arXiv subjects

Francesco Tramontano

Publications and source records attributed to Francesco Tramontano.

40 records · Page 3Linked to original sources

arXiv2009

NLO predictions for t-channel production of single top and fourth generation quarks at hadron colliders

We present updated NLO predictions for the electroweak t-channel production of heavy quarks at the Tevatron and at the LHC. We consider production of single top and fourth generation t' starting from both 2 to 2 and 2 to 3 Born processes. Predictions for tb' and t'b' cross sections at NLO are also given for the first time. A thorough study of the theoretical uncertainties coming from parton distribution functions, renormalisation and factorisation scale dependence and heavy quark masses is performed.

hep-ph↗

arXiv2009

Next-to-leading-order predictions for t-channel single-top production at hadron colliders

We present the predictions at next-to-leading order (NLO) in the strong coupling for the single-top cross section in the t channel at the Tevatron and the LHC. Our calculation starts from the 2 -> 3 Born amplitude g q -> t bbar q', keeping the b-quark mass non-zero. A comparison is performed with a traditional NLO calculation of this channel based on the 2 -> 2 Born process with a bottom quark in the initial state. In particular, the effect of using kinematic approximations and resumming logarithms of the form log(Q^2/m_b^2) in the 2 -> 2 process is assessed. Our results show that the 2 -> 3 calculation is very well behaved and in substantial agreement with the predictions based on the 2 -> 2 process.

hep-ph↗

arXiv2005

Next-to-leading order corrections to Wt production and decay

We present the results of a next-to-leading order calculation of Wt production, including the decays of both the top quark and the W boson. The effects of radiation in the decay of the top quark are also included. The separation of diagrams which appear in the real corrections, into singly- and doubly-resonant contributions, is performed using a b-jet veto which is motivated by the use of the bottom quark distribution function. We find that, for a choice of scale which is suitable for this approach, the QCD corrections are very mild and only change the cross section by up to 10% at the LHC, depending on the severity of the b-jet veto. When further cuts are applied, applicable for a Higgs boson search in the H->WW channel, we find that the radiative effects greatly decrease the number of background events expected from this process. In addition, the shapes of relevant distributions can be significantly changed at next-to-leading order.

hep-ph↗

arXiv2004

Single top production and decay at next-to-leading order

We present the results of a next-to-leading order analysis of single top production including the decay of the top quark. Radiative effects are included both in the production and decay stages, using a general subtraction method. This calculation gives a good treatment of the jet activity associated with single top production. We perform an analysis of the single top search at the Tevatron, including a consideration of the main backgrounds, many of which are also calculated at next-to-leading order.

hep-ph↗