tag:blogger.com,1999:blog-2846514233477399562.post5170979577037372224..comments2024-01-08T09:37:04.406+01:00Comments on RÉSONAANCES: LHC seriously into Higgs searchesJesterhttp://www.blogger.com/profile/08947218566941608850noreply@blogger.comBlogger8125tag:blogger.com,1999:blog-2846514233477399562.post-60212525518958157412011-04-04T21:56:05.700+01:002011-04-04T21:56:05.700+01:00That bump is suspiciously close to (M_J/Psi + M_Up...That bump is suspiciously close to (M_J/Psi + M_Upsilon)/2. The three-step structure further makes me think it's the three narrow Upsilons contributing, where two muons are missed.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-2846514233477399562.post-87247467486649011412011-03-16T22:14:26.322+01:002011-03-16T22:14:26.322+01:00What about the peaks at about 650 GeV and 1.1 TeV ...What about the peaks at about 650 GeV and 1.1 TeV in the left-hand graph on page 10 of <a href="http://indico.in2p3.fr/getFile.py/access?contribId=1&sessionId=4&resId=0&materialId=slides&confId=4403" rel="nofollow">Doug Gingrich's talk</a> at Moriond? (Not clear if this is looking for an excited quark or an axigluon.) There are no error bars but if we assume that each dot on the curve represents a "bin", then for sigma x Acceptance around 10 pb then with 36 per pb of data, wouldn't each dot represent around 360 events? In which case the error bars will be around 1/20 of the measured values, so quite small. And the dots follow a smooth curve, so the peaks won't be statistical fluctuations.<br /><br />If the peaks are somehow being caused by the "acceptance", how could that happen when the heaviest observed SM object is not much heavier than 1/4 of 640 GeV?<br /><br />There are also events way above background at around 700 GeV and 900 GeV in the first and second graphs respectively on page 15, High Mass Dilepton Resonances (just one event in the 2nd graph, but there should be nothing there). These are clearly reflected in the large bumps in the observed limits on page 16.<br /><br />There is also a large peak at 400 GeV in the dilepton searches on page 4 of <a href="http://indico.in2p3.fr/getFile.py/access?contribId=23&sessionId=4&resId=0&materialId=slides&confId=4403" rel="nofollow">Francesco Santanastasio's talk</a>, but it doesn't coincide with any of the bumps on page 16 of the ATLAS talk.Chris Austinhttp://chrisaustin.info/noreply@blogger.comtag:blogger.com,1999:blog-2846514233477399562.post-44702718252971405342011-03-16T17:45:31.166+01:002011-03-16T17:45:31.166+01:00Alternatively, the blanking of 9-11 could have bee...Alternatively, the blanking of 9-11 could have been made by the Islamists... I was defending my PhD on that morning.Luboš Motlhttps://www.blogger.com/profile/17487263983247488359noreply@blogger.comtag:blogger.com,1999:blog-2846514233477399562.post-18082129130223519532011-03-16T11:41:54.159+01:002011-03-16T11:41:54.159+01:00Exactly, there are Upsilon resonances in that regi...Exactly, there are Upsilon resonances in that region, so it would be hard to search for new physics resonances there.Jesterhttps://www.blogger.com/profile/08947218566941608850noreply@blogger.comtag:blogger.com,1999:blog-2846514233477399562.post-48316786313198559772011-03-16T11:01:22.345+01:002011-03-16T11:01:22.345+01:00Hmmm... this is probably a stupid question, but wh...Hmmm... this is probably a stupid question, but why is there a blanked out at region 9-11 GeV?<br /><br />Is it because of background from B decays?Allanach Reloadedhttp://users.hepforge.org/~allanach/noreply@blogger.comtag:blogger.com,1999:blog-2846514233477399562.post-46192083771308116882011-03-15T22:18:26.151+01:002011-03-15T22:18:26.151+01:00Oh, I see, here it was decaying to two muons which...Oh, I see, here it was decaying to two muons which an LSP should't do, either. ;-)Luboš Motlhttps://www.blogger.com/profile/17487263983247488359noreply@blogger.comtag:blogger.com,1999:blog-2846514233477399562.post-17571635536101233872011-03-15T22:09:11.616+01:002011-03-15T22:09:11.616+01:00The 7 GeV dark-matter bump is surely interesting g...The 7 GeV dark-matter bump is surely interesting given the fact that <a href="http://motls.blogspot.com/2010/02/cogent-hundreds-of-dark-matter.html" rel="nofollow">COGENT has almost claimed a 7-11 GeV dark matter particle</a>.<br /><br />Michael: of course that if it is a dark matter particle, it is only produced in pairs because - e.g. a bino - it is R-parity-odd so you can't create it as a simple resonance peak from R-parity-even initial states.Luboš Motlhttps://www.blogger.com/profile/17487263983247488359noreply@blogger.comtag:blogger.com,1999:blog-2846514233477399562.post-70921401891831426422011-03-15T18:44:47.082+01:002011-03-15T18:44:47.082+01:00You're right that the LHC can already probe so...You're right that the LHC can already probe some though not all interesting Higgs scenarios. The superior detectors mean better tau-ID, leading to these impressive results.<br /><br />Note that the CMS result is a bit better than the ATLAS one. It will be interesting to understand why.<br /><br />Also, one sees here the dramatic difference between the popular "CLs" method and the controversial "PCL" method in the ATLAS plot. Kudos to ATLAS for providing both curves.<br /><br />Concerning the bump at 7 GeV - searches for these light resonances were conducted by CDF and no such signal was observed. So unless a new light particle is produced <i>only</i> as the decay product of some very heavy state, these data contradict results from CDF.<br /><br />MichaelAnonymousnoreply@blogger.com