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[Rivet] Neutrino question - once againDavid Grellscheid david.grellscheid at durham.ac.ukTue May 3 15:59:21 BST 2016
Hi, thanks for your replies! I'll try to move ahead in the same way as in the W-Finder case then, assuming that MET is the same as the sum of the two neutrinos. Since I can assign any value for the invariant mass in that case, I'll just assume that (iii) is a no-op, and compare before/after on the Standard Model. See you, David On 03/05/16 15:36, Jonathan Butterworth wrote: > Hiya > > Unfortunately the fiducial definition in the paper (section 4.1) is what > matters, because the detector level cuts will have been "corrected" to > this using SM Monte Carlo. > > I think this is the same as the paper, that is: > > (i) two same-flavour opposite-sign electrons or muons, each with pT > > 20 GeV, |η| < 2.5, with ∆R(+, −) > 0.3, > > (ii) dilepton invariant mass close to the Z boson mass: 76 < m+− < 106 > GeV, > > (iii) dineutrino invariant mass close to the Z boson mass: 66 < mνν ̄ < > 116GeV, > > (iv) no jet with pjT >25 GeV and |ηj| < 4.5,and > > (v) (|pν ν ̄ − pZ |)/pZ < 0.4 and −pν ν ̄ · pZ /pZ > 75 GeV. > > I guess this is what is implemented in Rivet though I haven't checked. > > (iii) is clearly problematic. I guess it was put in because it is > physically well-defined and better than saying "a Z", even though in > practice it is unmeasurable. Not good, something to highlight for future > measurements. > > I think all the other cuts can be implmented ok just using observable > missing ET. I guess if we evaluate the effect of (iii) on ZZ SM MC, that > will tell us how important it is (that is the correction which will have > been applied by ATLAS). My guess is not very important... > > Cheers, > Jon > > > On 03/05/2016 15:05, Holger Schulz wrote: >> Hi, >> >> >> I had a look into the corresponding internal document >> (https://cds.cern.ch/record/1471026 --- section 3.3). >> >> There is a definition given that makes a lot more sense. >> >> I don't want to breach ATLAS secrecy and things so I don't know how to >> proceed from >> here. >> >> I probably could give you the names of the editors, will check. >> >> >> Holger >> >> On 03/05/16 14:31, David Grellscheid wrote: >>> Hi all, >>> >>> what's our justification again for being allowed to use two >>> distinguishable truth neutrinos in ATLAS_2012_I1203852 == >>> http://arxiv.org/pdf/1211.6096.pdf ? >>> >>> I'll need to rewrite that section along the lines of the W-Finder >>> fixes, to assume generic invisibles rather than standard model >>> neutrinos. Can someone on ATLAS please help me to interpret this >>> statement from the paper in terms of measurables? >>> >>> "dineutrino invariant mass close to the Z boson mass" >>> >>> The event selection section is very brief on how I get to the Z-nunu >>> candidate in the first place. >>> >>> Thanks, >>> >>> David >>> _______________________________________________ >>> Rivet mailing list >>> Rivet at projects.hepforge.org >>> https://www.hepforge.org/lists/listinfo/rivet >> >> _______________________________________________ >> Rivet mailing list >> Rivet at projects.hepforge.org >> https://www.hepforge.org/lists/listinfo/rivet >
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