Category Archives: CERN

September 2, 2013 · 2:08 pm

COSMO 2013 at Cambridge University

Today was the first day of the COSMO 2013 conference at Cambridge. Walking up the path to the hallowed Department of Applied Mathematics and  Theoretical Physics (DAMTP), I was gripped by my usual fear that I might meet with a frosty reception at the door; “No experimentalists, please!”

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The hallowed halls of DAMTP

But it’s not that sort of conference. COSMO 2013 is a very nice mix of cosmology and particle physics, theory and experiment. You can see the conference poster and programme here.

This morning started with two contrasting plenary talks on particle physics; an experimental talk by Lars Sonneschein, and a more general talk ‘From the Higgs boson to Cosmology’ by well-known CERN theoretician John Ellis.

In his talk ‘Recent Results from the LHC’, Professor Sonnenschein gave a brief overview of recent results at the LHC, from current production rates of top anti-top quarks to the famous discovery of the Higgs boson. Much of this probably wasn’t that new to the audience given the number of Higgs talks last year, but it was good to see up-to-date information on the decay modes and coupling constants for the Higgs.The main point was that with more and more accurate measurements, there is still no evidence yet of any physics beyond the Standard Model, whether one was searching for dark matter, microscopic black holes or indeed supersymmetry (SUSY). On the other hand, there were grounds for good cheer for the experimentalists given the projections Lars gave for increased luminosity at the LHC in the next few years.

John Ellis’s talk took a very different tack. He starting by explaining why a light Higgs mass and weak couplings is a good result for supersymmetry (SUSY can stabilize a light Higgs), giving theorists yet another reason to take the theory seriously, despite the ecent narrowing of windows of possibility at the LHC (at least for minimal models). Professor Ellis then made a connection with cosmology, remarking that basic Wess-Zumino SUSY models can be shown to fit very well with many generic models of inflation;in particular, adding supersymmetry to the mix can give models that fit very comfortably within the recent PLANCK results (some fall well within the dark blue region in the famous Planck figure below). A colleague of a certain age commented to me afterwards  that he isn’t quite reconciled  with the way inflation has become the dominant paradigm in today’s cosmology; for my part, I can never get used to today’s discussions of  supersymmetry in both cosmology and particle physics, having grown up thinking of it as an obscure theory practised only by my father and a few colleagues around the world! Science truly evolves…

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Prof Ellis wearing his Standard Model t-shirt

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Generic SUSY versions of inflation can give models that fall within the most probable region (dark blue)

At question time afterwards, I commented that I was struck by the contrast between the two talks, i.e. the strong motivation for SUSY from theory but the lack of results so far at the LHC, and asked Professor Ellis whether he thought the first evidence for SUSY might indeed come from the cosmic microwave background rather than particle accelerators (I made a mess of the question, nervous for once!). He responded by pointing out that it took 40 years to find the Higgs in particle accelerators, thus we should not be too impatient.  This answer makes a lot of sense to me, I’m a bit dismayed at the way SUSY scepticism has quickly become almost as popular a sport as string theory scepticism. After all, theory is often decades ahead of experiment, particularly in particle physics…

There were two other plenary lectures after coffee, an overview of Dark Matter by Malcolm Fairbairn and a talk on neutrino masses by Silvia Pascoli. They were both excellent talks but there is so much going on I just can’t keep up! Also, Stephen Hawking is sitting three tables away, also working away at a computer – I’m going to tidy myself off to the afternoon sessions before someone mistakes me for a journalist and chases me out of the canteen!

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October 9, 2012 · 8:18 pm

The God particle at Trinity College

On Monday evening, I gave a public lecture on the Higgs boson at Trinity College Dublin. The talk was organised by Astronomy Ireland and I think it was quite a success; 200 tickets were sold and quite a few people had to be turned away.

In the Joly lecture theatre at Trinity College Dublin

How to explain the basics of particle physics to a public audience? As always, I presented the material as a short history of discovery: from the atom to the nucleus,  from protons and neutrons to Gell-mann’s quarks. I also included some theory on the fundamental interactions, right up to the Standard Model,  electro-weak unification and the role of the Higgs field in electro-weak symmetry breaking. Not for the first time, I came away with the impression that the Standard Model isn’t as intimidating for the uninitiated as you might expect. As for physics beyond the Standard Model, the audience seemed to take the hypothesis of grand unification in their stride, and the connection between particle experiments and the early universe struck a chord, as always.

The results  It was a pleasure to present the fantastic results of the ATLAS and CMS teams, first announced at CERN last July. Giving such talks is a lot easier now that the data are publicly available in two beautiful papers on the ArXiv here and here. I gave an overview of the main findings in the context of previous experiments at CERN and at the Tevatron,  and I think the audience got a feel for the historic importance of the result. Certainly, there were plenty of questions afterwards, which continued in the pub afterwards.

The famous bumps ( excess decay events) seen by both ATLAS and CMS at around 125 GeV in the di-photon decay channel

Combined signal (all decay channels) for both ATLAS and CMS

So what about that title? Yes, I did agree to the title ‘The God particle at last’? I am aware that most physicists have a major problem with the moniker; it is sensationalist, inaccurate and incurs a completely gratuitous connection with religion. (Some religious folk consider it blasphemous,  while others misunderstand the term as evidence for their beliefs).

A poster for the talk; naughty

All of this is true, yet I must admit I’ve got to like the nickname; it is catchy and just mysterious enough to cause one to think. I imagine a tired lawyer catching sight of the poster as she walks home after work;  ‘God particle’ might cause a moment of reflection, where ‘Higgs boson’ will not. At least the former expression contains the word ‘particle’, giving the reader some chance to guess the subject. Of course the ‘God’ part is hubris, but is hubris so bad if it gets people thinking about science? Also, I disagree with commentators who insist that the Higgs is ‘no more important than any other particle’. Since all massive particles are thought to interact with the Higgs field, finding the particle associated with that quantum field is of great importance.

So is it found?  CERN Director General Rolf Heuer stated in Dublin, “As far as the layman is concerned with have it. As far as the physicist is concerned, we have to characterize it”. Such characterization has been going on since July. Without question, a new particle of integer spin (boson) and mass 125 +- 0.5 GeV has been discovered. So far, the branching ratios (the ratio of various decay channels to lighter particles) match the prediction of a Standard Model Higgs boson very well. So it looks and smells like a Higgs, and we are all getting used to the idea of the Higgs field as reality rather than hypothesis. (That said, there is still the possibility of spin 1 or 2 for the new particle, but this is not very likely).

All in all, a very enjoyable evening. The slides and poster I used for the talk are available here.  No doubt, some Trinity professors may have been none too pleased to see ‘God particle’ posters in the Hamilton building. Me, I’ve decided I can live with the name if that’s what it takes to get the public excited about particle physics…

Update

Some bloke called Zephyr is upset and accuses me of misleading the public (comments). His point is that I refer to the Higgs as a particle, instead of a quantum field. There is a valid point here; what were once thought of as elementary ‘particles’ of matter are now considered to be manifestations of quantum fields. However, in the business of communicating physics to the public, each physicist must find their own balance between what is accurate and what is comprehensible. My own experience is that people grasp the idea of the Standard Model reasonably well if it’s told as a story of particle discovery (phenomenology). A small amount on quantum theory is ok, but too much soon leaves ’em bewildered. For this reason, I much prefer books like Particle physics: A Very Brief Introduction by Frank Close to books like Higgs: The Invention and Discovery of a Particle  (Jim Baggot)

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July 8, 2012 · 9:19 pm

Hawking, Walton and O’Raifeartaigh

I was surprised and delighted by the photograph below, prominently displayed in this week’s Irish Times magazine. In the accompanying article, journalist Arminta Wallace makes the point that the central figure in the photo is recognizable anywhere in the world, and challenges the reader to name the two Irish scientists flanking him (they are identified later in the piece).

This photo appeared in Saturday’s Irish Times under the caption Science Superstars

The scientist on Hawking’s right is the Irish physicist Ernest Walton, famous for splitting the atomic nucleus in 1932. The Cockroft-Walton experiment was the first successful accelerator experiment (and the first demonstration of E = mc2) and led to a well-deserved Nobel prize. As the prototype of all ‘atom-smashing’ experiments, Walton’s work is extremely relevant to this week’s discovery of the Higgs boson at the Large Hadron Collider (LHC).

The scientist on the left is my late father, Lochlainn O’Raifeartaigh. A senior professor in the School of Theoretical Physics at the Dublin Institute of Advanced Studies (DIAS), Lochlainn was a well known theorist in the field of elementary particle physics. The photo was taken at a conference at DIAS in 1983. I think it’s quite nice – it is not at all staged and one has the impression that the three physicists are enjoying a rare meeting. One sad aspect of the photo is that, even twenty years ago, there is already a marked deterioration in Hawking’s condition. That said, he has outlived the other scientists in the picture…

What would the trio have discussed? What do a leading particle theorist, a cosmologist and a Nobel experimentalist talk about over coffee? My guess is the newly-minted theory of cosmic inflation might have come up. Inflation is a theory that concerns the behaviour of the entire universe in the first fraction of a second, but it borrows heavily from ideas in particle physics. Hence it represents a convergence of cosmology ( the study of the universe at large) with particle physics (the study of the world of the extremely small). Given that the theory had only recently been posited, it’s highly likely that it was discussed by the trio with some excitement. (Of course Walton was an experimentalist but he had a lifelong interest in theory; it is often forgotten that he had a first class degree in mathematics as well as physics and he attended many conferences at the Institute over the years).

Ms Wallace draws a nice connection between the photo and the upcoming Dublin City of Science Festival. There is also a connection with science’s latest triumph, the discovery of a Higgs-like particle. First, Walton’s pioneering accelerator work laid the foundations for today’s experiments at the LHC (see above). Second,  Lochlainn made several important contributions to a theory now known as ‘supersymmetry’.  Supersymmetry is currently being put to the test at the LHC, as experimenters search for the ‘supersymmetric’ particles predicted by the theory. Thus the work of both Irish physicists remains relevant today.

You can read the Irish Times article here and more on Lochlainn’s work here. By coincidence, Lochlainn’s work will be celebrated at an international conference on theoretical physics in Munich next week.

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July 4, 2012 · 12:53 pm

Discovery of the Higgs vs the discovery of the atom

Most people on the planet will hear sometime today that scientists at CERN, the particle physics laboratory in Switzerland, have announced the discovery of a new particle, almost certainly the Higgs boson. ‘Discovery’ is shorthand for 99% confidence level, so this is a great result, coming from two independent experiments at CERN. But what does it all mean?

Below is a script I used for interviews on tv (RTE 1 Six One News) and radio (RE 1 Drivetime); you can see the tv interview here

Q: How important is the discovery, what does it compare with?

It’s not unexpected, but it’s very important. I think it is quite similar to the discovery of the first experimental evidence for atoms by Jean Perrin in 1908 (following a suggestion by the young Einstein). Scientists had long suspected that matter is composed of tiny entities known of atoms but they had never been observed directly. Perrin demonstrated their existence by showing that the random motion of tiny grains of gum in water could be explained in terms of the collisions of the particles with the atoms of the liquid.

Q:What exactly is a Higgs boson, is it like an atom?

We now know that the atom consists of a minute nucleus, with tiny, sub-atomic particles called electrons orbiting the nucleus. The nucleus itself contains other sub-atomic particles of matter called proton and neutrons, themselves made up of even smaller entities called quarks. The full list of the elementary particles of matter is described by the ‘Standard Model of Particle Physics’, the modern theory of the structure of the atom and the forces that hold it together. The Higgs particle doesn’t live inside the nucleus, it is a ‘messenger particle’ predicted by the Standard Model; while all other particles predicted by the model have been detected in experiments in particle accelerators, the Higgs has remained outstanding until now.

Q: And that’s why it’s so important?

Not only that. The Higgs is also of central importance in our understanding of the atom. According to the Standard Model, particles acquire mass as a result of their interaction with the Higgs – or to be specific, their interaction with a certain type of quantum field named the Higgs field (after theoretician Peter Higgs of Edinburgh University). The Higgs particle is simply the ‘messenger particle’ associated with this field.

Q: Why is it sometimes called the God particle?

Most physicists dislike the name, but it is somewhat apt since the field associated with the Higgs particle is thought to endow all other particles with mass. Another reason is that the particle has become something of a Holy Grail in particle physics because it has proved remarkably hard to find over five decades. The discovery of the Higgs boson is an important confirmation that our view of the fundamental structure of matter is on the right track.

Q: How was the particle observed?

At the LHC, two beams of protons are slammed into each other at extremely high energy. Exotic particles are created out of the energy of collision, just as predicted by Einstein (E = mc2). These unstable bits of matter quickly decay into other particles, including Higgs bosons. The Higgs particles themselves then decay into lighter particles in a number of different ways or ‘decay channels’. These particles are detected at the giant particle detectors attached to the beam at CERN – two independent detectors  (ATLAS and CMS) have detected two different decay channels of the Higgs, hence the excitement.

Q: How definite are the results?

Each group is quoting a sigma level of 5, corresponding to 99% certainty. This certainty reflects that a new particle has been found with mass 125 GeV, consistent with a Higgs. However, further work is required to determine whether the particle has other properties consistent with a Higgs.

Q: What comes after the Higgs?

The Higgs particle closes one chapter, but opens another.This is because the Standard Model is known to be incomplete. The properties of the new particle should give great insights into new physics beyond the Standard Model. For example, evidence of more than one type of Higgs particle would be a strong hint of the existence of a whole new family of particles known as supersymmetric particles. The detection of these particles is an important test for unified field theories, theories that suggest that the four fundamental forces of nature once comprised a single force in the infant universe. Indeed, the next round of experiments should give us many important insights into the very early universe because the high-energy conditions resemble those that existed when our universe was very young.

Q: Does the Higgs have a technological application?

No. However, the technologies developed in particle experiments find important application in society. A good example is the use of accelerators in modern medicine. Another is the world-wide web, a software platform first developed at CERN in order to allow scientists to share collision data. The latest innovation is the GRID, the networking of thousands of computers worldwide in order to facilitate the analysis of huge amounts of data emerging from the LHC. Today’s result is a great triumph for the GRID, it is quite amazing that the data was analyzed so fast.

Q: To wrap up; an exciting discovery?

Huge. Expected, but huge. Compares with the discovery of the atom, or putting a man on the moon. The morale of the story is that scientists are like the Mounties – they always get there in the end.

There is a good summary of today’s result in the Guardian here

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July 3, 2012 · 9:57 pm

How about Higgs particle instead of Higgs boson?

Like so many of us physicists, Micheal has a problem with the name ‘God particle’. Scientists have a healthy dislike of hubris (not to mention the needless antagonizing of religious-minded folk) and I am inclined to agree with a ‘do-er’, e.g. a researcher from CMS. Happy Higgs day Micheal, you and yours have done us proud!

Yet as someone who spends a lot of time attempting to engage the public’ s interest in science, I think there are several points worth examining here:

1. The name ‘Higgs boson’ isn’t great either, at least when dealing with the public. It is a classic case of over-specialization, as one immediately has to explain what a ‘boson’ is. Surely ‘Higgs particle’ would be better, as the audience immediately gets a pointer to the area of science under discussion, namely the world of the elementary particles (and whoever heard of the electron fermion?)

2. There is also the problem of priority; as every physicist knows, Professor Higgs was not the only theorist involved in the development of what is now known as the Higgs field (and he predicted the field, not the particle, as he often points out). Many theorists played a part in developing the theory, something that will create something of a Nobel headache – the name won’t help!

3, I still think the moniker ‘God particle’ has some good features; at least it contains the word ‘particle’,  and it is reasonably apt given that (i) the particle is an outstanding piece of the Standard Model (ii) it has an associated field that plays a crucial role in the acquisition of mass and (iii) it has proved remarkably hard to pin down. To put it another way, I suspect the moniker has been helpful in getting across the importance of the particle; without the nickname, I suspect it would have been harder to sustain the media’s attention in the search (how many members of the public were aware of the long search for the top quark?)

4. Could it that the hubris, which we physicists find so annoying, is exactly what it takes to get the public interested? Perhaps science journalists know more than we give them credit for.

Finally, there is the problem of religion/theology. Granted, there are some amongst the devout who take grave offence. Actually, I have never heard a serious theologian criticize or applaud the moniker – they understand the concept of a nickname. Those who can’t see past this may not be worth appeasing.

One obvious comparison here is the nickname ‘big bang’. However, cosmologists hate this moniker for a different reason;it is technically misleading because the theory says nothing about a bang (the name was originally coined by Hoyle as reductio ad absurdum). Yet the expression has been enormously useful at getting across a crude version of the theory. I would much prefer the expression ‘ evolving universe’, but I wonder would the theory have captured the imagination of the public to the same extent. Truth is, I suppose we’ll never know…in the meantime, I think I’ll compromise with ‘Higgs particle’ if I’m interviewed tomorrow!

Update

In the comments section, Sean raises an important point I should have mentioned. A second disadvantage of the term ‘God particle’ is that it encourages those who are inclined to see their particular God in everything. At a time when science is under attack from ultra-conservative religious all over the world (note in particular the attacks on evolution, big bang cosmology and climate science in the US), it is a huge mistake to encourage this sort of sloppy writing. I agree absolutely so, again, I think ‘Higgs particle’ is a reasonable compromise

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November 18, 2010 · 6:43 pm

Antimatter trapped at CERN

The Daily Telegraph has a story today with the headline

Antimatter captured by CERN scientists in dramatic physics breakthrough

accompanied by the picture below and the usual razzmatrazz of antimatter-powered spaceships, antimatter bombs, Angels and Demons etc.

I first came across this strange story on Facebook early this morning and the Daily Telegraph headline iis equally puzzling. As every schoolgirl knows, antimatter is an exotic form of matter made up of particles of opposite electric charge to that of everyday matter (see post on this here). What is puzzling about the story is that physicists have been producing antiparticles in high-energy accelerator experiments since the 1950s and have been able to manufacture whole atoms of antimatter for over a decade now. (Atoms of anti-hydrogen are manufactured in accelerators by allowing anti-protons to capture anti-electons, see here).

About a third of the way down the article in the Telegraph, one discovers the real nature of the breakthrough –  the ALPHA experiment at CERN have reported that they have managed to produce atoms of anti-hydrogen that are relatively longlived (see paper in Nature here). Up to now anti-atoms were extremely shortlived because antimatter is instantly annihilated when it encounters matter (e.g. the container walls). What the Alpha group has done is to trap anti-hydrogen atoms in complex magnetic fields for up to a tenth of a second. Hence the word ‘capture‘ in media headlines, I guess.  It is certainly an important breakthrough as it should enable a detailed study of subtle differences between atoms of hydrogen and anti-hydrogen. (For example, in what way does the spectrum of anti-hydrogen differ from that of ordinary hydrogen?)

The Alpha experiment – don’t try this at home

This is an important area of study because any differences in the spectrum of anti-hydrogen vs ordinary hydrogen could shed light on one of the greatest mysteries of particle physics and cosmology; why is our universe made of matter? What subtle imbalance occurred in the early universe that led to the survival of ordinary matter over antimatter? From the point of view of particle physics, it wll be very interesting to see if CPT symmetry is conserved in the case of anti-hydrogen: if not this has implications for the standard model of particle physics.

Almost everybody in the particle physics universe is blogging on this breakthrough today so I won’t comment further – there is an excellent summary of the experiment on the Symmetry Breaking blog

Update

Kate McAlpine (author of the great LHC rap) has an excellent article on the above in this week’s edition of New Scientist . It’s well worth a look, especially her explanation of how neutral anti-atoms can be trapped in a magnetic field.

Update II

When the film Angels and Demons came out, Dan Brown was widely criticized for suggesting that enough antimatter could be trapped long enough to form a stable bomb (see post and review of A&D here). Looks like Brown wasn’t quite so far off the mark after all – at least about entrapment, if not about a feasible amount of antimatter for a bomb. My guess is that he had some serious discussions with the CERN group, just as he claimed at the time..

Not quite so daft

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September 16, 2008 · 9:42 am

Ireland, CERN and the LHC

There was more coverage of the opening of the LHC in the Irish media over the weekend. My favourite was Ross O’ Carroll Kelly’s piece on the end of the world in The Irish Times on Saturday.

(Three rugger buggers are cowering behind the sofa: “Any last wishes before they hit the button?” – “Yes, I wish I’d studied physics at UCD instead of Orts”).

R.O.C.K. I wish I’d studied physics at UCD instead of Orts

I personally think this sort of coverage gets science into public consciousness far better than any number of earnest articles and letters. More seriously, there was also an excellent article titled ‘Science fact of fiction’ in the same paper on the reporting of ‘nonscience’ such as earth-eating black holes.

Best of all, The Irish Times devoted their Saturday editorial to the LHC, describing the importance of the experiment and bemoaning the lack of participation of Irish scientists due to the fact that Ireland is not a member of CERN. On the same page, they also published a letter of mine on the same subject – not as good as getting an article published, but it’s not every day one’s letter coincides with the theme of the editorial..

Hopefully, all this coverage will help re-ingnite the debate on Irish membership of CERN once more.. .below is my letter

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Madam, – The Irish Times has given exemplary coverage of recent events at Cern, The European Organisation for Nuclear Research, with comprehensive articles, cartoons and other pieces all helping to raise public awareness of this outstanding international scientific centre.

It is a proud moment for Europe, as the experiments at the new particle accelerator will be watched with intense interest by scientists the world over for information on the fundamental structure of matter, and on the evolution of the early universe.

However, as your Science Editor Dick Ahlstrom points out, the participation of Irish scientists in this historic research will be severely limited by the fact that the Republic, almost uniquely among western European nations, is not a member of Cern. This oversight has decimated Irish research in particle physics, despite a proud tradition in the field (Ireland’s only Nobel prize in science was awarded for the splitting of the atomic nucleus by Ernest Walton). More pragmatically, Irish high-tech companies are severely disadvantaged in bidding for the huge contracts available in engineering and information technology at Cern.

So much for our efforts to become a world leader in science and technology. – Yours, etc,

Dr CORMAC O’RAIFEARTAIGH,

Lecturer in Physics, Waterford Institute of Technology

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Update I: it looks like the editorial and my letter have sparked a debate on the topic, there are three letters on the subject in Tuesday’s Irish Times. One of them makes an interesting point:

Madam, – Both you and Dr Cormac O’Raifeartaigh (September 13th) have pointed out that Ireland, almost uniquely among European countries, is not a member of Cern. Surely the reason is simple: the presence of the dreaded word “nuclear” in the organisation’s title…

– Yours, etc,

DAVID SOWBY, Knocksinna Crescent, Dublin 18.

The point here is that Ireland is resolutely anti-nuclear (both power and weapons). Of course, it’s ironic if this is the problem – the name CERN is a misnomer, as it is the physics of elementary particles (not of the nucleus) that is studied at CERN. If you find David Sowby’s suggestion far-fetched consider another letter on the subject in the same paper:

Madam, – Unlike Dr Cormac O’Raifeartaigh (September 13th), I am not at all concerned that Ireland, “almost uniquely among western European nations”, did not pour millions of hard-earned taxpayers’ money into the Cern project.

Whenever I hear the words “nuclear research” other words, such as “Nagasaki” and “Chernobyl” spring to mind and I wish that Ernest Walton and his peers had not “split the atom”. I am sure that if “Irish high-tech companies” have the capability, they will not be “severely disadvantaged in bidding for huge contracts available in engineering and information technology” by our unwillingness to pour millions down the bottomless pit of Cern.

– Yours, etc,

W.J. MURPHY, Malahide, Co Dublin.

I rest my case – perhaps Irish scientists are paying a price for a famous misnomer!

Update II:

Two more letters on the subject in Wednesday’s Irish Times, both of them castigating W.J. Murphy above. Actually, I think they’re a little hard on him – how is Joe Public supposed to guess that the European Organization for Nuclear Research is not involved in nuclear power or weapons? In fairness, it’s a pretty miseading title…here is what one of them said

Madam, – W.J. Murphy (September 16th) says, in a parody of Goering’s remark about Kultur, “Whenever I hear the words ‘nuclear research’ other words, such as ‘Nagasaki’ and ‘Chernobyl’ spring to mind’.

This ridiculous statement demonstrates the widespread ignorance that exists about anything to do with nuclear matters. The words “nuclear research” in Cern’s title refer solely to man’s attempts to discover the basic nature of the matter of which everything in the universe is made. At Cern it has nothing to do with weapons or power.

The comment about Ernest Walton and his peers is merely petty and uneducated. – Yours, etc,

DAVID SOWBY, Knocksinna Crescent, Dublin 18.

True, but a bit harsh, in my opinion

Update III: More letters on the topic in Thursday’s Irish Times. The hapless W. J. Murphy responds to the criticism above by retracting and apologising for the ‘nuclear’ slur, but raises a more difficult issue:

Madam, – David Sowby and George Reynolds (September 17th) are understandably critical of my letter of the previous day, but this is based on a misunderstanding. That is probably my fault: in an attempt to be brief, I grossly over-simplified a complex argument. I would agree with both of their points.

I wonder if they would agree with my substantive point: that the immediate results of the Cern project would not justify the pouring of millions of hard-earned Irish taxpayers money into it and that Irish high-tech companies that have the capability to win contracts in engineering and information technology will not be disadvantaged by this?

I accept that the word “nuclear” means different things to different people. And I should not have referred to Ernest Walton, mea culpa. – Yours, etc,

W J MURPHY, Malahide, Co Dublin

This is the hard question of course: would this money be better spent elsewhere? My own view is that the annual fee (about 10 million) is smaller than some Science Foundation Ireland grants for domestic research – the difference is that CERN is truly world-class work. Just how much it costs to deprive our staff and students the opportunity to work at this level will probably never be known. (We do know for a fact that Irish high-tech companies are seriously disadvantaged in bidding for the most lucrative contracts due to our non-membership, Murphy is quite wrong on this).

Update IV: I have written a new letter to The Irish Times on the above points. They won’t print it, having closed the debate, thus leaving Murphy with the last (incorrect) word. Sigh. I suspect this is why most scientists choose not to get involved in public debate

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September 10, 2008 · 12:17 pm

LHC: D-day at last

So the big news: the first proton beam got all the way around the LHC ring this morning without mishap. Cue much celebration in the CERN control room and around the particle physics community.

There is a live webcast available on the CERN website, although some people are having problems viewing it due to the huge interest. There are also some great updates by physicists at the scene describing the day’s events on blogs such such as US LHC Blog, RESONAANCES, Charm&C, Higgs

The redoubtable Lubos Motl has a great discussion on his blog The Reference Frame explaining why he expects supersymmetry to be seen at the LHC, it’s a very nice piece

For more live postings describing the day’s events, see the list on the international particle physics website interactions.org , it’s almost as good as being there.

P.S. No earth-eating black hole so far…surprise surprise.

Update: the Science Gallery at Trinity College Dublin are celebrating with an open day on the topic, with live feeds, talks and commentary by physicists all day…well worth popping in

Update: a second success… a proton beam successfully completed the loop in the opposite direction in the afternoon, this is way ahead of schedule.

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September 9, 2008 · 2:50 pm

LHC: it’s not the end of the world

The world is not going to end tomorrow (September 10th) and the LHC startup does not constitute a danger to the public, contrary to claims by one or two scientists (non-physicists) that have been widely reported in the media (see here and here for example). Instead, tomorrow marks the beginning of an exciting new era in particle physics – the start of experiments at the world’s most powerful particle accelerator, the Large Hadron Collider at CERN.

Below is part of an article on the LHC that I wrote for an Irish newspaper (they may not use it, thanks to a large number of articles on the same topic by people who know little about the subject). The two main points I wanted to highlight were the safety of the experiment, and the fact that Ireland, almost uniquely among EU nations, is not a member of CERN – despite the fact that our only Nobel prize in science is in precisely this area.

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September 2008 marks an important month for European science. This month, measurements begin at the new “atom-smasher” at CERN, the European Organization for Nuclear Research. Long the jewel in the crown of European science, CERN truly becomes the NASA of the sub-atomic world with the opening of its Large Hadron Collider (LHC), the world’s newest and most powerful particle accelerator.

Situated in a vast 27 km-long tunnel deep beneath the Franco-Swiss border, the new machine at CERN is probably the largest scientific experiment on planet earth. The experiments at the facility will be watched with intense interest by scientists the world over for information on the fundamental structure of matter, and on the evolution of the early universe.

How does it work? Beams of the smallest particles of matter travelling almost at the speed of light will be smashed together in head-on collision. Out of the intense energy of collision, exotic short-lived elementary constituents of matter not seen since the Big Bang will be fleetingly created and tracked in giant particle detectors.

Such experiments offer not only a glimpse of the deep structure of matter, but also of the nature of the forces that hold it together. For example, evidence of the existence of the elusive Higgs boson or ‘God particle’ could offer support for the so-called Standard Model of particle physics, confirming that our view of the origin of mass is correct. Glimpses of exotic entities such as ‘supersymmetric’ particles could reveal deep connections between all the fundamental forces of nature. Other experiments might reveal the true nature of space and time.

Cosmologists hope that the experiments at CERN might offer insight into the formation of the early universe, as the giant collider will achieve energies not seen since the Big Bang. In particular, a glimpse of certain particles could shed light on the nature of Dark Matter, one of the great puzzles of the universe at large.

Is the LHC safe? This question has recently received much attention in the world’s media. In fact, the accelerator is simply a more powerful version of previous machines and constitutes no danger to the public. Rumours that it could create a giant earth-eating black hole arise from a misunderstanding of the physics of black holes (although there is an intriguing possibility that harmless mini-black holes could be created in the experiment).

The 27km tunnel at CERN: experiments will not destroy the earth

Such research into the realm of the sub-atomic might seem of dubious practical application in today’s world. However, the technical spin-offs of experiments at facilities such as CERN are legendary. In 1990, the world wide web was created by CERN physicist Tim Berners-Lee in order to provide a platform for scientists to share and analyse experimental data. Accelerator technology developed at CERN is now routinely used in important medical applications. Most recently, CERN scientists have pioneered the use of GRID computing, a new type of computing that involves the networking of thousands of computers, in order to facilitate the analysis of vast amounts of data that will be collected at the LHC.

CERN is regularly cited as an outstanding example of European collaboration. Created in the 1950s to counter the brain-drain of European scientists to the U.S., it now provides a world-class facility for the scientists of over 20 European nations, while a host of non-European nations such as China Japan, India, the U.S. and Russia all enjoy associate membership. In fact, there are more American particle physicists working at CERN today than in the U.S.

Europe has reason to be proud, but Ireland has not. The participation of Irish scientists in the historic experiments will be severely limited by the fact that the Republic, almost uniquely among EU nations, is not a member of CERN. This omission has decimated Irish research in experimental particle physics, one of the most fundamental fields of the sciences (with the honourable exception of one group at UCD). It has also rendered it almost impossible for Irish engineers and scientists to bid for the large international contracts in high-tech software and hardware projects, a fact that sits awkwardly with our efforts to become a world leader in science and technology.

Strangest of all, Ireland has a proud tradition in this field of science. In 1932, the Irish scientist Ernest Walton and his Cambridge colleague John Cockcroft built the world’s first particle accelerator and used it to split the atomic nucleus, an achievement for which they were awarded the Nobel prize. This work opened up the field of sub-atomic physics, and a version of their machine is used today as a preliminary accelerator in the new facility at CERN.
One wonders what Walton would have made of the Irish absence at CERN at this historic time…

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P.S. Just about every physicist with a blog is writing about the CERN experiments this week, there is a good list of blogs on the topic on the particle physics website interactions.org


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