Polarization of top quark as a probe of its chromomagnetic and chromoelectric couplings in tW production at the Large Hadron Collider

2015/07/31 by Saurabh D. Rindani, Pankaj Sharma, A. W. Thomas +1
Physics and Astronomy · #Collider #Hadron #High-Energy Particle Collisions Research #Large Hadron Collider #Nuclear physics #Particle physics #Particle physics theoretical and experimental studies #Physics #Polarization (electrochemistry) #Quantum Chromodynamics and Particle Interactions #Quark #Top quark #hep-ph

paper · pdf · doi:10.1007/jhep10(2015)180

published as JHEP10 (2015) 180 · 25 pages, 13 figures, 2 tables. Matches the Published Version. arXiv admin note: text overlap with arXiv:1211.4075, arXiv:1107.2597

openalex publication_date 2015/10/01 · arxiv created 2015/10/28 · arxiv updated 2015/10/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

We study the sensitivity of the Large Hadron Collider (LHC) to top quark chromomagnetic (CMDM) and chromoelectric (CEDM) dipole moments and W tb effective couplings in single-top production in association with a W − boson, followed by semileptonic decay of the top. The W t single-top production mode helps to isolate the anomalous ttg and W tb couplings, in contrast to top-pair production and other single-top production modes, where other new-physics effects can also contribute. We calculate the top polarization and the effects of these anomalous couplings on it at two centre-of-mass (cm) energies, 8 TeV and 14 TeV. As a measure of top polarization, we look at decay-lepton angular distributions in the laboratory frame, without requiring reconstruction of the rest frame of the top, and study the effect of the anomalous couplings on these distributions. We construct certain asymmetries to study the sensitivity of these distributions to top-quark couplings. We determine individual limits on the dominant couplings, viz., the real part of the CMDM Reρ 2, the imaginary part of the CEDM Imρ 3, and the real part of the tensor W tb coupling Ref2R, which may be obtained by utilizing these asymmetries at the LHC. We also obtain simultaneous limits on pairs of these couplings taking two couplings to be non-zero at a time.

Citations

• Probing chromomagnetic and chromoelectric couplings of the top quark using its polarization in pair production at hadron colliders
• Probing anomalous tbW couplings in single-top production using top polarization at the Large Hadron Collider
• New features of FORM
• Combination of CDF and DO results on the mass of the top quark using up to 5.8~fb-1 of data
• Top-quark production in hadron-hadron collisions and anomalous top-quark–gluon couplings
• A New Decoupling Theorem in Top-Quark Physics
• Top-quark physics at the LHC
• Longitudinal top polarization as a probe of a possible origin of forward–backward asymmetry of the top quark at the Tevatron
• Measurement of the t-channel single-top-quark production cross section and of the |V tb| CKM matrix element in pp collisions at √(s) = 8 TeV
• Lepton distribution as a probe of new physics in production and decay of thetquark and its polarization
• Measuring effective electroweak couplings in single top quark production at the CERN LHC
• tW−mode of single top quark production
• Longitudinal top polarisation measurement and anomalous Wtb coupling
• Top quark physics at the LHC