Study on the effect of contamination on the performance of X-ray telescopes

Modifications were made to the X-ray reflectometer located at the Space Sciences Laboratory, Marshall Space Flight Center. One was an automatic drive for the Large Micrometer Head. This system, interfaced with the Hewlett Packard Computer System, is used to record data and provides the X-ray reflectometer with an automated data-taking capability. Using this system, a complete scatter curve can be obtained automatically. Previously, it was necessary to manually reset the system after recording for each data point in the scatter curve. The second modification provided an externally controlled electrical drive to move the microfocus X-ray source along its axis. With this modification, one can translate the X-ray source while it is operating to locate the position providing maximum count rate

The calibration of a Ge(Li) gamma-ray spectrometer for energy and relative intensity measurements

Two aspects of Ge(Li) gamma-ray spectrometry are discussed. The non-linearity of an amplifier-analyzer system was measured using a precision pulser and was checked with gamma-ray standards. The overall accuracy was 2 parts in 104. The relative detection efficiency of gamma-ray full-energy peaks was determined using sources with well measured relative gamma-ray emission rates. Two Ge(Li) detectors with active volumes of 3 cm2 x 0.5 cm and 4 cm2 x 0.5 cm were calibrated in the energy range 80--3200 keV. An overall accuracy of 5% in the energy region from 500-3200 keV and an accuracy of 10% over the entire range was obtained. The relative areas of the single escape peak and double escape peak to the full energy peak as a function of energy are included. The relative intensities of the 569.6, 1063.6 and 1771 keV gamma-rays following the decay of 207Bi were measured.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33388/1/0000787.pd

Versuchsbeschrieb und Qualität des frischen Wiesenfutters : Serie Systemvergleich Hohenrain II

Im Systemvergleich Hohenrain II wurden drei Fütterungssysteme auf Basis von frischem Wiesenfutter miteinander verglichen. Dazu wurden von 2014-2016 die zwei Systeme Teilweide mit Eingrasen und reduzierter (EGKF) beziehungsweise erhöhter Kraftfuttergabe (EGKFplus) mit der Vollweide (VW) als Referenzsystem verglichen. Auf dem Gutsbetrieb des BBZN Hohenrain in Luzern wurden drei Herden in je einem Fütterungssystem gehalten. Allen Herden stand dieselbe Futterfläche zur Verfügung. Auch 36 Pilotbetriebe aus dem Schweizer Mittelland beteiligten sich am Projekt und unterstützten über die Teilnahme an Arbeitskreisen die Praxisverknüpfung und den Wissenstransfer. Die höchsten Energiegehalte im Eingrasfutter wurden im Frühjahr erreicht. Diese sind mit den bekannten Tabellenwerten vergleichbar. Gegenüber den Kurzrasenweiden lagen die Gehalte bedeutend tiefer und waren insbesondere über die Sommermonate starken Schwankungen unterworfen. Dies wird auf das Nutzungsstadium und die sommerlichen Witterungseinflüsse zurückgeführt, welche die Verdaulichkeit des Wiesenfutters wesentlich beeinflussen. Analog zur Weide sollten deshalb Entscheidungshilfen entwickelt werden, welche die Praxis bei der Nutzung der Eingrasbestände im optimalen Stadium unterstützen.In Svizzera molte aziende produttrici di latte fanno uso di sostanziali percentuali di foraggio verde nella razione alimentare. Obiettivo di questo progetto è stata la comparazione tra tre sistemi che si basano sull’alimentazione del bestiame con man-gime verde fresco. A tale scopo, tra il 2014 e il 2016, i due sistemi a pascolo parziale con afforaggiamento di erba fresca e apporto di concentrati ridotto (EGKF) o maggiorato (EGKFplus) sono stati messi a confronto, assumendo il pascolo integrale (VW) come sistema di riferimento. Il presente articolo informa sul dispositivo dell’esperimento e sui primi risultati riguardanti il contenuto di energia del foraggio verde fresco. Nell’a-zienda agricola del centro di formazione professionale BBZN di Hohenrain (LU) il bestiame da latte (70 capi) è stato suddiviso in tre mandrie e inserito nei rispettivi sistemi di foraggiamento. Ad ogni mandria è stata messa a disposizione la stessa superficie di terreno per il pascolo o le colture foraggere (12 ha), mentre la media del numero di mucche e la quantità di mangime concen-trato impiegato erano differenziate in base ai diversi sistemi. Anche 36 aziende agricole dell’altopiano svizzero hanno preso parte al progetto, sostenendo la messa in pratica e il trasferimento del sapere tramite la parteci-pazione a gruppi di lavoro. I tenori più alti di energia netta di lattazione (NEL) nel forag-gio verde (MJ/kg SS) sono stati raggiunti in primavera, ed erano paragonabili ai valori delle tabelle di riferimento. I tenori sono risultati essere significativamente inferiori rispetto a quelli del pascolo ad erba corta e sono stati soggetti a forti oscillazioni soprat-tutto nei mesi estivi. Ciò è da ricondurre all’irregolare stadio di maturazione dell’erba al momento della raccolta e alle condizioni metereologiche, che influenzano di molto la digeribilità del foraggio verde. Supporti decisionali alla pratica dell’afforaggiamento di erba fresca potrebbero contribuire a migliorare la situazione.Partial grazing with indoor feeding of fresh grass is an important feeding system for Swiss dairy farms. From 2014 to 2016, three production systems – ‘partial grazing with indoor feeding of fresh grass with reduced (EGKF, 418 kg) and increased concentrate supplementation (EGKFplus; 1161 kg) was compared with full-time grazing (FG) with reduced concentrate supplementation on 36 pilot farms in Switzerland. This article describes the set-up and initial results regarding the energy content of the fresh grass. The seventy-head dairy herd on the BBZN Hohenrain school farm in Lucerne was divided into three sub-herds, each of which was kept in one of the three feeding systems. While all three herds had the same amount of land at their disposal as pasture or foddergrowing land (12 ha), the average number of cows and the quantity of concentrate used differed according to the system. Thirty-six pilot farms in the Swiss Plateau were also involved in the project and gave support by participating in study groups focussing on linking practice and transferring knowledge. The highest NEL contents in grass fodder (MJ/kg DM) were measured in spring. These were comparable with reference values. However, compared to continuous grazing, the contents were significantly lower and, particularly during summer, were subject to strong fluctuations. This is a result of the irregular utilisation stage and the influence of summer weather conditions, both of which significantly impact the digestibility of grass fodder. Decision-making aids to support practitioners with forage harvesting could lead to improvements here

Fermilab E791

Fermilab E791, a very high statistics charm particle experiment, recently completed its data taking at Fermilab's Tagged Photon Laboratory. Over 20 billion events were recorded through a loose transverse energy trigger and written to 8mm tape in the the 1991-92 fixed target run at Fermilab. This unprecedented data sample containing charm is being analysed on many-thousand MIP RISC computing farms set up at sites in the collaboration. A glimpse of the data taking and analysis effort is presented. We also show some preliminary results for common charm decay modes. Our present analysis indicates a very rich yield of over 200K reconstructed charm decays.Comment: 4 pages, 1 figure, LaTe

A Study of Time-Dependent CP-Violating Asymmetries and Flavor Oscillations in Neutral B Decays at the Upsilon(4S)

We present a measurement of time-dependent CP-violating asymmetries in neutral B meson decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at the Stanford Linear Accelerator Center. The data sample consists of 29.7 ${\rm fb}^{-1}$ recorded at the $\Upsilon(4S)$ resonance and 3.9 ${\rm fb}^{-1}$ off-resonance. One of the neutral B mesons, which are produced in pairs at the $\Upsilon(4S)$, is fully reconstructed in the CP decay modes $J/\psi K^0_S$, $\psi(2S) K^0_S$, $\chi_{c1} K^0_S$, $J/\psi K^{*0}$ ($K^{*0}\to K^0_S\pi^0$) and $J/\psi K^0_L$, or in flavor-eigenstate modes involving $D^{(*)}\pi/\rho/a_1$ and $J/\psi K^{*0}$ ($K^{*0}\to K^+\pi^-$). The flavor of the other neutral B meson is tagged at the time of its decay, mainly with the charge of identified leptons and kaons. The proper time elapsed between the decays is determined by measuring the distance between the decay vertices. A maximum-likelihood fit to this flavor eigenstate sample finds $\Delta m_d = 0.516\pm 0.016 {\rm (stat)} \pm 0.010 {\rm (syst)} {\rm ps}^{-1}$. The value of the asymmetry amplitude $\sin2\beta$ is determined from a simultaneous maximum-likelihood fit to the time-difference distribution of the flavor-eigenstate sample and about 642 tagged $B^0$ decays in the CP-eigenstate modes. We find $\sin2\beta=0.59\pm 0.14 {\rm (stat)} \pm 0.05 {\rm (syst)}$, demonstrating that CP violation exists in the neutral B meson system. (abridged)Comment: 58 pages, 35 figures, submitted to Physical Review

Measurement of the Branching Fraction for B- --> D0 K*-

We present a measurement of the branching fraction for the decay B- --> D0 K*- using a sample of approximately 86 million BBbar pairs collected by the BaBar detector from e+e- collisions near the Y(4S) resonance. The D0 is detected through its decays to K- pi+, K- pi+ pi0 and K- pi+ pi- pi+, and the K*- through its decay to K0S pi-. We measure the branching fraction to be B.F.(B- --> D0 K*-)= (6.3 +/- 0.7(stat.) +/- 0.5(syst.)) x 10^{-4}.Comment: 7 pages, 1 postscript figure, submitted to Phys. Rev. D (Rapid Communications

Evidence for the Rare Decay B -> K*ll and Measurement of the B -> Kll Branching Fraction

We present evidence for the flavor-changing neutral current decay $B\to K^*\ell^+\ell^-$ and a measurement of the branching fraction for the related process $B\to K\ell^+\ell^-$, where $\ell^+\ell^-$ is either an $e^+e^-$ or $\mu^+\mu^-$ pair. These decays are highly suppressed in the Standard Model, and they are sensitive to contributions from new particles in the intermediate state. The data sample comprises $123\times 10^6$ $\Upsilon(4S)\to B\bar{B}$ decays collected with the Babar detector at the PEP-II $e^+e^-$ storage ring. Averaging over $K^{(*)}$ isospin and lepton flavor, we obtain the branching fractions ${\mathcal B}(B\to K\ell^+\ell^-)=(0.65^{+0.14}_{-0.13}\pm 0.04)\times 10^{-6}$ and ${\mathcal B}(B\to K^*\ell^+\ell^-)=(0.88^{+0.33}_{-0.29}\pm 0.10)\times 10^{-6}$, where the uncertainties are statistical and systematic, respectively. The significance of the $B\to K\ell^+\ell^-$ signal is over $8\sigma$, while for $B\to K^*\ell^+\ell^-$ it is $3.3\sigma$.Comment: 7 pages, 2 postscript figues, submitted to Phys. Rev. Let

Direct measurement of the pion valence quark momentum distribution, the pion light-cone wave function squared

We present the first direct measurements of the pion valence quark momentum distribution which is related to the square of the pion light-cone wave function. The measurements were carried out using data on diffractive dissociation of 500 GeV/c $\pi^-$ into di-jets from a platinum target at Fermilab experiment E791. The results show that the $|q\bar {q}>$ light-cone asymptotic wave function, which was developed using perturbative QCD methods, describes the data well for $Q^2 \sim 10 ~{\rm (GeV/c)^2}$ or more. We also measured the transverse momentum distribution of the diffractive di-jets.Comment: 13 pages, 4 figure

Measurement of the branching ratios of the Z0 into heavy quarks

We measure the hadronic branching ratios of the Z0 boson into heavy quarks: Rb=Gamma(Z0->bb)/Gamma(Z0->hadrons) and Rc=Gamma(Z0->cc/Gamma(Z0->hadrons) using a multi-tag technique. The measurement was performed using about 400,000 hadronic Z0 events recorded in the SLD experiment at SLAC between 1996 and 1998. The small and stable SLC beam spot and the CCD-based vertex detector were used to reconstruct bottom and charm hadron decay vertices with high efficiency and purity, which enables us to measure most efficiencies from data. We obtain, Rb=0.21604 +- 0.00098(stat.) +- 0.00073(syst.) -+ 0.00012(Rc) and, Rc= 0.1744 +- 0.0031(stat.) +- 0.0020(syst.) -+ 0.0006(Rb)Comment: 37 pages, 8 figures, to be submitted to Phys. Rev. D version 2: changed title to ratios, used common D production fractions for Rb and Rc and corrected Zgamma interference. Identical to PRD submissio