Fiber technology applications for a future e+e- linear collider detector

The advantages and possibilities of fiber technology for the detection of particles in 500 GeV e+e- reactions are considered. It is suggested to build a fast trigger which could be used also for intermediate tracking. A fiber preshower in front of the electromagnetic calorimeter would allow to identify electrons and photons with a space precision better than 0.1 mm.Comment: 7 pages, 9 figures. Contributed to Workshop on Scintillating Fiber Detectors (SCIFI97), Notre Dame, IN, 2-6 Nov 199

Deeply-Virtual Compton Scattering on Deuterium and Neon at HERMES

We report the first observation of azimuthal beam-spin asymmetries in hard electroproduction of real photons off nuclei. Attributed to the interference between the Bethe-Heitler process and the deeply-virtual Compton scattering process, the asymmetry gives access to the latter at the amplitude level. This process appears to be the theoretically cleanest way to access generalized parton distributions. The data presented here have been accumulated by the HERMES experiment at DESY, scattering the HERA 27.6 GeV positron beam off deuterium and neon gas targets.Comment: 5 pages, 6 figures. Talk given by F. Ellinghaus at the "15th International Spin Physics Symposium", SPIN 2002, September 9-14, 2002, BNL, Upton, NY, USA. To be published in the proceeding

Measuring the Higgs Branching Fraction into two Photons at Future Linear \ee Colliders

We examine the prospects for measuring the \gaga branching fraction of a Standard Model-like Higgs boson with a mass of 120 GeV at the future TESLA linear \ee collider, assuming an integrated luminosity of 1 ab$^{-1}$ and center-of-mass energies of 350 GeV and 500 GeV. The Higgs boson is produced in association with a fermion pair via the Higgsstrahlung process \ee $\to ZH$, with $Z \to$ \qq or \nn, or the WW fusion reaction $e^+e^- \to \nu_e \bar{\nu_e} H$. A relative uncertainty on BF(\hgg) of~16% can be achieved in unpolarized \ee collisions at $\sqrt{s}$=~500 GeV, while for $\sqrt{s}$=~350 GeV the expected precision is slightly poorer. With appropriate initial state polarizations $\Delta$BF(\hgg)/BF(\hgg) can be improved to 10%. If this measurement is combined with the expected error for the total Higgs width, a precision of 10% on the \gaga Higgs boson partial width appears feasible.Comment: 14 pages, 5 figure

Sensitivity studies for the cubic-kilometre deep-sea neutrino telescope KM3NeT

The observation of high-energy neutrinos from astrophysical sources would substantially improve our knowledge and understanding of the non-thermal processes in these sources, and would in particular pinpoint the accelerators of cosmic rays. The sensitivity of different design options for a future cubic-kilometre scale neutrino telescope in the Mediterranean Sea is investigated for generic point sources and in particular for some of the galactic objects from which TeV gamma emmission has recently been observed by the H.E.S.S. atmospheric Cherenkov telescope. The effect of atmospheric background on the source detection probabilities has been taken into account through full simulation. The estimated event rates are compared to previous results and limits from present neutrino telescopes.Comment: 4 pages, 1 figure, contribution of the 30th International Cosmic Ray conferenc

Testrun results from prototype fiber detectors for high rate particle tracking

A fiber detector concept has been realized allowing to registrate particles within less than 100 nsec with a space point precision of about 0.1 mm at low occupancy. Three full size prototypes have been build by different producers and tested at a 3 GeV electron beam at DESY. After 3 m of light guides 8-10 photoelectrons were registrated by multichannel photomultipliers providing an efficiency of more than 99%. Using all available data a resolution of 0.086 mm was measured.Comment: 18 pages, 17 figure

On ZZ and Z+jetZ + jet Production in Heavy Ion Collisions

Z+jet production in heavy ion collisions at the LHC is proposed as a possible probe of the properties of the dense hadronic matter. It is shown that the accuracy of this measurement with general purpose LHC detectors and under realistic experimental conditions can be high enough. It is argued also that $Z$-boson production and subsequent leptonic decay is a good reference process for this measurement, as well as for the QCD process of high $P_T$ jet pair production.Comment: 8 pages. Send comments to [email protected]