1 00:00:00,210 --> 00:00:00,600 Okay, 2 00:00:01,230 --> 00:00:05,190 so thanks a lot first of all to the organizers for for the invitation to give 3 00:00:05,190 --> 00:00:12,000 a talk on the X 17 access measure by by any 64 experiments. So we are a non Alexey 4 00:00:12,000 --> 00:00:16,200 experiments I will try to give an overview of why these kind of services are 5 00:00:16,200 --> 00:00:22,980 internecine and a beat to try to explain very quickly, what is m 64 experiment? So, 6 00:00:22,980 --> 00:00:28,260 first of all, where do we put these kind of searches are inside what is called a 7 00:00:28,260 --> 00:00:32,760 Dark Sector framework. It's an interesting framework to explain the origin or for 8 00:00:32,760 --> 00:00:38,640 that matter and it is based on the existence of weakly for force apart from 9 00:00:38,640 --> 00:00:44,670 gravity which couple the standard mother and and the dad market and then these that 10 00:00:44,670 --> 00:00:49,710 sector they can be gay into that method can be days. So, among all the landscaper 11 00:00:49,710 --> 00:00:54,510 of that sector that you can see, I don't know if you see my mouse, maybe one 12 00:00:54,510 --> 00:00:58,770 second. Maybe now you see my mouse, okay, I would do it like that. So like that. I 13 00:00:58,770 --> 00:01:04,350 can point that So, among all the lines the landscape of that sector, which covers a 14 00:01:04,350 --> 00:01:09,810 broader mass range, and as you can see, this cannot be covered by a single 15 00:01:09,810 --> 00:01:14,730 experiment. So that is really worldwide theoretical and experimental effort trying 16 00:01:14,730 --> 00:01:18,900 to combine different approaches and different techniques to try to really put 17 00:01:18,930 --> 00:01:26,340 all the information together. But among all the broden, a landscaper, any 64 is 18 00:01:26,340 --> 00:01:33,000 basically on the mid gv region and the world is trying to look for is the time to 19 00:01:33,000 --> 00:01:37,470 probe the models whether that sector on the standard model they are the uncoupled 20 00:01:37,470 --> 00:01:43,020 through kinetic mixing, and the mediator of these forces is carried by a new 21 00:01:43,020 --> 00:01:48,990 massive vector boson call that photo Why are we interested in them? ebgp range is 22 00:01:48,990 --> 00:01:52,830 because we have certain experimental anomalies such as the video you made or 23 00:01:52,830 --> 00:01:58,290 the anomalous new magnetic moments, which can be explained through the existence of 24 00:01:58,290 --> 00:02:04,080 these that sectors with these cards. other candidates in this energy range. This is a 25 00:02:04,080 --> 00:02:09,360 bit what is our target and how we do this. So, which is the technique that we we try 26 00:02:09,360 --> 00:02:15,240 to do. So we are an experiment using what is called an active dump. So, this is 27 00:02:15,240 --> 00:02:21,240 quite simple, what we have is an initial high energy electron beam which is going 28 00:02:21,240 --> 00:02:26,610 to collide with a target with a gamble. And they're what we expect this to produce 29 00:02:26,640 --> 00:02:32,910 through Brunstrom, our bossom candidate which then depending on its mass will 30 00:02:32,910 --> 00:02:37,140 decay basically. So, the kickbacks to combine all the particles that we can 31 00:02:37,140 --> 00:02:42,600 measure in our detector, and this will be the signature or if the mass of the photon 32 00:02:42,600 --> 00:02:47,880 is larger than the dark matter particles, what is going to happen is like in the end 33 00:02:47,880 --> 00:02:52,260 with decay invasively and what is our signature in this pediment is just missing 34 00:02:52,260 --> 00:02:52,710 energy. 35 00:02:54,120 --> 00:02:54,870 So, this 36 00:02:54,870 --> 00:02:59,910 is a bit of our work in principle and the what is any 64 so as I mentioned before, 37 00:02:59,910 --> 00:03:05,640 you An experiment at Western SPSS is designed to probe that sector physics. So, 38 00:03:05,640 --> 00:03:09,660 we had quite a small experiment in comparison with galaxies, but even so, we 39 00:03:09,660 --> 00:03:14,850 adapted for disagree cities from 14 institutions and in addition, we are quite 40 00:03:14,850 --> 00:03:20,880 young experiments. So, it was proposed in 2014. And we started taking data in 2016. 41 00:03:21,390 --> 00:03:27,690 So, we have a broader physics program and trying to cover all this kind of data of 42 00:03:27,690 --> 00:03:33,480 that photon Surtees indeed with an electron beam we started in 2016. And we 43 00:03:33,480 --> 00:03:40,050 took data in 2016 17 and 18 in invisible and visible mode, and in 2021 also we are 44 00:03:40,050 --> 00:03:45,750 already approved to continue taking data in electron beam. Moreover, the 45 00:03:46,320 --> 00:03:51,870 collaboration has proposals to do these kind of surgeries, but with a with a 46 00:03:51,870 --> 00:03:57,000 medium beam what also we can address other planets as you can see here, the the 47 00:03:57,000 --> 00:04:02,070 physics program has been input also of the of the European strategy for particle 48 00:04:02,070 --> 00:04:06,540 physics and we are also part of the physics be on collider Gruber accent. So, 49 00:04:06,540 --> 00:04:10,890 this is basically the broad physics program that we have, but my talk is going 50 00:04:10,890 --> 00:04:15,630 to be focus basically on this channel on the excellent team going to understand the 51 00:04:15,630 --> 00:04:21,360 model a particle, which in this case is electron positron. As you can see on the 52 00:04:21,600 --> 00:04:27,090 on the arrow we we perform the searches the first one was in 2017 was a search 53 00:04:27,090 --> 00:04:32,460 combine also to the A prime decay into a plus b minus and then we also took data in 54 00:04:32,460 --> 00:04:38,280 2018. And then we have what we are going to explain are relatively short with a 55 00:04:38,370 --> 00:04:45,990 target combined results from 2017 and 2018. So, why are these entities 56 00:04:45,990 --> 00:04:50,700 intelligent Why are we trying to look for this extra thing which I will present now. 57 00:04:50,880 --> 00:04:56,700 So, that is their autonomy collaboration. Would you report it indeed, and accessed 58 00:04:56,730 --> 00:05:01,530 on the events coming from the deck cetacean of the very unit Awesome. So, 59 00:05:01,530 --> 00:05:06,060 when these nuclei was excited it was emitting an e plus e minus particle and 60 00:05:06,060 --> 00:05:11,640 the the measure the angle dependence of the submission on the on the body mass and 61 00:05:11,640 --> 00:05:18,210 go to realize what the success around 17 me among all the different possibilities 62 00:05:18,210 --> 00:05:23,820 that you can use to to explain the SEC 17. There is a modeller done by you by fingers 63 00:05:23,820 --> 00:05:29,100 you can see in this paper, which assumes like this, this normally can be explained 64 00:05:29,130 --> 00:05:34,800 through the existence of Afro phobic gauge boson with a mass around a digital. So 65 00:05:34,800 --> 00:05:39,300 this particle to the couple newlyweds not universally with the quads, and should 66 00:05:39,300 --> 00:05:43,260 have a coupling to the electrons in the range, which in the end translates in a 67 00:05:43,260 --> 00:05:48,120 lifetime between 10 to the minus 14 and 10 to minus two. And indeed, this kind of 68 00:05:48,120 --> 00:05:52,920 coupling to electrons is exactly what we can try to test in experiments at any 64 69 00:05:52,950 --> 00:05:59,430 when we have a high energy electron beam. So this is a bit the motivation of our 70 00:05:59,430 --> 00:06:06,660 searches And then. So in 2017, we try to look for these kind of both compatible and 71 00:06:06,660 --> 00:06:12,450 how we did this. So what you have to take to keep in mind also is like, in 2017, we 72 00:06:12,450 --> 00:06:17,490 were set up already, they are for invisible charities. So what we tried to 73 00:06:17,490 --> 00:06:22,470 do was to reuse as much as possible I was set up from the invisible surface and try 74 00:06:22,470 --> 00:06:28,260 to other people to do a visual search is to apply a mind spread. So in the end, the 75 00:06:28,260 --> 00:06:33,210 principle is very, very simple. And what we just succeeded was we added another 76 00:06:33,210 --> 00:06:37,860 electromagnetic calorimeter upstream of our detector, which I'm going to give you 77 00:06:39,420 --> 00:06:45,330 a detail in a moment. So, in the end, what we did was here is where we will have our 78 00:06:45,330 --> 00:06:52,020 high energy electron beam and then we add this small, compact target. So how do we 79 00:06:52,020 --> 00:06:57,990 know if we have produced an X 17 so how many 64 works in an auction so very 80 00:06:57,990 --> 00:07:04,560 simple. We have 100 gb left Through from the h2 SPS beam line they are going to 81 00:07:04,560 --> 00:07:10,770 collide with a with a compactor tungsten scintillator calorimeter, which you have 82 00:07:10,770 --> 00:07:16,470 here and is our active target. So they're what we expect this to produce x 17 83 00:07:16,650 --> 00:07:20,790 through grams per hour. If we produce this particle what is going to happen is like 84 00:07:20,790 --> 00:07:28,800 we should have an energy loss of on the energy measure on the W car. If x 17 then 85 00:07:28,800 --> 00:07:33,540 is produced, what is going to happen is like embraceable should decay after the 86 00:07:33,540 --> 00:07:38,340 dump show what we have to guarantee like the case exactly after the lungs after the 87 00:07:38,340 --> 00:07:43,590 dump sorry. So, to reject any particular leak, we have here a veto when we should 88 00:07:43,590 --> 00:07:47,340 not have any activity in case of the X 70 production. 89 00:07:49,140 --> 00:07:53,760 Then the next ingredient is okay once our particle is produced is going to decay 90 00:07:53,790 --> 00:07:59,370 into in our decay region into an E plus a minus b. How do we know that we have 91 00:07:59,370 --> 00:08:03,660 produced Plus the minus pair basically what we placed there are a set of macro 92 00:08:03,660 --> 00:08:11,130 omegas and gems trackers and the plus two scintillator that we have here s three and 93 00:08:11,130 --> 00:08:19,140 s four which should measure the position of two of these. Finally, to be sure that 94 00:08:19,140 --> 00:08:23,760 we can produce the simplest remains, what we have is our electromagnetic calorimeter 95 00:08:23,790 --> 00:08:29,220 that was the one used for the invisible surface, which is, in this case, a lead 96 00:08:29,220 --> 00:08:33,870 scintillator sandwich calorie meter in a six month six month weeks session. And 97 00:08:33,930 --> 00:08:38,970 basically they're all the missing energy that we have lost in the W call should be 98 00:08:39,000 --> 00:08:49,560 proceeded here in case of XML in production. We are producing but we cannot 99 00:08:49,560 --> 00:08:55,440 produce anything else what we have is a huge are the only economy there at the end 100 00:08:55,440 --> 00:09:00,300 of the setup we should measure no energy the position and also a veto here. Really 101 00:09:00,300 --> 00:09:05,880 guarantee like we don't have additional energy energy appreciation data. So this 102 00:09:05,880 --> 00:09:10,650 is basically the working principle of the of the experiment. And then this is the 103 00:09:10,650 --> 00:09:16,980 result from 2017. So basically what we did, which is our even selection, so just 104 00:09:16,980 --> 00:09:21,690 in in three in three key elements is like First of all, we should guarantee that we 105 00:09:21,690 --> 00:09:26,640 have a neutral exceeding the W car, so no activity on the beat the Wi Fi, they will 106 00:09:26,700 --> 00:09:30,180 have to guarantee that we have charged particles into the K volume, so we have to 107 00:09:30,180 --> 00:09:34,710 reduce any black square. So we should see something about rockets, I mean, our 108 00:09:34,710 --> 00:09:39,900 simulators. And finally, we should be sure that we don't have any other than a last 109 00:09:39,900 --> 00:09:45,720 gathering. So basically, we have no activity on the veto and on the relay at 110 00:09:45,720 --> 00:09:50,940 the end of the setup. In the end, the signature of Covenant annex 17 in our 111 00:09:50,940 --> 00:09:55,470 case, will be basically two electromagnetic showers one in the eagle 112 00:09:55,500 --> 00:10:00,450 wanting the W Cal and the total energies to be just the energy of our union. CRP. 113 00:10:00,900 --> 00:10:06,270 So it would block the energy on the Calvert Sudan and Uganda, but you can, 114 00:10:06,540 --> 00:10:13,290 what signal books will be the gray region we have no signal like even says in the in 115 00:10:13,290 --> 00:10:17,670 the 2017 plan indeed we have one compatible with a quality cuts for a 116 00:10:17,670 --> 00:10:21,810 signal but it was out of our signal about three years. And the other point that you 117 00:10:21,810 --> 00:10:25,440 can see here are basically neutral events and we know that they are neutral events 118 00:10:25,440 --> 00:10:31,530 because we don't see any a charged particle indicator. What we can do is when 119 00:10:31,530 --> 00:10:36,480 when we don't we have open our signal bowls, which are no events, basically what 120 00:10:36,480 --> 00:10:42,180 we define is the region in the region in epsilon, which is the coupling to this to 121 00:10:42,180 --> 00:10:49,470 this dark boson particle and the mass of the X 17. So, if x 17 comes from these 122 00:10:49,500 --> 00:10:55,020 proto phobic origin with a particle of mass 17 mV which can explain them and you 123 00:10:55,020 --> 00:10:59,400 know, normally the mass and the coupling should be in the region. So basically the 124 00:10:59,400 --> 00:11:04,620 message is specs and we should cover the region in epsilon. And basically this is 125 00:11:04,620 --> 00:11:11,520 the limit from any 64 using 2017 data compared also with predictions from other 126 00:11:11,550 --> 00:11:17,100 experiment. So in 2017 when we bought our result, what we did was say okay, let's 127 00:11:17,100 --> 00:11:22,410 try to optimize our setup to cover the remaining parameter space. So basically, 128 00:11:22,410 --> 00:11:27,090 what we have to do to put us in context is to go to larger companies, which means 129 00:11:27,120 --> 00:11:28,530 short lifetime particle 130 00:11:29,820 --> 00:11:35,040 in order to improve our service on the region. Basically, what we did was several 131 00:11:35,040 --> 00:11:40,080 improvements. So first of all, we change the beam energy from 100 to 150 Db to 132 00:11:40,080 --> 00:11:45,630 really boost eco Dec 17 production outside the UK. Then we had a short interval you 133 00:11:45,630 --> 00:11:52,410 can to prove better a shorter lifetime video. And then we add also a female veto 134 00:11:52,410 --> 00:11:57,180 just after w can to be to minimize the probability that excellence indicates 135 00:11:57,840 --> 00:12:02,610 moreover to improve our our Background suppression, what we did was to install a 136 00:12:02,610 --> 00:12:06,750 vacuum pipe. And in addition, thanks a lot, we allowed to the distance between 137 00:12:06,750 --> 00:12:12,300 the eagle, a and the Wk. And we had also some trackers. So after all these 138 00:12:12,300 --> 00:12:18,180 improvements, this is our combined resource to use in 2017 and 2018 data. And 139 00:12:18,180 --> 00:12:22,290 one thing that you have to keep in mind is epsilon as a function of the of the math. 140 00:12:22,290 --> 00:12:26,640 So this will be the region, and 2017 is the dashed line. And basically, the 141 00:12:26,640 --> 00:12:32,970 continuous line is improvement. After the 2018 data, we were able to collect a point 142 00:12:32,970 --> 00:12:37,920 fourth into it then electronics on target. And basically thanks to improve on the 143 00:12:37,920 --> 00:12:43,980 setup, we were able to really reach larger values of epsilon because otherwise our 144 00:12:44,460 --> 00:12:48,060 our sensitivity would only increase nobody, luckily with the number of 145 00:12:48,060 --> 00:12:53,310 electrons on that. So you can see here also the two signal box is for 2017 and 146 00:12:53,310 --> 00:12:58,800 2018. As you can see on 2018 basically we'll have only three new tracks because 147 00:12:58,800 --> 00:13:02,670 we improve a lot our back prediction with increase of the distance and also the 148 00:13:02,670 --> 00:13:08,700 installation of the baquba. But this is not all from our side. So what we expect 149 00:13:08,700 --> 00:13:14,310 to do is to continue around in 2021 we were already approved by SM SPS, and 150 00:13:14,310 --> 00:13:19,350 basically what we plan to do is to really explore the remaining parameter space. So, 151 00:13:19,350 --> 00:13:24,810 we will really want to see if this x 17 comes from a can explain the anomaly even 152 00:13:24,810 --> 00:13:30,180 anomaly and try to cover the full parameter space. In addition, so, Tonkin 153 00:13:30,180 --> 00:13:35,700 collaboration has recent also show new results. So, now, there are nuclei similar 154 00:13:35,700 --> 00:13:40,800 to very similar process to what they observe the MRI you know, normally, but in 155 00:13:40,800 --> 00:13:45,390 this case, you see a boom. So, this has also introduced an additional motivation 156 00:13:45,390 --> 00:13:50,610 to have an independent measurement on these kind of anomalies and try to give a 157 00:13:50,610 --> 00:13:56,880 definite answer. So, indeed, which are our plans for 2021. As I mentioned before, we 158 00:13:56,880 --> 00:14:00,960 want to fully cover the parameter space, but what is missing? Bottom is like in 159 00:14:00,960 --> 00:14:05,790 case that we see some signal like events, what we want to do, thanks a lot is to 160 00:14:05,850 --> 00:14:11,700 really measure the embodied mass. So to be able to reconcile the volume bars for the 161 00:14:11,700 --> 00:14:16,170 small coupling, what is the challenge is to be able to measure the angle and to 162 00:14:16,170 --> 00:14:21,360 really measure the position energy of the blast in mind how we expect to do that 163 00:14:21,360 --> 00:14:27,600 very simple, we want to do a more compact calorie meter, but keeping the number of 164 00:14:27,600 --> 00:14:31,140 radiation dense, so we keep our energy solution and our stimulation of the 165 00:14:31,140 --> 00:14:36,420 background. Then what we want to do is to a large vacuum tube where before our decay 166 00:14:36,420 --> 00:14:40,020 region to really minimize the multiple scattering of the of the particles 167 00:14:40,020 --> 00:14:45,630 produce. And finally, as a magnet, which we spent more than two hours, keep in mind 168 00:14:45,660 --> 00:14:50,340 so we can really measure the separation of the two servers with the tragus And in 169 00:14:50,340 --> 00:14:54,990 addition, measure the position on the electromagnetic calorimeter. We thought 170 00:14:54,990 --> 00:14:59,640 this improvements we expect to be able to to see the environment reconstruction of 171 00:14:59,640 --> 00:15:05,730 the past extracting candidate events with a precision of the 2%. I just come to my 172 00:15:05,730 --> 00:15:11,970 summary very quickly. So I hope that they convinced you that that sector centrality 173 00:15:11,970 --> 00:15:17,340 framework and a 6040 is an idea to to try to probe or rule out many candidates out 174 00:15:17,370 --> 00:15:23,850 there is sort of our combined data in 2017 and 2018. With the 8.4 template and target 175 00:15:24,090 --> 00:15:29,340 have been able to probe with Dec 17 hypotheses is planning they will normally 176 00:15:29,370 --> 00:15:35,490 with koplin below 6.8 10 to the minus four and Amaz around 17. And our future 177 00:15:35,490 --> 00:15:40,170 prospect is to cover completely the region and in case of signal like being able to 178 00:15:40,200 --> 00:15:46,140 register the body mass with 2% precision. To do that, we have estimated we need 710 179 00:15:46,140 --> 00:15:51,360 to the 11 electron targets at 100 gV which correspond roughly with three months of 180 00:15:51,360 --> 00:15:55,890 data taking. And then this search also is expected to be bagging on free up to them 181 00:15:55,890 --> 00:15:59,670 to AdWords. So thanks a lot for your attention and if you have questions 182 00:16:01,319 --> 00:16:06,689 Thank you so much Lara for such a nice talk. Do we have a question from the 183 00:16:06,689 --> 00:16:13,859 audience? So I know Katherine has a question. Please go ahead, Katherine. 184 00:16:14,130 --> 00:16:19,020 Hey, yeah, this was a really, really interesting talk. Thank you so much. And 185 00:16:19,020 --> 00:16:25,290 you go back to your slide 19. This nice. You have, I guess my first question here 186 00:16:25,290 --> 00:16:29,460 is in terms of the area you've highlighted as remaining parameter space, it looks as 187 00:16:29,460 --> 00:16:33,450 though quite a bit of that is within an exclusion curve for na 48 that you've 188 00:16:33,450 --> 00:16:38,910 drawn on there. Is that yeah, that's relevant to this model as well. So it 189 00:16:38,910 --> 00:16:41,820 would seem that maybe their parameter space is actually just a little bit 190 00:16:41,820 --> 00:16:43,350 between any 40 year limit, 191 00:16:43,380 --> 00:16:47,190 yes, or resale because of the bump that they did their model. Yes. But indeed, 192 00:16:47,190 --> 00:16:51,090 they by meter spacing, really between any 48 down there. Yeah. This is basically 193 00:16:51,090 --> 00:16:51,840 what you want to cover. 194 00:16:51,870 --> 00:16:56,280 Yeah. Fantastic. My other question is about the interpretation that you're 195 00:16:56,280 --> 00:17:02,310 using. I'm not so familiar with this. So I'm not sure how much overlap there is 196 00:17:02,310 --> 00:17:08,490 between possible models that could give you the excess autonomy as observed and 197 00:17:09,330 --> 00:17:13,530 the model that you are models that you would be sensitive to. So, are there are 198 00:17:13,530 --> 00:17:19,500 there any sort of situations that would mean that you wouldn't be sensitive to the 199 00:17:19,500 --> 00:17:23,070 same processes or is this pretty conclusive? 200 00:17:23,940 --> 00:17:29,010 So, in principle, what we are what we can cover is basically they the regions where 201 00:17:29,010 --> 00:17:33,270 we can go with the full region associated with explanation coming from this 202 00:17:33,300 --> 00:17:37,350 protocol, because planation but also there are other models as we pointed out that 203 00:17:37,350 --> 00:17:42,780 can explain the anomaly of the of the upset by atomic collaboration with other 204 00:17:42,780 --> 00:17:48,210 kinds of particles have also a model so vector axial particles and indeed our idea 205 00:17:48,390 --> 00:17:54,120 is also try to explore other other kinds of models in the in the next in the next 206 00:17:54,120 --> 00:17:57,660 search. Fantastic. Thanks. Welcome. 207 00:18:00,000 --> 00:18:06,180 I also have a question on this light. So is there any other experiments that are 208 00:18:06,180 --> 00:18:13,470 also sensitive to this region or so to some of these uncover face to face? Yes, 209 00:18:13,500 --> 00:18:16,620 or some of the other face space that is uncover. 210 00:18:17,849 --> 00:18:22,079 So yeah, in principle, so these limits also, for example, the measurement of 211 00:18:22,079 --> 00:18:26,939 alpha on the T minus two is going to get down the skirt. So it's going to explore 212 00:18:26,939 --> 00:18:32,549 some part but for the moment for this particular region a find my where, well, I 213 00:18:32,549 --> 00:18:39,089 think are the most sensitive to this. But I'm not 100% sure I know that they from 214 00:18:39,089 --> 00:18:43,319 the minute to with that grade of the new alpha measurements, we are going to have 215 00:18:43,319 --> 00:18:45,269 more constraint there and to really consider 216 00:18:48,150 --> 00:18:50,280 Okay, thank you so much. And again, this 217 00:18:50,280 --> 00:18:55,260 is all based on explanation of these. Yeah, of this protocol become more than 218 00:18:55,320 --> 00:18:56,610 Okay, another movie 219 00:18:59,640 --> 00:19:05,040 okay. Thank you so much louder. So we'll go to the discussion part of our session 220 00:19:05,040 --> 00:19:10,620 then. And if you give me a minute, I will start projecting some slides.