Okay, so Hello, everybody. First of all, I would like to thank the organizers for
setting up this online conference. And I hope very much that we will see each other
in person next year in Paris. And then I would like to thank them for giving me the
opportunity to talk about the Higgs as a portal to new physics, and what is the
role that console fits play in this context. So let me see how I am. So Ivan,
first talk, introduce the Standard Model effective theory, then have a talk about
how effective operators change the topics interface before moving on to the global
analysis. I will talk about the effect of effective operators in Higgs power
production, and I'll be finished with a reality check. So with a comparison of
this specific UV complete models, now one of the main goals of the LSE is to search
for new physics. This can be done either in a model dependent way by looking
directly for new particles. As they are predicted, for example, by supersymmetry,
I can be done indirectly in a rather model independent way, by looking for deviations
from the Standard Model couplings. So far, the only new particle that has been
discovered is the Higgs boson. And there's no other direct discovery of new physics
so far. so in this situation, we have to ask ourselves how we can use Higgs Fitz,
or the Higgs sector to access new physics and what is the role that play defeats
play here and what can we learn? Now one way to parameterize our ignorance about
physics beyond the standard model is given by the effective theory approach. It
allows us to smoothly deviate from the standard model by assuming the Standard
Model feed content and Standard Model gauge symmetries. And by assuming yet new
physics appears at some high energy scale. So the Standard Model deviations are then
parametrized by higher dimension operators that are From the Standard Model fields
and the operators they appear as low energy remnants of having new physics that
has been integrated out at the high energy scale. So, this means that the operators
are suppressed by the scale. And the prominent example is the from the theory,
we are integrating out the charge who someone that was 10 unknown leads to an
effective point like 12 fermion coupling. So, effectively labyrinthian is then given
by the standard model the Crimean plus the higher dimension operators that come with
respectively some coefficients that are denoted by C here, surprised by the scale
lambda. Now, if you assume that the Higgs is part of a doublet so that electroweak
symmetry breaking is linearly realized. This means that the leading new physics
effects are described by dimension six operators, so, then their contribution is
suppressed by lambda strength. a different approach is given by the electric IRA like
luck premium. Here electroweak symmetry breaking is nonlinearly realized and the
Higgs is treated as a singlet and this expansion relies on the carrier expansion.
And later I will come back to the question how we can disentangle linear from
nonlinear dynamics. So, here in this talk however, I will mainly concentrate on the
Standard Model effective theory. This is an approach that has been very well
established. So, there are a number of analysis on how to constrain the wisdom
coefficients. And there are also many tools available for fitting for deriving
the Fineman rules for calculating higher order corrections to the observables for
performing basis transformations. Now, these fixing programs of course, need the
experimental input and here we see the fix from the Atlas and CMS experiments to the
couplings and we see that unfortunately this discover takes four so on so far
behaves very standard model like and these recites then fit into the fitting programs
and So, an example I show here plot by the SP to collaboration. So here you see the
68 and 95% confidence level limits on the various effective field theory operators.
Now, let me come to the topics interface. For sure the top Quark is very important
for beyond the Standard Model physics. The reason is that it's the only from your
calculus that in other one you cover coupling to the Higgs boson. So it plays a
privileged role in most ESM scenarios in order to explain electroweak symmetry
breaking and stabilize the weak scale. In weakly coupled models. This is done by
introducing new heavy particles, like for example, the stocks in supersymmetry. And
in strongly interacting models, the Higgs is viewed as composite object where you
have heavy new top partners that appeal. Finally, you have to know very precisely
the topics interaction in order to determine the trialing itself coupling
from Higgs production.
So here now I show you a few processes at the topics interface and I show you a few
sample diagrams. So apart from the top Quark pair production, of course, you have
here the associated production of the Higgs boson with the top Quark. Here, you
have inclusive senior Higgs production, you have six plus check production, and
you have fixed production. And the colored dots show you how they are affected
affected by the higher dimension operators. Of course, there are more
operators than these that I show you here. But I've been wanting to concentrate on
these three operators. And let me explain them in more detail by looking here at
inclusive semantics production. So here you see the diagrams that contribute with
the various operators. So first of all, you have here the common magnetic dipole
operator, it modifies the top to one coupling. Then you have the topics
operator, which modifies the Yuka Captain to the top quarks. And you have to exclude
an operator, which induces upon coupling of the Higgs boson to two clones. And as
you can see from these diagrams, the common magnetic dipole operator and the
top you cover operator, they captured the Higgs boson to the gluons through a top
Quark. Whereas the effective Higgs clone operator induces a cutting a tree level.
So this means that there's a two fold degeneracy in inclusive fix production. On
the one hand, you have a degeneracy between the top your cover operator and
you have and the exclusion operator. On the other hand, you have a degeneracy
between the common magnetic dipole operator and the exclusion operator. So
the question is now how can we resolve this degeneracy? And here now the
distributions come into the game distributions are very important in the
search for new physics because in their high energy case, they are sensitive to
new physics and things are over they allow you to test several operators at one time.
And this is shown in these plots. So, what you see here is the Hicks PT distribution,
and then you vary one of the operators alone. And here you see the PT
distribution when you vary several operators together. And here in the lower
in the lower plots you see the normalization to the standard motivating
and if you have a closer look at these plots, then you see that the change of the
Higgs coupling to the bottom Quark induce a sizable effect at small PT whereas the
point click exclude the interaction leads to a sizable modification at high PT and a
modification of the top to cover coupling leads over approximately two rescaling of
the spectrum. So this shows you that you can disentangle the top yukata operator
from the exclusion operator. However, when you look at the shapes of the top of the
common magnetic Put operator and exclude operator they both So, show similarly,
shapes with how the case. So here you can't use the distribution to distinguish
these operators. However, you can follow a different approach. So, you can combine
several observables that are differently affected by these operators and
disadvantages discussed now. So, you can for example, combine SR x production with
associated production with the top Quark pair antics plus check the production to
resolve the degeneracy and the potential of this approach is shown here. So, what
you see on the left plot is the fit to the exclusion coupling and the fit to the top
you cover coupling. And this fit you get it from the associated production of a
text with the top crop here and from inclusive fixed production. First of all,
what you see here is that there is indeed a degeneracy between the two operators in
single one SR Hicks production. Now this channel see is slightly lifted already by
including the punching ratios into photons and other standard model famous dates. And
then you have defeat from the Higgs associated production with a top Quark
pair, which is orthogonal. So, you see, can you get combine these two observables
to disentangle the two operators. Now, on the right plot, you see the same back now,
here you have a fit to the Higgs clone interaction and to the common magnetic
dipole operator. And again you see that it fits on a single a single fixed production
and associated production they are may not orthogonal but at least they had to
resolve this degeneracy. So, this shows you that the Higgs measurements start to
become sensitive to the common magnetic dipole operator. And this is important
when you go to high luminosity. So, this is shown in these lower plots. They show
the same but here also the Express check production is included. So now this
discussion shows you already that it is important to combine several observables
when you perform fits. In fact dismissed analysis is only modeling basis
independence if you include all relevant operators that describe the observables
that you include in your feet. The problem however, is that you have to deal with a
huge number of operators. Already at dimension six, you have more than 2400 non
redundant operators if you include three generations, this reduces to 59 for one
generation. Still, this is a large number. So this means a lot of it has to do with a
complicated parameter space with many channels and flat directions and local
minima. And this is the reason why a crescent there's no clover single Chinese
feet to all operators. However, you can follow a practical approach here to reduce
the number of operators you can first of all, apply Some symmetry assumptions like
labor and CP conservation, and then you can focus on certain sub sectors. So, like
the hc sector or the topic sector and so on. And then you need those operators that
are relevant for the particles and processes that you consider. And you
assume that the other operators are very constrained from different processes.
However, one has to be careful here, because this assumption is not always
justified. So, you have to investigate on a case by case study to which extent it is
okay to neglect the other operators in order not to draw the wrong conclusions
from the fields. So recently, this method approach has been presented as a novel
approach towards a global analysis. And as a proof of concept, the authors have
considered 34 degrees of freedom from 10 different processes at eight and 13. tv.
They have mostly included top processes, but also the Associated Press action of
the Higgs boson with a top Quark case included. And what you'll see them here on
this plot of a 95% confidence level limits on the 45 degrees of freedom, one spin you
do in the individual fits in red, then in Cray, you have to close the fit and in
violet, you have the comparison with the results from the top bulking pool. And
when you have a closer look at this plot, then you see that in general, the fits
from the individual fits lead to mastering constraints. And this is because you
neglect your cost calculations. Now, of course, this has to be extended to include
also other observers and as Tony told us yesterday, they are working on including
more observables from the electroweak sector and also from the Higgs sector.
Now, let me move on to expand production. expand production is a very important
process because it allows us for the ultimate test of the Higgs mechanism,
because if you are able to measure the training and the heat quality Except
coupling between the standard model are uniquely determined by the mass of the
Higgs boson, then you can use these couplings to reconstruct the x potential
and verify verify experimentally the Higgs mechanism. So the challenger itself
coupling is accessible directly in his car production and aquatic one in principle
into the production. And the main process at the LSE is fluid fusion. However, the
problem with this process is that it leads to a small sickness, so it's perfectly
fine to ban and it suffers on a large QC background. So it's a challenge. So what
you see in these two plots are feeds from the Atlas and CMS collaboration to the
training itself coupling by setting all the other couplings to their standard
motivators. Or I just see, yeah, okay. No, it's okay.
And then you'll see here the combined feed from the Atlas collaboration which limits
the timing of excess coupling to manual five inches. So I've been now focused on
the effect of higher dimension operators on Higgs power production. And for
Standard Model X pair production, I refer you to the talk I said I knocked out
tomorrow afternoon. So now you see here how Higgs production is affected by higher
dimension operators. So let me first mention in the standard model, you have
only these two diagrams that contribute. So you have a triangle loop and quad in
the box though, however, the effective operators they use for other diagrams. So
let's have a look. First of all, you have an overall shift of the couplings. This of
course, you have an outpost, this is awesome, the process is steady I showed
you before. And then you have an operator that shifts the Higgs coupling. You have
the topics operator that changes the Higgs coupling to the top box and induces also
another coupling that is not present in the standard model. So in effective to
Higgs to fermion coupling then you fv exclude operator which needs to appoint
coupling between one or two exposed sons and two clones. And you have two common
magnetic dipole operator that modifies the top clone coupling and induces also this
another coupling here. So now I can tell you about how we can disentangle between
linear and nonlinear dynamics. So in the Standard Model effective theory, there's a
relation between the coupling of SR and two Higgs bosons to two clones. And
there's a relation between the coupling of one and two Higgs bosons and fermions.
However, this relation is not there anymore in nonlinear effective theory. So
you can use dynamics production to pop directly if you have a linear or nonlinear
dynamics of electroweak symmetry breaking. And this shows you also the necessity for
club effects. Because in order to disentangle this, you cannot only look at
SR Hicks production. So you have To look also at processes where there's no expose
on where they are to expose them, let me also mention something else. So, I told
you in the standard model we have only these two diagrams and in fact they both
interfere destructively in the standard model and it becomes clear Of course, when
you include higher this higher dimension operators, this destructive interference
is destroyed. And it becomes also clear that the limits that you will derive on
the training itself coupling depends on the description that you choose, so,
linear or nonlinear
Okay, so, we have all these operators that enter Hicks care production. And the
question is now of course, can we perform fits to the trailing excess coupling by
keeping all the operators at their standard model bagels and ever discussed
this with this plot that I took from a talk by Can you feel your need to so what
you see here is six pair production nominal as to the Standard Model value
when you vary one of the coefficients of these operators and the dashed lines are
the values of the weights and coefficients that have been excluded so far by the
state by the Hicks data from the LLC. And the violet line is the one related to the
variation of the training itself. So, now, here you see the presently best limit on
Excel production and you see indeed at the moment, it is enough to vary only the hit
training accept coupling and to keep the other couplings at their standard mode
values. However, with increasing position, this is not justified anymore, and you
also have to include differential distributions, because they effective
affected differently by the various operators. So, I have shown you here now,
how Hicks power production is affected by the senior Hicks production operators.
Now, we can turn this question around and ask ourselves how Hicks SR Hicks
production is affected by a variation After training and excessive coupling and
a variation of the training, yes excessive coupling of the training and excessive
coupling enters in electrically corrections to the SR Higgs production
processes. So, we can ask now, what are the indirect limits that we can derive on
the training and self coupling from the synthetics production processes? There
have been several courts that have investigated this question. And they found
that in Dec keep these indirect limits can be competitive or at least complimentary
with the directly complex pair production. However, this approach is challenging
because you have to combine several processes with different functional
dependence on the training access coupling, so, you have to perform a global
fit, and you have to include at least nine additional coefficients from SR Hicks
production. Moreover, the dominant effect on SR Hicks production comes from the
leading other operators unless you assume My very specific theory where the only
modifications affect the trainer in the aquatic excessive coupling and not all the
other captains. So, let us have a look at the potential of combining singer and
double Higgs production, this is now shown in this plot. So, here you see a fit to
the try linear excessive coupling including differential observers from
signetics production PCs include and from w x production This is in red and formal
combination which is in pink. And you see when you perform a club effect in
synchronous production, so, when you include the effect of all relevant
operators, then the limits are less stringent than the limit that you obtain
from hitscan production stay SR x production is important because you can
see from this combination here in pink, that SR Hicks production helps you to
resolve the degeneracy that is there at Delta Kappa equal to five So, the next
natural step would be to move on and combine single and double Higgs production
processes and to gradually include all the other element operators other than the
trailing SF coupling. Also do higher order QC corrections have been calculated to
expand production coming from the effective theory operators. And here you
see a resize on this call, they perform a calculation in the electronic IRA. Look
again, you see here the K factor So, the next leading order to the leading or the
cross section, and you see what happens when you vary one of these with some
coefficients of the various operators. And you can see that when you include the full
top Kwok mask dependence, then these k factors show a non uniform behavior. And
you see also that at least for these scenarios here, it varies between about
1.5 and 2.4. So, let me finish with your reality check. This is important because
In the effective theory approach, you assume new physics to be there at a high
energy scale. However, there are many beyond the Standard Model models with
extended tech sectors that predict also like particles. So, in order not to miss
any new physics effects, you have to combine the effective theory approach and
also look at specific UV complete models. And I will discuss this now for a few
models in the context of production. So, here you see that expand production
diagrams that contribute that you get when you look at the supersymmetric theory for
example, the next minimum supersymmetric as a standard model, you see what happens
there. So, first of all, so, this is the production of a standard model like
exposed on paper. First of all you have modified top and bottom you cover
couplings. Then of course, you have modified try linear couplings. You have
new particles that can run around in loop and you have new heavy Higgs boson songs
that can be produced resonantly and then decay into a pair of standard model like
explosives. Another example for most commonly interacting theory is composite
tics. And here you have also effects from New particles in the loops effects from
modifications of the couplings and you have this novel to Higgs to fermion
coupling and all these effects together, they can lead to direct cross sections
that can be considerably larger than in the standard model. And let me show you
two examples. So we perform the scan in the CP violating to extrapolate model and
in the Nemesis m, and he kept only those points that are compatible with the
relevant theoretical and experimental constraints. And he has shown you that the
maximum cross sections that we found so far his care production in the CP
violating tweaks tablet monotype one, we found cross sections as large as 850 10 to
come to be compared to the Standard Model value f. Se ri femtocell endorsing the
type two model you'll still find the core sections that can be the dominant of the
standard model in the nm SSM you are constrained from supersymmetry. So here
your top down to the Standard Model value. However, if you look at the production of
a standard mode like explosive with a lighter non standard mode lackeys awesome,
you can achieve large cross sections. And here in the C two h m one type one, if you
look at the production of lights on a pair of like a non standard mode like exposed
on you can even have huge sections. So, it could even be that we see new physics for
us in the experimental section and not in singing production. Let me finally mention
an interesting thing a double top picks into play that we found. So, we looked
into the CP violating tweaks template model. And here you can have additional
heavy exposed zones that can have large punching ratio in the top quartile and now
when they interfere with each other Back home, then you see here that this leads to
a destructive interference, but these semi exposed sons can of course also decay into
a Higgs boson. And when you interfere this process with the other Higgs production
diagram, so, you do a sickness signal interference, then you can see that this
year the interference is constructive. So, destructive signal backhand interference
in the top called final state can come along with a constructive signal signal
interference in the expect protection. So, this shows you that you should not
underestimate expect protection. So, let me conclude on this very positive note. I
have told you that the F key approach allows us to rather model independent
access new physics This is an approach that has been very well established.
With increasing theoretical and experimental precision. We have to include
higher order corrections This is something I could not talk about here because of the
lack of time by I could talk about that district twice also the inclusion of more
operators in the fit, I told you that if t distributions are very important, because
they are particularly sensitive to new physics, they allow follow the resolution
of lead directions, which also of course, is done by combining several solvers and
they can help several operators at once. Then I told you that if you want to test
if you have a linear nonlinear electroweak symmetry breaking, you have to combine
several processes. So, for example, you look into Excel production where you can
start to disentangle this. And finally, I showed you some confrontation with reality
because this is important as EFT is not sensitive to light resonances. And I have
shown you that in expel production, you can still have side effects so, the future
is private I would say. Let me also mention that I have edited an additional
psychological value find the link to my song boom. I've up there from 630 on so if
you want to have further discussions and now I thank you for your attention,
not my game.
Oh, the floor is open for questions now. Raise your hand
be shy,
it's quite easy you just have one button to push.
So maybe I will break the ice and so on page 24 you discuss some possible
degeneracy, you know with modified coupling to blue on with dipole operators.
So, my question is, how large should the dipole be in order to mimic this contact
interaction to view on I mean the Pacific UV realization where can get so large
dipole operators?
Ah, frankly speaking, I cannot answer this question because here
I'm no expert. Yeah.
And so
no, I don't know. I mean, I know that from the papers that I read that it's important
to include it because indeed, you are sensitive to it. But I mean, he received
he we see some value here we see the typo operator here, at least I mean, it varies
between minus one and one over t v squared. So this gives some hint.
So somehow there is at least one order of magnitude one or two orders of magnitude
between those two kind of operators. Yeah. Yeah.
And also, I would like to edit because I couldn't do it. Talk. It's interesting
because I mean, As I told you, there are also other operators that affect these
maximum measurements. So for example, associated production with a top Quark
pair is also affected by four fermion operators. But you can use these now. You
can constrain them in top Quark production and then use the Hicks measurements to
constrain the common magnetic dipole operator, because you see that you are
starting to get sensitive to it.
Like so there is one question by Michael But before that, I mean, somebody mere
note in the chat that actually is a PDF of your talk is not available due to some
technical problem. So maybe send the link to use Zoom Room, and then we'll put it
into the chat so that everybody can actually
okay delink Yeah,
yeah, there's just an IndyCar problem right now. This is what's happened during
Facebook. It wasn't in there is no evidence if I do it off the box. Yeah.
Okay. I did put it in the check the link.
Yes. So no Michael Stevens a question
just to this issue about the size of these numbers, this really depends on the
convention that you're using for CTG and see 5g. So, this order of magnitude
difference may be due to different extraction or standard model factors, or
none of them. And therefore, when we have to look at the proper normalization of the
coefficients of these operators, to to, to understand the meaning, in particular, the
constraints that come from 50 bar, and as you can see, the constraints from 50 bar
are impossible, the green band and this means that that's the purpose of the green
band
situation
and it's availa t t bo, u
tt pascaline. I don't know okay. And I know the TD Bank constraints are not
visible so sorry, I was confused by physics, but but one partner possible.
Step One has to translate the fits to TT bar production to the to the convention,
it was one of these verses coefficient that are used and these fits. And there's
always the same story that different authors are using different conventions.
Yeah, indeed, I saw this when I prepare to talk and at all you have to be careful
when you interpret this, because several authors, they put the couplings into the
operator several orders, they don't do it and so on.
And this means an order of magnitude difference between the size of these
operators doesn't mean that this is really a difference of the relevance.
Mm hmm.
Giovani wanted to ask something.
Do you when you get closer to the microphone?
Not so much. Okay.
So I was wondering if for these
cases
In principle
changes the interaction between the
Jets
or something of that sort, right?
I mean, there are several combinations that you can perform, of course, I mean,
you can even use six pair production. I have some cloth in the appendix, but it's
true. I mean, I had to focus here on on on a subset, but it's true. There are many
other things that you can do. And you can also use the processes you're talking
about. Yeah, whatever. I mean, in principle, the point is that you need to
have poses that are have a different sensitivity on the operators that you are
looking at.
Thank you. Yeah.
Okay. Any other things?
There's another comment in the chat. From Maria. She's saying that she thinks Those
results using top data on slide 29.
What did she say?
in the chat? She said that the results using the top data on slide 29
Okay, thank you.
Yeah. Good.
Okay, so it's probably time to move on. So let us say, Maggie again.
Thank you.