121849618
Electromagnetic properties of states in Cu-63 through the inelastic scattering of protons
28536320
pn to d and alpha pn to alpha d emission ratios in heavy-ion-induced reactions.
The competition between pn and d as well as between ..cap alpha..pn and ..cap alpha..d evaporation leading to the production of the same residual nuclei has been measured for nine and five heavy-ion-induced nuclear reactions, respectively, each at several bombarding energies. The deduced sigma/sub pn//sigma/sub d/ ratios have been found to be in very good agreement with the predictions of a previously extracted empirical equation. The ratios sigma/sub ..cap alpha..//sub pn//sigma/sub ..cap alpha..//sub d/ do not seem to depend on either the interacting system or the maximum excitation energy available to the residual nucleus.
118327429
Au-197(n,gamma) cross section in the resonance region
The (n,gamma) cross section of Au-197 has been measured at n_TOF in the resolved resonance region, up to 5 keV, with the aim of improving the accuracy in an energy range where it is not yet considered standard. The measurements were performed with two different experimental setup and detection techniques, the total energy method based on C6D6 detectors, and the total absorption calorimetry based on a 4 pi BaF2 array. By comparing the data collected with the two techniques, two accurate sets of neutron-capture yields have been obtained, which could be the basis for a new evaluation leading to an extended cross-section standard. Overall good agreement is found between the n_TOF results and evaluated cross sections, with some significant exceptions for small resonances. A few resonances not included in the existing databases have also been observed.
118374882
Top quark pair production in association with a Z-boson at NLO accuracy
We present predictions for the production cross section of t-quark pair production in association with a Z boson at the next-to-leading order (NLO) accuracy using matrix elements obtained from the HELAC-Oneloop package. We use the subtraction method for computing the radiative corrections as implemented in the POWHEG-Box, which was also used in several other computations of similar complexity.
118433589
NLO QCD calculations with HELAC-NLO
Achieving a precise description of multi-parton final states is crucial for many analyses at LHC. In this contribution we review the main features of the HELAC-NLO system for NLO QCD calculations. As a case study, NLO QCD corrections for t t ¯ + 2 jet production at LHC are illustrated and discussed.
2891581
HELAC - A MONTE CARLO GENERATOR FOR MULTI-JET PROCESSES
The status of the multi-purpose event generator HELAC is briefly presented. The aim of this tool is the full simulation of events within the Standard Model (SM) at current and future high energy experiments, in particular the LHC. Some results related to the production of multi-jet final states at the LHC are also discussed.
118355615
Hadronic top-quark pair production in association with two jets at Next-to-Leading Order QCD
We report on the calculation of the next-to-leading order QCD corrections to the production of t¯ pairs in association with two hard jets at the Fermilab TeVatron and CERN Large Hadron Collider. Results for the integrated and differential cross sections are given. The corrections with respect to leading order are negative and moderate. A study of the scale dependence of our NLO predictions indicates that the residual theoretical uncertainty, due to higher order corrections, is 21% for the TeVatron and 15% for the LHC. In case of the TeVatron, the forward-backward asymmetry of the top quark is calculated for the first time at next-to-leading order. With the inclusive selection of cuts, this asymmetry amounts to A t,LO = 10.3% at leading order and A t,NLO = 4.6% at next-to-leading order. All results presented in this paper have been obtained with the help of the Helac-Nlo package.
122064270
Jet cross sections probing possible quark substructure at hadron colliders
We calculate the two- and three-jet angular distributions in the presence of an effective contact interaction of two flavour-diagonal left-handed quark currents. Assuming five flavours of composite quarks, present data show that the compositeness scale Λc should be above ∼ 600 GeV. Forthcoming data from the Fermilab-Tevatron may soon push this bound up to Λc ⪆ 1500 GeV.