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Ian Sample - CERN http://www.iansample.com:/site/?q=taxonomy/term/5/0 en A new chapter for Massive http://www.iansample.com:/site/?q=content/new-chapter-massive <p>I spent the months after 4th July 2012 - or discovery day, as history will have it - interviewing many of those most caught up in the hunt for the Higgs boson. I wanted to know how they finally uncovered the particle, how the engineers pushed the Large Hadron Collider as hard as they dared, and how the scientists worked flat out, and against the clock, to pull those gold-plated signatures of the Higgs boson from the scrappy debris of countless subatomic collisions. I wanted to know how they felt as the particle showed its face. They were first to see something new in Nature. Many had worked all their careers for this moment.</p> <p>The stories I heard are the backbone of a new chapter that appears in a re-release of Massive, published first in the US and UK in January 2013. My aim with the fresh material was to recreate the year leading up to the discovery announcement, and those fascinating weeks after, through the eyes of several key players, including the heads of both the ATLAS and CMS detector groups at CERN; the Director-General of CERN; the head of the accelerator team, and, of course, Peter Higgs. Here are the <a href="http:// http://www.amazon.com/Massive-Missing-Particle-Sparked-Greatest/dp/0465058736/ref=pd_sxp_grid_i_2_2">US</a> and <a href="http://www.amazon.co.uk/Massive-Higgs-Boson-Greatest-Science/dp/075354153X/ref=sr_1_1?ie=UTF8&amp;amp;s=books&amp;amp;qid=1274731480&amp;amp;sr=8-1">UK</a> paperbacks:</p> <p><img alt="" src="/site/sites/default/files/Sample-Massive pb.jpg" style="width: 240px; height:300px; border-width: 0px; border-style: solid; float: left;" /></p> <p><img alt="" src="/site/sites/default/files/Massive.jpg" style="width: 240px; height: 300px; float: right;" /></p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>More than anything, as I think back to the interviews, the stories strike me as moving and inspiring. Behind the scenes, away from the cameras and press conferences, this was a collossal effort, a demonstration of extraordinary dedication, and sheer bloody brilliance, by so many scientists and engineers. I already felt this way about many of my interviewees, but time and again, I came away from lengthy conversations with those at the heart of the hunt thinking these are our role models, the people we should praise and aspire to be like.</p> <p>Plenty made me laugh. A Dutch film crew got wind of the discovery and tracked Peter Higgs down in an ancient hilltop village in Sicily, days before the official announcement was made. They scripted several scenes for their film, including one in which Peter sat down with a Dutch physicist who unveiled the crucial results on a laptop. Peter was supposed to look excited, but he didn&#39;t know how to read the plots he was shown. &quot;People have to tell me that&#39;s the bump that&#39;s significant, so it took several takes for me to look happy enough,&quot; Higgs told me.</p> <p>Other stories moved me, and I am not so easily moved. The moment the heads of the ATLAS and CMS collaborations first realised they had a discovery on their hands, the moment the raw plots fell into their hands, was extraordinary to hear about. Excitement, yes, in spades, but there was anxiety, stress and hard graft ahead. CERN could not afford to get this wrong.</p> <p>In the run-up to 4th July, the scientists&#39; data were still hot. At the highest levels of CERN, the fact that the lab had made a discovery had not fully sunken in. There is a lovely few seconds of video you can watch for yourself, and a quote in the new chapter, that demonstrates this. <a href="http://cds.cern.ch/record/1459513?ln=en">Take a look at the CERN seminar from 4th July</a>. Joe Incandela, head of CMS, speaks first. Watch from around 25 mins 40 seconds. You&#39;ll see Joe pause for nearly 10 seconds when he shows a plot with a big Higgsy-bump in it, change the slide, and then say to the audience &quot;I was lost for a moment, excuse me.&quot; I asked Joe about this when I returned to CERN a few weeks later. In replying, he mentions Chiara Mariotti, a colleague who in June had shown him the first plot that suggested they had found the particle: &quot;I realised that everything we had to do was done, from the night Chiara sent me that plot, up until the talk, which I had just finished. We&#39;d made it. I remember giving the talk and at a certain point I showed this plot with a bump and people in the audience gasped. I stood back and thought I&#39;m just going to linger on this for a few seconds. It really hit me then: <em>we&#39;ve really discovered something</em>. I started to enjoy it during the talk. That was the first moment I&#39;d had to relax, and it was the most high pressure talk I&#39;d ever given.&quot;</p> <p>I love that. The fact that they had made a discovery only fully sank in as they gave their talks.</p> <p>There is plenty more in the new chapter. How did CERN leak a video that scooped their own story, the day before the announcement? What happened when a beam of protons hurtled off course and threatened to punch a hole in the Large Hadron Collider? There&#39;s Peter&#39;s explanation for crying as the audience gave Incandela and Fabiola Gianotti, the head of ATLAS, a standing ovation, and his own muted celebration, on a budget flight back home to Edinburgh.</p> <p>The new chapter adds more than 10,000 words to the book. To hear the stories of these amazing people was an unforgettable experience for me, and I hope you&#39;ll enjoy them too.</p> http://www.iansample.com:/site/?q=content/new-chapter-massive#comments CERN Higgs boson Higgs particle Large Hadron Collider Peter Higgs Wed, 13 Feb 2013 23:42:50 +0000 Ian Sample 39 at http://www.iansample.com:/site The fourth man http://www.iansample.com:/site/?q=content/fourth-man <p>Last week I posted a black and white photograph of three young men and a beautiful Sunbeam Alpine convertible taken in 1961 on the campus of Harvard University.</p> <p>I wondered if anyone might recognise the men: two are major characters in Massive and were there right at the start of the story that culminates in the hunt for what became known as the Higgs boson.</p> <p>The third person in the photograph is not in the book, but in many ways should be more recognisable. He went on to hold two of the most senior positions in science in Britain: the government chief scientist and President of the Royal Society.</p> <p>Here is the picture again. As I said <a href="http://www.iansample.com/site/?q=content/three-men-and-car">in my original post</a>, there is a lot to love about the image. What is especially exciting to me is knowing something of the journey the two men who appear here, and in Massive, were about to embark on. It pretty much all began in the year of 1961.</p> <p><img alt="" src="/site/sites/default/files/mghpic1961.jpg" style="width: 635px; height: 350px; border-width: 10px; border-style: solid; float: left;" /></p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>I had planned to write a follow-up blog to reveal the names of the men, but an email arrived the other day that does the job far better than I could ever hope to. The email was from <a href="http://people.ece.cornell.edu/tlfine/">Professor Terry Fine</a>, who recently retired from the School of Electrical and Computer Engineering at Cornell University in New York. He is well placed to say who is who here. He took the photo. It is his car.</p> <p>The email reads:</p> <blockquote><p>There is a fourth person implied by this photo. I took it when my 1960 Sunbeam Alpine was parked behind the Harvard dormitory Conant Hall, near the then Harvard Cyclotron Lab. My long-time friend, Gerry Guralnik, is at the steering wheel. The current Lord May of Oxford is holding up his fingers in an Australian gesture, and Dick Hagen is looking away. Bob May was a postdoc then and the rest of us were grad students.</p> <p>By a strange coincidence, after many decades at Cornell, I moved to a suburb of Rochester, NY, and found that Dick lived only two houses away. Gerry and I have been in good contact over the years.</p> </blockquote> <p>I asked Terry&#39;s permission before posting his email and in his response, he fleshed out the story a little more:</p> <blockquote><p> <style type="text/css"> @font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; }</style></p><p><span style="font-size: 12pt; font-family: Cambria;">I met Gerry in my first semester of graduate school of Harvard. We lived on the same floor of the same Harvard graduate dorm. I then met Dick through Gerry. After two years in grad school and seeing what Gerry was up to I thought of changing direction from electrical engineering to elementary particle theory. I approached Walter Gilbert, Gerry&#39;s thesis advisor, and asked him to be my advisor. Gilbert declined by noting that he himself was switching to biology. I wondered why he would choose to leave such an exciting field, but it did work out rather well for him. </span></p> </blockquote> <p>If you have read Massive, you might recall that <a href="http://en.wikipedia.org/wiki/Walter_Gilbert">Walter Gilbert</a> plays a very interesting role in the story in 1964. I won&#39;t go into that here, but since it is Nobel week, I should however add that Gilbert&#39;s move into biology led to his later sharing <a href="http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1980/">the 1980 Nobel prize in chemistry</a> for DNA sequencing.</p> <p>So there you have it. I know <a href="http://www.brown.edu/Departments/Physics/people/facultypage.php?id=1106970242">Gerry Guralnik</a> and <a href="http://www.pas.rochester.edu/urpas/faculty_page/hagen_c_richard">Dick Hagen</a> as the G and H in GHK, the initials standing for Guralnik, Hagen and Kibble, the three-man team who came up with the theory of fundamental particle masses within weeks of <a href="http://www2.ph.ed.ac.uk/peter-higgs/">Peter Higgs</a> and two others, <a href="http://en.wikipedia.org/wiki/Robert_Brout">the late Robert Brout</a> and <a href="http://www.ulb.ac.be/sciences/physth/people_FEnglert.html">Francois Englert</a> at the Free University of Brussels. <a href="http://www.iansample.com/site/?q=content/higgs-row-and-nobel-reform">(See here for a chronology of their papers)</a>.</p> <p>When people write about the Higgs field or the Higgs mechanism they often seem ignorant to the fact that these ideas came not from Peter Higgs alone, but from six physicists, as near as damn it simultaneously. To pick one person out as responsible for any major push forward in science is almost always a distortion of the truth.</p> <p>I hardly ever see the trio of Guralnik, Hagen and Kibble acknowledged for their work on what is now called the Higgs mechanism, but they were credited, along with Higgs, Brout and Englert, with <a href="http://www.aps.org/units/dpf/awards/sakurai.cfm">the Sakurai prize in 2010</a>.</p> <p>Here is a picture of all three, Guarlnik, Hagen and <a href="http://www3.imperial.ac.uk/people/t.kibble">Tom Kibble (based at Imperial College, London)</a>, on the right. These shots were taken in 1962, when the group was making headway towards their theory of particle masses.</p> <p>I cannot look at this without smiling.</p> <p><img alt="" src="/site/sites/default/files/GHK-1962.png" style="width: 630px; height: 200px; border-width: 10px; border-style: solid; float: left;" /><br /> &nbsp;</p> http://www.iansample.com:/site/?q=content/fourth-man#comments CERN God particle Higgs boson Large Hadron Collider Thu, 06 Oct 2011 22:55:20 +0000 Ian Sample 37 at http://www.iansample.com:/site Massive makes the shortlist http://www.iansample.com:/site/?q=content/massive-makes-shortlist <p>This week I heard the wonderful news that Massive has been shortlisted for the Royal Society Winton science book prize 2011.</p> <p>It is no exaggeration to say the announcement made my year and to see it alongside some titles that truly bowled me over is a real thrill.</p> <p>The <a href="http://royalsociety.org/awards/science-books/shortlist-2011/">Royal Society has posted some information on the shortlist</a> and included some thoughts from the judges on each book. Here&#39;s what they said about Massive:</p> <p>&ldquo;An extraordinary book that tells the real human story behind one of the biggest science adventures of our time, managing to translate the complex concepts of particle physics into a real page-turner.&rdquo;</p> <p>If nothing else this has given me a confidence boost and helped me take seriously my meandering plans for a second book. All I will say about the embryonic idea I have been kicking around is that I have been researching it for six months or so and have yet to fall out of love with it. And that I have decided against calling it Missive.</p> <p>The other titles on the shortlist are:</p> <p><em>Alex&#39;s adventures in numberland</em> by Alex Bellos</p> <p><em>Through the language glass: how words colour your world</em> by Guy Deutscher</p> <p><em>The disappearing spoon</em> by Sam Keane</p> <p><em>The wavewatchers companion</em> by Gavin Pretor-Pinney</p> <p><em>The rough guide to the future</em> by Jon Turney</p> <p>I know what you&#39;re thinking. Where is Rebecca Skloot&#39;s <a href="http://rebeccaskloot.com/the-immortal-life/">The Immortal Life of Henrietta Lacks</a>? I have no idea. I can only imagine that it wasn&#39;t entered.</p> <p>The Royal Society kindly included some bookies&#39; odds and have Massive down at 5-1, which in a six title shortlist brings to mind a memorable quote from Dumb and Dumber: <a href="http://www.imdb.com/title/tt0109686/quotes">&quot;So you&#39;re saying there&#39;s a chance...Yeah!&quot;</a></p> <p>At New Scientist, where I began my life as a reporter, <a href="http://www.newscientist.com/blogs/culturelab/2011/09/royal-societys-top-6-books-of-2010.html">they have written up the shortlist with some thoughts from their own reviews</a> of the books above, including Massive. I am ashamed to say it made me grin to see that Massive wins on size if nothing else.</p> <p>My agent wrote a little ditty on the shortlist too and used <a href="http://www.sciencefactory.co.uk/content/news.php?nid=210">a horrific pun in the headline</a>. You can tell <a href="http://www.nature.com/nature/journal/v432/n7019/abs/432803a.html">he used to work at Nature</a>.</p> <p>I wish all of the shortlisted authors the best of luck and hope to meet some of them in London later in November when the winner is announced.</p> <p>But back to what I should call my next book. There&#39;s another Ian Sample in the world who is, or was, an American footballer and wrote a book called <a href="http://www.amazon.com/Once-Warrior-J-Ian-Sample/dp/0979064791">Once a Warrior</a>. I bought it secondhand off Amazon for fun. It made me wonder if I should write a self-help title for the anxious called &quot;Once a worrier&quot;.</p> <p>Enough.</p> http://www.iansample.com:/site/?q=content/massive-makes-shortlist#comments CERN Higgs boson Large Hadron Collider royal society winton science book prize Thu, 29 Sep 2011 16:36:23 +0000 Ian Sample 35 at http://www.iansample.com:/site The final hiding place? http://www.iansample.com:/site/?q=content/final-hiding-place <p>The Large Hadron Collider has left little room for the Higgs to hide after a spectacular tour de force that kicked off the summer conference season.</p> <p>Among particle physicists there is a palpable feeling that, one way or another, we will soon know whether the famously elusive particle exists or not. The answer might well set the course of physics for decades to come.</p> <p>The summer meetings are always worth watching: these are major dates on the scientific calendar when the world of high-energy physics gathers to announce its latest findings. The work can sound arcane at first pass, but the big discoveries made public at these meetings can go on to earn Nobel prizes.<br /> &nbsp;<br /> The season began last week, with scientists heading to France for <a href="http://eps-hep2011.eu/">the Europhysics Conference on High Energy Physics in Grenoble</a>. If anything was clear beforehand, it was that the Large Hadron Collider was performing well beyond expectations.</p> <p>Even with that in mind, the results from the world&rsquo;s most powerful particle collider were nothing short of breathtaking. In one fell swoop, the LHC had searched and dismissed a vast range of masses that the Higgs particle - as described by the Standard Model at least - might take. If the particle exists in this form, the likelihood now is that it lurks in a low and narrow range of masses that will be fully explored within months.</p> <p>The hunt for the Higgs at the LHC plays out almost exclusively in two general-purpose detectors called Atlas and CMS. The search proceeds by smashing protons into one another and looking for hints of the Higgs in the debris of those collisions. The Higgs particle, if real, has only a fleeting existence, and decays immediately into other well-known particles. Which ones depend mostly on the mass of the Higgs particle, which nobody yet knows.</p> <p>Back in 2000, the LHC&rsquo;s predecessor at CERN,<a href="http://public.web.cern.ch/public/en/research/lep-en.html"> the Large Electron Positron collider</a>, ruled out a Standard Model Higgs boson below around 115 GeV (gigaelectron volts). Since then the Tevatron has excluded the Higgs particle between 157-173 GeV. Indirect evidence &ndash; that is inferring the Higgs mass from precision measurements of the top quark and so on &ndash; suggest the Higgs is no heavier than 185GeV.</p> <p>So what did the LHC detector groups find?</p> <p>Atlas ruled out a Standard Model Higgs boson from <a href="http://indico.in2p3.fr/contributionDisplay.py?contribId=299&amp;sessionId=6&amp;confId=5116">155-190 GeV and 295-450 GeV</a>. Meanwhile, CMS excluded the range <a href="http://indico.in2p3.fr/contributionDisplay.py?contribId=189&amp;sessionId=6&amp;confId=5116">149-206 GeV and 300-440 GeV</a>.</p> <p>This means that if the Higgs boson is the kind described by the Standard Model &ndash; that is, the simplest possible - it probably lies in the region 115 &ndash; 149GeV. It will take more data to scour this region for signs of the Higgs.</p> <p>These results were impressive enough, but there was more to the story last week. Atlas reported a bump in its data &ndash; due to an apparent excess of particle decays &ndash; in the region 120GeV to 140GeV. That excess might just be due to the Higgs particle, but the strength of the signal was too low to claim official evidence.</p> <p>The Atlas bump was intriguing in itself, but signals like these can easily be caused by statistical fluctuations in data or poorly modelled backgrounds. What makes the bump slightly more exciting is that the CMS detector saw a similar, though smaller bump in the same region. This is tantalising stuff, but it helps to keep a level head.</p> <p>There is a chance that both detectors have seen their first glimpse of the Higgs particle, but this is only one possibility. The detectors model their backgrounds &ndash; that is the decays from other particles &ndash; in similar ways, so if the modelling is flawed, both detectors could see a spurious bump in the same place. In short, this is more interesting than exciting.</p> <p>I tried to write about this potential glimpse of the Higgs particle in the Guardian, but what appeared was a minor car crash. The headline, &ldquo;<a href="http://www.guardian.co.uk/science/2011/jul/22/cern-higgs-boson-god-particle">Cern scientists suspect glimpse of Higgs boson God particle</a>&rdquo;, was only the most cringe-inducing problem, and managed to be simultaneously wrong and embarrassing. Hardly anyone outside a newsroom likes the phrase &ldquo;God particle&rdquo;. (<a href="http://www.iansample.com/site/?q=content/god-physics-and-book-titles">More on that here.</a>) More seriously, no-one I spoke with at Cern suspected they had glimpsed the Higgs: there are simply too many other explanations right now. These needless exaggerations grate. There is a chance England will win the next World Cup, but I don&#39;t suspect it will happen.</p> <p>If you have never followed the hunt for the Higgs, now is a good time to start. By the end of August, Atlas and CMS plan to combine their results using data from more collisions. If the low mass excesses get bigger, it will be hard not to start wondering whether the Higgs has finally begun to show itself. We should hear more at <a href="http://www.tifr.res.in/~lp11/">the Lepton-Photon conference in Mumbai</a>.</p> <p>And what then? When I interviewed Steven Weinberg, the Nobel prize-winning physicist at the University of Texas at Austin, during my research for Massive, I asked him what it would mean for physicists to find the Standard Model Higgs boson. He replied that rather than pull physics out of the doldrums, it would plunge physics into the doldrums. The problem is this: Find the single SM Higgs boson and the Standard Model becomes a jigsaw complete. As wonderful as that would be, it gives us no new clues as to what lies beyond the Standard Model. And something must. Much better would be to find more than one Higgs.</p> <p>One of the most popular theories for taking physics beyond the Standard Model is supersymmetry, which says that each type of known particle has a heavy and as-yet-undiscovered twin. There is a beauty to supersymmetry, but its real appeal is in describing gravity and the other three known forces of nature. It also predicts more than one kind of Higgs particle. But results released from the LHC at Grenoble did nothing to bolster confidence in supersymmetry. They ruled out supersymmetric particles below 1.2Tev (teraelectron volts), putting the squeeze on supersymmetry itself.</p> <p>What is amazing about all of this is that so much has come so quickly from the Large Hadron Collider. There is more to come. The Large Hadron Collider has begun to wield its might.<br /> &nbsp;</p> http://www.iansample.com:/site/?q=content/final-hiding-place#comments CERN Higgs boson Higgs particle Large Hadron Collider Sun, 24 Jul 2011 20:53:57 +0000 Ian Sample 34 at http://www.iansample.com:/site To be a great physicist http://www.iansample.com:/site/?q=content/be-great-physicist <p>I never met <a href="http://www.ulb.ac.be/sciences/physth/people_RBrout.html">Robert Brout</a> but on 4th June 2007 I interviewed him over a scratchy Skype line at his home in Brussels about his part in what has become the story of the Higgs boson. He was joined by <a href="http://www.ulb.ac.be/sciences/physth/people_FEnglert.html">Francois Englert</a>. Together they wrote <a href="http://prl.aps.org/abstract/PRL/v13/i9/p321_1">the first paper to describe how particle masses might arise</a> from the kind of field <a href="http://www2.ph.ed.ac.uk/peter-higgs/">Peter Higgs</a> is now famous for.</p> <p><img alt="" src="/site/sites/default/files/large_brout64.jpg" style="border-width: 20px; width: 190px; height: 190px; float: right;" />When I began work on <em>Massive</em> I arranged to visit Brout and Englert in Belgium. The day I arrived, in June 2009, Robert wasn&#39;t well enough to make it. I sat in Englert&#39;s office at the Free University of Brussels and talked through the pair&#39;s history: how they came to know each other, how they worked at Cornell University but returned to live in the same city, to work at the same university, where they first circled and then cracked the problem of particle masses.</p> <p>I was sorry not to meet Brout. When I interviewed the pair in 2007 I laughed more than I had in a long time. These two men, Brout the mentor of Englert, seemed to me to enjoy a depth of friendship that made the word inadequate. It was less an interview, more an eavesdropping on a conversation between the two. They finished one another&#39;s sentences, poked fun at themselves, and described their feelings on events not so much to me, but to each other.</p> <p>Robert Brout died on 3rd May 2011. Since hearing the news, I wanted to go through my old interview notes and share some of his comments from our conversation. There was one sentence in particular that has lodged in my mind.</p> <p>You might know that the mechanism for generating particle masses can be traced back to 1960 and work by <a href="http://news.uchicago.edu/profile/yoichiro-nambu">Yoichiro Nambu</a>, who framed the issue in terms of superconductor theory. I will spare you the details, though the book will not, but the link is that when a photon moves into a superconductor, it becomes massive and as a consequence doesn&#39;t travel very far.</p> <p>Brout and Englert seized on Nambu&#39;s idea and developed it. Brout told me that in 1963 he was &quot;completely clear that it was possible to generate mass with some kind of scalar particle&quot;, i.e. something like the Higgs boson. &quot;But it took some time to have the complete vision,&quot; he said.</p> <p>The two physicists spent months checking their work for errors and for good reason. They were outsiders when it came to particle physics and the idea they were playing around with was radical. Come the spring of 1964 they had failed to find any mistakes and were confident the work was sound.</p> <p>Here&#39;s what Brout said of that time, though as you will see, he is talking to Englert too.</p> <blockquote><p>We were having a beer together on a terrace overlooking a park and we were both very excited. The fact that we could account for the masses of some of the gauge particles, but keep the photon massless, the fact we could realise this excited us terribly. I thought, Francois, that for the first time in my life, I felt what it might be to be a great physicist.</p> </blockquote> <p>For the first time in my life, I felt what it might be to be a great physicist.</p> <p>That line has stuck with me. I can remember how he said it. It made me think of the greats and imagine, hopelessly, but as best I might, the heady feeling of knowing for an instant that you have seen deeper into nature than anyone else.</p> <p>There were six physicists who described in 1964 how particles might get their masses. Brout and Englert were the first. Sadly all six have never met as a group and any chance of that happening is now gone. The closest they came was in 2010, <a href="http://www.guardian.co.uk/science/blog/2009/oct/05/sakurai-prize-brout-englert-guralnik-hagen-kibble-higgs-god-particle-higgs-boson">when all six shared the Sakurai prize for theoretical physics</a>. Only Peter Higgs was missing from the award ceremony.</p> http://www.iansample.com:/site/?q=content/be-great-physicist#comments CERN francois englert God particle Higgs boson Large Hadron Collider robert brout Sat, 14 May 2011 13:39:16 +0000 Ian Sample 32 at http://www.iansample.com:/site Another one bites the dust http://www.iansample.com:/site/?q=content/another-one-bites-dust <p>And so to the media scramble at Easter that scientists at the Large Hadron Collider had finally glimpsed the Higgs boson, or at least its fleeting footprint: a flicker of light in the giant Atlas detector.</p> <p>You&#39;ll recall what happened. <a href="http://www.math.columbia.edu/~woit/wordpress/?p=3643">A leaked note from the Atlas collaboration</a> pointed to an excess in one of the ways a Higgs particle might decay - that is, into two high energy photons. An excess means extra particles coming from somewhere beyond the Standard Model, and in this case, potentially from the Higgs (which is highly unstable) decaying into particles of light.</p> <p>The internal note was just that, a very preliminary finding, and it was posted to a blog before it had been scrutinised in any serious detail.</p> <p>This was not the first time researchers (if only a handful) had got their hopes up that a discovery was at last in the offing. Nor was it the first time there were serious doubts that the Higgs had suddenly popped up and been measured. <a href="http://www.guardian.co.uk/science/2011/apr/28/higgs-boson-rumour-cern-lhc">See here for some of the previous incidents and a few early doubts raised over the latest Higgs signal</a>.</p> <p>Internal notes like these are not exceptional and there is a well-worked process for assessing them. The ones that point to evidence of the Higgs boson (and it&#39;s arguable that this one did) go to a bunch of specialists called the Higgs working group, who look at the claims in detail. If they are happy the analysis is sound, the abstract goes out to the whole Atlas collaboration for further scrutiny. That is some serious intellectual clout being brought to bear.</p> <p>Since the fuss at Easter, researchers at Cern have been studying the latest claim. And what have they found? The answer, as you might have guessed, is nowt. In the latest analysis of Atlas data, there was no sign of a Higgs particle decaying into high energy photons at a mass of 115GeV (the mass indicated in the original note), or any other mass for that matter. The conclusion of the latest note, published earlier today, is this:</p> <p><strong>&quot;No excess is observed, neither with the analysis criteria described in this note nor with other selections studied.&quot;</strong></p> <p><a href="https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/CONFNOTES/ATLAS-CONF-2011-071/ATLAS-CONF-2011-071.pdf">Read the full conference note here</a>.</p> <p>The knockdown doesn&#39;t come as a surprise and in these days of thousands-strong collaborations, scientists&#39; blogs and a genuinely enthused media, nor does the mass coverage of the non-sighting. There will be more, and we can certainly expect some fun in the run up to the summer conferences. <a href="http://www.economist.com/node/18618015">Or as the Economist put it, &quot;expect plenty more herrings, red or otherwise.&quot;</a></p> http://www.iansample.com:/site/?q=content/another-one-bites-dust#comments CERN God particle Higgs boson Large Hadron Collider LHC Sun, 08 May 2011 11:56:10 +0000 Ian Sample 31 at http://www.iansample.com:/site The year of the Higgs http://www.iansample.com:/site/?q=content/year-higgs <p>Things are looking good at Cern. <a href="http://lhc.web.cern.ch/lhc/">The Large Hadron Collider (LHC)</a> is back in business and for the first time, there is a real sense that major discoveries are within reach.</p> <p>It seems as good a time as any to zip through some of the basics surrounding the hunt for the Higgs boson. To cut to the chase (and barring any mishaps) the LHC is likely to get at least a sniff of the Higgs particle later this year, with probable confirmation coming next year. But for the next 10 months this is still a two horse race. <a href="http://www-bdnew.fnal.gov/tevatron/">The world&rsquo;s second most powerful collider, the Tevatron at Fermilab in Illinois</a>, may glimpse the missing boson before it closes down for good at the end of the year.</p> <p>I didn&rsquo;t write about the <a href="http://www.guardian.co.uk/science/life-and-physics/2011/jan/10/1">US Department of Energy&rsquo;s decision to switch off the Tevatron this year</a>, instead of running on for three more as the lab had hoped. I spoke to people on the committee involved and there was certainly disappointment in some quarters. The announcement was disheartening for a country of America&rsquo;s means, but the bigger issue now has to be whether the US has a good enough strategy in place to inspire its next generation of high-energy physicists. <a href="http://www.fnal.gov/pub/science/experiments/intensity/">That is another story</a>.</p> <p>I&rsquo;ll cover some simple stuff in the paragraphs below, including how a collider makes particles; how the Higgs boson might be made; what it might look like, and how do you claim an official discovery. Then I&rsquo;ll lay out the status of the search to date and some future prospects.&nbsp;</p> <p>In the olden days, <a href="http://www.aip.org/history/lawrence/epa.htm">accelerators sent particles slamming into targets in the hope of smashing atoms into pieces and revealing their constituents</a>. Hence the nickname &ldquo;atom smasher&rdquo;. Colliders like the LHC do things differently. They slam particles together in head-on collisions to produce intense and concentrated flashes of energy. The energy released in each collision is available to make particles, in line with Einstein&rsquo;s infamous equation of mass and energy. Some of the energy of the collision effectively condenses into matter.</p> <p>The LHC was designed to accelerate protons (which are simply hydrogen atoms with their electrons ripped off) and collide them at energies of 14 teraelectronvolts (TeV). One electron volt is the kinetic energy an electron gains when it is accelerated by a potential difference of one volt. Physicists use prefixes to refer to large energies, such as kilo (1000), Mega (1 million), giga (1 billion) and Tera (1 trillion). The mass of <a href="http://www.symmetrymagazine.org/cms/?pid=1000631">a Z boson </a>is around 91GeV/c2, so a collision needs to liberate at least this much energy to make one.</p> <p>Although the LHC was built to crash protons together at 14TeV, there is far less energy available in each collision to make new particles. The machine is running at half energy at least until the end of 2011, meaning the total energy is only 7TeV. But that is not the only issue. More important is that inside the LHC, collisions are not between protons themselves, but their constituents. Each proton is made up of three quarks and three gluons and the collisions are between these. So when two protons crash into each other, it is actually the gluons and quarks that hit each other. This matters because the energy is shared out among the constituents. So if two protons collide at 7TeV, the maximum amount of energy released when the bits inside hit one another is only around 1TeV.</p> <p>So how might the Higgs boson be made in a collider? This depends on many things. In the LHC and the Tevatron, two colliding gluons can produce a Higgs particle. Once made, the Higgs boson doesn&rsquo;t just sit there waiting to be discovered. It is highly unstable and decays immediately into more familiar particles. Which ones depend on how much mass &ndash; and so how much energy - the Higgs particle has. In the LHC, one option is for the Higgs to decay into two high-energy photons. <a href="http://www.guardian.co.uk/science/2011/apr/28/higgs-boson-rumour-cern-lhc">I&rsquo;ll be blogging about the fuss over a potential signal in this decay mode pretty soon</a>.</p> <p>I&rsquo;ve had conversations with non-scientists (let&rsquo;s call them the Guardian newsdesk) about the LHC during which it&rsquo;s become clear they don&rsquo;t grasp why results can be a long time in coming from a particle collider. The confusion is understandable. Plenty of people are used to school experiments where an instrument is switched on, you take a measurement and get the answer. Life is not so easy with colliders. Thanks to the uncertainties of quantum mechanics, you never know whether or not a particle will be created in a collision. The best you can do is work out the probability, analyse countless collisions, and look for an excess in the number of particles the Higgs, in this case, decays into.</p> <p>You can look at this in another way. Suppose the LHC was colliding wallets instead of protons. Most of the time, the debris from the collisions would include some loose change, a few notes and some bankcards. The problem is that even when a Higgs is made, it immediately decays into familiar stuff &ndash; more loose change, notes and bankcards in this analogy. So what you look for is the right amount of extra debris that you&rsquo;d expect were the Higgs particle popping into existence and immediately decaying.</p> <p>Physicists rank the strengths of these excesses in standard deviations, denoted by the greek letter sigma. To claim a cast-iron discovery takes a five sigma signal, which means the surfeit of decay particles you measured has less than a one in a few million chance of being a statistical fluke. Officially, &ldquo;evidence&rdquo; means at least a three sigma signal.</p> <p>So where is the Higgs search at right now? In 2000, <a href="http://public.web.cern.ch/public/en/research/lep-en.html">Cern&rsquo;s Large Electron Positron (LEP) Collider </a>ruled out a Higgs below 114.4GeV, but saw what might have been signs of the Higgs at a slightly greater mass shortly before it closed down. Since then, the Tevatron has ruled out a range of masses, from 157GeV to 173GeV. Indirect measurements of the Higgs mass pretty much rule out the particle (that is, with 95% confidence) above 185 GeV.</p> <p><img alt="" src="/site/sites/default/files/higgssearch.jpg" style="border-style: solid; border-width: 5px; width: 374px; height: 212px; margin-left: 5px; margin-right: 5px; float: left;" />In January, Rolf Dieter Heuer, Cern&rsquo;s Director General, gave a talk to personnel and among other things, discussed the prospects for a Higgs discovery. <a href="http://indico.cern.ch/conferenceDisplay.py?confId=116025">You can see the whole presentation here</a>. Slide 17 is key. Here, the DG says the Tevatron can pretty much rule out the Higgs (if it doesn&rsquo;t exist) between a mass range of 114 to 185GeV by the end of the year. In that period, the collider could see three sigma evidence for a Higgs particle with a mass of 115 GeV or somewhere in the range from 150 to 180GeV.</p> <p>But what about the LHC? A more detailed prediction is given on slide 17, but one fairly optimistic scenario (one that sees the machine collect 2.5 inverse femtobarns of data at eight teraelectronvolts) suggests the LHC could exclude the Higgs if it doesn&rsquo;t exist iver essentially the entire mass range; find three sigma evidence for a Higgs weighing 123 to 530 GeV, and an all important five sigma discovery if the Higgs lies at 138GeV to 220GeV. The Higgs particle may well weigh less than 123GeV and not reveal itself at the LHC until 2012.</p> <p>So what next? Neither Cern nor Fermilab will sit on a major discovery should one appear in their data.&nbsp; Large collaborations leak like sieves and any news will likely emerge as rumours on the physics blogs before a research paper is posted on the arxiv and any press conference called. Barring any surprises, expect the next news to be unveiled in the summer, at <a href="http://eps-hep2011.eu/">the European Physical Society High Energy Physics meeting in Grenoble at the end of July</a>.<br /> &nbsp;</p> http://www.iansample.com:/site/?q=content/year-higgs#comments CERN Fermilab God particle Higgs boson Large Hadron Collider Tevatron Wed, 27 Apr 2011 21:43:41 +0000 Ian Sample 30 at http://www.iansample.com:/site God, physics and book titles http://www.iansample.com:/site/?q=content/god-physics-and-book-titles <p>There are ways to open a talk and ways not to open a talk and in the summer it wasn&rsquo;t so clear which I&rsquo;d picked when I stood up to give a lecture on Massive at the <a href="http://www.edbookfest.co.uk/">Edinburgh International Book Festival</a>. It went something like this. No. It went exactly like this. &ldquo;I must be the first author to speak at an international book festival who winces at the title of his own book.&rdquo;</p> <p>The audience must have been a friendly bunch because they were good enough to laugh and forget for a moment all those other authors who surely cringed at the titles of their own books. The room was dimly lit but I could hear them well enough. Behind me, at the back of the stage, the UK cover of my book was projected onto a large screen and the words stood out in bold against a glowing white background: &ldquo;Massive: the hunt for the God particle.&rdquo;</p> <p><img alt="" src="/site/sites/default/files/Massive RGB.jpg" style="margin: 5px; width: 100px; height: 140px; float: left;" /> There&rsquo;s nothing wrong with Massive as a title. It so happens that I love it. The book tells the story of the science and scientists behind the Higgs field and the race to find the elusive Higgs particle. The field is thought to give mass to elementary particles, that is, to make them massive. Read the book and you will see that this is profoundly important. But the title is more than a geeky pun. Look at the scale of the hunt for the Higgs particle: its duration, the number of people involved, the cost and the size of the machines built to do the job. Look at how important discovering the particle has become to physics. Look at the media hype that breaks out periodically when the particle hits the news. I&rsquo;d say massive is about right.</p> <p>You might have guessed that the root of my unease was not so much the title as the subtitle, and more specifically, the last two words: &ldquo;God particle.&rdquo; The name is deeply unpopular with physicists and for good reason. What I wanted to tell the audience in my opening line, I suspect, was that I shared scientsts&rsquo; contempt for the monicker. But not enough to stop me using it, at least not in the UK.</p> <p>This week, on 2nd November, the US version of Massive hits the shelves. The book is more or less the same as the<img alt="" src="/site/sites/default/files/MassiveUSCover.jpg" style="margin: 5px; width: 123px; height: 148px; float: right;" /> UK version (there are some differences I&rsquo;ll explain later), but the most visible change is with the subtitle. The God particle is done away with. In the US, the book is called &ldquo;Massive: The Missing Particle That Sparked the Greatest Hunt in Science&rdquo;. <a href="http://www.perseusbooksgroup.com/basic/book_detail.jsp?isbn=0465019471">This was the US publisher&rsquo;s idea</a> and I embraced it wholeheartedly. Apart from simply liking it, I took it as an opportunity to see how people reacted to the different versions: God particle vs no God particle. I expected criticism in the UK. I anticipated testy reviews. I imagined a few letters from religious-minded people.</p> <p>Let&rsquo;s get one thing straight. The &ldquo;God particle&rdquo; is not my phrase. <a href="http://nobelprize.org/nobel_prizes/physics/laureates/1988/lederman-autobio.html">The Nobel prize winning physicist and former director of Fermilab, Leon Lederman</a>, hit on the nickname in his book of that name in 1993. Lederman justifies his choice in various ways: that his publisher insisted no-one had heard of Higgs; that the particle deserved elevation because it was crucial to our understanding of matter; and that his preferred phrase, the &ldquo;Goddamned particle&rdquo; (on account of its elusive nature) was over-ruled. Whatever the reason, the media seized upon it and the name stuck.</p> <p>God has a habit of cropping up in physics. <a href="http://scienceworld.wolfram.com/biography/Einstein.html">Einstein was perhaps the most relentless</a> in churning out references to God, or &ldquo;the Old One&rdquo;, and I won&rsquo;t plough through them all here. <a href="http://www.npr.org/blogs/13.7/2010/09/08/129736414/hawking-and-god-an-intimate-relationship">Stephen Hawking dropped the G-word</a> into &ldquo;A brief history of time&rdquo;, with his now infamous &ldquo;mind of God&rdquo; line. Then, in 1992, <a href="http://www.nytimes.com/2006/10/04/science/04nobel.html">George Smoot announced the discovery of faint irregularities in the ancient radiation still reaching us from the Big Bang</a> and said, &ldquo;If you are religious, it is like looking at God.&rdquo;</p> <p>None of the above references to God were meant to imply the existence of a supernatural being. For God read nature, or the laws of physics, or the origin of the cosmos. When Einstein said: &ldquo;He does not play dice&rdquo;, he was doubting that quantum randomness lay at the heart of nature. When Hawking clarified what he meant by &ldquo;the mind of God&rdquo;, he said: &ldquo;If we discovered the complete set of laws and understood why the universe existed we would be in the position of God&hellip; One could define God as the embodiment of the laws of nature.&rdquo; Similarly, Smoot elaborated: &ldquo;It really is like finding the driving mechanism for the universe, and isn&rsquo;t that what God is?&rdquo;</p> <p>But there is a problem. God works as a metaphor only if the meaning is clear. In the case of Einstein, Hawking and Smoot, there is little room for doubt. We get what they mean. That, I suspect, is not true with the &ldquo;God particle&rdquo;. The first time I heard it, I had no idea what to make of it. We can bolt on meaning after the event, and we might even find it justifiable, but at heart it is unclear and an unconvincing nickname. This, I think, is why physicists hate it so much. Stripped of any greater meaning, the &ldquo;God particle&rdquo; becomes a cheap shot, a PR stunt and nothing more.</p> <p>So why did I still use &ldquo;God particle&rdquo; in the subtitle of my book in the UK? Here&rsquo;s why. By the time I wrote the book, I had read that phrase more times than I care to remember. Not one of the countless physicists I interviewed for the book said anything nice about it. I don&rsquo;t like it myself. But the thing is, that nickname was always there, and a necessary issue to explore in the conversations I had. The bottom line is that the God particle phrase is an indelible part of the story, and one that comes from within the scientific community. I used it because I didn&rsquo;t want to shy away from it. Having done so in the UK, I was more than happy not to in the US.</p> <p>Then the emails and letters arrived. The first was from Lord Rees, president of the Royal Society. &ldquo;Really nicely done,&rdquo; he said of the book, before unleashing the jab: &ldquo;My only regret is that you&rsquo;re perpetuating the silly phrase &ldquo;God particle&rdquo;. He went on to say it might help with sales. I disagree. My own view is people in Britain (where God is increasingly struggling for followers) will be put off by the subtitle, not attracted.</p> <p>The letters were more bizarre. One man wrote to tell me he had witnessed miracles and that these might have something to do with the Higgs boson. He included a photo of himself. Another person wrote to me with something quite extraordinary. He had developed a quantum field theory for God and I must say it wasn&rsquo;t lacking in some indefinable kind of genius: there was a ubiquitous, invisible &ldquo;love field&rdquo; that filled the universe and had its own quanta, called something like a love-on. It made me smile. Others have got in touch too, mostly to berate me for not fearing The End of the World (or worse) at the hands of physicists and their wonderful machines. So it goes.</p> <p>The UK and US versions of my book differ in more than just the subtitle. The US version has no first person sections, and some people may prefer that, though they will never read of my car ride with Steven Weinberg and other encounters. That said, there is little of substance that is lost. The US publisher had more time to edit my manuscript, with obvious and positive consequences. And of course, my references to all kinds of things that would leave an American scratching their head have been removed, translated or explained. I hope it works.<br /> &nbsp;</p> http://www.iansample.com:/site/?q=content/god-physics-and-book-titles#comments CERN Fermilab God Higgs boson Large Hadron Collider Leon Lederman Peter Higgs the God particle Sun, 31 Oct 2010 21:51:21 +0000 Ian Sample 29 at http://www.iansample.com:/site What's next for the Higgs hunters? http://www.iansample.com:/site/?q=content/whats-next-higgs-hunters <p>And so it goes on. The International Conference on High Energy Physics (<a href="http://www.ichep2010.fr/">ICHEP</a>) in Paris came and went, but&nbsp; the Higgs boson is still at large. As expected, rumours that the world&#39;s most elusive particle had shown up at the Tevatron collider at Fermilab near Chicago failed to materialise into anything more concrete. Nonetheless, there was good news.</p> <p>As I mentioned in my previous post, the most likely Higgs results to come out of ICHEP should at least tell us more about where the Higgs particle <em>isn&#39;t</em>. That turned out to be the case. By combining data from countless collisions recorded by both Tevatron detectors, namely CDF and DZero, Fermilab physicists can now rule out a quarter of the masses that the Higgs particle might possibly have, in the Standard Model at least. It is slow and painstaking work this Higgs hunting business.</p> <p>I <a href="http://www.guardian.co.uk/science/2010/jul/26/higgs-boson-eludes-capture">wrote about the range of masses that the Tevatron has now excluded</a> for <a href="http://www.guardian.co.uk/science">the Guardian</a>, but to repeat them here: the collider can now say with some confidence that the Higgs boson does not lurk in the 158 to 175GeV mass range. We know from CERN&rsquo;s previous machine, the Large Electron Positron collider (again, with reasonable but not absolute confidence) that the Higgs is heavier than 114.4GeV. What does it all mean? In short, the beast is running out of places to hide.</p> <p>The Tevatron is due to close down at the end of next year, but lab staff are understandably keen to see it continue operating. The reasons go way beyond the Higgs hunt. Does the US have any another flagship high energy physics laboratory that is exploring the frontier of physics, as <a href="http://history.fnal.gov/wilson.html">Robert Wilson, the first director of the lab envisioned</a>? Large physics facilities like Fermilab are an inspiration for the next generation.</p> <p>What&rsquo;s under consideration in the US is a plan to keep the Tevatron running until 2014. If the machine runs for that long, some physicists at the lab believe they are in with a very good chance of bagging the Higgs particle.</p> <p>But what of <a href="http://public.web.cern.ch/public/en/lhc/lhc-en.html">CERN&rsquo;s shiny new Large Hadron Collider</a>? Won&rsquo;t it win the race to find the Higgs? I&rsquo;ve heard as many views as physicists I&rsquo;ve talked to. Some think it&rsquo;s highly unlikely the LHC will discover the Higgs (if it is there to be discovered) before the machine starts running at high energy after its 15 month shut down at the end of 2011. Others think the machine might well see <em>something</em> before that. Why the confidence? They seem to understand their detectors &ndash; primarily <a href="http://public.web.cern.ch/public/en/lhc/CMS-en.html">CMS</a> and <a href="http://public.web.cern.ch/public/en/lhc/CMS-en.html">Atlas</a> &ndash; so well, that they might be able to move on from measuring well known particles to looking seriously for new ones, earlier than expected. When the machine <a href="http://public.web.cern.ch/press/pressreleases/Releases2008/PR10.08E.html">was idled by an &quot;incident&quot; in 2008</a>, the physicists used incoming cosmic rays to test out their detectors. They got to know how they behaved with particles zipping through them before the real collisions started coming in.</p> <p>Earlier today, Fermilab <a href="http://www.symmetrymagazine.org/breaking/2010/08/05/higgs-hunting-what%E2%80%99s-next/">ran an article on the hunt for the Higgs</a>, asking &ldquo;What&rsquo;s next?&rdquo; It ends on an optimistic note:<br /> &quot;If the Higgs exists, the Tevatron is close to discovering or excluding it. The next year or two will be very interesting.&quot;<br /> There&#39;s no doubt about that. And with luck, the Tevatron will keep running for even longer.</p> http://www.iansample.com:/site/?q=content/whats-next-higgs-hunters#comments CERN Fermilab Higgs boson Large Hadron Collider Tevatron Thu, 05 Aug 2010 20:46:37 +0000 Ian Sample 22 at http://www.iansample.com:/site Waiting for the Godot particle http://www.iansample.com:/site/?q=content/waiting-godot-particle <p>To get to <a href="http://www.fnal.gov/">Fermilab</a> from downtown Chicago, you find <a href="http://www.chicagotraveler.com/maps/chicago-beaches-map.htm">Lake Michigan</a> and drive in the opposite direction. After about an hour on the freeway, the city shrinks to nothing in the rear-view mirror and you pick up an access road that turns into the 7,000 acre campus where the laboratory is based.</p> <p>The road cuts through a landscape of forests and lakes before arriving at one of my favourite sculptures. At first glance, it could be <a href="http://www.cretewest.com/PIX/talos.jpg">Talos straddling the road in case the Argonauts pay a visit</a>, but this 21-ton metal monster was designed and built by Robert Wilson, a former cowboy and first director of the laboratory. From almost any angle, the sculpture looks ungainly and off-kilter <a href="http://www.fnal.gov/pub/presspass/vismedia/gallery/buildings.html">(scroll down here)</a>, but lie on the road beneath it and look up. The sculpture&rsquo;s strained lines are hidden and a perfectly symmetrical form appears. It was meant to be that way. Wilson called the sculpture &ldquo;Broken Symmetry&rdquo;.</p> <p>The concept of symmetry breaking is fundamental in physics and central to the Higgs mechanism. The Higgs field breaks the symmetry between the electromagnetic force and the so-called weak force, the latter of which goes to work in certain radioactive processes and plays a vital role in keeping the sun shining. The field does this by giving mass to the weak force carrier particles, the W and Z bosons, while leaving the photon, which carries the electromagnetic force, massless and free to hurtle about at the speed of light. But that&rsquo;s another story.</p> <p>Fermilab is home to the Tevatron particle collider, an impressive old workhorse that lists among its successes the discovery of the top quark in 1995. The top quark is the heaviest known fundamental particle and weighs as much as a tungsten atom. If that doesn&rsquo;t sound much, bear in mind that a tungsten atom contains 74 protons, 110 neutrons and 74 electrons. It&rsquo;s the heaviest element used by living organisms.</p> <p>The Tevatron has been in the news again in recent weeks. <a href="http://www.science20.com/quantum_diaries_survivor/rumors_about_light_higgs">A vague rumour</a> emerged on a physicist&rsquo;s blog that the Tevatron had found the Higgs boson. Some media outlets got a bit tangled up over the story, reporting one day that <a href="http://www.telegraph.co.uk/science/large-hadron-collider/7885997/Large-Hadron-Collider-rival-Tevatron-has-found-Higgs-boson-say-rumours.html">the particle has been found</a>, and the next <a href="http://www.telegraph.co.uk/science/large-hadron-collider/7888012/Higgs-boson-discovery-rumours-false-say-Tevatron-scientists.html">that it hadn&#39;t</a>. At the time, <a href="http://twitter.com/iansample/status/18368225595">I bet Martin Rees&rsquo;s dog</a> that the Tevatron has not discovered the Higgs boson. That might seem an odd (not to say unethical) thing to bet, but <a href="http://iopscience.iop.org/0264-9381/25/22/229001">it&rsquo;s not the first time</a> the poor creature&rsquo;s life has been wagered.</p> <p>There are two detector teams at the Tevatron, CDF and Dzero, and the teams are due to announce the combined results from their Higgs searches at 4pm Central European Time on Monday&nbsp; 26th July from the <a href="http://www.ichep2010.fr/">ICHEP conference in Paris</a>. I&rsquo;ll post the results here at the same time, but for now, some background to explain why I don&rsquo;t think the Higgs has been found and why Lord Rees&#39;s dog is safe.</p> <p>In January, the Tevatron teams <a href="http://arxiv.org/abs/1001.4162">published their last combined search for the Higgs particle</a>. The paper is pretty technical, but essentially it looks to see whether there is evidence for so-called Standard Model Higgs particles decaying into W bosons, however they are made in the first place in the machine. The searches rule out any Higgs boson (with 95% confidence) between a mass of 162 GeV and 166 GeV. A previous accelerator at Cern, the Large Electron Positron (LEP) collider, ruled out the possibility of the Higgs particle weighing less than 114.4 GeV. &nbsp;</p> <p>With six months or so more collisions under their belts, we might expect the Tevatron teams to have ruled out the existence of a Higgs particle over an even greater range of masses. That would be good news. It would narrow down the region where the Higgs must be hiding. We can&#39;t really expect them to have found the elusive beast. As I joked (very lamely) a week or so ago, physicists have waited so long to see the Higgs boson, or &quot;God particle&quot;, in their experiments, they might want to rename it <a href="http://twitter.com/iansample/status/18983671870">the Godot particle</a>.</p> <p>&nbsp;<br /> What is clear is that the Tevatron and its detector teams are working well and making solid progress in the hunt for the Higgs particle. Officially, the machine is due to close at the end of 2011, but a proposal to run for a few years longer is under consideration. With the <a href="http://lhc.web.cern.ch/lhc/">Large Hadron Collider at Cern</a> having little chance of finding the Higgs boson before it begins high energy runs at the end of 2012, there is surely a strong argument to keep the Tevatron in the race.<br /> &nbsp;</p> http://www.iansample.com:/site/?q=content/waiting-godot-particle#comments CERN God particle Higgs boson Large Hadron Collider LHC Tevatron Sun, 25 Jul 2010 22:43:50 +0000 Ian Sample 21 at http://www.iansample.com:/site