Inclusive analysis of supersymmetry in EGRET-point with one-lepton events: pp → 1ℓ + 4j + E Tmiss + Х V.A. Bednyakov, S.N. Karpov, E.V. Khramov and A.F. Pikelner, JINR, Dubna for the ATLAS collaboration Physics & Computing in ATLAS, 3 February 2010
EGRET region Restrictions on free parameters of mSUGRA were taken from: 1) Quantity of a dark matter in the Universe (measurements of the WMAP collaboration) 2) Breaking of electroweak symmetry on scale ~100 GeV 3) The limit on the Higgs boson mass m h >114 GeV 4) Surplus of the γ -ray flux observed by the EGRET collaboration is neutralino annihilation EGRET-point: m 0 = 1400 GeV, m 1/2 = 180 GeV, tanβ= 50, A 0 = 0, μ>0 [D.Yu. Bogachev, A.V. Gladyshev, D.I. Kazakov and A.S. Nechaev. Light superpartners at hadron colliders. // Int. J. of Mod. Phys. A, 2006, v.21, p.5221]
EGRET-point spectrum The minimal supergravity (mSUGRA) scenario with R-parity conservation was used in study of the SUSY signal. Mass spectrum of super-partner particles in EGRET-point was calculated with code ISASUGRA 7.78 at M top = 175 GeV, M 0 = 1400 GeV, M 1/2 = 180 GeV, tan(β)= 50, A 0 = 0, μ>0: ~u ~d ~s ~c ~b ~b(12) ~t ~t(12) L R ~e ~mu ~tau ~tau(12) ~nu_e ~nu_mu ~nu_tau L R ~g ~chi_10 ~chi_20 ~chi_30 ~chi_40 ~chi_1+ ~chi_ h0 H0 A0 H Dominant processes (~80%) in EGRET-point (11.6, 1.2 and 6.7 pb): The week-interacting supersymmetric particles are lightest in the spectrum
The pre-selection cuts for events with one isolated lepton and 4 jets (pp → 1ℓ + 4 jet + E Tmiss + X) 1.One isolated lepton with P T >20 GeV. There are no addition isolated leptons with 10< P T <20 GeV. 2.Not less than 4 jets with transverse momentum P T >50 GeV. Most energetic jet has P T >100 GeV. 3.Transverse missing energy E Tmiss >100 GeV. 4.Transverse missing energy relates to effective mass as E Tmiss >0.2∙M eff 5.Transverse sphericity S T >0.2 6.Transverse mass M T >100 GeV. 7.Effective mass M eff >800 GeV. The pre-selection cuts and SM background results were taken from studies of the ATLAS SUSY workgroup: [2] The ATLAS Collaboration, Expected Performance of the ATLAS Experiment, Detector, Trigger and Physics. CERN-OPEN , Geneva, [3] J. Abdallah et al., Prospects for SUSY discovery based on inclusive searches with the ATLAS detector at the LHC (Long Version). ATL-COM-PHYS , √s= 14 TeV, L= 1 fb –1
Distribution of transverse missing energy (E Tmiss ) after all cuts excepting 3 (E Tmiss > 100 GeV) √s= 14 TeV, L= 1 fb –1
Distribution of ratio of E Tmiss and M eff after all cuts excepting 4 (E Tmiss > 0.2∙M eff ) √s= 14 TeV, L= 1 fb –1
Distribution of transverse sphericity (S T ) after all cuts excepting 5 (S T > 0.2) √s= 14 TeV, L= 1 fb –1
Distribution of transverse mass (M T ) after all cuts excepting 6 (M T > 100 GeV) and 7 (M eff > 800 GeV) √s= 14 TeV, L= 1 fb –1
Distribution of effective mass (M eff ) for various SUSY-points and for SM background after cuts 1-6 √s= 14 TeV, L= 1 fb –1
The pre-selection cuts for events with one isolated lepton and 4 jets (pp → 1ℓ + 4 jet + E Tmiss + X) for √s= 10 TeV, L= 200 pb –1 1.One isolated lepton with P T > 20 GeV. There are no addition isolated leptons with 10 < P T < 20 GeV. 2.Not less than 4 jets with P T > 40 GeV. Most energetic jet have P T > 100 GeV. 3.Transverse missing energy E Tmiss > 80 GeV. 4.Transverse missing energy relates to effective mass as E Tmiss > 0.2∙M eff 5.Transverse sphericity S T > Transverse mass M T > 100 GeV. 7.Effective mass M eff > 800 GeV. The pre-selection cuts and SM background results were taken again from studies of the ATLAS SUSY workgroup: [4] The ATLAS Collaboration. Prospects for Supersymmetry and Universal Extra Dimensions discovery based on inclusive searches at a 10 TeV centre-of-mass energy with the ATLAS detector ATL-PHYS-PUB
Distribution of effective mass (M eff ) after cuts 1-6 (excepting cut: M eff > 800 GeV) √s= 10 TeV, L= 200 pb –1
Outlook 1.At the energy 14 TeV and L≈ 1 fb –1 there is a good chance for discovery supersymmetry with parameters in EGRET-point. 2.At the 10 TeV and L≈ 200 pb –1 one can hope to obtain only some indications (~3σ) that supersymmetry can exist in EGRET-point. 3.Further analysis with using Atlfast-II or Full Chain is needed. 4.Events with leptons and b-jets (1ℓ + 2bjet + X) and (2ℓ + 2bjet + X) should be analyzed for gluino pair production processes. 5.Events with two leptons (2ℓ + 3jet + X), (2ℓ + 2jet + X) and with three leptons (3ℓ + 1jet + X), (3ℓ + Øjet + E Tmiss + X) may be more preferable for EGRET-point analyses. 6.One lepton events with less number of jets (1ℓ + 3jet + X) and (1ℓ + 2jet + X) can be also used later. 7.An ATLAS-COMMUNICATIONS-NOTE is in preparation.
Backup
WMAP total dark matter limit < Ω CDM ·h 2 < (95% CL), [C.L. Bennett et al. ApJS, 148, 97, 2003/ D.N. Spergel et al. ApJS, 148, 175, 2003] 1. Bulk region (low m 0 and low m 1/2 ) 2. Stau-coannihilation region (moderate m 0, but large m 1/2 ) 3. Focus point region (large m 0 and low m 1/2 ) 4. A-annihilation funnel region (the region requires large tan β) 5. EGRET region (moderate m 0 and low m 1/2 ) tan β= 50, A= 0, μ>0 SU1, SU3, SU4 SU2 SU6 SU8
A.V. Gladyshev, “Supersymmery in Particle Physics”, Winter School, DIAS-TH, 26 January – 5 February 2008, JINR, Dubna, Russia EGRET Excess EGRET Data on diffuse Gamma Rays show excess in all sky directions with the same energy spectrum 9 yrs of data taken ( ) Main purpose: sky map of point sources above diffuse background The excess of diffuse gamma rays is compatible with WIMP mass of GeV Background WIMP
EGRET-samples (private production) Two private samples were generated at the EGRET-point with production of all available SUSY processes and with decays corresponding to EGRET-point branching: √s= 10 TeV, events per file, 10 files in all √s= 14 TeV, events per file, 10 files in all Number of events in each file conforms to statistics of SUSY events at the integrated luminosity 1 fb –1 (all 10 files: L≈ 10 fb –1 ) Monte Carlo generation was made in framework Athena rel with using of standard CSC-scripts: csc_evgen08_trf.py, Generation.JobTransformation.sh etc. Hard processes with creation of SUSY particles were generated with PYTHIA 6.4, electron-photon showers – with PHOTOS, tau- jets – with TAUOLA. The ATLAS detector simulation was made with the fast simulation pack Atlfast-I in framework Athena rel Output Ntuple files were analyzed with C++ codes in framework of mathematic-graphical tool ROOT.
Definition of M eff, M inv, M T and S T
Distribution of transverse missing energy (E Tmiss ) for various SUSY-points and for SM background after all cuts (1-7) √s= 14 TeV, L= 1 fb –1
Distribution of transverse mass (M T ) after cuts 1-5 (excepting cuts: M T > 100 GeV and M eff > 800 GeV) √s= 10 TeV, L= 200 pb –1
Main super-symmetric processes with direct production of chargino and neutralino pairs and their cascade decay 1. 2χ l + 2ν 3. 2χ l + ν5. 2χ l + ν + 2. 2χ 1 0 +l+ν+ 4. 2χ l + 3ν6. 2χ l +