WEBVTT 1 00:00:00.000 --> 00:00:09.000 If not, then let's thank Zach for the nice presentation again. And we move on to our next speaker. Who will be speaking about new sustainable alternatives for sustainable for future colitis. 2 00:00:09.000 --> 00:00:14.000 Your timer will start and you will hear the jingle Go ahead. 3 00:00:14.000 --> 00:00:18.000 Hello, can you hear me? 4 00:00:18.000 --> 00:00:19.000 Yes. 5 00:00:19.000 --> 00:00:26.000 Yeah. Hello, everyone. Firstly, I would like to thank the organizers for giving me this opportunity to present our work. 6 00:00:26.000 --> 00:00:32.000 As mentioned, I'll be talking about enhancing the light and weakly coupled new physics program. 7 00:00:32.000 --> 00:00:45.000 At future colliders with sustainable alternatives. It is mostly along the lines of how to make the most out of the existing or future collider infrastructures. 8 00:00:45.000 --> 00:00:52.000 Let me begin with… our goals in high energy physics. So after the Higgs boson discovery. 9 00:00:52.000 --> 00:00:59.000 We have mostly a complete picture of the standard model of particle physics, but there are still many missing pieces. 10 00:00:59.000 --> 00:01:08.000 And one of our main goals is to any hint of physics beyond the standard model in order to tie these missing pieces together. 11 00:01:08.000 --> 00:01:27.000 In doing so, when we explore the mass and the coupling strength parameter space of new physics, the large mass and the higher coupling strength region is relatively more explored as compared to the weakly coupled like new physics, which is going to be a focus 12 00:01:27.000 --> 00:01:50.000 Of our talk today. And when we talk about weekly couple light new physics, the obvious benchmark that comes to our mind are long-lived particles because of couplings They mostly have long lifetimes such that they do not promptly decay in colliders. They travel some distance and then they decay either 13 00:01:50.000 --> 00:01:57.000 Giving us a secondary vertex inside the detector or they can even decay outside the detector if they are light enough. 14 00:01:57.000 --> 00:02:14.000 To be boosted. So the reasons for long lifetimes, they exist very much in our standard model. We have many long-lived particles in standard model. So you have to have a suppressed DKVIT to gain lifetimes. And these are also very well motivated in 15 00:02:14.000 --> 00:02:28.000 Many BSM models. Moving on, this slide provides a snapshot of various collider signatures of long-lived particles from displaced vertices to muon spectrometer clusters. 16 00:02:28.000 --> 00:02:40.000 And so the interesting thing about long-lived particles is that the signatures heavily depend on where these particles decay and what it decays into. 17 00:02:40.000 --> 00:02:51.000 But now what about the decays happening outside the collider detectors? And this plot here shows that for very light and long-lived particles, this can happen quite often. 18 00:02:51.000 --> 00:02:56.000 This plot shows the distribution of the decay length in the lap frame. 19 00:02:56.000 --> 00:03:02.000 And after some point around 10 meters or so, the main collider detectors lose sensitivity. 20 00:03:02.000 --> 00:03:13.000 So in those scenarios, dedicated detectives placed either in the forward or transverse directions away from the interactions point interactions point provide sensitivity. 21 00:03:13.000 --> 00:03:23.000 You must be familiar with many dedicated detective proposals like Mathus Law, Codeigsby, or even the phaser detector which is already taking data for run 3. 22 00:03:23.000 --> 00:03:43.000 There are multiple dedicated detectors proposed and With today's talk, I would be trying to motivate that why optimization of these dedicated detectors is required so that we just have enough to gain sensitivity to new physics. 23 00:03:43.000 --> 00:03:55.000 There have already been a number of interesting talks in this workshop about sustainable future colliders and I have just put a list out here. 24 00:03:55.000 --> 00:04:04.000 If you are interested. But today I'll be talking about how can we be sustainable in our efforts to probe the light and weakly coupled region. 25 00:04:04.000 --> 00:04:11.000 And these are some ideas to gain sensitivity to the light and weakly coupled region. 26 00:04:11.000 --> 00:04:17.000 The first one is to utilize the existing facilities to the fullest. 27 00:04:17.000 --> 00:04:42.000 To look for unusual signatures. Second is to optimize the dedicated detectors and find out what is the minimal requirement for these dedicated detectors to improve performance over the already existing or proposed main collider detectors. And we also talk about a shared detector concept for the FCCEE and FCCHH. 28 00:04:42.000 --> 00:04:51.000 And lastly, we will also highlight how to use a high pileup environment to our advantage. 29 00:04:51.000 --> 00:05:05.000 To illustrate all these ideas, we'll be using the long-lived particles in the Higgs portal as our benchmark model where we extend the standard model with just a scalar light scalar particle. 30 00:05:05.000 --> 00:05:28.000 Which interacts with the Higgs boson. So the mixing is highly constrained from existing low energy experiments, but it can also have a trilinear coupling with the standard model Higgs boson which is not severely constrained and this scenario gives long-lived signatures of the fund. 31 00:05:28.000 --> 00:05:46.000 Decay. So for production, if you have enough, if you have a considerable value of the trilinear coupling, you can produce it from Higgs boson decays or you can also produce it from meson decays from the mixing term. 32 00:05:46.000 --> 00:06:01.000 Now, the first idea is to utilize existing facilities to the fullest to look for unusual signatures. For example, let us look at the CMS zero degree calorimeters which are located around 140 meters away from the interaction point, the IP5. 33 00:06:01.000 --> 00:06:12.000 And the good thing is they have two ZDCs on either side of the interaction point and this could be sensitive to very forward physics because it's etc. 34 00:06:12.000 --> 00:06:24.000 Very high pseudorapidity and all the charged particles are typically deflected away by magnets before they reach the ZDC. So it is at least there is no charged particle background there. 35 00:06:24.000 --> 00:06:31.000 So what we propose in this work is can we modify the Z disease at the high luminosity latency? 36 00:06:31.000 --> 00:06:48.000 To gain sensitivity for long-lived particles, there could be, of course, some possible backgrounds. We have contacted this proposal idea with CTC members to receive their feedback and then we just need to put trackers to enhance sensitivity. 37 00:06:48.000 --> 00:06:54.000 And just to give you an idea of its performance with respect to the phaser for the dark scalar model that I explained. 38 00:06:54.000 --> 00:07:11.000 It really gives some improvement in performance with respect to the phaser detector because it's much closer to the interaction point and the enhancement is especially for heavy LLPs with low ZTO. 39 00:07:11.000 --> 00:07:20.000 Now, the second point is the optimization of dedicated detectors at LHCR, high luminosity LHC, the infrastructure is already there. 40 00:07:20.000 --> 00:07:27.000 So mostly these dedicated detectors are placed in any empty shafts or available halls around the main detectors. 41 00:07:27.000 --> 00:07:32.000 Which need not be optimal for the LLP models beyond the standard model. 42 00:07:32.000 --> 00:07:37.000 But with future colliders, we have this advantage that they are in their conceptual design phase now. 43 00:07:37.000 --> 00:07:46.000 So we can optimize their design and integrate These dedicated LLP detectors with the main detector design, even if the funds are not available for now. 44 00:07:46.000 --> 00:07:54.000 Cern can reserve the positions based on these studies for integrating them in future. 45 00:07:54.000 --> 00:08:09.000 So in this regard, we propose two detectors, one in the transverse direction called delight and one in the forward direction called forehand for the FCC HH initially, but then we also studied their performance at the FCCE. 46 00:08:09.000 --> 00:08:19.000 Collider. And let me discuss a bit what I mean about optimization for in respect to the delight detector here. 47 00:08:19.000 --> 00:08:40.000 So this is the HL LHC projection for the model that we discussed, the dark scalar mass in the x-axis and the lifetime in the y-axis. And we see that there is a gap here for light mass and heavy high C tau values which the FCCEE IDA detector can 48 00:08:40.000 --> 00:08:50.000 Probe a little bit but a gap still remains. And the question is, can a dedicated detector probe this region. 49 00:08:50.000 --> 00:09:04.000 So now in this direction, we optimize the delay data. We start from a very big detector, but the idea is to slowly decrease the parameters and move it farther away from the interaction point and see what is the minimal design 50 00:09:04.000 --> 00:09:18.000 To have at least the same efficiency as the idea main detector. If we place it somewhere which doesn't gain in terms of the idea main detector there is no point of having this, building this dedicated detective. 51 00:09:18.000 --> 00:09:31.000 So we calculate a gain with respect to the FCC EE IDR detector performance and we identify this We show here in these plots how this game varies. 52 00:09:31.000 --> 00:09:44.000 And we also identify a minimal design called the core delight in this. You can find more details in this work here, which we also submitted for the European strategy proposal. 53 00:09:44.000 --> 00:09:56.000 The third idea is to have a shared detector concept for FCCE and FCC HH. So the question is, can we use this transverse detector at both FCCE and FCCHH. 54 00:09:56.000 --> 00:10:12.000 And since if you place it in a separate cavern which is parallel to both the to the experimental cavern which houses both the FCCE and FCChh detectors, then we can actually use it for both. 55 00:10:12.000 --> 00:10:18.000 And this opportunity to reuse an entire detector at FCC EE is really impressive. 56 00:10:18.000 --> 00:10:29.000 And it will maximize resource utilization and it will promote sustainability in high energy physics because for both the experiments we can reuse this dedicated detector. 57 00:10:29.000 --> 00:10:41.000 Which is already optimized. And these are simple detectors with RPCs and scintillators as its major components. So use of eco-friend RPCs. 58 00:10:41.000 --> 00:10:47.000 Would be very useful here as we also heard from a talk this morning. 59 00:10:47.000 --> 00:10:53.000 And in terms of performance, we see, if you remember these grid plots which I showed a couple of slides back. 60 00:10:53.000 --> 00:11:08.000 These detectors, they… really enhance the performance to light and displace new physics, both at FCCE in the left panel and the performance for the FCC HH is shown in the right palate. 61 00:11:08.000 --> 00:11:20.000 I'll now go to the final point of using a high pileup environment to our advantage. So future Hedron colliders are high luminosity machines and high instantaneous luminosity means a high value pileup. 62 00:11:20.000 --> 00:11:31.000 And Pileup has always been seen as a nuisance because it adversely impacts resolutions of experimentally measured observables which are essential to distinguish BSM signals. 63 00:11:31.000 --> 00:11:40.000 And this effect is even more for light new physics which is even indistinguishable from the pilot events because of the low energy scales. 64 00:11:40.000 --> 00:11:50.000 But what about light new physics coming from Maison decays, which can be there if you have a mixing with Higgs or some model like that. 65 00:11:50.000 --> 00:12:06.000 Because as you increase the number of pilot disks. This table shows that the number of B headrons produced per bunch crossing or even D hedrons that increases. And this increase has to be taken into account when we calculate the efficiency of these 66 00:12:06.000 --> 00:12:14.000 Llps because there is an increase in the production rate of these LSPs from the B&T and so on. 67 00:12:14.000 --> 00:12:20.000 Time is up. There's only the summary slide left. 68 00:12:20.000 --> 00:12:27.000 But yeah, so the idea here is to increase the efficiency of detecting LLPs in various detectors per bench crossing. 69 00:12:27.000 --> 00:12:33.000 And if we carefully include this in our studies, we might discover hints of light new physics sooner than expected. 70 00:12:33.000 --> 00:12:55.000 That brings me to the summary. In our endeavors to look for hints for new physics. It is very essential to achieve sustainability without compromising our physics needs and This workshop has been a great collection of many interesting talks and a very detailed 71 00:12:55.000 --> 00:13:03.000 Studies and in this talk we discuss a few sustainable approaches for probing the light weakly coupled regime. 72 00:13:03.000 --> 00:13:20.000 Leading to displaced signatures. Um and I hope that these could benefit our This could benefit the preliminary studies of the future circular colliders and integrating the LLP detector. 73 00:13:20.000 --> 00:13:24.000 Designs. Thank you for your attention. 74 00:13:24.000 --> 00:13:35.000 Thank you, for this really interesting talk. Do we have any questions? 75 00:13:35.000 --> 00:13:39.000 So I guess while people are still thinking, I had a question of my own. 76 00:13:39.000 --> 00:13:54.000 For the discussion with ZDC. I was just curious if you have had any preliminary feedback from them Because, I mean, this is really cool to see 77 00:13:54.000 --> 00:14:04.000 Yes, but we still have not received any feedback, but they have acknowledged that this could be an interesting thing at the HLL-HC. 78 00:14:04.000 --> 00:14:05.000 Oh. 79 00:14:05.000 --> 00:14:14.000 Okay, cool. And I guess you have already put in the other detectors in the European strategy update or what's the plan from now onward 80 00:14:14.000 --> 00:14:34.000 Yes. I mean, from now onward, the plan is to actually do concrete background studies for all these proposals, like for ZDZ, there could be the standard model neutral little piece background So we want to study them also for delight for this shared detector that 81 00:14:34.000 --> 00:14:45.000 I showed it would be important to understand what the background here is so that is our next step. 82 00:14:45.000 --> 00:14:46.000 Cool. 83 00:14:46.000 --> 00:14:57.000 Oh, in this regard. But yes, I mean, we are of waiting to hear i mean we are we would be happy to hear any experimental input. We would really appreciate 84 00:14:57.000 --> 00:15:01.000 Perfect. Hopefully you get more feedback in the coming months. If there are any other question for Toja at this point? 85 00:15:01.000 --> 00:15:06.000 Thank you. 86 00:15:06.000 --> 00:15:06.879 If not, I would suggest you can post your questions later in the chat as well. And we thank her again and move forward with our next speaker, which is going to be Maria.