Okay, so Hi everyone. My name is Mater Zaretsky. And on behalf of Atlas and CMS,
I would like to give you an overview of the soft Susy searches at Atlas and CMS.
So, as we all know, wide regions of Suzy parameter space have been excluded with
recent Etsy results, and this is putting natural Suzy under extreme pressure. So on
the left here we have a summary exclusion limit for regional neutralino production
by Atlas. And on the right you have just an example the stop production limits from
CMS. So as you heard in the previous two talks, and many of these regions were
covered in the previous two talks by Carlos and mark and highlighted here in
both plots See that there are several crevices of parameter space which are so
uncovered. And this talk focuses on soft Susy searches with very compressed mass
spectrum. So this is where the delta between the initial and final particles is
very small. And I think there's these plots also show and hopefully my
presentation shows that there's a significant effort both at Atlas and CMS
focusing on this region. So, so why self Susie? So natural Suzy requires relatively
light stops extraneous and gluey knows the small mass splittings can reproduce the
correct cosmological Dark Matter abundance and this is via the process of coagulation
of neutrinos and light stops, or charge, dinos and also soft products give access
to compressed electronic Susy models. So even though there are lower cross sections
for electric electrically Kino production with respect to strong production, With
with going lower and pts, we can have access to these models. So light Exynos.
And electric models also provide a window to natural Susy. But you've heard some of
the details and Carlos system already. So, so in these kinds of scenarios where the
mass splitting is very small, there's little available energy. So the final
states are very soft and there's low math. So, as for example, here on the top right
plot, you can see the leptin PT spectrum and the signal for delta m of 10. You can
see how fast how fast it drops. And typically these these these are missed
these regions are missed by classical searches which require high met and or
lepton pts. So there's a lot of inefficiency also for object three
Construction at very low pities and typically visible decay products not as
the acceptance thresholds. So for these types of searches we require low threshold
triggers and accurate reconstruction. However, what most of these searches for
this characteristic of most of these searches is that we require initial state
radiation. So this is typically a clue and dread originating from Parton's. So, this
boosts the signal vertex and the visible decay products become detectable. So, the
typical signature these searches and the very compressed regions is a heartbreaker
is our jet. Therefore, the math is boosted So, there's moderate math and then we
still have soft leptons and or jets. Sunday searches leptons go down to several
jeebies and many analysis actually, but veto B tech threats, which are not
expected which are too soft to be detected. And in terms of I saw some
analysis Try some more sophisticated methods and try to tack the ice or jet. So
for example and all hydronic Susy search, I started jets attack using large radius
capturing fluids undergoing splitting. So now I'd like to give you an overview of
the different searches, sub searches, with a focus on the most recent results. So
starting with self multi leptons, so for self leptons, there are two searches,
their searches an Atlas and CMS, so requiring to self opposites and leptons.
So in Atlas search, they're required to same flavor lepton pairs in two different
channels, one the electronic channel and one with one lepton and one track and
this search has three main signal regions targeting electrode Kynos slept on and vbf
production On the right on the plot on the top right, you can see one of the
discriminating variables they use is the invariant mass of the two leptons. And you
can see that for different for different models, and you can see that it has a
kinematic endpoint.
It has a kinematic edge.
Then for for the suzay search. It's it's quite similar. However, it requires same
or different flavor pairs. And also not only considers electro Kino, but also stop
selections in the signal region building is done in terms of
the environment.
And one interesting point here on the right, is that this search has a dedicated
time one plus ATMs sugar. So So here's the
trigger turn on of this of this particular trigger.
And it's it's used to access lower math regions to increase the sensitive
sensitivity for very small delta AMS. So just a comment that searches a foreign
two, whereas the bottom one is the US in 2016 data. So focusing on Atlas result,
which is my most recent so you've definitely heard about already in the
previous talks as well about the recursive fixer reconstruction. So in terms of
these, these searches, it focuses on it splits the event into an ASR part and a
Suzy part. And the variables that are used are quantifying the ice or recall so the
ratio of Matt and the beauty of the ASR system and also the transverse mass of the
Suzy system. So this is one of one of the variables that's used in the beginning.
Then also it uses the environment is ready I mentioned but as well as transverse mass
and and other discriminating variables. So, S R is this electrical Kino signal
region it has format region and it does bending in the variables that I mentioned
on the on the plot you can see that the red line signifies where the signal region
is above the red line is where where the signal regions are. So, so, the analysis
set set limits on on different models, so, for example charging or neutrino
production So, in terms of the winner Urbino, you can see the top is or the
Atlas the bottom line the CMS results so, excluding up to around and traditional
masses around 250 gV similar for the Higgs see no assumption exploring around to
Hundred GB and comment for the CMS search there's also an interpretation in the hex
you know pm SSM, which you see on the bottom left.
One of the variables that's
that's used very, very commonly is the transverse mass constructed from lead,
leptin, PT and Matt. And this provides a kinematic edge around the mass of the W
boson which is used very frequently in many electronic searches. And an
interesting variable used in the in the Atlas search is transverse mass, which is
essentially transverse mass adapted to the leptons were 111 set hypothesis mass of
the LSP which which sets a kinematic edge. So at the bottom you see a similar plot
with the signal region targeting at slept on the slept on model and you can see
again the division between the Sydney region and here it's been in terms of Also
the r is r which is the recursive tricks of reconstruction. So here are the results
for the slept and production. So here slept and excluded roughly around 250 gb
for the Atlas search and now in terms of multi leptons This is a very new result
which which was also mentioned in Carlos his talk. Here I would like to present you
the optional region, signal region and in the search. So there's this obstacle WC
selection, targeting compress scenarios. So here, the primary discriminants are the
M L L men so it looks for the minimum environments between the three leptons and
there's also kinematic edge present in these in these regions which provide a
discriminating variable. So on the The bottom right you see the limit set by this
the search on the on the Neutrogena neutrino masses. So it goes up to or above
300 gV and in the very compressed region to around 200. So it's complimentary with
the softer lepton results. And also what's interesting here that additionally the
line the blue line represent constraints calculated and The Beano window
calculation Dark Matter scenario where where the relic density is less than or
equal to the observed value. And now moving on to slightly different types of
compressed searches, so compressed vbf. So in the dialects and search one of the
signal region actually is also targeting the BBF production. So here it uses a very
similar rate. of drugs or reconstruction variable but instead of using Asr, it uses
the vbf treads
as the discriminant.
Also, it's it's been in terms of the vbf or vbf. And and the environment mass and
again, you see the split for the between the signal region and come parallel to
this one, but a bit different is the CMS vbf search. So it's a search in the in the
One Laptop and zero laptop region. So, this is even though the models considered
to have several leptons, it's difficult to reconstruction and identify leptons, so
they either veto or require one soft lepton. And so here are the results for
the compress vbf search on the top is vbf the off shoulder B and C will be no
models. So here you have the comparison of the limits. On the bottom you have the
results of the CMS search and the lights slept on the model which which is also
considered by the search. And an interesting fact is that the models go
down to delta of one GB which is just very small. And other searches of self Tao. So
this was already touched upon also and goddesses search so it's first search of a
self to dramatically the cantel. So here the delta m, astound you tree knows less
than or equal to 50 gV. Here also relies on ASR to target this kind of model. The
beauty of the hydronic towel is between 20 and 40, gv and the signal region bending
which you can see on the bottom right plot is done in terms of the empty between the
Met and the anatel. And here the limits are set in terms of charging or neutralino
and and stop production. And here it's here it's assumed for delta and between
the Trojan on neutralino 50 gb and exclusion is around around three below 300
Pv so two universes below 300 gb and now moving to compress stop searches so as you
can see the list is quite long. And here is the face base of the different decay
modes and they're classified in terms of W decay mode and classical searches which
you have already heard about and Mark stock and I'll focus on the compressed
face space. So here you have For Bodhi the case to genome mediated the case and also
time the case which are
of CNC.
So, one thing for the soft searches is that these use of P tagging techniques,
which were also mentioned already. So, there are different algorithms use at CMS
and Atlas. So, at CMS, there's an inclusive vertex Finder. Whereas in Atlas
there's this track base loop with the vertex tiger. But essentially, they do
very similar things. So they they reconstruct jets from tracks and they
indentify also secondary vertices without the presence of a threat. So these were
these searches were covered in marks 30 generation talk, but who the interesting
thing is that here in the very compressed scenario They require Asr, and they use
the SOF p tag and text techniques for very small times. So this is in the sentencing
electronic channel, and there's all hydronic channel, which is very similar,
they also use of p tag but in Atlas search, they also make use of the
recursive tricks are reconstruction. So there is a lot of other searches which I
don't have the time to cover in this talk. There's a for body decay, which was done
in current count and VA. And there's time decay and there's also other results from
the softer leptons and soft and all hydronic channels and Trojan are mediated
okay. So just just quickly about potential improvements or things that already used
but but we should carry on using so we know that the only increased integrated
luminosity is not expected to bring large gains and sensitivity. So on the top right
Here you have, you have a projection of the soft electron with 3000 inverse
Pentagon. So you can see, if you compare it to the existing limits, the gain is
significant, but, I mean, I leave it for everyone to judge themselves.
I really have to stop you because we don't have so much time we only have one. Okay,
then I'll just go to my go to my conclusion slide, which is just for
reference, if that's fine, but just to mention, there are different techniques
use and we could also use the dedicated cross triggers, which were developed, as
we see in bottom plot. And yeah, so So, bottom line, we need to take advantage of
innovative methods to really push to the limits of detection, analysis and theory.
Thank you very much.
Sorry for going over.
That's okay. We have time for one quick question.
So Any questions anyone?
So this is Jen, can I ask? Those are the soft laptop of yes searches for stops for
instance, does the manager search play any role in this plan? I remember the use of a
rose some coverage in an O data about why we don't have it anymore in this new
coverage summary.
I think I mean, the techniques are very similar. But I mean, requiring this this
this hibbity jet, but I cannot say I'm not sure I cannot speak for the analysis team
exactly why, or, or how it translates onto the onto these regions.
I it's for Derek again. You will just have to wait a little bit but it's in the plans
during Turpan demo jet, or well to interpret the updated fuller and to
monitor theme to this kind of
I see Thank you.
Okay, thank you. Do we have any more questions?
All right, so then