1 EDLHC Extra Dimensions the LHC Mge Karagz

1 ED@LHC Extra Dimensions @ the LHC Müge Karagöz Ünel MKU CERN 24 th Jan 2008 • Based on a talk given in 2007, so most ATLAS and Te. V results not updated. Sorry!

2 History Illustrated 1915 1925 ED@LHC 1687 MKU ~1960

3 Extra Dimensions • Not a new idea! MKU ED@LHC – Kaluza and Klein tried to unify electromagnetism and General Relativity in the ‘ 20 s by adding a 4 th spatial dimension • In late ‘ 90 s, models attempt to solve the hierarchy problem (MPl >> MEW) • A lot of variations since then… • Searches at current colliders boomed. .

4 “Modifying” Gravitational Law • Obtain size of the ED (compactification radius) from the gravitational potential (Gauss’ law) • • ED@LHC • • n=1 R~1013 cm: deviations of Newtonian gravity over solar distances; excluded. n=2 (R~ 100 m - 1 mm): within reach, ruled out by Eot-Wash table-top (<150 m) n>2, gravity modified at distances we can probe at colliders. Assume MPl(4+n) ~ m. EW, MKU MPl ~ 1019 Ge. V, MPl(4+n)~MEW

5 ED@LHC MKU Searches Concentrated on Large Extra Dimensions (LED, ADD): • n > 0 (n > 2), compactified, flat • Graviton in bulk • Could be as large as 0. 1 mm Te. V-1 ED (DDG): • n ≥ 1 (n = 1) • Gauge bosons in bulk as well Warped Extra Dimensions (RS): • n = 1, highly curved • 2 -branes solution: RS 1 • k/MPl, k: curvature, warp factor Universal Extra Dimensions (UED): • n = 1, flat, MUED: only 1 ED • KK-number conservation • All SM particles in the bulk • Lots of KK spectra Arkani-Hamed, Dimopoulos, Dvali Phys Lett B 429 (98) Dienes, Dudas, Gherghetta Nucl Phys B 537 (99) Randall, Sundrum Phys Rev Lett 83 (99) Appelquist, Cheng, Dobrescu Phys. Rev. D 64 (01)

ED@LHC 6 Bosonic KK modes: simpler signatures Large ED (ADD): ● Graviton in bulk ● DY interference, or missing E T Te. V-1 ED (DDG): ● Gauge Bosons and Higgs in bulk spin-1 KK resonances ● DY interference Warped ED (RS): ● Graviton resonances Virtual or resonance exchange ll ZZ qq MKU ● Universal ED (UED): ● spin-1 KK resonances emission jet+MET

7 ED@LHC Large Extra Dimensions (ADD) • Flat large EDs generate tower of KK gravitons with mass splitting ~ 1/RC continuum of graviton states • SM fields localized within 3 D-brane • Size of ED determined by the fundamental scale MD and # ED • n<=2 ruled out (by Eot-Wash) • MD < 1 Te. V ruled out by Tevatron Signatures: • Virtual production with DY interference excess above continuum • Real graviton emission with jet or photon Effective for continuum G MKU SM int s Hewett

8 MKU c>0. 1 forbidden Te. V Randall Sundrum (Type I) • Brane metric scales as function of bulk position • Coupling constant: c= k/MPl, k: curvature scale • Well separated narrow-width graviton mass spectrum with masses mn=kxnekrcπ (J 1(xn)=0) Planck ED@LHC Warped Extra Dimensions Bulk (y)

9 From Tevatron to LHC ED@LHC Most stringent limits to date from colliders: • CDF : k/MPl= 0. 1, m. G > 889 Ge. V (comb +ee) • D 0 : k/MPl = 0. 1, m. G > 865 Ge. V (di. EM) MKU • But we huge BSM reach increase from 2 Te. V to 14 Te. V!

10 Virtual Exchange Searches (LED) Signal ED@LHC SM Belotelov et al. , CMS PTDR 2006 Kabachenko et al. ATL-PHYS-2001 -012 • • • Di-photon/dilepton invariant mass Manageable backgrounds Min invariant mass cut extends reach MKU ATLAS Sensitivity for n=5. . 2 100 fb-1: MD ~6. 3 -7. 9 Te. V • 2 OS muons & Mμμ>1 Te. V • Bkgrd: mainly Irreducible DY • PYTHIA + CTEQ 6 L, Kf=1. 38 CMS 5 Sensitivity for n=6. . 3 • 1 fb-1: ~4. 0 -5. 5 Те. V • 100 fb-1: ~5. 5 -8. 2 Те. V

11 LED from Graviton Emission ED@LHC pp→jet+G • Signature: high ET jet + MET (from escaping G) • Bkgrnd: irreducible jet+Z/W via invisible decays ATLAS sensitivity in 100 fb-1 # ED, n 2 3 4 MD (Te. V) 9. 1 7. 0 6. 0 RC ( m) 8 - 10 -6 MKU pp→ + G • much lower rates than mono-jet signature • Signature: high-p. T photon + MET • Bkgrnd: irreducible Zγ → , and reducible fakes L. Vacavant, I. Hinchcliffe J. Phys G 27 (01) CMS sensitivity MD= 1– 1. 5 Te. V, n<7, 1 fb-1 2 - 2. 5 Te. V, n<7, 10 fb-1 3 - 3. 5 Te. V, n<6, 100 fb-1 CMS NOTE 2006/129 Rates for MD≥ 3. 5 Te. V are too low for 5σ discovery with systematics

12 WED RS 1 Searches ED@LHC ATLAS Spin exploitation • Use cosq* distribution of the dilepton system • Determine Spin-2 nature of graviton at 90% C. L. up to MG = 1720 Ge. V with 100 fb-1 CMS PTDR results • Use ll and : B(G-> ) = 2* B(G->ee/ ) • Reach in ee and similar (unmanageable bkgrnd) (also not enough stats) • CMS can detect at 5 up to 1. 8 Te. V (c=0. 01) and 3. 8 Te. V (c=0. 1) with 100 fb-1 • Uncertainties’ effect in mass ~150 Ge. V MKU M=1. 5, 1. 75, 2 Te. V No Kf for signal SM Allanach et al, hep-ph 0006114

13 ED@LHC Te. V-1 Searches in Dileptons • 1 ED with small enough compactification for gauge bosons to travel in bulk • All fermions localized at a fixed point (M 1) destructive interference with SM GB c. KK = √ 2 c. SM • q and l at opposite points (M 2) constructive interference • V(k) appear as resonances: Mk = √(M 02+k 2/R 2), k=1, 2, … • search for anomaly/bump in dilepton invariant mass pp Z(1 ) / (1) e+e. Azuelos, Polesello EPJ D C 39 Sup. 2 (04) MKU • ATLAS 5 reach in Mll (fast simulation): MC = 5. 8 Te. V in 100 fb-1 -If no peak, limit ~13 Te. V in 300 fb-1 • CMS 5 reach in Mee (full simulation): MC = 6. 0 Te. V in 80 fb-1 Z(1) can be discriminated from Z’ for up to ~5 Te. V with 300 fb-1 Clerbaux et al, 06

14 ED@LHC MKU Is it a Z’ or RS Graviton? J Aguilar Handles: • Mass little info about models (unless blessed enough to observe series of KK bumps) • Cross section info about couplings • BR test couplings & universality (G has well-defined ratio between ll/ /ZZ and Z’ has no coupling ) • Angular distribution/asymmetries spin and couplings (even then various Z’ are not easy to tell)

15 ATLAS W(1) Searches ED@LHC Te. V-1 searches in lepton+MET • Feasibility using fast simulation for • Search for a peak in MT(l ) • Analysis challenges: • – MET measurement, – for muons, the edge washed out. In 100 fb-1 – detect a peak, if MC(= R-1)<6 Te. V – fermionic couplings measured, if MC <~ 5 Te. V • If none observed, – use -ve interference with SM W (e only) MKU – a limit of MC < 11. 7 Te. V Polesello, Patra EPJ Direct C 32 Sup. 2 (04) V 4 Te V 6 Te

ED@LHC 16 Those -Blackholes • Arise from models with ED • Could be produced when ECM > MPl • Need QT of gravity as MBH approaches MPl • σ ~ πRS 2 ~ 1 Te. V-2 ~ 10 -38 m 2 ~ O(100)pb • LHC Black Hole Factory, rates as high as 1 Hz! MBH = √S Formation Parton Rs Parton Nick Brett MKU • If the impact parameter of a 2 -parton collision < Schwarzschild radius Rs, then a black hole with MBH is formed. Webber et al, 2005 BH from LED, possible from RS as well

17 -Blackhole Detection at ATLAS • BH lifetime ~ 10 -27 – 10 -25 seconds! • Decays with equal probability to all ED@LHC particles via Hawking Radiation (roughly a blackbody spectrum) • evaporates into (hadron : lepton)= (5 : 1) accounting for t, W, Z and H decays • Distinguishing features – High Multiplicity, ΣET, Sphericity, MPT – Democratic Decay • Theory estimates limit systematics • Charybdis event generator Giddings, Thomas PRD 65(2002)056010 Decay Harris, et al. JHEP 05 (2005) 053 6. 1 Te. V MBH MKU N=6 gives a larger yield than n=2 J. Tanaka , “Search for Black Holes”, 24/05/03 Athens “I have never won the national lottery, so go for it!” – anony, on BH threat from LHC!

18 Minimal Universal ED ED@LHC • • SM particles propagate in bulk with 1 ED KK-parity conservation – Leads to stable LKP as DM candidate – Pair of KK modes, no virtual KK modes Limits are weaker due to small cross sections 600 Q 1 570 Z 1 L 1 1 CMS g 1 g 1/G 1 Q 1/Q 1 Q 1 analysis: • 4 low-p. T isolated leptons (2 pairs of OS same flavour) l + m jets (m=4, 3, 2) + MET (from 2 undetected 1) • Irreducible background: tt + m jets, 4 b-jets, ZZ, Zbb • Discovery reach: MC ~600 Ge. V for 1 fb-1 MKU g 1 LEP + Te. Vatron limits: MC > 300 -400 Ge. V

19 Thick brane Universal ED • ED@LHC • • Thick brane solutions: One UED embedded in (SUSY) LED Gravity-matter interactions break PKK Pair of KK partons decaying to SM parton+graviton: g 1/g 1 ->q/g+G Measure excess of dijets with large MET Main backgrounds: dijets + Z/W decaying invisibly Signal BG MKK=1. 3 Te. V 200 MKU Beauchemin, Azuelos ATL-PHYS-PUB-2005 -003 600 1000 MET (Ge. V) 1400 Sensitivity: • if MC = 1. 3 Te. V, clear probing with 6 pb-1 • 5σ up to 2. 7 Te. V with 100 fb-1

20 Is it SUSY or UED? SUSY q MKU ED@LHC q~ Q 1 c~ 0 Z 21 UED ~ mm l 1 l ± c~g 110 (near ) l m (far ) Matchev UED decays are similar to SUSY: how to separate? • Look for 2 nd level KK modes (SUSY has none) - might be too heavy to observe • UED KK states are same spin of SM particles (SUSY are not) - use dilepton invariant mass - use asymmetry in lq mass • use q or qbar, near and far lepton invariant mass • Success of method SUSY point dependent • Expected to work at 100 -150 fb-1

21 RS with Custodial Symmetry • Favourite model building in warped space – Gauge hierarchy problem, unification – Fermion masses (localizations in the bulk) – Dark Matter candidate, “LZP”, CHAMP-like signatures ED@LHC • Ingredients of model building: – embed into SU(2)Lx. SU(2)Rx. U(1) (hep-ph/0612048) • Additional custodial symmetry in SU(2)Lx. SU(2)R to protect EW observables (Z→bb) – Light degenerate KK fermions (“custodians”) with no zero modes b. R, L, Q = 2/3, -1/3, 5/3 • Strategy: MKU – KK quarks searches and related signatures through multi-W events of b. R decays • Uncommon in SUSY searches • Stay as inclusive as possible – Multi-W events are generally interesting (WW scattering etc. . )

22 ED@LHC Production & Decay Signature: 4 W + 2 b-jets MKU • Strong interaction pair production dominates • Simulate t. W decay modes of b. R, Scale up for total rate • In 10 fb-1 of data 22 k t. W from q 5/3 at 500 Ge. V • Count Ws in hadronic decays • Overwhelming background: ttbar

23 ED@LHC MKU Conclusions • ED spectra is much wider now wrt a few years ago. • If ED exists at the Te. V scale, we will be able to observe inclusive signatures. • CMS and ATLAS reaches for KK resonances are similar. • With < 60 fb-1 LHC is expected to completely cover the RS 1 region of interest. • Many exclusive studies will be carried out with few fb-1 data… • Blackholes may be the “smoking gun” from early data as well as resonances.

24 ED@LHC MKU Flatland: A Romance of Many Dimensions With Illustrations by the Author, A SQUARE [Edwin Abbott] Dedication To The Inhabitants of SPACE IN GENERAL And H. C. IN PARTICULAR This Work is Dedicated By a Humble Native of Flatland In the Hope that Even as he was Initiated into the Mysteries Of THREE Dimensions Having been previously conversant With ONLY TWO So the Citizens of that Celestial Region May aspire yet higher and higher To the Secrets of FOUR FIVE OR EVEN SIX Dimensions Thereby contributing To the Enlargement of THE IMAGINATION And the possible Development Of that most and excellent Gift of MODESTY Among the Superior Races Of SOLID HUMANITY

MKU ED@LHC BACKUP 25

26 Tevatron: Other Signatures MKU ED@LHC RS Graviton resonance search • B(G→ZZ) = 0. 05 (x 2 B(G→ee)) • 4 very isolated electrons in ZZ • consistent with null observation at MG > 500 Ge. V • not yet sensitive for limits, need more luminosity LED Graviton emission search • Monojet + MET • Backgrounds: Z→ +jets, W→l +jets, QCD dijet. • Expected 819± 71, Observed 779. • LEP still better at low MD and n

27 ED@LHC MKU PP Motivations Ilustrated b mew

28 the Detectors ED@LHC 22 m 46 m MKU Tracker: /p. T 1. 5 10 -4 p. T 0. 005 EM Cal: /E 3%/ E(Ge. V) 0. 5% Hadron Cal: /E 100% / E(Ge. V) 5% Mu Spec: /p. T 5% at 1 Te. V/c (from Tracker) • Inner Tracking (| |<2. 5, 2 T solenoid) : • Silicon pixels and strips • Transition Radiation (e/ separation) • Calorimetry (| |<5) : • EM : Pb-LAr, Accordion shape • HAD: Fe/scintillator (centr), Cu/W-LAr (fwd) • Muon Spectrometer (| |<2. 7, 4 T toroid) : • air-core toroids with muon chambers • Tracking (| |<2. 5, 4 T solenoid) : • Silicon pixels and strips • Calorimetry (| |<5) : • EM : Pb. WO 4 crystals • HAD: brass/scintillator (centr+ end-cap), Fe/Quartz (fwd) • Muon Spectrometer (| |<2. 5) : • return yoke of solenoid with mu chambers

ED@LHC 29 How well do we know? The apparatus: C = 0. 01 • Detector effects need to be understood (coupling constant) • 5 discovery reach for RS gravitons in needs ~50% less data if alignment is optimal! First data C =0. 1 Long term (1 -5 fb-1) Dimuon Mass MKU The theory: • For LED, PDF uncertainties claimed to cancel reach above MC=4 Te. V • NLO corrections ~1. 6 S Ferrag Mc= 6 Te. V 2, 4, 6 ED

30 First Physics Run in 2008 How many events per experiment at the beginning ? l e or ED@LHC ~ 105 J/Psi + Y ll Assumed selection efficiency: W l , Z ll : 20% tt l +X : 1. 5% (no b-tag, inside mass bin) similar statistics to CDF, D 0 today + lots of min-bias and jets (107 events in 2 weeks of data taking if 20% of trigger bandwidth allocated) MKU 10 pb-1 1 month at 1030 and < 2 weeks at 1031, =50% -1 100 pb-1 few days 1 fb 6 month at 1032, =50% at 1032 , =50% • Large statistics of EW sample in a few weeks! 5 fb-1 3 month at 1032 and 3 month at 1033, =50% F. Gianotti, Ichep 06

MKU ED@LHC 31 RS ED & Z(n) Gokhan Unel, Athens 07

32 MKU ED@LHC Experimental Bounds on MD [Te. V] at 95% CL Karina F. Loureiro, C 2 CR 07