Related papers: New physics in ttbar spin correlations at the Teva…
We investigate the feasibility of probing anomalous top-quark couplings of $Wtb$, $Z t \bar{t}$, and $\gamma t \bar{t}$ in terms of an effective Lagrangian with dimension-six operators at future $e^+e^-$ linear colliders with a c. m. energy…
The capability of the LHC to study the electromagnetic dipole moments of the top quark is discussed. In particular, the process $pp\to p\gamma\gamma p\to pt\bar{t}p$, which is supposed to be tagged by the forward/backward detectors at the…
This paper presents a search for a new heavy particle produced in association with a top or antitop quark. Two models in which the new heavy particle is a color singlet or a color triplet are considered, decaying respectively to tbarq or…
We consider the recent measurement of the top quark forward-backward asymmetry at the Fermilab Tevatron, which shows a discrepancy of slightly more than 2$\sigma$ compared to the SM prediction. We find that $t$-channel exchange of a color…
Top-antitop pairs produced in the decay of a new heavy resonance will exhibit spin correlations that contain valuable coupling information. When the tops decay, these correlations imprint themselves on the angular patterns of the final…
We exactely calculate the inclusive transverse momentum (kt) distributions and the 2-particle momentum correlations in high energy hadronic jets at the Modified Leading Logarithmic Approximation (MLLA) of QCD (Quantum Chromodynamics). We…
We describe the off-diagonal spin basis for observing angular correlations in top quark pair production events at the Fermilab Tevatron. For events initiated by quark-antiquark annihilation, the top and antitop quark spins are 100%…
We report on a search for compositeness in ee+gamma events and a search for gauge-mediated supersymmetry in gamma+gamma+met events. We also report on two signature-based searches for anomalous production of gamma + gamma + X (where X=e, mu,…
Theoretical issues are discussed for the measurement of the top-mass using jets, including perturbative and non-perturbative effects that relate experimental observables to the Lagrangian mass, and appropriate choices for mass schemes. Full…
A search for new physics is performed using events with isolated same-sign leptons and at least two bottom-quark jets in the final state. Results are based on a sample of proton-proton collisions collected at a center-of-mass energy of 8…
We investigate existing and future hadron-collider constraints on the top dipole chromomagnetic and chromoelectric moments, two quantities that are expected to be modified in the presence of new physics. We focus first on recent…
A model-independent search for the production of heavy resonances decaying into top-antitop quark pairs is presented. The search is based on events containing one lepton (muon or electron) and at least two jets selected from data samples…
Differential cross-sections for top-quark pair production, inclusively and in association with jets, are measured in $pp$ collisions at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC using an integrated luminosity of…
Top quark pairs are produced with strongly correlated spins in the partonic reactions $q\bar{q}\to t\bar{t}$ and $gg\to t\bar{t}$. A complete description of these effects in terms of the spin density matrix of the $t\bar{t}$ system in…
We present a measurement of the top-quark mass in events containing two leptons (electrons or muons) with a large transverse momentum, two or more energetic jets, and a transverse-momentum imbalance. We use the full proton-antiproton…
There exist several recent studies of the top-quark CEDM in the context of searching for CP violating signals in top-quark pair production at the LHC. Most of these studies constrain the CEDM either from deviations in the top-pair cross…
We study the quantum properties of top quark pairs in lepton colliders with unpolarised beams, including spin correlations, entanglement, and violation of Bell inequalities. We present analytical results in the SM and in the SMEFT and…
I discuss the production of leptoquarks in $p\bar{p}$ collisions at the Fermilab Tevatron. Evaluated on the basis of a recent next-to-leading order calculation, the combined D0 and CDF leptoquark searches lead to a parameter-free lower mass…
We investigate the angular distribution of the lepton pair in the process $p \bar{p} \rightarrow \gamma^{\ast} + X \rightarrow \ell^+\ell^- + X$, where the virtual photon is produced at high transverse momentum. The angular distribution of…
In this report a new search for a narrow-width heavy resonance decaying into top quark pairs (X -> ttbar) in ppbar collisions at sqrt(s)=1.96 TeV has been performed using data collected by the D0 detector at the Fermilab Tevatron collider.…