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	<title>Comments on: The LHC Olympics and the Mysteries of Mass</title>
	<atom:link href="http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/feed/" rel="self" type="application/rss+xml" />
	<link>http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/</link>
	<description>Random samplings from a universe of ideas.</description>
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		<title>By: Particle physics marches on &#124; Cosmic Variance</title>
		<link>http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/comment-page-1/#comment-67</link>
		<dc:creator>Particle physics marches on &#124; Cosmic Variance</dc:creator>
		<pubDate>Fri, 31 Mar 2006 18:34:31 +0000</pubDate>
		<guid isPermaLink="false">http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/#comment-67</guid>
		<description>[...] Physicists (like us) are, with good reason, eagerly anticipating results from the Large Hadron Collider at CERN, scheduled to turn on next year. The LHC will collide protons at much higher energies than ever before, giving us direct access to a regime that has been hidden from us up to now. But until then, a whole host of smaller experiments are interrogating particle physics from a variety of different angles, using clever techniques to get indirect information about new physics. Just a quick rundown of some recent results: [...]</description>
		<content:encoded><![CDATA[<p>[...] Physicists (like us) are, with good reason, eagerly anticipating results from the Large Hadron Collider at CERN, scheduled to turn on next year. The LHC will collide protons at much higher energies than ever before, giving us direct access to a regime that has been hidden from us up to now. But until then, a whole host of smaller experiments are interrogating particle physics from a variety of different angles, using clever techniques to get indirect information about new physics. Just a quick rundown of some recent results: [...]</p>
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		<title>By: Cosmic Variance</title>
		<link>http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/comment-page-1/#comment-66</link>
		<dc:creator>Cosmic Variance</dc:creator>
		<pubDate>Wed, 04 Jan 2006 06:07:29 +0000</pubDate>
		<guid isPermaLink="false">http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/#comment-66</guid>
		<description>&lt;strong&gt;The BBC on the LHC&lt;/strong&gt;

	The BBC has a nice article about CERN&#8217;s Large Hadron Collider (LHC).
	I&#8217;ve mentioned the LHC before, and what we expect will be its central role in providing insights into some of the biggest questions in particle physics and cosmology. Th...</description>
		<content:encoded><![CDATA[<p><strong>The BBC on the LHC</strong></p>
<p>	The BBC has a nice article about CERN&#8217;s Large Hadron Collider (LHC).<br />
	I&#8217;ve mentioned the LHC before, and what we expect will be its central role in providing insights into some of the biggest questions in particle physics and cosmology. Th&#8230;</p>
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		<title>By: Alejandro Rivero</title>
		<link>http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/comment-page-1/#comment-65</link>
		<dc:creator>Alejandro Rivero</dc:creator>
		<pubDate>Fri, 05 Aug 2005 18:20:48 +0000</pubDate>
		<guid isPermaLink="false">http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/#comment-65</guid>
		<description>I joint to the vote for a linear collider somewhere.

As for the background, isn&#039;t a theoretical calculation after all? I mean, perhaps the organisers of the Olympics expected it to be evaluated by the participants, from general collider parameters.


JD comment: &lt;i&gt; It&#039;s not the biases in the analysis that I worry about; data can always be reanalyzed with different assumptions. It&#039;s that something important might slip past the cuts that they need to make, and never get recorded. &lt;/i&gt;

...reminders me of another thing: is someone out thare taking care of permanent backup of LEPI+LEPII data, just in case non MSSM analysis is needed? Same about tevatron, I hope.</description>
		<content:encoded><![CDATA[<p>I joint to the vote for a linear collider somewhere.</p>
<p>As for the background, isn&#8217;t a theoretical calculation after all? I mean, perhaps the organisers of the Olympics expected it to be evaluated by the participants, from general collider parameters.</p>
<p>JD comment: <i> It&#8217;s not the biases in the analysis that I worry about; data can always be reanalyzed with different assumptions. It&#8217;s that something important might slip past the cuts that they need to make, and never get recorded. </i></p>
<p>&#8230;reminders me of another thing: is someone out thare taking care of permanent backup of LEPI+LEPII data, just in case non MSSM analysis is needed? Same about tevatron, I hope.</p>
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		<title>By: Mark</title>
		<link>http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/comment-page-1/#comment-64</link>
		<dc:creator>Mark</dc:creator>
		<pubDate>Fri, 05 Aug 2005 10:48:55 +0000</pubDate>
		<guid isPermaLink="false">http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/#comment-64</guid>
		<description>Killjoy! Oh sure, it&#039;s all fun and games until someone knows what they&#039;re talking about :)</description>
		<content:encoded><![CDATA[<p>Killjoy! Oh sure, it&#8217;s all fun and games until someone knows what they&#8217;re talking about <img src='http://blogs.discovermagazine.com/cosmicvariance/wp-includes/images/smilies/icon_smile.gif' alt=':)' class='wp-smiley' /> </p>
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		<title>By: JoAnne</title>
		<link>http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/comment-page-1/#comment-63</link>
		<dc:creator>JoAnne</dc:creator>
		<pubDate>Fri, 05 Aug 2005 06:21:34 +0000</pubDate>
		<guid isPermaLink="false">http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/#comment-63</guid>
		<description>Hi Folks,

Hate to squash your enthusiasm, but don&#039;t expect much from the LHC Olympics.  Why, you ask?  It is a good idea, but it&#039;s not being implemented in a realistic manner.  There are many flaws inherent in theorists pretending to do experimenter&#039;s tasks.  But there is a really, really BIG one associated with the LHC Olympics.  Namely, the folks in charge have not given the background associated with the signals they report.  (Presumably because it would take too much time and computer power.)  This means that one literally cannot do anything meaningful with the data.  For example, they give a signal which is obviously associated with neutralino production.  Unless one knows better, one would not realize that the signal rate they report is statistically insignificant.  In other words, it is swamped by background events.  It would never be reported and thus cannot be used in the determination of the underlying physics.  The physics reality of the LHC is much more complicated than what is being represented in the LHC Olympics.  I wouldn&#039;t expect any data-driven theorists to waste their time participating.</description>
		<content:encoded><![CDATA[<p>Hi Folks,</p>
<p>Hate to squash your enthusiasm, but don&#8217;t expect much from the LHC Olympics.  Why, you ask?  It is a good idea, but it&#8217;s not being implemented in a realistic manner.  There are many flaws inherent in theorists pretending to do experimenter&#8217;s tasks.  But there is a really, really BIG one associated with the LHC Olympics.  Namely, the folks in charge have not given the background associated with the signals they report.  (Presumably because it would take too much time and computer power.)  This means that one literally cannot do anything meaningful with the data.  For example, they give a signal which is obviously associated with neutralino production.  Unless one knows better, one would not realize that the signal rate they report is statistically insignificant.  In other words, it is swamped by background events.  It would never be reported and thus cannot be used in the determination of the underlying physics.  The physics reality of the LHC is much more complicated than what is being represented in the LHC Olympics.  I wouldn&#8217;t expect any data-driven theorists to waste their time participating.</p>
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		<title>By: Mark</title>
		<link>http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/comment-page-1/#comment-62</link>
		<dc:creator>Mark</dc:creator>
		<pubDate>Thu, 04 Aug 2005 21:26:22 +0000</pubDate>
		<guid isPermaLink="false">http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/#comment-62</guid>
		<description>Hadron colliders are great machines for discovering particles, and can certainly take you some way to nailing down a class of models. However, lepton machines, with their precision, are great machines for discovering specifically what the model is and how the new particles fit into our understanding of space and time (as in SUSY or extra dimensions).

Jacques last comment is important. It is one of the arguments (I think) that it is useful to have a future International Linear Collider and the LHC running concurrently for some period, so that one could go back and, in principle, go back and run in some parameter region.</description>
		<content:encoded><![CDATA[<p>Hadron colliders are great machines for discovering particles, and can certainly take you some way to nailing down a class of models. However, lepton machines, with their precision, are great machines for discovering specifically what the model is and how the new particles fit into our understanding of space and time (as in SUSY or extra dimensions).</p>
<p>Jacques last comment is important. It is one of the arguments (I think) that it is useful to have a future International Linear Collider and the LHC running concurrently for some period, so that one could go back and, in principle, go back and run in some parameter region.</p>
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		<title>By: Jacques Distler</title>
		<link>http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/comment-page-1/#comment-61</link>
		<dc:creator>Jacques Distler</dc:creator>
		<pubDate>Thu, 04 Aug 2005 21:20:55 +0000</pubDate>
		<guid isPermaLink="false">http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/#comment-61</guid>
		<description>&lt;blockquote&gt;It won&#039;t be easy to identify (once LHC is running) what kind of
supersymmetric standard model it is, if at all. There is a many-to-one
map, ie, one and the same set of given experimental data tends to
match many quite different discrete choices of parameters of the
supersymmetric standard model.&lt;/blockquote&gt;

My understanding is that&#039;s largely because there are so few independent &quot;signals&quot; that they can measure at the LHC. And we&#039;re mapping a very high-dimensional parameter space into this low-dimensional signal space.

(This is also rather discontinuous map, as various channels open up, or shut off, as you twiddle the parameters of the theory.)

&lt;blockquote&gt;On top of that, each of the
groups seem to have their own class of pet models they focus on. I
wonder how one could possibly find something unexpected in this
manner.&lt;/blockquote&gt;

It&#039;s not the biases in the analysis that I worry about; data can always be reanalyzed with different assumptions. It&#039;s that something important might slip past the cuts that they need to make, and never get recorded.</description>
		<content:encoded><![CDATA[<blockquote><p>It won&#8217;t be easy to identify (once LHC is running) what kind of<br />
supersymmetric standard model it is, if at all. There is a many-to-one<br />
map, ie, one and the same set of given experimental data tends to<br />
match many quite different discrete choices of parameters of the<br />
supersymmetric standard model.</p></blockquote>
<p>My understanding is that&#8217;s largely because there are so few independent &#8220;signals&#8221; that they can measure at the LHC. And we&#8217;re mapping a very high-dimensional parameter space into this low-dimensional signal space.</p>
<p>(This is also rather discontinuous map, as various channels open up, or shut off, as you twiddle the parameters of the theory.)</p>
<blockquote><p>On top of that, each of the<br />
groups seem to have their own class of pet models they focus on. I<br />
wonder how one could possibly find something unexpected in this<br />
manner.</p></blockquote>
<p>It&#8217;s not the biases in the analysis that I worry about; data can always be reanalyzed with different assumptions. It&#8217;s that something important might slip past the cuts that they need to make, and never get recorded.</p>
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		<title>By: WL</title>
		<link>http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/comment-page-1/#comment-60</link>
		<dc:creator>WL</dc:creator>
		<pubDate>Thu, 04 Aug 2005 20:06:16 +0000</pubDate>
		<guid isPermaLink="false">http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/#comment-60</guid>
		<description>Well I can tell what happened, to the extent I was in the lectures.
At any rate I learned more than what I had expected. Two points I, an outsider in this business, found somewhat baffling are:

1) It won&#039;t be easy to identify (once LHC is running) what kind of
supersymmetric standard model it is, if at all. There is a many-to-one
map, ie, one and the same set of given experimental data tends to
match many quite different discrete choices of parameters of the
supersymmetric standard model. This is partly because for a hadronic
collider, there are very many intermediate processes between the
original event and what you actually measure, to obscure the picture.
It seems to me that in order to do a thorough job, an enormous
effort plus luck will be necessary in order to meaningfully disentangle
the data.

2) It seems that most if not all of the analysis software is tuned
for the MSSM and variations thereof. On top of that, each of the
groups seem to have their own class of pet models they focus on. I
wonder how one could possibly find something unexpected in this
manner.  I sensed a firm belief in &quot;string inspired&quot; MSSM&#039;s (as if
there would be such a thing) and there was even the notion of
&quot;scanning the M-theory parameter space&quot;. I just hope that our
experimental collegues are independent enough such as not to be too
biased in favor what certain theoreticians tell them.</description>
		<content:encoded><![CDATA[<p>Well I can tell what happened, to the extent I was in the lectures.<br />
At any rate I learned more than what I had expected. Two points I, an outsider in this business, found somewhat baffling are:</p>
<p>1) It won&#8217;t be easy to identify (once LHC is running) what kind of<br />
supersymmetric standard model it is, if at all. There is a many-to-one<br />
map, ie, one and the same set of given experimental data tends to<br />
match many quite different discrete choices of parameters of the<br />
supersymmetric standard model. This is partly because for a hadronic<br />
collider, there are very many intermediate processes between the<br />
original event and what you actually measure, to obscure the picture.<br />
It seems to me that in order to do a thorough job, an enormous<br />
effort plus luck will be necessary in order to meaningfully disentangle<br />
the data.</p>
<p>2) It seems that most if not all of the analysis software is tuned<br />
for the MSSM and variations thereof. On top of that, each of the<br />
groups seem to have their own class of pet models they focus on. I<br />
wonder how one could possibly find something unexpected in this<br />
manner.  I sensed a firm belief in &#8220;string inspired&#8221; MSSM&#8217;s (as if<br />
there would be such a thing) and there was even the notion of<br />
&#8220;scanning the M-theory parameter space&#8221;. I just hope that our<br />
experimental collegues are independent enough such as not to be too<br />
biased in favor what certain theoreticians tell them.</p>
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		<title>By: Mark</title>
		<link>http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/comment-page-1/#comment-59</link>
		<dc:creator>Mark</dc:creator>
		<pubDate>Thu, 04 Aug 2005 19:16:43 +0000</pubDate>
		<guid isPermaLink="false">http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/#comment-59</guid>
		<description>I think we have to wait a few months until they&#039;ve finished and release the results.</description>
		<content:encoded><![CDATA[<p>I think we have to wait a few months until they&#8217;ve finished and release the results.</p>
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		<title>By: Alejandro Rivero</title>
		<link>http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/comment-page-1/#comment-58</link>
		<dc:creator>Alejandro Rivero</dc:creator>
		<pubDate>Thu, 04 Aug 2005 19:01:13 +0000</pubDate>
		<guid isPermaLink="false">http://blogs.discovermagazine.com/cosmicvariance/2005/07/18/the-lhc-olympics-and-the-mysteries-of-mass/#comment-58</guid>
		<description>So what happened?</description>
		<content:encoded><![CDATA[<p>So what happened?</p>
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