Skip to main content
SpringerLink
Log in

Probing anomalous tbW couplings in single-top production using top polarization at the Large Hadron Collider

  • Published:
Journal of High Energy Physics Aims and scope Submit manuscript

Abstract

We study the sensitivity of the Large Hadron Collider (LHC) to anomalous tbW couplings in single-top production in association with a W − boson followed by semilep-tonic decay of the top. We calculate top polarization and the effects of these anomalous couplings to it at two centre-of-mass (cm) energies of 7 TeV and 14 TeV. As a measure of top polarization, we look at various laboratory frame distributions of its decay products, viz., lepton angular and energy distributions and b-quark angular distributions, without requiring reconstruction of the rest frame of the top, and study the effect of anomalous couplings on these distributions. We construct certain asymmetries to study the sensitivity of these distributions to anomalous tbW couplings. The W t single-top production mode helps to isolate the anomalous tbW couplings in contrast to top-pair production and other single-top production modes, where other new-physics effects can also contribute. We find separate limits on real and imaginary parts of the dominant anomalous coupling f2R which may be obtained by utilizing these asymmetries at the LHC.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. CDF collaboration, F. Abe et al., Evidence for top quark production in \( p\overline p \) collisions at \( \sqrt {s} = 1.8 \) TeV, Phys. Rev. Lett. 73 (1994) 225 [hep-ex/9405005] [INSPIRE].

    Article  ADS  Google Scholar 

  2. CDF and D0 collaboration, A Combination of CDF and D0 results on the mass of the top quark, hep-ex/0703034 [INSPIRE].

  3. I.I. Bigi, Y.L. Dokshitzer, V.A. Khoze, J.H. Kuhn and P.M. Zerwas, Production and Decay Properties of Ultraheavy Quarks, Phys. Lett. B 181 (1986) 157 [INSPIRE].

    ADS  Google Scholar 

  4. K. Huitu, S. Kumar Rai, K. Rao, S.D. Rindani and P. Sharma, Probing top charged-Higgs production using top polarization at the Large Hadron Collider, JHEP 04 (2011) 026 [arXiv:1012.0527] [INSPIRE].

    Article  ADS  Google Scholar 

  5. M. Arai, K. Huitu, S.K. Rai and K. Rao, Single production of sleptons with polarized tops at the Large Hadron Collider, JHEP 08 (2010) 082 [arXiv:1003.4708] [INSPIRE].

    Article  ADS  Google Scholar 

  6. R.M. Godbole, K. Rao, S.D. Rindani and R.K. Singh, On measurement of top polarization as a probe of \( t\overline t \) production mechanisms at the LHC, JHEP 11 (2010) 144 [arXiv:1010.1458] [INSPIRE].

    Article  ADS  Google Scholar 

  7. D. Choudhury, R.M. Godbole, S.D. Rindani and P. Saha, Top polarization, forward-backward asymmetry and new physics, Phys. Rev. D 84 (2011) 014023 [arXiv:1012.4750] [INSPIRE].

    ADS  Google Scholar 

  8. E.L. Berger, Q.-H. Cao, C.-R. Chen and H. Zhang, Top Quark Polarization As A Probe of Models with Extra Gauge Bosons, Phys. Rev. D 83 (2011) 114026 [arXiv:1103.3274] [INSPIRE].

    ADS  Google Scholar 

  9. A. Heinson, A. Belyaev and E. Boos, Single top quarks at the Fermilab Tevatron, Phys. Rev. D 56 (1997) 3114 [hep-ph/9612424] [INSPIRE].

    ADS  Google Scholar 

  10. T. Stelzer, Z. Sullivan and S. Willenbrock, Single top quark production at hadron colliders, Phys. Rev. D 58 (1998) 094021 [hep-ph/9807340] [INSPIRE].

    ADS  Google Scholar 

  11. A. Belyaev, E. Boos and L. Dudko, Single top quark at future hadron colliders: Complete signal and background study, Phys. Rev. D 59 (1999) 075001 [hep-ph/9806332] [INSPIRE].

  12. E. Boos, L. Dudko and T. Ohl, Complete calculations of \( Wb\overline b \) and \( Wb\overline b \) + jet production at Tevatron and LHC: Probing anomalous W tb couplings in single top production, Eur. Phys. J. C 11 (1999) 473 [hep-ph/9903215] [INSPIRE].

    ADS  Google Scholar 

  13. T.M. Tait, The tW − mode of single top production, Phys. Rev. D 61 (2000) 034001 [hep-ph/9909352] [INSPIRE].

    ADS  Google Scholar 

  14. D. Espriu and J. Manzano, Measuring effective electroweak couplings in single top production at the LHC, Phys. Rev. D 65 (2002) 073005 [hep-ph/0107112] [INSPIRE].

    ADS  Google Scholar 

  15. D. Espriu and J. Manzano, A Study of top polarization in single top production at the CERN LHC, Phys. Rev. D 66 (2002) 114009 [hep-ph/0209030] [INSPIRE].

    ADS  Google Scholar 

  16. T.M. Tait and C.-P. Yuan, Single top quark production as a window to physics beyond the standard model, Phys. Rev. D 63 (2000) 014018 [hep-ph/0007298] [INSPIRE].

    ADS  Google Scholar 

  17. The CDF collaboration, T. Aaltonen et al., Measurement of W-Boson Polarization in Top-quark Decay in ppbar Collisions at \( \sqrt {s} = 1.96 \) TeV, Phys. Rev. Lett. 105 (2010) 042002 [arXiv:1003.0224] [INSPIRE].

    Article  ADS  Google Scholar 

  18. D0 collaboration, V.M. Abazov et al., Measurement of the W boson helicity in top quark decays using 5.4 fb −1 of \( p\overline p \) collision data, Phys. Rev. D 83 (2011) 032009 [arXiv:1011.6549] [INSPIRE].

    ADS  Google Scholar 

  19. C.-R. Chen, F. Larios and C.-P. Yuan, General analysis of single top production and W helicity in top decay, Phys. Lett. B 631 (2005) 126 [hep-ph/0503040] [INSPIRE].

    ADS  Google Scholar 

  20. ATLAS collaboration, G. Aad et al., Measurement of the W-boson polarisation in top quark decays in pp collision data at \( \sqrt {s} = 7 \) TeV using the ATLAS detector, ATLAS-CONF-2011-037 (2011).

  21. CMS collaboration, S. Chatrchyan et al., Measurement of the Polarization of W Bosons with Large Transverse Momenta in W +Jets Events at the LHC, Phys. Rev. Lett. 107 (2011) 021802 [arXiv:1104.3829] [INSPIRE].

    Article  ADS  Google Scholar 

  22. J. Aguilar-Saavedra, N. Castro and A. Onofre, Constraints on the Wtb vertex from early LHC data, Phys. Rev. D 83 (2011) 117301 [arXiv:1105.0117] [INSPIRE].

    ADS  Google Scholar 

  23. C.D. White, S. Frixione, E. Laenen and F. Maltoni, Isolating Wt production at the LHC, JHEP 11 (2009) 074 [arXiv:0908.0631] [INSPIRE].

    Article  MathSciNet  ADS  Google Scholar 

  24. S. Frixione, E. Laenen, P. Motylinski, B.R. Webber and C.D. White, Single-top hadroproduction in association with a W boson, JHEP 07 (2008) 029 [arXiv:0805.3067] [INSPIRE].

    Article  ADS  Google Scholar 

  25. S. Frixione, E. Laenen, P. Motylinski and B.R. Webber, Single-top production in MC@NLO, JHEP 03 (2006) 092 [hep-ph/0512250] [INSPIRE].

    Article  ADS  Google Scholar 

  26. CMS collaboration, S. Chatrchyan et al., Measurement of the t-channel single top quark production cross section in pp collisions at \( \sqrt {s} = {7} \) TeV, Phys. Rev. Lett. 107 (2011) 091802 [arXiv:1106.3052] [INSPIRE].

    Article  ADS  Google Scholar 

  27. J. Aguilar-Saavedra, J. Carvalho, N.F. Castro, F. Veloso and A. Onofre, Probing anomalous Wtb couplings in top pair decays, Eur. Phys. J. C 50 (2007) 519 [hep-ph/0605190] [INSPIRE].

    Article  ADS  Google Scholar 

  28. W. Bernreuther, P. Gonzalez and M. Wiebusch, The Top Quark Decay Vertex in Standard Model Extensions, Eur. Phys. J. C 60 (2009) 197 [arXiv:0812.1643] [INSPIRE].

    Article  ADS  Google Scholar 

  29. P.L. Cho and M. Misiak, b → sγ decay in SU(2) L × SU(2) R × U(1) extensions of the Standard Model, Phys. Rev. D 49 (1994) 5894 [hep-ph/9310332] [INSPIRE].

    ADS  Google Scholar 

  30. F. Larios, M. Perez and C. Yuan, Analysis of tbW and ttZ couplings from CLEO and LEP/SLC data, Phys. Lett. B 457 (1999) 334 [hep-ph/9903394] [INSPIRE].

    ADS  Google Scholar 

  31. G. Burdman, M. Gonzalez-Garcia and S. Novaes, Anomalous couplings of the third generation in rare B decays, Phys. Rev. D 61 (2000) 114016 [hep-ph/9906329] [INSPIRE].

    ADS  Google Scholar 

  32. B. Grzadkowski and M. Misiak, Anomalous Wtb coupling effects in the weak radiative B-meson decay, Phys. Rev. D 78 (2008) 077501 [arXiv:0802.1413] [INSPIRE].

    ADS  Google Scholar 

  33. J. Drobnak, S. Fajfer and J.F. Kamenik, Interplay of t → bW Decay and B q Meson Mixing in Minimal Flavor Violating Models, Phys. Lett. B 701 (2011) 234 [arXiv:1102.4347] [INSPIRE].

    ADS  Google Scholar 

  34. B. Grzadkowski and Z. Hioki, New hints for testing anomalous top quark interactions at future linear colliders, Phys. Lett. B 476 (2000) 87 [hep-ph/9911505] [INSPIRE].

    ADS  Google Scholar 

  35. S.D. Rindani, Effect of anomalous t b W vertex on decay lepton distributions in e + e − → \( t\overline t \) and CP-violating asymmetries, Pramana 54 (2000) 791 [hep-ph/0002006] [INSPIRE].

    Article  ADS  Google Scholar 

  36. B. Grzadkowski and Z. Hioki, Angular distribution of leptons in general \( t\overline t \) production and decay, Phys. Lett. B 529 (2002) 82 [hep-ph/0112361] [INSPIRE].

    ADS  Google Scholar 

  37. B. Grzadkowski and Z. Hioki, Decoupling of anomalous top decay vertices in angular distribution of secondary particles, Phys. Lett. B 557 (2003) 55 [hep-ph/0208079] [INSPIRE].

    ADS  Google Scholar 

  38. Z. Hioki, Probing anomalous top couplings through the final lepton angular and energy distributions at polarized NLC, hep-ph/0104105 [INSPIRE].

  39. Z. Hioki, A New decoupling theorem in top quark physics, hep-ph/0210224 [INSPIRE].

  40. K. Ohkuma, Effects of top quark anomalous decay couplings at γγ colliders, Nucl. Phys. Proc. Suppl. 111 (2002) 285 [hep-ph/0202126] [INSPIRE].

    Article  ADS  Google Scholar 

  41. R.M. Godbole, S.D. Rindani and R.K. Singh, Lepton distribution as a probe of new physics in production and decay of the t quark and its polarization, JHEP 12 (2006) 021 [hep-ph/0605100] [INSPIRE].

    Article  ADS  Google Scholar 

  42. M. Beccaria, F.M. Renard and C. Verzegnassi, Electroweak supersymmetric effects on high energy unpolarized and polarized single top production at CERN LHC, Phys. Rev. D 71 (2005) 033005 [hep-ph/0410089] [INSPIRE].

    ADS  Google Scholar 

  43. J. Vermaseren, New features of FORM, math-ph/0010025 [INSPIRE].

  44. J. Pumplin, A. Belyaev, J. Huston, D. Stump and W. Tung, Parton distributions and the strong coupling: CTEQ6AB PDFs, JHEP 02 (2006) 032 [hep-ph/0512167] [INSPIRE].

    Article  ADS  Google Scholar 

  45. W. Bernreuther, Top quark physics at the LHC, J. Phys. G 35 (2008) 083001 [arXiv:0805.1333] [INSPIRE].

    ADS  Google Scholar 

  46. F. Hubaut, E. Monnier, P. Pralavorio, K. Smolek and V. Simak, ATLAS sensitivity to top quark and W boson polarization in \( t\overline t \) events, Eur. Phys. J. C 44S2 (2005) 13 [hep-ex/0508061] [INSPIRE].

    Article  Google Scholar 

  47. J. Aguilar-Saavedra, J. Carvalho, N.F. Castro, A. Onofre and F. Veloso, ATLAS sensitivity to Wtb anomalous couplings in top quark decays, Eur. Phys. J. C 53 (2008) 689 [arXiv:0705.3041] [INSPIRE].

    Article  ADS  Google Scholar 

  48. J. Aguilar-Saavedra, Single top quark production at LHC with anomalous Wtb couplings, Nucl. Phys. B 804 (2008) 160 [arXiv:0803.3810] [INSPIRE].

    Article  ADS  Google Scholar 

  49. J. Aguilar-Saavedra and J. Bernabeu, W polarisation beyond helicity fractions in top quark decays, Nucl. Phys. B 840 (2010) 349 [arXiv:1005.5382] [INSPIRE].

    Article  ADS  Google Scholar 

  50. M.M. Najafabadi, Probing of Wtb Anomalous Couplings via the tW Channel of Single Top Production, JHEP 03 (2008) 024 [arXiv:0801.1939] [INSPIRE].

    Article  ADS  Google Scholar 

  51. A. Lucotte, A. Lléres and D. Chevallier, ATLAS note ATL-PHYS-PUB-2007-005.

  52. S. Zhu, Next-to-leading order QCD corrections to bg → tW − at CERN large hadron collider, hep-ph/0109269 [INSPIRE].

  53. M. Beccaria et al., A Complete one-loop description of associated tW production at LHC and a search for possible genuine supersymmetric effects, Eur. Phys. J. C 53 (2008) 257 [arXiv:0705.3101] [INSPIRE].

    Article  ADS  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Theoretical Physics Division, Physical Research Laboratory, Navrangpura, Ahmedabad, 380 009, India

    Saurabh D. Rindani & Pankaj Sharma

Authors
  1. Saurabh D. Rindani
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Pankaj Sharma
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Pankaj Sharma.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Rindani, S.D., Sharma, P. Probing anomalous tbW couplings in single-top production using top polarization at the Large Hadron Collider. J. High Energ. Phys. 2011, 82 (2011). https://doi.org/10.1007/JHEP11(2011)082

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1007/JHEP11(2011)082

Keywords

Search

Navigation