16443896
On the classification of type D space–times
We give a classification of the type D space–times based on the invariant differential properties of the Weyl principal structure. Our classification is established using tensorial invariants of the Weyl tensor and, consequently, besides its intrinsic nature, it is valid for the whole set of the type D metrics and it applies on both, vacuum and nonvacuum solutions. We consider the Cotton-zero type D metrics and we study the classes that are compatible with this condition. The subfamily of space–times with constant argument of the Weyl eigenvalue is analyzed in more detail by offering a canonical expression for the metric tensor and by giving a generalization of some results about the nonexistence of purely magnetic solutions. The usefulness of these results is illustrated in characterizing and classifying a family of Einstein–Maxwell solutions. Our approach permits us to give intrinsic and explicit conditions that label every metric, obtaining in this way an operational algorithm to detect them. In partic...
119404232
On the space-times admitting two shear-free geodesic null congruences
We analyze the space-times admitting two shear-free geodesic null congruences. The integrability conditions are presented in a plain tensorial way as equations on the volume element U of the time-like 2-plane that these directions define. From these we easily deduce significant consequences. We obtain explicit expressions for the Ricci and Weyl tensors in terms of U and its first and second order covariant derivatives. We study the different compatible Petrov-Bel types and give the necessary and sufficient conditions that characterize every type in terms of U. The type D case is analyzed in detail and we show that every type D space-time admitting a 2 + 2 conformal Killing tensor also admits a conformal Killing-Yano tensor.
118521043
An intrinsic characterization of spherically symmetric spacetimes
We give the necessary and sufficient (local) conditions for a metric tensor to be a nonconformally flat spherically symmetric solution. These conditions exclusively involve explicit concomitants of the Riemann tensor. As a direct application we obtain the ideal labeling of the Schwarzschild, Reissner–Nordstrom and Lemaitre–Tolman–Bondi solutions.
14680880
An intrinsic characterization of the Kerr metric
We give the necessary and sufficient (local) conditions for a metric tensor to be the Kerr solution. These conditions exclusively involve explicit concomitants of the Riemann tensor.
119234596
On the super-energy radiative gravitational fields
We extend our recent analysis (Ferrando J J and Saez J A 2012 Class. Quantum Grav. 29 075012) on the Bel radiative gravitational fields to the super-energy radiative gravitational fields defined by Garcia-Parrado (2008 Class. Quantum Grav. 25 015006). We give an intrinsic characterization of the new radiative fields and consider some distinguished classes of both radiative and non-radiative fields. Several super-energy inequalities are improved.
119760521
On the intrinsic labeling of space‐times: a characterization of the Kerr solution
The interest of obtaining an intrinsic (depending solely on the metric tensor) and fully explicit characterization of a space‐time is pointed out. We give the necessary and sufficient (local) conditions for a metric tensor to be the Kerr solution. These conditions exclusively involve concomitants of the Weyl tensor.
15330351
Subjet distributions in deep inelastic scattering at HERA
Subjet distributions were measured in neutral current deep inelastic ep scattering with the ZEUS detector at HERA using an integrated luminosity of 81.7 pb−1. Jets were identified using the kT cluster algorithm in the laboratory frame. Subjets were defined as jet-like substructures identified by a reapplication of the cluster algorithm at a smaller value of the resolution parameter $y_{\rm cut}$. Measurements of subjet distributions for jets with exactly two subjets for $y_{\rm cut}=0.05$ are presented as functions of observables sensitive to the pattern of parton radiation and to the colour coherence between the initial and final states. Perturbative QCD predictions give an adequate description of the data.
10815425
Boosted objects: a probe of beyond the standard model physics
We present the report of the hadronic working group of the BOOST2010 workshop held at the University of Oxford in June 2010. The first part contains a review of the potential of hadronic decays of highly boosted particles as an aid for discovery at the LHC and a discussion of the status of tools developed to meet the challenge of reconstructing and isolating these topologies. In the second part, we present new results comparing the performance of jet grooming techniques and top tagging algorithms on a common set of benchmark channels. We also study the sensitivity of jet substructure observables to the uncertainties in Monte Carlo predictions.
59418732
HERA signature-based searches I: events with isolated leptons and missing transverse momentum at HERA
Recent results of searches for events containing isolated leptons and missing transverse momentum at HERA are presented. Searches in this final state have yielded notable excesses over Standard Model expectations in the past. Searches for isolated leptons in channels corresponding to all three generations of leptons over the full HERA running period are now available. The combined H1+ZEUS results for searches for electrons and muons are compatible with the Standard Model.
209834712
Search for anomalous production of prompt like-sign muon pairs and constraints on physics beyond the standard model with the ATLAS detector
An inclusive search for anomalous production of two prompt, isolated muons with the same electric charge is presented. The search is performed in a data sample corresponding to 1.6 fb(-1) of integr ...
119256577
Measurement of high-Q2 neutral current deep inelastic e−p scattering cross sections with a longitudinally polarised electron beam at HERA
AbstractMeasurements of the neutral current cross sections for deep inelastic scattering in e−p collisions at HERA with a longitudinally polarised electron beam are presented. The single-differential cross-sections dσ/dQ2, dσ/dx and dσ/dy and the double-differential cross sections in Q2 and x are measured in the kinematic region y<0.9 and Q2>185 GeV2 for both positively and negatively polarised electron beams and for each polarisation state separately. The measurements are based on an integrated luminosity of 169.9 pb−1 taken with the ZEUS detector in 2005 and 2006 at a centre-of-mass energy of 318 GeV. The structure functions 
$x\tilde{F_{3}}$ 
and xF3γZ are determined by combining the e−p results presented in this paper with previously measured e+p neutral current data. The asymmetry parameter A− is used to demonstrate the parity violating effects of electroweak interactions at large spacelike photon virtuality. The measurements agree well with the predictions of the Standard Model.