相关论文: Is Vtb=1 ?
Verifying $V_{tb} \simeq 1$ is critical to test the three generation assumption of the Standard Model. So far our best knowledge of $V_{tb}$ is inferred either from the $3\times 3$ unitarity of CKM matrix or from single top-quark…
The measurement of the single top-quark production cross section in hadron collisions at the Tevatron and the LHC can be used to determine the absolute value of the CKM matrix element V_tb without assuming the unitarity of the CKM matrix.…
After many years searching for electroweak production of top quarks, the Tevatron collider experiments have now moved from obtaining first evidence for single top quark production to an impressive array of measurements that test the…
The CKM matrix elements $V_{td}$, $V_{ts}$ and $V_{tb}$, while notoriously hard to measure directly in experiment, can be determined to great precision within the Standard Model (SM) with a minimal set of observables due to unitarity of…
The $Wtb$ vertex structure and the search for new anomalous couplings is studied using top quark measurements obtained at the LHC, for a centre-of-mass energy of 8 TeV. By combining the latest and most precise results on the single top…
I present measurements by the CDF collaboration of the Standard Model three generation CKM matrix element Vtb and of a special case extension with additional assumptions, using current Tevatron ttbar data. I then show how we can…
Recent developments in models with warped extra dimensions have opened new possibilities for vector-like quark studies at hadron colliders. These new vector-like quarks can mix sizably with light Standard Model quarks without violating low…
The Tevatron experiments D0 and CDF have found evidence for single top quark production, based on datasets between 0.9fb-1 and 2.2fb^-1. Several different multivariate techniques are used to extract the single top quark signal out of the…
Single top quark production cross sections at hadron colliders are traditionally used to extract the modulus of the $V_{tb}$ element of the Cabibbo-Kobayashi-Maskawa matrix under the following assumption: $|V_{tb}| \gg |V_{td}|, |V_{ts}|$.…
The prospects of single top quark physics at colliders of the TeV energy scale are discussed. Single top quark study allows a direct measurement of the $Wtb$ vertex and a precise probing physics beyond the Standard Model in various…
The latest results on top quark physics, namely single top quark production cross sections, $W$-boson helicity and asymmetry measurements are used to probe the Lorentz structure of the $Wtb$ vertex. The increase of sensitivity to new…
Single top production processes are usually regarded as the ones in which V_tb can be directly measured at hadron colliders. We show that the analysis of the single top rapidity distribution in t-channel and tW production can also set…
Unitarity along with precision measurements of sin2\beta, V_{us} and V_{cb} allows one to find a lower bound V_{ub}\geq 0.0035 which, on using the recently measured angle \alpha of the unitarity triangle, translates to V_{ub}= 0.0035\pm…
We point out that hints of deviations from unitarity in the first row of the CKM matrix may be explained by the presence of a single vector-like top. We study how the stringent experimental constraints arising from CP Violation in the kaon…
We present the results obtained by the CDF and D0 collaborations on the extraction of the CKM matrix element Vtb, the $W$ helicity measurements, and the constraints obtained on the $Wtb$ vertex.
Single top quark production via the electroweak interaction was observed by the D0 and CDF collaborations at the Tevatron proton-antiproton collider at Fermilab. Multivariate analysis techniques are employed to extract the small single top…
The prospects of measuring the CKM matrix elements |V_tq| with top quarks decays at the LHC are discussed here, with the top quarks produced in the processes pp \rightarrow ttbarX and pp \rightarrow t/tbarX, and the subsequent decays t…
We present new direct constraints on a general $Wtb$ interaction using data corresponding to an integrated luminosity of 5.4 fb$^{-1}$ collected by the D0 detector at the Tevatron $p\bar{p}$ collider. The standard model provides a purely…
The latest and most precise top quark measurements at the LHC and Tevatron are used to establish new limits on the $Wtb$ vertex. Recent results on the measurements of the $W$-boson helicity fractions and single top quark production cross…
New vector-like quarks can have sizable couplings to first generation quarks without conflicting with current experimental constraints. The coupling with valence quarks and unique kinematics make single production the optimal discovery…