Overview of Extra Dimension studies at LHC Vladimir Litvin, Caltech, CMS

Outline CMS studies –RS-1 graviton di-electron decay study (2005) –RS-1 graviton di-photon decay study (2006) –Radion decay study (2005) ATLAS studies –Large extra dimension (2001) –Randall-Sundrum graviton (2001) –KK boson study (2001)

D0 results on Search for Randall-Sundrum Gravitons in Dilepton and Diphoton Final State hep-ex/ May 2005 RS-1 Graviton masses up to 785 (250) GeV for c = 0.01 (0.1)

RS-1 graviton cross-sections and lorentzian widths RS-1 graviton cross-sections (left) and lorentzian widths (right). Square markers for the cross-sections are for qq production, triangle markers are for gg and circles are for the total cross-section

RS graviton di-electron study C. Collard, M-C.Lemaire, Eur. Phys. J. C40 (2005), Num 5, 15

RS graviton di-electron study A graviton resonance with a mass of 900 GeV (left) and 1.1 TeV (right) and a coupling parameter c=0.01 is displayed above the Drell- Yan background for an integrated luminosity of 10 fb -1

RS graviton di-electron study The figures present the expected signal above the Drell-Yan background for an integrated luminosity of 100 fb -1, for different mass hypotheses (M=1.5, 1.75 and 2 TeV) and c=0.01

RS graviton di-electron study Significance is plotted as a function of the mass for different integrated luminosities (from 1 to 100 fb -1 ) for c =0.01 (left) and c=0.1 (right). With 100 fb -1, CMS will be able to detect a graviton resonance at 5 sigma up to 1.8 TeV for c=0.01 and 3.8 TeV for c=0.1

RS graviton di-electron study The figure presents the reach for CMS in the (M G,c) plane for different integrated luminosities (from 1 to 100 fb -1 ), based on full simulation and reconstruction of CMS. The region of interest comes from theoretical constraints on the coupling parameter c and the mass M G of the first Kaluza-Klein excitation of graviton. With an integrated luminosity of 100 fb -1, CMS will cover the whole region of interest. Note that for the Drell-Yan background a K factor of 1.3 is taken into account but no K factor is used for the signal

RS graviton di-electron study We presented preliminary results on the discovery potential for RS-1 graviton in the di- electron decay mode. Confidence Limits for 30 fb -1 c=0.01 M G = 1.41 TeV c=0.1 M G = 3.25 TeV Confidence Limits for 10 fb -1 c=0.01 M G = 1.21 TeV c=0.1 M G = 2.87 TeV

RS-1 graviton di-photon study M.-C. Lemaire, V.Litvin, H.Newman, CMS Analysis Note 2005/032

Requested Datasets We have used next datasets for analysis: –Signal (see plot on the next slide) –c=0.01 M=1.0, 1.25, 1.5, 1.75, 2.0, 2.25, 2.5 TeV/c 2 1k each –c=0.02 M=1.0, 1.5, 2.0, 2.5, 3.0 TeV/c 2 1k each –c=0.05 M=1.0, 1.5, 2.0, 2.5, 3.0, 3.5 TeV/c 2 1k each –c=0.075 M=2.5, 3.0, 3.5, 4.0 TeV/c 2 1k each –c=0.1 M=1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5 TeV/c 2 1k each –There are five backgrounds we need to study: –born (MSEL = 0, MSUB = 18) –box (MSEL = 0, MSUB = 114) –brem (MSEL = 0, MSUB = 14,29,115) –QCD (MSEL = 1) –DY (MSEL = 0, MSUB = 1, MSTP 43 = 3). We are using PHOTOS radiation for Z boson decay - MSTJ 41 = 1 was added.

Discovery plane for RS-1 graviton

RS-1 graviton cross-sections and lorentzian widths RS-1 graviton cross-sections (left) and lorentzian widths (right). Square markers for the cross-sections are for qq production, triangle markers are for gg and circles are for the total cross-section

Signal + backgrounds vs invariant mass: 30 fb -1

Signal + backgrounds vs invariant mass: 10 fb -1

Significance c=0.01 for L=30 fb -1 Born k=1.5 Box k=1.2 with M G = 1.0 TeV/c 2 M G =1.25 TeV/c 2 M G = 1.5 TeV/c 2 M G =1.75 TeV/c 2 M G = 2.0 TeV/c 2 NsNs N bkg S

Significance c=0.1 for L= 30 fb -1 Born k=1.5 Box k=1.2 with M G = 2.5 TeV/c 2 M G =3.0 TeV/c 2 M G = 3.5 TeV/c 2 M G =4.0 TeV/c 2 M G = 4.5 TeV/c 2 NsNs N bkg S

Significance vs RS-1 graviton invariant mass Significance plots are not taking systematic errors into account

Discovery potential

Electron and photon discovery potential

Limits Uncertainties for 30fb -1 Hard scale uncertainties LHApdf uncertainties –c= GeV/c 2 –c= GeV/c 2 Preselection uncertainty was calculated based on 2% (QCD) and 1% (brem) upper limit of inefficiencies. It propagates to 1-2% cross-section uncertainties and uncertainty in the number of background events –c= GeV/c 2 –c= GeV/c 2 Uncertainty due to the fact, that Tevatron has a K- factor =2 for born instead of 1.5 ( D. Acosta et al., CDF Collaboration, PRL 95(2005) ) as we have here –c= GeV/c 2 –c= GeV/c 2 4s0.25s C= GeV/c GeV/c 2 C= GeV/c GeV/c 2

Conclusion We presented preliminary results on the discovery potential for RS-1 graviton in the diphoton decay mode. Various confidence limits systematic uncertainties have been estimated – hard process scale, LHApdf uncertainties for the signal as well as for the background. They are changing the results from 50 to 150 GeV. Confidence Limits for 30 fb -1 c=0.01 M G = 1.61 TeV c=0.1 M G = 3.95 TeV Confidence Limits for 10 fb -1 c=0.01 M G = 1.31 TeV c=0.1 M G = 3.47 TeV

CMS Radion study (gg->radion->hh->2  +2b ) Left plot :  b j invariant mass for the irreducible background and the signal plus background after all selections with 30 fb -1. Signal was evaluated for the maximal cross section times branching ratios point in the mixing-scale parameter plane. Right plot :  b j invariant mass for the irreducible background and the signal plus background after all selections with 30 fb -1. Signal plus background distribution is shown for the point in mixing-scale parameter plane where statistical significance 5 is obtained. Dashed histograms correspond to the irreducible background calculated with the renormalization and factorization scales set to 0.5 M Z and 2 M Z D. Dominici, G. Dewhirst, S. Gennai, L. Fano', A. Nikitenko, CMS Note 2005/007

CMS Radion study (gg->radion->hh->2  +2b ) The 5 sigma discovery contours for gg->radion->hh->2gamma+2b channel with 30 fb -1. Left plot: only irreducible background was taken into account. Central plot : total background was taken into account assuming that the ratio of the reducible to the total background is 0.4 (from the preliminary full simulation of the total background for the inclusive h->  study). Right plot: solid (dashed) line contour present the discovery reach without (with) systematical error on the background (of 4.7 %) and for the total background evaluated as described above. D. Dominici, G. Dewhirst, S. Gennai, L. Fano', A. Nikitenko, CMS Note 2005/007

CMS Radion study (gg->radion->hh->2  +2b ) The 5 sigma discovery contours with 30 fb -1 when NLO background cross sections were taken at maximal and minimal values corresponding to the scale variation and PDF uncertainties. Left plot : stat. error only is taken into account. Right plot: stat. errors and 5 % of the syst. uncertainty on the background are taken into account. D. Dominici, G. Dewhirst, S. Gennai, L. Fano', A. Nikitenko, CMS Note 2005/007

CMS Radion study (gg->radion->hh->4b ) b b j j invariant mass for the signal and background after all selections with 30 fb -1. NLO cross sections for the signal and LO for the background were used. Fast simulation for the signal and background. Background can be normalized in the signal free region of the four-jet invariant mass (assuming that radion mass will be known from the other channels) and extrapolated then to the region of the signal. To have 5 sigma discovery at the maximal cross section times branching ratios point in mixing-scale plane the uncertainty of the extrapolation should be less than 0.1 %. D. Dominici, G. Dewhirst, S. Gennai, L. Fano', A. Nikitenko, CMS Note 2005/007

ATLAS ATLAS studies –Large extra dimension (2001) –Randall-Sundrum graviton (2001) –KK boson study (2001)

ATLAS Large extra dimension, jet + E Tmiss (ISAJET +AtlFast) Signal: direct Graviton + 1 jet production Main background: jet + Z(W) [Z ,W  l ] L.Vacavant, I. Hinchliffe (J. Phys. G: Nucl. Part. Phys. 27 (2001) )

ATLAS Large extra dimension, di-photon and di-lepton decays Kabachenko, Miagkov, Zenin (ATL-PHYS ) pp   +X pp  l + + l - - +X All channels combined: 10 fb fb -1

ATLAS Randall-Sundrum graviton di-electron decay study (1) B.C. Allanach, K. Odagiri, M.A. Parker, B.R. Weber (JHEP 09 (2000) 019 – ATL-PHYS ) gg (qq)  G  e + e -

ATLAS Randall-Sundrum graviton di-electron decay study (2) gg (qq)  G  e + e - B.C. Allanach, K. Odagiri, M.A. Parker, B.R. Weber (JHEP 09 (2000) 019 – ATL-PHYS ) HELAS has been modified to work with spin-2 particles

ATLAS Radion studies G.Azuelos,D.Cavalli,L.Vacavant,H.Przysiezniak (Les Houches Workshop 2001 Proc.) 100fb -1,  = 0,   = 1(10) TeV    S/  B~10(.1) for 80<m  <160 GeV/c 2   ZZ (*) S/  B~100(1) for 200<m  <600 GeV/c 2  ->hh->bb    max =4.6 TeV for m  = 300 GeV/c 2 and   max =5.7 TeV for m  = 600 GeV/c 2  ->hh->bb  Require a minimum of 10 evts and S/  B  5:   max =1.05 TeV for m  = 300 GeV/c 2 et   max =1.4 TeV for m  = 600 GeV/c 2

ATLAS Scenario TeV -1 (Search for KK boson decay, through  and Z, in e + e - and  +  - channels) Search for KK boson decays through g and Z, pp  e + e - +X or pp  µ + µ - +X Cuts: –M ll >1 TeV –Pt l > 20 GeV and |h|<2.5 For 100 fb -1, M c ~5.8 TeV – s>5, N>10 G. Azuelos, G. Polesello, EPJ Direct C (2004) /epjcd/s y

ATLAS Scenario TeV -1 (Search for KK boson decay, through  and Z, with W ) Search for KK boson decay, through g and Z, with W pp  e +/- +X or pp  µ + +X (W 1  l +/- ) Backgrounds: tt (semi-leptonic), WW, ZZ, WZ Cuts : –1 isolated lepton (E<10 GeV, DR=0.2) –Pt l > 200 Gev and |h|<2.5 –Pt miss > 200 GeV –Mt ln > 1000 GeV G. Polesello, M. Prata, EPJ Direct, C: 32 Sup.2 (2004) pp.55-67