Rebeca Gonzalez Suarez: Okay.
Rebeca Gonzalez Suarez: okay, normally do. I don't also sure if anybody looks at it. But I think it can be used.
Juliette Alimena: Okay, great.
Juliette Alimena: So yeah, thanks everyone for for joining so today, we have 2 contributions and and also some important news. So maybe Giacomo can get started with the the news.
Giacomo Polesello: Okay, let me see, because and you see to them I'm trying to do it.
Giacomo Polesello: The share. No, the share. It's 1 of the days that the share doesn't give me the.
Giacomo Polesello: the, the, the, the window, the
Giacomo Polesello: the Pdf window. Okay, so I'll go for the complete from the complete thing.
Giacomo Polesello: And
Giacomo Polesello: So I you see the the slides correctly.
Juliette Alimena: Yes.
Giacomo Polesello: Because I lose the when I open it I lost the view, and so there isn't a
Giacomo Polesello: apart the news for having had that coming now from from A from the big meeting 2 weeks ago, and during this meeting we had a discussion about about the the issue of normalization which is necessary in order to be able to converge to the
Giacomo Polesello: the result, for the Feasibility report and the recommendation for normalization were sent us by by Patrice and company, and they are on the, on the, on this link which which you can, which you can click. And and there there is a
Giacomo Polesello: there is the list of luminosities which we one is supposed to use. So we are having 2, 2, or 5 inverse autobahn at Pole, corresponding to 6, 10 to the 12th
Giacomo Polesello: to 6, th and to the 12.th Can I get this thing out of the way? Probably not.
Giacomo Polesello: And for 6 and 10 to the 12 Z. Is then, and 19.2 inverse at WW. 10.8 inverse at the Z. And point 4 at at the Tt. Bar.
Giacomo Polesello: The for the high energy runs and given a process with cross-section. Sigma, that's trivial. You you are using the l luminosity. The numbers say numbers. Here the sigma of your process you get a number of events. Now it's a bit more tricky in that Z pole, because in in, as you see here, the Z pole run doesn't have
Giacomo Polesello: a single energy. But we are taking data. We'll be taking data for 14 versatoman at 87.9 Jaf
Giacomo Polesello: for 40 inversatom and 94.3 Jav. And at 125 inversatom and 91.2 Jav. So these differences seem to be small, but we are in in energy, but the point. We are around a very peak with the width of 2 Gev. Which is the peak of the Z,
Giacomo Polesello: which means that the the equal cross sections for for production of these in these, at the 2 satellite luminosity are different. So since we are going to take a data with, since our Monte Carlo will be with a single energy. 91.2 we need to. We need to come up with a
Giacomo Polesello: and prescription with a practical prescription in order to to be able to.
Giacomo Polesello: To. To say that what we are doing is indeed is in corresponds, indeed to the Z. 4 run of the Fcc.
Giacomo Polesello: So the practical recommendation are that for signals from Zdks. So you are looking for a
Giacomo Polesello: rare decay of disease, one and just normalized to 6 to 10, to the
Giacomo Polesello: to the 12 Z. So the number of events we have to assume is 6 10 to the 12, th multiplied by the orange refraction of the Z into the signal
Giacomo Polesello: for resonance backgrounds. Essentially the artificial backgrounds where you have a day, your background is a Z to EZ. 2 or whatever again the same. So for each sample of Z to something, the number of events is 6 to 10 to the 12, th for the bunch infractions
Giacomo Polesello: to something, whereas if you have 4 fermion backgrounds, for instance, these 4, these backgrounds are not resonant, which means that the cross section at 88, 91 and 94 drive will be approximately the same.
Giacomo Polesello: We did
Giacomo Polesello: some tens of percent. So then the the normalization will be done by 2 or 5, so that the total nominal luminosity multiplied by the cross section in autobahn for the Sigma for 4.
Giacomo Polesello: That this is, I think, is a kind of uncontroversial.
Giacomo Polesello: What's more complex is, if you don't. If for some reason in your analysis, you don't have these branch infractions that to signal. But you have the cross section, and Magdaf gives you, which is a typical situation we are having when we are generating an H and L or an Alp.
Giacomo Polesello: So how how do we do it? So the idea. So the proposal is to normalize to 205 in so using the formula.
Giacomo Polesello: the formula S for the 4 laptop, and to multiply for a factor of approximately 0 point 5 to take into effect, encounter 2 factors, that the running spread of the 3 center of mass energy, and that the Magrave Cross section at the leading order is overestimating the the number of Z at the
Giacomo Polesello: attended 91.2. So this is the essentially the the
Giacomo Polesello: what we agreed, you know, kind of a standing meeting during a coffee break at the at the workshop, and and I think I should stop here, and but you, you have the backup or the the slides, which I already have circulated quite a bit among the H. And L group in which it justifies where this point 4 9 factor comes from.
Juliette Alimena: Thanks a lot, Giacomo. So this is important and affects kind of everyone. So I wanted to make sure that that people got the this message, and, you know, had the the opportunity to to ask questions. And also we will after the meeting, I I can send an email to the the Bsm list to make sure that people who are not in this meeting get this message as well.
Juliette Alimena: So questions.
Sofia Giappichini: Yeah, Hi, I have a question, because, I mean, as you know, we are in the process of publishing our paper on the twitch channels.
Sofia Giappichini: And yeah, we're working on of updating our numbers. But then, is there like a deadline to update also the numbers of lots
Sofia Giappichini: for the Fcc. Reports. If you want the. Of course the plots updated.
Giacomo Polesello: Not sure. Frankly.
Giacomo Polesello: Yeah.
Juliette Alimena: Yeah, it's a good point we can clarify this with with with the conveners.
Rebeca Gonzalez Suarez: Yeah, I mean, I think this ultimately is to be decided by Patricia, Michael and and Emmanuel. Right so.
Rebeca Gonzalez Suarez: But they are not here today, so we cannot have. But I mean the the conversation was with them.
Rebeca Gonzalez Suarez: I don't know then where they want to set the the line, or when we apply this or not so, but this is, it's up to them.
Sofia Giappichini: Okay. Thank you.
Juliette Alimena: I imagine they they care most for the final Fcc. You know, summary document, that things are updated in that.
Juliette Alimena: and that we have to have done totally, totally, perfectly done by the end of March. Is that right, Rebecca?
Giacomo Polesello: No. The 21 of March is when it. This has to be delivered, actually.
Giacomo Polesello: Yeah. So that's why one should ask, because 31 of March. Yeah. I asked Patricia. Recently, 31 of March is really when this thing goes out so.
Juliette Alimena: So I think practically, Sophia. The question. The answer is as soon as possible, of course, but you know, I think if it's done in the next couple 2, 3 weeks, it should be okay.
Giacomo Polesello: Yes.
Rebeca Gonzalez Suarez: It's also a point of why I think, Giacomo, you probably should just circulate an email with a link to this presentation to everybody like in the physics, whatever it's called.
Giacomo Polesello: That was what Juliet was saying. Yeah.
Rebeca Gonzalez Suarez: Yeah, there you go. So.
Juliette Alimena: Yeah, send, you know, all caps email.
Juliette Alimena: And this is the conversation most talk.
Rebeca Gonzalez Suarez: And the conversation can happen in that thing.
Juliette Alimena: Okay. Great.
Giacomo Polesello: Any other questions.
Juliette Alimena: Okay, I'm not hearing any. Thanks, Giacomo.
Juliette Alimena: Let's see. Next on the agenda is Mahmoud.
Juliette Alimena: Can you share your slides?
Mahmoud Ali: Can you hear you.
Juliette Alimena: Yes, I hear you.
Mahmoud Ali: So can I share my screen.
Juliette Alimena: Yes, I believe you should have permission.
Mahmoud Ali: Okay.
Mahmoud Ali: do you see my screen.
Juliette Alimena: Yes, and full screen. Yes, please go ahead.
Mahmoud Ali: Okay, thank you for the opportunity to to give me a talk today.
Mahmoud Ali: So I'm going to talk about reconstruction of millions in standalone system in idea detector. So actually.
Mahmoud Ali: the the aim of our study is to answer this question is standalone. Immune system is able to detect long-lived particle. Just the main system without taking any information from other ideas of detector. So in order to answer this question, we
Mahmoud Ali: have to study the simulation in 2 tracks. At the 1st we sought to do it in fast simulation, using Delphys.
Mahmoud Ali: and also in full simulation, using Dd. 4 Heb. Geometry. Since now we have idea, is fully implemented in Dd 4, Heb, so we can also start to use it to do this study by adopting some Cld tracking algorithm for idea.
Mahmoud Ali: since we still don't have any full reconstruction algorithm in idea. So we might adopt other algorithm in before. So starting with Fast SIM at the beginning, let's have a look about, where is the immune system and what it's consisted of? It is the last sub detector in idea. We have primarily 3 main station
Mahmoud Ali: and 2 ureter nukes at the end of idea, and the technology of the immune system now is microarl is the best candidate up to now, actually choosing. Microarl
Mahmoud Ali: was, was in the aim to to able to have a high space resolution. So we can justify the main system able to to detect some new physics.
Mahmoud Ali: So I will not go in details about the R. And D of the micro. Rl, but primarily we have 3 immune station to return nuke. And this is how the immune system looked like in full simulation. Using the d. 4 Heb, we have a strip each of 1.2 and space resolution around 400 micrometer as we get right now from test beam. But it might be better in future.
Mahmoud Ali: So in the Delphus study, actually using the usual Delphus card for idea. We cannot have this study of standalone immune system, but, thanks to Bidesk, is good about track covariance. We can now
Mahmoud Ali: can do this study by adopting idea card in in actually track covariance. We can choose all the layer of sub detectors just making them as a scattering sub detectors. So we don't take any
Mahmoud Ali: data from them, but instead, we use them just to have a multiple scattering for the drugs. And we only bought immune system as sensitive layer.
Mahmoud Ali: So by this way, if if we have a closer view for our main system, we have 3 layers in gray to return nukes. Primarily so in this study we will try to vary this
Mahmoud Ali: number of layers, and varying also the level arm, and also the spatial resolution for the detector to get the best performance in case of standalone main system reconstruction.
Mahmoud Ali: So I started with a very primary
Mahmoud Ali: input file, just emulating Llbs decaying in in calorie meter around 3 point meter away from the
Mahmoud Ali: from the interaction point exactly at this point, with a million energy varying from 10 gev. Up to 46 gev. So we have 10 K. Events in every one and every event we have at the end 2 millions coming out. It's just an emulating for long lived, but it's not real events for the moment.
Mahmoud Ali: and we have cuts on on the output. We only choose even, which have 2 main and the final and the maximum bt. Of 100 Gv.
Mahmoud Ali: So at the 1st we are varying the number of layers for the immune system, as you can see here at the left. We have at the beginning 3 layers of the immune system and level arm of 30 cm of literary nucleus.
Mahmoud Ali: As you can see, the output for me. Bt. Resolution for the 3 layers. Is not that good, and also not following the
Mahmoud Ali: the Gaussian distribution, we have a Sigma around 0 point 2 8, and by increasing the number of layer we have enhancement in the mean Bt resolution for 4 layer, 5 layer, and even 6 layer. Here all of this output data is 400 micrometer space resolution for the for the detector layer.
Mahmoud Ali: and by varying the level arm. In in this case, instead, we have 30 cm for later nukes between every 2 detection layer. We have now 50 cm, and we can also see some enhancement by varying the level arm, or by varying the distance between detection layer.
Mahmoud Ali: So we now have, for example, for the 3 layers and and the 2 literary nukes around 0 point 2 4. For this mean Bt resolution.
Mahmoud Ali: and by increasing one layer we have 4 layers, detection and 3 return nukes.
Mahmoud Ali: We have 0 point 1 8, and there was an idea to use actually, 4 layers and the last layer of the detection. We don't have a written nuke anymore.
Mahmoud Ali: because it's it's not needed. But at the same time it could be also good for mechanical structure, for the detector. So 4 layer will just 2 return. Nukes have a better enhancement for me in the resolution around ubunt 1, 8, and 1, 2,
Mahmoud Ali: and the last one is varying the space resolution for the detector. So, and fixing the apparatus for 4 layer, and only 2 yokes with 50 cm for liver arm. We have here at 400 micrometer, the 12 ubun 12,
Mahmoud Ali: and for 300 micrometer we have around 0 point 1 1 and increasing, enhancing the space resolution is enhancing more and more resolution, but at the same time enhancing the space. Resolution is requiring more electronics at the output.
Mahmoud Ali: So at the end to summarize for different immune system apparatus and also varying the energy of the mains, we can see this plot is Bt. Against Sigma Bt. For example, in green we have 3 layers, which is the primary design for the immune system, 400 micrometer and the 30 cm level arm.
Mahmoud Ali: You can see here the output of of the primary design is getting better by varying some
Mahmoud Ali: some of the apparatus design, for example, increasing one layer with fixing the the level arm, and again 4 layer, but increasing the level arm from 30 cm to 50, and the last one here in red is enhancing the space resolution up to 200 micrometer.
Mahmoud Ali: The idea is actually, I don't know what is the momentum resolution is required to to
Mahmoud Ali: to stand alone. Main system, reconstruction for long lift particle, I don't know. Is this number actually is good enough or not. But for further development we also right now, I'm studying the Bt against also the resolution. But for the vertex reconstruction, because also, it's important to have an idea
Mahmoud Ali: about reconstruction reconstructing the vertex. I'm also using Medeski code of find vertex.
Mahmoud Ali: I very soon I will have some output. But I also actually wanted to hear from you what are the physics constraints for such a study, but for a standard immune system, because actually, I didn't found anything talking about that, I found some idea about inner detector drift chamber, but for standard immune system is not
Mahmoud Ali: in parallel. I'm repeating all the study again in full, SIM, which will have more accuracy for for multiple scattering. But also in Delphus using bidesky code, we can have the effect of multiple scattering. So the idea. Now, after we have already idea detector implementing, I'm implementing the Cld reconstruction algorithm. Actually, the silicon tracker which is used in inner tracker
Mahmoud Ali: in Cld, I'm implementing it in immune system.
Mahmoud Ali: I hope it could work. Otherwise, I have to write it from scratch algorithm.
Mahmoud Ali: So I finish here. So thank you for your attention.
Juliette Alimena: Great thanks a lot I think this is really interesting, and and of course, really relevant to to the group, because, you know, looking forward, displaced new ones. Is, of course, you know.
Juliette Alimena: highly relevant questions.
Giacomo Polesello: I would have liked to answer his questions rather.
Juliette Alimena: Please!
Giacomo Polesello: Try not not to answer. We don't really have an answer as a group, but we have some some hints. So the point is that I? Yeah, I welcome you also. Yeah, that was the 1st question I wanted to ask you answer while you were halfway through, you answered, I mean, clearly, we need not more as much as the resolution we need the vertex.
Giacomo Polesello: because the reason why we need the resolution is to construct environment masses
Giacomo Polesello: and and to reconstructing via masses. We know where the we know we need to know where the objects are pointing to, and
Giacomo Polesello: as as is, if you don't have a track in the inner detector. Of course you it's somewhere in the kilometer, which is an object which is 2 meters and a half or so we would like to have it a bit more precise than that.
Giacomo Polesello: Hmm!
Giacomo Polesello: Say this, probably I'm not sure we need a a fantastic resolution at all.
Giacomo Polesello: We need to be able to see that there is a particle because
Giacomo Polesello: we don't. We don't have backgrounds.
Giacomo Polesello: or the background will be cosmics or whatever we are speaking of events which are
Giacomo Polesello: which may be completely empty in the inner color, in the color, in the, in the inner detector.
Giacomo Polesello: and have something compatible with the with the muon passing in the in.
Giacomo Polesello: in the calorimeter, in part of the calorimeter.
Giacomo Polesello: So I it's difficult to think of a of an actual background we can simulate for that. I don't know if my colleagues have an opinion, but
Giacomo Polesello: it's it's really a bit difficult to to think of something like that there might be probably a
Giacomo Polesello: Ks to mu mu, perhaps might produce something like that, or no. Kl, S. 12.
Giacomo Polesello: Well, I don't know. Snl where where it splits by having it decaying 2 meters away from the 2 meters away from the, from the, from the interaction point.
Giacomo Polesello: So Patricia is. You want
Giacomo Polesello: want to answer to this question, or.
patrizia azzi: Well, I didn't hear the question. I just joined. I couldn't join before. I'm sorry, and and I think you're discussing the backgrounds.
Giacomo Polesello: Yes.
patrizia azzi: Potential Analysis.
Giacomo Polesello: Yeah, no. The question, yeah. The question by was
Giacomo Polesello: the question we got was, what kind? What is the solution you want?
Giacomo Polesello: And their solution is normally meant to reduce backgrounds and the
Giacomo Polesello: and here it's difficult to to define the backends.
patrizia azzi: Yes, so so. One thing that was missing that has not been done yet, in fact, that we had in our plan when we started. This study is exactly the study just even using Ptr. Throwing ions, you know, in the in the idea. And see, for instance, they punch through via the caloriemeter. Whatever you know comes out anyway, after the caloriemeter, and try to estimate if there was an issue or not.
patrizia azzi: So that is a parallel study that needs to be done now that we have the tools. So yeah, so so that that is one thing and the other resolution was also just. I mean yes, it also to see, I think, that the I mean we asked the question right? So one answer is also just to see how the resolution on the vertex changes as a function of the dimensions.
patrizia azzi: you know. Of course, it's important, the signal to background. But also, it's important to know can we do it, what can we do? And what is the dimension of the detector just to have an idea? Because.
Giacomo Polesello: And I couldn't.
patrizia azzi: Was never considered even before. So that answer is already good for, for now.
Giacomo Polesello: It would be. It would be lovely to see something which looks like a pig indeed.
Giacomo Polesello: And the yeah, you were asking me, actually, you were asking me last week, actually.
patrizia azzi: Yes, exactly. About.
Giacomo Polesello: You're asking me, and I put some thinking on it.
patrizia azzi: Okay.
Giacomo Polesello: And because, indeed, the 2 2 obvious benchmarks, one is the
Giacomo Polesello: the H and L going to me to Semi electronic, to new ones.
Giacomo Polesello: That one is very interesting, because there is nothing.
Giacomo Polesello: and and the and the 2 mules don't make a peak. But if you know where the vertex is, you can.
Giacomo Polesello: You can try to to recon. You can try to reconstruct, to pick from from the missing energy, and that that would be very. That would be a super cute thing.
patrizia azzi: Exactly. Yes.
Giacomo Polesello: Because that one would have also the position of the vectors would have a double impact on the system. If I can give you the mathematics. If you want the other one, I would think isn't what
Giacomo Polesello: Safa is. Gonna show soon. But Safa is gonna show soon is not long lived, but but there is a benchmark which which can be long lived.
Giacomo Polesello: and there that would be another kind of kind of interesting, because there you would have a mono, a monochromatic photon
Giacomo Polesello: from the vertex and and the 2 mules would have a would have a
Giacomo Polesello: should create a peak of the particles on the Jeff scale.
Giacomo Polesello: So if one could be, could be able to show that, and that I don't think it's very easy to them to get the background, and that should be easy to
Giacomo Polesello: to if one can show a peak like that. So we we can perhaps discuss then how to how to.
Giacomo Polesello: We can provide you with a adm for hype events to
Giacomo Polesello: to be sent into into the simulation.
patrizia azzi: Yeah, that's great. And now that we have, you know all this work that Mahmud has done
patrizia azzi: doing the physics is the is the fun part.
Giacomo Polesello: Not easy.
patrizia azzi: So so. Yes, certainly I think it would. I think that that for now the immediate thing, it would be nice just to have this idea of the vertex. I haven't seen the presentation, so I don't know if it's shown a resolution of the vertex.
patrizia azzi: No, just as a capacity
patrizia azzi: of how this resolution changes as a function of some dimensions, because, of course, some detector people say, Oh, but we cannot do it so small, etc. So just to have an idea of the behavior, and then, of course, for the Pretdr. Then, you know, it would be. Now we should start with the physics, and then, we might even, you know, make a really use case of having
patrizia azzi: this new undetector stand alone. That maybe has other things more than this. Who knows? So you know this famous Bsm detector concept that that we don't have yet so so.
Giacomo Polesello: Yeah, yeah.
patrizia azzi: We will be doing it. Yes, now I mean.
Giacomo Polesello: You know, because for a parameter point of view, this would
Giacomo Polesello: would stand the towards the low
Giacomo Polesello: to too low, low to low coupling. What we can do.
patrizia azzi: Yes, exactly. It extends by far. Yeah.
Giacomo Polesello: Not, unfortunately unfortunately, is not by far. It extends it by factor of 2. But the impact on the parameters is because of the exponential is is much less. But I think it's it's very, very nice to show.
patrizia azzi: Yeah, it's complementary also to anyone else, any other experiment. So it's a place where we we have to push as much as possible. Then I think, once we know what is the resolution that we would like to have. Then, you know, the the hardware people, the detector people might think of solutions
patrizia azzi: to achieve that, you know, instead of just saying, I make a small thing, but maybe you have it in a different reconstruction. You do. You know other games with software, and then you think.
patrizia azzi: but until you don't know how much you need, it's it's always, you know, it's always a bit difficult. So, having this benchmarks from the physics will be great. And so I think that we just you know, we're in touch. And Mahmoud is the person that is driving this type of this type of studies. If if it's okay with him.
Mahmoud Ali: Yeah, sure, I just have a comment about the space resolution required from detector as a study. We have done in full. SIM, actually, in idea, we have
Mahmoud Ali: a big effect from multiple scattering, which is is smearing the tracks up to 500 micrometer. That is the output. So if we have a detector with a space resolution
Mahmoud Ali: for around 600 micrometers. Then you have a problem, because the effect of multiple scattering is huge. And now also is a new layout of idea. We have an extra crystal dwelled out calorimeter, so that will also increase the impact of multiple scattering. So
Mahmoud Ali: I think also, space resolution is important at at one threshold, let's say, up to now it's 500 micrometer.
Mahmoud Ali: Then.
patrizia azzi: Yeah. And then also the momentum of the of the tracks.
Mahmoud Ali: Yes.
patrizia azzi: Yeah, yeah, no. We yeah, we need to do the study. That is very important. What you're saying, absolutely, absolutely. That's why we need the material, the full seam. And then this, this material also will impact the potential background, of course, that you might have.
Mahmoud Ali: I would be happy actually to do some physics
Mahmoud Ali: in that one. But I I have some output for the vertex, but it is still not ready to to show. So maybe next meeting I
Mahmoud Ali: okay.
patrizia azzi: It will come.
Mahmoud Ali: Yeah.
Juliette Alimena: Okay, great. We've had a bit of a discussion already. But are there more questions for Mahmoud?
Mahmoud Ali: Yeah.
Juliette Alimena: Okay, I'm not hearing any, but I I hope also this discussion helped. Answer your questions, Mahmoud.
Mahmoud Ali: Okay. Thanks.
Juliette Alimena: Thanks a lot.
Mahmoud Ali: Okay. Great.
Juliette Alimena: But also please upload your slides to the agenda.
Juliette Alimena: Okay, I will do it. Thanks much.
Juliette Alimena: Okay. Then the next talk is from Safa.
Safa Naseem: Hi, I'm just gonna share my screen. Perfect.
Safa Naseem: Alright, I think it should be visible now.
Juliette Alimena: It is. Please go ahead.
Safa Naseem: Perfect. Okay? So 1st of all, thank you for giving me the chance to speak on behalf of my group.
Safa Naseem: And yeah. So I'm going to be talking about the searches for Alps via the Meon channel at the Fccee.
Safa Naseem: and the reason we're going for Alps is because, 1st of all, it's an indication of new physics, and it tends to appear in theories with spontaneously broken global symmetries.
Safa Naseem: Also the the reason why Alps are so ideal for studies like this is because they have pretty much. They give us free reign over the face space that you know. It's it's unconstrained phase space, which means it gives us more freedom to play with the mass and the couplings
Safa Naseem: unlike in the case of Qcd. Axions. I don't know if I said Alps or axion, like particles sorry and depending on which part of the phase space we want to study, we tend to go for different search strategies. So in the case of
Safa Naseem: high energy colliders such as the Fcc. Would be, we can probe, you know, the sensitive parts of the phase space that are inaccessible at lower energies.
Safa Naseem: And so this tends to make it a very nice study.
Safa Naseem: So the Lagrangian of the theory that we're studying the idea comes from Bauer's paper that is listed here.
Safa Naseem: And the paper. There's 2 papers. Actually, there's 1 from 2,018, and there's 1 from 2,017,
Safa Naseem: and the effective Lagrangian of the theory is given in the 1st 2 lines. The 3rd term here defines the couplings between the axion, the alp, and the fermions. And the 4th term here in the second line is the coupling between the Alp and
Safa Naseem: Guan guons, and then the rest is the vector Bosons. And then, after electroweak symmetry breaking, we get the effective Lagrangian in the shape of the 3rd line, where we define the interactions between the axions and photons and the Z. Boson and the Wilson coefficients at tree levels are defined by this line here.
Safa Naseem: and the effective. The loop couplings at the loop level are defined by the definitions here. These are all taken from Bauer's paper. Okay
Safa Naseem: for the initial benchmark for the initial study. We assume that cff which is the coupling of the axion to all fermions is set to 0, except for in the case of leptons, and we assume that all other Wilson coefficients at tree level are set to 0,
Safa Naseem: and the coupling to generate to the couplings of the axion to Z are generated by radiative corrections, and require 2 parameters, which is the mass of the Alp and the coupling to the Leptons, and they, like, I like, as mentioned in the previous slide, are defined by these loop, effective loop couplings. Here.
Safa Naseem: in the case of the study here our branching ratio is dominated by the axion
Safa Naseem: going to 2 photons, and in the case of amongst the decay channels for the Leptons, it will be dominated by the heaviest open Lepton, which basically means that if the axion is twice the mass of said Lepton, it would be able to kinematically decay into the Lepton. Otherwise it won't be
Safa Naseem: I'm gonna move on to the Feynman diagrams
Safa Naseem: the Feynman diagrams for the events that we're studying. The signal event is on the left, which is an electron positron going to a Z boson, and the Z. Boson then decays into an Alp and a photon, and then the Alp can decay further into 2 leptons. For the purpose of this study we're going for mu plus and mu minus.
Safa Naseem: And this, an example of a background event is on the right hand side with a similar process, but with just standard model interactions.
Safa Naseem: So for the purpose of our study. The signal and background Mc productions were done using mad graph
Safa Naseem: for a mass interval of 0 point 2 5 to 3.5 Gevs. Which is just below the threshold of the Tau. You know it's less than twice the mass of the Tau
Safa Naseem: Tau, Lepton, and the branching ratio. In our case for the Alp going to Lepton Mu, one anti muon pair is 100% and the standard the center of mass energy is 91.2, which is the Z. Pole.
Safa Naseem: and it was normal, and it would be normalized to 6 into 10 to the 12 Z's. The Mc samples were generated using mad graph 3.5 point 6,
Safa Naseem: and the Ufo files for the generation were provided by Bauer and his co-authors. The Fcc. Analysis framework was used for generating the root files from Pythia, a 10 Delphi simulation, and we used the idea, winter 2023. Card for this
Safa Naseem: and the event. Preselection cuts that were applied were that we would only select events where the number of reconstructed Muons were. There were 2 reconstructed Muons in the final State and one reconstructed photon, and we applied a monochromaticity cut
Safa Naseem: where the energy of the reconstructed photon would be greater than 42, since we expected a peak at roughly half the center of mass energy. So approximately 45 Gvs.
Safa Naseem: okay.
Safa Naseem: so if I go into the kinematics, we studied the kinematics and one of the 1st things we did was, we tried to reconstruct the invariant mass. In our case, for the purpose of our study, we consider the mass of the Alp to be 2 Gbs, and you can see here that the reconstructed mass clearly has a peak at 2 Gb, so that was good.
Safa Naseem: And then this is, these are the distributions for Delta R, for a combination of for different combinations of the 3 final state particles. So on the top left we have delta R for the 1st muon and the photon top right is second muon and photon, and the bottom is the 1st and the second Muons. So as you can see.
Safa Naseem: it is very. You can.
Safa Naseem: You know, you can differentiate between the signal and the background. And we can actually play
Safa Naseem: exact cuts, and to see which parts of the which sorry which regions of Delta are, give us a dominating signal over the background ratio.
Safa Naseem: Similar kinematic studies were done for other kinematic distributions, for in this case, such as the 1st mu one. So we have over here on the top left the Phi.
Safa Naseem: and then you have the Ada
Safa Naseem: of the 1st muon, and then you have the theta, the bottom. You have the energy and the bottom right? You have the Pt. And in all cases you can clearly see where the signal is in excess of the background, and you can apply your cuts.
Safa Naseem: This is a similar study for the Muons, the second Muon.
Safa Naseem: And over here we have the distributions for the photon. Just a quick comment on the reconstructed. The energy of the reconstructed photon. Here, you can see is, there is a very clear peak at around 45 Gbs. And there's nothing below 42. And that is because we applied the monochromaticity cut because there was, you know, if you don't apply the cut, you sort of see this like tapering off
Safa Naseem: over here, which is unnecessary. We wanted to see. We knew where, what peaks we wanted to look at, and we wanted to clear out the background. And so that is very evident here.
Safa Naseem: The next thing we wanted to study was the phase space as a function of C. Tau, which is the decay length, and the Dk length, as we know, is inversely proportional to the Dk width which is given by this expression here, and this expression is also taken from Bauer's paper, which relates the Cll. Which is the coupling responsible for the decay of the Alp to Muons and the mass of the Alp.
Safa Naseem: and what you can see is the higher, the coupling, the lower the sorry. Yeah, the higher the coupling, the more prompt the decay, and in this case the dashed line here represents the radius of the detector. The length of the detector. Sorry, which is 2 meters.
Safa Naseem: So we expect that everything above the dash line is, you know, is included or is is valid and we want. And that's our area of interest.
Safa Naseem: And for the purpose of our studies, we, our couplings, were roughly 10 to the 10 raised to the minus one, and that falls within the range that we
Safa Naseem: so that is acceptable within the detector.
Safa Naseem: We also performed Bdt analysis to study the mass, to study the coupling versus mass phase space. And we used Xgb, which is a powerful algorithm
Safa Naseem: and we produced an exclusion plot and to indicate the lowest coupling that can be probed at different masses for the range in question. Again, the range that we are talking about is 0 point 2 5 to 3.5 gevs.
Safa Naseem: And the features that were used for training our Xgb algorithm, the machine learning algorithm were as follows, the ones that are mentioned here. It's the mass of the Alp, the energy of the reconstructed photon, the minima between either the ratios of the 1st to the second muon, or the second to the first.st Muon. Sorry. That's a typo.
Safa Naseem: and the theta of the Alp
Safa Naseem: and the Theta and Phi for the 1st muon, which was rotated in the frame where the Phi of the photon is 0, and it's also boosted to the rest frame of the Alp. So these are the 6 variables or features that were used for training our data set.
Safa Naseem: and once that was done, we get a plot, which is the red line. So the green line here is the results from the Babar experiment
Safa Naseem: and the blue line. Here is the beam dump experiment. The turquoise line is the contour that represents the mass and couplings for events where 3 events were detected by the detector taking into account the number of Alps produced, and the detector probability, the detection, probability sorry. And
Safa Naseem: and so this is the results. The red line, of course, is the result of our work.
Safa Naseem: which is, it's roughly 10 to the minus one, which is good
Safa Naseem: and the mass range that we are we were considering.
Safa Naseem: Okay, in conclusion, what we are currently working on is we're finalizing the analysis and the work for for the analysis of the 2 muons. Work is ongoing, for
Safa Naseem: Alp is going to electron positron. That is what we're working on. Next, one of the preliminary plots that I've already produced, which is similar to what I showed you earlier. But in that case it was for mu one anti mu. One is the electron positron, and over here you can see there is a much smaller phase space for this given range of masses from 0 point 2 5 to 3.5. However, we're also looking at a mass interval, a smaller mass interval for long lived particles
Safa Naseem: which would be between one to 220 Mevs.
Safa Naseem: And we're also working on the photophobic case where we set C. Gamma Gamma to 0. And if I can go back to the relation between C. Gamma, Gamma, cww, and Cbb, you would see that if we set this to 0 we would end up with Cww equals to minus. Cbb.
Safa Naseem: so that is what we're. So that's photophobic case. And in that case the branching ratio, of course, given that the coupling is 0, the branching ratio of the Alp going to photons will be 0. But the coupling between the Alp, the Z boson, and the photon can be large, and the parameters of interest for that study would be Cww. Cee and the mass of the Alp.
Safa Naseem: So that's it from my side. Thank you for listening, and if you have any questions I'll try to answer them.
Juliette Alimena: Thanks so much. Shafa, this is really nice progress.
Juliette Alimena: Yeah, I didn't even realize you were doing a Pd Pdt analysis. So that's really nice?
Juliette Alimena: I have a question or 2, but maybe I we go to other people first, st are there questions?
Juliette Alimena: Okay, while they think of them? And then I ask so the you said this monochromatic? No, what is it?
Safa Naseem: Yeah. Sorry.
Juliette Alimena: Yeah, I'm sorry I must have missed it. Can you explain that again, and what it is, and how you get that translates to the Rico photon energy being greater than 42 Gv.
Safa Naseem: So maybe others can also answer. But I can answer, I can give a brief answer. So the monochromaticity cut is the cut we've applied, which is on the energy energy of the reconstructed photon.
Safa Naseem: Where we set the we say that we don't want anything below 42 Gevs. And that was roughly because we knew that we would get a peak at 45 Gvs. Which is half the center of mass energy. So we were expecting a peak if I can show you the plot again. So we were expecting this. But when we don't apply this, we just have
Safa Naseem: energy peaks, basically background all over, and so we wanted to get rid of that, just to cut down on the background.
Juliette Alimena: Okay. So you're just.
Giacomo Polesello: I can answer to you the physics of it.
Safa Naseem: Right.
Giacomo Polesello: It's A. It's a two-body decays of the Z, which is a 90 jeff particle into a 1 Jeff. Particle and something else.
Giacomo Polesello: Then there is a recoil formula which says that the momentum of the something else is equal to the mass of the Z square, minus the mass of the particle.
Giacomo Polesello: This particle, the essence you are producing, which in our case is 0, is one compared to 90, divided by twice the mass of the Z, so basically, the the momentum of the photon recoiling is exactly the mass of the Z, divided by 2.
Juliette Alimena: Right.
Giacomo Polesello: So in our, since we are, you have, we have an interval between
Giacomo Polesello: below to 3.5 gev, and so that the
Giacomo Polesello: it's it's basically we. The the recoil photon is never below 45 gel.
Juliette Alimena: Okay. So then, 42, there's nothing special about the number 42.
Giacomo Polesello: 42 is related to the resolution of the calometer. Yeah, of course.
Juliette Alimena: Okay.
Giacomo Polesello: No, that's what you want. Fine! No, it's a.
Juliette Alimena: I thought there was a direct link between monochromastis.
Giacomo Polesello: We want to. Then to. This is the cut at the generation level, and we want to leave some some margin for the.
Safa Naseem: Leaves.
Rachik : For the calimeter resolution.
Rachik : Sorry it a little bit. Yeah.
Juliette Alimena: Okay. Great.
Juliette Alimena: Sorry.
Rachik : Don't worry.
Safa Naseem: Yeah, so this.
Juliette Alimena: Okay.
Safa Naseem: 3, 5, and then we have a little bit of a leeway to sort of get the full peak. Yeah.
Juliette Alimena: Hmm.
Juliette Alimena: then maybe I can just go ahead and ask my my second question, so on your results, the the limits the red curve.
Juliette Alimena: You had a bit, you have a bit of a jump at I don't know which mass this is towards the
Juliette Alimena: yes, yeah. Right there! Do you know what that's coming from?
Safa Naseem: That might have been a statistical error that might have been me just plotting the wrong number here. But it's there's not supposed to be a a jump here. Yeah, there's supposed to be. It's supposed to be roughly.
Giacomo Polesello: Well, it's a
Giacomo Polesello: also, when you are doing the the Gb. It it changes, the the shape is changing. We are. We are going to Vanier
Giacomo Polesello: near one typically with x to be so. So it's there is a certain level of fluctuation. Typically, this is big, I agree. But
Safa Naseem: Yeah, no, that is clearly my mistake. You know, it's it's got nothing to do with the physics of it. Yeah.
Juliette Alimena: Okay, worth at least double checking, I'd say.
Safa Naseem: -
Juliette Alimena: Other questions.
Juliette Alimena: Yes. Odin.
Odin Schneider: So I had a question with the signal. So you're having this annihilation to a Z, and then have the outcome from there. But did you also look at? One could imagine, like a diagram where we have an Isr photon
Odin Schneider: rather than the photon coming from the Z, and then the electron and positron annihilating directly to an Alp.
Odin Schneider: Did you look at that? Or is there any comparison for for that signal
Odin Schneider: creating a muon? And the photon compared to this via the Z. Bozon.
Giacomo Polesello: Yeah, this is this is explained in the paper by Bao Etal.
Giacomo Polesello: They
Giacomo Polesello: they examined whether it's whether the cross section, what is the dominant co-section, whether in decay of the Z or in the resonant decay. Resonant? Yeah, in the resonant decay in which okay? 2, as you say, plus e minus goes into
Giacomo Polesello: goes into an A, and then the A decays to mu mu, and they show that this is basically negligible with respect to the Z decay.
Odin Schneider: Okay. Thank you.
Juliette Alimena: Elnora.
Elnura Bakhishova: Hi! Can you hear me?
Juliette Alimena: Okay, perfect. I just had a small question. Regarding the top plot.
Elnura Bakhishova: On Slide 9. If you could maybe show it again.
Safa Naseem: One second, I'm gonna try to scroll back. Yeah.
Elnura Bakhishova: Yeah, exactly. Yeah. I was just wondering there. So there seems to be a cut, a cut at like 2.6 or something, and
Elnura Bakhishova: I was just one.
Safa Naseem: 32.
Elnura Bakhishova: Sorry, what.
Safa Naseem: Which plot are you referring to on this slide.
Elnura Bakhishova: Oh, M. The Rico photon. Eta! But
Elnura Bakhishova: so there is a cut at 2.6. I think I was wondering where this is coming from. Because I think in the idea cart, it's set to 3.0. And yeah, I was wondering whether you guys applied that cut order or whether it's coming from that graph or something.
Safa Naseem: That's a nice pick. Yeah, we we did actually apply a cut at the Matte graph stage where we set the eta of the photon to 2.6.
Elnura Bakhishova: Okay, and
Giacomo Polesello: Was there.
Elnura Bakhishova: What about the Pythia Photons?
Giacomo Polesello: Well, the and the well. The reason we are the
Giacomo Polesello: we record. 2.6 is the coverage of the inner detector.
Giacomo Polesello: So we require that.
Giacomo Polesello: So in order to have a reconstructed photon, we have, we have to be 2 tracks for for me to show. The
Giacomo Polesello: the reconstructed photon by definition is defined only within eta, 2.6.
Elnura Bakhishova: Okay.
Elnura Bakhishova: Okay. Thank you.
Giacomo Polesello: The kilometer goes up to 3, of course, but
Giacomo Polesello: we don't know if it's a photon electron lower than that.
Elnura Bakhishova: Okay.
Juliette Alimena: Other questions.
Juliette Alimena: Okay, I'm not hearing any. Thanks again. Safa.
Juliette Alimena: And yeah, any other. Any other business.
Juliette Alimena: Okay? If not, we close the meeting here. Thank you to to well, I was going to say both speakers, but also to to Giacomo for presenting the important news that we will then also send an email to to make sure that everyone gets gets the news about the normalization. If you're doing an analysis at the Z poll.
Juliette Alimena: okay, thanks everyone, and as always, let us know if you want to present your your results, even if they're work, it's work in progress.
Juliette Alimena: Thank you.
David d'Enterria: Bye-bye.
Juliette Alimena: Bye.
Mahmoud Ali: Thanks, bye.