Can you see that?
Okay, very good.
Now in full screen Yeah,
it's perfect. Thank you.
Okay, good. So thank you first to Alina, for this wonderful segue into my talk,
which was premeditated. And I'd like to just thank the organizers for the
invitation and of course for the opportunity to still carry on with this
with this conference and really would like to compliment them on how nice it's been
and how well organized everything has been so far. So I'd like to tell you a bit
about progress, the status, of course, and progress and some perspectives on the left
and in particular in the quest for for new physics. Okay, so, we find ourselves sort
of 10 years in 10 years since the start of marriage. One, one, and no real clear sign
of new physics so far, of course. And we've just seen that play out lots of very
nice summaries from from the first two talks in this session. And I think it's
fair to say that direct searches have somewhat saturated this this energy
frontier capacity that we're all very much looking forward to, and when we switched
on, see, so unfortunately, I also picked the Atlas summary plot that was not
coordinated. And I probably feel a bit bad about that. But actually, the CMS one is
in the backup of the slides. And this again, just showing that the energy scale
that is being probed broadly by by the experiment. So what can we kind of draw
from this information or at least start to speculate about the bsm? Well, we could
say perhaps it's too weakly coupled. So somehow we're rate limited, and this is
quite optimistic in the sense that we have room for improvement. We can collect more
data still 20 times more data to count, let's not forget. So So this is one
avenue. Another one, of course, is that it's just too exotic. So we haven't really
been looking in the right place yet. And this is also very positive, because it's
just we're really just limited by our own creativity and of course, person power.
And therefore, it's our job as theorists and experimentalists to motivate and
enable these these searches for new and exotic signatures. The last case is when
the SM is too heavy, and therefore is kinematically out of reach from a
Collider. And that's kind of the worst case scenario from the from the direct
search point of view. But of course, this then just moves us into the business of
indirect searches. And so this is, of course, the reminder that direct searches
aren't just the only thing that we're doing with the nhc. In fact, we've really,
it's also worth remembering that we've kind of achieved the number one objective
of this machine, which is, of course, discovering the Higgs and we're really in
the midst of a very huge program of printing. measurements, Standard Model
interactions all the way up to the TV scale. And it's really thanks to the
efforts of all of us as a community internationally at the LSE can also be
used now as a precision machine. And the big question, or at least one of the big
questions is, of course, what's the origin of the electroweak scale. And I think one
of the clear places that one can look is in the interactions among the key players
in this game. So by that, I mean, expose on the electronic age persons in the top.
And I think a very positive statement about this situation that we're in is that
sort of, independently of the outcome of any of direct searches for new physics, a
really big part of the LFC legacy going forward is going to be this big, precise
set of measurements on the interactions that govern these. These guys here is the
sector. And so for the gauge and Higgs part, I want to emphasize that that we
really want to test all the components of the Higgs field in the sense that the
Goldstone modes also kind of mixed together with with the gauge bosons via
and become the longitudinal modes. And this is, I think, a very interesting
avenue to to carry on testing. And on the other side we have, of course, the top
Quark which we know, being most strongly coupled to the Higgs is very special. And
this has strong implications for the SM and of course, on top of the fact that the
LSAT is the top factor in giving us even more reason to to look into this guy. So,
we've already kind of reached this shift of paradigm over the last 10 years from
these direct bump hands, to thinking more about these indirect searches of looking
into tails. And this, of course, connects with the fact that we have reason to
believe that new physics may well be heavy. And I think the language or
framework that really marries these concepts of potentially having new
physics, high energy, but precision measurements is really the Standard Model
EFT or the Smith as I will often refer to it in the rest of this talk. And broadly
speaking, it's a parameter space that encode encodes the parameter space for
BST. interactions between standard law particles.
And in many ways, it's kind of like a version two of the standard model. We kind
of accept then that we have access to just this low energy effective description,
where new physics is somehow integrated out at the highest scale. And the Standard
Model, what we call the standard model is just all the sets of operators that go up
to dimension four canonical dimension four. And then this DFT by denoted by this
schematic sum over here is just this tower of operators of higher mass dimension. The
only rules here are that we work with the building blocks in the standard model. And
that for the smacked itself, we actually assume this linear electroweak symmetry
breaking so the Higgs is a doublet. And of course, we respect the gauge symmetries of
the standard model. And I just wanted to stress here that this is more than just a
parameterization of ignorance. It's quite unlike the so called anomalous couplings,
framework in the sense that it's an order by order normalizable quantum field theory
that just happens to have this finite Energy range denoted by this cut off. And
on top of that, where it possesses this well defined matching procedure that
systematically improvable where one can connect concrete models of new physics as
long as it's heavy to these rules and coefficients of these different operators
here. So one very kind of crucial aspect of looking for the phenomenology of
standard model. EFT is this notion of energy growth. And so, very broadly
speaking, high dimensional operators equate to energy growth. And if you think
about just a generic insertion of some dimension six operators say into here to
to to amplitude, or indeed any kind of amplitude, you expect to get different
types of effects. On the left here denoted by this green box are kind of these
constant effects, which are like shifts that proportional to the square of lambda
squared, and they rescale Standard Model rates. And so that means that rate
measurements, they're going to be in the domain of rate measurements in terms of
constraining these types of effects, and then these are the ones which eventually
will become systematics dominated as a lifetime as the NHD progresses. On the
other hand on the right, these purple ones are the new kinds of effects, which can go
up to a squared in the case of dimension six with respect to the standard model.
And so these are increasingly will increasingly be better and better
constrained by high energy measurements. And we can somehow keep on going to higher
higher energies or finer and finer buildings. And so we can always be in a
limit where we can improve as we collect more velocity. So this is kind of a very
nice, systematically improvable process that we can pursue for improving our
understanding of these high dimensional parameters of the standard model. The
story is slightly complicated by the interference structure of the dimension
six effects with the Standard Model, because of course, in order to get a cross
section, I've got a squares amplitude, and that's going to induce terms of higher
order. So one and under fourth. And in fact, this pattern of energy growth and
different symmetries can end up mixing this naive hierarchy of the spmt
expansion. And this is coupled to the fact that dimensioning operators are generally
not studied in a framework. So, so one has to approach each problem individually, I
think. So the smacked of course is trying as much as it can to be model independent.
And so the only real requirement here is that somehow you'll be assemblages above
the scale of your experiment. On top of that, we don't know a priori which
operators your new physics is going to generate. So it's really bottom up in
nature, and therefore, that really calls for a global approach. And so I would say
the ultimate goal in terms of the left is this complete likelihood of the general
left, which as you well know, contains many, many parameters even at dimension
six. And so of course, we start small and we start with realistic subsets of
measurements and operators, and hopefully exploiting symmetries along the way to
kind of structure the way in which we compartmentalize our parameter space.
I think that the long shutdown, the second long shutdown that we're in right now is
really an opportune time of course, to take stock right? I mean, there are legacy
papers coming out now with a full run to data set, as we've been seeing for the
last few days. And I think a Smith fit is really a fantastic benchmarking and data
preservation exercise that is very worth doing. It kind of takes a step back and
ask the question, where do we stand? how sensitive are we in all these directions?
And also, where would be good to look next, so that there's much progress in
lots of directions. And I think it's very good to have several groups working in
parallel in terms of fits. And I think my prediction is that I expect many, many
fifth papers to be coming out in the next year or so. So let me focus on a couple of
interesting bits of progress in these directions. So the first one I wanted to
mention, starting with the electronic precision observables is this paper, which
came out since the last nacp edition where the full QC D and electroweak corrections
to the Zed and W poll observables were computed and so this is really the first
complete nll left fit result, to my knowledge in the sense that they really do
all the cool the lip corrections possible. With all the dependence on the relevant
operators, and then go and do a little statistical analysis of what the
implications are. So at leading order you have 10 operators in particular basis, the
Vasa basis, and but you're only constrained eight directions, this is a
well known fact. And of course, now these guys have shown that when you go to nll,
that number of operators goes up to 32. Although you also do have to additional
new constraints. But the point is that before leading order was very almost self
contained in the blind directions could quite easily be closed just by adding a
couple of bits of Higgs or dipoles on data, but I didn't allow another fit is
nowhere near self contained. And so one really has to to combine more measurements
to actually be able to make make a precise statement here. And I just show here a
couple of figures just saying that basically the order of the corrections is
something like 20 30% in terms of when you look at critical subset, a closed subset
of operators and the impact of these corrections. So this is very interesting
progress, which hopefully will Progress percolate to the full sector of Smith's
interactions as we go towards the end of the lifetime of the nhc. In terms of the
combined and Higgs electroweak measurements, I picked out this paper,
it's not brand new. But it's a quite a kind of a comprehensive combination of lab
and LLC 112 data, where they use this flavor universal assumption, so no flavor
structure and in different bionic interactions, which is kind of a standard
way to reduce your parameter space. And it also was one of the early ones to include
some differential information for the Higgs in the form of the stage one sex,
simplified template cross section measurements of Higgs production as well
as some IPT divers on stuff. And so here, they just do some nice statistical stuff
where they quantify the impact of adding run to data, you see that you can get some
order one effects there. And on the right of course, you have this naive
interpretation where you invert the constraint and turn it into And energy
scale to kind of have an idea of what types of scales that one might access with
this, of course, depends on the value of c that that makes you But in general, one
can see that TVs are kind of being potentially accessed. But the real reason
I picked this paper actually is because they take a next step where they actually
map to your view models, which I think is very interesting. Here I just show an
example that they took of two dimensional models of some scalar and actually triplet
resonance as well as the vector length or doublet and you can see that you can
really easily map these to UV models. And I think, although fit results are for me
especially interesting and useful in and of themselves, and the real interpretation
starts here. And we don't really have much of an excuse because the CV matching is
almost done for us now, there exists a complete tree level dictionary for all
possible models up to that generate them six operators, and there are many much
progresses is going on in this universal one loop corrective action direction where
one can provide a similar dictionary at one And I think one, one thing that's
worth mentioning is that UV interpretations are concrete models,
they'll usually involve subsets of the full basis to the parameter space isn't
going to be as big. There'll be correlations between the various wisdom
coefficients, etc. So when you look at lively look at the results of the fit, one
should bear in mind that if once you plug a real model in your constraints are
actually likely to be a little bit better. One thing that's important as well is that
you really need to retain the full likelihood enabled in order to be able to
do this in a kind of agile and flexible manner.
The next thing I just wanted to point out quickly is this more recent work, where
actually this flavor assumption was reduced. So it's a quite a similar
exercise to the previous one. But I think it only uses signal strength. But in the
end, the cool thing that they did there was that they didn't say that we have this
live universal assumption and, and so you increase of course, a bit the parameter
space, and they even did quite a nice interpretation in terms of a custodial
vector trip. Hello again, were here, you see that, again, multi TV types of
interactions are potentially being accessed, which is quite promising.
Another thing that I wanted to load them for was that this, that they make the
results in likelihood available publicly available through this smelly tool, which
is a global smash likelihood tool, which can be found here. And I think it's one of
these very important efforts that's going on towards everyone being able to clump
together to go towards this false myth likelihood. Here, I just wanted to flash
some results in the top sector. Again, this is not brand new. But one of the
important advances in this work here is that the studies including analog CCD
effects for the top processes, and so here again, I just do this naive interpretation
here on the scale and you can see that perhaps the order of sensitivity in the
top sector is a little bit weaker on the right and a bit stronger on the left and
there's actually a clear split between the operators that are constrained by Tiki Bar
and single top which are of course To stick through which processes of the LFC
towards the more rare top modes on the right, like ttv, single top, let's see
four top anti TPP. So there's quite a hierarchy of sensitivity in the sector.
And one other interesting thing that was done in this paper was was that they
assess the impact of these quadratic terms that I mentioned in the cross section. And
in fact, you can see that in some cases, the the blue one, which is linear only, so
only one over lambda squared terms, some of the constraints disappear. So you
really see that because some of them are completely dominated by quadratic effects
in some cases, and this is something which needs to be looked at a bit more closely.
And finally, I think I just wanted to mention the experiments because they are
really starting to get into the game and thews e Azzam for this model has really
percolated down quite strongly to the community. And I think this is great.
There are too many results to cover here. And I just wanted to flash some results
for one honorable sort of one Higgs example here, which is stss measurements,
although I do want to give an honorable mention to the top Experiments community
which have been leading the way a lot of the time in this, this method
interpretation. Typically, of course, the experimental results when they do fits,
they'll consider slightly smaller parameters basis, but but on the other
side, they have a better handle on the uncertainties and the correlations etc. So
I think this is a really valuable added information in terms of this ultimate goal
that I keep going on about. So going forward, I think it's worth just saying,
you know, fits aren't really that fun. It's something of a slog in many cases of
creating new data, curating the data that you're going to add in, etc. And there are
lots of gotchas, you've got to be aware of statistical overlap correlations, etc. And
I think it st access are really a perfect kind of controlled evolution towards being
able to combine fully differential data and they're definitely going to be
included in the next generation of fits. Of course, I find that there are very good
compromise in terms of ease of interpretability but also global
sensitivity. When Of course, one caveat Bear in mind there is a, there's some
system model assumptions that go into extracting these numbers. And so I think
it'll be important to keep quantifying To what extent those are actually important.
And another thing, which I think is was good that was done recently was to
actually study the information content in terms of being able to constrain this
math. So in this paper, these guys actually looked at wh, and did compared
the sensitivity to some kind of idealized statistical ideal and and were able to
actually show that by making some kind of slight improvement to the bins, one could
get a bit closer to this perfect information. And so this is a nice sort of
back and forth going on here between the experiments and the phenomenology
community with regards to this stuff. So defined simply cross sections. So if we
just look today and say, what's going on in this map with what we know?
Well, of course, we really want to make the interpretations and say, well, what's
the what's the upshot for real new physics models and of course, this is where the
Model independence of this math disappears. So by construction when you
interpret the result, it's model dependent. There's nothing you can do
about that. And especially so the validity of the EFT the implications on your models
is all a posteriori. So you've got to go away, do your constraints first, then
check what's going on in the model. And so that really inherently depends on the
sensitivity of your measurement and also the energy scale that you used to probe
the interactions. And of course, we don't know what the new physics scale is, it's a
bottom up thing and so on one side, you have the CEO of a lambda, which is
arbitrary dimension for parameter, and on the other you have some coupling of mass
scale new physics. So you cannot you can just imagine that if you make some
constraint on this quantity C of a lambda squared, this would represent itself in
some kind of line in the parameter space between the coupling and the mass. And,
and you can come at it from different ways in terms of what's a valid interpretation.
Well, at some point, your coupling becomes too large and you can't really make
predictions for what the rules will go It's bounded from above. And it's also
bounded from the fact that if you assume a certain value for the mass scale, then you
better not have used data that that was at that energy. So there's a lower bound on
the mass scale. And so you kind of have this line of valid region of parameter
space. So it's quite difficult to make general statements here. But I think it's
fair to say that we're probing TV scale physics. Although there are hierarchies
and sensitivity of various measurements, and of course, as you go to moderate to
strong coupling scenarios upwards along this line, then you're most safe from this
validity worry of being too close to the energy scale of your measure. However, I
think generic noobs I think you're saying I have 45 minutes left. Okay, generic new
physics and loops doesn't look challenging. But concrete models should be
better constrained, as I said. And of course, as we widen our parameter space,
our sensitivity can potentially go down, but we should certainly widen it enough to
test realistic models. So I think that's kind of the next step here. I think that's
why a motivation, the motivation for the next step will really be to combine top
Higgs electric measurements. I think a lot of there's a conspicuous split that has
been between these two sectors up until now, but I think these kinds of results
are really going to be hot off the press very, very shortly. And in fact, there's a
talk on Friday by Peter gala who's you may well give us some some results there. So
yeah, this is really the motivation that if we want to understand the week scale,
we should try and make a swift fit about all the parameters that affect the
particles that are most important in this electric symmetry breaking sector. And in
fact, there are very interesting processes that are being measured like Tth, red top
production, single top plus z four top. All these things are going to be
interesting to combine all together, although it's somewhat unclear to what
extent these two sectors will talk beyond Tth. Although of course, we know that top
measurements are important for things like x production. So I just wanted to flash a
few other interesting results. in various directions, one thing was left in the
PDFs. So can the PDF extraction procedure absorb new physics effects, there's, of
course, lots of data being used to pin these quantities down. And in this work,
they perform a proof of concept using GIS data and including some operators, which
would potentially affect the extraction of those quantities, and showed that indeed,
there is some impact when you either fix the PDFs or do simultaneous extraction of
recoveries in the PDF. And even in some cases, you can actually get a better fit
in the standard model using these four fermion interactions. And there's a
related issue to mention in passing is also alpha SS often is part so PDF
determinations are part of the determination of the strong coupling
parameter. And this is something which hasn't really been discussed in general
for what's the impact of Smith on on the alpha s parameter that we actually use in
all of our calculations. This other one is interesting where they started looking at
combining high energy data with flavor in a kind of coherent way where Even if you
assume that there's no flavor violation in your DFT coefficients, if you put put
loops of W's in there, for example, you start to induce this violation at one
loop. And since those low energy measurements like BDK and mixing are so
sensitive, one can actually get complimentary information. And they found
five new constraint directions when they go from the Smith down to this week
effective theory, which is kind of it's a no energy cousin, down to the flavor
experiments and found that there's really some new information that to be gained.
And I'm personally interested in the impact of top data it's in this direction.
Loop technology has been improving here. They there's been a lot of people some
thinking about what's the impact of particularly top electroweak interactions
in loops, because these are the ones which are sort of not very well measured. And so
there's a body of work here, which is very interesting and finds some competitive
sensitivity. There's a talk tomorrow by two Martini on the titty bar one and so
that's good, too. Competitive sensitivity but on the other side, we start to get
lots more parameter directions that could lead to problems will be marginalized.
Here is a slide about tools. So the technology for these loops is kind of
automated now and there are some interesting results going on in process
dependent calculations and implementations using such as power hag and of course this
this method and Alo two which is an automated framework for Minecraft. And so,
I probably just skip these just to say that we have some preliminary results for
di and try those on and we're going to very very soon have have a paper out on
this and the tool is already public, although it doesn't include the for for
real operators yet but everything else, you know your Smith for the electroweak
symmetry breaking sector is there with the capacity to do process independent reading
or QC calculations. And this is also especially relevant for things like glue
on productions, fusion, so Higgs productions on fusion where of course The
leading order for the standard model this is this is a one loop effect. And so you
know, once you start modifying all these guys, you, it's better to start actually
including the loops once you start to look at, for example x plus jet, where you
start with a IPT region where this infinite top max limit might actually
break down. I wanted to say something about dimension eight, probably I'll just
say, I've just spent 10 seconds on it. Up until now, we just knew how many operators
there were. But very recently, two papers came out on the same day and wrote down
the complete dimensions eight basis and that's 45,000 operators encoded in 1000,
some grudging terms. So this does pave the way for kind of explicit studies. But of
course, we're talking very large numbers here. And I just wanted to also mention
that positivity constraints are also applicable on these dimensional operators,
and that's something which has been evolving quite fast in recent months. The
last thing I wanted to talk about is this idea of how can it be improved with with
increasing statistics So, generically speaking,
time is out.
Okay, just want let me just say one thing, then
high energy we said is something good for looking for this math, but in fact, I just
wanted to point out that high multiplicity is also another way in which we can try
and guarantee energy growth in our swift amplitudes. And so, things like rare
electric top production, with more final states in in conjunction with with weak
bosons, longitudinal in particular are interesting. And also for the Higgs case
where you have operators that modify his signal strings. This also can be tested in
different ways by looking at particularly the longitudinal content of the Higgs
field, longitudinal gauge bosons and lots of processes with more final states that
probe the same operations that affect the Higgs signal strengths, and there are some
Exploratory Studies going on with that. So I think it's worth stayed staying tuned
for those So let me conclude to just say that this method is really truly well
established in the hip community now particularly for the dimension six side.
And we're on the path to really measuring these dimensions, six parameters and
standard model and extending the reach of the LFC. Beyond the nominal energy, and I
hope that I've shown you that the multi TV scale is within reach. And I think the
next step is to start looking at more realistic models. And there's much work to
do, but the tools are available. There's progress in many directions. And this is
going to be a big part of the NFC legacy. And so let's continue to look at high
energy and multiplicity and
and as a run but as a roadmap for the future. So thank you very much.
Thank you very much can
so there's not much time but of course there will be enough for questions. I see
one race and yes mean if you can identify yourself, please go ahead.
Hi. Can you hear me? Yes, I can. Okay. So I'm using from ij. C lab is the new name
of my lab. So I have just a couple of question. And thank you for the very nice
talk. So just before you mentioned the global Fitz, I did not write down the
slide number. You mentioned it interferences, which seemed to make your
life complicated if you could elaborate on that. Yes. Maybe I can ask my second
question. Right. And then later on, in slide 14, you mentioned the interpretation
that you were doing was a naive one. And I was just wondering if this was because you
were making assumptions on the kind of on the values of the couplings that you were
dealing with?
Okay, let me answer the second question first, because it's very easy, the answer
is yes. So, so, you know, naive because the energy scale and the size of the
Wilson coefficients are completely degenerate. So you can't say anything
about the energy scale unless you fix them. We have a couple of so that's model
dependent, you've kind of made the assumption. So it's naive in that sense.
So typically what people do in their mind is that they set a couple into one. And so
that's what this
y axis would correspond to in terms of energy scale, if you if you set the
coupling to one
the question about interference is a little bit more involved. But an important
thing perhaps actually, the the relevant slide is I kind of skipped over it, but
the relevant slide is actually later on. Were here. So even though so basically
putting in an operator into an amputee doesn't necessarily guarantee that it
grows with energy. And that's because it was shown that in general, for example,
for to any kind of scattering, which doesn't involve a longitudinal gauge goes
on. So at least involves one transverse gauge burrs on all of the dimension six
amplitudes do not interfere with the standard model at height in the high
energy limit. So the Masterson so somehow the olicity structures are the kinds of
amplitudes that this method likes to generate and the ones that the standard
Has, they actually don't like to talk to each other. And so oftentimes you find
that, that this interference, where you expect the leading term in this expansion
to occur is actually suppressed by some kind of higher reason. Sometimes it's, you
know, color structure. Sometimes it's the solidity selection. And so it's a bit this
naive expectation that the most dominant effect always comes at one over lambda
squared. And dim six is not always the case, especially at the nhc, where we have
very high energy.
It's very, he said, the absence of interferences is due to the dimension of
the operators that you are doing, not just that, no,
yes. So in this paper, they showed that for all kinds of dem six operators, it
just so happened that if you look at the mathematical sort of the structure of the
amplitude that they generate, in terms of the cities and the particles, it doesn't
match up with the Standard Model once and so somehow it just, it just doesn't like
to interfere just to kind of on first principles grounds in a high energy limit.
But they put it there. Prove that for dimension six to two. Whereas it so that
that's sort of the limit. So you for two to three scatterings. It's a bit different
for dimension eight, it's also a bit different.
Okay, so if I were to take something away the dimension, but also the time the type
of processes which are distinct? Yes.
So so it's a type of process. And indeed, just because one operator doesn't give you
energy growing interference in one scattering doesn't mean that it won't do
it for another one. So you really have to be as broad as possible. And look,
everybody.
Thank you. Thanks.
I don't see any more raise hands. I think that this is a thank you again for this
presentation. And it's very good to see all these tools coming out and also being
more accessible to experimentalists. I would, I would have questions for you, but
then we go too long. So we will Want to thank all the speakers of this session
because this is the last talk of the afternoon and