A Quantum Diaries Survivor

That's because you never learn anything new.[By the way: if you were coming here to learn the solution of my riddle about the mysterious plot I posted here yesterday, be patient - I will publish an answer tomorrow on that issue.]

After the disturbance created by the Higgs rumour in ATLAS, I think we can go back to normal business - in this case, keeping my word on discussing things that were left hanging.Your response to my small riddle was quite good, forcing me to provide a timely and exhaustive explanation of what is in the plot I posted a few days ago.

The Xenon 100 collaboration has finally released the results of their data analysis, and the results are saying that there is no Dark Matter in sight so far. Since we live in an age where time is precious, I think many of you are only interested in the bottomline. I can give it to you straight away, in the form of the plot which summarizes the results. Xenon 100 finds three events compatible with a dark matter signal, with a background expected from more mundane sources amounting to 1.8+-0.6 events. The limit they extract on the cross section versus mass of the hypothetical particle are shown below by a thick blue curve, which cuts into the flesh of the preferred parameter space of constrained minimal supersymmetric theories (in grey), pushing them farther away.

In the comments thread of one of the posts I wrote recently, where I discussed the new tentative signal of a new jet-decaying particle discovered by the CDF collaboration in their data, a reader asked me if hadronic signals of single vector bosons had been seen before by CDF.

Given the wide interest (about 20k readers in a day) that the new article by the CDF collaboration has attracted (see my original post here), I think I should collect in a separate post some auxiliary information, concerning past searches which might have been sensitive to such a signal in the past.

UPDATE (4/7): I posted a link to a nice animated GIF which shows the (approximate) effect of scaling up the MC/data jet energy scale factor on the CDF new particle signal. See here.UPDATE (4/7): I added some considerations on the tentative CDF signal in a separate post today (4/7). You can find there a comparison with older semileptonic diboson searches at CDF and DZERO.

I have recently dusted off an algorithm I had invented eight years ago, one I dubbed "Hyperball algorithm". It might come handy for predicting the b-tagging rate in CMS events with jets, for an analysis I am thinking of doing. Since saying more would violate a dozen rules so let's leave it at that, and let me instead describe the old idea... Just for fun.Predictions for the Higgs at the Tevatron

It has been a while since I last wrote about results from the DZERO collaboration, and I am happy to be given a chance to do so by my casual Monday morning browsing of the most recent Arxiv preprints.

The CDF collaboration sent to the preprint arxiv a new paper a few days ago. In it, they report on a measurement of the mass difference of top and anti-top quarks. The result would not be worth discussing in detail, if it did not show a 2-sigma discrepancy which might be the first hint of a CPT violation. So let me discuss it here.

... Not really.What startled me most was that a colleague of mine at the University of Padova even sent a message to my departments' mailing list, saying that the new result is very important. But it clearly isn't! In fact, the exclusion at 95% CL in the range of Higgs boson masses that CDF and DZERO could put together from the analysis of additional data is almost exactly the same as the one that they published last Summer.But maybe I should make a step back and explain the matter from the start, to let you judge by yourself the relevance of the new Tevatron bounds on the rate of Higgs boson production in proton-antiproton collisions.CDF and DZERO are analyzing the proton-antiproton collisions at 2 TeV that the Tevatron collider is producing since 2001.

Readers of this blog know that I often discuss here the latest results of searches of Supersymmetric (SUSY) particles -nowadays furthered by the CDF and DZERO experiments at the Fermilab Tevatron collider, and by the ATLAS and CMS experiments at the CERN LHC.

I just became aware of a letter that is being sent to a couple of US Senators by a large and illustrious collection of scientists, and I decided to put my signature below it. The letter is clear and I will not comment it here - suffices to just paste it here. By the way, I do not think that more signatures are necessary to it, but if you agree with the contents and wish to participate your support, please do so by adding your name below, in the comments thread. It will just take you thirty seconds of your valuable time, but it might have an impact here too.-----------Senator Dianne FeinsteinChairmanEnergy& Water Appropriations Subcommittee SenatorLamar Alexander