Drift properties of electrons in methane and methane noble gas mixtures
Drift velocities and longitudinal diffusion coefficients are measured with high precision for pure methane, for mixtures of methane with He, Ne, Ar, Kr and Xe as well as for some other molecular gases. From these data, the inelastic cross sections of methane could be determined for the first time. The momentum transfer cross sections of CH 4 and the noble gases were obtained as well, partially with significant deviations from previous measurements. Reliable predictions of the transport parameters in binary and ternary CH 4 noble gas mixtures are now possible.

title: Anisotropic low energy electron collision cross sections for methane derived from transport coefficients
abstract: Based on a comprehensive set of transport parameters of electrons in methane derived from single electron spectra in the range of field 0.01-15 Td the authors determined a set of elastic and inelastic scattering cross sections up to 3 eV. The necessity to include anisotropic elastic scattering in a Boltzmann analysis of methane is demonstrated. In addition the drift velocity in a mixture of methane with helium was used to enhance the reliability of the derived cross sections. The low energy part of the cross sections for elastic scattering is subject to a MERT analysis and is compared with total cross section data from single scattering experiments.

title: HATSouth: A Global Network of Fully Automated Identical Wide-Field Telescopes*
abstract: HATSouth is the world's first network of automated and homogeneous telescopes that is capable of year-round 24 hr monitoring of positions over an entire hemisphere of the sky. The primary scientific goal of the network is to discover and characterize a large number of transiting extrasolar planets, reaching out to long periods and down to small planetary radii. HATSouth achieves this by monitoring extended areas on the sky, deriving high precision light curves for a large number of stars, searching for the signature of planetary transits, and confirming planetary candidates with larger telescopes. HATSouth employs six telescope units spread over three prime locations with large longitude separation in the southern hemisphere (Las Campanas Observatory, Chile; HESS site, Namibia; Siding Spring Observatory, Australia). Each of the HATSouth units holds four 0.18 m diameter f/2.8 focal ratio telescope tubes on a common mount producing an 8.2° × 8.2° field of view on the sky, imaged using four 4 K × 4 K CCD cameras and Sloan r filters, to give a pixel scale of 3.7'' pixel-1. The HATSouth network is capable of continuously monitoring 128 square arc degrees at celestial positions moderately close to the anti-solar direction. We present the technical details of the network, summarize operations, and present detailed weather statistics for the three sites. Robust operations have meant that on average each of the six HATSouth units has conducted observations on ~500 nights over a 2 years time period, yielding a total of more than 1 million science frames at a 4 minute integration time and observing ~10.65 hr day-1 on average. We describe the scheme of our data transfer and reduction from raw pixel images to trend-filtered light curves and transiting planet candidates. Photometric precision reaches ~6 mmag at 4 minute cadence for the brightest non-saturated stars at r ≈ 10.5. We present detailed transit recovery simulations to determine the expected yield of transiting planets from HATSouth. We highlight the advantages of networked operations, namely, a threefold increase in the expected number of detected planets, as compared to all telescopes operating from the same site.

title: Ultrabroadband terahertz source and beamline based on coherent transition radiation
abstract: Coherent transition radiation (CTR) in the THz regime is an important diagnostic tool for analyzing the temporal structure of the ultrashort electron bunches needed in ultraviolet and x-ray free-electron lasers. It is also a powerful source of such radiation, covering an exceptionally broad frequency range from about 200 GHz to 100 THz. At the soft x-ray free-electron laser FLASH we have installed a beam transport channel for transition radiation (TR) with the intention to guide a large fraction of the radiation to a laboratory outside the accelerator tunnel. The radiation is produced on a screen inside the ultrahigh vacuum beam pipe of the linac, coupled out through a diamond window and transported to the laboratory through an evacuated tube equipped with five focusing and four plane mirrors. The design of the beamline has been based on a thorough analysis of the generation of TR on metallic screens of limited size. The optical propagation of the radiation has been computed taking into account the effects of near-field (Fresnel) diffraction. The theoretical description of the TR source is presented in the first part of the paper, while the design principles and the technical layout of the beamline are described in the second part. First experimental results demonstrate that the CTR beamline covers the specified frequency range and preserves the narrow time structure of CTR pulses emitted by short electron bunches.

title: Luminosity determination at HERA-B
abstract: A detailed description of an original method used to measure the luminosity accumulated by the HERA-B experiment for a data sample taken during the 2002–2003 HERA running period is reported. We show that, with this method, a total luminosity measurement can be achieved with a typical precision, including overall systematic uncertainties, at a level of 5% or better. We also report evidence for the detection of δ -rays generated in the target and comment on the possible use of such delta rays to measure luminosity.

title: BUNCH COMPRESSION MONITOR
abstract: The longitudinal charge distribution in the electron bunches has a strong impact on the lasing process in a Free-Electron Laser based on the principle of Self Amplified Spontaneous Emission of radiation. For the ultraviolet and soft X ray FEL FLASH at DESY, structures in the range of ten to hundred micrometers play a crucial role. The investigation of the longitudinal charge distribution in the electron bunches on a bunch-by-bunch basis is an important issue for optimizing the bunch compression and improving the performance of the machine. This paper introduces a new tool for longitudinal diagnostics based on THz spectroscopy of coherent radiation. A novel spectrometer has been designed which permits to analyze the radiation of single electron bunches in a broad spectral range and with high resolution. Preliminary measurements with this spectrometer are presented. A strong variation of the CTR intensity in the 40 μm regime is observed when the off-crest phase in the accelerating cavities preceding the first magnetic bunch compressor is changed in small steps. This variation in the CTR intensity is found to be correlated with a similar variation in the pulse energy of the FEL light. Hence the THz spectrometer appears to be a very sensitive device for controlling the parameters of the bunch compression scheme.

title: A study of quasi-elastic muon neutrino and antineutrino scattering in the NOMAD experiment
abstract: AbstractWe have studied the muon neutrino and antineutrino quasi-elastic (QEL) scattering reactions (νμn→μ−p and 
$\bar{\nu }_{\mu}p\to\mu^{+}n$
) using a set of experimental data collected by the NOMAD Collaboration. We have performed measurements of the cross-section of these processes on a nuclear target (mainly carbon) normalizing it to the total νμ (
$\bar{\nu}_{\mu}$
) charged-current cross section. The results for the flux-averaged QEL cross sections in the (anti)neutrino energy interval 3–100 GeV are 
$\langle \sigma_{\mathrm{qel}}\rangle_{\nu_{\mu}}=(0.92\pm0.02(\mathrm{stat})\pm0.06(\mathrm{syst}))\times10^{-38}~\mathrm{cm}^{2}$ 
and 
$\langle\sigma_{\mathrm{qel}}\rangle_{\bar{\nu}_{\mu}}=(0.81\pm0.05(\mathrm{stat})\pm0.09(\mathrm{syst}))\times10^{-38}~\mathrm{cm}^{2}$ 
for neutrino and antineutrino, respectively. The axial mass parameter MA was extracted from the measured quasi-elastic neutrino cross section. The corresponding result is MA=1.05±0.02(stat)±0.06(syst) GeV. It is consistent with the axial mass values recalculated from the antineutrino cross section and extracted from the pure Q2 shape analysis of the high purity sample of νμ quasi-elastic 2-track events, but has smaller systematic error and should be quoted as the main result of this work. Our measured MA is found to be in good agreement with the world average value obtained in previous deuterium filled bubble chamber experiments. The NOMAD measurement of MA is lower than those recently published by K2K and MiniBooNE Collaborations. However, within the large errors quoted by these experiments on MA, these results are compatible with the more precise NOMAD value.

title: Time resolution limits of the MWPCs for the LHCb muon system
abstract: Detailed simulations of the timing properties of the Multi-Wire-Proportional-Chambers of the LHCb muon system are compared with actual measurements. The simulated time resolution is in good agreement with the measurement which allows to study the resolution limiting parameters like diffusion, charge deposit fluctuations, cluster position fluctuations, electronics noise, track position and wire spacing to show how they affect the performance of the system. Methods to improve the time resolution of the muon chambers are discussed.

title: Measurement of the semileptonic $CP$ asymmetry in $B^0-\overline{B}{}^0$ mixing
abstract: The semileptonic $CP$ asymmetry in $B^0-\overline{B}{}^0$ mixing, $a_{\rm sl}^d$, is measured in proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb$^{-1}$, recorded by the LHCb experiment. Semileptonic $B^0$ decays are reconstructed in the inclusive final states $D^-\mu^+$ and $D^{*-}\mu^+$, where the $D^-$ meson decays into the $K^+\pi^-\pi^-$ final state, and the $D^{*-}$ meson into the $\overline{D}{}^0(\rightarrow K^+\pi^-)\pi^-$ final state. The asymmetry between the numbers of $D^{(*)-}\mu^+$ and $D^{(*)+}\mu^-$ decays is measured as a function of the decay time of the $B^0$ mesons. The $CP$ asymmetry is measured to be $a_{\rm sl}^d = (-0.02 \pm 0.19 \pm 0.30)\%$, where the first uncertainty is statistical and the second systematic. This is the most precise measurement of $a_{\rm sl}^d$ to date and is consistent with the prediction from the Standard Model.

title: An indication of evolution of type ia supernovae from their risetimes
abstract: We have compared the risetime for samples of nearby and high-redshift type Ia supernovae (SNe Ia). 
The fiducial risetime of the nearby SNe Ia is 2.5+/-0.4 days longer than the proemial risetime determined by Goldhaber (1998a,b) for high-redshift SNe 
Ia from the Supernova Cosmology Project. 
The statistical likelihood that the two samples have different fiducial risetimes is high (5.8 sigma) and indicates possible evolution between the samples of SNe Ia. We consider the likely effects of several sources of systematic error, but none of these resolves the difference in the risetimes. 
Currently, we cannot directly determine the impact of the apparent evolution on previous determinations of cosmological parameters.

title: A New Population of High-Redshift Short-Duration Gamma-Ray Bursts
abstract: The redshift distribution of the short-duration gamma-ray bursts (GRBs) is a crucial, but currently fragmentary, cluetothenatureoftheirprogenitors.HerewepresentopticalobservationsofnineshortGRBsobtainedwithGemini, Magellan, and the Hubble Space Telescope. We detect the afterglows and host galaxies of two short bursts, and host galaxiesfortwoadditionalburstswithknownopticalafterglowpositions,andfivewithX-raypositions(P6 00 radius).In eightoftheninecaseswefindthatthemostprobablehostgalaxiesarefaint,R � 23 26:5mag,andarethereforestarkly different from the first few short GRB hosts with R � 17 22 mag and z P0:5. Indeed, we measure spectroscopic redshifts ofz � 0:4 1:1for the four brightest hosts. A comparison to largefield galaxy samples, as well as the hosts of longGRBsandpreviousshortGRBs,indicatesthatthefainterhostslikelyresideatz k1. Ourmostconservativelimit is that at least half of the five hosts without a known redshift reside at z > 0:7 (97% confidence level), suggesting that about 1 to 2 of all short GRBs originate at higher redshifts than previously determined. This has two important implications: (1) we constrain the acceptable age distributions to a wide lognormal (� k1) with � � � 4 8G yr, or to a powerlaw,P(� ) / � n ,with � 1Pn P0;and(2)theinferredisotropicenergies,E�; iso � 1050 10 52 ergs,aresignificantly larger than � 10 48 ‐10 49 ergs for the low-redshift, short GRBs, indicating a large spread in energy release or jet opening angles. Finally, we reiterate the importance of short GRBs as potential gravitational-wave sources and find a conservative detection rate with the advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) of � 2‐6 yr � 1 .