piece of S and the Lambda is apiece.
Frank Krauss: So, at some point we have to moderate stuff and one thing you will realize very quickly, even for the, for the simple most things.
Frank Krauss: Quite of the PG punching ratios don't don't add up to one, so you have to work a little bit there and at some point you just you know.
Frank Krauss: For some of the higher line resonances you just hope for the best so having said all that that, let us briefly take a look at where we are in terms of precision.
Frank Krauss: So.
Frank Krauss: Oh, that that has that has completely vanished that is really bad i'm sorry so, so I think the summary here is that.
Frank Krauss: That we had an amazing amazing pretty cool from about 1015 years ago, something that has been caught the end and all revolution, where we managed to automate next leading ordering QC D and subsequently in electronic corrections.
Frank Krauss: In the last five years.
Frank Krauss: The vs the theory Community push this a step further and there was some there was a beverage of the order of about 100 papers in the past five years, which presented restarts for practically every to to to process that is relevant biology physics and for the first two to three.
processes.
Frank Krauss: So where we at the moment is that our current accuracy standards is that we have.
Frank Krauss: And let me take as an example the absolute standard can look.
Frank Krauss: At fixed already have a first next to next to next to beating or the recycled 4 trillion production, which is, which is three loops.
Frank Krauss: We have next to next to leading order for vector for vector ozone plus jet and in fact the can we can match next to next to leading order for the inclusive hi Yun production with a part on shower and then we can play all possible games of multijet merging for higher jet much simplicities.
Frank Krauss: At next reading order now if you put this together, you start realizing that.
Frank Krauss: We have different places, have you have different regimes were different capacity effects dominate in a different way, so the law PT region, think of something of the order of up to say 1015 maybe 20 GB.
Frank Krauss: is pretty much dominated by our understanding of how the pattern child works and we learned a lot about this in the last two three years about what's about some some inconsistencies by comparing with the program of analytical resignation.
Frank Krauss: The high PT region is dominated by multijet apologies, where we typically have next week in order precision at hand, and that means our typical accuracy is of the order of 10 maybe 20 30%.
Frank Krauss: We can further improve the accuracy in the rate and sometimes in the shapes also through some next to next to leading auto matching.
Frank Krauss: So I think it's fair to say that, in terms of QC defect our understanding of of collagen production is set the level of.
Frank Krauss: 10% 15% roughly across cross face space, which is pretty awesome and I think 10 years ago no one thought that that would be able to push it that that form.
Frank Krauss: Now, if you want to go below them the magical 10% and go for you present level position or around.
Frank Krauss: Then I think you have to to to add electronic corrections and again they come into interesting places at large scale so think of hi Mr slept on peers.
Frank Krauss: or large PT vector posts on production, you would have to include directv corrections were at large scale large scale something like a TV they can't fall around about 10%.
Frank Krauss: So without them 10% without electricity corrections 10% at the large scales, is in a way that's that's the official, if you will not will not manage to get food with the audit.
Frank Krauss: and, similarly, if you want to have vegetables online shapes and maybe to precision measurements of the w mass even have to discuss Judy final stage radiation plus electronic corrections in the in the vector posts online shapes to go to go better than the percent level position.
Frank Krauss: So, so that is pretty much where we are now, if you want, if you think about this in the context of simulations you have to ask yourself how you get these beautiful calculations into your potential Monte Carlo.
Frank Krauss: And the tricky part here is the following, if you do higher order calculations and next next leading order annexed next living oversee.
Frank Krauss: You used to not only have the loop amplitude but you also have amplitude with extra emissions.
Frank Krauss: And in fact you need port in order to make sure that infrared divergences cancer, which is, which is fantastic.
Frank Krauss: But once you start, including these readmission corrections, you also have to realize that the part on short types on emissions and there's some type of accounting.
Frank Krauss: So you have to make sure that we set it to not top account emissions between the fixed order and their estimation.
Frank Krauss: And at next week in order to have been to schemes for for nearly 20 years and they have been deployed, I think, from the get go at the MC MC it and it went ahead.
Frank Krauss: And the next next reading order test again to schemes mindo at and tulips now I think mindo is is pretty much something that is standard standard that is deployed standard.
Frank Krauss: And onwards, I think, has not really been deployed so far for the nfc the caveat is that both were crossing that's only so only if you're producing that finals color singlet final states like they're young so think vegetables on maybe vegetables on past maybe expose on.
Frank Krauss: And so the reason for that is the following.
Frank Krauss: In mindo you pretty much so Min next next leap mindo next next reading order you use the next reading order for heck for the production of a single plus a jet.
Frank Krauss: And then you, and then you let you allow the PT of the single system will allow you to go to zero, which means that your jet PT also goes to zero so so you discuss patterns, with a PT down to have the order of the gv now The problem here is, as you know that the abduction structures.
Frank Krauss: They exist at leading order and they continue to exist at next moving or if there's extra jet goes to to various more transfers from enter.
Frank Krauss: And to capture these the divergences by rebating your by rebating your configurations with analytics would occur form factors which exists at second order is so the same logarithmic structures that look like logarithm of PT of the singlet.
Frank Krauss: subtracted, so to say compensates for analytics would occur form factors now unfortunately we know these analytics pseudo code form factors only for single production at second audience is.
Frank Krauss: So so so systematically Min law is constrained at the moment.
Frank Krauss: By our limited knowledge of analytics to the core form factors which are part of the of the scheme in and tulips.
Frank Krauss: The game is slightly different because the pattern short terms are subtracted from at fixed order from the from the signal plus jet contributions in actually quite a nifty way.
Frank Krauss: But the analytic control over the part on show it expires, when you go below beyond the signal production because your color configurations become more and more complicated.
Frank Krauss: So both schemes available for for simple process only and, to some degree the common limitation is that our part on chairs are limited in the accuracy to first order in our face, so what so we have to.
Frank Krauss: Simply put, the only controlled in the pattern child the emission of the first part on.
Frank Krauss: Night next next meeting audio can emit up to two parts, and so we have a mismatch there, and as long as part on showers are not accurate in in capturing all logarithms and the full structure of to emissions, this is the best we can do.
Frank Krauss: So let me give you an example of what it actually translates to in terms of accuracy and I think that's quite instructive.
Frank Krauss: In the Left panel, you see a typical.
Frank Krauss: menlo example.
Frank Krauss: In in in cream, you see the fixed fixed order cluster estimation T y and anello.
Frank Krauss: inclusive you see the set plus jet mindo at next leading order and enrich you see what happens when you then start adding the next next to leading all the parts on shore in the middle scheme and you see that.
Frank Krauss: This next next meeting or a minimal scheme increase extremely well with the with the with the analytical side and the cruces we achieve there are at the level of a few percent in the inclusive cross section, with respect to the rapidity.
Frank Krauss: It becomes a little bit less coat when you go for for the PT spectrum, and for that I I just use the tulips the restarts are very, very similar in terms of accuracy for for.
Frank Krauss: So on the right hand side you'll see on tulips and there we have a comparison with X with experimental data from cms actually.
Frank Krauss: And that's the PT spectrum office that goes on.
Frank Krauss: In in a certain.
Frank Krauss: With with a with a typical construction from trust electrons etc.
Frank Krauss: And you see the the theoretical accuracy is at the few percent level, apart from the first in the let me call it the COPD Ben which reaches up to about two GB.
Frank Krauss: And you'll see that the agreement with data is pretty good so to to quite successful schemes, they have been around for seven eight years I think mindo is standard we deploy it whenever people do young type of policies.
Frank Krauss: Now the other thing that that is a little bit orthogonal to that instead of doing a fixed auto matching by trying to put as many ends, as you can into your calculation.
Frank Krauss: You can see well actually it's much, much easier for us to automate at a given position to have more and more extra emissions, so if you if you think about it.
Frank Krauss: We can easily calculate the production of set us on also plus up to six seven jets so it hurts a little bit in terms of cpu consumption but by and large it's it's straightforward and automated.
Frank Krauss: So how about we just combine all the different jet multiplicity is in one one sample and this idea has been around for nearly 20 years, I just want to to to advertise it a little bit.
Frank Krauss: Because in terms of of say description of shapes.
Frank Krauss: it's quite apparent that extra emissions are much more important than extra loops because extra emissions may open certain face base regions and as an example, look at look at the at this comparison here, this is our class because i'm democratic so actually cms and atlas data.
Frank Krauss: And if you look at the PT spectrum of dive photons at about 50 GB or So you see this little bump and and this little knee it's.
Frank Krauss: This little unique comes from the fact that you apply isolation cuts on the two photons but at some point the two photons can become, let me call it nearly parallel and recall against next project.
Frank Krauss: So the combined transits momentum of the two photon sent is larger than the than the say individual.
Frank Krauss: transistor momentum now if you come if you compare this and I want to stress this completely unfair comparison and it's it's it's it's really just in this photo illustration purposes.
Frank Krauss: If you would run a very naive pothier part on shore Monte Carlo with that starts from kwok anti quark and crew crew to two photons and just stress it with a part on shower.
Frank Krauss: You cannot see this me because the pattern is not capable of reproducing this kinematics configurations, we have the extra emissions a harder than the individual photon transitional mentor.
Frank Krauss: However, if you start using some way to jet merging of course it fixed order when you when you add fixed order matrix elements for for these kind of configurations you completely map them out.
Frank Krauss: And that is kind of cool because if you compare the left hand side and and the data over overshadow, which is the motor check merging it looks really, really good.
Frank Krauss: If, on the right hand side you compare with some analytic calculations, you see that even the nmc calculations struggling a little bit, and that is because the interplay of Reformation and.
Frank Krauss: An extra missions it kind of saturates, a little bit too fast and that's why they don't get the that that's either don't get the knee.
Frank Krauss: quite correct, which is you know kind of interesting so that led us to believe that we should try to do this multijet merging at next leading order.
Frank Krauss: And that's again a technology that is that it at the moment, I think, is the is the standard technology for high multiplicity final states.
Frank Krauss: At the Agency so simple, to put it simple sometimes more lex wins over more loose So how do we get more lex into the into the calculation and the ideas that you build towers of matrix elements with increasing jack multiplicity and try to avoid or remove overlap and double counting.
Frank Krauss: By also trying to maintain the respect their respective accuracies of at next leading or in the matrix element and leading lock in the pattern shower so to effectively do is that you will take a bunch of mcs and a lot of simulations and put them on top of each other.
Frank Krauss: Now there's different implementations of the same idea, they are relative accuracy is not always clear and not everyone who published try to actually investigate what the parametric accuracy is.
Frank Krauss: Now so so, how does this work and, yes, yes, a little example, if you look at the transistor mental of the higgs boson.
Frank Krauss: As for instance done by by mcs and hello, you get a beautiful PT spectrum and, if you would look very, very closely, you would see a little bit of a offered this content, where.
Frank Krauss: it's a smeared out is continuity at the at the mass of the scores on, and the reason for that is that below the mass of the higgs boson at mcs no you choose your next meeting, or the matrix elements with a key factor of two.
Frank Krauss: round about and below and above this, this hicks mass transit mental spectrum would be given by leading order matrix element.
Frank Krauss: Which doesn't have this key factor so so that's why this is what it looks like now what you would do in if you wanted to stack it, you would restrict the first mission in such a way.
Frank Krauss: That.
Frank Krauss: That you that you introduce the cut and to say, well, we don't allow any emissions to be above this cut, which I think here we have at 20 GB.
Frank Krauss: And then you take the next leading hicks plus jet calculation, with the JET has to have a party larger than 20 GB.
Frank Krauss: And you start feeling and you start adding it up and because the to face basis artists joined I eat the first emission is below or above the culture could just add them in an incoherence.
Frank Krauss: Now you can also meet with this thing again and, at the to chat next reading order and you could lead to it and get a three jet and so on and so forth until you add it all up and you get this spectrum and and that that means that for.
Frank Krauss: For for a transistor momentum of the higgs boson Archer then hundred or 200 gv you start seeing contributions from different multiple technologies and at some point, you see.
Frank Krauss: How the higher multiplicity start taking over the law of my felicity, and that is also, I think, to be expected and and I think it completely fits my intuition, so we check that.
Frank Krauss: For instance, for that plus jets, which is a beautiful little laboratory again with with atlas data and and to see that.
Frank Krauss: You see a comparison of number of chats and the the overall hotness kill hd.
Frank Krauss: In in that pool you see a fixed order calculation increasing you see this next reading order merging in yellow you see leading order merging.
Frank Krauss: In pink you see leading all the merchant by matt graph and in purple you see your next meeting, or the merchant again America and you see by fine large if you go from leading to next leading order you start.
Frank Krauss: You start describing data much, much better and typically at a level of say 10 to 20% again this is, you know, this is where we are that's that's the 10% of accuracy, I was, I was trying to advertise the beginning.
Frank Krauss: Now he could also start adding loop and choose those is, for instance for WW production.
Frank Krauss: And that just add this because.
Frank Krauss: I think when you start looking for more and more than me call it complicated processes at some point we will start, we will start looking into set Karma associated production and check what if he can, if you can see the hicks graduation to set come and similar.
Frank Krauss: So for that we have to be able to add the loop insurance policies and of course we can empty it and annoyed again with a very similar in a very similar logic.
Frank Krauss: So quite a thought thought I think the summary, for that is that at for QA QC deep for simple processes.
Frank Krauss: That are very inclusive so inclusive similar production we have next next meeting capacity of hand and for more complicated processes, either because they lose interest or because they have larger multiplicity you have to see the next leading order.
Frank Krauss: Now.
Frank Krauss: I also I also hinted at the need to include electronic corrections.
Frank Krauss: That that we have to include because at large scale, the factors of the order of 10% So yes, if you want to go better, you have to include that.
Frank Krauss: However, the problem is that they are really, really painful to calculate and that's just the nature of electronic processes which have many more mass kids which make a lot of our of our techniques much more cumbersome.
Frank Krauss: So just to give you an example.
Frank Krauss: On the right hand side you see the ratio of set and offset production over gamma production independence of on the PT have the balls on and you see without without electricity corrections to describe data or not.
Frank Krauss: So so so The difference is completely to to the electric charge of the samples, and you can imagine that 800 GDP team.
Frank Krauss: The mass of the of the set versus the mass of the camera is a small effect so it it comes cut tragically so pretty much irrelevant, so you have to include the electoral week.
Frank Krauss: You have to include the electoral week corrections.
Frank Krauss: So here's another example for this, and that is the w production in conjunction with jets and to see that and that's that's pretty much the theory study.
Frank Krauss: enlighten you see what we do at leading autocue city and increasing you see what we do at next meeting audience use it in, you see, they kind of agree in terms of shape with each other, and the answer depends just vanish.
Frank Krauss: and
Frank Krauss: Then you see in red what happens when you start adding electricity corrections and what is kind of equally is that.
Frank Krauss: The transfers momentum distribution of the of the of the Web was on.
Frank Krauss: takes takes quite a hit of the order of nearly 40% or so at one TV.
Frank Krauss: But you don't see the same for the for the first gen, and the reason is that.
Frank Krauss: Your your old system.
Frank Krauss: becomes much you have more and more jets so so completely change the overall record structure, and that is kind of an interesting one, and it hints at.
Frank Krauss: At.
Frank Krauss: At the fact that if you start having more and more jets you start looking for electricity corrections it clue on versus cooperates with the quran jets don't have an electric charge and therefore.
Frank Krauss: I wouldn't say go free, but the the impact is a little bit more indirect and for walks which cover directly to the electronic Muslims.
Frank Krauss: So, and you can imagine that, if you would look for new physics say into pity spectrum of w balls ons.
Frank Krauss: And she would see a 40% increase at one TV with respect to your beautiful next reading or accusatory sample.
Frank Krauss: And in fact that would be the same 40% with respect to your next the next leading autocue city sample you'd be tempted to claim that you found some indication for new physics.
Frank Krauss: But, in fact, the only thing you found out is that you forgot about it actually corrections which will be a little bit embarrassing, I guess, so we better take this into account.
Frank Krauss: So we can we can play a similar game again how to include the electronic predictions, and this is kind of a kind of a fun measurement people looked for the data are between the moon at the hardest jet.
Frank Krauss: And if you look in a in a large PT sound pencil where the chat has 500 gv PT and you asked for central central chat at leading order.
Frank Krauss: The moon is the who was on this massively boosted, so the moon goes pretty much in parallel to the w balls on.
Frank Krauss: The data high between the moon, and the chances of the order of pipe, that is what you get at leading order.
Frank Krauss: Now, if you start adding next reading order corrections, then you start realizing that you can also have a second jet so so This correlation is softened a little bit.
Frank Krauss: And that is the green curve now you could start adding electronic corrections and it changes the picture that will be introducing the peak and you know getting the second peak that comes from the second chance, a little bit higher.
Frank Krauss: We can also add the impact of photon pdfs which actually does play a role, address a few large data on.
Frank Krauss: And now we say well actually.
Frank Krauss: Let us restrict the game to have exactly one jet us for know second jet larger than had to gv and you'll see the correlation between the the JET and the moon is pretty much restored.
Frank Krauss: But now we can start adding the w plus to chat sample at next to leading order repeat the full game again.
Frank Krauss: And again it's to two different samples, and you can edit all.
Frank Krauss: And, and that that works actually pretty well and here's here's the here's what comes out of often analysis and you're seeing cream it's leading order action and to the best of my understanding, no electricity corrections in it.
Frank Krauss: In in orange it's next to next leading audit use the sample.
Frank Krauss: With some electronic corrections and yeah I mean, I think you see the very moment you do it right you you you you describe data, which I think is quite Nice.
Frank Krauss: So, so I think in summary it's fair to say that, with a with a few tricks and and, if you will have to discuss them in more detail, we can also start adding.
Frank Krauss: Electricity corrections into the mix at next to leading order, so we have pretty much poised to go better than the 10% but the but the big problem here is that and I come back to that the the have an issue with a part on showering.
Frank Krauss: It prevents us from taking more complicated of describing more complicated process, he said next next leading autocue city, and we have to do this mindo on tulips technology, so it would be great if you could have.
Frank Krauss: Better part on showers so so we have to understand them a little bit better so they are it's important to say that they approximations to the path to the to the emission pattern.
Frank Krauss: And they have a couple of approximations in it the first approximation, is that you forget about SAP leading colors, and that is typically.
Frank Krauss: an effect that is less than 10%.
Frank Krauss: Now, if you speaking it's 10% one over MC squared so nine, but then typically The sub leading colors are also logarithmically suppressed so it's it's typically in effects more than 10%.
Frank Krauss: They exist only at leading logarithmic accuracy and they also have some intrinsic spin efforts in which plays a role.
Frank Krauss: And we cannot try to compare their parametric juicy by comparing them with analytic calculations and other calculations, yes, the pseudo code form factors with coefficients A and B.
Frank Krauss: And these coefficients in br typically expansion autism is so for for simple processes and.
Frank Krauss: In particular, for for similar production.
Frank Krauss: For single production as no one up to 30 ordering QC and B is not up to second ordering QC and that actually enables us to do this beautiful minerals scheme.
Frank Krauss: Now, in part and Charles you typically only have terms that that correspond to a one and a two So the first one is in a in the first order in the only.
Frank Krauss: So you see if you wanted to push the accuracy of pattern showers to something that is similar to what we have analytically who'd have to add one extra mission into the game.
Frank Krauss: Now, how do we, how do we do that.
Frank Krauss: So, so let me, let me just say that now if we speaking the driver of our part on charts are splitting kernels and we typically only use the CEO of the oddest splitting current which is order is.
Frank Krauss: So if you wanted to go to higher precision would have to include the order is corrections.
Frank Krauss: And, in fact, if you want, if you would only aim to reproduce the club evolution of next leading order would include the nfl splitting kernels.
Frank Krauss: And if you look at these P one terms they come in three categories there's something that is called the cast and that's a universal soft enhanced Gretchen and that has been.
Frank Krauss: In the original part on Charles for 30 years now, because it's completely trivial then there's specific non trivial corrections to one to two processes and you also get new flavor structures.
Frank Krauss: pretty much because.
Frank Krauss: You you saw typically when you think about the spitting current it's they are qua qua qua clue no clue and going to glue glue or clue on going to quote antique walk.
Frank Krauss: And if you go one or the higher, you can have a client that emits a clue on in the clue and splits into another call, and that is.
Frank Krauss: innovating new process category that you have to implement and i'm going to show you some results, but I want to, I want to stress that they have to be taken with a grain of salt because there's.
Frank Krauss: Some issues with locker purity that still need to be resolved so.
Frank Krauss: If you include these higher order splitting cards in a very, very nice if they have estimating scale uncertainties your choose to scale uncertainties and what you see here is the pity distribution of opposite poles on now.
Frank Krauss: it's, this is a this is most likely a too naive way to estimate the scale uncertainty.
Frank Krauss: Because when you when you look a little bit more closer, especially into into soft emissions only you start realizing that beyond if you go beyond just adding higher order splitting kernels there's some extra terms that show up.
Frank Krauss: That reintroduce quite a sizeable scale answer to such that the reductions kill and certainly from true to read that that you see here.
Frank Krauss: is actually too optimistic and it's not a reduction by a factor of 10 but more like a reduction by a factor of two that you are thinking, and this is, this is what you see here if you start into, including the leading color differential two loops of corrections which is.
Frank Krauss: Which is pretty tricky because it takes into account non trivial color correlations.
Frank Krauss: You start realizing that there is one one term that is a little bit upsetting and that's a term of a logarithm of this year, that is.
Frank Krauss: slightly, but that that is a little bit uncompensated.
Frank Krauss: So anyway, if you include these to include these terms, you can also start discussing the.
Frank Krauss: The first, the first one over and see corrections, so you start going beyond the limit of leading color you can also incorporate spin correlations and and that actually does have an impact not only on the accuracy of the part of shower but also on the shape and if you compare.
Frank Krauss: If you only go for for higher order splitting kernels in this co linear approximation you don't really change the central value of your part and showering going from leading order to next leading order, whereas when you when you include.
Frank Krauss: When you include the.
Frank Krauss: The tulip soft.
Frank Krauss: You have the feeling that there's a little bit of a shape change now, and that is kind of interesting.
Frank Krauss: So i'm not going to bore you a lot more with with how the rebating actually works and how the one over MC effects actually works, but I want to.
Frank Krauss: I want to come back to to the question of the former position of the part on Charles which at the moment, in fact, is where I think the discussion in the Community is.
Frank Krauss: And I think it's clear from from from the past 40 minutes or so, if you want to push beyond the 10% you have to discuss pattern showers and we have to discuss their former position.
Frank Krauss: For us, this will be the only way to systematically include.
Frank Krauss: Next to next to leading autocue city gretchen's that we that we actually have no attempt analytically for for five years, so if you want to go beyond the 10% accuracy, you have to discuss the formula accuracy of the pattern showers non English speaking.
Frank Krauss: For simple observer birds.
Frank Krauss: There it has it is known that the pattern shower if you formulate in a suit reform is next leading lock accurate for for a set of simple observers, provided that you remove the stuffed up accounting and that you include this.
Frank Krauss: total cost analysis dimension which is this university itself term.
Frank Krauss: Now what this means numerically it's not entirely clear for a number of reasons and.
Frank Krauss: The, let me just highlight to when you when you start doing your analytic when you start doing your analytic transformation.
Frank Krauss: You typically do not conserve the full for momentum, you only conserve your momentum in transit or longitudinal space dependent on what reservations Kim use the part on shark typically typically conserves the the total for momentum so so we have.
Frank Krauss: We have to to discuss logarithmic accuracy in the presence of momentum conservation, which, in terms of logarithmic language is is a is a logarithmic contribution at even higher orders, but, of course, numerically it actually plays a role, because we are not at infinite energies.
Frank Krauss: Also, the part on show is a tree and the next little block approximations break this unitary unit charity so so so we have to discuss how.
Frank Krauss: What the what the numerical impact of these physical conservations, namely momentum and probability conservation actually tells us about.
Frank Krauss: About algorithmic accuracy and that is, I think a discussion that was kicked off round about four years ago, but it kind of petered out a little bit, I have a feeling, this is something we may have to go back to them.
Frank Krauss: We also learned in the last two three years that they are issues with the second emission in modern pattern showers.
Frank Krauss: has been a known problem, but it has been solved actually again 2030 years ago, but for modern part of show us some of this problem has resurfaced and he started realizing that.
Frank Krauss: The logarithmic accuracy does not only depend on how you play with is soft up accounting and the total cost of animals dimensions, but you have to be also very careful about what your evolution skin, the potential is and how you and how you build the kinematics.
Frank Krauss: off your part on shower and that goes back to this for momentum conservation question you have to make sure in technical terms, that you do not upset.
Frank Krauss: The angular correlations between your between your heart apart on send humans after patterns, so the only way forward to to deal with this is to design a new Monte Carlo.
Frank Krauss: part and show that reproduces next to leading lock exactly loss emerging and matching and then allows folks including higher order splitting kernels, and that is pretty much where we are at the moment, now.
Frank Krauss: I would like to to to flip for a moment to to some persistent problems that I find interesting to discuss because.
Frank Krauss: Irrespective of what we do at fixed or then with a partner and show us, there are a couple of issues that I think there'll be extremely hard to solve, so the most the most simple one.
Frank Krauss: I think, to solve is probably what you do with glue on splitting into kwok into into heavy kwok antique walks think of clones splitting into bees.
Frank Krauss: They have been they have been analysis by both cms and atlas and the upshot is that we do not fully control the crew and splitting to quote anti quark and that leads to deviations.
Frank Krauss: Between data and and simulation of the order of up to 50%.
Frank Krauss: So we have a few very old pointers coming from that, looking at the clue to pb and clue to charm charm rate.
Frank Krauss: And we have as as I hinted at some more modern analysis from atlas and cms.
Frank Krauss: But it's very clear, we still have to fix it and there's a couple of questions related to that which have to do with what kind of spitting current or do we have to use an equal to hire artist.
Frank Krauss: How to leave you with a quote masters really what's key or do we choose five is so lots of questions and just to show you the latest atlas measurement.
Frank Krauss: So this is, this is a measurement where you look into the production of to be marathons and to ask one PMs on going to jail sigh and the other one going to move on and to use the shape, size of the moon perform the job site or the individual me on as proxies for the to be marathons.
Frank Krauss: And when you look at it, you see different options, and especially in the right between matt craft sharper Pantheon herbenick and ngc dependent on what potential option to use to get variety different results, then you go into the shower each night data are going to zero.
Frank Krauss: So that is a little bit of a of a problem, and I think this is something we need to fix.
Frank Krauss: So.
Frank Krauss: There is another.
Frank Krauss: related problem, and that is not massive clocks in the finest dates, but massive clocks in the initial states and the reason he has the following, if you look at your pdfs and you look at the scale of the PDF dropping below the the quote mass threshold.
Frank Krauss: there's no PDF support in our part and shower scheme, the clock, then stop showering now because we do everything with silica form factors.
Frank Krauss: It means that there is a finite probability for quarks for heavy quarks reaching this threshold, so if you think about TV production.
Frank Krauss: There are a couple of their few percent of crayons being produced by the by initial states and these 2% of the boss have a final chance that one or both of these bees.
Frank Krauss: have not been transformed international crew and so you have so you arrive at low scale with to incoming with to incoming big box.
Frank Krauss: And to tool to solve this office to possible solutions are very naive and you say, well, if I arrive at the clocks every deal with them in a in a completely ad hoc way for the beam remnants.
Frank Krauss: A slightly better way is to enforce enforce the splitting of the of the initial Beak walk into an initial clue on.
Frank Krauss: Around mq script and then continue with the part on showing of the gloom.
Frank Krauss: I to the best of my understanding, no one has really checked the impact of these choices on observance, like, for instance.
Frank Krauss: The ratio of the PT of the w over the beauty of the set posts on which is instrumental for the measuring of the w Mars, so there are a couple of issues related to massive quarks that actually may have direct impact on the experimental program at the nfc now.
Frank Krauss: Changing here a little bit, let me just let me just point out that.
Frank Krauss: When we do our venue to Monte Carlos we always assume that happen decision is universal, and that means we tune everything to lab data.
Frank Krauss: And we hope that we can just put it directly toward the everything else, and in particular to the nfc now when you look at when you look at it and you compare.
Frank Krauss: Alice data with with different Monte Carlos you start realizing that.
Frank Krauss: you're you're naive you're naive neptune's would assume that the ratio of use of the production of crayons lumped house.
Frank Krauss: cascades and AMI gas.
Frank Krauss: Is fledge with respect to pions because the strange and suppression is just a parameter, but what you see is that if you increase the multiplicity in the chatroom multiplicity in your event.
Frank Krauss: Or, in that case, the number of charged particles in the event, if you increase this multiplicity.
Frank Krauss: Your years of chaos lumps etc it's not completely flat, but it it actually increases a little bit, and that is something that.
Frank Krauss: That we don't see in our standard Monte Carlos.
Frank Krauss: So.
Frank Krauss: it's it's kind of an interesting one, it looks it looks and feels like something that you would.
Frank Krauss: That you would call them Su three restoration and that needs to be investigated now, I have a couple of illustrative plots but i'm not going to bore you with them because they're they're really hard to read.
Frank Krauss: toxin and one of his students made quite an quite an extensive study of what you can do in order to get your attributes back, and I would like to refer you to the paper there.
Frank Krauss: And that brings me to my summary so.
Frank Krauss: I cannot but but stress that our program of precision calculations of higher order capacity has been extremely successful So if you look at it.
Frank Krauss: For for energy calculations and you look at the number of final state particles on the X axis and the number of loops on the on the y axis, to see that we have.
Frank Krauss: Leading order to to six process completely under control, and you can actually quarter two to eight it's it's only a question of efficient CP of efficient algorithms and cpu power but.
Frank Krauss: it's it may be practically limited but it's it's.
Frank Krauss: But I think there is no limitation in principle.
Frank Krauss: The same thing is actually true for the next reading all the calculations again completely completely.
Frank Krauss: automated.
Frank Krauss: You can go up to two to four process without really batting an eyelid it becomes a little bit more painful than.
Frank Krauss: But again, this is, this is a practical limitation that has to do with efficient algorithms and our cpu power, but not with.
Frank Krauss: With the solution in principle.
Frank Krauss: For next next leading order you have to to to proceed, I think, completely under control and we start looking into the first two to three processes and we have one was actually a three.
Frank Krauss: So.
Frank Krauss: The wire, we have this next next meeting or acuity calculations attend for to to proceed for to troopers they're not yet fully available in in simulations and only a very small subset is available.
Frank Krauss: So this is necessary, this becomes necessary, then we want to push our Jersey limit to better than 10% you also have to think about how we combine our higher order capacity and higher or electronic corrections.
Frank Krauss: doing a mix to look juicy the electronic calculation.
Frank Krauss: Still, is quite quite a beast, so we will have to think about how we, at the end or multiply these corrections, and this is something that people started looking at.
Frank Krauss: And of course you can always continue to consolidate what we have at the moment, now for for upcoming the for the upcoming he runs I think it's I think before before 2025 this would see.
Frank Krauss: Next next meeting or at uc T plus and electroweak available for all to to to standard model processes, I think that is what we will have we will also have the first two to three processes, a total badass gct.
Frank Krauss: People are working at getting a partner in short order of esquire that that would get the logarithmic accuracy sorted and again.
Frank Krauss: Looking at the Community lots of people working at it, I have the feeling, we will be there, so my My suspicion is that.
Frank Krauss: In five years from now, we can start discussing the 1% accuracy for the couple of inclusive opposition observable it's like inclusive cross sections PT spectrum of the w setting so there will be a limited set of observance, we, I think we can discuss.
Frank Krauss: Precision at the 1% order, and I think we'll be able to fix this heavy flavor issue and in Thailand initial state.
Frank Krauss: I think what we were not really get under control in in five years is things to do with.
Frank Krauss: Let me call it complex behavior in pattern ization or the underlying event and.
Frank Krauss: Now.
Frank Krauss: This sounds overly optimistic and it completely does not reflect my personality, because i'm a grumpy germ so let me put some.
Frank Krauss: Let me put some caveats and the first thing that I think it's important to realize, is that we have massive efficiency issue, so why we have imprints where we have solutions in principle in practice.
Frank Krauss: It will still be hard to complete the utilize them because they're not efficient enough so you have to devise schemes.
Frank Krauss: To make our code smarter and that is going to be a big problem, because a lot of our monte-carlo codes date back to a time when memory was cheap and cpu was expensive and.
Frank Krauss: hardware has changed at the codes happened, so I think we will see that we have to rewrite.
Frank Krauss: significant parts of codes and.
Frank Krauss: That is going to be that is going to be a massive problem, and that is a place where the reason the activity of trying to get research software engineers into the game is actually quite important.
Frank Krauss: There is also.
Frank Krauss: A question in how far there are limits to our to our target of precision fulcrum.
Frank Krauss: So let me, let me try, let me try to angles, for that one angle is that it's pretty clear that we have our factorization theorem which pretty much tells us that.
Frank Krauss: We do an expansion in order to have not only in order, so it is, but also an artist of typical have sonics kids.
Frank Krauss: With a large scale of the process, so if you think of trillion production which lives at about 100 GB and then you think about the typical size of of have tonics kids are to gv or non tech city, you see that linearly, this is a 1% effect.
Frank Krauss: Now it's pretty it's kind of common law that these.
Frank Krauss: Higher twist effects commit quadratic order so it's not a percent or 2% of a percentage 10 to the minus 10 to the minus four effect, but that is common law and it's not really proven and certainly not proven for generic processes, so there is a question in how far.
Frank Krauss: Are factorization theorems that also imply an ordering in in hired an expansion and twist will actually implicitly pause and limit and to the best of my knowledge, at the moment there's really no one would look into that in any detail.
Frank Krauss: You can you can also ask yourself how.
Frank Krauss: How to you.
Frank Krauss: How does your calculation improve when you go from next to emptiness one N minus one leading order order to one or the higher and.
Frank Krauss: interesting question is what the improvement actually is so it's clear when you go from reading order to next reading order the improvement is really, really good.
Frank Krauss: Because at healing or you have practice, you can pretty much achieve any research, you want to, and if you go from leading our next meeting or.
Frank Krauss: Your scale uncertainty become become a sect except me fully accessible for the first time, but, of course, at some point the relative game they kind of become become too small to be to be relevant and the interesting question is when this is the case.
Frank Krauss: know that the last thing I want to say is that.
Frank Krauss: For for many observers soft on on performative effects actualization underlying event will become the biggest uncertainty.
Frank Krauss: And the real shame, he has that practically nobody works on it so, so I think it's fair to say that we will push our prerogative calculation Program.
Frank Krauss: Easy one order higher in the next five years, but I think beyond that we will have to discuss parts of the simulation that at the moment no one really is concerned about.
Frank Krauss: and
Frank Krauss: yeah I think that is where we are with it.
Frank Krauss: Thank you for listening.
Ivana Hristova: Thank you very much, from for this nice talk, let me stop the recording.