Federico Leo Redi: Everyone.
Louie Dartmoor Corpe: Okay, so I think probably were more or less ready to start so, as I said, welcome to the latest installment of the longest possible workshop it's a great pleasure to.
Louie Dartmoor Corpe: See all of you here, virtually again, and so in this initial section, we will begin with an introduction and the welcome from James and then we'll have two talks before.
Louie Dartmoor Corpe: Taking a short coffee break, where we will discuss how the landscape of lps has changed, basically, since we started having these workshops approximately six years ago.
Louie Dartmoor Corpe: First, from the theory perspective and then also from the experimental perspective and just one housekeeping announcements, while two housekeeping announcements, first of all.
Louie Dartmoor Corpe: We are recording the sessions, so we will to see them afterwards appearing on the indigo but just just be aware that this is being recorded and, secondly, that will be doing workshop photo immediately after i've used to first first talks so about quarter past three.
Louie Dartmoor Corpe: Central European time, so please do stick around and.
Louie Dartmoor Corpe: Be prepared to turn on turn on your camera so you can be captured in the in the workshop photo.
Louie Dartmoor Corpe: Okay, so I think without any further ado, we should hand over to James he was going to give us a quick introduction welcome.
Louie Dartmoor Corpe: James Please go ahead and share your screen when you're ready.
Louie Dartmoor Corpe: hi everybody.
James Beacham: Good to see here, let me verify that my.
James Beacham: screen sharing is going to work for a moment.
James Beacham: That should work, you should be able to see it yeah.
Louie Dartmoor Corpe: We do perfect.
James Beacham: Then in principle by hit the play it should work.
James Beacham: everything works.
Louie Dartmoor Corpe: everything works magically.
James Beacham: cool okay.
James Beacham: Good old technology so yeah Hello everybody and good morning afternoon evening you know night depending on where you are.
James Beacham: on behalf of the organizers i'd like to welcome you to the LP 11 the 11th workshop to long the particle Community initiative.
James Beacham: For many of you, of course, this will be not your first LP Community workshop for those of you who are brand new welcome to you.
James Beacham: And i'll provide a very brief history of the initiative to set the stage for the rest of the workshop and it's a really nice workshop we have this time because we're bringing back in.
James Beacham: Brian who has been of course busy with some other things, for the last few iterations of the workshop, but of course it's been a key player, since the beginning of this whole initiative so it's a really nice.
James Beacham: kind of homecoming for him and for a lot of us that have been working on this for a long time it's really nice to have had him back.
James Beacham: And i'm looking forward to seeing what he says to hearing what he says, and so the this long the particle Community initiative, just to keep in mind Oh, I have to click here, I think there we go so to remind you what this is the LP community, this is ll E capital C community.
James Beacham: As an independent grassroots platform to study for the study of beyond the standard model LP signatures around the globe and our website is here, if you want to know more.
James Beacham: And when I say, independent and grassroots I mean that it was and still is a platform that was organized by an ad hoc group of people, both experimentalists and theorists.
James Beacham: Who are acting as independent business, not on behalf of any experiment or institute.
James Beacham: Now, this means that you can actually get involved, we hold workshops and we write white papers in the initiative began at the elysee, of course, but over the six years of its existence had this grown beyond that.
James Beacham: We have an e group here if you'd like to sign up, obviously we don't use it too much, probably for usually for announcements of workshops and things like that, but it can be used for other things if necessary.
James Beacham: And for further detailed discussion that will fit into say a zoom chat here, please go to the matter most channel, we hope to be using that.
James Beacham: Through not hope we will be using that, for the rest of the workshop, so please go there, joining the conversation there, for example, follow up questions from a lot of speakers can be followed up in detail in that in that channel.
James Beacham: And if you're still wondering what if you're here and you're still wondering what a long loop particle is then i'll give you a very brief version because i'm sure Brian and Laura will take care of this much better than I can.
James Beacham: The conflict arises when we consider how we veer off and characterize new particles that could be discovered a colliders which is commonly in terms of the masses and the Cross sections.
James Beacham: it's for higher bsm masses, you need higher ag colliders and for smaller cross sections, you need more data, but if you look at it along another very generic access, you can also characterize the potential new discovery.
James Beacham: In terms of the lifetime or the proper decay length of the new particle and when you do this, you realize that the vast majority of the work of collider experimentalists is spent on this part here over on the left and then way out here, when the particle is stable.
James Beacham: And this means that a discovery could be hiding right there in the middle in the lifetime from fear, so to speak.
James Beacham: And so, even though luckily the mindset of the question i'm about to ask is changing some of you might hear this if you're new to this, you might still ask the question because we're kind of conditioned to think this way for some.
James Beacham: bizarre reason which I hope will go away.
James Beacham: ask this question how well motivated is this, and despite that, like I said, being the wrong question of the wrong way to think about our field, the truth is that the lifetime frontier is trivially and generically well motivated.
James Beacham: Because the standard model itself is filled with long that particles, for example, to use simple date night dimensional analysis, the particles in the standard model should have lifetimes of masters along this kind of.
James Beacham: The tan line here.
James Beacham: But it's something always steps into yield a different lifetime, so I won't take the thunder away from Brian stock but suffice to say that the same principles that result in lps in the standard model can generically apply and bsm theories.
James Beacham: And, of course, this diagram is originally from Brian himself modified by Simon can happen and by nathaniel Craig and I made another modification to.
James Beacham: So what this means, of course, for us experimentalists is this yields the potential presence of lps and.
James Beacham: It means that the potential presence of lps yields a whole host of remarkable remarkable detector signatures that for many years has required unique analysis techniques and at least this whole set of.
James Beacham: very interesting detector signatures that we have to for a long time, have had to apply very.
James Beacham: Atypical types of analysis methods on and so of course they're exhausted discussion is there in the Community White Paper the Bible that we wrote a few years ago.
James Beacham: And I would also add, probably them with this like physics case document takes care of the rest that's not talked about in the White Paper.
James Beacham: And, of course, just to put you know not to find a point out of the searches, of course, have been done since day one of the lsc and also have left but it tevatron those links there go to talks from our first mini workshop, where we had.
James Beacham: People talk about the legacy of lps and lab and also tevatron.
James Beacham: But until about 2016 at the La see they were always kind of considered sort of fringe and they still make up less than 10% of our exotic searches, so to speak, there's links there.
James Beacham: So a few of us if you're if you're years it was decided that this was we wanted to make sure that we're not overlooking these and try to bring these into the central set of our.
James Beacham: types of analysis that we do at the lsc and beyond so basically we just organized a few years ago around this one question.
James Beacham: How we best ensure that we don't miss bsm llp signatures at collider experiments and around any collider experiment around the globe.
James Beacham: And so, as you know, workshops White Paper, etc.
James Beacham: So beyond the elysee, of course, is very important at our ability as a field to discovered bsm physics, is not defined only by the interaction points and be like see.
James Beacham: lots of other experimental projects that search for LP so if it's a bsn particle you produce an experiment as a cto and the centimeter two kilometer range before the case and SDK products hit your detector then.
James Beacham: it's along the particle so this leads to obvious and clear connections among multiple projects around the globe that are complementary to those of the lsc.
James Beacham: that's why you know we've had lots and lots of talks from disparate groups everywhere over the years and key key contributors over the years to our workshops.
James Beacham: And you know, for example, it's crucial that the future projects talk about detector and accelerated designs that maintain sensitive to lps from the beginning.
James Beacham: So, as a result, this LP Community capital C Community workshops have become a kind of regular platform to discuss compare and collaborate on LP searches around the world.
James Beacham: So the message that we're trying to send this that don't overlook the lifetime frontier and, of course, right now is a really key really important been really exciting time for a lot of us because run three is nearly upon us.
James Beacham: We are going to have new data very soon and within the next few months, hopefully start to see some first results, so to speak, from some of this from the dedicated detectors.
James Beacham: Are projects that are looking for lps What that means is for us as a Community, we should think more critically about what's next we talked about this a little bit the last workshop.
James Beacham: Time flew since the last workshop, and here we are these things still apply multiple opportunities to explore the edges of our knowledge.
James Beacham: And detector capabilities for lps on the globe in the future, this might be a good time to propose a series of white papers to follow up on the first that come from the Community.
James Beacham: Of course, this you know, to really emphasize this, this Community thing is the place for new practical ideas and speculative boundary of stretching ideas, this is sort of like a sounding board brainstorming place an idea tossing place.
James Beacham: complimentary to that a couple of years ago, there was this thing that was started or I guess year ago I don't know how long now.
James Beacham: The elysee LP working group, so this is like an lpc proper working group that's focused on the short term needs of the approved LSD experiments only.
James Beacham: And you can sign up for the working group list there and there's actually a discussion that's going to go on this Friday really interesting discussion.
James Beacham: With a key meaty topic for the LSD experiments, but, as you can see, these two initiatives are complimentary right the La la LP Community sort of like.
James Beacham: You know lots of projects and ideas that arise there some can be naturally executed under the lsc working group banner.
James Beacham: Others are better served within the broader help the Community so there's the take home message there's plenty big splurge and there's many tools that we have with which to explore so One last word I know i'm going to go along here, I always did, that the the.
James Beacham: The emphasis on Community here for a workshop so community is open to all we pride ourselves on being very informal and very.
James Beacham: inclusive so by being here and participating you're already a member of this Community so welcome.
James Beacham: or workshops or informal and collaboration centered and discussion is of the highest priority so Community means collaboration and collaboration to me means respect.
James Beacham: And so to all the Community Members if you're wondering, yes, you should ask that question you absolutely should and you should make a suggestion you don't have to worry about someone thinking, your question is done it's a great questions don't worry about it.
James Beacham: To all the session chairs remember to give ample space in the discussion periods for those who haven't had a chance to talk yet give a little bit of a you know kind of.
James Beacham: silent time to allow people to to speak up.
James Beacham: And remember that we are radically inclusive and also radically anti harassment so we're here to find new physics.
James Beacham: Both science and society suffer when ideas and thoughts aren't heard because someone feels threatened unwelcome or marginalized it was applies whether we're meeting virtually.
James Beacham: Virtually as now or in person and just you know harassment itself is antithetical to the intention of this workshop, we are endeavoring to create a positive welcoming space and we've always done so in the past, we will continue to do so, the future.
James Beacham: So I put this here I think most of the organizing committee members have had a chance to weigh in on this, so at the moment LP 12 is planned to be 31st October before November.
James Beacham: We do have a little placeholder website there as well, so put that on your calendar also know that maybe somebody will come up with the reason that has to be changed, but probably not.
James Beacham: So put that down now and we will look forward to seeing you there but that's you know premature because we're just starting this works up so again LP 11 and if you squint you can actually write it, you know.
James Beacham: You can write it like pipe the pipe pipe, which means that norm P so there's a lot of fun things you can do with the title of this workshop but LP 11.
James Beacham: The goal of this workshop is really two charts chart of course for the future of the lifetime frontier and you're doing it right now so welcome and i'll pass it back to Louis.
Louie Dartmoor Corpe: Right brilliant Thank you this introduction James very nice intro and our I think probably we have time for a couple of questions and gifts are only on the intro.
Louie Dartmoor Corpe: slides If not, then.
Louie Dartmoor Corpe: I think we can move directly into the into these reviews books to start off the session, so please, if you are, if you have any urgent questions for James you can you can go ahead and raise your hand or type in the matter most as well.
Louie Dartmoor Corpe: In that case, James I think will hand over to our next speaker who is, of course, Brian Thank you James and really great to have you back and we Okay, you have 25 minutes and I will let you know when you got five minutes and one minute left so i'll hand over to you, thank you very much.
Brian Shuve (he/him): Great thanks so much for inviting me to give the talk and i'm excited to be with you, virtually.
Brian Shuve (he/him): I was given the problem that we should talk about how the longest particle landscape has changed in six years and, obviously, the.
Brian Shuve (he/him): sort of you know first Community workshops and organization kind of on a broad level as a really significant milestone, but.
Brian Shuve (he/him): sort of hard to always use that as exactly the starting point so i'm going to be a little bit more general in terms of some of the discussions that will have.
Brian Shuve (he/him): And, as always, you know when you have 25 minutes to give a talk that supposed to be a retrospective you know, things are necessarily going to be brushed under the rug or be presented in a way that.
Brian Shuve (he/him): might reflect how we look at it now, but maybe it's not how it was at the time, so of course you know, forgive me if I there any oversight, but i'll try and hopefully give you a picture of where else how i've seen some things go.
Brian Shuve (he/him): Okay, so, first of all, as James mentioned in his introduction and give a helpful and a very first look at what long with particles are longer particles are, of course, something that traveled long enough that we can tell, and so.
Brian Shuve (he/him): That depends on our technology, and of course lovely particles of in the thing for a long time, ranging from you know studies of standard model particles here, you have the production of a tie on.
Brian Shuve (he/him): which you know travel some distance get stopped to keep you on which probably some distance got stopped.
Brian Shuve (he/him): And then that to kids into a positron which can be detected by you know it's the the momentum and properties can be inferred from, for instance, the magnetic fields similarly long the particles and Center model.
Brian Shuve (he/him): are used all the time, for instance in bj tagging where we can use the long lifetime, the dms on to identify.
Brian Shuve (he/him): jets where you have had run the travel some significant distance from the primary just vertex, and this can be inferred from the fact that the tracks originating from the secondary vertex don't point back towards the primary vertex but they went back in some different direction.
Brian Shuve (he/him): And the resolution is, of course, now the 10 microns level, for instance heavier flavor jet tagging so as our technology has improved so to can our capabilities, depending on what the detector is, we can.
Brian Shuve (he/him): Count different things as long lived or prompt and i'm not going to give a comprehensive overview in terms of why.
Brian Shuve (he/him): You can how you can get Long live particle showing up in every possible way, but in standard model, the main way that you've got long with particles is because of ratios of mass hire us that the mediator.
Brian Shuve (he/him): of many cases the w goes on, and if you have a pie on irby mess on the mass of that part was much less than a w at that leads to every week, for us, which can be too long lifetimes that break that naive expectation.
Brian Shuve (he/him): So this is a plot that James showed or version of it.
Brian Shuve (he/him): And it, it shows the selection of particles and the standard model spanning a bunch of different mass and lifetime ranges so of course this point out that nature already does a pretty good job of spanning a huge range of faith based in terms of.
Brian Shuve (he/him): masses and lifetimes and if there's also interest or the blank areas Okay, because these are regions where there are, in principle, know Center model background, so there might be instrumentation backgrounds, but the challenges in terms of.
Brian Shuve (he/him): triggering and reconstruction that at least in terms of your use of all backgrounds.
Brian Shuve (he/him): That you potentially have an open field where you can look for longer particles and, of course, this includes at heavier masses were above the Amazon model, all of the particles are very short lived at the Center model.
Brian Shuve (he/him): But also, you know another massive lifetime.
Brian Shuve (he/him): And of course long the particles in terms of DSM has been around for a long time as well, so, for example here is, you know very early.
Brian Shuve (he/him): Paper looking for axons and electron beam dump experiment where you're relying on the lifetime of the particle to exit the dumping and decay downstream inside of your detector.
Brian Shuve (he/him): In the 90s, there was the increasing realization that certain manifestations of supersymmetry.
Brian Shuve (he/him): lead to long live particles so in the axon case, of course, this is occurring because if you have small masses and also small couplings which can give license rights to very small.
Brian Shuve (he/him): lifetimes The case of supersymmetry you can have scenarios, where you have, for example, we know or he's you know, states that are the.
Brian Shuve (he/him): mls P and Ls lstm This gives rise to, for instance, then the now familiar disappearing track signature, but many of these ideas were first discussed in the late 90s.
Brian Shuve (he/him): And of course the lab experiments, you know Allah and 1997 how to search for healthy stable charged particles producing electron positron annihilation.
Brian Shuve (he/him): delphia had a search for Tuesday particles with style and LSD and gravity know SP, ranging from you know decay somewhere in detector plus you know, in the stable have the range, so this is really a continuation of.
Brian Shuve (he/him): These efforts that of course date back from the origins and Center model, but you know go way back in terms of.
Brian Shuve (he/him): bsm citrix and smell.
Brian Shuve (he/him): More immediately there was kind of an acceleration of efforts worth one with particles in the early to mid 2010 I guess you'd call that decade.
Brian Shuve (he/him): which was initiated in part because of.
Brian Shuve (he/him): The successful operation of the elysee and a lot of really interesting and important early results, but, of course, was also building on the early work of pioneers people like.
Brian Shuve (he/him): matt sassa who have been talking about long with particles for very, very long time and pointing out all of the interesting ways, along with part of this could be manifesting in the sector.
Brian Shuve (he/him): And some of the ones that i've put that immediately preceded the the sort of official first working group of this Community, as well as the you know efforts towards a White Paper, where some workshops at umass amherst looking for a long with bsm particles.
Brian Shuve (he/him): Of course, important one, six years ago ellison long like particle mini workshop at CERN and workshop at kitt called experimental challenges for the llc run to where maybe in reflection of something that James pointed out.
Brian Shuve (he/him): This was an eight week program to have the weeks were devoted to exotica and that part of one week with devoted to long live particles it's kind of indicates that fraction of Community face face that was pointing that way.
Brian Shuve (he/him): But already by the time of these meetings, there was kind of a confluence of.
Brian Shuve (he/him): understanding that these were really important signatures and that we needed Community efforts like White Paper is to bring together threads that increasingly more and more people were.
Brian Shuve (he/him): In some cases, discovering for themselves and realizing that Oh, maybe people were talking about this for a long time or coming up with new examples and that we needed a comprehensive Community forum for that.
Brian Shuve (he/him): So, in terms of the rest of my talk, there are four things that i'll briefly touch on in terms of.
Brian Shuve (he/him): How we might look at the evolution of long with articles and recent years, one is in terms of the motivation and one with part of the models that people are considering and their place in kind of bsm canon of what you might be looking for.
Brian Shuve (he/him): Another is the coverage of long the particle searches and the reinterpretation, in other words, given searches that are being done there's always going to be more theory papers and experimental analysis, because it's.
Brian Shuve (he/him): cheap and easy, relatively speaking, to write a theory paper So how do we make sure that we can apply experimental results that are existing to other scenarios and.
Brian Shuve (he/him): i'll talk about the dedicated lt experiments and the role that theorists have played in those and seeing them develop and come to fruition and then finally challenging signatures, where we think there are significant gaps, both in terms of that and now.
Brian Shuve (he/him): So again, forgive me if some of these things a little bit provocative but i've labeled lps of loopholes and from that and i'm always going to be a little bit nebulous about exactly when.
Brian Shuve (he/him): Then was but pretty quickly into the running of the llc it became apparent that promptly decaying our parody conserving week scale supersymmetry which for many years was kind of the main standard of the field.
Brian Shuve (he/him): was coming under increasing constraints and that, of course, led to a lot of hand wringing about the nature of naturalness and its role in guiding theory development but.
Brian Shuve (he/him): There was sort of a progression as people looked for the loopholes to the searches so First there was the realization that wow.
Brian Shuve (he/him): You know all of the searches are looking for light flavor jetsons and maybe we should be looking for kind of.
Brian Shuve (he/him): Like third generation couple supersymmetry then when that didn't leave any.
Brian Shuve (he/him): discovery well, maybe it's because of this assumption of our parody conservation, we have our parody violation of course you don't have missing energy signatures that points in different direction.
Brian Shuve (he/him): But what was realized was that another major loophole was if you had chocolate particles and so that.
Brian Shuve (he/him): If it's not being reconstructed correct, we are selected and thrown away, then you could have actually a lot of it, so this includes.
Brian Shuve (he/him): manifestations and supersymmetry that are split or mini split where you have had the scholars and so your some of your lighter particles are decaying through off shelf stuff that displays vertices.
Brian Shuve (he/him): DJ mediation is something that it has been recognized for a long time, with the point out, since the 90s that disappeared.
Brian Shuve (he/him): into person metrics and scenarios and then also in our parody violation, because you have these extra couplings that we don't know the size of you can fairly easily dial down the coupling and make whatever your would be Ls p.
Brian Shuve (he/him): decay and potentially at a displays protect so actually some of you know, our favorites theories and for some of us still important theories contain long with particles kind of hiding them depending on your life can be obscured by what spectra you happen to be looking at.
Brian Shuve (he/him): a really important developments in the mid 2000s was the articulation of this notion of hidden valley and especially.
Brian Shuve (he/him): showing that if you have confining hidden sectors, you can get really rich dynamics that can mimic the standard model or gift things that are very different from standard model, depending on what the confining sector looks like.
Brian Shuve (he/him): And in some sense this kind of blows open the door to all the kinds of signatures that you can possibly imagine Okay, and that is.
Brian Shuve (he/him): In a lot of the earlier work in hidden values, the goal was not necessary to solve a specific problem, but to point out that it's quite easy to have me physics that.
Brian Shuve (he/him): can look like very different from the kinds of physics, that people were looking at already, and so this opens the door to very kinds of long the particles.
Brian Shuve (he/him): Similarly, people were looking at long with particles like hiding the higgs boson like maybe the higgs boson was they are in the Left data or that have a trend data or the early LDC data.
Brian Shuve (he/him): But it wasn't seeing the because of the higgs boson was predominantly decaying into stuff.
Brian Shuve (he/him): Like some kids and sector, states that decay into dark photons and missing momentum and so you've got these lists of lifetime Jackson, you can be hiding them in the fact that you have these displays colonnaded safe that people aren't specifically looking for.
Brian Shuve (he/him): And while they're worse, you know, there was a description of UV models, some of these scenarios at the challenge here is that.
Brian Shuve (he/him): It becomes such a wide range of parameters that we should be looking for signatures looking for that can be a little bit hard to organize signatures compared to say around supersymmetry.
Brian Shuve (he/him): I won't go into a ton of detail because i've looked in there is a lot of talks in this workshop that are going to be touching on all of these different scenarios, so I won't.
Brian Shuve (he/him): belabor the point here, but I would say that a major turning points seems to be that.
Brian Shuve (he/him): As people moved away from some of the more canonical uniform the car parody conserving susie model, it was realized that actually got.
Brian Shuve (he/him): Long with particles and all sorts of DSM physics and that the longest particles are popping out an asked for, and that was really my own entree to the field and it seemed like, no matter which.
Brian Shuve (he/him): problem I was working on whether it was neutrino masses dark matter barrier genesis you just get log with particles that are coming out of your theory.
Brian Shuve (he/him): And so, as we now know you know, there are a lot of models that exhibit hidden sector confinement with dark amazon's include Baltic the training scenario and the neutral natural miss ideas with error sector is.
Brian Shuve (he/him): PC the axons where you play certain games to try and allow it to be heavier.
Brian Shuve (he/him): can show up as long with particles of course supersymmetry, as I mentioned, but dark matter models in elastic dark matter of reason dark matter co scattering dark matter.
Brian Shuve (he/him): And, have you neutral leptons so new MSM and various implementations of the seesaw mechanism dark cases and our photons models of barrier genesis where you again can.
Brian Shuve (he/him): motivate short long lifetimes from cosmological consideration that accent like particles.
Brian Shuve (he/him): And so I would say that, in terms of the year, you community, if you look at head ch probably a substantial fraction of paper is have long with particles and it's not because there's we pause it's because that's genuinely what the UV dynamics, is telling us.
Brian Shuve (he/him): All and, furthermore, those loopholes are clothing and so.
Brian Shuve (he/him): There have been so many really spectacular searches and developments that.
Brian Shuve (he/him): For instance, have no results have shown that Okay, well, we can't always just hide and so, for instance, you know few years ago there were these wonderful plots that were made, for instance, this is an apple by atlas with there are parody can rpc rpc.
Brian Shuve (he/him): document, which shows glue no constraints over the entire range of lifetimes and, as you can see, ranging from very long, very short, there is no war.
Brian Shuve (he/him): And at that time you had to we had to live above to TV and so, if you have theories that necessitates strong dynamics somewhere.
Brian Shuve (he/him): Like we know is there stops, then those loopholes are closing However, there are still some gaps in lifetime searches so i'm showing here paper from.
Brian Shuve (he/him): Some very genesis work that i've been doing, where you get particles that look a lot like puns and even here, we kind of had to be a little bit vague about where in the lifetime playing the prompt searches give out Oh, thank you.
Brian Shuve (he/him): Because there's not necessarily the same type of information that's given so maybe there's still a loophole here, but there certainly don't exist, the same ones that we had before.
Brian Shuve (he/him): So i'll then move on to model coverage and reinterpretation.
Brian Shuve (he/him): So i'm showing up here a plot taken from an atlas analysis and 2011 which shows a presentation of an early supersymmetry results and what some of the younger people might never have seen before, which is a plot and i'm super constraint.
Brian Shuve (he/him): plane and one of the reasons why i'm showing this is that, even as late as this point that there was no simplified model interpretation, this was the only result that was shown in this paper.
Brian Shuve (he/him): And, and that gives us a sense that, in the Grand scheme of things, how recently there was this pivot where it's simplified models.
Brian Shuve (he/him): And in the same year, this wonderful and very extensive document came out with many contributions from Members of the Community, but I gotten to a point that was made, if you look at the.
Brian Shuve (he/him): range of pages devoted to exotica there's like one to two pages you'll see that single page covers things like a weird jeff's.
Brian Shuve (he/him): Okay, and you know we look at one of the paragraphs they won't read it out, but displays the bird this is from a resonance and essentially the entirety of displays vertex searches.
Brian Shuve (he/him): In terms of simplified models is contained within this paragraph, this is not a knock on these individuals, it goes to show that, because there was so much work to be done long the particles were kind of shunted to a later problem that needed to be tackled.
Brian Shuve (he/him): And it was very unclear whether you could take results of along with particle search say from model, a and apply them to model be so.
Brian Shuve (he/him): An early example of interest was whether searches for displays digests that reconstructed a single particle could applied, for instance, along with particles became three jets.
Brian Shuve (he/him): And you know again to illustrate this paper from 2013 you have things where you say.
Brian Shuve (he/him): You know, unfortunately, other important factors that obfuscate the relative efficiency of this search and This again is not a criticism it's just that was the feeling of the time, the Community the theorists don't have the tools to be able to tell whether the searches applied or not.
Brian Shuve (he/him): I think it was pretty significant as theorists and again it was kind of a convergent evolution thing, where there were three or four groups that all kind of did this, at the same time.
Brian Shuve (he/him): Where we were like what did we actually try and simulate this and take into a conference and sector effects kind of we got it to work.
Brian Shuve (he/him): And we found that, for certain examples, the experiments had given enough information so, for instance in that exact case work I did with nano C and around the same time john new and Brock treaty.
Brian Shuve (he/him): had similar investigations of whether you know, read the particle decades could be constrained by the digest searches and we showed that they definitely could and we even got similar results with our independent searches.
Brian Shuve (he/him): But the information could be really hard to come by because if this was you know the experiments were still of course developing all these techniques on.
Brian Shuve (he/him): For the first time, or at least in the first implementation of the llc and theorists didn't actually know what we needed, so there was kind of a back and forth about this.
Brian Shuve (he/him): Now you know when I looked at the databases for longer particle searches and allison cms more of them that not have data links.
Brian Shuve (he/him): And these have data links can include very granular information as a function of the phase space, you know the mass of the truth vert X number of tracks, that the cage angular information so on.
Brian Shuve (he/him): And one of the major out sections of the llc along with particles White Paper the James mentioned contain suggestions and examples of real world use of.
Brian Shuve (he/him): You know how when theorists tried to do this mapping what are issues that they ran into and that there's a real back and forth between the theory and experiment continues to do this we're even seeing that packages like delphia.
Brian Shuve (he/him): and
Brian Shuve (he/him): Actually don't know how to pronounce modeled as models that but you know the hackers using simplified models to constrain.
Brian Shuve (he/him): You, the physics are including long with particles, I think we have to acknowledge the big as long as particles necessarily live at the frontier of.
Brian Shuve (he/him): Experimental information or what the detectors can do we're always going to be a Community where we're going to need to be trying things out and seeing whether theorists can accurately do it, and having a robust conversation.
Brian Shuve (he/him): Third there's been this explosion in terms of dedicated llp experiments, and this has been said tongue and cheek that i've heard that you know nowadays every theorists has an experiment, and I think that this is true.
Brian Shuve (he/him): This has led, in part because in the 2000s there was sort of this renaissance of theorists proposing and collaborate with experiments proposing and even being like spokespeople.
Brian Shuve (he/him): of small scale experiments for hidden sectors and then you know, the first dedicated Long live particle detector at the IFC metal already began in 2010 and the last decade or so there's been this kind of blossoming of.
Brian Shuve (he/him): new ideas, many of which were either originated by theorists are done a very close collaboration.
Brian Shuve (he/him): Proposing looking for long with particles using dedicated detector is, I think that this is illustrated it just how much theorists have become.
Brian Shuve (he/him): You know i'm always an integral to the efforts, but now on on the nitty gritty level of thinking through backgrounds and you know what's feasible for entirely new experiments.
Brian Shuve (he/him): And we're already seeing success in these dedicated detectors, for instance of silicon had a demonstrator Ryan, which put new constraints and leading constraints on.
Brian Shuve (he/him): charged particles in some parts that they space fazer which has been funded and and was running in a test mode was able to detect the first tentative neutrino scattering events at the elysee so there's new physics being done already, with these spirits.
Brian Shuve (he/him): Finally, challenging signatures where where we then and now and.
Brian Shuve (he/him): This list is a crude summary of where a lot of the gaps existed that again being slightly the egg but i'm hydroponically decaying long with particles, especially at low mass and shorter lifetime singing we produce long with particles for searches that relied on Paris.
Brian Shuve (he/him): Even something electronic or in my particular case because, could you have challenging time passing the restrictions if, for instance, you have low masses like below 20 or 32 GB.
Brian Shuve (he/him): Slightly displaced leptons are displaced leptons not originating from just lights vertices displaced TAOs photon I multiple cities confining good and sectors and quirky signatures and actually went back through some notes open the katie the workshop Andy Hoffman I.
Brian Shuve (he/him): Work convener is of the longest particles group and we were supposed to write a White Paper which we didn't because it was too big, of a task to.
Brian Shuve (he/him): kind of combining with these larger efforts.
Brian Shuve (he/him): But when I looked at the Google Doc from our notes of the discussion, the gaps that were identified in this 2016 workshop and that had been articulated for years.
Brian Shuve (he/him): by many people before are very similar to the gaps of the 2019 Oh, he along with particles White Paper which indicates the challenge of covering many of these signatures.
Brian Shuve (he/him): i'll just show a few recent developments where, for instance searches have been pushing to lower masses in terms of hedonic decay is along with particles and higgs.
Brian Shuve (he/him): Because, for instance, use of associated objects like Z ah trigger i'm blocked on to see that allow you to go to New face face in terms of lifetime and coupling, and this is complemented, for instance by searches like cpu where the trigger is less of an issue, but you have smaller acceptance.
Brian Shuve (he/him): letter tonic decay there's been progress on both cms and atlas towards doing powerful new searches.
Brian Shuve (he/him): And there, there were some earlier searches on cms that we're doing this as well, where you're looking at leptons they're not forming a common vertex.
Brian Shuve (he/him): But now more flavor combinations are produced, which allows us to put strong constraints on slept and slept time like signatures.
Brian Shuve (he/him): And there's also in the case of electronic decay is moving to lower and lower masses using things like data scouting that allows to go into Facebook, that would never allow an event to be fully triggered.
Brian Shuve (he/him): photon decays using similar strategies like Z plus H H to came to lps suffocated photons was mad.
Brian Shuve (he/him): and similar This allows us to go to lower masses of the particles to pay the photonic 30 gv that those you could never trigger on those photons directly, you can trigger on Z.
Brian Shuve (he/him): and heavy neutral leptons so low mass displace vertices that came to electron plus not even energetic enough to be jets but had runs and you can get sensitivity to your higher nature La Paz as low as three GB.
Brian Shuve (he/him): And remaining of course of extreme importance but dark showers and this whole kind of new frontier of.
Brian Shuve (he/him): High multiplicity along with particles and Chris cms had first search for emerging jets that came out a few years ago i'm looking at heavy state, so that the trigger wasn't necessarily a problem.
Brian Shuve (he/him): But showing that you could put constraints, using the internal structure looking for high numbers of a high impact parameter trap.
Brian Shuve (he/him): And there's been a significant amount of work, recently, so I want to draw your attention to this snowmass report.
Brian Shuve (he/him): which gives really extensive progress in this direction that was started already, and along with particles White Paper.
Brian Shuve (he/him): That provides benchmarks and i'm also models limitations of the current approaches that really we're now at the point where these things can start being more directly implemented and facing the hurdles to really expand searches here.
Brian Shuve (he/him): So you know to be very crude about classifying these things i'd say that in this top category.
Brian Shuve (he/him): I wouldn't say that they're gaping loopholes and gaps and that really there's always more face to face, you can explore, but there are some really powerful searches that are.
Brian Shuve (he/him): getting into the gaps for these ones down here this little areas where there could be really wide open scenarios and in many of these cases triggers remain a challenge, but there are lots of ideas for so, for instance.
Brian Shuve (he/him): You know, of course, along with particles White Paper, but also this interesting document from the Community on using triggers for triggered on Long live particles.
Brian Shuve (he/him): And finally I won't say much about this, but first we're doing this to.
Brian Shuve (he/him): discover, something we should always expect the unexpected and 3.3 Sigma global significance is not a discovery, but it is very cool to see along with particle search with the dot flight up along with signal.
Brian Shuve (he/him): better than the background, and so we should be prepared for finding all sorts of really exciting things.
Brian Shuve (he/him): So to summarize we've really accomplished a lot and grown and changed over the past six to 10 years but that's really a continuation of an evolution that's gone back decades.
Brian Shuve (he/him): But some things have never changed, which is that llp searches are challenging exciting.
Brian Shuve (he/him): they're quite creative and bold ideas and they inspire the development of a collaborative impactful community that it's been really meaningful to be a part of, so thank you and i'm happy to take any questions sorry for going a minute or two over.
Louie Dartmoor Corpe: Thank you so much it's really, really nice overview of where we come come from and kind of where we're headed as well, so yeah, this is a very nice talk, we have time for a few questions as well, I can see that we have a question a hand raised from Richard, so please go ahead, Richard.
Louie Dartmoor Corpe: hi.
Richard Ruiz: Can you hear me.
Louie Dartmoor Corpe: Okay, great.
Richard Ruiz: hi Brian it's been a while.
Richard Ruiz: I enjoyed this talk is a nice to see kind of this big survey this big history of it that it particularly, I want to focus on this.
Richard Ruiz: The last couple of sides where you're talking about what are the current are hurdles for the llp community, and particularly the these little red points that you had maybe this is on slide 26 I believe.
Richard Ruiz: yeah so for these red points, can you say specifically if these are analyses on the theory side that you that you think need to be done, or on the experimental side.
Richard Ruiz: or motivation for, for example, specifically displaced towns are you hoping that what is the gap per se is this in the theory in literature is is experimental searches or motivated models, can you say that on the different breakpoints fish.
Brian Shuve (he/him): Sure that's a great question and I guess, I would say, both in the sense that.
Brian Shuve (he/him): You know there's motivation for experimental us to look for things where there is broad Community interest, and I would say that.
Brian Shuve (he/him): You know okay there's probably interest in high multiplicity is but that's a really, really hard to do both in terms of capturing theory and experiment, and so I think that really.
Brian Shuve (he/him): explains kind of the the slower progress there, but of course there is progress that's happening, and so this is more, I think, just that we're on a trajectory towards doing that, but that that is a lot of the searches actually have to be.
Brian Shuve (he/him): realized and made public and theory developments megan but their ideas about what needs to be done let's say, for instance, in the case of towers.
Brian Shuve (he/him): You know if the towels are energetic enough, then they decay to leptons and you can so, for instance, of these.
Brian Shuve (he/him): searches here, you can rely on let panic decades of towers and because you're looking at high mass and that's fine that starts becoming less fine when the the.
Brian Shuve (he/him): Massive along with particles in the 10s of GB say where the electrons become too soft to pass the trigger and acceptance.
Brian Shuve (he/him): And you can potentially do better with hedonic towers, but there's really not much that's done I.
Brian Shuve (he/him): don't think really in theory literature there's probably a few papers but that's something that I think could be explored of fleshed out more.
Brian Shuve (he/him): Similar in the photons there are some papers that have.
Brian Shuve (he/him): looked at, for instance in elastic dark matter or photon jets or things like this, I think that this here really experimentally it's a very challenging thing to do, because the thresholds are high.
Brian Shuve (he/him): And if you don't have a lot of net or in the case of higgs production.
Brian Shuve (he/him): You can trigger on a Z, but if you don't have that, then it becomes challenging to do so, I think we're seeing progress or through the courts are just very, very difficult to do.
Brian Shuve (he/him): So I think they are just more work in general on the theory view to be flushed out before we can really expect her experimental his colleagues to do that.
Brian Shuve (he/him): But having a chat maybe during the break about that to me during the rest of the workshop.
Richard Ruiz: That answer my question I might write you on the side, but thank you.
Louie Dartmoor Corpe: yeah really nice, we can always continue or so and mass most discussion we have time we have time for one more question I think before we move in those hundreds from prep so please go ahead.
Prabhat Solanki: hi Brian very nice overview.
Prabhat Solanki: So I had one question, so how we get close the gap for the new mass had run into case.
Brian Shuve (he/him): We.
Brian Shuve (he/him): close the gap.
Brian Shuve (he/him): But you know I think we need to distinguish between a gap where literally anything could be there and we just have no constraints and hedonic decay, is where it's like okay.
Brian Shuve (he/him): we're now probing at the percent level, for instance of higgs to case the hadron no longer electrons I didn't show because it may be that that search strategies, a little bit more established.
Brian Shuve (he/him): They can go to sub percent and now sub point 1%.
Brian Shuve (he/him): If the decay is further out in the detector because of being able to trigger on the case in the H calorie one spectrometer.
Brian Shuve (he/him): So here, I would say, like yes they're gonna be a lot of theories that are living down here but it's not like we haven't looked at.
Brian Shuve (he/him): In terms of challenges the trigger maybe we can do somewhat better but it's it's not like oh there's this whole unexplored face to face or something like.
Brian Shuve (he/him): Non pointing or delayed photons without met, I think that in many cases there's just not anything.
Brian Shuve (he/him): And so, then you could have something that even though it's like you know 30% branching practices or whatever the maximum is consistent with limits.
Brian Shuve (he/him): That could be there, so that drove that a little bit, but of course this is really, really well motivated and so this isn't to say we shouldn't be devoting a lot of effort to that.
Prabhat Solanki: Okay, thank you.
Louie Dartmoor Corpe: Okay.
Brian Shuve (he/him): Okay well thanks again.
Louie Dartmoor Corpe: thanks again for this.
Louie Dartmoor Corpe: really great talk and now we will hand over so i'm going to hand over chairing to Margaret and we all go to the next week.
Louie Dartmoor Corpe: Or at least released I think i'm here with Monica yes.
Margaret Lutz: I can see your screen, but I.
Margaret Lutz: can't see any slight that's very nice background.
Laura Jeanty: Oh OK, I was waiting for you to if you wanted to say something in the.
Laura Jeanty: trenches hi.
Margaret Lutz: Laura Dante is going to be giving.
Margaret Lutz: A talk as well on the landscape, but from the experimental perspective So yes, do you want to go there you go if you only get started.
Laura Jeanty: hi.
Laura Jeanty: Good morning, good afternoon and, potentially, good evening.
Laura Jeanty: And so i'm carrying on from that very nice talk that Brian gave and i'll be looking more at the experimental perspective.
Laura Jeanty: So we tried hard to not cover the same stuff, so I think we've mostly succeeded in that.
Laura Jeanty: So the last six years, as we were targeted with from the experimental perspective happens to overlap very well with the analysis that comes out from run to.
Laura Jeanty: So my talk so somewhat focuses on what we've learned and innovated from run to I will be mostly covering atlas and cms and I won't be covering the dedicated detectors as these have been covered by Brian and will be covered extensively in that dedicated session in this workshop.
Laura Jeanty: To my slides there we go.
Laura Jeanty: So first starting at someone an obvious place but it's worth stating so run to from experimental side has seen an extensive exploration of.
Laura Jeanty: ll fees LP face face, so we have covered a large amount of unknown territory and that shapes very much the territory that we look forward to investigating the future.
Laura Jeanty: So i'm going to start with a brief look at the experimental phase space that we have covered in to benchmark models and i'm going to talk about the experimental challenges and innovations that we've developed in exploring that face based in these models and other models.
Laura Jeanty: So the two benchmarks that will be looking at his first will be.
Laura Jeanty: higgs portal, which is very important portals that we recognize the importance after run one where the higgs to case too.
Laura Jeanty: Long lived scale which then the case for me hands and also be looking at a much heavier example which is long with cleaners.
Laura Jeanty: For both of these we gained huge sensitivity and run to partly due to the increase energy data sets that the light she gave us.
Laura Jeanty: But I want to take a moment just to recognize that that sensitivity gain is not for free, even if it's given to us in some sense for any accelerator.
Laura Jeanty: it's a huge amount of work to analyze the larger data set it's not just returning a crank there's a huge amount of surprises that come up in the data there's a huge amount of complications that come.
Laura Jeanty: With just the data flow of a larger data set and as scientists, we also can't help ourselves from innovating so when we do an analysis we actually tend to improve things.
Laura Jeanty: So, even just when we say just again due to energy data set is actually a huge amount of work from the experimental side.
Laura Jeanty: Nonetheless, there's been a lot of innovation in P searches and that has enabled us to push.
Laura Jeanty: In many directions so we've been pushing toward both shorter and longer lifetime, as each of those has their respective challenges.
Laura Jeanty: we've been expanding our sensitivity to lighter lps, which is also challenging for reasons that Brian mentioned due to trigger for example and back.
Laura Jeanty: we've been pushing deeper into cross section and branching ratios and we've been trying to close gaps in coverage, with a variety of approaches, including new techniques new signatures and reinterpretations of other searches that have sensitivity.
Laura Jeanty: And finally we've been reaching sensitivity to significantly higher masses.
Laura Jeanty: So, to start with the the higgs lps benchmark, so this is the picture in 2015 roughly at the time of the first LP Community workshop and.
Laura Jeanty: What the data told us from run one, so you can see here at our most sensitive point and about see tower one meter.
Laura Jeanty: We were reaching to about the 1% branching ratio hicks and if we jump to 2022 to where we are now note that the axes on these summary plots tend to change.
Laura Jeanty: we've actually reached the personal level, so we've had a huge increase here in the scale and with that the the sensitivity, but I want to point out a few other.
Laura Jeanty: Things that we've improved and the summary plot so we've been pushing toward longer and shorter lifetimes.
Laura Jeanty: Here, this is required to get sensitivity at the lower lifetimes required a dedicated machine learning technique to.
Laura Jeanty: be able to discriminate against the standard model background that's there and then at the high lifetime this this point comes from a reinterpretation of the higgs to invisible search.
Laura Jeanty: we've also been extending our sensitivity to lighter lps so that requires both optimizing sensitivity.
Laura Jeanty: Selection rather for those later lps but also new techniques and one of those new techniques that allows us to really cover a wide variety of.
Laura Jeanty: Mass and lifetime ranges is by using different numbers of llp objects in our selection and trying to optimize the complimentary coverage of one versus two versus multiple objects.
Laura Jeanty: And then, finally, just to point out explicitly this impressive game in the depths of our coverage.
Laura Jeanty: To look at a much heavier benchmark, so if we look at along with.
Laura Jeanty: We had sensitivity at the shorter lifetimes.
Laura Jeanty: From a prompt search, but then there was a gap from the displays vertex search, we were up to about 1.5 TV and then kind of intermediate coverage at the at the higher lifetimes from from a number of searches looking for the.
Laura Jeanty: Direct detection of the the long with cleaner if we jumped to 2022 you can see again that the scale of the summary plot has been increased by a TV which roughly covered the.
Laura Jeanty: sensitivity that we've gained in these six or seven years, which is you know quite a significant jump i'm sure the theorists have lots of tell us, but what that corresponds in terms of naturalist arguments.
Laura Jeanty: And so, look at this a little bit more closely as well, so we are closing gaps here.
Laura Jeanty: Not only in jumping to higher masses, but also you'll note here that the prompt to long live scenario is now fully.
Laura Jeanty: fully covered in terms of our sensitivity there and we've also interpreted are longer signatures for the full lifetime range and so we're able to say more clearly what are coverages in the full range here.
Laura Jeanty: And then just again to point out the the enormous gains we've made overall in this entire plot and expanding our sensitivity up to almost to naff TV.
Laura Jeanty: So in the rest of the talk i'm going to be exploring some of the experimental innovations that have we've developed in the last six years.
Laura Jeanty: I won't be covering explicitly existing gaps in our coverage as those will be covered by other talks in the workshop or, as I said, by dedicated detectors.
Laura Jeanty: But i'm going to focus on new techniques we've developed new analyses new challenges, new solutions, and this is not only to show off all the work that we've been doing as a community in the last six years or so, but also because these innovations are examples.
Laura Jeanty: Often, from one or two analyses and they can inspire progress in other analyses and this will will expect to see a lot more of these innovations moving forward with the further analysis over into and with round three.
Laura Jeanty: So I want to start with one of the most important.
Laura Jeanty: considerations and LP searches, which is the detector handles we use so we often use very unusual detector handles and many of these were developed.
Laura Jeanty: and studied and you know in some sense optimize and run one but we've continued exploration and run to, and I expect that will continue to see innovation moving in German three so i've selected just two examples of new uses of the detector.
Laura Jeanty: itself in run to, and so the first is from cms a very nice recent.
Laura Jeanty: analysis in which they're actually using the forward end CAP as a sampling color limiter So this has two advantages, a relative or that give it complimentary coverage to the more traditional displays vertex searches which look for signal similar signals here, so the first is that.
Laura Jeanty: Because you're looking in the end CAP and there's more shielding this actually reduces a lot of the background, and so, if you're looking for a neutral lps decaying you actually can.
Laura Jeanty: can relax the requirement of to displace verse using only required one which has corresponding acceptance gains.
Laura Jeanty: And also because you're using the moon detector as a sampling color emitter you're actually sensitive to the LP energy.
Laura Jeanty: Rather than its mass and this makes the analysis relatively insensitive to the particle mass where when you're looking at a displays for text analysis.
Laura Jeanty: Your sensitivity tends to decrease with smaller mass because the opening angle decreases when you're using it, the energy that that constraint doesn't apply and so here, you can see very nicely that actually this analysis has sensitivity similar sensitivity in terms of.
Laura Jeanty: branching ratio reach for the different nasa's down to seven gv, so this is a really nice innovation in using the detector an innovative way.
Laura Jeanty: Another example from cms is an analysis which, as far as I know, is the first to use jet timing in the ICO explicitly as an analysis handle.
Laura Jeanty: So displays photon analyses have used the email from both atlas and cms but looking for hydroponic decays, this is the first emulation community, and this is possible due to the very precise timing resolution of the Gala.
Laura Jeanty: which allows, as you can see in the bottom left plot here to actually separate very cleanly signal from from background, based on a timing measurement.
Laura Jeanty: This allows the analysis to reduce background to only a few events but routine high signal acceptance, and so this is again a nice compliment to.
Laura Jeanty: The existing displays vertex techniques and I can imagine and anticipate they will continue to see innovation in the timing front using detector timing in innovative ways as a movement around three.
Laura Jeanty: So, generally, we tend to think especially my thinking of display strikes, we tend to think about displays tracks and displays vertices as sort of synonymous.
Laura Jeanty: But run to has seen a pioneering use of displays tracks without a vertex so Brian mentioned this, but it was such a glaring death and it's so satisfying that we filled it the veil will mention it as well, which is the display slept on analysis from.
Laura Jeanty: Both outlets and cms so here, you have to displace leptons but they don't come from a common vertex and so.
Laura Jeanty: The background to displace track would be enormous to a single display track, but if you require a left tonight ID for those displays objects, you can actually get away without.
Laura Jeanty: The advantages of a vertex which includes a mass reconstruction and or just requiring to displays objects which kills your background.
Laura Jeanty: So this this feels important death in signature space at the legacy that was there for a long time, and it allows us to have significant sensitivity, for example, too long live slept on that was completely missing before.
Laura Jeanty: So the number of llp objects that we select in each event is is non trivial it's not just like ordering off of a menu, and we often start with the the low hanging fruit.
Laura Jeanty: Now, the low hanging fruit differs depending on the analysis that you're working with or the object so sometimes the low hanging fruit is one object if you can, if that object.
Laura Jeanty: is really quite distinct from Center model background or if you can easily tighten the object to reject background, but sometimes the low hanging fruit might be two objects prevent or more, if you have significant background and you need more than one unusual object to rejects the background.
Laura Jeanty: So run to has seen the exploration of analyses that really study the relative optimization between one and two or more.
Laura Jeanty: objects in one of it so here i've selected as an example of this, the recent atlas nonprofit photon analysis which and run one on required to nonprofit photons to.
Laura Jeanty: reject background, but in in run to has really developed a very nice analysis, where the optimize over one and to displace objects, in order to cover to gain acceptance and to cover.
Laura Jeanty: Because actually to cover more signatures.
Laura Jeanty: And, in general, if these optimizations are done within analysis, so what analysis has to signal regions, this allows the analysis design to exploit complimentary coverage to design the analysis regions to really be.
Laura Jeanty: As complimentary as possible and also to make sure that they if a combination is envisioned that our second ality is naturally insured so it's really.
Laura Jeanty: It really behooves the team to who's thinking about more than one object to either communicate between teams, or to lay out a path in advance.
Laura Jeanty: it's not only how many objects one has per llp objects one has per event that's interesting it's also the combination of llp objects and.
Laura Jeanty: More standard prompt handles so we've also seen a movement towards combining LP objects with.
Laura Jeanty: Prompt handles which has a number of advantages which I will touch on in the next slide.
Laura Jeanty: So one example of this from atlas has been was an early full run to results looking for a displays for text.
Laura Jeanty: And we want.
Laura Jeanty: And then you and was not explicitly acquired to be displaced, so this analysis was targeting Long live stopped with an art parody violating decay.
Laura Jeanty: So here one of the advantages of adding in a more standard or prompt object is you get an automatic trigger handle.
Laura Jeanty: which can really enhance the acceptance at the trigger level, it also allows the analysis to relax the requirements on the displays vertex in this case, in order to increase acceptance to a signal and that's important if you want to push toward lower mass.
Laura Jeanty: or sometimes towards shorter lifetime.
Laura Jeanty: This adding in in general, adding in various handles increases the sensitivity to diverse set of models.
Laura Jeanty: But, of course, when you add in one handle then you're in some sense losing sensitivity to another model so while you gain sensitivity in a specific model.
Laura Jeanty: You become less general and so the way to really exploit this requires a lot more analyses or a lot more signatures as you optimize each for a particular face face.
Laura Jeanty: And well this in principle, sounds relatively trivial you know Okay, I have displays her texts, let me just add a new on, let me add an electron towel me at cetera etc it's often non trivial to do this with existing data flow patterns, the way that we've set up our data.
Laura Jeanty: Is is not always optimized in advance for non standard objects llp objects and so adding in existing objects can require restructuring the data flow and this can take a long time to propagate.
Laura Jeanty: And, and similarly for analysis tools so there's often a lot of work behind the scenes to get new object combinations possible and one goal moving into and three is to simplify this so that.
Laura Jeanty: it's actually less work for analyses two two combined objects, whether those are LP objects or prompt objects.
Laura Jeanty: Another nice example of combining a kind of traditional llp objects with standard model or prompt objects.
Laura Jeanty: Is in the flavor of the disappearing track analysis so both cms and atlas have in rent to both expanded their disappearing check analysis and also extended it.
Laura Jeanty: into a kind of non traditional scenario where you have a displaced charging or along liturgy note that from the decay of a long from the case of a prompt school, you know, so this is not the canonical the supreme track search, but by combining a disappearing track with.
Laura Jeanty: Extra jet requirements from the prompter care that we know you can actually significantly extend the sensitivity.
Laura Jeanty: To interesting faces in this case to this more complicated.
Laura Jeanty: decay and this has its advantages, so you can actually suppress the background by requiring prompt jets you get an automatic trigger handle which increases your acceptance for this particular model.
Laura Jeanty: It does again, as I said, is non trivial with existing data flow objects, but what's nice about this and I think what we should think about very carefully when we're designing analyses, is that.
Laura Jeanty: These can these more complicated decay chains can actually be very complimentary and their sensitivity with the direct LP production, and so this is illustrated in this plot from atlas on the left.
Laura Jeanty: Where the lower green shaded region is the exclusion from the direct charging know decay and you can see if you were to have that urge you know it would be excluded, and so you can really focus your sensitivity when you're looking for Lino production of charging those.
Laura Jeanty: On the upper half of the spot.
Laura Jeanty: Okay, so another avenue that we've been pushing across the sheet is increasing our sensitivity to short lifetimes this is hard.
Laura Jeanty: Because the background from the standard model is larger and we're but we've been trying to overcome this challenge in a couple of ways, so the first is by.
Laura Jeanty: reinterpreting prompt searches, which have natural sensitivity there, and the second is with dedicated searches for objects with smaller displacements.
Laura Jeanty: So the reinterpretation of searches has taken several forms.
Laura Jeanty: So this is often again more challenging than just running a signal through the existing analysis and particular it requires dedicated treatment of the systematic uncertainties for nonprofit signals.
Laura Jeanty: So this is an example from atlas of a reinterpretation we did have a rpc susie prompt decay, for a long lived Lino which required studying for example jet response as a function of displacement.
Laura Jeanty: Additionally, care is needed to keep the sensitivity for in prompt analyses too long live signals so often sort of standard requirements.
Laura Jeanty: For example, for event cleaning where you cut out jets that look like they're from detector noise that you know most prompt searches don't think twice about these can have.
Laura Jeanty: Somewhat catastrophic effects on the acceptance of long live signals and so, if you want to be able to efficiently well, if you want to be able to reinterpret.
Laura Jeanty: A prompt search and have reasonable coverage, you need to think about.
Laura Jeanty: The lps sometimes when you're designing analysis, and so this can be quite natural, when the LP signal is considered while you're doing the proper research but probably, we should think about how more systematically to make sure we're not excluding sensitivity unduly in our prompt searches.
Laura Jeanty: The second way, we can extend our sensitivity to short lifetimes is by having dedicated searches, which are optimized for those.
Laura Jeanty: And so, this is a nice example from cms have a display protect search that really focused on the difficult region of you know sub millimeter.
Laura Jeanty: displacement and to try to gain sensitivity here really required developing new discriminates in this case topological disagreements about the shape of pair produce displays vertices.
Laura Jeanty: That allowed them to optimize from this regime and gain sensitivity relative to both the prom searches and the displays for tech searches that look at displays versus farther out, and so I think this is kind of inspiring that we can, it is possible to optimize for this regime with dedicated.
Laura Jeanty: signatures and dedicated.
Laura Jeanty: Work to reject the larger standard model background that's there okay thanks for that one I see it now okay.
Laura Jeanty: So machine learning has been a powerful tool that's been.
Laura Jeanty: More fully exploited in prompt searches in run to that and run one and there's also been a lot of development in the LP world which has different challenges and the prompt searches, so I picked out two examples of.
Laura Jeanty: llp searches that use modern machine learning techniques i'll say that here, I think, with LP searches, the challenge is really are one of the challenges is that the simulation does not necessarily model.
Laura Jeanty: Non standard signatures very well, so how you train these is non trivial and how you validate that your machine learning is actually going to be able to find your displace.
Laura Jeanty: or nonprofit signature is also non trivial, so these two examples I picked up handle this problem in two different ways, so this first search from cms uses domain adaptation.
Laura Jeanty: To make the JET classification, or just trying to tag deaths from elpida case to make it in variant with respect to data or simulation.
Laura Jeanty: And you can see, on the left here, the first plot is without domain adaptation comparison and controllers in between data and Monte Carlo that doesn't decrease so well.
Laura Jeanty: which highlights the problem here in training on Monte Carlo but what this domain adaptation, you can see in the bottom things agree much better.
Laura Jeanty: atlas has done.
Laura Jeanty: has tackled this similar problem, but with a slightly different solution so here atlas used an adversarial network to minimize the difference.
Laura Jeanty: In the training between data and Monte Carlo and again, you can see in the left.
Laura Jeanty: The top plot shows what the data Monte Carlo agreement and a conclusion looks like without using the adversarial network and the agreement is really rather horrific.
Laura Jeanty: But when you use the adversary network, you can see it dramatically improves it increases our confidence that this is a tool that can that can work very well, even when you apply it to data.
Laura Jeanty: So, looking at dedicated triggers, this is a very exciting area.
Laura Jeanty: And it's a hot topic for development, I know that there's again a dedicated session in this workshop, so what I wanted to highlight here is that already in run to there's been a lot of work.
Laura Jeanty: In pioneering llp triggers, in particular, for example, topological triggers and the color matter in both atlas and cms tracking hmt from cms and slow a displace new ones.
Laura Jeanty: as well, and so I think we have a lot to learn as a community from the experiences of the triggers that had been pioneered and part of that is that you know designing a trigger is one thing, but ensuring its use an optimization through the full running is a completely other challenge.
Laura Jeanty: So, Brian mentioned data scouting but I did want to mention as well, in addition to new triggers new trigger level analysis is also an important frontier, this was pioneered in run to for long the particle searches by ICP so it's a very nice way to work around trigger limitations.
Laura Jeanty: And to access lower masses by storing limited event information at a higher trigger rate in this case for them, you and pears and this really allowed me to access.
Laura Jeanty: much lower dark photon masses, then they would by just using the then offline trigger eight cms has a similar analysis as well, and this trigger level analysis has been explored for prompt searches as well, but I think there's more potential for it to be explored in the old people.
Laura Jeanty: And i'm going to end with some experimental challenges and some solutions that we've had we found.
Laura Jeanty: So the first is that reconstructing displays tracks, whether those tracks are in the inner detector immune system.
Laura Jeanty: is challenging due to huge component oryx at high pile up, and so this has been an ongoing problem.
Laura Jeanty: But we've been tackling this, at least within atlas with a very large effort to improve track quality This allows us to reconstruct.
Laura Jeanty: tracks with high signal acceptance, but significantly fewer background tracks per event, so this not only reduces the background in each analysis.
Laura Jeanty: But, more importantly, simplifies the data flow when you have fewer displays tracks reconstructed, you can afford to have those events in more places.
Laura Jeanty: And that that's been a lot of work in that list that set up for three, this is a powerful tool that will allow us.
Laura Jeanty: To reduce the threshold for reconstructing displays objects and that in turn will allow us to open up new face face, and also to add a new prompt handles more easily, and so we can expect this to be a really active area as we move into run three.
Laura Jeanty: we've also been innovating on reconstructing new types of objects and so atlas has a nice pub note out, I encourage you to check it out, if you haven't done it on.
Laura Jeanty: A very challenging problem which is reconstructing soft displaced objects for the example here is the soft pion.
Laura Jeanty: In the case of the disappearing track, which is order 100 MTV and so you're looking for 100 MTV displaced track in a sea of pile up.
Laura Jeanty: This trying to reconstruct this works against the flow of what's happening with more standard objects, which is that as pilot increases.
Laura Jeanty: You tend to raise threshold and tighten selection in order to keep event size and background under control and cpu usage under control so trying to reconstruct something that soft and displaced, you know, requires a lot of work to.
Laura Jeanty: To to optimize around the constraints of keeping cpu and event size reasonable, but this has been shown preliminary in atlas as feasible, and so I think this is a nice example of how we can continue to innovate, even in difficult reconstruction areas.
Laura Jeanty: And finally.
Laura Jeanty: I wanted to just mention it's not only pile up that's a problem it's also integrated luminosity can be a challenge.
Laura Jeanty: So another way of saying this is that more data is always your friend, but sometimes a fickle friend.
Laura Jeanty: So, in particular for the inner detector intubated luminosity brings radiation damage which then affects the charge collection, in particular in the pixel detectors.
Laura Jeanty: And this is challenging for tracking in general, but specifically tracking for dx measurements, which require efficient charge collection in those detectors, and so this plot on the right.
Laura Jeanty: you'll hear more about from an on tomorrow or Wednesday.
Laura Jeanty: But is a plot of the GD X from atlas metal detector as a function of integrated lunacy and the fact that it's just going down is due to.
Laura Jeanty: radiation damage, and so this is an intrinsic challenge and there's multiple solutions to this, so the first detector solution is to just turn up the high voltage.
Laura Jeanty: You wanted an experimental perspective, so I made sure I would talk about high voltage at least once in the Doc but only once, but that has its limits.
Laura Jeanty: So an analysis solution which we pioneered in this latest round of the GD X search.
Laura Jeanty: is to actually do data driven modeling data driven modeling of the dx for signal money color and everything else is done for background and therefore you basically say.
Laura Jeanty: I don't care about what this simulation says i'm just going to measure the effects of the radiation damage in data and use that for my data and for my simulation.
Laura Jeanty: But there's also been work, a lot of work in that list on a simulation solution.
Laura Jeanty: Which is to add the effects of radiation damage to the Monte Carlo and that's a very interesting physics problem with lots of physics about silicon detectors and trapping and things, and so, if you're interested in that I encourage you to check out the the paper here.
Laura Jeanty: So, as we look forward on I agree with Brian lps have always been exciting and I think they will continue to be exciting.
Laura Jeanty: And particular run three is a very fertile territory to look for a little piece, we have dedicated detectors coming online, which is very exciting, we have a lot of.
Laura Jeanty: Work on dedicated triggers which will be interesting to follow, there are new analyses, there are also new challenges.
Laura Jeanty: But i'm confident that will continue to innovate, that in ways that will allow us to push deeper into the face face and innovation will be key because the data set itself won't be increasing significantly and so all of these things new triggers and new techniques.
Laura Jeanty: will be important and allowing us to continue to enhance our sensitivity.
Laura Jeanty: I just wanted to say one thing about the plot on the right, because I often hear you know that lps are hot now, and you know there's.
Laura Jeanty: The Community is certainly growing, which is true, but the if you look at the number of papers we've produced as a function of time it's more or less linear and I think this is partly because.
Laura Jeanty: we're doing more complex and sophisticated analyses and so, even though we have more people in the Community, and we have more people per analysis which also takes more time per paper, and so the actual output of papers is slow, so I think this is reflective.
Laura Jeanty: Of the sophistication actually and the development, the innovation that we're doing in these analyses the fact that we have a larger community.
Laura Jeanty: But we're not necessarily putting out more papers is also probably reflective of the fact that the data set Dublin time is increasing, and so we have more time to work with the papers Okay, thank you.
Margaret Lutz: Laura thanks a lot um let's talk on the experimental landscape, yes, with a thing does anyone have any questions for our.
Margaret Lutz: Oh, I see multiple hands, and I think I am hoping that they're ordered I guess the first one is product.
Prabhat Solanki: Type things for the very nice and useful experimental overview, so I had a question regarding elven trigger so is that a possibility of having dedicated llp trigger it elven for cms like we have casual trigger from atlas.
Laura Jeanty: i'm not an expert on cms.
Laura Jeanty: So, if someone from cms would like.
Laura Jeanty: to handle that but I can I can make a guess, which is that you know, in general, I would say atlas and cms tend to have complimentary.
Laura Jeanty: You know, even if the implementation of our detector hardware, is not the same, we tend to have.
Laura Jeanty: A similar.
Laura Jeanty: feasibility, so I would guess, yes, but i'm going to see if someone from cms wants to take that.
Juliette Alimena: And I can say that, yes, we're working on it um but I don't want to spoil anything so stay tuned.
Prabhat Solanki: Thank you.
Margaret Lutz: hey I think the next steps from the cheetah.
Nishita Desai: Thank you very much for this talk, there were a lot of tantalizing slides.
Nishita Desai: So I actually have two very quick questions first was to understand the word handle that you used in the beginning it's the first time i've come across this a lot of new llp handled so if you could explain what that is.
Nishita Desai: And the second one is on slide 25.
Laura Jeanty: Okay, let me see if I can, yes, so handle handle I meant there as a way of not repeating the word object, so when I use handle I meant.
Laura Jeanty: yeah reconstructed.
object.
Nishita Desai: Just conforming in case I make a mistake later yeah so on this slide I was just looking at the red car for the rpc interpretation.
Nishita Desai: And just looking at the daughter expected line, it seems that you might do a pretty good job just looking at exponential decay and counting how many of them.
Nishita Desai: decay within the traditional volume or something like this do you think that's a good strategy for like a like a quick estimate of how things would go.
Laura Jeanty: Yes, and for for reinterpretation of prompts searches.
Laura Jeanty: You there's a couple of things you should be careful of so if you're sure that you're not.
Laura Jeanty: Actually right if you.
Laura Jeanty: If you think about an exponential decay right, even for a very long lifetime they're still there still a lot of your lps that decay, right at the.
Laura Jeanty: origin, so you can you can you know look within the resolution of your prompt objects and just count the number that of your.
Laura Jeanty: Your LP the case that that happened within that resolution from the the primary vertex if you want to extrapolate out beyond that used to be very careful that you haven't that none of your objects.
Laura Jeanty: Reconstruction is placing any bounce so I talked here about the event cleaning, which is one that on atlas at least we found often can really kill nonprofit signals when you try to reject.
jets that look like they're from noise, for example.
Laura Jeanty: But you can also think about left on requirements that that disfavor and nonprofit leptons and things like that, so if you want to go beyond the resolution and the.
Laura Jeanty: decays that happened of your nonprofit signal, right at the origin, then I think you need to make sure that you're not hit by those acceptance effects.
Laura Jeanty: And then, if you want a more sophisticated treatment, you have to think about actually handling the systematic uncertainties which can be significantly different than for prompt signals.
Good Thank you.
Margaret Lutz: Thanks Michigan that I think that you can go ahead.
Matt Strassler: You said something about work that's being done to make combination of objects both longer than standard model easier, can you just say a few words about what kind of work that is.
Laura Jeanty: Let me see if I can remember what I said what what I meant so one thing I didn't say in this talk that I kind of wanted to say, but it didn't really have time.
Laura Jeanty: Was that, in general, this isn't really answering your question but it's sort of related um that you know, there has been a lot of work on both atlas and cms.
Laura Jeanty: To increase the accessibility of our reinterpretation material for along with particles, so we have done a lot of work.
Laura Jeanty: To improve the object that we provide the information that we provide to the general Community okay that's not what I was talking about I can't remember where it was, but what what I was talking about when I talked about combining.
Laura Jeanty: llp and.
Laura Jeanty: Non and prompt handles at least from atlas I can say that, for example, the work that we've done.
Laura Jeanty: To simplify or improve the displays tracking.
Laura Jeanty: reduces significantly the number of non standard tracks, you need to keep for each event, and this makes you know it possible to envision a world in which you can.
Laura Jeanty: put those displays tracks into more data flow events and then you can combine them more easily with standard candles so a lot of it comes down to very kind of experimentally things right of.
Laura Jeanty: The past that you're the paths that you're different reconstruction takes and whether you need to have a separate stream for.
Laura Jeanty: Different types of.
Laura Jeanty: Non standard reconstruction.
Margaret Lutz: hey thanks a lot, not in La as well, of course, and then I think we have maybe a very quick question from Julia before we go and take our workshop photo.
Juliette Alimena: yeah Sorry, I just wanted to actually make two really quick comments, so I think Laura you had said and.
Juliette Alimena: For the display slept on searches, that this was something we hadn't display certain without a common vertex This is something we hadn't done before run to.
Juliette Alimena: And I just wanted to push back on that a little bit so cms actually published a search on this, I think, in prl and where you have displace electronic them, you are not coming from a common vertex.
Laura Jeanty: So I just wanted to make.
Laura Jeanty: You aware of that sorry that's fair no I wasn't aware of that, I simplified a bit so right, so it had been electron and new on.
Laura Jeanty: Exactly and to reduce the background right you had to the to this similar flavors what was what was New Year right is I should have been more clear was the the addition of the electric electronic only one channel.
Juliette Alimena: Absolutely, yes.
Juliette Alimena: with which I did as well beautifully and the other thing that I just wanted to bring up is that something else that I think that it has changed a lot in the last six years or evidence of this change is that in cms at least.
Juliette Alimena: going towards run three there's 100 hertz at the trigger level at at&t level dedicated now too long the particle triggers like new long the particle triggers so I in case.
Juliette Alimena: I noticed that this didn't come up in your in your talk so I just wanted to mention it, because I think it's really evident of how times have changed, and I think it's a really nice thing thanks.
Laura Jeanty: yeah.
Juliette Alimena: I fully agree, thanks for bringing that up.
Margaret Lutz: yeah yeah so much Laura, of course, also via.
Margaret Lutz: For your talks is highlighting what's dangerous about six years.
Margaret Lutz: And thanks to everyone for the question so maybe we can move on to.