A measurement of Rb using mutually exclusive tags
A measurement of Rb using five mutually exclusive hemisphere tags has been performed by ALEPH using the full LEP1 statistics. Three tags are designed to select the decay of the Z0 to b quarks, while the remaining two select Z0 decays to c and light quarks, and are used to measure the tagging efficiencies. The result, Rb = 0.2159 ± 0.0009(stat) ±0.0011(syst), is in agreement with the electroweak theory prediction of 0.2158 ± 0.0003.

title: Studies of quantum chromodynamics with the ALEPH detector
abstract: Previously published and as yet unpublished QCD results obtained with the ALEPH detector at LEP1 are presented. The unprecedented statistics allows detailed studies of both perturbative and non-perturbative aspects of strong interactions to be carried out using hadronic Z and tau decays. The studies presented include precise determinations of the strong coupling constant, tests of its flavour independence, tests of the SU(3) gauge structure of QCD, study of coherence effects, and measurements of single-particle inclusive distributions and two-particle correlations for many identified baryons and mesons.

title: First measurement of the quark-to-photon fragmentation function
abstract: Earlier measurements at LEP of isolated hard photons in hadronic Z decays, attributed to radiation from primary quark pairs, have been extended in the ALEPH experiment to include hard photon productioninside hadron jets. Events are selected where all particles combine democratically to form hadron jets, one of which contains a photon with a fractional energyz≥0.7. After statistical subtraction of non-prompt photons, the quark-to-photon fragmentation function,D(z), is extracted directly from the measured 2-jet rate. By taking into account the perturbative contributions toD(z) obtained from anO(ααs) QCD calculation, the unknown non-perturbative component ofD(z) is then determined at highz. Provided due account is taken of hadronization effects nearz=1, a good description of the other event topologies is then found.

title: Production of excited beauty states inZ decays
abstract: AbstractA data sample of about 3.0 million hadronicZ decays collected by the ALEPH experiment at LEP in the years 1991 through 1994 is used to make an inclusive selection of B hadron events. In this event sample 4227±140±252B* mesons in the decayB*→Bγ and 1944±108±161B**u,d mesons decaying into a B meson and a charged pion are reconstructed. Here and in the followingB**u,d denotes the eightL=1(bū) and (bd) states and their charge conjugate.For the well establishedB* meson the following quantities are obtained:ΔM=MB*−MB=(45.30±0.35±0.87) MeV/c2 andNB*/(NB+NB*)=(77.1±2.6±7.0)%. The angular distribution of the photons in theB* rest frame is used to measure the relative contribution of longitudinalB* polarization states to beσL/(σL+σT)=(33±6±5)%.In theM(Bπ)−M(B) mass difference resonance structure is observed at (424±4±10) MeV/c2, for which the shape and position is consistent with the expectation forB**u,d states decaying intoB(*)π±. The relative production rate is determined to be
$$\begin{gathered} \frac{{BR(Z \to b \to B_{u,d}^{ * * } )}}{{BR(Z \to b \to B_{u,d} )}} \hfill \\ = [27.9 \pm 1.6(stat) \pm 5.9(syst) {}_{ - 5.6}^{ + 3.9} (model)]\% \hfill \\ \end{gathered} $$
 where the third error reflects the uncertainty due to different production and decay models for the broadB**u,d states.

title: A measurement of the ratio of longitudinal and transverse structure functions in neutrino interactions between 30 and 200 GeV
abstract: A new measurement of the ratio R = σ L / σ T of longitudinal and transverse structure functions in neutrino interactions on iron between 30 and 190 GeV neutrino energy is reported. The result is given as a function of the scale parameter x and the inelasticity ν of the interaction. The average value is R = 0.10 ± 0.07 around ν ≈ 50 GeV and is in accordance with a prediction from the QCD theory.

title: Charged particle pair production associated with a lepton pair in Z decays. indication of an excess in the tau channel
abstract: In a sample of 200 000 Z decays, events with two leptons and an additional pair of charged particles are studied. The 35 events found show a possible excess in the tau channel compared with the expectation from electroweak processes. The features of the events are consistent with radiation of virtual photons.

title: FIRST RF TESTS IN THE HOBICAT SUPERCONDUCTING TEST FACILITY AT BESSY
abstract: In preparation for the construction of the BESSY-FEL User Facility, BESSY recently completed the installation of the HoBiCaT cryogenic test facility for superconducting RF (SRF) TESLA cavity units , including all ancillary devices (helium tank, input coupler, tuner, magnetic shielding). It is designed to house two such units in a configuration similar to that envisaged for the superconducting CW linac of the BESSY FEL. Commissioning of the facility is now complete and the first TTF-III RF coupler and cavity unit has been tested. In particular, the complete production, cleaning and assembly of the cavity unit was carried out by industry. These tests thus serve as a first step at qualifying industrial partners for series production of such systems, which will be essential for the future construction of SRF based light sources.

title: Dark current measurements on a superconducting cavity using a cryogenic current comparator.
abstract: This paper presents nondestructive dark current measurements of tera electron volt energy superconducting linear accelerator cavities. The measurements were carried out in an extremely noisy accelerator environment using a low temperature dc superconducting quantum interference device based cryogenic current comparator. The overall current sensitivity under these rough conditions was measured to be 0.2 nA/Hz(1/2), which enables the detection of dark currents of 5 nA.

title: CATHODE INSERT DESIGN FOR SC RF GUNS
abstract: The cathode inserts in superconducting (SC) RF guns are normal conducting devices attached to a SC RF gun cavity. They enable the photocathode replacement and, at the same time, preserve high quality factor and high fields in the RF guns. However, the insert may also limit the gun performance because of multipacting etc. The experience gathered in early designs at Wuppertal , and, more recently at BNL [2] and HZDR  is taken into account. We consider the design structure of the cathode insert worked out by BINP for 1 cell prototype of SC HZDR RF gun . The detailed electric, mechanic, and thermal calculations of the initial  and the upgraded design are presented in this paper.

title: Status of the HoBiCaT Superconducting Cavity Test Facility at BESSY
abstract: BESSY recently constructed the HOBICAT cryogenic test facility for superconducting TESLA cavity units, including all ancillary devices (helium tank, input coupler, tuner, magnetic shielding). It is designed to house two such units in a configuration similar to that envisaged for the superconducting CW linac of the BESSY FEL. These units are being fabricated, prepared and assembled by industry. HOBICATwill be used to address many of the issues that must be considered prior to finalizing the design of the proposed linac. Rapid turn-around-tests permit the investigation of items such as RF regulation, microphonic detuning and cryogenic parameters/achievable pressure stability. These test will also serve as the first step towards qualifying the industrialproductionofassembled cavity units. The commissioning of HOBICAT began in Spring 2004 and the current status is presented here.

title: CHARACTERIZATION OF A PIEZO-BASED MICROPHONICS COMPENSATION SYSTEM AT HoBiCaT ∗
abstract: In the superconducting driver linac for the BESSY FEL, piezo actuators will be utilized to rapidly counteract the detuning of the cavity resonance caused by nm mechanical oscillations (microphonics). This is of importance to guarantee field stability and lower the power consumption of the RF system for the superconducting cavities. To design a suitablecompensator,mechanicaland electro-mechanical transfer functions, as well as the tuning range of the system under operating conditions have been measured.