1. Leonid G. Levchuk -- 8th Annual CMS/RDMS Meeting, Dubna, Russia KIPT On the possibility to observe with CMS a moderately heavy Higgs decaying via H  ZZ  ll Leonid G. Levchuk Kharkov Institute of Physics & Technology

2. 2 Leonid G.Levchuk – 8 th Annual CMS/RDMS Meeting, Dubna, Russia 05 Dec 2003KIPT Motivation  Search for physics suggesting importance of hadron calorimetry  H  ZZ  ll has ~6 times greater BR compared to H  ZZ  4l  Some light could be shed on physics of ZZ interaction

3. 3 Leonid G.Levchuk – 8 th Annual CMS/RDMS Meeting, Dubna, Russia 05 Dec 2003KIPT Previous studies  N.Stepanov, CMS-TN/93-087 (1993); N.Stepanov and S.Abdullin, CMS-TN/94-178 (1994); I.Gaines, D.Green, S.Kunori, J.Marrafino, J.Womersley, and W.Wu, CMS-TN/95-84 (1995)  heavy (M H >500 GeV) Higgs observability via H  ZZ  ll was studied; irreducible background (IB) due to ZZ/ZW production thwarts H observation  L.Levchuk, 6 th annual RDMS CMS collaboration meeting (MSU, Moscow, 2001); L.Levchuk, D.Soroka, P.Sorokin, V.Trubnikov, and S.Zub, 7 th annual RDMS CMS collaboration meeting (IHEP, Protvino, 2002)  extension to M H =200  250 GeV; ways to eliminate IB

4. 4 Leonid G.Levchuk – 8 th Annual CMS/RDMS Meeting, Dubna, Russia 05 Dec 2003KIPT Simulation tools u PYTHIA (Ver. 6.158) u CMSJET (Ver. 4.703)   Z+jets     ZZ   ZW Background contributions irreducible background

5. 5 Leonid G.Levchuk – 8 th Annual CMS/RDMS Meeting, Dubna, Russia 05 Dec 2003KIPT 1-st level (“tentative”) cuts: E T miss > 60 GeV, 2 leptons such that : |  l | 20 GeV, P T ll > 40 GeV, |M Z -M ll | < 5 GeV At threshold of decay, At threshold of H  ZZ decay, (M T ZZ  2M Z ) 1/2  | | At threshold of decay, At threshold of H  ZZ decay, (M T ZZ  2M Z ) 1/2  | |

6. 6 Leonid G.Levchuk – 8 th Annual CMS/RDMS Meeting, Dubna, Russia 05 Dec 2003KIPT

7. 7 Leonid G.Levchuk – 8 th Annual CMS/RDMS Meeting, Dubna, Russia 05 Dec 2003KIPT

8. 8 Leonid G.Levchuk – 8 th Annual CMS/RDMS Meeting, Dubna, Russia 05 Dec 2003KIPT “Loose” cuts (“A”) 1-st level (“tentative”) cuts: E T miss > 60 GeV, 2 leptons such that : |  l | 20 GeV, P T ll > 40 GeV, |M Z -M ll | < 5 GeV Elimination of the IB: No b-jets: N b-jets =0

9. 9 Leonid G.Levchuk – 8 th Annual CMS/RDMS Meeting, Dubna, Russia 05 Dec 2003KIPT

10. 10 Leonid G.Levchuk – 8 th Annual CMS/RDMS Meeting, Dubna, Russia 05 Dec 2003KIPT “Hard” cuts (“C”) 1-st level (“tentative”) cuts with loosed cut on E T miss : E T miss > 40 GeV, 2 leptons such that : |  l | 20 GeV, P T ll > 40 GeV, |M Z -M ll | < 5 GeV Elimination of the IB: No b-jets: N b-jets =0 Extra criteria (I): Extra criterion (II) – selection of single-jet events: N j =1, 1.0 40 GeV

11. 11 Leonid G.Levchuk – 8 th Annual CMS/RDMS Meeting, Dubna, Russia 05 Dec 2003KIPT

12. 12 Leonid G.Levchuk – 8 th Annual CMS/RDMS Meeting, Dubna, Russia 05 Dec 2003KIPT

13. 13 Leonid G.Levchuk – 8 th Annual CMS/RDMS Meeting, Dubna, Russia 05 Dec 2003KIPT

14. 14 Leonid G.Levchuk – 8 th Annual CMS/RDMS Meeting, Dubna, Russia 05 Dec 2003KIPT Current status and plans for nearest future u Publication of the preliminary results  L.G.Levchuk, P.V.Sorokin and S.Kunori, “On the possibility to observe a heavy Higgs via H  ZZ  ll decays at CMS”, CMS Note (or CMS_IN?) – in preparation u Search with “fast” MC for kinematical criteria providing a better signal/background ratio  In case of success, preparation for “detailed” (OSCAR or CMSIM) simulation & ORCA reconstruction u Check for reliability and degree of the IB suppression  Simulations with a generator other than PYTHIA (HERWIG, …?)  Simulations of the non-resonant ZZ/ZW production accompanied by high-p T jets based on 2  3 hard processes (COMPHEP, …?)  NLO calculations of the non-resonant ZZ/ZW production (MC@NLO_2.2 [http://www.hep.phy.cam.ac.uk/theory/webber/MCatNLO], …? ) u Consideration of the 2  3 Higgs production  A generator for a combined treatment for both WBF and QCD 2  3 mechanisms of Higgs production – under development