Inclusive analysis of supersymmetry in EGRET-point

with one-lepton events: pp → 1ℓ + 4j + ETmiss + 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 mh>114 GeV

4) Surplus of the γ-ray flux observed by the EGRET collaboration is neutralino annihilation

EGRET-point: m0= 1400 GeV, m1/2= 180 GeV, tanβ= 50, A0= 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 Mtop= 175 GeV, M0= 1400 GeV, M1/2= 180 GeV, tan(β)= 50, A0= 0, μ>0:

~u ~d ~s ~c ~b ~b(12) ~t ~t(12)L 1435.73 1438.00 1438.00 1435.73 998.15 1010.41 998.15 863.51R 1438.29 1439.43 1439.43 1438.29 1128.15 1131.37 844.74 1029.14 ~e ~mu ~tau ~tau(12) ~nu_e ~nu_mu ~nu_tauL 1402.99 1402.99 1230.87 1031.80 1399.07 1399.07 1229.80R 1400.06 1400.06 1033.52 1234.02 ~g ~chi_10 ~chi_20 ~chi_30 ~chi_40 ~chi_1+ ~chi_2+ 517.72 68.50 125.19 225.14 254.04 125.73 253.39 h0 H0 A0 H+ 115.07 635.86 631.68 643.32

• Dominant processes (~80%) in EGRET-point (11.6, 1.2 and 6.7 pb):

The week-interacting supersymmetricparticles are lightest in the spectrum

;2~~*;2~~* 01

01 XjkngggqqXjknggggg

4,..1,0,,22*/* 014,3,2,1 knXjknWZqq

The pre-selection cuts for events with one isolated lepton and 4 jets (pp → 1ℓ + 4 jet + ETmiss + X)

1. One isolated lepton with PT >20 GeV. There are no addition isolated leptons with 10< PT <20 GeV.

2. Not less than 4 jets with transverse momentum PT >50 GeV. Most energetic jet has PT >100 GeV.

3. Transverse missing energy ETmiss >100 GeV.4. Transverse missing energy relates to effective mass as ETmiss>0.2 M∙ eff

5. Transverse sphericity ST >0.26. Transverse mass MT >100 GeV. 7. Effective mass Meff >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-2008-020, Geneva, 2008.

[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-2009-261, 2009.

√s= 14 TeV, L= 1 fb–1

Distribution of transverse missing energy (ETmiss) after all cuts excepting 3 (ETmiss > 100 GeV)

√s= 14 TeV, L= 1 fb–1

Distribution of ratio of ETmiss and Meff after all cuts excepting 4 (ETmiss > 0.2 M∙ eff)

√s= 14 TeV, L= 1 fb–1

Distribution of transverse sphericity (ST) after all cuts excepting 5 (ST > 0.2)

√s= 14 TeV, L= 1 fb–1

Distribution of transverse mass (MT) after all cuts excepting 6 (MT > 100 GeV) and 7 (Meff > 800 GeV)

√s= 14 TeV, L= 1 fb–1

Distribution of effective mass (Meff) 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 + ETmiss + X)

for √s= 10 TeV, L= 200 pb –1

1. One isolated lepton with PT > 20 GeV. There are no addition isolated leptons with 10 < PT < 20 GeV.

2. Not less than 4 jets with PT > 40 GeV. Most energetic jet have PT > 100 GeV.

3. Transverse missing energy ETmiss > 80 GeV.4. Transverse missing energy relates to effective mass as ETmiss > 0.2 M∙ eff

5. Transverse sphericity ST > 0.26. Transverse mass MT > 100 GeV. 7. Effective mass Meff > 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. 2009. ATL-PHYS-PUB-2009-084.

Distribution of effective mass (Meff) after cuts 1-6 (excepting cut: Meff > 800 GeV)

√s= 10 TeV, L= 200 pb –1

Outlook1. 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 + ETmiss + 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• 0.094 < ΩCDM·h2 < 0.129

(95% CL), [C.L. Bennett et al. ApJS, 148, 97, 2003/ D.N. Spergel et al. ApJS, 148, 175, 2003]

• 1. Bulk region (low m0 and low m1/2)

• 2. Stau-coannihilation region (moderate m0 , but large m1/2)

• 3. Focus point region (large m0 and low m1/2)

• 4. A-annihilation funnel region (the region requires large tan β)

• 5. EGRET region (moderate m0 and low m1/2)

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 (1991-2000) Main purpose: sky map of point sources above diffuse background

The excess of diffuse gamma rays is compatible with WIMP mass of 50 -100 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, 17600 events per file, 10 files in all√s= 14 TeV, 40700 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.14.2.10 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.15.2.0.

• Output Ntuple files were analyzed with C++ codes in framework of mathematic-graphical tool ROOT.

Definition of Meff , Minv , MT and ST

eptonsjets and lallkyandxarejiwhere

,ppS tensorsphericity momentum

of the genvalues are the eiS

ppEEorM

ppEEmm

PPorM

EPPM

k

kjkiij

T

TmissTTmissTT

missmiss

inv

TmissTi

ijetTeff

;,

,,

;

/

/

,

22

2

2

2

2121

2

22

2

442

4

1

Distribution of transverse missing energy (ETmiss) for various SUSY-points and for SM background after all cuts (1-7)

√s= 14 TeV, L= 1 fb–1

Distribution of transverse mass (MT) after cuts 1-5 (excepting cuts: MT > 100 GeV and Meff > 800 GeV)

√s= 10 TeV, L= 200 pb –1

Main super-symmetric processes with direct production of chargino and neutralino pairs

and their cascade decay1. 2χ1

0 + 2l + 2νqq 3. 2χ10 + 3l + ν'qq 5. 2χ1

0 + l + ν +'qq qq

2. 2χ10+l+ν+qq qq 4. 2χ1

0 + l + 3ν'qq 6. 2χ10 + 2l + 'qq qq