{"id":428,"date":"2006-09-22T19:00:57","date_gmt":"2006-09-23T00:00:57","guid":{"rendered":"http:\/\/dragocolosus.dyndns.org\/?p=428"},"modified":"2026-08-10T07:55:47","modified_gmt":"2026-08-10T12:55:47","slug":"observation-of-bs-bsbar-oscillations-core-of-my-tenure-case","status":"publish","type":"post","link":"https:\/\/dragocolosus.dyndns.org\/?p=428","title":{"rendered":"Observation of Bs-Bsbar Oscillations — Core of my Tenure Case"},"content":{"rendered":"

The observation of Bs mixing (that is how we always referred to it) was more like an afterthought for me. My real goal for the Tevatron and the CDF experiment was supposed to be the Higgs boson search. It would take a while to have enough data therefore I thought of doing something interesting but reasonably quickly. Bs mixing seemed to be the perfect topic: a great physics goal as not much was known about the real value and it would be very plausible if something would not agree with the standard model as the CP sector was and still is suspect as it does not allow for an explanation of the observed matter-antimatter asymmetry. First studies with our trigger simulation (GenTrig) clearly indicated that it was doable pretty quickly. We estimated half a year but the real results with all the assumed parameters suggested that we should have enough data within 2 months.<\/p>\n

Well it came differently as everybody knows today. We started data taking seriously in April 2001 and went through a depressing startup of the Tevatron in terms of the delivery of data. The silicon detector, an integral part of the analysis, would not work even close to what we were estimating and the two-track trigger was very sensitve to the beam positioning, which was on our scale far off its nominal position. These three main factor turned the quick analysis into a marathon which streched out until finally in September 22, 2006 I had the honour to announce the observation of Bs mixing at the required 5 standard deviation significance<\/a>. We had a key crew of about 15 people pulling this analysis through with lots of people signing on but not contributing at an equivalent level (there were about 70 registered people).<\/p>\n

We literally prepared this analysis through tens of precursor analyses and publications with thousands of pages of documentation. We spent probably several months in meetings presenting discussion and sometimes fighting. Lots of allnighters were pulled by many many people in the core team and we had the time of our life, in particular as the result just came together when I had to leave and start serious involvement in CMS. “Das Glueck ist mit dem tuechtigen” as I always say. Anyway, this photo has been taken when I announced our observation for the first time to the public, it was a very emotional experience for me.<\/p>\n

\"\"<\/a>
Christoph Paus announced the discovery at Friday’s Wine & Cheese Seminar.<\/figcaption><\/figure>\n

The key scientific picture is of course this one which clearly shows that at a frequency around 17.8\/ps the data suggests an amplitude of one significantly different from an amplitude of zero which would be consistent with no oscillations. Enjoy, this is the result of very hard and highly organized effort and an analysis masterpiece.<\/p>\n

\"\"<\/a>
Oscillation signal at about 17.8\/ps (picture includes division by 2pi) when the measured amplitude is consistent with one and inconsistent with zero.<\/figcaption><\/figure>\n

The life recording of the event can be found here<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

The observation of Bs mixing (that is how we always referred to it) was more like an afterthought for me. My real goal for the Tevatron and the CDF experiment was supposed to be the Higgs boson search. It would take a while to have enough data therefore I thought of doing something interesting but … <\/p>\n

Continue reading “Observation of Bs-Bsbar Oscillations — Core of my Tenure Case”<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9],"tags":[],"class_list":["post-428","post","type-post","status-publish","format-standard","hentry","category-mit"],"_links":{"self":[{"href":"https:\/\/dragocolosus.dyndns.org\/index.php?rest_route=\/wp\/v2\/posts\/428","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/dragocolosus.dyndns.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/dragocolosus.dyndns.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/dragocolosus.dyndns.org\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/dragocolosus.dyndns.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=428"}],"version-history":[{"count":9,"href":"https:\/\/dragocolosus.dyndns.org\/index.php?rest_route=\/wp\/v2\/posts\/428\/revisions"}],"predecessor-version":[{"id":9648,"href":"https:\/\/dragocolosus.dyndns.org\/index.php?rest_route=\/wp\/v2\/posts\/428\/revisions\/9648"}],"wp:attachment":[{"href":"https:\/\/dragocolosus.dyndns.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=428"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dragocolosus.dyndns.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=428"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dragocolosus.dyndns.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=428"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}