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January | 2014 | Collider Blog
https://muon.wordpress.com/2014/01
Archive for January, 2014. Inclusive W and Z cross sections. Quark density on the basis of inclusive cross section measurements. I’ll return to this result in a future post. Are nearly as precise as the theoretical predictions, whose errors are dominated by the PDF uncertainties. We knew, back in 2011, that a new era of electroweak physics had begun. It is even more interesting to plot the W. Cross section against the W. Cross section, because the asymmetry between W. In a low pile-up configuration in or...
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CMS resolves states with a mass difference of 19 MeV | Collider Blog
https://muon.wordpress.com/2014/09/27/cms-resolves-states-with-a-mass-difference-of-19-mev
CMS resolves states with a mass difference of 19 MeV. September 27, 2014 at 4:56 pm. This week the CMS Collaboration released a paper reporting the measurement of the ratio of production cross sections for the χb2(1P) and the χb1(1P) heavy meson states ( arXiv:1409.5761. The motivation stems from the theoretical difficulties in explaining how such states are formed, but for me as an experimenter the most striking feature of the analysis is the impressive separation of the χ states. The mass of the χb...
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October | 2013 | Collider Blog
https://muon.wordpress.com/2013/10
Archive for October, 2013. Nice, short video on US contributions to CERN Science. I just heard about a youtube video written by Don Lincoln about the role the United States plays in CERN science – specifically, the LHC. You can view it here:. Apparently Ernie Monitz, the new Secretary of Energy, linked this to his facebook page: https:/ www.facebook.com/ErnestJMoniz/posts/222609781237091. October 19, 2013 at 3:23 pm. Blank on the Map. Life on the Lattice. Shores of the Dirac Sea. The CMS kinematic edge.
muon.wordpress.com
November | 2012 | Collider Blog
https://muon.wordpress.com/2012/11
Archive for November, 2012. Higgs couplings to fermions and massive vector bosons. Let’s review the tests of the Higgs couplings to fermions and massive vector bosons completed by CMS and ATLAS. V, while the Higgs coupling to the fermions goes as M. V, where v is the Higgs vacuum expectation value (v = 246 GeV). Could there be a new physics effect that modifies these tree-level couplings? CMS and ATLAS have taken all their Higgs data and performed a fit with two free scale factors: κ. 0 but that one is n...
muon.wordpress.com
June | 2012 | Collider Blog
https://muon.wordpress.com/2012/06
Archive for June, 2012. CMS puts new constraints on Dark Matter. CMS recently released a paper on the search for monojets ( arXiv:1206.2664. 25-June-2012). Normally one thinks of monojets (events with one energetic jet and large missing energy or “MET'') in the context of supersymmetry or maybe large extra dimensions. But this paper follows a treatment first published by CDF ( arXiv:1106.4775. At masses inaccessible to most direct-detection DM searches. The non-observation of monojets implies upper limit...
muon.wordpress.com
October | 2014 | Collider Blog
https://muon.wordpress.com/2014/10
Archive for October, 2014. The CMS kinematic edge. Does CMS observe an excess that corresponds to a signal for Supersymmetry? This week a paper appeared with the statement “…CMS has reported an intriguing excess of events with respect to the ones expected in the SM” (Huang and Wagner, arXiv:1410.4998. And last month another phenomenology paper appeared with the title “Interpreting a CMS lljjpTmiss Excess With the Golden Cascade of the MSSM” (Allanach, Raklev and Kvellestad arXiv:1409.3532. The best fitte...
muon.wordpress.com
March | 2012 | Collider Blog
https://muon.wordpress.com/2012/03
Archive for March, 2012. Last week I was reading Science. And I came across a touching editorial by Alan Alda – the actor. His concern is a basic one that nearly all of us share: how do we connect in a fundamentally human way to non-scientists, especially children, about science? If a child asks you: What is a candle flame? So, how would you answer the child in a way that avoids those pitfalls? March 21, 2012 at 8:44 pm. Anyway, this plot says it all:. TOF of neutrinos compared to the TOF for light.
muon.wordpress.com
February | 2014 | Collider Blog
https://muon.wordpress.com/2014/02
Archive for February, 2014. Z decays to four leptons. A bit more than a year ago I was pleased to see a clear signal from CMS for the decay of Z bosons to four leptons. Of course there are literally millions of recorded Z decays to two leptons (e. Used for standard model physics studies, lepton efficiency measurements, momentum/energy scale determinations and detector alignment. But Z→4L is cuter and of some intrinsic interest, being relatively rare. Ie, arXiv:1210.3844. Most of the events consist, in es...
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