18347743
Building CMS pixel barrel detector modules
For the barrel part of the CMS pixel tracker about 800 silicon pixel detector modules are required. The modules are bump bonded, assembled and tested at the Paul Scherrer Institute. This article describes the experience acquired during the assembly of the first ∼200 modules.
15533358
CMS barrel pixel detector overview
Abstract The pixel detector is the innermost tracking device of the CMS experiment at the LHC. It is built from two independent subdevices, the pixel barrel and the end disks. The barrel consists of three concentric layers around the beam pipe with mean radii of 4.4, 7.3 and 10.2 cm. There are two end disks on each side of the interaction point at ± 34.5 and ± 46.5 cm . This article gives an overview of the pixel barrel detector, its mechanical support structure, electronics components, services and its expected performance.
17874828
High-frequency VLBI observations of Sgr A* during a multi-frequency campaign in May 2007
In May 2007 the compact radio source Sgr A* was observed in a global multi-frequency monitoring campaign, from radio to X-ray bands. Here we present and discuss first and preliminary results from polarization sensitive VLBA observations, which took place during May 14-25, 2007. Here, Sgr A* was observed in dual polarization on 10 consecutive days at 22, 43, and 86 GHz. We describe the VLBI experiments, our data analysis, monitoring program and show preliminary images obtained at the various frequencies. We discuss the data with special regard also to the short term variability.
119028863
${}^{3}\mathrm{He}$ and $pd$ Scattering to Next-to-Leading Order in Pionless Effective Field Theory
We study the three-body systems of ${}^{3}\mathrm{He}$ and $pd$ scattering and demonstrate, both analytically and numerically, that a new $pd$ three-body force is needed at next-to-leading order in pionless effective field theory. We also show that at leading order these observables require no new three-body force beyond what is necessary to describe $nd$ scattering. We include electromagnetic effects by iterating only diagrams that involve a single photon exchange in the three-body sector.
119249399
Precision calculation of the quartet-channel p-d scattering length
We present a fully perturbative calculation of the quartet-channel proton--deuteron scattering length up to next-to-next-to-leading order in pionless effective field theory. We use a framework that consistently extracts the Coulomb-modified effective range function for a screened Coulomb potential in momentum space and allows for a clear linear extrapolation back to the physical limit without screening. Our result of (10.9 +/- 0.4) fm agrees with older experimental determinations of this quantity but deviates from potential-model calculations and a more recent result from Black et al., which find larger values around 14 fm. As a possible resolution to this discrepancy, we discuss the scheme dependence of Coulomb subtractions in a three-body system.