Anomalously interacting extra bosons and first results of their search at LHC

1. Anomalously interacting extra bosons and first results of their search at LHC R R Z* V.A. Bednyakov, M.V. Chizhov, J.A. Budagov, I.V. Yeletskikh (JINR, Dubna) L L 22.08.2011, Moscow, MSU, 15thLomonosov Conference

2. Anomalously interacting extra bosons • M. V. Chizhovand G. Dvali, Origin and Phenomenology of Weak-Doublet Spin-1 Bosons,arXiv:0809.0924 • M. V. Chizhov, Disentangling between Z’ and Z* with first LHC data,arXiv:0807.5087 • M. V. Chizhov, Sensitivity to new physics: aevs am, Phys. Part. Nucl. Lett. 6 (2009) 361 • M. V. Chizhov, V. A. Bednyakov and J. A. Budagov, Proposal for chiral bosons search at LHCvia their unique new signature, Phys. Atom. Nucl. 71 (2008) 2096 • M.V. Chizhov, V.A. Bednyakov, J.A. Budagov. On resonance search in dijet events at the LHC. arXiv:1106.4161 • M.V. Chizhov, V.A. Bednyakov, J.A. Budagov, A unique signal of excited bosons in dijet data from pp-collisions. arXiv:1010.2648 • M.V. Chizhov, V.A. Bednyakov, J.A. Budagov, Anomalously interacting extra neutral bosons. arXiv:1005.2728

4. k k k k k k j j j j j j “Standard” EW physics L L R R L L Z Z’ Z* L L L L L L Chirality changes

5. Analogy with Excited particles: It is possible for exited electron e*, why not “exited” Z* ? The Z*-boson has different interactions with matter than Z’ !

6. We have Extension of the SM or FromTevatron constraints M > 1 TeV Phys. Rev. Lett. 99 171802 (2007) we assume that L = M = 1 TeV g is SU(2)L coupling

7. Our Extension of the SM Usually extra gauge Z’- and W’-bosons appear via U(1)’ or ajoint SU(2)’ presentations of extended Standard Model. The new spin-1 W*- and Z*-bosons (with Higgs doublet quantum numbers) belong to fundamental presentation of weak SU(2)W To be concrete consider model:

8. How to look for Z*-boson at LHC ? Select pp → Z’/Z*X→ ℓ+ℓ-X inclusive processes and study Invariant dilepton mass distributions, FIRST. Z BUT: Several models predict high mass resonances that could decay into dileptons (Z’, G, TC, KK, …) TOO! Z’ Z* MZ

9. e - dL,R Z* e - dL,R dR,L The Key feature is Angular distribution In contrast to the Z‘and W'bosons the excited bosons have anomalous couplings to matter. Z’ dL,R This leads to some distinctive signatures of their production at the hadron colliders. See Below -> e + e +

10. Lepton transverse momentum distributions Z No Jacobian peak at half-mass PT for Z*-boson Z’ Z* MZ /2

12. Pseudorapidity and acceptance Z' Z* Z* Z'

13. Example estimationswithCalcHEP(by M.Chizhov) In the case that such bosons will be observed as resonance peaks above the Z boson tail in the invariant dilepton mass distribution, we suggest to investigate in addition two more experimentally accessible distributions already on the early stage of the LHC data-taking. These are the differential distributions as functions of a transverse momentum and the Collins–Soperscattering angle of the lepton. Both distributions are related to the spin properties of the new boson and should play crucial role in the analysis of their interactions.

14. Discovery of the peak

15. Lepton transverse momentum distributions 3sdifference

16. Lepton angular distributions in the Collins-Soper frame (centre-edge asymmetry ACE) G. Gounaris et al., Int. J. Mod. Phys. A 8 (1993) 3285. 7sdifference

17. COMPLETENESS in the spin-1 and graviton angular distributions is not complete!

18. LHC promises stronger limits

19. First search for anomalously interacting extra bosonsat LHC

20. Search at LHC with ATLAS Detector only! Inner Detector |η|<2.5, solenoid B=2T Si Pixels, Si strips, TRT Tracking and vertex-finding e/π separation Resolution: σ/pT~3.8x10-4pT[GeV]⊕0.015 EM calorimeter |η|<3.2 LAr/Pb accordion structure e/γ trigger, id + measurement E-resolution: σ/E ~ 10%/√E • Muon Spectrometer • |η|<2.7 • Toroid B-Field • Muon Momentum resolution < 10% up to ~ 1 TeV • HAD calorimeter • |η|<3.2 (Forward Calo. |η|<4.8) • Scint./Fe tiles in the central, W(Cu)/LAr in fwd region • Trigger, jets + missing Et • E-resolution: σ/E ~ 50%/√E ⊕ 0.03

21. pp → W’/W*X→ ℓ±X

26. .THE FIRST DIRECT MEASUREMENT!

28. pp → Z’/Z*X→ ℓ+ℓ-X

31. Z* Z* Z* Again the first direct measurement!

33. A unique signal of excited bosons indijetdata from pp-collisions Dijet η-distribution: signal vs background It could be a possible novel signal of new physics in dijet data at the hadron colliders. Usually it is accepted that all exotic models predict that these two jets populate the central (pseudo)rapidity region where y1,2 ≃ 0. Contrary, the excited bosons do not contribute into this region, but produce an excess of dijet events over the almost flat QCD background in another region.

34. Conclusions Phenomenological consequences of the Standard Model extension by new spin-1 chiral fields with the internal quantum numbers of the electroweak Higgs doublets are given. (There are at least three different classes of theories, all motivated by the hierarchy problem, which predict new vector weak-doublets with masses not far from the electroweak scale.) These neutral chiralZ*-bosons can be observed at LHC as a Breit-Wigner resonance peak in the dilepton mass distributions (in the same way as the well-known extra gauge Z’ bosons).This includes them into a list of very interesting objects for early searches with the first LHC data. The Z*-bosons have unique signatures in transverse momentum, angular and pseudorapidity distributions of the final leptons, which strongly allow one to distinguish them from the other resonances. Dubna and PINP (O.Fedin) groups are performing search for these bosons at LHC. Our work with 1/fb data is under way. We expect new results soon.

35. Thanks a lot for your attention ! R R Z* L L

36. Jacobianfor