{"id":2887,"date":"2010-04-20T11:05:42","date_gmt":"2010-04-20T15:05:42","guid":{"rendered":"http:\/\/www.math.columbia.edu\/~woit\/wordpress\/?p=2887"},"modified":"2010-04-26T17:10:44","modified_gmt":"2010-04-26T21:10:44","slug":"tevatron-vs-lhc","status":"publish","type":"post","link":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/?p=2887","title":{"rendered":"Tevatron vs. LHC"},"content":{"rendered":"

The news from Fermilab is that the Tevatron has set a new luminosity record, with a store last Friday that had an initial luminosity of 4.04 x 1032<\/sup>cm-2<\/sup>s-1<\/sup>, or, equivalently, 404 inverse microbarns\/sec. For more about this, see a new posting<\/a> from Tommaso Dorigo, where someone from Fermilab writes in to comment that they’re not quite sure why this store went unusually well.<\/p>\n

Over in Geneva, commissioning of the LHC continues. There, the highest initial luminosity reported by ATLAS is 2.3 x 1027<\/sup>cm-2<\/sup>s-1<\/sup>, or 200,000 times less than the Tevatron number. I haven’t seen a recent number for the total luminosity delivered by the LHC to the experiments so far, but I believe it’s a small number of hundreds of inverse microbarns. The Tevatron is producing more collisions in one second than the LHC has managed in the three weeks since first collisions.<\/p>\n

The current plan for the LHC is to devote most of the rest of 2010 to increasing the luminosity of the machine, with a goal of reaching something somewhat lower than the Tevatron luminosity (1-2 x 1032<\/sup>cm-2<\/sup>s-1<\/sup>) by the end of the year. Then the plan is to run flat out at this luminosity throughout 2011, accumulating data at the rate of about 100 pb-1<\/sup>\/month, and ending up with a total of 1 fb-1<\/sup>. The hope is that this will allow them to be competitive for some measurements with Fermilab, the lower luminosity compensated by the advantage of a factor of 3.5 in beam energy that they now enjoy. <\/p>\n

The Tevatron has already produced over 8 fb-1<\/sup> of data, and the current plan is to run the machine through the end of FY 2011, reaching at least 10 fb-1<\/sup>, and then shut it down for good. The LHC is supposed to go into a long shutdown throughout 2012, not coming back into operation until 2013. Even if all goes well, it likely will not have accumulated enough data to decisively compete with the Tevatron until late 2013 or 2014. Under the circumstances, it’s hard to believe that there aren’t plans being proposed at Fermilab to keep the Tevatron running for several more years, until 2014. The machine should then be able to end up with a total of 15-20 fb-1<\/sup> worth of data, which could be enough to allow them to see evidence of the Higgs at the 3 sigma level over the entire possible mass range.<\/p>\n

Shutting down the Tevatron as planned would free up funds for other experiments, and free parts of the accelerator complex for use by neutrino experiments. It will be interesting to see whether instead of this, the decision gets made to go for a bid to outrace the LHC to the Higgs and other high energy frontier physics over the next few years.<\/p>\n

Update<\/strong>: The integrated luminosity seen by the ATLAS detector for the current run so far is about 400 inverse microbarns, 350 at CMS (where they have 300 worth of recorded data).<\/p>\n

Update<\/strong>: This morning the LHC has started delivering collisions with stable squeezed beams to the experiments, initial luminosity 1.1-1.2 x1028<\/sup>cm-2<\/sup>s-1<\/sup>.<\/p>\n

Update<\/strong>: Integrated luminosity delivered to each experiment at the LHC is now up to around 1000 inverse microbarns.<\/p>\n","protected":false},"excerpt":{"rendered":"

The news from Fermilab is that the Tevatron has set a new luminosity record, with a store last Friday that had an initial luminosity of 4.04 x 1032cm-2s-1, or, equivalently, 404 inverse microbarns\/sec. For more about this, see a new … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[9],"tags":[],"class_list":["post-2887","post","type-post","status-publish","format-standard","hentry","category-experimental-hep-news"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2887","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2887"}],"version-history":[{"count":16,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2887\/revisions"}],"predecessor-version":[{"id":2903,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2887\/revisions\/2903"}],"wp:attachment":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2887"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2887"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2887"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}