Top differential cross section measurements (Tevatron)

Differential cross sections in the top quark sector measured at the Fermilab Tevatron collider are presented. CDF used 2.7 fb$^{-1}$ of data and measured the differential cross section as a function of the invariant mass of the $t\bar{t}$ system. The measurement shows good agreement with the standard model and furthermore is used to derive limits on the ratio $\kappa /M_{Pl}$ for gravitons which decay to top quarks in the Randall-Sundrum model. D0 used 1.0 fb$^{-1} of data to measure the differential cross section as a function of the transverse momentum of the top quark. The measurement shows a good agreement to the higher order perturbative QCD prediction and various predictions based on various Monte-Carlo generators.Comment: To appear in the Proceedings of TOP2011, 4th International Workshop on Top Quark Physics, Spai

Inclusive top pair production at Tevatron and LHC in electron/muon final states

Recent measurements of the inclusive top pair production at the Tevatron and LHC collider in the electron/muon final states are discussed. Measurements at the Tevatron use up to 9.7 /fb of data, and at the LHC up to 4.9 /fb of data at $\sqrt{s}=7$ TeV and up to 20.3 /fb of data at $\sqrt{s}=8$ TeV. For the experiments at both colliders these corresponds to the full data sets at the given center-of-mass energies. Overall results are in agreement between the experiments at the Tevatron and between the experiments at the LHC. All measurements are in agreement with recent theory calculations at NNLO QCD. Individual LHC measurements are challenging the precision of the theory calculations.Comment: Proceedings for the 6th International Workshop on Top Quark Physics. 14-19 September 2013, Durbach, German

Simultaneous universality

In this paper, the notion of simultaneous universality is introduced, concerning operators having orbits that simultaneously approximate any given vector. This notion is related to the well known concepts of universality and disjoint universality. Several criteria are provided, and several applications to specific operators or sequences of operators are performed, mainly in the setting of sequence spaces or spaces of holomorphic functions.Plan Andaluz de Investigación (Junta de Andalucía)Ministerio de Economía y CompetitividadDeutsche Forschungsgemeinschaf

Multilevel Network Games

We consider a multilevel network game, where nodes can improve their communication costs by connecting to a high-speed network. The $n$ nodes are connected by a static network and each node can decide individually to become a gateway to the high-speed network. The goal of a node $v$ is to minimize its private costs, i.e., the sum (SUM-game) or maximum (MAX-game) of communication distances from $v$ to all other nodes plus a fixed price $\alpha > 0$ if it decides to be a gateway. Between gateways the communication distance is $0$, and gateways also improve other nodes' distances by behaving as shortcuts. For the SUM-game, we show that for $\alpha \leq n-1$, the price of anarchy is $\Theta(n/\sqrt{\alpha})$ and in this range equilibria always exist. In range $\alpha \in (n-1,n(n-1))$ the price of anarchy is $\Theta(\sqrt{\alpha})$, and for $\alpha \geq n(n-1)$ it is constant. For the MAX-game, we show that the price of anarchy is either $\Theta(1 + n/\sqrt{\alpha})$, for $\alpha\geq 1$, or else $1$. Given a graph with girth of at least $4\alpha$, equilibria always exist. Concerning the dynamics, both the SUM-game and the MAX-game are not potential games. For the SUM-game, we even show that it is not weakly acyclic.Comment: An extended abstract of this paper has been accepted for publication in the proceedings of the 10th International Conference on Web and Internet Economics (WINE

Track clustering with a quantum annealer for primary vertex reconstruction at hadron colliders

Clustering of charged particle tracks along the beam axis is the first step in reconstructing the positions of hadronic interactions, also known as primary vertices, at hadron collider experiments. We use a 2036 qubit D-Wave quantum annealer to perform track clustering in a limited capacity on artificial events where the positions of primary vertices and tracks resemble those measured by the Compact Muon Solenoid experiment at the Large Hadron Collider. The algorithm, which is not a classical-quantum hybrid but relies entirely on quantum annealing, is tested on a variety of event topologies from 2 primary vertices and 10 tracks up to 5 primary vertices and 15 tracks. It is benchmarked against simulated annealing executed on a commercial CPU constrained to the same processor time per anneal as time in the physical annealer, and performance is found to be comparable for small numbers of vertices with an intriguing advantage noted for 2 vertices and 16 tracks