VBF workshop summary Andrey Korytov on behalf of

VBF workshop summary Andrey Korytov on behalf of all contributors Andrey Korytov (UF) VBF Workshop, Fermilab, June 17 -19, 2009 1

Overall Excellent overview of the current status VBF analyses per se (lots of good recent progress!) Pietro, Si, Efe, Bo, Haifeng, Jian, Youn, Anthony touching upon relevant reconstruction issues (e, mu, jet, MET) Pietro, Alexey, Alexi, Haifeng put in a broader context of the CMS/ATLAS/Tevatron efforts Chiara, Bruce, Alexey, Shuichi, Taylan, Krisztian Peters and spiced with some theory/phenomenology Dan, Dieter, Diogo, Bruce, Andre, Christoph Very inspiring discussions identifying questions requiring further studies and giving leads to possible ways of addressing them Great opportunity to get to know each other Andrey Korytov (UF) VBF Workshop, Fermilab, June 17 -19, 2009 2

Some benchmark numbers Channel LHC energy Signal (fb) Bkgd (fb) Si WW 2 l 2 v 10 Te. V 8. 3 6. 3 Efe WW 2 l 2 v (14 Te. V) (7. 2) (9. 7) Bo WW 2 l 2 v 10 Te. V 3. 8 4. 0 m. H=170 Haifeng WW lvjj 10 Te. V 3. 0 2. 3 m. H=170 Jian ZZ llvv 10 Te. V 0. 6 0. 8 m. H=400 Youn ZZ lljj 10 Te. V 1. 1 7. 7 m. H=400 m. H=170 m. H=160 (2007 study) Documentation: - AN notes? YES! by all means, please - by the end of summer? - with the full scrutiny (“blessing”) at the VBF Higgs meetings Andrey Korytov (UF) VBF Workshop, Fermilab, June 17 -19, 2009 3

Next… not well organized observations… Andrey Korytov (UF) VBF Workshop, Fermilab, June 17 -19, 2009 4

VBF with 2010 data SM Higgs H WW n n How much does it contribute to the exclusion sensitivity of an inclusive WW 2 l 2 v with 200 pb-1? If 5%, should we push for it? Fermiophobic h gg n n n do we need VBF signature or p. T(h) is enough? should be able to push the current limit (110 GEV) need to ramp up the effort h WW at low masses n need an estimate (we have all we need for that) Andrey Korytov (UF) VBF Workshop, Fermilab, June 17 -19, 2009 5

FJT selection many variations presented n can we have one cut-based benchmark so that all new “better” variations could be compared to it? jet p. T threshold: n n CMS: mostly 30 Ge. V; ATLAS: 20 Ge. V can we make a quantitative argument of how critical this threshold is? Are 25, 20 Ge. V thresholds worthwhile fighting for? Andrey Korytov (UF) VBF Workshop, Fermilab, June 17 -19, 2009 6

CJV selection uncertainties high p. T threshold is not really tagging an absence of colorexchange radiation low-p. T threshold is not really predictable n n n Instrumentation uncertainties Pythia vs Herwig: big difference? qq->qq. ZZ via VBF vs g-exchange: no difference? CJV vs TCV Any action items (besides talking to phenomenologists)? Andrey Korytov (UF) VBF Workshop, Fermilab, June 17 -19, 2009 7

Cut optimization Eye-balling on the most part? A little bit more automation? Relative importance of cuts? Andrey Korytov (UF) VBF Workshop, Fermilab, June 17 -19, 2009 8

Background = (? x ? + ? ) x ? Need to define the exact sequence of steps for defining background contributions: Background-by-background? n n n tt VV+jets Z+jets W+jets QCD for WW lvjj? Which factor is data-driven? MC-based? Judge systematic errors factor-by-factor… Andrey Korytov (UF) VBF Workshop, Fermilab, June 17 -19, 2009 9

Data driven methods A number of nice ideas Tt (from asking for n jets with a soft lepton) DY+jets (from Z+jets) VV+jets (relate to Z+jets? ) QCD (factorization of efficiencies with uncorrelated cuts? ) We certainly must follow them through, keeping in mind: event count in control samples at a given luminosity factorization may not always work (one needs to make a case for absence of correlations) ABCD does not necessarily work even if MC seems to work (one needs to make a case for absence of correlations) not every single thing should be “data-driven” Andrey Korytov (UF) VBF Workshop, Fermilab, June 17 -19, 2009 10

Lack of Monte Carlo samples VBF filters for MC production: to be checked for possible biases FAST sim: mostly not too bad wrt FULL (isolation is being fixed) good for validation of data-driven methods, factorization problems, etc. Creative: W(lv)+jets can serve as “Z(ll)”+jets Andrey Korytov (UF) VBF Workshop, Fermilab, June 17 -19, 2009 11

Many thanks To local organizers: Weimin, Haifeng, Dan To all contributors, speakers, participants We should have such gatherings more often than “once ever” so far Andrey Korytov (UF) VBF Workshop, Fermilab, June 17 -19, 2009 12