15360804
SUSY Searches in All-Hadronic States with Large MET at the LHC
The CMS and ATLAS search strategy for SUSY in inclusive multijet plus high missing transverse energy final states is reviewed. This canonical SUSY signature may be a viable discovery channel for low mass SUSY in the early phase of the LHC. Methods for Standard Model background estimates, MET studies and filters for instrumental background are presented.
125736234
Recent HERMES Results on Inclusive Scattering and Exclusive Reactions
202094757
Diffractive production of Rho0 and omega vector mesons at HERMES
13891794
Vector meson production at HERMES.
Diiractive production of , , ! and J== mesons is observed at the Hermes experiment at DESY. Hermes scatters the 27.5 GeV longitudinally polarised positrons of the HERA storage ring oo an internal gas storage cell target. Polarised and unpolarised gas targets of diierent types are used. The exclusive production from diierent nuclear targets (H, D, 3 He and 14 N) shows coherent and incoherent contributions that depend on the atomic mass A and Q 2. For 3 He the incoherent contribution is smaller than for H and D. The nuclear transparency T has been extracted as a function of Q 2 and and shows no signiicant signal of color transparency eeects. The polari-sation of beam and target at Hermes will allow for the world's rst measurement of double-spin asymmetries in combination with decay angle information. This will allow a nearly complete characterization of the angular momentum structure of the reaction. First results for the longitudinal and linear polarisation of-mesons and for the ratio of the longitudinal versus transverse cross section of-mesons as a function of Q 2 are presented. J== mesons are observed at Hermes in the muonic and the electronic decay channel. As they are produced by photon-gluon fusion processes, the observed spin asymmetry from polarised target data contains information about the gluon spin distribution in the nucleon. As the available statistics is marginal for a determination of G, Hermes currently performs an upgrade of the spectrometer. A ring image Cerenkov detector, a muon detector and a small angle spectrometer will be installed in 1998 and an additional vertex detector in 1999. The upgrade will improve the identiication of charmed and strange mesons, the detection of heavy decaying and slow recoil particles and the detection of the scattered positron in low-Q 2 (photoproduction) events.
119348282
Sum rules in the CFL phase of QCD at finite density
Abstract We study the asymmetry between the vector current and axial-vector current correlators in the colour–flavour locking (CFL) phase of QCD at finite density. Using Weinberg's sum rules, we compute the decay constant f π of the Goldstone modes and find agreement with previous derivations. Using Das's sum rule, we also estimate the contribution of electromagnetic interactions to the mass of the charged modes. Finally, we comment on low temperature corrections to the effective field theory describing the Goldstone bosons.
15529188
Inflation from a tachyon fluid
Motivated by recent works of Sen [hep-th/0203211, hep-th/0203265] and Gibbons [hep-th/0204008], we study the evolution of a flat and homogeneous universe dominated by tachyon matter. In particular, we analyze the necessary conditions for inflation in the early roll of a single tachyon field. Comparison with string theory reveals that the potential is too steep to explain the fluctuations in the CMBR. We suggest a scenario based on the simultaneous decay of many branes and comment on the issue of reheating of the universe after tachyon rolling.
119389066
Anomalies and Fermion Content of Grand Unified Theories in Extra Dimensions
The restrictions imposed by anomaly cancellation on the chiral fermion content of nonsupersymmetric gauge theories based on various groups are studied in spacetime dimension D = 6, 8, and 10. In particular, we show that the only mathematically consistent chiral SU(5) theory in D = 6 contains three nonidentical generations. © 2001 The American Physical Society.
119253725
Is the Lorentz limiting speed equal to the speed of light? Photons vs neutrino tests
We discuss the possibility that the “limiting speed” climit (cl) appearing in Lorentz equations might be different (i.e. slightly larger) than the observed speed of light cn. We show that such a possibility can be tested by state-of-the-art Michelson–Morley experiments, but also by careful measurement of neutrino speeds. It would indeed suffice to show that cn<cν≤cl. Quite interestingly, current limits from both approaches are competitive, in some circumstances. We also comment on competing tests using gamma-ray burst, assuming a dispersive character for the propagation of light.
16746073
Generation of the baryon assymetry of the Universe within the left-right symmetric model
Abstract Fermions scattering off first-order phase transition bubbles, in the framework of SU(2) L ⊗ SU(2) R ⊗ U(1) models, may generate the Baryon Assymetry of the Universe (BAU), either at the LR-symmetry-breaking scale, or at the weak scale. In the latter case, the baryon assymetry of the Universe is related to CP violation in the K 0 − K 0 system.