Hey, I'm Shena!
This is a post that is part of a special Blog Hop! 12:10 pm: The shutdown of the Tevatron should be viewed as a part of the bigger program of shutting down fundamental research in the US. Make sure you fold the same points down on each pinwheel, so they match each other. Nowadays, with social media and online advertising, as little as 1% can make a huge difference. My little ship looks a lot smarter than she did. Although 10k looks like whole lotta events, Higgs signatures are notoriously difficult to search. They are a great place to get away from that initial dullness by making the experience a bit simpler and guiding the player to think in the correct manner about how the game works. Last week, the Chamonix workshop once again proved its worth as a place where all the stakeholders in the LHC can come together, take difficult decisions and reach a consensus on important issues for the future of particle physics. I had wondered on Wednesday whether there was a place in My eBay where I could keep track of the eBay Bucks. There is a good excuse. I have already had five sales on Bonanza since April 1, so April is off to a good start. For this and other reasons, neither Tevatron nor the LHC has good prospects of discovering the Higgs, unless in lucky circumstances (e.g. production cross section larger than in the standard model, or Higgs mass sitting close to the sweet spot of 160 GeV). 9:50 am: Except for the top quark, what were the most important findings of the Tevatron? In particular, it seems that neither the standard model top quark, nor a difference of jet energy scales between quark and gluon jets can be responsible for the excess. However, in that particular case the discovery is not guaranteed because of the large standard model background, for example from the top quark pair production. In this case the standard model background is almost non-existent, so 25 events might be enough to claim a discovery. That might be an asset, because they are a priori sensitive to a variety of dark matter particles, whether scattering elastically or inelastically, whether scattering on nucleons or electrons, and so on. Nevertheless, prompted by a commenter, I thought it might be useful to balance a bit and describe a more trivial explanation of the DAMA signal that involves a systematic effect rather than dark matter particles. In this decade, DAMA has been the main source of inspiration to extend dark matter model building beyond the simple WIMP paradigm, in particular inelastic dark matter was conceived that way. One important source of the background is a contamination of DAMAs sodium-iodine crystals with radioactive elements like Uranium 238, Iodine 129 and Potassium 40. The last one is the main culprit because some of its decay products have the same energy as the putative DAMA signal. Now, look at the spectrum of the time dependent component of the signal where DAMA claims to have found evidence for dark matter. More than once I wrote in this blog about crazy theoretical ideas to explain the DAMA modulation signal. 5) Limitless Cross Exposure and Blog Ideas. Blog readers know this since ages, but today the news was made official. We know comparing Facebook to other online discussion mediums, that people generally stop acting like complete douche bags when theyre using their real name. If there are any specific posts you would like me to remove your comments from just let me know and Ill be happy to help. See the list at Tommasos blog.9:30am: Tevatrons observation of the anomalous top-antitop forward-backward asymmetry is currently the strongest hint that there may be new physics. It must be a more subtle detector effect, or new physics. 11:05 am: The Tevatron has 3-4 more hours to live. For the next 2 hours Ill listen to the summary of the most important results obtained by the D0 collaboration. Thursday CDF released an online note describing the latest update based on 7.3 fb-1 of data. 2j events at CDF. For example, one promising discovery channel at the LHC is when the Higgs decays into two photons, which happens roughly twice per thousand events for a 120 GeV Higgs. Make the Z mass 1.3 TeV and the number of dilepton events at the LHC drops to 5. The final lesson to take home: the LHC can be lucky if Tevatron is extremely unlucky. Helen Edwards, who was the lead scientist for the construction of the Tevatron in the 1980s, will terminate the final store in the Tevatron by pressing a button that will activate a set of magnets that will steer the beam into the metal target. The general lesson is that the LHC will be competitive in measuring the standard model processes, but it cannot beat the Tevatron black and blue. If the model they are using has any theoretical motivation, Randall didnt mention it.