Quaero@H1: An Interface to High-pT HERA Event Data

Distributions from high-pT HERA event data analyzed in a general search for new physics at H1 have been incorporated into Quaero, an algorithm designed to automate tests of specific hypotheses with high energy collider data. The use of Quaero@H1 to search for leptoquarks, R-parity violating supersymmetry, and excited quarks provides examples to develop intuition for the algorithm's performance.Comment: Submitted to Eur. Phys. J.

Strange Particle Production in p+p, p+Pb and Pb+Pb Interactions from NA49

Recent NA49 results on Lambda, Antilambda, Xi- and Antixi+ production in minimum bias p+p and centrality selected p+Pb collisions at 158 GeV/c, and the results on Lambda, Antilambda, K+ and K- production in central Pb+Pb collisions at 40, 80 and 158 A GeV are discussed and compared with other available data. By comparing the energy dependence of Lambda and Antilambda production at mid-rapidity a striking similarity is observed between p+p and A+A data. This is also seen in the energy dependence of the Lambda/pi ratio. K+/pi at mid-rapidity is affected in a similar way, due to the associated production of K+ together with Lambda particles. The observed yields increase faster than the number of wounded nucleons when comparing p+Pb to p+p. As already observed in A+A collisions, the increase is larger for multistrange than for strange baryons and for baryons than for anti-baryons.Comment: 8 pages, 10 figures, To appear in proceedings of Strange Quark in Matter 2001-A Flavourspace Odyssey, Frankfurt am Main, Germany, 24-29. Sept. 200

Azimuth Quadrupole Systematics in Au-Au Collisions

We have measured $p_t$-dependent two-particle number correlations on azimuth and pseudorapidity for eleven centralities of $\sqrt{s_{NN}} = 62$ and 200~GeV Au-Au collisions at STAR. 2D fits to these angular correlations isolate the azimuth quadrupole amplitude, denoted $2 v_2^2 \{ 2D \} ( p_t )$, from localized same-side correlations. Event-plane $v_2 ( p_t )$ measurements within the STAR TPC acceptance can be expressed as a sum of the azimuth quadrupole and the quadrupole component of the same-side peak. $v_2 \{ 2D \} ( p_t )$ can be transformed to reveal quadrupole $p_t$ spectra which are approximately described by a fixed transverse boost and universal L\'evy form nearly independent of centrality. A parametrization of $v_2 \{ 2D \} ( p_t )$ can be factored into centrality and $p_t$-dependent pieces with a simple $p_t$ dependence above 0.75 GeV/c. Results from STAR are compared to published data and model predictions.Comment: Conference proceedings for Hot Quarks 201

Photon-tagged jet measurements in Pb+Pb collisions with the CMS detector

Presented are the results of a detailed study for a complete simulation of the CMS detectors at the LHC in view of the expected modification of jet fragmentation functions in central Pb+Pb collisions at (s_NN)**0.5=5.5 TeV compared to the vacuum (p+p) case. The study is based on photon-jet events, using the correlation between isolated high-transverse energy (E_T>70 GeV) photons and fully reconstructed jets, based on the information provided by the CMS calorimeters and silicon tracker.Comment: 4 pages, 4 figures, ontribution to QM'08 conferenc

Resolved photon and multi-component model for γ∗\gamma^*p and γ∗γ∗\gamma^* \gamma^* scattering at high energies

We generalize our previous model for $\gamma^* p$ scattering to $\gamma \gamma$ scattering. In the latter case the number of components naturally grows. When using the model parameters from our previous $\gamma^* p$ analysis the model cross section for $\gamma \gamma$ scattering is larger than the corresponding LEP2 experimental data by more than a factor of two. However, performing a new simultaneous fit to $\gamma^* p$ and $\gamma \gamma$ total cross section we can find an optimal set of parameters to describe both processes. We propose new measures of factorization breaking for $\gamma^* \gamma^*$ collisions and present results for our new model.Comment: 23 pages, 10 figure

Air Shower Measurements in the Primary Energy Range from PeV to EeV

Recent results of advanced experiments with sophisticated measurements of cosmic rays in the energy range of the so called knee at a few PeV indicate a distinct knee in the energy spectra of light primary cosmic rays and an increasing dominance of heavy ones towards higher energies. This leads to the expectation of knee-like features of the heavy primaries at around 100 PeV. To investigate in detail this energy region several new experiments are or will be devised.Comment: 4 pages; submitted to Proceedings of 2nd Workshop on TeV Astrophysics, Aug 28-31, 2006, Madison, W

Constraining the time variation of the coupling constants from cosmic microwave background: effect of \Lambda_{QCD}

We investigate constraints on the time variation of the fine structure constant between the recombination epoch and the present epoch, \Delta\alpha/\alpha \equiv (\alpha_{rec} - \alpha_{now})/\alpha_{now}, from cosmic microwave background (CMB) taking into account simultaneous variation of other physical constants, namely the electron mass m_{e} and the proton mass m_{p}. In other words, we consider the variation of Yukawa coupling and the QCD scale \Lambda_{QCD} in addition to the electromagnetic coupling. We clarify which parameters can be determined from CMB temperature anisotropy in terms of singular value decomposition. Assuming a relation among variations of coupling constants governed by a single scalar field (the dilaton), the 95% confidence level (C.L.) constraint on \Delta\alpha/\alpha is found to be -8.28 \times 10^{-3} < \Delta\alpha/\alpha < 1.81 \times 10^{-3}, which is tighter than the one obtained by considering only the change of \alpha and m_{e}. We also obtain the constraint on the time variation of the proton-to-electron mass ratio \mu \equiv m_{p}/m_{e} to be -0.52 < \Delta\mu/\mu < 0.17 (95% C.L.) under the same assumption. Finally, we also implement a forecast for constraints from the PLANCK survey.Comment: 25 pages, 4 figures; references adde

Antikaon-nucleus dynamics: from quasibound states to kaon condensation

Coupled-channel Kbar-N dynamics near threshold and its repercussions in few-body Kbar-nuclear systems are briefly reviewed, highlighting studies of a K^-pp quasibound state. In heavier nuclei, the extension of mean-field calculations to multi-Kbar nuclear and hypernuclear quasibound states is discussed. It is concluded that strangeness in finite self-bound systems is realized through hyperons, with no room for kaon condensation.Comment: Proceedings version of plenary talk at Quark Nuclear Physics (QNP09) September 2009, Beijing; matches published versio

Prospects for top-prime quark discovery at the Tevatron

We show that a top-prime quark as heavy as 600 GeV can be discovered at the Tevatron, provided it is resonantly pair-produced via a vector color octet. If the top-prime originates from a vectorlike quark, then the production of a single top-prime in association with a top may also be observable, even through its decay into a Higgs boson and a top. A color octet with mass of about 1 TeV, which decays into a top-prime pair, may account for the CDF excess of semileptonic (Wj)(Wj) events.Comment: 22 pages, 6 ps figures. v2: Note added about the new D0 search for (Wb)(Wb) resonances; section 4.1 expanded; single-top constraint updated in section 2; references adde