Prof Dr Armin Reichold

Abstract:

A new laser-wire (LW) system has been installed at the ATF extraction line at KEK, Tsukuba. The system aims at a micron-scale laser spot size and employs a mode-locked laser system. The purpose-built interaction chamber, light delivery optics, and lens systems are described, and the first results are presented.

Abstract:

We present a study of the dijet invariant mass distribution for the reaction p̄p→twojets+γ+X, at a center of mass energy of 1.8 TeV, using data collected by the CDF experiment. We compare the data to predictions for the production of a photon with two jets, together with the resonant processes p̄p→W/Z+γ+X, in which the W and Z bosons decay hadronically. A fit is made to the dijet invariant mass distribution combining the nonresonant background and resonant processes. We use the result to establish a limit for the inclusive production cross section of W/Z+γ with hadronic decay of the W and Z bosons. © 2006 The American Physical Society.

Abstract:

We are developing a system of interferometers to measure relative motion between two objects (for example, the two final focus quadrupoles of a linear collider) to a few nanometers. Two instruments are under development in the John Adams Institute at the University of Oxford : A distance meter to measure length changes and a straightness monitor to measure perpendicular shifts. We will present the technique, results and resolutions of our distance meter prototype. We also examine the applications of interferometers at the ILC.

Abstract:

A search for the direct production of Higgs bosons in the di-tau decay mode is performed with 86.3±3.5pb-1 of data collected with the Collider Detector at Fermilab during the 1994-1995 data taking period of the Tevatron. We search for events where one tau decays to an electron plus neutrinos and the other tau decays hadronically. We perform a counting experiment and set limits on the cross section for supersymmetric Higgs boson production where tan β is large and mA is small. For a benchmark parameter space point where mA0=100GeV/c2 and tan β=50, we limit the production cross section multiplied by the branching ratio to be less than 77.9 pb at the 95% confidence level compared to the theoretically predicted value of 11.0 pb. This is the first search for Higgs bosons decaying to tau pairs at a hadron collider. © 2005 The American Physical Society.

Abstract:

We present a study of the production of KS0 and Λ0 in inelastic pp̄ collisions at s=1800 and 630 GeV using data collected by the CDF experiment at the Fermilab Tevatron. Analyses of KS0 and Λ0 multiplicity and transverse momentum distributions, as well as of the dependencies of the average number and pT of KS0 and Λ0 on charged particle multiplicity, are reported. Systematic comparisons are performed for the full sample of inelastic collisions, and for the low and high momentum transfer subsamples, at the two energies. The pT distributions extend above 8GeV/c, showing a pT higher than previous measurements. The dependence of the mean KS0(Λ0) pT on the charged particle multiplicity for the three samples shows a behavior analogous to that of charged primary tracks. © 2005 The American Physical Society.