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The current uncertainty on the proton content (PDFs) affects the potential discovery of new physics at LHC. The vector boson production associated with an inclusive jet is one of the most interesting candidate to constraint this uncertainty over the whole LHC kinematic regime in the ATLAS experiment. In particular, the Standard Model process such as plus one jet production, described here in details, is a process of a particular interest not only for PDF’s study but for the Higgs and SUSY physics discovery.

I briefly review some tests of the Standard Model in the light of the improvements of the last year in experimental and theoretical electroweak physics. In particular I focus my attention on the new values of the masses of the boson and top quark and on the new theoretical computation of the two-loop electroweak corrections to sin.

The and bosons production cross sections at LHC will be huge: () 20 nb, () 2nb. Moreover the and production and decay processes have been measured with high accuracy in previous experiments. Thus the and bosons will play a key role during the first data taking at LHC allowing to test the detector performances and to tune the Monte Carlo generators. In fact, with only 1fb of integrated luminosity, the processes involving EW bosons will be used to calibrate Electromagnetic Calorimeters and to align Muon and Tracker Systems. With 10 fb of integrated luminosity, the study of and events will improve our knowledge of the Parton Distribution Functions (PDF) and it will provide a raw luminosity monitoring. In the following we will focus on these EW bosons studies achievable already at low luminosity. These analysis hold the key for all the future searches because they provide the way to control many of the main experimental and theoretical systematics at LHC.

The production of a high-transverse-momentum lepton pair, known as Drell-Yan (DY) process, plays an important role at hadron colliders, such as the Fermilab Tevatron and the CERN LHC, thanks to the large cross section and the clean signature of the final state, with at least one high-transverse-momentum lepton to trigger on. After the LEP and Tevatron precision measurement of the gauge boson masses, the DY processes represent standard candles which can be used for the detector calibration. The production of gauge bosons, in association with jets, is an important background to interesting physics channels, like the top quark pair production. The mass of the boson will be measured at the LHC from the transverse mass distribution, but also from the ratio (d/d)/(d/d), with a foreseen final uncertainty of Δ ≈ 15MeV []. The latter, combined with the improvement in the determination of the top quark mass (foreseen with an accuracy of 1–2GeV), will put more stringent bounds in all the precision tests of the Standard Model. The DY processes provide, both in neutral and charged current channels, stringent constraints on the density functions which describe the partonic content of the proton []. The important progress in the calculation of the QCD corrections has reduced at the per cent level the residual theoretical uncertainties which affect the DY cross sections; as a consequence, it has been proposed to use them as a luminosity monitor of the collider [,]. The large mass tail of the invariant mass distribution represents an important background to the search for new heavy gauge bosons [].

At hadron colliders, the strong production of pairs yelds large top quark samples, allowing detailed studies of many properties of top quark production and decay. However, the precise determination of the properties of the vertex, and the associated coupling strenghts, will more likely be obtained from measurements of the electroweak production of single top quarks. Single top quarks can be produced via three different reactions. These reactions are shown in Fig. 1 from left to right. The first two graphs, usually referred to as the 2 → 2 and 2 → 3 processes, respectively, both refer to the same physical -gluon fusion process. The second production mechanism (the third graph from the left), referred to as the process, is the direct production of a top quark and a boson. This process is immeasurably small at the Tevatron, but is predicted to have a sizeable cross-section (≈ 60–110 pb) at the LHC. The third reaction proceeds via production of an off-shell and will be called the * process.

Since its discovery at Tevatron in 1995, the top quark has been studied with an increasing level of precision by the CDF and D0 experiments. However most of the measurements are still statistically limited and larger top samples are needed to open a window on new physics.

A new collider, the Large Hadron Collider, under construction at CERN, will soon provide about 8 millions of top-antitop events in one year at low luminosity, giving a new opportunity for precision measurements of the top quark properties.

Prior to the precise top quark properties measurements, requiring detailed knowledge of the detector response and the understanding of the possible sources of systematic uncertainties, the top-antitop events will be used form the very early data taking period in commissioning phase, allowing the understanding of the detector response to different physics objects and a preliminary investigation of top quark mass measurement.

We summarize the status of QCD corrections for SM Higgs boson production at hadron colliders and briefly sketch the main search strategies at the LHC.

In this paper, a brief overview of the Standard Model Higgs boson discovery potential of the ATLAS [] and CMS [] experiments at the Large Hadron Collider (LHC) is given. A subset of the main search channels, and of the requirements they have posed to the design of the two experiments, will be described in more detail. The full discovery potential of the two experiments, together with the possibility they will have to assess the profile of an Higgs boson in case of its discovery, will be also described.

The presence of a heavy neutral gauge bosons ′, besides the , is foreseen in various non-SUSY models. There are no reliable theoretical predictions, however, of its mass scale. Current lower limits from LEP and the Tevatron on the ′ mass [] are 600–900GeV, depending on the model. LHC is going to be the first opportunity to search for ′ bosons in a mass range significantly larger than 1TeV: here we review a work on the process ′ → , for a work concerning ′ → we suggest the reading of [].

Over the past three decades the Standard Model (SM) of particle physics has been surprisingly successful. Although the precision of experimental tests improved by orders of magnitude no significant deviation from the SM predictions has been observed so far. Still, there are many questions that the Standard Model does not answer and problems it can not solve. Among the most important ones are the origin of the electro-weak symmetry breaking, hierarchy of scales, unification of fundamental forces and the nature of gravity. Recent cosmological observations indicates that the SM particles only account for 4% of the matter of the Universe. Many extensions of the SM (Beyond the Standard Model, BSM) have been proposed to make the theory more complete and solve some of the above puzzles. Some of these extension includes SuperSymmetry (SUSY), Grand Unification Theory (GUT) and Extra Dimensions. At CDF [] and D0 [] we search for evidence of such processes in proton-antiproton collisions at = 1980 GeV. The phenomenology of these models is very rich, although the cross sections for most of these exotic processes is often very small compared to those of SM processes at hadron colliders. It is then necessary to devise analysis strategies that would allow to disentagle the small interesting signals, often buried under heavy instrumental and SM background.