I’d like to welcome you to this first panel discussion during this year’s Lindau Nobel Laureate Meeting.
My name is Felicitas Pauss, I am an experimental particle physicist at ETH Zurich and I am going to be your moderator.
It’s now my great pleasure to introduce to you our panel members.
Three of them you have heard already this morning during their talks in the morning.
We start with Professor Kajita, followed by Professor David Gross, Professor Carlo Rubbia
and our fourth panel member is not a particle physicist, he will give his talk on Wednesday.
So the subject of today’s panel is Glimpses Beyond the Standard Model which is, of course, a very vast subject.
And there are, I am sure, very many questions associated with that.
We have heard this morning that our standard model of particle physics is a beautiful theory,
extremely well verified by experiments.
And so far the two match very well together.
However, we have also heard that it cannot be our ultimate theory
because it leaves nevertheless some very important fundamental questions open.
For many years experimentalists have been trying to find hints for new physics and their respective experiments, and we all hope,
and also expect, that some of those glimpses and hints for new physics, and eventually discovery, we will have at CERN.
And this is the reason why we have today a direct link to CERN.
Do you hear us at CERN? Can we see them also on the screen?
So we have on the other side in the room at CERN Fabiola Gianotti, she is since this year the Director General of CERN.
And we have next to her three young scientists from ATLAS, LHCb and CMS Experiment:
Jamie Boyd, Daniele del Re, and Mika Vesterinen.
Before we enter our discussion, I would like to recall for those of you who might not know that on July 4th, 2012
we also had such a panel discussion about the subject of particle physics,
just on the day when CERN announced, and made a press conference, about the discovery of the Higgs boson by ATLAS and CMS.
Unfortunately, today there was no press conference at CERN.
You can’t have everything at the same time.
But nevertheless we have this unique opportunity to have this link to CERN.
And we will have, of course, the possibility to ask the Director General and the young scientists
about the latest news we can have from CERN.
Before we start, with the idea to warm up, I will ask our panel members a few questions
and then also pose questions to CERN so they can have some, make some statements.
And then we start the general discussions.
You in the audience, you also are kindly asked to participate, to make a very lively afternoon discussion session.
And we have been entering modern times now also in this Lindau Meeting.
You have the new app on your mobile where you can type in questions.
And by one miracle or another those questions arrive at my desk here next to me and I will read them to you.
So we are today first time doing this.
So think about the questions you want to pose to anybody, either panel or the people at CERN.
Ok, so we start now with the first short introduction, warm up to the subject,
Glimpses Beyond the Standard Model, starting with Carlo Rubbia.
Carlo, I remember very well the time, the beginning of the LHC project,
which you really pushed very hard that it really become a reality.
So, therefore to you as the father of the LHC, I would like to know from you, have you done so far, you experimentalists at CERN,
done everything so far correctly that we are on the right way to “Glimpses Beyond the Standard Model”?
Clearly, we have this very monumental result, which was discussed several times yesterday and today, which is the standard model,
in which effectively you can give a good prediction to all kinds of experimental situations and theory situations.
And the question is, is there any deviation of that standard model at sight?
And if so, how do we find it?
First of all everybody is convinced that the discovery of the Higgs is a very fundamental step forward.
And certainly the Higgs will be a platform in which people will try very hard to see how well the standard model will shape up
after the observations of the Higgs, which is a brand new type of particle, with the scale of particles coming out.
But we all know, we are all convinced that these things, if any, most likely will be very small.
Everybody prepare himself to something like the tiny contribution that the standard model –
of course, this is not necessarily true, I mean nature may decide otherwise.
We have natural philosophers, many of the greatest discoveries came up unprecedented, unprepared by all of us.
But still the point is that it’s most likely the effect of standard model will be small. Now, how small?
Well, I mean the situation is that a few percent may be a good number to get as a reference point to say
whether within the framework of the Higgs particle stories, whatever it was, and therefore we need a substantial accuracy.
Now, the question is will LHC, which now is the real living activity that we have in our hands for now and also the future,
be capable to see the accuracy that we would like to see in order to get ourselves probably this quantity or this magnitude.
Most likely it will not be enough.
We will ask this maybe later.
Let me finish what I have to say. I mean, we have 87 minutes to talk about it.
Now it’s obvious therefore that the question now is whether this effect can be done with the Higgs itself
and all this physics of it, probably require, in my view, another machine.
Let me give you the example W and Z which we already had used at CERN, another important CERN discovery,
like the Higgs was a CERN discovery.
And in that particular case there was a hadron discovery done with W and Z -
and you were there, both of us were there, members of this experiment, younger people.
And then there was the LEP which really did perfect beautiful work of cleaning billions of events etc., etc.
In my view, I would expect that the experimental search for deviation of the standard model might demand
to have a similar situation of a major discovery done at CERN with the hadrons, which is the one I had 2 years ago,
followed by the equivalent of LEP, namely, in my case, a muon collider
which should be able to produce the large number of particles having the Higgs all by itself alone.
Just like the zero, all by itself alone, was the reason for LEP.
I finish at this point, thank you very much.
Thank you very much, Carlo. Turning now to David Gross.
David, I also remember very well your brilliant talks when you talked about the discovery potential of the LHC.
Over many years we were fascinated about the potential of discovery of supersymmetry at the LHC. Today what do you know?
Do you still count that you are going to discover supersymmetry at the LHC?
I certainly hope so. I am going to lose some very big bets if we don’t.
Who knows? I mean the excitement of physics is not knowing what's going to happen.
One has clues. We have clues. Some of them might suggest something like supersymmetry.
For example the discovery by astronomers of a new form of matter.
Most of the matter in the universe is dark matter, which they see gravitationally
but we haven’t been able to produce yet at the LHC or observe underground.
So it’s waiting to be discovered and analysed.
Supersymmetry gives a nice scenario for making such a particle.
That’s one of the clues we have for such speculations.
So we have some clues, not many, but some very important ones.
Dark matter, neutrino masses which hint at another scale of physics.
And then we have the clues that motivate theorists like me:
the completion of our theoretical framework in cooperation of quantum gravity.
The unification of the forces, which is suggested to us by experiment,
by the structure of the forces that we have discovered and understood and their apparent unification at a very high scale.
And the mystery of matter: why do we have quarks and leptons
and their masses, with a strange spectrum which we can’t calculate at all?
And there are mixings which were discussed today at great length.
Those are wonderful features of the world which we’ve measured with precision but don’t understand.
We should, our theory should do better.
So we have all sorts of wonderful speculations, even more important, we have wonderful experimental clues.
But the answer is in nature’s hands.
I can only urge my colleagues who are working so hard at LHC to make sure not to miss the discovery of supersymmetry.
Thank you. Professor Kajita, you have so nicely explained today in your talk
that the standard model with massless neutrinos is incomplete.
We know now neutrinos have a mass.
What other hints would you expect from the neutrino sector to come in the hopefully near future?
Other hints, ok. Well, before going to talk about the other hints in the neutrino sector
I just want to say that the observation of the large mixing angle was kind of unexpected.
And this mixing angle alone could tell us what is the real, say, elementary particle physics.
Nature, well, I don’t know but anyway, well, to me honestly this has been the driving force for my study
because I was really excited about the large mixing angle.
Now, I am coming to the future, other observations to be made in neutrino physics.
I discussed this morning that we should experimentally observe
if the mass state, the third-generation mass state which is usually assumed to be heaviest but we do not know.
If we look back at the neutrino history we had a lot of surprises going on.
So maybe the third-generation neutrinos could be actually the lightest instead of heaviest. We have to measure.
In addition now people are thinking seriously that neutrino physics could be able to explain the matter in the universe.
Therefore experimentally would we would like to try to measure the CP violation effect as much as possible.
Also in addition a neutrinoless double-beta decay is, in my opinion, fundamentally important.
So there are lots of things to be measured in neutrino physics.
And they are really kind of beyond the standard model.
Thank you. And, last but not least, Professor Chu.
I said already you are not a particle physicist, however you are very well aware what this community is doing.
So what would you answer to the question about hints beyond the standard model?
Well, first let me say that there are at least half a dozen Nobel Laureates who are much more qualified than I to be sitting here.
And I think the only reason I am here is to encourage students to ask questions
because if they can have someone as ignorant as me here surely you can have interesting questions.
I would respectfully disagree with David a little bit on hints.
As an experimentalist we hope for hints but I would say so far there aren’t compelling hints
in the sense that in the neutrino sector anything that I know of still fits very well with the Kobayashi-Maskawa matrix.
But David can correct me, as I’m sure he will. (Laughter)
But let me tell you a little bit about, in my field, how we try to look at glimpses for breakdown of the standard model.
My thesis advisor spent many years of his life, this is Eugene Commins, trying to look for electric dipole moments of atoms
that could say that there would be an electric dipole moment of an electron.
Electron has a magnetic dipole moment but does it actually have a little bit of charge separation.
All the people have been looking for decades for a neutron having an electric dipole moment,
although the particle is neutral, can there be a slight difference in distance between a positive or negative component.
This is well beyond the standard model.
Indeed the symmetry, it violates both parody and time conservation.
We know CP is violated, there is a lot of attention being paid to the CP sector to what extent it’s violated
but no hint yet of parity in time reversal that will go beyond the standard model.
The most recent results out of a collaboration between Yale and Harvard on electron dipole moment
are beginning to close down the exclusion of what one calls naïve supersymmetry model,
the minimalist supersymmetry model phase base is running a little bit slim on that.
And so there’s a nervousness.
But of course there are many other variants on supersymmetry that allow you to go well beyond that.
And the standard model prediction, by the way, it does have a prediction for dipole moment
but it is well out of experimental reach.
So people look for precision measurements like EDM measurements.
The other thing I should say that touches on my field, or my former field, of atomic physics
is in quantum information and quantum fluctuations.
And in quantum information there are conundrums about actually
when you have coherent quantum pure states falling in and out, you know, partly in and out of a black hole.
And then the fact that you can have Hawking radiation.
There are dilemmas there where we know that our views of quantum mechanics, our views of what happens in a black hole, don’t match.
So there seems to be a contradiction.
And so that is a glimpse of something where, ok, there’s something.
Just like there was a contradiction of weak interactions and unitarity.
Excellent. David wants immediately to answer.
I just want to respond to, it’s nice that you think so much of theoretical experiments.
Neutrino masses as such are outside the standard model.
The standard model predicts a zero mass neutrino.
And it turns out that neutrinos have a finite mass.
And the question of, we have a nice speculation as to what the origin of that mass might be and why it’s so small.
It’s called the seesaw mechanism.
It requires that the neutrino be a Majorana particle.
That Majorana suggested and now condensed matter physicists claim to have observed in solid state. But we don’t know.
Neutrino’s beta decay would test that hypothesis which is extremely important, I agree with my colleague,
but that has not yet been determined.
It’s totally unknown and whatever their origin, the neutrino mass is certainly outside the standard model.
Dark Matter is a hint, it’s been experimentally observed and we don’t know what it is or what its properties are.
But I applaud your support of precision experiments.
And I think it’s somewhat unfortunate that the AMO community lost its interest in doing such high precision experiments.
They used to be the source of many high precision tests.
And now they’re sort of doing more many-body theory.
They can indeed shed light, but there are always long shots, stabs in the dark.
Thank you very much, David. We should now turn to CERN.
Again a very warm welcome to our friends in Geneva, some 400 kilometres south west from here, close to Geneva at CERN.
So first of all maybe not everyone knows but Fabiola Gianotti, our present General Director of CERN.
She has been very influential in the ATLAS experiment, a very key person,
and therefore also very important related to the discovery of the Higgs boson.
So Fabiola, we are very, very keen about hearing news from you.
You heard what I said at the beginning.
We have a very specific topic on this panel, so please tell us.
Good afternoon everybody, hello Felicitas. Can you hear me well?
Yes, we have a little bit of a delay but it’s ok, 400 kilometres one way, you know.
Ok, so good afternoon to everybody, to your very distinguished scientists
and all the people who are with you, in particular the young people.
The first thing that I would like to tell you is
that yesterday the LHC achieved for the first time the design luminosity, 10^34 cm-2 s-1. So it’s a great thing.
It’s the results of the effort for years, decades of work, hard work and it’s really a remarkable accomplishment.
Then the other thing that I would like to tell about the research for physics beyond the standard model,
I usually prefer to put the problem in the following way.
We are not running behind any theory, we are not running behind supersymmetry or dimension or other things.
We are addressing a direct fundamental question.
So the problem today is that the standard model works beautifully and we don’t understand why it works so beautifully
because there are so many open questions that the standard model is not able to address.
So we can think about the dark universe, 95% of the universe is made of matters and energy we don’t know.
We have the famous flavour problem. Why neutrinos have large mixing and quarks have a very small mixing.
Why neutrinos are so light and (inaudible) so heavy. So we don’t know.
And many of these questions have been mentioned before by more distinguished scientists that you have with you there.
So, of course, I am a strong supporter of high-energy colliders.
I’ve been working on high-energy colliders since I was a young student and they are very close to my heart.
And, of course, now as Director General of CERN, I am very proud to be in the laboratory
where we run the so-called Energy-frontier Machine.
However, let me be clear that the questions are so intriguing, so important and so intertwined that the only way to address them
with the hope of finding some answer, is to really deploy all approaches that this discipline has developed:
High-energy colliders, precision measurement, underground searches for dark matter, cosmic survey.
Professor Chu was mentioning precise EDM measurement.
Searches for rare decays, searches for weakly coupled, low mass particles.
So I think really we have to deploy all the approaches that we have developed,
thanks also to very strong advances of technology in terms of detector, in terms of accelerators, in terms of other instruments.
So it’s an exciting time with many important questions, with technological developments that enable us now to address them.
We should be as broad as possible.
Thank you very much, Fabiola.
I am turning now to, I stay with ATLAS and turning to the person on your left, namely Jamie Boyd from ATLAS.
So he sits 10 years in this experiment, now holding a staff position at CERN.
He has been very strongly involved in different aspects of running the experiment,
and, David will be happy, he loves to do searches for supersymmetry with the ATLAS experiment.
And actually since this year he does something more, he is the key link between all experiments at the LHC and the accelerator.
So Jamie, are you having exciting times now?
Hi, yes so as you say it’s really a lovely time at the moment because we raised the energy of the collisions in the LHC last year.
And last year was a bit of a testing year of these new energy collisions,
whereas this year we’ve really started running with very strong luminosity.
And in fact in something like 2 weeks, 2 good weeks now, we can take as much data as we took in all of last year.
So now we’re really in the position where we can start testing, searching in the data for heavy new particles
that were produced in these high-energy collisions that couldn’t be seen in one of the LHC, because of the lower energy.
So as you mentioned I am very much involved in searches for supersymmetry.
So here we are looking for heavy supersymmetric particles that are being produced in the collisions
and they decay into standard model particles.
And then in the most common theories of supersymmetry,
the lighter supersymmetric particle that’s produced in the decay chain doesn’t interact with the detector.
And what we look for is the so-called energy signature
where these particles pass through the detector and take energy away from the collision.
This has a nice link with dark matter because in many of these theories
this lighter supersymmetry particle is a candidate particle that could make up the dark matter in the universe.
So for me this is why supersymmetry is a nice theory,
why we can try and link together the measurements we made in astrophysics with what we can produce in the LHC.
Thank you very, Jamie. Turning now to the other person next to Fabiola, namely Daniele del Re from the CMS experiment.
He also is about 10 years now in this experiment,
holding now an associate professor position at the university “La Sapienza” in Rome.
He also has been involved in lots of activities within the collaboration.
He has been involved in the Higgs discovery, because he worked on the data analysis for the Higgs search,
and also is a fan of supersymmetry.
Daniele, how do you like now your work, what is the most exciting part of your analysis, now, this moment?
Thank you very much, Felicitas, for the introduction.
Yes, this is a very special moment for me.
Actually, I am coordinating the effort which is called "Exotic searches in CMS".
But exotic doesn’t mean you are in some exotic place or something,
it means that you want to go beyond the standard model and find new particles.
These events are happening now because we doubled the energy, as Jamie was saying before.
We doubled the energy with respect to previously and it is important to have more space to find new particles.
Various particles we have is under GeV 100 time the proton.
But now we can run a machinery which goes up to 13 TeV, which is 1,000 times the proton.
Now we have plenty of space to find these new particles.
It is exciting because the run started very recently and it is a lot easier to find these new heavy particles.
Thank you very much, Daniele. And, last but not least, on the very right side on the screen is Mika Vesterinen from LHCb.
He has been for 5 years in this experiment.
He is holding now a position as a Humboldt Fellow, hosted by Heidelberg University
but he is Finnish and British, both nationalities.
We lost you. You are back, I hope you are back? Do you hear us?
Yes.
Sorry, MIka, we lost you briefly. Besides all your responsibilities also you, of course, love labour physics.
You are in LHCb, you love beauty quarks
and you love to search for deviations from the standard model which might be a hint of supersymmetry.
So David, you see this young generation, they all love supersymmetry.
So just now, Mika, are you having fun with your data of 13 TeV?
Absolutely, so it was quite entertaining actually to listen to the discussion on precision studies of quantum effects
as somehow a portal to new physics because the LHC is actually a great opportunity for precision studies.
There’re so many particles at such a high rate.
For example, the LHC produces millions and billions of beauty particles every year
and that means that you can make very precise measurements of them.
So my experiment is LHCb stands for LHC beauty.
And the idea is that because we’ve produced so many of these beauty particles we can study very rare phenomena.
So you can look in particular at phenomena that don’t happen very easily in the standard model,
in particular because they involve force.
Now these types of phenomena can be easily helped by contributions from new particles.
And the hope is that by making very precise measurements and comparing with theory
then you can see some deviations that would be the indirect effects of new particles.
Now in our existing data set from Run 1 at half the energy we started to see a couple of hints of possible anomalies.
But what's exciting is that we now, we had this very long Run 2 of the LHC,
we actually produced beauty particles at twice the rate, we have a very long Run.
With improvements to our detectors. we’ll be able to make even more precise measurements.
So the dream is that we will already be able to see compelling evidence for physics in these precision studies of beauty.
Thank you very much, Mika.
So now the floor is open for discussion.
I have already some from the audience but Carlo is really burning.
I have a single question here since we have so many important people from CERN here, coming and telling us the latest news.
I would like to know what about that experiment of 750 GeV signal which is part of the unthinkable stories.
But still it's of great interest to all of us to know
whether the new statistics which you have collected now in the recent times have improved or eliminated such a question.
So can you get some latest news on this 750 GeV resonance?
So may I hand it over to Fabiola and her neighbours?
Since I am neutral, because I am not in ATLAS anymore and I have never been in CMS,
let me tell you, Carlo, it’s a very good question.
It's, of course, THE question that everybody is asking.
First of all I will not call it a signal, it was a hint, an inconclusive hint.
At the moment experiments are analysing the data that they have recorded.
Today the exhibit was delivered to each of us at CMS, as of today about 7, 7.5, last year it was 4 each.
So the statistics is almost doubled.
But experiment supplies only part of those data.
And they have not produced official results yet, so they are working and I hope we will know soon.
The time scale of a few weeks, I hope.
Are they smiling or are they crying? (Laughter)
I have tried in the corridor to detect any kind of emotion in one sense or the other.
But I can tell you they are extremely prudent and extremely cautious. So I can’t read from their faces.
So Jamie, why don’t you show your face? Are you smiling, Jamie from ATLAS? (Laughter)
I am trying my best to do a poker face. (Laughter)
What about Daniele, CMS?
I am smiling, actually looking for it, it’s a pleasure. So I am happy.
And Mika is the observer.
As another unbiased person it’s funny for me to look at this from the outside as well.
I mean fingers crossed for ATLAS and CMS friends.
Maybe just to add to what Fabiola said.
So I think at least the results for the ICHEP Conference which will be at the beginning of August.
So by this time we hope that we will have enough data to be able to really say something conclusive.
And fingers crossed it’s something exciting.
Excellent. I'm at the same time trying to find out which type of questions you from the audience have been sending.
So therefore just that I have time to look at this and I give now the floor first to the panel to ask questions to CERN.
We again have lost you. Do you hear us?
Yes.
We hear you also but we don’t see you, which is a pity. But nevertheless we can ask you questions.
So someone from the audience. Carlo has already asked. You're back. Someone else from the audience direct questions?
No questions to CERN?
Well, Carlo’s question.
The key question.
But we’re not going to get an answer.
Looks like it. So now the audience question I have now.
The first question which I received was from India, someone with I think family name Mondal.
So you ask, we might have already hints for beyond the standard model because of this 750 GeV bump into photons.
But your question is if we do not see any conclusive evidence of beyond the standard model at the LHC at 13, 14 TeV
in the years to come, should we go to higher energies or do we need more precision, that means more luminosity?
Fabiola, maybe a question for you.
Both, we need higher energy and we need higher precision. (Laughter)
And again not only through colliders, we need, of course, higher energy, higher luminosity colliders
but also as I said before also through other approaches because we don’t know where this new physics is. We know it’s there.
We don’t know whether this new particles, new phenomena, new forces, are hiding themselves.
So we will have to find them and we will have to know for sure.
CERN clearly is a laboratory that has an historical and tradition and history
and the capabilities of building high-energy accelerators and high-energy colliders.
So I think we will continue in these directions.
But we will also continue to promote a scientific diversity programme, studying for instance matter-antimatter differences,
contributing also facilities elsewhere in the world etc. But we need everything.
Ok, as expected.
So now I have a question from UK, from the University of Cambridge.
So this is a very general question:
"Large projects like CERN, LHC or the Hubble telescope –
data obtained from this project has to be subjected to reproducibility tests.
And these tests have to be done by independent people in independent set up.
Isn’t this part of a scientific enquiry?"
So how would you answer this question at CERN and then my experimental colleagues here on the stage?
Did you hear, that you need in order to have a reproducibility test,
you need independent people to repeat this thing, experimental results?
So what would you answer to this young person's question from the audience?
(Laughter)
According to the text book – yes, the answer is “yes”.
Definitely we need the result to be produced by someone independent.
But now the question is each experiment is getting more and more expensive.
And sometimes it’s getting more and more difficult to have the 2 independent experiments.
So this is I think going to be a very important issue that we as a community have to discuss.
So I don’t have any answer.
David, maybe you have, as a theorist, an answer to this.
Theories also need to be confirmed by other theorists.
You know the discovery of gravitational waves is perhaps the best recent example of a discovery
which was so conclusive, so expected and so in agreement with precise theoretical calculation
that it seems that everyone accepted it without any independent confirmation.
Although the experiment itself, LIGO, has now come up with continuing observations.
That helps to make the case even stronger.
But it does prove that it is possible to convince the world of the reality of a discovery.
The same is true, by the way, of the first indirect observation of gravitational radiation by Hulse and Taylor.
There was no other confirmation of that and they received a Nobel Prize without an independent confirmation.
So if the theory is really good and predicts something then it’s conceivable that we accept it without checking.
But in a facility like CERN where they’re exploring unexplored territory
and theorist tell them all sorts of speculations like supersymmetry, they shouldn’t take theory too seriously.
And they should go ahead and explore and then independent confirmation is really very important, I think.
And we can take an example from again atomic physics and precision measurements.
In the early days after QED there was great activity to try to see
if there’s a breakdown in QED by testing higher order corrections.
I think the precision measurements and the B-physics are going to go after looking,
you know, higher order rate of corrections to various diagrams and whether there’s going to be a breakdown.
If there is that’s going to be great but there may not be. There is all sorts of things.
But going to the fundamental question, as you go to more and more expensive - at least they have 2 different detectors.
But if you go to more and more, looking into the future it’s getting harder, it’s even getting harder in quantum electrodynamics.
There’s one person who does the QED calculations now.
And there’s maybe another person.
The precision measurements and EDM thankfully they are inexpensive enough that if there is a hint
there will be a half dozen that will quickly emerge with slightly different technologies.
If there’s any hint of what dark matter is about there will be enough low-budget experiments to actually descend on it.
But the highest energy ones, you know, what comes after LHC, what other collider,
IF there will be one, it will be, you know, ONE collider.
But hopefully more than one experiment.
Hopefully more than one experiment, at least having fundamentally different detectors.
Yes, this is what I mean.
That’s very important.
Thank you. I should also now tell you a secret that we have, if you have an urgent question and you want to interrupt,
to make a lively discussion, we have some microphones.
And so you wave your hand, you make yourself visible and then we can hand over the microphone to you.
So I have now another question from Boris Bolliet from University of Grenoble.
He asked the following: "Today what is regarded as the most relevant explanation to the non-zero mass of neutrinos?"
That is the question for the theorist.
Lucky we have a theorist in charge today.
In the standard model the neutrino is described as a left-handed particle with no right-handed partner.
Now, if you’re massless that’s ok, but if you have a mass you can be brought to rest
and then rotated and become a right-handed particle.
So you can’t have a particle with mass that has a definite chirality.
For many years neutrinos had such a small mass that it was undetectable, and, in fact, originally
when parity was discovered to be violated, people thought, ah, now they understood why neutrinos don’t have a mass.
Mass was then discovered.
The neutrinos oscillate, one neutrino turns into another and therefore they actually must have a mass.
We don’t know the absolute value of their mass, that’s one of the great unanswered questions experimentally or theoretically.
But they have a mass for sure.
The origin of that mass requires that there be a right-handed neutrino.
You can easily add on to the standard model a right-handed neutrino.
And in fact in some simple unifications they naturally occur.
Then there’s the question of why the neutrinos are so light.
Both issues were addressed in a lovely theoretical suggestion by Gell-Man and Ramond and Slansky way back,
the so-called seesaw mechanism, which says that if the neutrino is a Majorana particle
and there’s a right-handed partner which is very heavy then the neutrino we observe will be very light.
That requires a new scale of high-energy physics, around 10^10 GeV,
slightly higher than the LHC but not as bad as the Planck mass.
But that’s an open possibility.
There is a direct test as to whether neutrinos are Majorana particles or not: Majorana particles are their own antiparticles.
Therefore in nuclear decays where a neutrino, 2 neutrinos are admitted
they could annihilate and you’d have neutrinoless beta decay.
That’s been searched for experimentally for years and years.
Now we’re at the stage where conceivably within the next 10 years we’ll settle the issue.
Anyway, that’s the idea, the theory, the speculation as to where the neutrinos might acquire their mass
but it is not settled yet experimentally.
Are you happy with the answer?
Could I make a small comment on that?
Yes, of course.
Now I want to say one simple remark that neutrino mass differences are known.
Neutrino masses per se are totally unknown, and there are some experiments going on at the 1-electron-volt level.
But this is probably too far in respect of what nature is.
So there is tremendous gap, lack of knowledge about neutrino masses.
We still have to have renewable experiments to get the result there.
Yeah, there are eV scale end-point measurements, there are astrophysical limits that say it’s, as you say, below 1 eV
but where below that we don’t know.
And then the double-beta decay, actually, has been seen but not the one you want yet, neutrinoless double-beta decay.
So it’s a fixed end-point energy.
But there, again, 20 years ago we didn’t even know whether we had the sensitivity to see a second-order beta decay.
And we see that.
Thank you. I should say that Fabiola will have to leave us at 4 o’clock, so in about 10 minutes from now.
If you have here some questions still to Fabiola, this is your chance.
The other three are staying till the end of our session.
And maybe it is also now the moment where we can ask you, all four of you, if you have questions to the panel members from CERN.
No?
I would be happy to ask a question related to their opinion of the next future facility for high-energy physics,
so the same questions that were asked of Fabiola.
What’s the next step in their opinion to try and understand going beyond the standard model?
So who wants to answer? David? Carlo? You? You? David.
I am, like Fabiola, a great fan of colliders.
It’s true that everything would be good and everything is necessary.
But we’ve seen with the LHC, the range of new phenomena that just higher energy buys you.
So I believe strongly that no matter what happens in the next few years with Run 2 and the future years
that it is incumbent upon the human race to build a further next-generation 100 TeV-ish particle collider.
Because with energy, with high precision, you can test our basic principles and perhaps get signals of new physics.
They are difficult to interpret and they don’t necessarily tell you where to look next.
Whereas with high-energy colliders history has shown that when you get beyond the threshold for new physics,
totally new worlds open and new phenomena that you didn’t dream of appear.
That’s how we’ve made progress in the past.
And 10 TeV, 13 TeV, is really just the beginning of the right scale to probe the electro-weak regime of physics.
The field in which I worked initially, the strong nuclear force, the relevant energy scale is about a few hundred MeV.
And to really understand the strong force and to test our QCD, and we still have a lot to learn about the strong interactions,
we needed machines that ran with 1000 times more energy.
The scale of the electro-weak sector is more like 100 GeV,
we need to go to 100 TeV to truly understand, I think, physics at what we now call the low-energy scale.
So I’m a strong advocate of higher-energy machines at CERN or elsewhere.
When I was US Secretary of Energy for 4 1/3 years, the debate, the feeling was that muon colliders, the issue is luminosity.
And so at least at that time it didn’t look like it was imminent.
And then the question is an electron collider or a proton, anti-proton collider.
And I think whether it gets built or not with a world collaboration, we don’t know.
But the feeling was that for a discovery machine, exactly what David was talking about,
just go to raw high power rather than put it into an electron collider.
Let me also add a little bit.
This is the first time I think in history of human civilisation, in the last 500 years certainly,
where one is faced with very open scientific, clear scientific questions, deep scientific questions – dark matter, dark energy,
all sorts of things where the world might collectively say, we’re not going to go there, we can’t afford it.
And this never happened really before.
You know you could, you know Columbus can appeal to the Queen of England and say
hey, you know, where he wasn’t getting this - sorry Queen of Spain, I am sorry.
I had England on my mind, very different from - separated now, but never mind.
And it would be tragic if we could not be able to build 100 TeV accelerator or whatever scale would be appropriate.
Society can afford it, it’s just whether they choose to build it is the real question.
Thank you, any other comment from the panel to this question from CERN?
Certainly I agree that it is important to have the higher-energy colliders
but please do not forget about the underground experiments. (Laughter)
So perfect transition to the next question which I have here from Eduardo Olivia from Spain, from Madrid.
He asks, "If you had to bet on neutrinos being Dirac or Majorana particles which one would you choose
and what would be then the consequence of your choice?"
I certainly choose Majorana.
Otherwise, well, according to theorist, we have no way to understand the smallness of the neutrino masses.
Anyone has a different opinion?
It’s also Majorana particles are really cool! (Laughter)
I have to say that with the Majorana I just saw three days ago in a quantum computer
that they’re having Majorana quasiparticles being used now to do quantum calculations.
They're beginning to go and search. So it’s a really crazy mixture of fields.
On the surface of various materials, Majoranas are actually anions.
They have strange statistics when you move them around and they can be used to store protected quantum information.
In three dimensions, however, in the world we live in, Majorana particles are ordinary fermions.
I have the next question from the audience, from India.
Your question was, the direct detection dark matter nucleus cross section is very small
and eventually will hit coherent neutrino background.
Now, you pose the question how can we design experiment where this neutrino background is irreducible?
But I think you want to say “reducible”, that you get rid of it?
You want to have an experiment where you have no neutrino background anymore, is this your question?
I understand the question.
And do you know the answer?
No, I am not an experimentalist.
But you know, the question is in dark-matter detectors underground, there is, you can shield against neutrons
and radioactive emissions that give you a background to what you’re looking for, the dark matter particles.
But neutrinos can’t be shielded against them.
They will give, at a certain level of detection, a background that is unshieldable.
But my answer to that would be, experimentalists are extremely clever, number one.
Number two, backgrounds are backgrounds.
And if theorists work very hard and experimentalists measure a lot, you can calculate the backgrounds.
After all at CERN they try to pick out one event of a billion background events and they use theory and measurement.
So I am not that worried, besides which I expect that dark matter will be seen before they get to that level.
Yes thank you, we all hope that this is true.
So since we are approaching 4 o’clock, Fabiola, you want to say something, contribute to the discussion?
Well, thank you, at least concerning the last question actually, I am not an expert of underground detection.
But as far as I know to defeat, you know reducible background the way would be to measure the direction,
the rationality of the signal because of course this could point toward dark matter clusters.
And clear localisation in the galaxies would have neutrino backgrounds more diffuse.
So as David was saying experimentalists have quite, you know, a lot of fantasy
and so people are already thinking about the so-called reducible neutrino background.
And now coming to your question, Felicitas, to repeat what I said before.
I think for the young people there, you know it’s a fantastic moment.
It’s a fantastic moment because we have this beautiful thing that is too successful
because it works so well but we don’t understand why.
And there are so many exciting questions out there.
And at the moment we human beings have to develop our ideas and our ingenuity to find the best way to address them.
Thank you very much. Also thank you very much, Fabiola, that you took the time in you’re very, very busy schedule
to talk to us here all for one hour. And all the best wishes.
And everyone is now tuned to listen to whatever news when we start the ICHEP conference beginning of August in Chicago.
So there we will get the news about the questions Carlo was posing.
So thank you very much and the other three please stay on.
Thank you, bye-bye.
There is a question from Logan Clarke from Chicago University. - Okay, so I don't have to repeat.
There is a question which is really not quite the theme of "Beyond the standard model" but it’s a question to Professor Carlo Rubbia:
"While clathrates may provide enormous energy potential, threats to ecosystems do exist in its mining.
So shouldn’t we try to look towards fusion reactors instead?"
I think fusion is a number of – if you want me to answer.
Fusion as is intended on the Sun is a non-aneutronic weak interaction process
which emits no neutrons and runs for billions of years, 8 billion years more or less before being distinguished.
The fusion reactor then on earth is based on combining deuterium and tritium together into a strong interaction process.
So there is a fundamental difference between what happens today with ether
and whatever is possible worldwide, you know, cosmoswise from the point of view of productions of fusion.
In fact there are many, many fusion reactions which are now around, every reaction like nuclear is a fusion reaction.
I am a strong believer of aneutronic fusion reaction, fusion reaction which emits no neutron.
For instance there is one process in which you take boron 11 plus a proton and that gives you 3 alpha particles with it.
This is a process which is not much more complicated to the one which is done by ether
but it has a tremendous advantage of producing zero gammas, zero betas and 3 alphas,
which are of energy of a few MeV, which can be slowed down to create electricity.
Such a system has absolutely no risk for producing background emissions and is in my view the right place.
So I would use less effort and less money and less difficulty in going to ether
and put more money in looking at unthinkable ideas like aneutronic process as one example I gave you.
Could I just add a little to that?
So there is a start-up company in Southern California called Tri Alpha that is actually trying to develop it.
And its order of magnitude harder, if you kind of the loss in criteria scale.
They have decided in the next embodiment of what they’re going to do, actually going to try tritium deuterium
just to see if they can get a high enough, you know, time energy density temperature to see if it will work.
But, yes, because the standard fusion that is being explored at ether or inertial fusion
creates high-energy neutrons that have huge material damage that is an unsolved problem.
So the neutrons will essentially create engineering problems that we do not know how to solve yet.
Correct, there are 5 times more neutrons coming from fusion than there are coming from fission.
And the fusion neutrons are high energy. Is that not the right direction to go?
Thank you. So turning back to particle physics, Andreas Mayer from CERN, where are you?
Unfortunately your question arrived a bit too late for me because it would have been interesting for Fabiola.
So the question is, "Is there already a compelling reason why we have not seen the 750 GeV hint in 2012?
And secondly, have we seen the Higgs boson at 13 TeV already?"
So we have still two experimenters there, represented by our two young colleagues, can you answer the question first?
Can you repeat the first part, we had lost the connection.
The first question was, is there already a compelling reason
why we should not have seen the 750 GeV hint in 2012 at 8 TeV centre-of-mass?
I think the question is, why we didn’t see the 750 GeV excess before in the previous run, right?
In 2012, yes.
Actually, we analysed both data sets and what we have seen so far is quite consistent between the two data sets.
So there are no inconsistencies.
Things can fluctuate at the end, everything is driven by statistics.
I mean, you see a smaller hint at 8 TeV in 2012, and you can see larger hint of Sigma
and then you can see lower hint in the future.
Everything is governed by statistics.
And it’s very consistent at the moment.
Jamie, you would agree with that?
Maybe just to add. True. The ratio of what you had in the 2012 data, 8 TeV, depends also on the production mechanism.
So if you expect this new particle was made by a gluon fusion
the data sets are more compatible than if you expect it to be made by a quark fusion.
And this is, of course, something we don’t know.
So in the long term this could give us a hint, if we see more evidence for this particle,
we could learn something about this from the ratio of the production cross section in these two data sets.
Thank you. And what about the Higgs confirmation at 13 TeV centre of mass? This was the second part of the question.
Do you see the Higgs now?
The point is that it is not yet given the statistics smaller.
So despite what has been said before, at the energies of the 8 TeV data set is much larger than the 13 TeV data set,
the way the Higgs is produced.
And for this reason I mean we have clearly evidence that data is there but we cannot say it is more than 5 Sigma.
I don’t know if this question has been solved because we know very well the Higgs is there.
So I am quite sure, very confident that we are going to see it.
From an ATLAS perspective, actually, if you look at the results that were released at the end of 2015 with the Run 2 data,
in fact, ATLAS saw what I will say is an under-fluctuation in the number of Higgs bosons.
So what we saw was consistent with the Higgs, with what we expect, just due to the size of the data set.
Whereas if I look at the CMS data I think they see exactly the number of Higgs bosons that they would expect,
the plots look nicer and it looks more convincing,
but in fact both experiments are consistent with the hypothesis that is there with the expected rate.
Thank you very much. It’s very interesting for the young students amongst you,
how one talks about the results of the other's experiment without really wanting to tell too much in detail
because everything is rumours for the time being. Isn’t it so?
But, again, in the beginning of August we are going to have very likely new results,
also on the Higgs sector at the conference in Chicago.
Now another question from Arizona State, Steven Sailor.
The question is, "What do you think about the potential of plasma accelerators as a promising alternative,
particularly in terms of cost efficiency as a means for reaching higher-energy scales than the LHC in the near future?"
Carlo, perfect question for you.
Well, first of all let me say plasma accelerator is a very interesting question which has been going for very many years.
And a lot of people have developed very interesting ideas on this subject but still it is a very small scale situation
and we would like to see the plasma physics to operate with much higher energy.
We are talking about GeV per metre but on a small scale within a realistic experiment before going to a much bigger one.
The second problem associated with plasma is the beams are very small and very tiny.
And to create the necessary luminosity requires a certain substantial amount of evidence.
And therefore the plasma business not only has to solve the question of making a bigger machine, a more expensive machine,
a more practical machine but also solve the question of luminosity, because luminosity now is going to be the real limit.
Today every time we go up a factor of 10 in energy, we are going to go down a factor 100 in luminosity
because the luminosity is like a square of the energy.
And therefore there will be a fundamental luminosity limit which will come along,
which will be as serious to fight as many other limits.
The energy per se is possible but the luminosity is really the question which makes you see the real physics
which will occur only a very tiny little property
because the cross section of colliding in two particles depends on the cross section of the particles themselves.
The higher in energy, the smaller the particles are, the smaller is the cross section.
And this is a big problem which the plasma physics will have to solve in order to become competitive.
At least not in the near future. Let’s be optimistic. Thank you, Carlo, for the answer.
Next question comes from a participant from Australia, Jackson Clark.
So your question is, "In your opinion, are rumours of tentative or new physics’ signals dangerous
for the application of the scientific method or damaging to the credibility of the experiment?"
So what would you say? Who wants to answer to that?
You can’t stop rumours. Physics is a human activity and big science is a big human activity with many humans and they talk.
But what you can do is behave correctly.
And we have seen different examples in the last few years of both good examples -
I think the Higgs discovery and the way it was done by CERN is a great example, LIGO is a magnificent example -
and we’ve seen bad examples, BICEP is perhaps the most notable.
And there is much to be learned by the scientific community from the good examples and from the bad examples
but it is impossible to suppress rumours and one shouldn’t try.
But the scientific groups should behave themselves.
And, for example, not release by press conference new discoveries before they have a peer-reviewed paper.
Let me add a little bit to that.
And that is there is more of what we call blind methods of analysing the data.
It’s especially true in precision experiments, but you can go in there and scramble something
and you analyse the data and you don’t know what’s going to, and then it comes together at the end,
so that you prevent people from emotionally chasing after little bumps and things of that nature.
Those methods of blind analysis are improving and getting better,
deliberately, to try to take out the hope that there might be something here or might be something there.
And they’re getting more sophisticated as well.
Thank you. Do you want to add something to this? It’s an important question of contact in science, of scientists.
Next one, again from Australia, Joe Cullingham. He asks - maybe a question to David -
"If supersymmetry is ruled out by the LHC,what are the options that remain to explain the efficiencies in the standard model?"
You don’t want to have ruled out the supersymmetry, I suppose, but nevertheless what would you say?
There are many ideas that people put forward,
not as compelling as supersymmetry which, being a symmetry, is incredibly predictive.
One of the reasons these people at CERN like supersymmetry is even though there are enormous range of allowable parameters
but it’s quite predictive, it tells you what kinds of events to look like but not necessarily at what rate they will occur.
There are many, many other possibilities and it’s interesting, the 750 bump shows very little signs of being something specific.
Very little information about these excess of events
but it did generate 200 or more, 280, 300 I don’t know, many, many theoretical papers.
And some of them, actually, had some interesting new ideas.
So theorists are, you know, clever and can respond to observation, to nature.
And if supersymmetry is bounded, ruled out in the current range of parameters explored at the LHC,
that will be a very important discovery, the discovery of how nature works.
And we’ll learn actually how nature works.
And I’m sure some young people sitting in the audience perhaps will, with that added knowledge,
come up with some new ideas, better than anything I can come up with at the moment.
Thank you. Another question from the audience, namely from Katrin Kröger, ETH Zürich:
"The idea of a physical theory explaining everything, from the quantum world to the universe and beyond,
is a very fascinating and beautiful goal.
But do you think that mankind will at some point actually arrive at the complete theory
or that it will be a never-ending quest, always leading to new questions?"
I think you are the best candidate.
I'd give an hour-long lecture on this topic which I’ll spare you.
And I’m totally agnostic. I often compare it to exploring the Earth.
If the Earth had been flat you would explore it forever which is good, actually,
it means you always have new lands to explore and new things to discover.
It turned out to be round and we have a final map of the world, at least at some scale.
And that’s very satisfying but it actually had meant the end of explorer societies.
I don’t know about knowledge and the structure of physical reality.
It might go on forever, it might stop - who knows?
All I can say is there’s absolutely no sign for curvature.
It looks pretty flat as far as we can tell.
There are always new questions and they’re wonderful.
So if you confine it to what we call high-energy or fundamental physics that’s one thing but there are other things.
You know, David talked about, is space and time an emergent phenomena that comes out of fluctuations of the vacuum?
Well, there are many other forms of emergent phenomena like life.
You know, how do you go from molecules to something that self-organises in a way that is life how you define it?
So what we are going to be learning about dark energy and dark matter,
what we know about quantum mechanics and beyond and the higher complexity
will tell us more about what’s going to happen with life and what we need to know in chemistry and biology.
So there are many, many stages of things to explore.
Yes, there are cartographers, we now have Google maps and so we don’t need explorers of that sense.
But then if you dip a spoon into the ocean, if you dip a spoon into the soil you find microbes
that you can’t culture in the laboratory, that you don’t know what they’re doing,
you don't know how they’re working with each other to help in the feeding of a plant.
Just as we are only getting a glimpse of the microbes in our gut
and how that is intimately intertwined with the immune system and, we now think, mental processes.
So there are emergent phenomena that aren’t at the most fundamental physics level, that are also very exciting.
If I could add to that, not only in biology but even in, more old-fashioned, non-living matter, solid state matter.
I’m not sure that we have, you know, begun to understand the possible forms of matter.
Now that we can manipulate individual atoms and put them in different positions,
we’re no longer restricted to the type of matter we found stable on earth.
And the vistas there are quite possibly enormous.
So even in physics - we don’t necessarily have to go to living matter.
We still don’t understand that there’s several newer classes of superconnectivity, as an example.
So I turn to the last question from the audience, from Nicholas Iris from the University of Sussex:
"Panel members, if you had to bet on one beyond-the-standard-model extension, which would be your favourite?" Carlo.
Well, perhaps my answer is, yes, but not within my lifetime.
I am afraid that the situation of the expectation to get a real new standard model is so good, that things are so nice
that the chances that we have to divert those things in a revolutionary way, it’s something which will take a very long time.
Look at the situation we just heard at the beginning.
We said until 2035 we are going to have a high-luminosity LHC.
Then after that I suppose we’re going to have high-energy LHC and then maybe that will give you 50 TeV
and then the question is we want to make 100 TeV machine, is 100 enough, do you need 200 - I don’t know.
It seems to me that we should be very proud of the fact that the standard model works so well.
In a certain sense be content with it and say that, in fact, although we can always expect nature to be different
with the probability that such happens within a reasonable lifetime, is extremely small as far as I am concerned.
Since we do not know what to be beyond the standard model, so I think it’s important to have various directions we go.
And I realise that I have one thing to mention.
That is the search for proton decays, that is obviously evidence for the unification of the forces.
Therefore this is one of the things that we should not forget about.
Very important question, I still remember when these gentlemen theoreticians were telling us guaranteed within 10^30 years.
And now we are about 10^34 years and still we have a problem to go higher with that and so forth and so on.
So it seems to me that nature is much tougher than we expect when it comes to it.
And I agree proton decay is an important question but you know a factor 10 is a big factor
because we are not working in logarithmic paper, ok, linear paper.
So I assume that your neutrino physics will give us a good story about proton decay,
certainly one of the most important ones.
But the question is whether, as was said, diamonds are forever, as Shelly Glashow was saying,
that is still an open question and will remain so for a long time as far as I am concerned.
Thank you.
Don’t confuse me with Shelly Glashow.
Proton decay would be fantastic because it’s a direct window to the unification scale.
Unfortunately, the rate appears to vary quadratically with the energy scale.
So it’s really difficult but it would be wonderful.
So I’m not sure what 'favourite' means.
I think the most likely is to understand the nature of dark matter since we know that dark matter exists.
And the second most likely is to understand the origin of the mass of neutrinos which we know exists.
My favourite, I must say, continues to be supersymmetry because it’s the most – it’s a new symmetry and it’s beautiful
and it explains many things and fits nicely into our far-out speculations about unification.
Well, these are speculative wish lists but I would somewhat agree with David in the sense that dark matter -
there are fishing expeditions but they are important fishing expeditions.
There are many ingenious ways one can look for these things but who knows what nature is really going to be like.
But we’ll see in the next 5, 10, 20 years.
Hopefully one of these fishing expeditions finds something.
And it is unequivocal, we know there is stuff there.
So before we close this session I would like to invite the panel members to just, in a few words, a few sentences,
say what you take home from this session, what you like, what you think this is a new thing, what you learned.
But I don’t only want that the panel members say this, I would like to have also a few of you young participants of the audience.
Think about that and if there are not some who say, yeah, I’ll just take someone of you and then you come here on stage.
We'll do it the old fashioned way, you get the microphone and you can give your personal conclusion of this panel discussion.
So first panel members. Carlo, so what would you say?
I stay last this time.
So then we start here.
So what are we supposed to talk about now? (Laughter)
What do you think is the message you take home from this discussion, this panel discussion.
How would you summarise this?
Maybe you say, ah, it was just a waste of time (laughter) or you found it interesting.
I always find these interesting.
I think we’re always physicists – I think, to the students, that scientists, not just physicists but scientists in general,
are always very excited, very hopeful that they will have a new surprise.
Something not predicted, something totally new, because that’s the thing which we really live for.
If you are just verifying something else and it gets better and better that’s important. That is how science progresses.
But what we were really talking about today, beyond the standard model in all its various forms,
is we want a surprise and we’re desperate for a surprise because that’s what really gets us excited.
Yeah, you know, so the people who are sitting up here are old. I mean we’ve had –
Speak for yourself. (Laughter)
But the particle physicists up here have lived through -
we are old enough to have been in a period before the standard model was confirmed.
And that was exciting as well.
There were discoveries all the time and we had no really good theory at all.
And that was a lot of fun.
So everyone is looking beyond the standard model for something new.
But I want to say a word about the standard model.
And you know after that period we’ve ended up with a pretty good theory.
With a few parameters that explains in the reductionist sense just about everything we’ve observed with incredible precision.
That’s also very satisfying.
So physics, you know, goes from not understanding anything, discovering new things, being totally confused,
understanding and completing this incredible theory and then being frustrated because we haven’t explained everything.
And there are a few new phenomena and now we’re ignorant again.
That’s how physics progresses.
And if you’re lucky enough like I was, you can live through all of those stages of confusion, ignorance, glimpses of understanding,
confirmation of understanding, standard model and now, once again, perhaps we will be lucky enough,
or you will all be lucky enough, to go through a similar cycle.
I think basically I am going to repeat, yes, standard model is so great.
But we have already some kind of hints beyond the standard model.
And therefore I think it’s important to look at various ways to go beyond the standard model.
So I think we have a lot of things to do.
If I may add quickly the answer.
It seems to me that first of all as an area for great unexpected discoveries, I will certainly prime neutrinos.
The neutrino seems to be the right horse to go and figure out things.
And it seems to me that one thing we haven’t discussed, which I think we should have discussed a little more,
was the connection with dark matter.
We know that dark matter is an existing phenomenon which has had revolutionary results over the last several years,
beautiful results have shown that the dark matter is a reality.
Now, it seems to me in a certain sense that the question of standard model
should also have some function to do with the question of dark matter.
For instance, are neutrinos part of dark matter?
If so what kind of role do they have in dark matter or is neutrino one thing and dark matter something else?
And if it is something else what is it?
I mean we sooner or later will have to know that.
So that seems to me is the kind of problem which I personally find most exciting:
the possible relationship between neutrinos and neutrino oscillations,and dark matter.
Thank you. Now I am going to look into the audience.
Can you come up to the stage, please?
Say your name, where you come from and then...
Julieta Gruszko from University of Washington in USA.
Something that struck me listening to all of your discussions is
how pervasive the nation of elegance is in what theories we prefer.
And I think this is something that’s really special about physics.
Other sciences don’t seem to expect that the universe will hang together in this kind of beautiful way.
And I find myself wondering whether the experience of going from all these new particle discoveries,
without a unifying theory behind them, to the standard model has trained us to expect an elegance that we shouldn’t always expect.
That whether this particular experience of the last century has created a false promise of elegance.
Just as something to think about.
Thank you very much. Excellent. Second one.
My name is Patrick Bracy, I’m a graduate student at Johns Hopkins in the USA.
What I have kept thinking about during this session is the quote that David shared with us this morning
about Einstein saying, "Nature is subtle but not malicious."
And it kind of feels like we’re living in this exciting but also slightly frustrating time
where we have all these really tantalising hints of new stuff.
And some of them are going to turn out to be interesting.
Some of them are going to turn out to be statistics.
And if nature isn’t malicious some of them will turn out to be worldchanging.
So it was a really interesting session, thanks a lot.
Thank you very much. Next one, here.
My name is Guy Marcus, I’m also a graduate student at Johns Hopkins.
But I’m in kinetics matter, solid state specifically.
So just to let that shade how you hear my comments.
So I am also someone who has, not struggled, but had had the problem of liking lots of things and being very interested.
I was actually first inspired by Bera and Genesis.
So I’ve sort of gone through that process of thinking about particles and such.
But it’s for me, now having settled on where I am, an exciting time for a solid state physicist
to see particle physicists sort of struggle around a little bit because that’s all we ever do.
And we’re still making progress.
So I was very glad to hear, I mean, just seeing this kind of conversation at this kind of stage is very, very fun.
And also very informative to sort of see how you guys talk amongst yourselves.
And also women, for that matter.
Now, I appreciated the fact that particle physics stars as well as condensed matters
bringing back in the fact that, hey, we’ve talked about Majoranas already,
we sort of see these sort of particle physics claimed ideas in something we can touch.
So this is sort of hard to bring to the public, but I’m glad to see that we could at least talk about it amongst ourselves.
Thank you very much. One more?
We had three. Excellent. Thank you very much.
I am going to close in a couple of seconds this afternoon session,
but first, of course, I would like to thank everyone who has been involved in this –
our fantastic panel members, all three of you thank you very much for being so lively in the discussion.
Also a great thanks to you in the audience.
You have had also more questions to pose but unfortunately for time reason I couldn’t -
at the end there were many more coming in and I couldn’t really say all of them, read all of them.
Thank you for your participation.
Thank you very much and still enjoy this week.
Have great fun with physics.
(Applause)