{"id":8174,"date":"2015-12-14T19:43:38","date_gmt":"2015-12-15T00:43:38","guid":{"rendered":"http:\/\/www.math.columbia.edu\/~woit\/wordpress\/?p=8174"},"modified":"2015-12-15T12:24:00","modified_gmt":"2015-12-15T17:24:00","slug":"lhc-run-2-first-results","status":"publish","type":"post","link":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/?p=8174","title":{"rendered":"LHC Run 2 First Results"},"content":{"rendered":"

First results<\/a> using the full data from Run 2 at 13 TeV will be presented tomorrow at CERN at 15:00 Geneva time, with a live webcast available here<\/a>. For some relevant commentary, see Tommaso Dorigo<\/a> and Matt Strassler<\/a>. <\/p>\n

Among relatively reliable rumor sources, Jester is tweeting<\/a> about a supposed excess at 750 GeV in the diphoton spectrum. We’ll see tomorrow, but the problem with this is that it would be hard to understand why such a thing didn’t show up in Run 1 at 8 TeV. Tommaso explains why it is only at higher masses that one expects the Run 2 data to be competitive with that from Run 1, and suggests that what to look for is a 2 TeV excess in the dijet spectrum, since there were already hints of such a thing in the Run 1 data.<\/p>\n

Matt describes 13 TeV results recently published by the ATLAS and CMS groups looking for exotic behavior at very high mass (predicted for instance by various theories of extra dimensions). Nothing there. <\/p>\n

One other thing to look for is whether Gordon Kane will get his Nobel Prize. He’s predicting a 1.5 TeV gluino, with current limits around 1.4 TeV, and this year’s Run 2 data perhaps enough to push those up a bit. It may though be that such analyses will be among those that take longer, not appearing until the Moriond conference in March.<\/p>\n

Update<\/strong>: CMS went first, results now publicly available here<\/a>. Tommaso was pulling our leg, the 2 GeV Run 1 excesses have gone away. There is a diphoton excess at 766 GeV, but an unimpressive one (2.6 sigma locally, 1.2 sigma with look elsewhere effect).<\/p>\n

Gluino mass limits have moved up, some as high as 1.7 TeV. Presumably Kane is now at work on new string theory predictions.<\/p>\n

Bottom line: nothing beyond the SM so far.<\/p>\n

Update<\/strong>: ATLAS next. No gluinos up to 1.8 TeV. 2.2 sigma for the 2 TeV excess that CMS doesn’t see.<\/p>\n

They also see an excess in diphotons around 750 GeV, 3.6 sigma local significance, 1.9 sigma with look-elsewhere. So, starts to look interesting if combined with CMS, the rumor was right. They also reanalyzed the Run 1 data, nothing there at 750 GeV, no combination of Run 1 and Run 2.<\/p>\n

Results available here<\/a>.<\/p>\n

Bottom line: only thing interesting is the possible 750 GeV diphoton excess. One can predict a flood of theory papers with models predicting such a thing. Will have to wait until at least next summer though to see if this gets confirmed or goes away.<\/p>\n

Commentary from Matt Strassler here<\/a>.<\/p>\n

Update<\/strong>: As expected, best explanation and discussion of the implications of the diphoton excess is from Jester, see here<\/a>.<\/p>\n

Reasons to be excited: naively combining CMS and ATLAS gives something of 4 sigma significance, people are making the analogy with the early Higgs signal. Reasons to be less excited: in the case of the early Higgs signal, the tentative signal was what was expected from the Higgs, and we had very good reasons to believe there was a Higgs roughly in that mass range. Here I know of no well-motivated models that predict this: extraordinary claims require extraordinary evidence, and this is not that.<\/p>\n","protected":false},"excerpt":{"rendered":"

First results using the full data from Run 2 at 13 TeV will be presented tomorrow at CERN at 15:00 Geneva time, with a live webcast available here. For some relevant commentary, see Tommaso Dorigo and Matt Strassler. Among relatively … 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-8174","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\/8174","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=8174"}],"version-history":[{"count":12,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/8174\/revisions"}],"predecessor-version":[{"id":8180,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/8174\/revisions\/8180"}],"wp:attachment":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=8174"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=8174"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=8174"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}