arXiv subjects

H. -C. Schultz-Coulon

Publications and source records attributed to H. -C. Schultz-Coulon.

5 recordsLinked to original sources

arXiv2021

Technical design of the phase I Mu3e experiment

The Mu3e experiment aims to find or exclude the lepton flavour violating decay $μ\rightarrow eee$ at branching fractions above $10^{-16}$. A first phase of the experiment using an existing beamline at the Paul Scherrer Institute (PSI) is designed to reach a single event sensitivity of $2\cdot 10^{-15}$. We present an overview of all aspects of the technical design and expected performance of the phase~I Mu3e detector. The high rate of up to $10^{8}$ muon decays per second and the low momenta of the decay electrons and positrons pose a unique set of challenges, which we tackle using an ultra thin tracking detector based on high-voltage monolithic active pixel sensors combined with scintillating fibres and tiles for precise timing measurements.

physics.ins-det↗

arXiv2013

Research Proposal for an Experiment to Search for the Decay μ -> eee

We propose an experiment (Mu3e) to search for the lepton flavour violating decay mu+ -> e+e-e+. We aim for an ultimate sensitivity of one in 10^16 mu-decays, four orders of magnitude better than previous searches. This sensitivity is made possible by exploiting modern silicon pixel detectors providing high spatial resolution and hodoscopes using scintillating fibres and tiles providing precise timing information at high particle rates.

physics.ins-det↗

arXiv2012

Towards testing a two-Higgs-doublet model with maximal CP symmetry at the LHC: construction of a Monte Carlo event generator

A Monte Carlo event generator is constructed for a two-Higgs-doublet model with maximal CP symmetry, the MCPM. The model contains five physical Higgs bosons; the $ρ'$, behaving similarly to the standard-model Higgs boson, two extra neutral bosons $h'$ and $h"$, and a charged pair $H^\pm$. The special feature of the MCPM is that, concerning the Yukawa couplings, the bosons $h'$, $h"$ and $H^\pm$ couple directly only to the second generation fermions but with strengths given by the third-generation-fermion masses. Our event generator allows the simulation of the Drell-Yan-type production processes of $h'$, $h"$ and $H^\pm$ in proton-proton collisions at LHC energies. Also the subsequent leptonic decays of these bosons into the $μ^+ μ^-$, $μ^+ ν_μ$ and $μ^- \bar ν_μ$ channels are studied as well as the dominant background processes. We estimate the integrated luminosities needed in $p p$ collisions at center-of-mass energies of 8 TeV and 14 TeV for significant observations of the Higgs bosons $h'$, $h"$ and $H^\pm$ in these muonic channels.

hep-ph↗

arXiv2003

On the Investigation of the Proton Structure Using QED Compton Events in ep Scattering

QED Compton scattering at HERA is discussed in terms of the information it may reveal on the proton structure at low momentum transfers Q2. Detailed Monte Carlo studies are performed which show that the analysis of inelastic QED Compton events allows the extension of present HERA structure function measurements to a kinematic regime, which up to now was only accessed in fixed target data. For these studies an improved version of the COMPTON event generator is used, where special emphasis has been put on modelling the hadronic final state at low invariant masses. As the low Q2 regime is sometimes also discussed in the context of the collinear approximation and the possibility of measuring the photonic content of the proton, the Monte Carlo studies are also used to check the validity of this approach. It is found that the proposed concept of a photon density of the proton does not provide sufficient accuracy for the description of inelastic QED Compton scattering.

hep-ph↗

arXiv2001

A Fast High Resolution Track Trigger for the H1 Experiment

After 2001 the upgraded ep collider HERA will provide an about five times higher luminosity for the two experiments H1 and ZEUS. In order to cope with the expected higher event rates the H1 collaboration is building a track based trigger system, the Fast Track Trigger (FTT). It will be integrated in the first three levels (L1-L3) of the H1 trigger scheme to provide higher selectivity for events with charged particles. The FTT will allow to reconstruct 3-dimensional tracks in the central drift chamber down to 100 MeV/c within the L2 latency of ~ 23 mus. To reach the necessary momentum resolution of ~ 5% (at 1 GeV/c) sophisticated reconstruction algorithms have to be implemented using high density Field Programmable Gate Arrays (FPGA) and their embedded Content Addressable Memories (CAM). The final track parameter optimization will be done using non-iterative fits implemented in DSPs. While at the first trigger level rough track information will be provided, at L2 tracks with high resolution are available to form trigger decisions on topological and other track based criteria like multiplicities and momenta. At the third trigger level a farm of commercial processor boards will be used to compute physics quantities such as invariant masses.

hep-ex↗