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

A high resolution scintillating fiber tracker with SiPM readout for the PEBS experiment

Using thin scintillating fibers with Silicon Photomultiplier (SiPM) readout a mo dular high-resolution charged-particle tracking detector has been designed. The fiber modules consist of 2 x 5 layers of 128 round multiclad scintillating fiber s of 0.250mm diameter. The fibers are read out by four SiPM arrays (8mm x 1mm) e ach on either end of the module.Comment: 6 pages, 5 figures, presented at the ICATPP 1

Supersymmetry without a light Higgs boson but with a light pseudoscalar

We consider the lambda-SUSY model, a version of the NMSSM with large lambda H_1 H_2 S coupling, relaxing the approximation of large singlet mass and negligible mixing of the scalar singlet with the scalar doublets. We show that there are regions of the parameter space in which the lightest pseudoscalar can be relatively light, with unusual consequences on the decay pattern of the CP-even Higgs bosons and thus on the LHC phenomenology.Comment: 11 pages, 3 figures. v3: Conforms to published versio

RECAST: Extending the Impact of Existing Analyses

Searches for new physics by experimental collaborations represent a significant investment in time and resources. Often these searches are sensitive to a broader class of models than they were originally designed to test. We aim to extend the impact of existing searches through a technique we call 'recasting'. After considering several examples, which illustrate the issues and subtleties involved, we present RECAST, a framework designed to facilitate the usage of this technique.Comment: 13 pages, 4 figure

Construction and Test of MDT Chambers for the ATLAS Muon Spectrometer

The Monitored Drift Tube (MDT) chambers for the muon spectrometer of the AT- LAS detector at the Large Hadron Collider (LHC) consist of 3-4 layers of pressurized drift tubes on either side of a space frame carrying an optical monitoring system to correct for deformations. The full-scale prototype of a large MDT chamber has been constructed with methods suitable for large-scale production. X-ray measurements at CERN showed a positioning accuracy of the sense wires in the chamber of better than the required 20 ?microns (rms). The performance of the chamber was studied in a muon beam at CERN. Chamber production for ATLAS now has started

Construction and Test of the Precision Drift Chambers for the ATLAS Muon Spectrometer

The Monitored Drift Tube (MDT) chambers for the muon spectrometer of the ATLAS detector at the Large Hadron Collider (LHC) consist of 3-4 layers of pressurised drift tubes on either side of a space frame carrying an optical deformation monitoring system. The chambers have to provide a track position resolution of 40 microns with a single-tube resolution of at least 80 microns and a sense wire positioning accu- racy of 20 ?microns (rms). The feasibility was demonstrated with the full-scale prototype of one of the largest MDT chambers with 432 drift tubes of 3.8 m length. For the ATLAS muon spectrometer, 88 chambers of this type have to be built. The first chamber has been completed with a wire positioning accuracy of 14 microns (rms)

Determining the Sign of the Z-Penguin Amplitude

We point out that the precision measurements of the pseudo observables R_b^0, A_b, and A_FB^0,b performed at LEP and SLC suggest that in models with minimal-flavor-violation the sign of the Z-penguin amplitude is identical to the one present in the standard model. We determine the allowed range for the non-standard contribution to the Inami-Lim function C and show by analyzing possible scenarios with positive and negative interference of standard model and new physics contributions, that the derived bound holds in each given case. Finally, we derive lower and upper limits for the branching ratios of K^+ -> pi^+ nu nubar, K_L -> pi^0 nu nubar, K_L -> mu^+ mu^-, B -> X_d,s nu nubar, and B_d,s -> mu^+ mu^- within constrained minimal-flavor-violation making use of the wealth of available data collected at the Z-pole.Comment: 20 pages, 5 pdf figures, 5 tables, uses pdflatex; further typos corrected, matches PRD versio

Silicon photomultiplier arrays - a novel photon detector for a high resolution tracker produced at FBK-irst, Italy

A silicon photomultiplier (SiPM) array has been developed at FBK-irst having 32 channels and a dimension of 8.0 x 1.1 mm^2. Each 250 um wide channel is subdivided into 5 x 22 rectangularly arranged pixels. These sensors are developed to read out a modular high resolution scintillating fiber tracker. Key properties like breakdown voltage, gain and photon detection efficiency (PDE) are found to be homogeneous over all 32 channels of an SiPM array. This could make scintillating fiber trackers with SiPM array readout a promising alternative to available tracker technologies, if noise properties and the PDE are improved