I once was an active chessplayer, but work duties have long taken tournaments off my plate - I simply do not have the time to sit through long hours of chess battles. So I play blitz online on chess.com (my handle is "tommasodorigo", in case you wondered).
Do you remember the dijet mass bump found by CDF in W plus jets events ? That signal, whose significance exceeded four standard deviations, had everybody around go crazy for a while.
As a 20-year-long (ok well, 19) member of the CDF collaboration, I am very proud of this wonderful experiments' accomplishments in all areas of high-energy physics, from exotic searches to Higgs searches, from top quark measurements to b-physics measurements, and what not. CDF is a landmark in experimental physics, and the longest-lasting physics experiment ever. But it is not foulproof - nobody is in this wild world of statistical flukes and impossible-to-unearth systematic effects.
While experimentalists gathered in Grenoble present the latest results on High-Energy Physics searches and measurements, phenomenologists like Sven Heinemeyer are working 24/7 to update the picture of the breathing space left for Supersymmetry, in the light of the most recent searches.You of course do not need to be reminded that Supersymmetry is not a theory but a framework, within which a host of possible manifestations of subnuclear physics are configurable based on the value of 120-or-so free parameters. Because of that, if one wants to discuss in detail what are the most likely versions of SUSY left on the table, and what is the value of the most representative and critical theory parameters, one needs more than paper and pencil.
In the last few days I described in some detail (here and here) the six searches for the Standard Model Higgs boson just produced by CMS, the experiment at the CERN Large Hadron Collider to which I proudly belong.
In my short summary of analyses recently published by CMS, yesterday I left out one which had not yet been released. It is the search for the "golden channel" of Higgs decay, the one which motivated the construction of detectors with large acceptance to energetic leptons: the decay to two Z bosons, with a subsequent decay of the Z's to two charged leptons each.
An orgy of new results has started. Let me just show a few of them concerning Higgs searches in CMS - I am on vacation after all, and I have little time left to comment these interesting new papers and plots after all the sunbathing and restaurants.Let us start with the Higgs search in the diphoton decay mode by CMS (paper here). With 1.09 inverse femtobarns of data, CMS has a pretty good reach even to this very rare decay mode of the Higgs boson. Let me remind you that only a handful every thousand Higgs particles decay into two photons, in the most favourable circumstances.
Impressive. If you had been seeking for top quarks in 4-inverse-picobarns datasets since 1992 as I have, and then rejoiced at the 7-event signal from which CDF extracted in 1994 mass and cross section of the long-sought sixth quark, you would now also be looking for adjectives upon having a look at the figures in the new CMS paper, which uses over one inverse femtobarn of proton-proton collisions to measure the tiny asymmetric kinematics of top quark pairs produced at the LHC.
This afternoon (2.30 PM Chicago time) Pat Lukens, an old-timer of the CDF experiment, will give a "wine and cheese" seminar at Fermilab on the new observation of a heavy baryon, of the family of baryons containing bottom quarks, which was still at large.The new particle, called "Xi_b^0", fits a hole in the group representation graph of ground-state baryons with J=1/2. You can see it in the graph on the right. Of all states in the middle level (ones containing one bottom quark) only the Xi_b^0 was still missing. By the way: none of the baryons of the top level have yet been observed.
Blogging from the whereabouts of one of the most beautiful places of the Mediterranean, Balos Beach (see picture), I wish to draw your attention today to one fun search that CMS produced on data collected in 2010: the one for gluinos in events with six jets.
I was waiting for the announcement in the Fermilab seminar of next Friday, but apparently despite I am still a member I am not well enough informed of what happens inside CDF, the experiment at the Tevatron proton-antiproton collider of Fermilab. So the paper is now public, and you can read the news in the Cornell arxiv: CDF sees an excess of muon pairs which is compatible with originating from the decay of B_s mesons.
While other sources (voluntarily not linked here, to avoid pissing off my collaborators) choose to be "on the news" these days, with a brand new exclusion plot of the Higgs boson obtained using almost one full inverse femtobarn of collisions which is not yet public but was made accessible by mistake on a Fermilab site, I will meekly point you out today to another result, which is by all means public and freely reproducible here (no reproach to Phil intended here -he acted in good faith and the fault is not his).
The DZERO collaboration has just produced an update of their analysis of the dimuon charge asymmetry using 9.0 inverse femtobarns of proton-antiproton collisions. The new result confirms the previously reported effect, raising the discrepancy with the Standard Model prediction to over four standard deviations.
