Micro BlackHoles rome

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Micro Black Holes: 

Micro Black Holes in the atlas detector Nick Brett and C. Issever University of Oxford ATLAS Physics Workshop - Rome - 08.06.2005

Black Holes At The LHC: 

Black Holes At The LHC 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 If Mpl ~ O(1 TeV)  Black Hole Production possible at LHC MBH = √S Parton Parton Rs = Schwarzschild radius N.Arkani-Hamed, S. Dimopoulos and G.R.Dvali [hep-ph/9803315] S.Dimopoulos and G. Landsberg [hep-ph/0106295] MBH~MPL: Study Quantum Gravity at the LHC

Black Hole Decay: 

Black Hole Decay Decay via Hawking Radiation Emit particles following an approximately black body thermal spectrum n = number of extra dimensions Astronomic BH -- COLD -- No Evaporation Micro BH -- HOT -- Evaporation Spectrum modified by Grey Body factors Black Hole might not maintain Thermal equilibrium

Black Hole Event in ATLAS: 

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 J. Tanaka, “Search for Black Holes”, 24th May 2003 at Athens High multiplicity events gamma Muon Decay of 6.1 TeV Black Hole

Black Hole Simulation: 

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 Aimed to extend atlfast results of JHEP05(2005)053 in full simulation Accounts for grey body factors Allows for temperature variation across black hole decay Includes recoil of black hole against decay products Charybdis Event Generator was Selected

Black Hole Simulation: 

Black Hole Simulation The following data sets have been produced with Charybdis Karina Flavia Loureiro and the Grid submission team have produced the following

Event Multiplicity (atlfast): 

Event Multiplicity (atlfast) High multiplicity events Multiplicity increases with MBH Multiplicity decreases with n

Event Multiplicity (atlfast): 

Event Multiplicity (atlfast) 5 TeV n = 2,4 and 6 sample 104 events each (atlfast)

Event Multiplicity: 

Event Multiplicity 6.0 – 6.5 TeV n = 2 sample Have applied the following cuts so far Electrons isEM & 0x7FF = 0 Et > 30GeV Delta eta < 0.01 Delta phi < 0.02 E/P(barrel) 0.8–1.3 E/P(endcap) 0.7–2.5 Photons No Cuts Muons Combined Muon Rec Jets Ehad/Eem > 0.2

Missing Et: 

Missing Et JHEP052005053 (atlfast) 6.0 – 6.5 TeV n=2 sample (full simulation) Background Missing Et Cut

Mass Reconstruction: 

Mass Reconstruction 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 Mass Reconstructed by summing 4-momenta of all decay products

Reconstructed BH Mass (atlfast): 

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?

Reconstructed BH Mass (full sim): 

Reconstructed BH Mass (full sim) Problems with double counting Improving Particle ID should reduce the problem A more robust method will be necessary Need to correct for detector acceptance and efficiencies 6.0 – 6.5 TeV n=2 sample

Temperature Reconstruction: 

Temperature Reconstruction Minimum of 4 jets PT of 3 leading jets > 500, 400 and 300 GeV respectively Missing PT < 100 GeV Electron η < 2.5 Electron ET > 30 GeV The following cuts were applied: Cuts taken from JHEP05(2005)053 Temperature reconstructed by fitting black body spectrum to electron energy distribution

Reconstructed Temperature: 

Reconstructed Temperature 5 – 14 TeV sample with n = 2 (atlfast) Problems Electrons are boosted by Black hole recoil Electrons are not all from the event horizon (secondaries) Theoretical uncertainties over Temperature variation during decay Alternative methods are proposed in JHEP 05(2005)053 Attempt to determine decay chain Use Leading decay product to sample a small section of the Black Body distribution

Slide16: 

Summary and Outlook Studied BH signals in ATLFAST Extended results of JHEP05(2005)053 in full simulation Problems with double counting Need more statistics in full simulation Must understand electron, muon, photon and jet collections Have made progress with electrons and jets Working with Karina Flavia Loureiro to understand event shape Aim to Reconstruct BH mass and Temperature Will explore temperature reconstruction methods outlined in JHEP05(2005)053 Plan to study backgrounds and systematics (inc. PDF uncertainty)