Related papers: Single top polarisation as a window to new physics
The top quark pairs produced at a polarized muon collider are in a (nearly) pure spin configuration. This result holds for all center-of-mass energies, and is insensitive to the next-to-leading order QCD radiative corrections. The decay…
A number of top-spin observables are computed within the Standard Model (SM), at next-to-leading order in the strong and weak gauge couplings for hadronic top-quark anti-quark (ttbar) production and decay at the LHC for center-of-mass…
We present a detailed investigation of the NLO polarization of the top quark in t t-bar production at a polarized linear e^+ e^- collider with longitudinally polarized beams. By appropiately tuning the polarization of the beams one can…
We study the effects of four-heavy-quark operators in the production of top quarks in the framework of the Standard Model Effective Field Theory (SMEFT) at the LHC. In particular, we compute for the first time the total contribution of the…
We summarise a recent study looking at top quark polarisation effects in charged Higgs boson production. Lab frame angular and energy observables relating to leptonic decays of top quarks are analysed, and corresponding asymmetry parameters…
We describe the latest results obtained by the CMS Collaboration on top quark spin and polarization properties. The top quark spin asymmetry is measured both targeting single-top quark production in the $t$-channel and single-top quark…
Effective field theories provide a model independent parametrization of the physics beyond the SM if the new degrees of freedom are heavy and complement thus the searches for resonances. In this talk, I will apply this method to the top…
We discuss heavy quark contributions to the neutrino-nucleon total cross section at very high energies, well above the real top production threshold. The top-bottom weak current is found to generate strong left-right asymmetry of…
A detailed evaluation is presented of production of heavy fermions (particularly ttbar quarks) by a vector current, in the region around threshold. This includes bound states as well as the region above threshold, to the same degree of…
We study the effect of multiple soft gluon radiation on the kinematical distributions of the $t$-channel single top quark production at the LHC. By applying the transverse momentum dependent factorization formalism, large logarithms (of the…
Recently, experimental collaborations have reported $\mathcal{O}(10)$ upper limits on the signal strength of four-top production at the LHC. Surprisingly, we find that the constraining power of four-top production on the $qqtt$ type of…
Double open-charm production is one of the most promising channels to disentangle single from double parton scattering (DPS) and study different properties of DPS. Several studies of the DPS contributions have been made. A missing…
Extensions of the Standard Model often predict new chiral interactions for top quark, which will contribute to top quark spin correlation and polarization in $t\bar{t}$ production at the LHC. In this work, under the constraints from the…
We study higher-order QCD corrections for the production of a top-antitop quark pair ($t{\bar t}$ production) at the Large Hadron Collider in the Standard Model Effective Field Theory. We consider effects of new physics parametrized by the…
We investigate the factorization and resummation of t-channel single top (antitop) quark production in the SM at both the Tevatron and the LHC in SCET. We find that the resummation effects decrease the NLO cross sections by about 3% at the…
Anomalies in recent LHCb, Belle and Babar measurements of $R_{D^{(*)}}$, and $R_{K^{(*)}}$ in $B$ decays may indicate the new physics beyond the Standard Model (SM). The leptoquarks ($LQ$) that couple to the $3^{\mathrm{rd}}$ generation…
The azimuthal angle dependence of quark spin polarization in the longitudinal beam direction of non-central relativistic heavy ion collisions is studied in the chiral kinetic approach. Contrary to the prediction from models based on the…
We investigate the single top quark production with the exchange of unparticles through high energy photon-photon collision $\gamma \gamma\to t \bar c$. The effects of unparticles on the scattering cross sections for different polarization…
Forward-backward asymmetries $A_{FB}^t$ and $A_{FB}^\ell$ are observed in the top quark $t$ rapidity distribution and in the rapidity distribution of charged leptons $\ell$ from top quark decay at the Tevatron proton-antiproton collider,…
We compute the imaginary part of the heavy quark contribution to the photon polarization tensor, i.e. the quarkonium spectral function in the vector channel, at next-to-leading order in thermal QCD. Matching our result, which is valid…