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Resonance Signatures (mostly Drell-Yan)

Resonance Signatures (mostly Drell-Yan). G. Azuelos (ATLAS Collaboration) U. Montréal/TRIUMF. Z’-like di-lepton resonances, weak and strong predicted by numerous models: extended gauge, technicolor, extra dimensions, Little Higgs, BESS, W’-like resonances.

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Resonance Signatures (mostly Drell-Yan)

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  1. Resonance Signatures(mostly Drell-Yan) G. Azuelos (ATLAS Collaboration) U. Montréal/TRIUMF • Z’-like di-lepton resonances, weak and strong • predicted by numerous models: • extended gauge, technicolor, extra dimensions, Little Higgs, BESS, • W’-like resonances an experimental perspective

  2. Resonances: the source of BSM physics discovery • Theoretical guidance: • what is most interesting • what motivates future collider • Experimental approach: • generic, model-independent • 2-body resonance from any 2 objects possibly described by some theoretical model • Here, will focus on potential early discoveries • leptonic resonances at LHC • top-pair • exclude: • LQ (potential for early LHC results) • 4th family quarks (see talks by E. Kou and S. Sultansoy) • gauge boson resonances (see talk by E. Ozcan) • Higgs, SUSY partners, ... Basic references: - ATLAS CSC notes, arXiv:0901.0512 - CMS, CERN/LHCC 2006-021 - M. Battaglia et al, Physics at CLIC, hep-ph/0412225 - G. Weiglen et al., LHC/ILC interplay, hep-ph/0410364 G. Azuelos - LHC2FC

  3. Z’-like resonances • Extended gauge group? SU(2)LxU(1)Y unnatural? • SU(5), E6, …? • Z’, W’, heavy fermions, Leptoquarks, extended Higgs sector,… • Little Higgs model • 3-3-1 • Extra Dimensions? • Graviton KK resonances • ADD → continuum • RS → narrow resonances • Gauge boson KK resonances • Gauge-Higgs unification, Higgsless models, • fermiophobic Z’ • with bulk localization: flavor-dependent couplings • fermion KK resonances, in particular g*KK • UED • Dynamical EWSB (see WG1 and WG2) • Technicolor • DBESS, • … • more exotic • unparticles, … G. Azuelos - LHC2FC

  4. Z’ resonances: potential early LHC physics Leptonic resonances should be relatively easy and quick to discover, but: • what are they?, in what model do they fit? what are the couplings to fermions and bosons? • what can we measure, and with what precision? • production cross section and decay branching ratios • width • interferences (and interference with Drell-Yan for Z’) • FB asymmetry • rapidity distribution • associated with what other new physics? LHC: a discovery machine ILC: precision measurements SLHC: ultimate (?) window into the unknown mu-collider: new possibilities G. Azuelos - LHC2FC

  5. SSM: Z’ couplings same as those of Z • width ~ 3% of mass, for SSM Z’ • could increase if or if • very little background parton level ~ 2 fb-1 for SSM Z’ Events per 20 GeV Z’ resonance discovery at the LHC - present limits ~ 600 GeV if SM couplings  not interesting for 500 GeV ILC, unless couplings are lower than SM - mixing Z-Z’ < 10-3 from LEP EW measurements • relatively clean signal • NLO uncertainties • need good determination of efficiencies, resolution, energy scale (in situ calibration?), charge determination, jet rejection… • luminosity • more difficult to measure DY continuum with precision Langacker, arXiv:0801.1345 Statistics not a problem: ILC helps with precision or investigation of some rare couplings G. Azuelos - LHC2FC

  6. Z’ → mm CMS, CERN/LHCC 2006-021 0.1 fb-1 0.1 fb-1with early misalignment Z’ in very early data Z’ → ee ATLAS, 0.1 fb-1 with misalignments G. Azuelos - LHC2FC

  7. Observables at the LHC resonance shape Z’ rapidity Julien Morel, PhD Thesis ATLAS ang. dist’n at peak FB asymmetry model sensitivity:M Dittmar, A Djouadi, A-S Nicollerat, Phys.Lett. B583 (2004) 111 G. Azuelos - LHC2FC

  8. AFB at the LHC AFB and angular distributions • In a pp collider, we must resort to “guess” that Z’ boost is in direction of quark (by opposition to antiquark) forming it • reliable for large values of boost (rapidity of Z’) • but pseudorapidity cut on leptons: |h| < 2.5 • can correct for dilution to a large extent • efficiency depends only on Y (given incoming type of quarks) because of the symmetry of the detector • some systematic uncertainties (PDF’s…) • note: global lepton reconstruction efficiency depends essentially only on the rapidity of the Z’  for production by a given type of quark flavour, it is independent of the model • at ILC, much better reconstruction: cm kinematics ATLAS Probability to be wrong vs YLedroit et al., hep-ph/0703262 G. Azuelos - LHC2FC

  9. e+e−, m+m−: clean signal, little background (Drell-Yan) • measure s, G, AFB • pileup effects must be understood: effects on resolution, efficiency, purity • is it better to have higher luminosity or higher energy? • t+t−: reconstruction difficult, but possible • measure t polarization and spin correlations • : large QCD background • easier if due to strong interaction resonance Experimental issues at LHC ATLAS - reliance on Monte Carlo:need data and techniques for determination of efficiencies, energy scale, particle mis-ID G. Azuelos - LHC2FC

  10. Discovery reach at the LHC Z’ → ee Julien Morel, Thesis and ATLAS CSC note, arXiv:0901.0512 Present limits: 650-1000 GeV CMS, CERN/LHCC 2006-021 G. Azuelos - LHC2FC

  11. CDDT parametrization M Carena, A. Daleo, B. Dobrescu and T. Tait, PR D70 (2004) 093009 • very general model with 2 Higgs doublets • 15 fermion couplings zf: • couplings to quarks are generation-independent U(1)z charges • anomaly cancellations and possible new fermions must be taken into account • “realistic models” for Tevatron: LEP bounds from contact interactions: G. Azuelos - LHC2FC

  12. B-xLTevatron, 2 fb-1 ATLAS, B-xL, 400 pb-1 Ledroit et al., ATL-PHYS-PUB-2006-024and TeV4LHC: hep-ph/0608322 bounds at Tevatron and early LHC G. Azuelos - LHC2FC

  13. 1 ab-1mass assumed measured at LHC Z’ at the ILC At the ILC, sensitivity s from Z’-Z interference - can also be sensitive to high masses (contact-like interaction) LHC/ILC Interplay, G. Weiglein et al, hep-ph/0410364 G. Azuelos - LHC2FC

  14. stats +syst stats sonly di-lepton resonance interpreted as a techni-rho In context of TC Strawman Model (K. Lane) assume M(rT) = M(wT) G. Azuelos - LHC2FC

  15. ATLAS ATLAS Kaluza-Klein gauge resonances • RS model with bulk matter • SM fermions are localized in the extra dimension: their wave functions overlap with the Higgs boson (confined on the TeV-brane)  hierarchical patterns of effective 4-D Yukawa couplings. • 3 sets of parameters chosen to suppress FCNC and to be consistent with EW precision measurements F. Ledroit et al., JHEP09(2007)071 G. Azuelos - LHC2FC

  16. Kaluza-Klein Graviton resonances CMS 3 parameters: (2 independent) G. Azuelos - LHC2FC

  17. spin determination ATLAS Also,G* → gg and other channels… region distinguishable from Z’ CMS G. Azuelos - LHC2FC

  18. G*KK at the ILC CLIC G. Azuelos - LHC2FC

  19. The littlestHiggs Model - remarks • the small Higgs mass results from non-exact symmetry  pseudoGoldstone boson (pions have mass because quark masses and e.m. break chiral symmetry) • quadratic divergences occur at two-loop level ~ 10 TeV model is not complete UV completion required at ~ 10 TeV • Low energy EW constraints rather severe • FCNC’s at ~ 100 TeV • New particle content G. Azuelos - LHC2FC

  20. low BR Heavy Z, A in LH model WH, ZH, AH arise from [SU(2)  U(1)]2 symmetry  2 mixing angles (like qW): q for ZHq’ for AH Measurement of ZHZh and WHWh couplings needed to test model High luminosity/high energy needed! G. Azuelos - LHC2FC

  21. W’→ ln Potential signal in early years of LHC running - transverse mass - ETmiss: need good determination, account for pileup effects, … G. Azuelos - LHC2FC

  22. T. Rizzo, arXiv:0704.0235v2 W’ →  n • W’ mass difficult to reconstruct: • only transverse mass observable • AFB not easily measurable (assume light RH neutrino) • n direction unknown • mT is max when cos(q) =0 • can be measured in interference region • possibly also in W’ → t b, with t polarization (b tagging at high lumi?) ATLAS, Physics TDR W’ couplings more easily measurable at ILC, where cm is known, but is there enough mass? (produced in association with W or in pairs) G. Azuelos - LHC2FC

  23. W’ in Little Higgs model 300 fb-1 Need high luminosity/high energy G. Azuelos - LHC2FC

  24. W’ at CLIC CLIC • production cross section high, if above threshold • mass measurement from the threshold • cross section measures the coupling strength G. Azuelos - LHC2FC

  25. Z’, W’ in LRSM ee mm G. Azuelos - LHC2FC

  26. CMS result on WR’ Full GEANT detector simulation and reconstruction 30 fb-1 30 fb-1 1 fb-1 CMS Physics TDR, CERN/LHCC 2006-021 G. Azuelos - LHC2FC

  27. Z’, W’ in LRSM q WR* q N  J. Collot, A. FerrariATL-PHYS-98-124, ATL-PHYS-99-034 backgrounds:t tbar DY, WW, ZW, ZZ LRSM bckg: WR,…  cuts on mee, pT(jets) FB asymmetry gives a measure of k = gR/gL (merged jets) G. Azuelos - LHC2FC

  28. fraction in + helicity state for WR+ 30 fb-1 fraction in + helicity state for WR- Z’, W’ in LRSM J. Collot, A. FerrariATL-PHYS-98-124, ATL-PHYS-99-018 backgrounds:t tbar DY, WW, ZW, ZZ G. Azuelos - LHC2FC

  29. fermions: D, S, T have charges +5/3, -4/3, -4/3 new vector gauge bosons: vector bi-leptons 3-3-1 model: • explains 3 families: anomalies cancel, taking all 3 generations together • essentially no background, and detection possible up to ~ 1.4 TeV- can measure FB asymmetry, Z’ massB. Dion et al., Phys.Rev. D59 (1999) 075006, B. Brelier and G.A., ATLAS internal note • at ILC, different 331 models can be distinguished (Barreto et al, hep-ph/0703099) G. Azuelos - LHC2FC

  30. ATL-PHYS-2004-025 300 fb1 100 fb1 VBF D-Y 100 fb1M(WR)=650 GeV 100 fb1 100 fb1 300 fb1 300 fb1 Scalar bileptons: doubly-charged Higgs doubly (and singly) charged Higgs in Higgs triplet models (as in LR symmetric model, Little Higgs model, …) G. Azuelos - LHC2FC

  31. Doubly-charged Higgs in Little Higgs Drell-Yan production, with 100% BR into muons discovery limit of 650 GeV with 10 fb-1 CMS, CERN/LHCC 2006-021 G. Azuelos - LHC2FC

  32. 3rd family • Possibly different couplings to the 3rd family: • LEP constraints weaker • topcolor • distinguish between scalar (A/H) from vector (Z’) • … but difficult to measure • Z’ → t t : poor resolution in mass reconstruction • method assumes collinear approximation: neutrino in same direction as t, with the t massless 2 x 3-vectors for charged particles, 1 x 2-vector for missing pT → 8 input + 2 constraints for 4 x 3 – 2 = 10 deg. of freedom • works when t’s are not back to back (not too heavy Z’) • good reconstruction at ILC, where s and Pmiss is known ! • Z’ → bb : high QCD background • Z’ → t t : high background from QCD production of top • except if resonance is from a strong interaction process • good for ILC, but limited by mass G. Azuelos - LHC2FC

  33. ATLAS FB Asymmetry(parton level, wrt Z’ direction) further observables for 3rd generation • can measure FB asymmetry wrt to Z’ direction • possibility to measure polarization or spin correlations through decay of t or top • collinear approximation fails for very high mass (back-to-back t’s) parton level GA, B. Brelier, D. Choudhury, PA Delsart, RM Godbole, SD Rindani and RK Singh, Les Houches 2005 G. Azuelos - LHC2FC

  34. For heavy quark production, one diagram dominates: sKK/sSM KK excitation of the gluon UED scenarioD.A. Dicus, C.D. McMullen and S. Nandi, PR D65 (2002) 076007 ATLAS 300 fb-1 March, L; Ros, E; Salvachúa, B; ATL-PHYS-PUB-2006-002 G. Azuelos - LHC2FC

  35. top resonance from bulk RS KK gluon B. Lillie, L. Randall and L-T Wang, hep-ph/0701166 - large overlap of KK gluon and top quark wave functions because both are localized towards TeV brane t-tagging fake rate • can also measure spin correlations (tR coupling?) • experimental issues: • b-tagging • strong collimation of jets from top and from W’s • jet mass can be used, as in: • W. Skiba, D. Tucker-Smith hep-ph/0701247 • - can also have graviton resonance to top pairs (or WW), but higher mass(Agashe et al., hep-ph/0701186) G. Azuelos - LHC2FC

  36. ttbar R Frederix and F Maltoni, arXiv:0712.2355 parton level: must fold in efficiency and energy smearing  need precision smearing because cannot distinguish u/d quarks from W decay G. Azuelos - LHC2FC

  37. Jet splitting • Highly boosted di-jet looks like one jet → use algorithm to see if jet splits into two when narrower cone is used jets with pT > 250 GeV Once a jet is found, apply the inclusive kT algorithm to clusters composing it J.M. Butterworth, J.R. Ellis, A.R. Raklev, hep-ph/0702150 G. Azuelos - LHC2FC

  38. G. Azuelos - LHC2FC

  39. di-jet resonances CMS G. Azuelos - LHC2FC

  40. Conclusions • New resonances are potential, early signals of BSM physics • can reach few TeV with first 10 fb-1 • very large QCD backgrounds at LHC • may mask signals • sources of systematic errors difficult to evaluate: • efficiencies, resolutions, energy scale, pileup, • background cross sections • may need higher mass reach  higher energy or higher luminosity?? optimization would require detailed MC simulations with realistic detector design • need to understand their origin: LC: precision measurement of resonance parameters cm kinematics G. Azuelos - LHC2FC

  41. Backups

  42. from Cvetic and Godfrey, hep-ph/9404216 G. Azuelos - LHC2FC

  43. G. Azuelos - LHC2FC

  44. Narrow Graviton Resonance • Spin determination 100 fb-1 spin-2 could be determined (spin-1 ruled out) with 90% CL up to graviton mass of 1720 GeV G. Azuelos - LHC2FC

  45. ExpectedStatistical precision 100 fb-1 Allanach et al., ATL-PHYS-2002-031 • also G  WW , ZZ, jj, mm, tt, hh e.g.:for a resonance observed at mG = 1.5 TeV in ee channelDmG < 10.5 GeV (energy scale error)Ds.B ~ 18%if k/rc = 0.01 (pessimistic) ═› rc =(82±7) x 10-33 m !! G. Azuelos - LHC2FC

  46. 2 from LQ - OPAL G. Azuelos - LHC2FC

  47. W+f++W+ Triplet Higgs Single production Main background from WTWT scattering G. Azuelos - LHC2FC

  48. Right-handed interactions? Z’ : first sign of extended gauge group ? • Left-Right Symmetric Model: • right-handed fermions in doublets  heavy Majorana nR=N • explains low mass of nL (see-saw mechanism) • WR, ZR associated with right-handed sector • larger GUT groups (includes LRSM) triplet Higgs G. Azuelos - LHC2FC

  49. from Almeida et al., arXiv:hep-ph/0702137v1 G. Azuelos - LHC2FC

  50. triggers EW symm. breaking  mass to Z, W, h massless vev for h acquires mass from one-loop gauge interactions 1-loop gauge interactions: t To cancel the top loop,introduce SU(2)L singlet quark TL, and TR The littlestHiggs Model - particles G. Azuelos - LHC2FC

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