Trilepton+top signal from chargino-neutralino decays of MSSM charged Higgs bosons 12 Nov 2004, 10 th Nordic LHC Physics Workshop, Stockholm Christian Hansen Uppsala University Nils Gollub Uppsala University Ketevi Assamagan BNL Tord Ekelöf Uppsala University Bjarte Mohn Bergen University

Introduction Not possible to cover low tanβ region with SM decays → Try susy decays Discovery Potentials for H + (from 2→2 processes) when H + → SM particles

Introduction (cont) The channel with where N = invisible final state particles and with has been studied with CMSJET. M. Bisset, F. Moortgat and S. Moretti, “Trilepton+top signal from chargino-neutralino decays of MSSM charged Higgs bosons at the LHC”, hep-ph/ v2 1 Oct 2003

Introduction (cont) CMS’ result : Parameter Set A : M 2 = 210 GeV μ = 135 GeV m l̃R = 110 GeV m g ̃ = 800 GeV m q = 1 TeV where soft slepton and squark masses are degenerate for all generations, where m l̃R = m l̃L and where M 1 = 3/5tan 2 θ W M 2 hep-ph/ v2 1 Oct 2003 Our aim is to perform a similar study using ATLFAST

Event Production Used HERWIG for event production and ATLFAST for fast detector simulation Have results for, tanβ = 10, 20, 30, 40 and m A = 200, 250, 300, 350, 400, 450, 500 GeV, in the Parameter Set A ProcessNumber Events Produced gb → H + t, H + → χχ → 3l+N and t → bqq  4·10 5 for each (tanβ, m A ) gb → tt10 8 gb → ttZ2·10 7 gb → tth10 7 for each (tanβ, m A ) gb → χχ10 7 for each (tanβ, m A ) gb → q, g  10 6 for each (tanβ, m A ) Signal SM Bkg SUSY Bkg

Signal CS ; NLO from Bkg CS ; from Herwig CS(tt) = fb CS(ttZ) = fb Cross Section Tilman Plehn, “Charged Higgs boson production in bottom- gluon fusion”, PHYSICAL REVIEW D 67, (2003)

Signal Branching Ratio: H + is forced to decay to χχ which are forced to decay to 3 leptons and a number N of undetectable particles The top is forced to decay hadronically, e.g. for tanβ = 20, m A = 350 BR TOT = BR(H + → χχ →3l+N)*BR(t→bqq) = 0.26*2/3 = 0.18 Luminosity: 100 fb -1 assumed Signal Branching Ratio

The Signal

Examples of H + → 3l+N

Cuts: 3 Lepton Cut Events must have exactly three isolated leptons (e or μ) with p T > 20, 7, 7 GeV, all with |η| < 2.4

Cuts: 2l Mass Cut The invariant mass of the two same flavor, opposite sign leptons have to be less than 63 GeV χ 0 j → 2 same flavor, opposite sign leptons + one (or more if j>2) undetectable particle(s) Out of the three isolated leptons at least 2 are required to have same flavor and opposite sign The inv. mass of these two is kinematically constrained. For j=2: If third lepton has same flavor, the biggest M ll are used for the cut 10 < M ll < 63

Cuts: 2l Mass Cut The invariant mass of the two same flavor, opposite sign leptons have to be less than 63 GeV Signal events, gb → H + t j = 2 j = 3

Cuts: 2l Mass Cut The invariant mass of the two same flavor, opposite sign leptons have to be less than 63 GeV Bkg, gb → tt

Cuts: 2l Mass Cut The invariant mass of the two same flavor, opposite sign leptons have to be less than 63 GeV

Cuts: Top Cut Must have at least three jets with p T > 20 GeV in |η| < 4.5 Among these select 3 top jets by min( |m jjj – m t | ) < 35 GeV Among these select 2 W jets by min( |m jj – M W | ) < 15 GeV

Cuts: Jet Cut Reject if the p T sum of the non top jets with p T > 50 GeV extends 500 GeV

Sigma Scan

Future Work When enough significance results on the tanβ vs. m A plane is achieved, make a 5σ discovery potential contour Make 5σ scans for different Parameter Sets Contour Other Sets Background Include one more background channel; ttγ * More Events SweGrid is constantly (but very instable) producing Signal and Bkg events for various tanβ, m A values Independence Investigate if the susy backgrounds could be independent of tanβ or m A Would save lots of CPU time