This paper describes the physics case for a new fixed target facility at CERN SPS. The SHiP (search for hidden particles) experiment is intended to hunt for new physics in the largely unexplored domain of very weakly interacting particles with masses below the Fermi scale, inaccessible to the LHC experiments, and to study tau neutrino physics. The same proton beam setup can be used later to look for decays of tau-leptons with lepton flavour number non-conservation, [Formula: see text] and to search for weakly-interacting sub-GeV dark matter candidates. We discuss the evidence for physics beyond the standard model and describe interactions between new particles and four different portals-scalars, vectors, fermions or axion-like particles. We discuss motivations for different models, manifesting themselves via these interactions, and how they can be probed with the SHiP experiment and present several case studies. The prospects to search for relatively light SUSY and composite particles at SHiP are also discussed. We demonstrate that the SHiP experiment has a unique potential to discover new physics and can directly probe a number of solutions of beyond the standard model puzzles, such as neutrino masses, baryon asymmetry of the Universe, dark matter, and inflation.

We update the theoretical predictions for direct Upsilon(nS) hadroproduction in the framework of nonrelativistic QCD. We show that the next-to-leading order corrections in alpha(S) to the color-singlet transition significantly raise the differential cross section at high p(T) and substantially affect the polarization of the Upsilon. Motivated by the remaining gap between the next-to-leading order yield and the cross-section measurements at the Fermilab Tevatron, we evaluate the leading part of the alpha(S)(5) contributions, namely, those coming from Upsilon(nS) associated with three light partons. The differential color-singlet cross section at alpha(S)(5) is in substantial agreement with the data, so that there is no evidence for the need of color-octet contributions. Furthermore, we find that the polarization of the Upsilon(nS) is longitudinal. We also present our predictions for Upsilon(nS) production at the LHC.

We calculate the cross section for hadroproduction of a pair of heavy quarks in a 3 S1 color-singlet state at next-to-leading order in QCD. This corresponds to the leading contribution in the NRQCD expansion for J/ψ and Υ production. The higher-order corrections have a large impact on the pT distributions, enhancing the production at high pT both at the Tevatron and at the LHC. The total decay rate of a 3 S1 into hadrons at NLO is also computed, confirming for the first time the result obtained by Mackenzie and Lepage in 1981.PACS numbers: 12.38.Bx,13.25.Gv 1. Charmonium and bottomonium states are certainly among the most interesting systems to test our understanding of the strong interactions, both at the perturbative and non-perturbative level. More than thirty years after the discovery of the first charm-anticharm resonance, the J/ψ, the study of their properties, including production and decay mechanisms, is still the subject of considerable interest [1].From the theoretical point of view, a rigorous framework, based on the use of non-relativistic QCD (NRQCD) [2], has been introduced that allows consistent theoretical predictions to be made and to be systematically improved. However, despite theoretical developments and successes, not all the predictions of the NRQCD factorization approach have been firmly established. Recent measurements in e + e − collisions have shown that production rates for single and double charmonium production are in general much larger than those predicted by leading order calculations [3]. Measurements at the Tevatron in proton-antiproton collisions are not fully compatible with those obtained at HERA in electron-proton collisions [4] and in fixed-target experiments [5], suggesting the possibility that charmonium might be too light for the NRQCD factorization and/or scaling rules to work. In this context, a real challenge is offered by measurements of the J/ψ polarization at the Tevatron. NRQCD predicts a sizeable transverse polarization for J/ψ 's at high-p T , in contrast with the latest data that now clearly indicate that J/ψ's are not transversely polarized [6].In view of such a puzzling scenario, it is worth to re-examine in detail the theoretical predictions and try to systematically improve on them. In this Letter we report on the calculation of the next-to-leading order correction to the hadroproduction of a pair of heavy quarks in a color-singlet 3 S 1 state. This is the leading term in the NRQCD expansion for a J/ψ or a Υ and it is equivalent to the "color-singlet model" approximation. This model assumes that the nonperturbative dynamics leaves unchanged the quantum numbers of the perturbative quark-antiquark pair, which are the same as those of the physical bound state. It is curious to note that the analogous corrections to the hadronic decay width of a colorsinglet 3 S 1 state, which involve exactly the same diagrams, have been available for a long time [7] and play an important role in the extraction of α S from Υ decays [8]. Our calculation for the inclusive decay r...

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.

We present the program package GOSAM which is designed for the automated calculation of one-loop amplitudes for multi-particle processes in renormalisable quantum field theories. The amplitudes, which are generated in terms of Feynman diagrams, can be reduced using either D-dimensional integrand-level decomposition or tensor reduction. GOSAM can be used to calculate one-loop QCD and/or electroweak corrections to Standard Model processes and offers the flexibility to link model files for theories Beyond the Standard Model. A standard interface to programs calculating real radiation is also implemented. We demonstrate the flexibility of the program by presenting examples of processes with up to six external legs attached to the loop.