Archive for CERN

The Case for Irish Membership of CERN

Posted in Politics, The Universe and Stuff with tags , , , , on November 16, 2019 by telescoper

In the news here in Ireland this week is a new report from a Committee of the Houses of the Oireachtas making the case for Ireland to join CERN. You can download the report here (PDF) and you’ll find this rather striking graphic therein:

You will see that there are only three European countries that don’t have any form of membership or other agreement with CERN: Latvia, Bosnia-Herzegovina and Ireland. The fact that almost everyone else is in is not in itself necessarily a good argument for Ireland to join, but it does make one wonder why so many other countries have found it to join or have an agreement with CERN while Ireland has not.

As the document explains, if the Irish government  were to decide to take Ireland into CERN then  it would first have to become an Associate Member, which would cost around €1.2 million per year. That’s small potatoes really, and  the financial returns to Irish industry and universities are likely to far exceed that, so the report strongly recommends this step be taken. This Associate member stage would last up to 5 years, and then to acquire full membership a joining fee of around €15.6 million would have to be paid, which is obviously a much greater commitment but in my view still worthwhile.

While I strongly support the idea of Ireland joining CERN I do have a couple of concerns.

One is that I’m very sad that the actual science done at CERN is downplayed in the Oireachtas report. Most of it is about return to industry, training opportunities, etc. These are important, of course, but it must not be forgotten that big science projects like those carried out at CERN are above all else science projects. The quest for knowledge does have collateral benefits, but it a worthy activity in its own right and we shouldn’t lose sight of that.

My other (related) concern is that joining CERN is one thing, but in order to reap the scientific reward the government has to invest in the resources needed to exploit the access to facilities membership would provide. Without a related increase in research grant funding for basic science the opportunity to raise the level of scientific activity in Ireland would be lost.

Ireland recently joined the European Southern Observatory (ESO), a decision which gave Irish astronomers access to some amazing telescopes. However, there is no sign at all of Irish funding agencies responding to this opportunity by increasing funding for academic time, postdocs and graduate students needed to do the actual science.

Although astronomy is clearly much more interesting than particle physics (😉) in one respect the case of ESO is very like the case of CERN – the facilities do not themselves do the science. We need people to do that.

The Strumia Affair

Posted in Politics, The Universe and Stuff with tags , , , , on October 3, 2018 by telescoper

I’m very late to this story as it broke over the weekend when I was preoccupied with many things, but it has triggered quite a reaction in the media (including here in Ireland). The story involves a physicist by the name of Alessandro Strumia who works at the University of Pisa in Italy. This person used the opportunity provided by a Conference on Theory and Gender to deliver a talk that contained highly inflammatory comments about gender and physics ability.

As a service to the community I’ve uploaded the slides for Strumia’s talk to Slideshare so you can read them here if you’re interested in his argument:

There are detailed discussions of Strumia’s talk by fellow bloggers Philip Moriarty here and Jon Butterworth here. Between them they cover most of what I’d say on the topic if I had time so I’ll direct you to them rather than repeat the arguments here. There are a host of other reaction pieces elsewhere, and I won’t attempt to summarize them either. Suffice to say that the old argument that `women are intrinsically not as good at physics as men’ has been refuted many times using solid empirical evidence; see the above post by Philip. It’s no wonder, though, that women get put off doing physics, when there are people like Alessandro Strumia in the field and potentially responsible for evaluating the performance of female staff.

What I will do add is that, for someone who purports to be a scientist, Strumia’s use of evidence is shockingly unscientific. His argument is riddled with non sequitur, unjustified assumptions and formulaic prejudice. Apart from everything else I think this is symptomatic of a malaise that is a widespread affliction in the field theoretical physics nowadays, which is worst among string theorists (which Strumia is not), namely a lack of basic understanding of, or even interest in, the proper application of scientific method.

A Bump at the Large Hadron Collider

Posted in Bad Statistics, The Universe and Stuff with tags , , , on December 16, 2015 by telescoper

Very busy, so just a quickie today. Yesterday the good folk at the Large Hadron Collider announced their latest batch of results. You can find the complete set from the CMS experiment here and from ATLAS here.

The result that everyone is talking about is shown in the following graph, which shows the number of diphoton events as a function of energy:

Atlas_Bump

Attention is focussing on the apparent “bump” at around 750 GeV; you can find an expert summary by a proper particle physicist here and another one here.

It is claimed that the “significance level” of this “detection” is 3.6σ. I won’t comment on that precise statement partly because it depends on the background signal being well understood but mainly because I don’t think this is the right language in which to express such a result in the first place. Experimental particle physicists do seem to be averse to doing proper Bayesian analyses of their data.

However if you take the claim in the way such things are usually presented it is roughly equivalent to a statement that the odds against this being a real detection are greater that 6000:1. If any particle physicists out there are willing to wager £6000 for £1 of mine that this result will be confirmed by future measurements then I’d happily take them up on that bet!

P.S. Entirely predictably there are 10 theory papers on today’s ArXiv offering explanations of the alleged bump, none of which says that it’s a noise feature..

 

 

An Open Letter to the Times Higher World University Rankers

Posted in Education, The Universe and Stuff with tags , , , , , , , , on October 5, 2015 by telescoper

Dear Rankers,

Having perused your latest set of league tables along with the published methodology, a couple of things puzzle me.

First, I note that you have made significant changes to your methodology for combining metrics this year. How, then, can you justify making statements such as

US continues to lose its grip as institutions in Europe up their game

when it appears that any changes could well be explained not by changes in performance, as gauged by the metrics you use,  but in the way they are combined?

I assume, as intelligent and responsible people, that you did the obvious test for this effect, i.e. to construct a parallel set of league tables, with this year’s input data but last year’s methodology, which would make it easy to isolate changes in methodology from changes in the performance indicators.  Your failure to publish such a set, to illustrate how seriously your readers should take statements such as that quoted above, must then simply have been an oversight. Had you deliberately witheld evidence of the unreliability of your conclusions you would have left yourselves open to an accusation of gross dishonesty, which I am sure would be unfair.

Happily, however, there is a very easy way to allay the fears of the global university community that the world rankings are being manipulated: all you need to do is publish a set of league tables using the 2014 methodology and the 2015 data. Any difference between this table and the one you published would then simply be an artefact and the new ranking can be ignored. I’m sure you are as anxious as anyone else to prove that the changes this year are not simply artificially-induced “churn”, and I look forward to seeing the results of this straightforward calculation published in the Times Higher as soon as possible.

Second, I notice that one of the changes to your methodology is explained thus

This year we have removed the very small number of papers (649) with more than 1,000 authors from the citations indicator.

You are presumably aware that this primarily affects papers relating to experimental particle physics, which is mostly conducted through large international collaborations (chiefly, but not exclusively, based at CERN). This change at a stroke renders such fundamental scientific breakthroughs as the discovery of the Higgs Boson completely worthless. This is a strange thing to do because this is exactly the type of research that inspires  prospective students to study physics, as well as being direct measures in themselves of the global standing of a University.

My current institution, the University of Sussex, is heavily involved in experiments at CERN. For example, Dr Iacopo Vivarelli has just been appointed coordinator of all supersymmetry searches using the ATLAS experiment on the Large Hadron Collider. This involvement demonstrates the international standing of our excellent Experimental Particle Physics group, but if evidence of supersymmetry is found at the LHC your methodology will simply ignore it. A similar fate will also befall any experiment that requires large international collaborations: searches for dark matter, dark energy, and gravitational waves to name but three, all exciting and inspiring scientific adventures that you regard as unworthy of any recognition at all but which draw students in large numbers into participating departments.

Your decision to downgrade collaborative research to zero is not only strange but also extremely dangerous, for it tells university managers that participating in world-leading collaborative research will jeopardise their rankings. How can you justify such a deliberate and premeditated attack on collaborative science? Surely it is exactly the sort of thing you should be rewarding? Physics departments not participating in such research are the ones that should be downgraded!

Your answer might be that excluding “superpapers” only damages the rankings of smaller universities because might owe a larger fraction of their total citation count to collaborative work. Well, so what if this is true? It’s not a reason for excluding them. Perhaps small universities are better anyway, especially when they emphasize small group teaching and provide opportunities for students to engage in learning that’s led by cutting-edge research. Or perhaps you have decided otherwise and have changed your methodology to confirm your prejudice…

I look forward to seeing your answers to the above questions through the comments box or elsewhere – though you have ignored my several attempts to raise these questions via social media. I also look forward to seeing you correct your error of omission by demonstrating – by the means described above – what  changes in league table positions are by your design rather than any change in performance. If it turns out that the former is the case, as I think it will, at least your own journal provides you with a platform from which you can apologize to the global academic community for wasting their time.

Yours sincerely,

Telescoper

The Origin of CERN

Posted in History, The Universe and Stuff with tags , , , , on September 30, 2014 by telescoper

Since  CERN, the Geneva home of the Large Hadron Collider, is currently celebrating its 60th Anniversary, I thought I would use this organ to correct a widespread misapprehension concerning the the true historical origin of that organization. I have to say the general misunderstanding of the background to CERN is not helped by the information produced locally which insists that CERN is an acronym for Conseil Européen pour la Recherche Nucléaire and that it came into being in 1954. This may be the date at which the Geneva operation commenced, but the organization has a far older origin than that.

CERN is in fact named after the Dorset village of Cerne Abbas, most famous for a prehistoric hill figure called the Cerne Abbas Giant. The following aerial photograph of this outstanding local landmark proves that the inhabitants of Dorset had the idea of erecting a large hardon facility hundreds of years ago…

Physics Nobel Betting

Posted in Science Politics, The Universe and Stuff with tags , , , , , , , on October 7, 2013 by telescoper

I’m back in circulation just in time for tomorrow’s announcement of the 2013 Nobel Prize for Physics. The smart money is going on an award for the discovery of the Higgs Boson, but to whom should it be awarded. Today’s Grauniad summarizes the difficulties thus:

The committee can contrive the wording of the prize to narrow the number downwards and this is likely to happen. The prize could go to François Englert, who published the idea first, and Peter Higgs, who was second, but crucially was first to flag up the new particle. But that would rebuff the trio of Gerald Guralnik, Carl Richard Hagen and Tom Kibble, who developed the theory separately and published just a month after Higgs. The possibility has already caused acrimony among the scientists. Guralnik and Hagen, two US researchers, believe European physicists have conspired to erase their contribution from history.

This doesn’t seem to me to be entirely accurate, though. As far as I understand it, Higgs was the only one of the names above to mention a massive scalar particle, There is, I believe, therefore a strong case that the Nobel Prize should be awarded to Peter Higgs outright. Or if not to him, to some other person called Peter who was born in the North East…

However, I am used to being in a minority of one so there will undoubtedly be many others who feel differently.  Time for a poll! This one is different from my usual ones, in that you are allowed to vote more than once. Please use up to three votes: if you think Peter Higgs should win it outright vote three times for him. If you think it should be a three way split then vote for three different people, etc.

I should say that I don’t think the Nobel Committee for Physics is allowed to make an award to an institution such as CERN, but I’ve left that option in to see whether folks think that tradition should change..

UPDATE: Here are the Thomson-Reuters predictions, including Marcy, Mayor and Queloz for Extra Solar Planets…

 

LHC Lights up NBI

Posted in Art, Biographical, The Universe and Stuff with tags , , , on November 16, 2012 by telescoper

Well, first things first. Congratulations to Dr Sabir Ramazanov on his successful thesis defence today! I’ll perhaps write a bit more about the process in due course.

After the formalities were concluded, however, the committee took a breath of fresh air outside the Niels Bohr Institute where, in the fading November twilight, we were treated to a peculiar light show; a set of small spotlights on the front wall of the NBI building is hooked up directly to the ATLAS experiment on the Large Hadron Collider at CERN so that every time an event registers in Geneva it is displayed almost immediately in public here in Copenhagen. Quite appropriate for a place so steeped in physics history. The resolution of the particle tracks is of course not marvellous, but it’s actually quite a remarkable thing to see, although not all that easy to catch it on camera, especially if you’ve had a couple of glasses of wine!

What’s with the Wang Particle?

Posted in Astrohype, The Universe and Stuff with tags , , , , , , on September 11, 2012 by telescoper

Not long ago a colleague ran into my office all of a flutter and asked me about this new discovery called the “Wang particle” that had been in the media. I’m the one around here who’s supposed to know about particle astrophysics stuff, so I was quite embarrassed that I’d never heard of the Wang particle, although I’ll be delighted if it becomes famous as the name has a great deal of comedy potential.

Anyway, I vowed to find out a little bit about it and finally got around this lunchtime to doing so. It turns out that the story was sparked by press release from the British Science Association which, out of the goodness of my heart, I reproduce below (link added by me).

 A new particle, similar to the Higgs Boson, could provide a clue to one of the greatest mysteries of the Universe.

Dr Charles Wang from the University of Aberdeen believes that a new scalar particle is behind the intense supernova explosions that occur when a star implodes. He presented his work to the British Science Association on Tuesday.

Supernova explosions are the most powerful forces in the universe, second only to the Big Bang.

Once frequent, the energy produced in these explosions is responsible for combining particles to produce all the recognisable elements on earth, providing all the known building blocks of life on earth.

There are still many gaps in our understanding of physics and one of the major blanks is how the implosion of a star subsequently produces an intense explosion.

It is known that as elements are created at the centre of a star, a huge amount of energy is released.  However, it is believed that the conversion of known elements would never produce enough energy to result in an explosion.

Dr Wang’s theory states that “a scalar particle – one of the most elementary types of particles in the universe and similar to the Higgs Boson – is at work within these stars and responsible for the additional energy which causes the explosion to take place.”

The scalar particle would effectively enable the high transfer of energy during a supernova, allowing shockwaves from the implosion of a star to become re-energised and cause an explosion.

A new collaboration between Dr Wang and CERN could provide the equipment to make this theory a reality and demonstrate the existence of the ‘Wang particle’ – or as Dr Wang himself refers to it the ‘scalar gravitational particle’. It is hoped that using the ISOLDE facility at CERN it may be possible assimilate a nuclear reaction that would determine the process of a starburst.

If demonstrated, the existence of the ‘Wang particle’, like the Higgs Boson, would hold major implications for physics, shedding new light on the theory of everything and affecting our understanding of how different physical phenomena interact.

There’s no link to an academic paper with it, which is a bit disappointing, but an older piece in the CERN Courier does provide a reference to the paper, which is

C H-T Wang et al. 2011 Parametric instability induced scalar gravitational waves from a model pulsating neutron star, Phys. Letts. B 705 148

If you’re prepared to shake hands with the Devil that is Elsevier you can find the paper here.

I have to confess that this is a new one on me. I haven’t gone through the paper in detail yet but, at a quick skim, it seems to be based on a variation of the  Brans-Dicke scalar-tensor theory of gravity. It’s probably an interesting paper, and I look forward to reading it in detail on a long flight I’m about to take, but I am a bit mystified as to why it created such a stir in the media. Looks more a result of hype than real significance to me. It certainly isn’t the “new Higgs boson” anyway. Nor is it likely to be relevant in explaining Climate Change. Or am I missing something? Perhaps hot air generated by press releases is responsible for global warming?

Anyone out there an expert on Wang’s work? Care to comment?

Short but sweet – Higgs (1964)

Posted in The Universe and Stuff with tags , , , , on August 31, 2012 by telescoper

In the light of all this Malarkey about the (claimed) discovery of the Higgs Boson at the Large Hadron Collider, I thought you might be interested to see the original paper by Higgs (1964) in its entirety. As you can see, it’s surprisingly small. The paper, I mean, not the boson…

p.s. The paper is freely available to download from the American Physical Society website; no breach of copyright is intended.

p.p.s. The manuscript was received by Physical Review Letters on 31st August 1964, i.e. 48 years ago today.

The Higgs? A Definite Maybe..

Posted in The Universe and Stuff with tags , , , , , , on July 4, 2012 by telescoper

This is really something for expert particle physicists to blog about, but I couldn’t resist saying something about this morning’s dramatic physics news.

Well, after yesterday’s preview here is the actual press release from CERN:

Geneva, 4 July 2012. At a seminar held at CERN1 today as a curtain raiser to the year’s major particle physics conference, ICHEP2012 in Melbourne, the ATLAS and CMS experiments presented their latest preliminary results in the search for the long sought Higgs particle. Both experiments observe a new particle in the mass region around 125-126 GeV.

“We observe in our data clear signs of a new particle, at the level of 5 sigma, in the mass region around 126 GeV. The outstanding performance of the LHC and ATLAS and the huge efforts of many people have brought us to this exciting stage,” said ATLAS experiment spokesperson Fabiola Gianotti, “but a little more time is needed to prepare these results for publication.”

“The results are preliminary but the 5 sigma signal at around 125 GeV we’re seeing is dramatic. This is indeed a new particle. We know it must be a boson and it’s the heaviest boson ever found,” said CMS experiment spokesperson Joe Incandela. “The implications are very significant and it is precisely for this reason that we must be extremely diligent in all of our studies and cross-checks.”

“It’s hard not to get excited by these results,” said CERN Research Director Sergio Bertolucci. “ We stated last year that in 2012 we would either find a new Higgs-like particle or exclude the existence of the Standard Model Higgs. With all the necessary caution, it looks to me that we are at a branching point: the observation of this new particle indicates the path for the future towards a more detailed understanding of what we’re seeing in the data.”

The results presented today are labelled preliminary. They are based on data collected in 2011 and 2012, with the 2012 data still under analysis.  Publication of the analyses shown today is expected around the end of July. A more complete picture of today’s observations will emerge later this year after the LHC provides the experiments with more data.

The next step will be to determine the precise nature of the particle and its significance for our understanding of the universe. Are its properties as expected for the long-sought Higgs boson, the final missing ingredient in the Standard Model of particle physics? Or is it something more exotic? The Standard Model describes the fundamental particles from which we, and every visible thing in the universe, are made, and the forces acting between them. All the matter that we can see, however, appears to be no more than about 4% of the total. A more exotic version of the Higgs particle could be a bridge to understanding the 96% of the universe that remains obscure.

“We have reached a milestone in our understanding of nature,” said CERN Director General Rolf Heuer. “The discovery of a particle consistent with the Higgs boson opens the way to more detailed studies, requiring larger statistics, which will pin down the new particle’s properties, and is likely to shed light on other mysteries of our universe.”

Positive identification of the new particle’s characteristics will take considerable time and data. But whatever form the Higgs particle takes, our knowledge of the fundamental structure of matter is about to take a major step forward.

There’s a hive of internet activity related to this announcement, and I can’t possibly link to all the excellent expert commentary going on, but for details you can do no better that Sean Carroll’s live blog from Geneva or the Guardian’s live blog.

In a nutshell, there’s definitely something in both CMS and Atlas data which, if it really is a new particle,  is definitely a boson and which weighs in around 125 GeV. The two-photon decays are consistent with what a standard model Higgs boson would be expected to produce, for example. The consistency between the two experiments is very compelling.

The overall level of significance is around 5σ. I’ll refrain from making churlish comments about the frequentist language and just say that the LHC certainly seems to have detected something that could definitely be the Higgs. This is genuinely exciting because it has come more quickly than most people expected. That’s a tribute to the LHC teams, I’d say.

However, it isn’t yet proven that the Higgs what this particle is. If it’s a new particle that’s not the Higgs that could be even more interesting. To establish the identity of the particle that has been discovered will require a lot more work,  looking at much more detailed aspects of its behaviour as revealed by collision data. But it’s certainly possible that it is the Higgs, and I venture to suggest that’s what most particle physicists think it is.

So a discovery. A palpable discovery. Now comes the exploration…