New Techniques in the Search for Z' Bosons and Other Neutral Resonances

The search for neutral resonances at the energy frontier has a long and illustrious history, resulting in multiple discoveries. The canonical search scans the reconstructed invariant mass distribution of identified fermion pairs. Two recent analyses from the CDF experiment at the Fermilab Tevatron have applied novel methods to resonance searches. One analysis uses simulated templates to fit the inverse mass distribution of muon pairs, a quantity with approximately constant resolution for momenta measured with a tracking detector. The other analysis measures the angular distribution of electron pairs as a function of dielectron mass, gaining sensitivity over a probe of the mass spectrum alone. After reviewing several models that predict new neutral resonances, we discuss these CDF analyses and potential future applications

Black Hole Relics in Large Extra Dimensions

Recent calculations applying statistical mechanics indicate that under the assumption of compactified large extra dimensions a black hole might evolve into a (quasi-)stable state with mass close to the new fundamental scale $M_f$. Black holes and therefore their relics might be produced at the {\sc LHC} in the case of extra-dimensional topologies. In this energy regime, Hawking's evaporation scenario is modified due to energy conservation and quantum effects. We reanalyse the evaporation of small black holes including the quantisation of the emitted radiation due to the finite surface of the black hole. It is found that observable stable black hole relics with masses $\sim 1-3 M_f$ are formed which can be identified by a delayed single jet with a corresponding hard momentum kick to the relic and by ionisation, e.g. in a TPC

Search for TeV γ\gamma -rays from H1426+428 during 2004-07 with the TACTIC telescope

The BL Lac object H1426+428 ($z\equiv 0.129$) is an established source of TeV $\gamma$-rays and detections of these photons from this object also have important implications for estimating the Extragalactic Background Light (EBL) in addition to the understanding of the particle acceleration and $\gamma$-ray production mechanisms in the AGN jets. We have observed this source for about 244h in 2004, 2006 and 2007 with the TACTIC $\gamma$-ray telescope located at Mt. Abu, India. Detailed analysis of these data do not indicate the presence of any statistically significant TeV $\gamma$-ray signal from the source direction. Accordingly, we have placed an upper limit of $\leq1.18\times10^{-12}$ $photons$ $cm^{-2}$ $s^{-1}$ on the integrated $\gamma$-ray flux at 3$\sigma$ significance level.Comment: 11 pages, 5 figures accepted for publication in Journal of Physics G: Nuclear and Particle Physic