1 / 50

A Selection of Exotics with ATLAS

A Selection of Exotics with ATLAS. PHENO2002, 22-24 April 2002 Madison, Wisconsin. Helenka Przysiezniak LAPP, Annecy, on behalf of ATLAS 22 April 2002. Why do we need Exotics? SM - Higgs mechanism does not explain EVERYTHING N.B. a SUSY talk M weak  M planck ?

santa
Download Presentation

A Selection of Exotics with ATLAS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. A Selection of Exotics with ATLAS PHENO2002, 22-24 April 2002 Madison, Wisconsin Helenka Przysiezniak LAPP, Annecy, on behalf of ATLAS 22 April 2002

  2. Why do we need Exotics? SM - Higgs mechanism does not explain EVERYTHING N.B. a SUSY talk Mweak Mplanck ? Parity Violation? Neutrino masses? Proton decay?? EW symmetry breaking? Particle mass hierarchy? Without an abundance of Xtra particles... P.Higgs

  3. Why do we need ATLAS? (and CMS) Inner Detector : Semiconductor Pixel and Strips Straw Tube Tracking Detector (TRT) L  R = 7m1.15m R=12-16m, Z=66-580m -electrons, jets, Etmiss, E  coverage, b-tagging Thin Superconducting Solenoid (B=2T) LAr Electromagnetic Calorimeter : L  R = 13.3m2.25m 3.2 (4.9) E /E= 10%/E0.7% Hadronic Calorimeter : Endcaps LArg Barrel Scintillator-tile L  R = 12.2m4.25m E /E= 50%/E3% (3) Large Superconducting Air-Core Toroids Muon Spectrometer L  R = 25 (46) m11m

  4. Exotics Compositeness(2) Extra Dimensions (4) New Gauge Bosons(1) Strong Symmetry Breaking(3) And much much more...

  5. 1.New Gauge Bosons Parity violation introduced by hand? m = 0 while new experimental data suggest otherwise ? Left-Right Symmetric Model (LRSM): restores parity symmetry at high energy and introduces W+R ,W-R and Z’ and R-handed neutrinos Nl If Majorana ’s , LRSM + SeeSaw  3 light L-handed ’s + 3 heavy R-handed ’s (Nl) R-handed current contributions to m (KL0 -KS0): mWR  1.6 TeV Tevatron: mZ’  630 GeV , mWR  720 GeV(light NR)640 GeV(heavy NR) -less double  decays: mWR  1.1 TeV x (mN /1TeV)-1/4

  6. 1.New Gauge Bosons Search for the decay pp  WR  eNe eeW*R  ee+qiqj Most promising channel prod one to two orders of magnitude higher than Z’ Discovery potential of pp  WR  eNe  2e+2j at the 5 confidence level for 30 and 300 fb-1 in m(Ne) vs m(WR) plot using increasingly tighter cuts from a) to c) - Main backgrounds: Signal  10 Signal/Bgd  5 For Int. Lumi. 300 fb-1 mWR  4 TeV mNe  6 TeV

  7. 2.Compositeness 1-2-3 generations of quarks and leptons Possibly composite structures? More fundamental constituents? Excited (spin 1/2,...) quarks and leptons, Leptoquarks,Diquarks,Dileptons,etc… Direct production of excited spin 1/2 fermions for s   (~m*) f, f’, fs Lagrangian term constants determined by the compositeness dynamics e.g.Excited quarks 1st generation u,d f=f’=fs=1 CDF searches: 200m*760 GeV combined excluded D0 searches: 200m*720 GeV excluded BR80% BR12% BR5% BR<5%

  8. 2.Compositeness Excited quarks of spin 1/2 qg  q*  q channel Signal  10 per year Signal/Bgd  5 per year f=f’=fs=1 For Int. Lumi. 300 fb-1 m* 6.5 TeV Main backgrounds: Excited quark signal significance (left) 300 fb-1 Invariant mass distributions mj for the excited quark signal and backgrounds for =m* =1TeV

  9. 3.Strong Symmetry Breaking Breaking of EW symmetry? Regularization of the quadri-vector boson coupling? Mechanism for generating mf ? Understanding EW symmetry breaking:  Search for new resonances (which could regularize vector boson scattering Xsection)  Study Longitudinal gauge boson pair production (L component provides mass to bosons) e.g.1. Technicolor e.g.2. Chiral Lagrangian model

  10. 3.Strong Symmetry Breaking e.g.1.Technicolor Classical TC Goldstone bosons T are longitudinal d.o.f of W and Z  largely ruled out by precision EW data Extended TC allows generation of mf  does not explain absence of FCNC Walking ETC «walking» coupling constant TC several representations of fundamental family existence of technihadron resonances  Constraints from EW data make it unnatural to explain mTop for all of the above models Top-color-assisted TC mTop arises from new strong top-color interaction

  11. 3.Strong Symmetry Breaking e.g.1.Technicolor Channels investigated Cleanest channel of those with direct production of T bb resonances Mass scenarios considered tt resonances Direct production of T Main backgrounds: 1. WZ continuum production 2. Z+jets (qqgZ,qg qZ,qq ZZ) ttbar, WZ continuum production (qqbar WZ)

  12. 3.Strong Symmetry Breaking e.g.1.Technicolor Direct production of T Reconstructed invariant mass for TWZlll channel. Solid line is signal. Filled area is background. Lower limits required for 5 significance with 30 fb-1 : in some cases, signals are below observability, but combination of signals could provide strong evidence. TWZlll for 30 fb-1 (a) xBRmodel = 0.16 fb xBR5 discovery = 0.025 fb TWlbbfor 30 fb-1 (c) xBRmodel = 0.064 fb xBR5 discovery = 0.15 fb

  13. 4.Extra Dimensions Large (1mm,1/TeV) Xtra D’s «à la» Arkani Dimopoulos Dvali - MEffPlanckMweak Gravity propagates in the Xtra Ds Hence its weakness: it is diluted into the Xtra Ds Direct or virtual production of Gravitons TeV-1 Xtra D’s SM gauge fields propagate in «small» Xtra Ds 4D KK excitations of gauge fields Small Xtra D’s «à la» Randall Sundrum- MEffPlanckMweak «warped» metric - only 1 Xtra D 4D KK excitations of Graviton Higgs-like Radion scalar etc...

  14. 4.Extra Dimensions Large Xtra D’s (ADD) Graviton direct production jet() + ETmisssignature ETmiss for signal and background for 100 fb-1 With  Xtra D’s of size R, observed Newton constant related to fundamental scale of gravity MD: Single jet: Single  (limited sensitivity): Main backgrounds: jet+Z(), jet+Wjet+(e,,) Main backgrounds: Z(), W(), W (e,,)

  15. 4.Extra Dimensions Large Xtra D’s (ADD) Max reach in MD for 100 fb-1 for a jet of ET>ETmiss for Smax=S/B>5 and Smin=S/7B>5 and for S>100 Single jet channel 100 fb-1 high lumi Smax>5, S>100, ET>1TeV for =2,3,4 MDmax = 9.1, 7.0 and 6.0 TeV  : exploit variation of  vs Ecm (Ecm1)/ (Ecm2) almost independent of MD but varies with 

  16. 4.Extra Dimensions TeV-1 Xtra D’s Usual 4D + Small (TeV-1) Xtra D’s + Large Xtra D’s (>>TeV-1): fermions live in 3-brane, Gravitons go everywhere, SM gauge bosons propagate in 4D+Small Xtra D’s  4D KK excitations of gauge bosons (here: 1 small Xtra D) Mc compactification scale Masses of gauge bosons KK modes: Mn2= (nMc)2+M02 e+e-, +- decays of  and Z bosons Signal  10 Signal/Bgd  5 100 fb-1 high lumi Peak in mll detected if Mc < 5.8 TeV 300 fb-1 high lumi Mc< 13.5 TeV excluded@95%C.L. Mll for e+e- (full line) and +(dashed). Lowest lying KK excitation at 4 TeV.

  17. 4.Extra Dimensions Small Xtra D’s (RS) Universe with two 4-d surfaces bounding a slice of 5-d spacetime SM fields live on TeV brane (y=) Gravity lives everywhere: TeV (y=), Planck (y=0) branes and in the bulk Exponentially warped fifth dimension: Two massless excitations: Graviscalar Graviton Radion 1/k curvature radius (k of order of Planck scale) rc volume radius

  18. 4.Extra Dimensions Small Xtra D’s (RS) Higgs-like Radion scalar Log(BR) vs mass of scalar for SM Higgs (top) and for radion =0 (middle) and =0 (bottom), for =1 TeV, mh =125 GeV. Mechanism naturally stabilizing size of Xtra D to krc=35(Goldberger & Wise): add bulk scalar  radion scalar most likely lighter than J=2 Kaluza Klein excitations. Three parameters: m , ,  (mass,scale,-H mixing) Channelsinvestigated:   ,   ZZ(*)  4 leptons   hh  bb,bb

  19. 4.Extra Dimensions Small Xtra D’s (RS) Higgs-like Radion scalar 100fb-1, = 0, mh=125 GeV/c2, = 1(10) TeV S/B~10(.1) for 80<m<160GeV/c2 ZZ(*)S/B~100(1) for 200<m<600GeV/c2 30fb-1 ,  = 0, mh=125 GeV/c2 ->hh->bb If B=0, Signal/Bgd>5, Signal>10 max=4.6  5.7 TeV for m= 300  600 GeV/c2 30fb-1 ,  = 0, mh=125 GeV/c2 ->hh->bb Signal/Bgd>5, Signal>10 max=1.4TeV for m= 600 GeV/c2

  20. Conclusion and Outlook Un? biased selection of Exotics studies with ATLAS: Lots going on in Xtra D ’s Theory advancing at TGV pace e.g. black hole production @ LHC!!! Experimentalists try to follow LHC will definitely be rich discovery terrain !!

  21. Annexe -Add references and names for models and for analyses? -Give Tevatron (LEP and other) limits when they exist -are the atlas limits @95%CL or 90%? -Int. Lumi for low and high lumi running??? -Mention for each analysis the experimental signatures and cuts -put main background for each analysis -mention authors of theories -add analysis by Polesello and Azuelos -add technicolor and other Tevatron limits (those for Azuelos+Polesello analysis from the lesh proc) -check for ??? Everywhere and answer them...

  22. Annexe LAr Electromagnetic Calorimeter : E /E= 10%/E???%/E0.7% (sampling+electronics and pile up+non uniformity constant) thickness>24Xo in barrel and >26Xo in endcaps Hadronic Calorimeter : LAr Hadronic endcaps Scintillator-tile barrel (thickness 9.2 at =0) complete???

  23. Annexe 1.New Gauge Bosons Parity violation introduced by hand? m = 0 while new experimental data suggest otherwise ? Left-Right Symmetric Model (LRSM): broken symmetry  parity violation @ low energy restores parity symmetry at high energy by extending SU(2)L  U(1)Y  SU(2)L  SU(2)R  U(1)B-L and thereby introducing: W+R ,W-R and Z’ as well as right-handed neutrinos Nl If Majorana ’s , LRSM + SeeSaw mechanism  3 light left-handed ’s + 3 heavy right-handed ’s (Nl) R-handed current contributions to KL0 -KS0 m : mWR  1.6 TeV Tevatron: mZ’  630 GeV , mWR  720 GeV (light NR) 640 GeV (heavy NR) -less double  decays: mWR  1.1 TeV x (mN /1TeV)-1/4

  24. Annexe 1.New Gauge Bosons Search for the decay pp  Z’  NeNe eW*ReW*R  ee+qiqjq’iq’j - - Observability of pp  Z' Ne Ne 2e+4jets at the 5 confidence level for 300 fb-1 in m(Ne) vs m(Z') plot Main backgrounds: Signal  10 Signal/Bgd  5 For Int. Lumi. 300 fb-1 mZ’  4.3 TeV mNe  1.2 GeV for m(N)/m(Z’)  0.1

  25. Annexe 1.New Gauge Bosons Search for the decay pp  W’  WZ Not principal discovery channel Ratio of cross section required for a 5 significance over that of the SM??? Main backgrounds: In LRSM, if WR is not kinematically allowed to decay to lepton + NR For Int. Lumi. 300 fb-1 mW’  2.8 TeV

  26. Annexe 1.New Gauge Bosons Search for the decay pp  W’  WZ E6 model: Z’=cos Z +sin Z Not principal discovery channel Unpublished Leptonic channel: weak sensitivity to mixing angle All channels: Z’WW sensitive to sin

  27. Annexe 2.Compositeness Excited quarks of spin 1/2 Total decay width  and relative BR=(q* qV)/V (q* qV)

  28. Annexe 2.Compositeness Excited quarks of spin 1/2 qg  q*  qg Main backgrounds: Invariant mass distributions mjj for f=f’=fs=1 (dashed),f=f’=fs=0.5 (dashed dotted), backgrounds (solid) for =m* =2TeV Signal  10 Signal/Bgd  5 For Int. Lumi. 300 fb-1 m* 6.6 TeV Signal significance vs =m*

  29. Annexe 2.Compositeness Excited leptons Unpublished Zee channel Signal  5 Signal/Bgd  5 f=f’=1 Signal significance vs =m* for 300 fb-1 Zeeeeee channel For Int. Lumi. 300 fb-1 m*=  3 TeV We channel Signal  100 f=f’=1 For Int. Lumi. 300 fb-1 m*=  3 TeV

  30. Annexe 2.Compositeness Excited quarks of spin 1/2 For Int. Lumi. 300 fb-1 m* 7 TeV  qW channel m* 4.5 TeV  qZ channel Signal significance for the qW channel (solid lines) and for the qZ channel (dashed lines) Unpublished

  31. Annexe 3.Strong Symmetry Breaking Breaking of EW symmetry? Regularization of the quadri-vector boson coupling? Mechanism for generating mf ? «Triviality»???: impossible to construct interacting theory of scalars in 4d which is valid to arbitrary short distance scales (problem is absent in SUSY models). Understanding EW symmetry breaking:  Study Longitudinal gauge boson pair production in high energy regime (since it is the L component which provides mass to these bosons)  Search for new resonances (which could regularize vector boson scattering Xsection)

  32. Annexe 3.Strong Symmetry Breaking e.g.1.Technicolor Classical TC Goldstone bosons T are longitudinal d.o.f of W and Z, replica of QCD  largely ruled out by precision EW data Extended TC allows generation of mf  does not explain absence of FCNC Walking ETC «walking» coupling constant TC , several representations of fundamental family , existence of technihadron resonances  Constraints from EW data make it unnatural to explain mTop in all these models Top-color-assisted TC mTop arises from new strong top-color interaction

  33. Annexe 3.Strong Symmetry Breaking e.g.1.Technicolor Observability of other channels tt resonances10 (100) fb-1 mtt=500GeV: xBR5 discovery = 17 (5.5) fb mtt=750GeV: xBR5 discovery = 7.3 (2.3) fb mtt=1000GeV: xBR5 discovery = 2.55 (0.81) fb T Tbbfor 30 fb-1 m=500 (800) GeV: xBRmodel = 0.161 (0.033) fb Signal/Bgd=60 (35) xBR5 discovery = 0.013 (0.0046) fb

  34. Annexe 3.Strong Symmetry Breaking e.g.1.Technicolor Observability of channels Expected significance, xBR (fb) predicted by model, xBR required for 5 significance, for WZlll for 30 fb-1. Expected significance, xBR (fb) predicted by model, xBR required for 5 significance, for Wlbb for 30 fb-1 Minimum values of xBR (fb) necessary for a 5 discovery, for tt resonances, for 10 fb-1 and 100 fb-1 Expected significance, xBR (fb) predicted by model, xBR required for 5 significance, for bb for 30 fb-1

  35. Annexe 3.Strong Symmetry Breaking e.g.1.Technicolor T production via WLZL fusion Quark fusion process dominates, but vector boson fusion has forward jet tag which helps to suppress background. Complementary channel to fusion. Main backgrounds (same as direct prod): 1. WZ continuum production 2. Z+jets (qqgZ,qg qZ,qq ZZ) ttbar, WZ continuum production qq  qqT  qqWT0  qqlbb ZL(WL) Observability of qqqq T qq W T0 xBRmodel = 2.2 fb Signal/Bgd=1.1 versus Signal/Bgd=2.1 in direct production. xBR5 discovery = 12 fb

  36. Annexe 3.Strong Symmetry Breaking e.g.2.Chiral Lagrangian model Based on Chiral Perturbation Theory (ChPT) Study WL WL scattering Inverse Amplitude Method (IAM) : parameters L1 and L2  Unitarity is not violated IAM model predicts resonances for certain parameter values Resonant WL ZL  WL ZL scattering ??? What values of L1 and L2 in the plot??? Main backgrounds: 1. Irreducible continuum WZ (negligible), 2. Reducible QCD (e.g. main Z+jets,ttbarWWbbbar) MRes= 1.5 TeV for qqqqWZ qqjjll Nsignal=8  14 for MRes= 1.5  1.2 TeV Nbackground=1.3  3 for 30 fb-1

  37. Annexe 3.Strong Symmetry Breaking e.g.2.Chiral Lagrangian model Based on Chiral Perturbation Theory (ChPT) Effective Chiral Lagrangian with operators up to dimension 4. Study WL WL scattering. The Inverse Amplitude Method (IAM) with parameters L1 and L2 used such that Unitarity is not violated. For certain values of the parameters, IAM model predicts resonances. Resonant WL ZL  WL ZL scattering Nsignal=8 (14) for MV = 1.5 (1.2) TeV Nbackground=1.3 (3) for 30 fb-1

  38. Annexe 3.Strong Symmetry Breaking e.g.2.Chiral Lagrangian model Non resonant WL+WL+ and WL ZL WL ZL processes IAM model parameters L1 and L2 for 500 fb-1 !! L1=0.003 (0.01)and L2=0 Signal/Bgd=2.7 (1.43) MT of ll+Etmiss for signal (continuous:K matrix unit. and dashed: 1TeV Higgs) and backgrounds (full histo) for 100 fb-1 ??? Main backgrounds: 1. Irreducible continuum WTWT bremsstrahlung, gluon exchange, Wttbar, WZ MT of WZ system for signal and backgrounds for 500 fb-1. WL+WL+ l+l- WL ZL WL ZL  lll Main backgrounds: 1. Irreducible continuum WZ, 2. Reducible QCD (e.g. main Z+ttbarZ+WWbbbar Z+lWbbbar)

  39. Annexe 4.Extra Dimensions Large Xtra D’s (ADD) If MD~1TeV then R~1032/-16 mm implying that if 2, R is smaller than the scales of order 1mm down to which gravitational interactions have been probed. =1 excluded since it would imply deviations of the Newton law of gravity. =2 is not very likely because of cosmological arguments, in particular graviton emission from Supernovae 1987a implies that MD>50 TeV. In this picture, the apparent weakness of observed gravity is due to its dilution by the spreading of its field into the additional dimensions. It should be noted that the hierarchy problem is not solved in the simplest implementation of the idea; the large ratio MP/MW is replaced by the large value of RMD .When an Xtra D is compactified on a circle with size R, particles propagating exclusively in the Xtra D appear, from a 4d viewpoint, as a tower of massive states. The charactersitic mass splitting of these KK states is of the order of 1/R. In particular spin 2 gravitons propagating in the Xtra D will appear to be massive states whose coupling to ordinary matter is determined only by gravitational interactions and is therefore known. However the SM particles cannot be allowed to propagate into the Xtra D as there is not excited electron with a mass below 100 GeV. For energies much larger than the mass splitting, the discrete spectrum can be approximated by a continuum with a density of states dN/dm~m-1. Since these gravitons interact very weakly with ordinary matter, the emission gives rise to missing transverse energy signatures.

  40. Annexe 4.Extra Dimensions Large Xtra D’s (ADD) 100 fb-1 high lumi Smax>5, S>100, ET>1TeV for =2,3,4 MDmax = 9.1, 7.0 and 6.0 TeV 30 fb-1 low lumi, ‘’, S>50 MDmax = 7.7, 6.2 and 5.2 TeV  : exploit variation of  vs Ecm (Ecm1)/ (Ecm2) almost independent of MD but varies with 

  41. Annexe 4.Extra Dimensions Large Xtra D’s (ADD) Virtual Exchange in particular  and lepton pair production. deviations in Drell-Yan Xsec. and Asym. w.r.t. SM 5000 Lower cut ???Mmin vs maximal reach MD at 5 level for low lumi 10 fb-1 (solid) and high lumi 100 fb-1 (dashed). Low (high) lumi, =52 Di-photon: MDmax = 4.9-6.3 (6.3-7.9) TeV Di-lepton: MDmax = 5.1-6.6 (6.6-7.9) TeV 1000 8000 4500 N.B. cannot really distinguish number of Xtra D and energy scale

  42. Annexe 4.Extra Dimensions Large Xtra D’s (ADD) Di photon invariant mass. Total signal for n=3 and various values of Ms (left), for Ms=4.7 TeV and various values of n (right). FB asymmetry vs Mll for n=3 and various values of Ms (left), for Ms=4.7 TeV and various values of n (right). Errors are presented by grey bars except for n=2, and correspond to 100 fb-1 .

  43. 4.Extra Dimensions TeV-1 Xtra D’s Usual 4D + Small (TeV-1) Xtra D’s + Large Xtra D’s (>>TeV-1): fermions live on 3 brane, Gravitons live everywhere, SM gauge bosons propagate in 4D+Small Xtra D’s  4D KK excitations of gauge bosons (here: 1 small Xtra D) Model completely specified by Mc compactification scale: masses of the KK modes of gauge bosons Mn2= (nMc)2+M02 e+e-, +- decays of  and Z bosons  striking signature

  44. Annexe 4.Extra Dimensions TeV-1 Xtra D’s Precision EW measurements give Mc< 4 TeV excluded @95% C.L. for the reference model considered here. Recent paper dominated by LEP2 data gives Mc< 6.8 TeV excluded @95% C.L. but certain inconsistencies in this result, namely an unphysical negative value for Mc is obtained.

  45. Annexe 4.Extra Dimensions Small Xtra D’s (RS) KK Graviton excitations: narrow multi TeV resonances Scale: where is the reduced 4d Planck scale. Masses of graviton resonances: where xn are roots of Bessel function of order 1. Couplings 1/  low coupling constant: conservative estimate of prod  narrow resonances

  46. Annexe 4.Extra Dimensions Small Xtra D’s (RS) KK Graviton excitations: narrow multi TeV resonances G  e+ e- decay mode «model independent» study BR (fb) vs MG for G  e+ e- in the test model and BR (fb) for signal significance Smallest BR (fb) vs MG for G  e+ e- for which the spin-2 hypothesis is favoured over the spin-1 hypothesis, @90,95 and 99% C.L. The test BR (fb) is also shown. Assuming resonance  mdet Nsignalmin =max(5NBgd ,10) for 100 fb-1

  47. Annexe 4.Extra Dimensions Small Xtra D’s (RS) KK Graviton excitations: narrow multi TeV resonances G  e+ e- decay mode «model independent» study Angular distribution of data (points) in test model for mG =1000 GeV and 100 fb-1 Stacked histo shows contributions from SM, gg and qq prod. Curve shows distribution expeced from spin=1 resonance.

  48. Annexe Lepton Flavour Violation  Super K results suggest  -  mixing  LFV. In SUSY models, LFV may have implications for the pattern of slepton masses and mixings. LFV introduced into SUSY at one loop level R-handed ’s coupling to the lepton L-handed doublets (NiLjH) One loop rad. corr.  LNumberV terms in mass matrices for L-sleptons. Minimal SUGRA decays: (ATLAS point 5: m0=100GeV, m1/2=300GeV, A0=300GeV,tan=10 and sgn =+) Without LFV: With LFV:  LFV decays give a m+ - signal producing an asymmetry between m+ - and e+ - final states Unseparable  Small BR

  49. Annexe Lepton Flavour Violation Minimal SUGRA+LFV m+ - signal search Search for multiple jets and ETmiss and look at opposte sign dilepton Mll Visible mass distributions l+-h-+ -l+-h+- (solid line) and +-h-+ from LFV with BR=10% (dashed-dotted line). SM bgd cancel in this plot.  decay sensitive to the same LFV as signal considered here giving BR()110-9

  50. Annexe Super LHC Large Xtra Ds direct Graviton production Search for new gauge bosons 5 discovery limits for Z’ mass in TeV in the +- channel. 5 discovery limits achieved on MD in TeV. Excited quarks Significance of q*q vs mq*.

More Related