Measuring effective electroweak couplings in single top production at the LHC

Abstract

We study the mechanism of single top production at the LHC in the framework of an effective electroweak Lagrangian, analyzing the sensitivity of different observables to the magnitude of the effective couplings that parametrize new physics beyond the Standard Model. The observables relevant to the distinction between left and right effective couplings involve in practice the measurement of the spin of the top and this can be achieved only indirectly by measuring the angular distribution of its decay products. We show that the presence of effective right-handed couplings implies that the top is not in a pure spin state. A unique spin basis is singled out which allows one to connect top decay products angular distribution with the polarized top differential cross section. We present a complete analytical expression of the differential polarized cross section of the relevant perturbative subprocess including general effective couplings. The mass of the bottom quark, which actually turns out to be more relevant than naively expected, is retained. Finally we analyze different aspects the total cross section relevant to the measurement of new physics through the effective couplings. The above analysis also applies to anti-top production in a straightforward way.

38 pages, 17 figures

References in corpus (2)

• Complete angular analysis of polarized top decay at O(alpha_s)
• The Z ->anti-b b decay asymmetry: lose-lose for the Standard Model

Cited by in corpus (27)

• The fully differential single-top-quark cross section in next-to-leading order QCD
• Understanding single-top-quark production and jets at hadron colliders
• W polarisation beyond helicity fractions in top quark decays
• Single Top Quark Production and Decay at Next-to-leading Order in Hadron Collision
• Collider aspects of flavour physics at high Q
• Next-to-Leading Order Corrections to Single Top Quark Production and Decay at the Tevatron: 1. s-channel Process
• ATLAS sensitivity to top quark and W boson polarization in $t\bar{t}$ events
• A General Analysis of Wtb anomalous Couplings
• Precise determination of the Wtb couplings at LHC
• Probing top charged-Higgs production using top polarization at the Large Hadron Collider
• New directions for top quark polarization in the $t$-channel process
• Next-to-leading order QCD corrections to s-channel single top quark production and decay at the LHC
• Dimension six FCNC operators and top production at the LHC
• Flavour changing strong interaction effects on top quark physics at the LHC
• Combined effects of strong and electroweak FCNC effective operators in top quark physics at the LHC
• Model Independent Constraints Among the Wtb, Zbb, and Ztt Couplings
• Strong flavour changing effective operator contributions to single top quark production
• A study of top polarization in single-top production at the LHC
• Search for new physics via single top production at TeV energy $e\gamma$ colliders
• Polarization of top quark as a probe of its chromomagnetic and chromoelectric couplings in $tW$ production at the Large Hadron Collider
• CP violation in tbW couplings at the LHC
• Contributions from dimension six strong flavor changing operators to top anti-top, top plus gauge boson, and top plus Higgs boson production at the LHC
• Full analysis of general non-standard tbW couplings
• Semileptonic decays of polarised top quarks: V + A admixture and QCD corrections
• NNLO QCD corrections to the polarized top quark decay $t(\uparrow )\to X_b+W^{+}$
• Experimental Studies of Top Quark Production
• QCD corrections to single top quark production in electron photon interactions