Single Top Physics at Hadron Colliders

The production of top quark in electroweak processes was first observed in 2010 at the Tevatron. Since then it has been carefully studied at both LHC and Tevatron. Single top production proceeds through different channels and allows a direct determination of Cabibbo-Kobayashi-Maskawa matrix element $|V_{tb}|$. We will present the current status of searches and observation and discuss the results obtained so far and perspectives at hadron machines.Comment: Invited Report, to appear in Proceedings of Hadron Collider Physics 201

A Review of Recent Results from the Tevatron

The D0 and CDF experiments have been taking data at the Run 2 of the Tevatron Collider since 2001. We present a selection of recent results, most of them obtained with an integrated luminosity of $\simeq$ 1 fb$^{-1}$. I will describe the most important facets of the physics programme and detail some results. Recent direct limits on standard model Higgs obtained at the Tevatron, and their their prospects will be also reviewed.Comment: for the CDF and D0 Collaboration, DIS 07 Proceeding

Search for New Physics at Colliders

In this paper I present the most recent results of the ongoing searches, mainly from Tevatron Collider experiments, for new physics beyond the Standard Model. While no signal has been seen so far, many analyses are reaching the point in which either a discovery will take place or strong limit on currently popular theories will be set.Comment: To appear in Proceedings of PIC0

The Gravity of the Classical Klein-Gordon field

The work shows that the evolution of the field of the free Klein-Gordon equation (KGE), in the hydrodynamic representation, can be represented by the motion of a mass density subject to the Bohm-type quantum potential, whose equation can be derived by a minimum action principle. Once the quantum hydrodynamic motion equations have been covariantly extended to the curved space-time, the gravity equation (GE), determining the geometry of the space-time, is obtained by minimizing the overall action comprehending the gravitational field. The derived Einstein-like gravity for the KGE field shows an energy-impulse tensor density (EITD) that is a function of the field with the spontaneous emergence of the cosmological pressure tensor density (CPTD) that in the classical limit leads to the cosmological constant(CC). The energy-impulse tensor of the theory shows analogies with the modified Brans-Dick gravity with an effective gravity constant G divided by the field squared. Even if the classical cosmological constant is set to zero, the model shows the emergence of a theory-derived quantum CPTD that, in principle, allows to have a stable quantum vacuum (out of the collapsed branched polymer phase) without postulating a non-zero classical CC. In the classical macroscopic limit, the gravity equation of the KGE field leads to the Einstein equation. Moreover, if the boson field of the photon is considered, the EITD correctly leads to its electromagnetic energy-impulse tensor density. The outputs of the theory show that the expectation value of the CPTD is independent by the zero-point vacuum energy density and that it tends to zero as the space-time approaches to the flat vacuum, leading to an overall cosmological effect on the motion of the galaxies that may possibly be compatible with the astronomical observations.Comment: Published paper www.mdpi.com/journal/symmetr

Total Domishold Graphs: a Generalization of Threshold Graphs, with Connections to Threshold Hypergraphs

A total dominating set in a graph is a set of vertices such that every vertex of the graph has a neighbor in the set. We introduce and study graphs that admit non-negative real weights associated to their vertices such that a set of vertices is a total dominating set if and only if the sum of the corresponding weights exceeds a certain threshold. We show that these graphs, which we call total domishold graphs, form a non-hereditary class of graphs properly containing the classes of threshold graphs and the complements of domishold graphs, and are closely related to threshold Boolean functions and threshold hypergraphs. We present a polynomial time recognition algorithm of total domishold graphs, and characterize graphs in which the above property holds in a hereditary sense. Our characterization is obtained by studying a new family of hypergraphs, defined similarly as the Sperner hypergraphs, which may be of independent interest.Comment: 19 pages, 1 figur

ElectroWeak Symmetry Breaking in Tevatron Run II

The Tevatron Run II will provide CDF and D0 with a large dataset of ppbar interactions collected at sqrt(s)=2 TeV. We discuss the opportunity for the two experiments to improve the understanding of electrowek and top physics in the first years of data taking (Run IIa,2fb-1) in view of the upgrades of the detectors. We also discuss the prospectives for a Higgs discovery at the Tevatron in view of the Run IIb data taking period which will deliver an additional of about 13fb-1 to each experimentComment: 5 pages, 4+1 figure, to appear in proceedings of the EPS HEP 2001 Conference held in Budapest. To appear in JHEP Proceeding