118869536
Physics of Relativistic Perfect Fluids
A criterion is presented and discussed to detect when a divergence-free perfect fluid energy tensor in the space-time describes an evolution in local thermal equilibrium. 
This criterion is applied to the class II Szafron-Szekeres perfect fluid space-times solutions, giving a very simple characterization of those that describe such thermal evolutions. For all of them, the significant thermodynamic variables are explicitly obtained. 
Also, the specific condition is given under which the divergence-free perfect fluid energy tensors may be interpreted as an ideal gas.
14972296
Vacuum type I spacetimes and aligned Papapetrou fields: symmetries
We analyse type I vacuum solutions admitting an isometry whose Killing 2-form is aligned with a principal bivector of the Weyl tensor, and we show that these solutions belong to a family of type I metrics which admit a group G3 of isometries. We give a classification of this family and study the Bianchi type for each class. The classes compatible with an aligned Killing 2-form are also determined. The Szekeres–Brans theorem is extended to non-vacuum spacetimes with vanishing Cotton 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.
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.
6470358
Aligned Electric and Magnetic Weyl Fields
The results on the non-existence of purely magnetic solutions are extended to the wider class of spacetimes which have homothetic electric and magnetic Weyl fields. This class is a particularization of the spacetimes admitting a direction for which the relative electric and magnetic Weyl fields are aligned. We give an invariant characterization of these metrics and study the properties of their Debever null vectors. The directions ‘observing’ aligned electric and magnetic Weyl fields are obtained for every Petrov-Bel type.
12797209
Summary of the Electroweak and Beyond the Standard Model Working Group
For more than a century, high energy collisions of particles have been the golden method of investigating the ultimate structure of matter. Along with precision studies of heavy meson decays, primarily at lower energy colliders, these experiments have led to consolidation of the Standard Model (SM) as the theory of particle physics at energy scales up to O(10) GeV. Recent results from high energy colliders HERA and the TeVatron, complemented by the extraordinary precision measurements from the b-factories, display no significant deviations from SM predictions.
17225927
Measurement of azimuthal asymmetries in neutral current deep inelastic scattering at HERA
The distribution of the azimuthal angle of charged and neutral hadrons relative to the lepton plane has been studied for neutral current deep inelastic ep scattering using an integrated luminosity of 45 pb-1 taken with the ZEUS detector. The kinematic range is 100<Q2<8000 GeV2, 0.2<y<0.8 and 0.01<x<0.1 where Q2 is the virtuality of the exchanged boson, y is the inelasticity and x is the Bjorken variable. The measurements were made in the hadronic centre-of-mass system. The analysis exploits the energy-flow method, which allows the measurement to be made over a larger range of pseudorapidity compared to previous results. The dependence of the moments of the azimuthal distributions on the pseudorapidity and minimum transverse energy of the final-state hadrons are presented. Although the predictions from next-to-leading-order QCD describe the data better than do the Monte Carlo models incorporating leading-logarithm parton showers, they still fail to describe the magnitude of the asymmetries. This suggests that higher-order calculations may be necessary to describe these data. 
29379793
Scaled momentum spectra in deep inelastic scattering at HERA
Charged particle production has been studied in neutral current deep inelastic ep scattering with the ZEUS detector at HERA using an integrated luminosity of 0.44 fb−1. Distributions of scaled momenta in the Breit frame are presented for particles in the current fragmentation region. The evolution of these spectra with the photon virtuality, Q2, is described in the kinematic region 10 < Q2 < 41000Ge V2. Next-to-leading-order and modified leading-log-approximation QCD calculations as well as predictions from Monte Carlo models are compared to the data. The results are also compared to e+e− annihilation data. The dependences of the pseudorapidity distribution of the particles on Q2 and on the energy in the γp system, W, are presented and interpreted in the context of the hypothesis of limiting fragmentation.
209834301
Search for supersymmetry in events with photons, bottom quarks, and missing transverse momentum in proton–proton collisions at a centre-of-mass energy of 7 TeV with the ATLAS detector
A search has been performed for the experimental signature of an isolated photon with high transverse momentum, at least one jet identified as originating from a bottom quark, and high missing transverse momentum. Such a final state may originate from supersymmetric models with gauge-mediated supersymmetry breaking in events in which one of a pair of higgsino-like neutralinos decays into a photon and a gravitino while the other decays into a Higgs boson and a gravitino. The search is performed using the full dataset of 7 TeV proton–proton collisions recorded with the ATLAS detector at the LHC in 2011, corresponding to an integrated luminosity of 4.7 fb−1. A total of 7 candidate events are observed while 7.5±2.2 events are expected from the Standard Model background. The results of the search are interpreted in the context of general gauge mediation to exclude certain regions of a benchmark plane for higgsino-like neutralino production.
11433826
Isolated Leptons with missing transverse momentum and Search for single top production
Recent results of searches for production of isolated leptons in events w ith large missing transverse momentum in e±p collisions at HERA are reviewed. The H1 collaboration observes an exce ss of these events over the, W-production dominated, Standard Model (SM) predictions in e+ p collisions, this excess is not confirmed by ZEUS. In e−p collisions the rate of these events observed by the H1 collaboration is consistent with th e Standard Model predictions. A potential new-physics source of isolated leptons in events with large missing transve rse momentum at HERA is single top production via flavour changing neutral currents (FCNC). The most rece nt results of searches for this process from the H1 collaboration are presented including limits on the FCNC couplings. The HERA limits remain the strongest on photonic FCNC. International Europhysics Conference on High Energy Physics 2005 Lisboa, Portugal Table 1: The numbers of observed events in different PX T ranges in the H1 isolated high pT lepton search compared to the SM expectations. The fraction of singleW production included in the expectation is indicated in pare nth ses. The statistical and systematic uncertainties, added in quadra ture, are also indicated. Electron Muon Combined H1 Preliminary obs./exp. ( W ) obs./exp. ( W ) obs./exp. ( W ) 1994-2004 Full Sample 19/14.6±2.0(70%) 9/3.9±0.6(84%) 28/18.5±2.7(73%) 158 pb−1 e+ p pT > 25 GeV 9/2.3±0.4(80%) 6/2.3±0.4(84%) 15/4.6±0.8(82%) 1998-2005 Full Sample 6/5.8±0.9(62%) 0/1.5±0.5(76%) 6/7.3±1.4(65%) 53 pb−1 e−p pT > 25 GeV 2/0.9±0.2(71%) 0/0.9±0.2(73%) 2/1.8±0.3(72%) 1994-2005 Full Sample 25/20.4±2.9(68%) 9/5.4±1.1(82%) 34/25.7±4.0(71%) 211 pb−1 e±p pT > 25 GeV 11/3.2±0.6(77%) 6/3.2±0.5(81%) 17/6.4±1.1(79%) Table 2: The numbers of observed events in the ZEUS isolated l epton search, compared to the SM expectations. The fraction of singleW production included in the expectation is indicated in pare nth ses. The statistical and systematic uncertainties added in quadrature are also indicated. Isolatede candidates 12< PX T < 25 GeV P X T > 25 GeV ZEUS (prel.) 99-00 (66 pb −1) 1/1.04±0.11(57%) 1/0.92±0.09(79%) ZEUS (prel.) 03-04 (40 pb −1) 0/0.46±0.10(64%) 0/0.58+0.08 −0.09(76%) 1 Isolated leptons in events with missing transverse momentum The observation of anomalous events with an isolated high en ergy lepton and missing transverse momentum in ep collisions at HERA was reported by the H1 collaboration at the end o f the 1994-2000 running period [1]. Production of single W bosons with subsequent leptonic decay is the only process wi th a measurable cross section at HERA which leads to this type of events. The dominant leading order Feynman diag ram for W production is shown in Fig.1(a); the total cross section is about 1 pb, evaluated including O(ααs) QCD corrections [2]. New results in searches for isolated electrons and muons fro m H1 for the 1994-2005 running period are summarised in Table 1 [3]. An excess of observed data over the SM expectat ions can be seen in the H1 results, this is illustrated in Fig.1(b). This excess is actually observed only in the e+ p data (see Table 1), it is not confirmed in a similar search by th e ZEUS collaboration [4], which is summarised in Table 2. The e xcess over the SM prediction at high values of hadronic PT is suggestive of a heavy particle decay process. More specia lis d searches have been applied to look for high pT leptons arising from the leptonic decay channel of single-top produ ction, as discussed in section 2. A slight excess in theτ channel was reported by ZEUS for 130 pb −1 of data from the 1994-2000 running period [5]. The results of the latest H1 search for isolated τ leptons using 108 pb −1 of data from the 1996-2000 running period [6] are given in Table 3. No excess over the SM is observed.