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Micro Black Holes. in the atlas detector. Nick Brett and C. Issever University of Oxford. UK ATLAS Exotics and SUSY Group Meeting - 11.07.2005. R s. Black Holes At The LHC. If M pl ~ O(1 TeV) Black Hole Production possible at LHC.
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Micro Black Holes in the atlas detector Nick Brett and C. Issever University of Oxford UK ATLAS Exotics and SUSY Group Meeting - 11.07.2005
Rs Black Holes At The LHC If Mpl ~ O(1 TeV) Black Hole Production possible at LHC N.Arkani-Hamed, S. Dimopoulos and G.R.Dvali [hep-ph/9803315] S.Dimopoulos and G. Landsberg [hep-ph/0106295] σ ~ πRS2 ~ O(100)pb LHC Black Hole Factory BH lifetime ~ 10-27 – 10-25 seconds Decays with equal probability to all particles via Hawking Radiation MBH = √S Parton Parton MBH~MPL: Study Quantum Gravity at the LHC Rs = Schwarzschild radius Nick Brett - University of Oxford
Black Hole Decay • Decay via Hawking Radiation • Emit particles following an approximately black body thermal spectrum n = number of extra dimensions Spectrum modified by Grey Body factors Black Hole might not maintain Thermal equilibrium Astronomic BH -- COLD -- No Evaporation Micro BH -- HOT -- Evaporation Nick Brett - University of Oxford
Black Hole Event in ATLAS BH evaporates into (q and g : leptons : Z and W : n and G : H) = (72%:11%:8%:6%:2%:1%) (hadron : lepton) is (5 : 1) accounting for t, W, Z and H decays S.B. Giddings, S. Thomas, Phys.Rev.D65(2002)056010 gamma Decay of 6.1 TeV Black Hole High multiplicity events Muon J. Tanaka, “Search for Black Holes”, 24th May 2003 at Athens Nick Brett - University of Oxford
Black Hole Simulation Study of Black Holes with the ATLAS detector at the LHC (J.Tanaka, T.Yamamura, S.Asai,J.Kanzaki) ATL-PHYS-2003-037 Black Holes at Future Colliders and Beyond (G.Landsberg) HEP-PH/0205174 CHARYBDIS: A Black Hole Event Generator (C.M. Harris, P.Richardson and B.R. Webber) CERN-TH / 2003-170 Exploring higher dimensional black holes at the Large Hadron Collider (C.M. Harris, M.J.Palmer, M.A.Parker, P.Richardson, A.Sabetfakhri, B.R.Webber) JHEP05(2005)053 Charybdis Event Generator was Selected Accounts for grey body factors Allows for temperature variation across black hole decay Includes recoil of black hole against decay products Aimed to extend atlfast results of JHEP05(2005)053 in full simulation Nick Brett - University of Oxford
Aims of Analysis • Black Hole Mass Measurement • Interesting Physical Quantity • Requirement for further study i.e. Temperature measurement • Black Hole Cross Section Measurement • Developing ID cuts • Trigger Efficiencies Nick Brett - University of Oxford
Mass Reconstruction Mass Reconstructed by summing 4-momenta of all decay products • Minimum of 4 jets • PT of 3 leading jets > 500, 400, 300 GeV respectively • Missing ET < 100 GeV • Eta < 2.5 The following cuts were applied: Cuts taken from JHEP05(2005)053 Nick Brett - University of Oxford
Reconstructed BH Mass (atlfast) BH will be produced with a range of masses at LHC Mass reconstruction by Σ P of all decay products Mass Resolution ? Offset due to detector acceptance and energy scale? Nick Brett - University of Oxford
Reconstructed BH Mass (full sim) 6.0 – 6.5 TeV n=2 sample • Problems with double counting • Improving Particle ID should reduce the problem • A more robust method will be necessary Nick Brett - University of Oxford
Run Reconstruction Algorithms Independently Compare momentum of Reconstructed Particles Exclude those who’s momentum is within the same cone as another Overlap ( Delta R ) 6.0 – 6.5 TeV n=2 sample Nick Brett - University of Oxford
Overlap ( EventView ) • Provides a Common Base for Overlap Solutions • Currently Uses a DeltaR Algorithm ( With Additional Parameters ) • Allows for development of more complex filters https://uimon.cern.ch/twiki/bin/view/Atlas/EventView 6.0 – 6.5 TeV n=2 sample Nick Brett - University of Oxford
Energy Scales 6.0 – 6.5 TeV n=2 sample Decay Products Have Very High Energy Need To Understand Energy/Momentum Reconstruction in this region Plan To Work With Electrons Nick Brett - University of Oxford
Cross Section Measurement Aim To Develop Selection Cuts and Determine Their Efficiencies Nick Brett - University of Oxford
Event Shape Variables Sphericity Thrust 6.0 – 6.5 TeV n=2 sample Nick Brett - University of Oxford
Summary and Outlook • Mass Reconstruction • Must Solve Overlap Problem Appropriately for Black Holes • Study Energy Scales For Very High Pt Objects • Will investigate Electrons between 500 - 1500 GeV • Possibly move onto Photons • No plans to study Muons and Jets ( due to time constraints) • Cross Section Measurement • Need To Develop Selection Cuts • Event shape variables may be useful • Must Acquire Appropriate backgrounds • t-tbar, qcd Nick Brett - University of Oxford