Interesante columna de un Físico de partículas de la UCL (Inglaterra) sobre cómo "se hace Ciencia". Sale en el Guardian de ayer<div><div><br><div><div><br></div><div><div style><div style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;float:left">
<a href="http://www.guardian.co.uk/science/life-and-physics/2012/feb/25/1" target="_blank" style="color:rgb(17,85,204)">http://www.guardian.co.uk/science/life-and-physics/2012/feb/25/1</a><h1 style="color:rgb(51,51,51);padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:2px;margin-left:0px;border-collapse:collapse;border-top-color:initial;border-right-color:rgb(214,29,0);border-bottom-color:rgb(214,29,0);border-left-color:rgb(214,29,0);font-family:georgia,serif;font-weight:normal;font-size:2.166em;line-height:1.154;width:460px;border-top-width:0px;border-top-style:initial">
<br></h1><h1 style="color:rgb(51,51,51);padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:2px;margin-left:0px;border-collapse:collapse;border-top-color:initial;border-right-color:rgb(214,29,0);border-bottom-color:rgb(214,29,0);border-left-color:rgb(214,29,0);font-family:georgia,serif;font-weight:normal;font-size:2.166em;line-height:1.154;width:460px;border-top-width:0px;border-top-style:initial">
Gaming the system? Neutrinos, theorists and citations</h1><p style="padding-top:0px;padding-right:0px;padding-bottom:34px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;color:rgb(102,102,102);font-size:1.333em;line-height:1.25;width:460px">
If you hold back results because they contradict your favourite theory, or even because they contradict other experiments, you might as well not make a measurement in the first place.</p></div><ul style="color:rgb(51,51,51);line-height:15px;font-size:12px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:5px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;list-style-type:none;list-style-position:initial;float:right;width:140px">
<li style="margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;border-collapse:collapse;list-style-type:none;list-style-position:initial;background-repeat:no-repeat no-repeat">
<ul style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;list-style-type:none;background-repeat:no-repeat no-repeat">
<li style="margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;border-collapse:collapse;border-top-style:none!important;clear:left;float:none;border-right-style:none!important;border-bottom-style:none!important;border-left-style:none!important;border-width:initial!important;border-color:initial!important;border-width:initial!important;border-color:initial!important;background-repeat:no-repeat no-repeat">
</li><li style="margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:5px;margin-right:8px;margin-bottom:0px;border-collapse:collapse;float:none;clear:left;border-top-style:none!important;border-right-style:none!important;border-bottom-style:none!important;border-left-style:none!important;border-width:initial!important;border-color:initial!important;border-width:initial!important;border-color:initial!important;background-repeat:no-repeat no-repeat">
<span style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;line-height:1.2;font-size:0.88em;display:block;background-repeat:no-repeat no-repeat"><a href="http://www.facebook.com/dialog/feed?app_id=180444840287&link=http://www.guardian.co.uk/science/life-and-physics/2012/feb/25/1&display=popup&redirect_uri=http://static-serve.appspot.com/static/facebook-share/callback.html&show_error=false" target="_blank" style="color:rgb(59,77,123);padding-top:2px!important;padding-right:4px!important;padding-bottom:2px;padding-left:4px!important;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;text-decoration:none;background-color:rgb(237,238,244);border-top-width:1px;border-right-width:1px;border-bottom-width:1px;border-left-width:1px;border-top-style:solid;border-right-style:solid;border-bottom-style:solid;border-left-style:solid;border-top-color:rgb(205,213,229);border-right-color:rgb(205,213,229);border-bottom-color:rgb(205,213,229);border-left-color:rgb(205,213,229);border-top-left-radius:3px;border-top-right-radius:3px;border-bottom-right-radius:3px;border-bottom-left-radius:3px;min-height:16px;float:left;display:inline-block;background-repeat:no-repeat no-repeat"><span style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:2px;margin-bottom:1px;margin-left:1px;border-collapse:collapse;background-image:url('http://static.guim.co.uk/static/5e8a33fc00d9d9e6d2e5ca71dd905bae18283811/common/styles/images/btn_facebook_12x12.png');width:13px;min-height:13px;float:left;background-repeat:no-repeat no-repeat"></span><span style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;line-height:1.3;color:rgb(59,89,152);background-repeat:no-repeat no-repeat">Share</span><span style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;background-color:rgb(255,255,255);width:1px;min-height:1px;display:block;background-repeat:no-repeat no-repeat"></span><span style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;background-color:rgb(255,255,255);width:1px;min-height:1px;display:block;background-repeat:no-repeat no-repeat"></span><span style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;background-color:rgb(255,255,255);width:1px;min-height:1px;display:block;background-repeat:no-repeat no-repeat"></span><span style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;background-color:rgb(255,255,255);width:1px;min-height:1px;display:block;background-repeat:no-repeat no-repeat"></span></a><span style="padding-top:1px;padding-right:2px;padding-bottom:1px;padding-left:2px;margin-top:1px;margin-right:0px;margin-bottom:0px;margin-left:6px;border-collapse:collapse;border-top-width:1px;border-right-width:1px;border-bottom-width:1px;border-left-width:1px;border-top-style:solid;border-right-style:solid;border-bottom-style:solid;border-left-style:solid;border-top-color:rgb(205,213,229);border-right-color:rgb(205,213,229);border-bottom-color:rgb(205,213,229);border-left-color:rgb(205,213,229);min-height:14px;float:left;background-repeat:no-repeat no-repeat"><i style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;border-top-style:solid;border-right-style:solid;border-bottom-style:solid;border-left-style:solid;border-top-color:transparent;border-bottom-color:transparent;border-left-color:transparent;border-width:initial;border-right-color:white;display:block;min-height:1px;border-width:initial;border-top-width:4px;border-right-width:5px;border-bottom-width:4px;border-left-width:0px;background-repeat:no-repeat no-repeat"></i><u style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;border-top-style:solid;border-right-style:solid;border-bottom-style:solid;border-left-style:solid;border-top-color:transparent;border-bottom-color:transparent;border-left-color:transparent;border-width:initial;border-right-color:rgb(215,215,215);display:block;min-height:1px;border-width:initial;border-top-width:4px;border-right-width:5px;border-bottom-width:4px;border-left-width:0px;background-repeat:no-repeat no-repeat"></u>4</span></span></li>
<li style="margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:5px;margin-right:5px;margin-bottom:5px;border-collapse:collapse;float:left;background-repeat:no-repeat no-repeat">
<span style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat"><a href="http://www.reddit.com/submit?url=http%3A%2F%2Fwww.guardian.co.uk%2Fscience%2Flife-and-physics%2F2012%2Ffeb%2F25%2F1&title=" target="_blank" style="color:rgb(0,86,137);padding-top:0px;padding-right:0px;padding-bottom:2px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;text-decoration:none;display:inline-block;min-height:16px;background-repeat:no-repeat no-repeat"><img src="http://static.guim.co.uk/static/5e8a33fc00d9d9e6d2e5ca71dd905bae18283811/common/images/icon_reddit.gif" style="padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-top: 0px; margin-right: 3px; margin-bottom: 0px; margin-left: 0px; border-collapse: collapse; border-top-style: none; border-right-style: none; border-bottom-style: none; border-left-style: none; border-width: initial; border-color: initial; min-height: 2.3ex; vertical-align: top; background-repeat: no-repeat no-repeat; "></a> <a href="http://www.reddit.com/submit?url=http%3A%2F%2Fwww.guardian.co.uk%2Fscience%2Flife-and-physics%2F2012%2Ffeb%2F25%2F1&title=" target="_blank" style="color:rgb(0,86,137);padding-top:0px;padding-right:0px;padding-bottom:2px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;text-decoration:none;display:inline-block;min-height:16px;background-repeat:no-repeat no-repeat">reddit this</a></span></li>
</ul></li><li style="margin-left:0px;padding-top:3px;padding-right:0px;padding-bottom:6px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;border-collapse:collapse;border-top-color:rgb(153,153,153);border-top-style:dotted;border-top-width:1px;background-repeat:no-repeat no-repeat">
<a href="http://www.guardian.co.uk/science/life-and-physics/2012/feb/25/1#start-of-comments" target="_blank" style="color:rgb(0,86,137);padding-top:0px;padding-right:0px;padding-bottom:2px;padding-left:20px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;text-decoration:none;background-image:url('http://resource.guim.co.uk/discussion/static/1780/images/comment-icon16x16.gif');min-height:15px;display:block;clear:both;background-repeat:no-repeat no-repeat">Comments (<span style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat">9</span>)</a></li>
</ul></div><div style><div style="padding-top:5px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;border-top-color:rgb(214,29,0);border-right-color:rgb(214,29,0);border-bottom-color:rgb(214,29,0);border-left-color:rgb(214,29,0);border-top-width:1px;border-top-style:solid;background-repeat:no-repeat no-repeat">
<div style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat"><p style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:13px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat">
So it looks like neutrinos respect the speed limit after all. At least, the OPERA experimentalists <a href="http://www.guardian.co.uk/science/2012/feb/23/faster-light-neutrinos-faulty-connection" target="_blank" style="color:rgb(0,86,137);padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;text-decoration:none;background-repeat:no-repeat no-repeat">announced a couple of days ago</a> that they have found one problem (with a connector in their experiment) which could have led to a faulty timing measurement. When they run again with this fixed, they may well get a result compatible with the speed of light.</p>
<p style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:13px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat">You'll note the words "could" and "may well" in there. We don't know yet. But the faster-than-light result already had a hard time gaining credibility in the face of all the evidence in favour of relativity. The <a href="http://www.guardian.co.uk/commentisfree/2011/dec/12/higgs-boson-particle-physics-benefit" target="_blank" style="color:rgb(0,86,137);padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;text-decoration:none;background-repeat:no-repeat no-repeat">balance of probability</a> just shifted further in favour of Einstein, and <a href="http://www.guardian.co.uk/science/2011/sep/23/physicists-speed-light-violated" target="_blank" style="color:rgb(0,86,137);padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;text-decoration:none;background-repeat:no-repeat no-repeat">Jim Al-Khalili's shorts</a>, on this one.</p>
<p style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:13px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat"></p><p style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:13px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat">
The connector problem will be a depressingly mundane explanation for an intriguing anomaly, if it turns out that way. I still respect OPERA for putting out a result though. Once you've decided to measure something, you should publish the result, even if it is not the one you expected or hoped for. (This is even more important for example for trials of a new medicine than for neutrinos.) Of course the OPERA physicists suspected their own result was wrong, they were <a href="http://press.web.cern.ch/press/PressReleases/Releases2011/PR19.11E.html" target="_blank" style="color:rgb(0,86,137);padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;text-decoration:none;background-repeat:no-repeat no-repeat">pretty clear about this from the start</a>, emphasising the need for checks. But the main reason for that suspicion was not to do with the experiment itself, but to do with the weight of independent evidence in favour of relativity.</p>
<p style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:13px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat">Here's the problem. If you hold back results because they contradict your favourite theory, or even because they contradict other experiments, you might as well not make a measurement in the first place, since you are so heavily biasing yourself.</p>
<p style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:13px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat">So you have to publish, and repeat the experiment, and check and recheck again. And sometimes you find a dodgy connector. Damn.</p>
<p style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:13px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat">There are compensations, of course. Several people have pointed out that the OPERA paper has <a href="http://inspirehep.net/record/928153?ln=en" target="_blank" style="color:rgb(0,86,137);padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;text-decoration:none;background-repeat:no-repeat no-repeat">picked up a lot of citations</a>. If you live in one of the dumber citation-metric-based wonderlands (which, for example, some University league tables do) then this will look good, even if the vast majority of the citations are disagreeing with you. High impact.</p>
<p style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:13px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat">I don't think they were gaming the system. I doubt there is a single physicist on OPERA who doesn't wish that this connector problem had been found <em style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat">before</em> they published, even if that would mean they measured the speed of light and got many fewer citations (and less media attention).</p>
<p style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:13px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat">On the same day these results came out, I went to Google London for breakfast at the launch of a film about CERN being made by <a href="http://www.filmsofrecord.com/" target="_blank" style="color:rgb(0,86,137);padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;text-decoration:none;background-repeat:no-repeat no-repeat">Films of Record</a>. While they make the film, snippets and side-lines will be <a href="http://www.youtube.com/user/CERNPeople" target="_blank" style="color:rgb(0,86,137);padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;text-decoration:none;background-repeat:no-repeat no-repeat">posted on youtube</a>, and there are a couple there already which are worth a watch. I especially like this one:</p>
<span style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;display:block;width:auto;background-repeat:no-repeat no-repeat"></span><p style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:13px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat">
and in particular Zach (at the ATLAS barbecue) at the end. He talks about about theorists inventing weird new physics scenarios that might show up at the Large Hadron Collider:</p><blockquote style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:45px;margin-top:0px;margin-right:40px;margin-bottom:10px;margin-left:0px;border-collapse:collapse;color:rgb(102,102,102);background-image:url('http://static.guim.co.uk/static/5e8a33fc00d9d9e6d2e5ca71dd905bae18283811/common/styles/images/quote_red.gif');background-repeat:no-repeat no-repeat">
<p style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:13px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat">You have these people trying to just predict, and predict as many different things as they can. Because if one of them is right, they'll be famous. And if all of them are wrong - they'll be like everybody else!</p>
</blockquote><p style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:13px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat">
<br style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat"><em style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat">Zach Marshall, ATLAS</em></p>
<p style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:13px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat">... and he's right. So there you have it. Experimentalists get ignored if they are right, and hugely cited if they are wrong. Theorists get ignored if they are wrong, but a Nobel Prize if they are right.</p>
<p style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:13px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat">Not quite true, but not completely wrong either.</p>
<p style="padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;margin-top:0px;margin-right:0px;margin-bottom:13px;margin-left:0px;border-collapse:collapse;background-repeat:no-repeat no-repeat">Anyway, back to OPERA and the neutrinos, let's not forget that the fat lady hasn't quite sung yet.</p>
</div></div></div><br><div class="gmail_quote">El 23 de febrero de 2012 08:22, Gaston Giribet <span dir="ltr"><<a href="mailto:gaston@df.uba.ar">gaston@df.uba.ar</a>></span> escribió:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Erratum sobre las referencias: Cuando dije la sección 3 de <a href="http://arxiv.org/abs/1109.5685" target="_blank">arXiv.1109.5685</a> me refería a la sección 3 de <a href="http://arxiv.org/abs/1109.4897" target="_blank">arXiv:1109.4897</a>.<div class="HOEnZb">
<div class="h5"><div><br><div class="gmail_quote">
On Thu, Feb 23, 2012 at 11:14 AM, Gaston Giribet <span dir="ltr"><<a href="mailto:gaston@df.uba.ar" target="_blank">gaston@df.uba.ar</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>Hola, </div><div><br></div><div>Yo no creo que esto de OPERA sorprenda a demasiada gente. Era la actitud más homologada la de ser escéptico al respecto; todo el mundo suponía que algún error sistemático debía haber. Después de todo, había tanto observaciones experimentales que decían que los neutrinos eran sublumínicos (la supernova <a href="http://es.wikipedia.org/wiki/SN_1987A" target="_blank">SN 1987a</a> es el ejemplo por antonomasia) cuanto también argumentos teóricos que decían que si los neutrinos fueran superlumínicos muchos otros efectos extraños habríamos observado ya (mencioné yo el paper de <a href="http://arxiv.org/abs/1109.6562" target="_blank">Glashow et al. 2011</a> en un mail anterior.)</div>
<div><br></div><div>Acerca de lo que dice Daniel, de que, de ser ese el error, sería el mismo mucho más "mundano" que las explicaciones que algunos dieron para el mismo, acuerdo totalmente. Hubo todo tipo de especulaciones de lo más aventuradas, algunas de éstas propuestas por fenomenólogos muy serios; notables son los casos de <a href="http://arxiv.org/abs/1109.4897" target="_blank">S. Gubser 2011</a> y <a href="http://arxiv.org/abs/1109.5687" target="_blank">G. Dvali et al. 2011</a>. Lo cierto es que ni los autores de muchos de esos papers debían creerse el resultado del experimento. </div>
<div><br></div><div>Yo creo que, de comprobarse que el error ha sido ése, se trató de una gran falta de seriedad: Soldás mal un cable y concluís que la teoría de la relatividad está mal- diría uno parodiando la situación (o no tanto). De ser un error sistemático de tal tenor -y muy probablemente lo haya sido- y siendo que las conclusiones que se pretendían derivar del resultado (aunque tímidamente presentadas y con pretendida cautela) llevaban en germen la afirmación de que la teoría de la relatividad podía estar mal, todo este asunto se convertiría en un verdadero papelón; un papelón que derivó en un montón de ruido y poco más (ese "poco más" se traduce en centenares de noticias -no todas responsablemente escritas- y 214 citas en pocos meses a un paper que como resultado sólo produjo risa, sorpresa, indignación, dependiendo de a quién se le pregunte.)</div>
<div><br></div><div>Pero volviendo a lo que decía Daniel sobre las explicaciones no tan mundanas que fueron apareciendo, vale decir que hubo, también, explicaciones más ortodoxas: El más común de los intentos por explicar de dónde podía venir el error era la medición del tiempo de vuelo. Pueden ver en la sección 3 del paper original <a href="http://arxiv.org/abs/1109.5685" target="_blank">arXiv:1109.5685</a> que se explica el método estadístico con el que se midió el tiempo de vuelo de los neutrinos que abandonan el detector de muones del CERN y arriban al Gran Sasso luego de algo así como 732 kilómetros. Básicamente, se toma una gran cantidad de datos a partir de la distribución estadística de cuándo salen los neutrinos y luego se coteja con la distribución estadística del arribo de los mismos. El gráfico tiene una forma de meseta aplanada, y la parte significativa del análisis viene de la rampa de subida y de bajada de esa meseta, por lo cual se reduce significativamente respecto a la cantidad de datos inicial. Si leen el artículo verán que uno ya nota que "se cubren de más" cuando comienzan a discutir la parte de la medición del tiempo de vuelo. No obstante, unos meses después (no estoy seguro de los detalles de esto último porque ya no seguí el tema con interés) la colaboración afirmó haber mejorado substancialmente la forma en la que se medía el tiempo de vuelo, lo que desconcertó a muchos ya que, como decía, era ése precisamente el blanco principal de las críticas. De todos modos, como se puede ver en el anuncio oficial, sigue siendo el tiempo de vuelo uno de los dos posibles errores (aunque es un aspecto diferente de la medición de esa cantidad.) La segunda posibilidad es, ya, bochornosa, ... y no porque uno no pueda conectar mal los cables, pero, en todo caso, fijate mejor si le vas a apuntar a Einstein, loco!</div>
<div><br></div><div>Ahora parece ser que podría ser una cosa tanto más ... no sé. En fin, ... seguimos con que E=mc^2/\sqrt{1-v^2/c^2} y esto es real, por suerte :)</div>
<div><br></div><div>G,</div><div><br></div><div><br></div><div><div><div><br><br><div class="gmail_quote">On Thu, Feb 23, 2012 at 9:05 AM, Daniel de Florian <span dir="ltr"><<a href="mailto:deflo@df.uba.ar" target="_blank">deflo@df.uba.ar</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hola,<div><br></div><div>aca va el anuncio oficial, en Mayo debería confirmarse si ese es el origen del efecto, ciertamente un poco mas mundano que la mayoría de las especulaciones que se presentaron para explicarlo en los últimos meses :)</div>
<div><br></div><div>Saludos,</div><div>Daniel</div><div><br></div><div><span style="font-family:Helvetica;font-size:medium">Dear Colleagues,</span><span style="font-family:Helvetica;font-size:medium"><br>
</span><span style="font-family:Helvetica;font-size:medium"><br></span><span style="font-family:Helvetica;font-size:medium"><br></span><span style="font-family:Helvetica;font-size:medium">The OPERA collaboration has informed its funding agencies and host</span><span style="font-family:Helvetica;font-size:medium"><br>
</span><span style="font-family:Helvetica;font-size:medium">laboratories that it has identified two possible effects that could have an</span><span style="font-family:Helvetica;font-size:medium"><br>
</span><span style="font-family:Helvetica;font-size:medium">influence on its neutrino timing measurement. These both require further</span><span style="font-family:Helvetica;font-size:medium"><br>
</span><span style="font-family:Helvetica;font-size:medium">tests with a short pulsed beam. If confirmed, one would increase the size of</span><span style="font-family:Helvetica;font-size:medium"><br>
</span><span style="font-family:Helvetica;font-size:medium">the measured effect, the other would diminish it. The first possible effect</span><span style="font-family:Helvetica;font-size:medium"><br>
</span><span style="font-family:Helvetica;font-size:medium">concerns an oscillator used to provide the time stamps for GPS</span><span style="font-family:Helvetica;font-size:medium"><br>
</span><span style="font-family:Helvetica;font-size:medium">synchronizations. It could have led to an overestimate of the neutrino's</span><span style="font-family:Helvetica;font-size:medium"><br>
</span><span style="font-family:Helvetica;font-size:medium">time of flight. The second concerns the optical fibre connector that brings</span><span style="font-family:Helvetica;font-size:medium"><br>
</span><span style="font-family:Helvetica;font-size:medium">the external GPS signal to the OPERA master clock, which may not have been</span><span style="font-family:Helvetica;font-size:medium"><br>
</span><span style="font-family:Helvetica;font-size:medium">functioning correctly when the measurements were taken. If this is the case,</span><span style="font-family:Helvetica;font-size:medium"><br>
</span><span style="font-family:Helvetica;font-size:medium">it could have led to an underestimate of the time of flight of the</span><span style="font-family:Helvetica;font-size:medium"><br>
</span><span style="font-family:Helvetica;font-size:medium">neutrinos. The potential extent of these two effects is being studied by the</span><span style="font-family:Helvetica;font-size:medium"><br>
</span><span style="font-family:Helvetica;font-size:medium">OPERA collaboration. New measurements with short pulsed beams are scheduled</span><span style="font-family:Helvetica;font-size:medium"><br>
</span><span style="font-family:Helvetica;font-size:medium">for May.</span><span style="font-family:Helvetica;font-size:medium"><br></span><span style="font-family:Helvetica;font-size:medium"><br>
</span><span style="font-family:Helvetica;font-size:medium"><br></span><span style="font-family:Helvetica;font-size:medium">Best regards,</span><span style="font-family:Helvetica;font-size:medium"><br>
</span><span style="font-family:Helvetica;font-size:medium"><br></span><span style="font-family:Helvetica;font-size:medium">Rolf Heuer</span><span style="font-family:Helvetica;font-size:medium"><br>
</span><br><div class="gmail_quote">El 22 de febrero de 2012 19:05, <span dir="ltr"><<a href="mailto:paz@df.uba.ar" target="_blank">paz@df.uba.ar</a>></span> escribió:<div><div><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Estimados,<br>
<br>
Hace unos meses se reporto que el experimento Opera habia detectado que los neutrinos viajaban a velocidad mayor que la de la luz. El tiempo de llegada de los neutrinos desde su emision en el Cern hasta el detector de Opera era 60 nseg mas que lo admitido por la teoria de la relatividad. Mucha tinta corrio desde ese entonces. Ahora, al al parecer hay fuertes indicios sobre la existencia de un error sistematico en el experimento... Pueden leer la noticia en el portal de la revista Science (el link esta abajo). Segun se informa hoy, los famosos 60 nanosegundos se explican por una falla en la conexion de un cable de fibra optica que iba desde el receptor del GPS a una plaqueta de adquisicion en una computadora... Si esto es cierto es como para reir. A veces asi avanza la ciencia! Si alguien sabe algo mas sobre esto avisen.. Saludos,<br>
<br>
Juan Pablo<br>
<br>
<a href="http://news.sciencemag.org/scienceinsider/2012/02/breaking-news-error-undoes-faster.html?rss=1&utm_source=twitterfeed&utm_medium=twitter#.T0VAu8O-G8w.twitter" target="_blank">http://news.sciencemag.org/<u></u>scienceinsider/2012/02/<u></u>breaking-news-error-undoes-<u></u>faster.html?rss=1&utm_source=<u></u>twitterfeed&utm_medium=<u></u>twitter#.T0VAu8O-G8w.twitter</a><br>
<br>
<br>
<br>
<br>
Dr Juan Pablo Paz<br>
Profesor Titular UBA, Investigador Principal CONICET<br>
Departamento de Fisica & Instituto de Fisica de Buenos Aires<br>
FCEyN UBA, Pabellon 1, Ciudad Universitaria<br>
1428 Buenos Aires, Argentina<br>
Email: <a href="mailto:paz@df.uba.ar" target="_blank">paz@df.uba.ar</a><br>
Phone: +54-11-45763353<br>
<a href="http://www.df.uba.ar/users/paz" target="_blank">http://www.df.uba.ar/users/paz</a><br>
<a href="http://www.qufiba.df.uba.ar" target="_blank">http://www.qufiba.df.uba.ar</a><br>
<br>
</blockquote></div></div></div><span><font color="#888888"><br><br clear="all"><div><br></div>-- <br>Daniel de Florian<br>
</font></span></div>
</blockquote></div><br><br clear="all"><div><br></div></div></div><span><font color="#888888">-- <br>Gaston Giribet<br>Physics Department<br>University of Buenos Aires<br>
</font></span></div>
</blockquote></div><br><br clear="all"><div><br></div>-- <br>Gaston Giribet<br>Physics Department<br>University of Buenos Aires<br>
</div>
</div></div></blockquote></div><br><br clear="all"><div><br></div>-- <br>Val<br>
</div></div></div></div>