P. Hurst

The Collider Detector at Fermilab (CDF) is a 5000 t magnetic detector built to study 2 TeV pp collisions at the Fermilab Tevatron. Event analysis is based on charged particle tracking, magnetic momentum analysis and fine-grained calorimetry. The combined electromagnetic and hadron calorimetry has approximately uniform granularity in rapidity-azimuthal angle and extends down to 2° from the beam direction. Various tracking chambers cover the calorimeter acceptance and extend charged particle tracking down to 2 mrad from the beam direction. Charged particle momenta are analyzed in a 1.5 T solenoidal magnetic field, generated by a superconducting coil which is 3 m in diameter and 5 m in length. The central tracking chamber measures particle momenta with a resolution better then δpT/pT2 = 2 × 10−3 (GeV/c)−1 in the region 40° < θ < 140° and δPT/pT2 ≤ 4 × 10−3 for 21° < θ < 40° and 140° < θ < 159°. The calorimetry, which has polar angle coverage from 2° to 178° and full azimuthal coverage, consists of electromagnetic shower counters and hadron calorimeters, and is segmented into about 5000 projective “towers” or solid angle elements. Muon coverage is provided by drift chambers in the region 56° < θ < 124°, and by large forward toroid systems in the range 3° < θ < 16° and 164° < θ < 177°. Isolated high momentum muons can be identified in the intermediate angular range by a comparison of the tracking and calorimeter information in many cases. A custom front-end electronics system followed by a large Fastbus network provides the readout of the approximately 100 000 detector channels. Fast Level 1 and Level 2 triggers make a detailed pre-analysis of calorimetry and tracking information; a Level 3 system of on-line processors will do parallel processing of events. This paper provides a summary of the aspects of the detector which are relevant to its physics capabilities, with references to more detailed descriptions of the subsystems.

We have studied the muon neutrino and antineutrino quasi-elastic (QEL) scattering reactions (ν μ n→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 ν μ ( $\bar{\nu}_{\mu}$ ) 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 M A was extracted from the measured quasi-elastic neutrino cross section. The corresponding result is M A =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 Q 2 shape analysis of the high purity sample of ν μ quasi-elastic 2-track events, but has smaller systematic error and should be quoted as the main result of this work. Our measured M A is found to be in good agreement with the world average value obtained in previous deuterium filled bubble chamber experiments. The NOMAD measurement of M A is lower than those recently published by K2K and MiniBooNE Collaborations. However, within the large errors quoted by these experiments on M A , these results are compatible with the more precise NOMAD value.

We present measurements of the pseudorapidity (η) distribution of charged particles (dNchdη) produced within |η|≤3.5 in proton-antiproton collisions at √s of 630 and 1800 GeV. We measure dNchdη at η=0 to be 3.18±0.06(stat)±0.10(syst) at 630 GeV, and 3.95±0.03 (stat)±0.13(syst) at 1800 GeV. Many systematic errors in the ratio of dNchdη at the two energies cancel, and we measure 1.26±0.01±0.04 for the ratio of dNchdη at 1800 GeV to that at 630 GeV within |η|≤3. Comparing to lower-energy data, we observe an increase faster than ln(s) in dNchdη at η=0.Received 2 October 1989DOI:https://doi.org/10.1103/PhysRevD.41.2330©1990 American Physical Society

Measurements of inclusive transverse-momentum spectra for charged particles produced in proton-antiproton collisions at \ensuremath{\surd}2 of 630 and 1800 GeV are presented and compared with data taken at lower energies.

We present the results of a search for νμ→νe oscillations in the NOMAD experiment at CERN. The experiment looked for the appearance of νe in a predominantly νμ wide-band neutrino beam at the CERN SPS. No evidence for oscillations was found. The 90% confidence limits obtained are Δm2<0.4 eV2 for maximal mixing and sin2(2θ)<1.4×10−3 for large Δm2. This result excludes the LSND allowed region of oscillation parameters with Δm2≳10 eV2.

A search for the top quark in p\ifmmode\bar\else\textasciimacron\fi{}p collisions at a center-of-mass energy of 1.8 TeV using the Collider Detector at Fermilab is described. A study of events selected by requiring an energetic electron, missing transverse energy, and two or more jets excludes at 95% confidence level the standard-model production and decay of tt\ifmmode\bar\else\textasciimacron\fi{} pairs if the top-quark mass is between 40 and 77 GeV/${c}^{2}$. The observed electron + multijet data are consistent with W-boson production.

The NOMAD experiment is a short base-line search for νμ − ντ oscillations in the CERN neutrino beam. The ντ's are searched for through their charged current interactions followed by the observation of the resulting τ− through its electronic, muonic or hadronic decays. These decays are recognized using kinematical criteria necessitating the use of a light target which enables the reconstruction of individual particles produced in the neutrino interactions. This paper describes the various components of the NOMAD detector: the target and muon drift chambers, the electromagnetic and hadronic calorimeters, the preshower and transition radiation detectors and the veto and trigger scintillation counters. The beam and data acquisition system are also described. The quality of the reconstruction and individual particles is demonstrated through the ability of NOMAD to observe Ks0's, Λ0's and π0's. Finally, the observation of τ− through its electronic decay being one of the most promising channels in the search, the identification of electrons in NOMAD is discussed.

We have determined mW=79.91±0.39 GeV/c2 from an analysis of W→eν and W→μν data from the Collider Detector at Fermilab in p¯p collisions at a c.m. energy of √s =1.8 TeV. This result, together with the world-average Z mass, determines the weak mixing angle to be sin2θW=0.232±0.008. Bounds on the top-quark mass are discussed.Received 13 August 1990DOI:https://doi.org/10.1103/PhysRevLett.65.2243©1990 American Physical Society

An analysis of pp\ifmmode\bar\else\textasciimacron\fi{} collision events at \ensuremath{\surd}s =1.8 TeV with jets and large missing transverse energy finds no event with missing transverse energy &gt;40 GeV. This result yields a 90%-C.L. limit on the cross section for one-jet-event production of &lt;0.1 nb for events with the jet in the pseudorapidity range \ensuremath{\Vert}\ensuremath{\eta}\ensuremath{\Vert}&lt;1.0 and with jet ${E}_{T}$&gt;52 GeV. Limits on the masses of squarks and gluinos in a minimal supersymmetry model are also set. At the 90% C.L., ${m}_{q\ifmmode \tilde{}\else \~{}\fi{}}$&gt;74 GeV and ${m}_{g\ifmmode \tilde{}\else \~{}\fi{}}$&gt;73 GeV.

In order to avoid self-interference, Simultaneous Transmit And Receive (STAR) systems require low mutual coupling between their respective transmit and receive antennas. This paper discusses the development of an 8-element transmit ring array antenna on a circular ground plane with a raised receive element. When combined with a beamformer that supplies linear progressive phase shifts to the array with opposing elements phased 180-degrees apart, the receive and transmit antennas are measured to exhibit 55 dB of isolation and omni-directional patterns in the 2.4 to 2.5 GHz band.

We report on a search for heavy neutrinos ($\nus$) produced in the decay $D_s\to τ\nus$ at the SPS proton target followed by the decay $\nudecay$ in the NOMAD detector. Both decays are expected to occur if $\nus$ is a component of $ν_τ$.\ From the analysis of the data collected during the 1996-1998 runs with $4.1\times10^{19}$ protons on target, a single candidate event consistent with background expectations was found. This allows to derive an upper limit on the mixing strength between the heavy neutrino and the tau neutrino in the $\nus$ mass range from 10 to 190 $\rm MeV$. Windows between the SN1987a and Big Bang Nucleosynthesis lower limits and our result are still open for future experimental searches. The results obtained are used to constrain an interpretation of the time anomaly observed in the KARMEN1 detector.\

Results from the ντ appearance search in a neutrino beam using the full NOMAD data sample are reported. A new analysis unifies all the hadronic τ decays, significantly improving the overall sensitivity of the experiment to oscillations. The “blind analysis” of all topologies yields no evidence for an oscillation signal. In the two-family oscillation scenario, this sets a 90% CL allowed region in the sin22θμτ–Δm2 plane which includes sin22θμτ<3.3×10−4 at large Δm2 and Δm2< 0.7 eV2/c4 at sin22θμτ=1. The corresponding contour in the νe→ντ oscillation hypothesis results in sin22θeτ<1.5×10−2 at large Δm2 and Δm2<5.9 eV2/c4 at sin22θeτ=1. We also derive limits on effective couplings of the τ lepton to νμ or νe.

A search for tt\ifmmode\bar\else\textasciimacron\fi{}\ensuremath{\rightarrow}e\ensuremath{\mu}+X in pp\ifmmode\bar\else\textasciimacron\fi{} collisions at s\ensuremath{\surd}\ifmmode\bar\else\textasciimacron\fi{} TeV is described. The production and decay of top-quark--antiquark pairs is considered in the context of the standard model. The analysis is based on data with an integrated luminosity of 4.4 ${\mathrm{pb}}^{\mathrm{\ensuremath{-}}1}$ recorded with the Collider Detector at Fermilab. An upper limit on the tt\ifmmode\bar\else\textasciimacron\fi{} cross section is obtained, and the top quark in the mass range 28--72 GeV/${c}^{2}$ is excluded at the 95% C.L. The same limits apply to a possible fourth-generation, charge -(1/3, b' quark, decaying via the charged current.

We have determined mW=79.91±0.39 GeV/c2 from an analysis of W→eν and W→μν data from the Collider Detector at Fermilab in ¯pp collisions at √s=1.8 TeV. From this result and the world-average Z mass, the weak mixing angle is determined to be sin2θW=0.232±0.008. An upper bound on the top-quark mass derived from this result is discussed.Received 13 August 1990DOI:https://doi.org/10.1103/PhysRevD.43.2070©1991 American Physical Society

An analysis of ${Z}^{0}$\ensuremath{\rightarrow}${e}^{+}$${e}^{\mathrm{\ensuremath{-}}}$ and ${Z}^{0}$\ensuremath{\rightarrow}${\ensuremath{\mu}}^{+}$${\ensuremath{\mu}}^{\mathrm{\ensuremath{-}}}$ data from the Collider Detector at Fermilab in p\ifmmode\bar\else\textasciimacron\fi{}p collisions at \ensuremath{\surd}s =1.8 TeV yields a mass of the ${Z}^{0}$ boson of ${M}_{Z}$=90.9\ifmmode\pm\else\textpm\fi{}0.3 (stat+syst)\ifmmode\pm\else\textpm\fi{}0.2 (scale) GeV/${c}^{2}$ and a width of ${\ensuremath{\Gamma}}_{z}$=3.8\ifmmode\pm\else\textpm\fi{}0.8\ifmmode\pm\else\textpm\fi{}1.0 GeV.

We present a measurement of the muon neutrino–nucleon inclusive charged current cross section, off an isoscalar target, in the neutrino energy range 2.5⩽Eν⩽40GeV. The significance of this measurement is its precision, ±4% in 2.5⩽Eν⩽10GeV, and ±2.6% in 10⩽Eν⩽40GeV regions, where significant uncertainties in previous experiments still exist, and its importance to the current and proposed long baseline neutrino oscillation experiments.

We present our new measurement of the cross-section for charm dimuon production in neutrino–iron interactions based upon the full statistics collected by the NOMAD experiment. After background subtraction we observe 15 344 charm dimuon events, providing the largest sample currently available. The analysis exploits the large inclusive charged current sample – about 9×106 events after all analysis cuts – and the high resolution NOMAD detector to constrain the total systematic uncertainty on the ratio of charm dimuon to inclusive Charged Current (CC) cross-sections to ∼2%. We also perform a fit to the NOMAD data to extract the charm production parameters and the strange quark sea content of the nucleon within the NLO QCD approximation. We obtain a value of mc(mc)=1.159±0.075 GeV/c2 for the running mass of the charm quark in the MS¯ scheme and a strange quark sea suppression factor of κs=0.591±0.019 at Q2=20 GeV2/c2.

The Λ polarization in νμ charged current interactions has been measured in the NOMAD experiment. The event sample (8087 reconstructed Λ 's) is more than an order of magnitude larger than that of previous bubble chamber experiments, while the quality of event reconstruction is comparable. We observe negative polarization along the W -boson direction which is enhanced in the target fragmentation region: Px(xF<0)=−0.21±0.04(stat)±0.02(sys) . In the current fragmentation region we find Px(xF>0)=−0.09±0.06(stat)±0.03(sys) . These results provide a test of different models describing the nucleon spin composition and the spin transfer mechanisms. A significant transverse polarization (in the direction orthogonal to the Λ production plane) has been observed for the first time in a neutrino experiment: Py=−0.22±0.03(stat)±0.01(sys) . The dependence of the absolute value of Py on the Λ transverse momentum with respect to the hadronic jet direction is in qualitative agreement with the results from unpolarized hadron–hadron experiments.

Inclusive jet production at $\sqrt{s}=1.8$ TeV has been measured in the CDF detector at the Fermilab Tevatron $\overline{p}p$ Collider. Jets with transverse energies (${E}_{t}$) up to 250 GeV have been observed. The ${E}_{t}$ dependence of the inclusive jet cross section is consistent with leading-order quantum-chromodynamic calculations, and comparison with lower-energy data shows deviations from scaling consistent with QCD. A lower limit of 700 GeV (95% confidence level) is placed on the quark compositeness scale parameter ${\ensuremath{\Lambda}}_{c}$ associated with an effective contact interaction.

An analysis of high-transverse-momentum electrons using data from the Collider Detector at Fermilab (CDF) of ¯pp collisions at √s=1800 GeV yields values of the production cross section times branching ratio for W and Z0 bosons of σ(¯pp→WX→eνX)=2.19±0.04(stat)±0.21(syst) nb and σ(¯pp→Z0X→e+e−X)=0.209±0.013(stat)±0.017(syst) nb. Detailed descriptions of the CDF electron identification, background, efficiency, and acceptance are included. Theoretical predictions of the cross sections that include a mass for the top quark larger than the W mass, current values of the W and Z0 masses, and higher-order QCD corrections are in good agreement with these measured values.Received 13 November 1990DOI:https://doi.org/10.1103/PhysRevD.44.29©1991 American Physical Society

NOMAD is a neutrino oscillation experiment designed to search for ντ appearance in the CERN-SPS wide band νμ beam. Signal detection relies on the identification of ντ charged current interactions using kinematic criteria. The analysis of the 1995 data sample yields no oscillation signal. Combining all studied τ decay modes, a limit of sin22θμτ<4.2×10−3 is obtained for large Δm2 at the 90% confidence level.

The method developed for the calculation of the flux and composition of the West Area Neutrino Beam used by NOMAD in its search for neutrino oscillations is described. The calculation is based on particle production rates computed using a recent version of FLUKA and modified to take into account the cross-sections measured by the SPY and NA20 experiments. These particles are propagated through the beam line taking into account the material and magnetic fields they traverse. The neutrinos produced through their decays are tracked to the NOMAD detector. The fluxes of the four neutrino flavours at NOMAD are predicted with an uncertainty of about 8% for νμ and νe, 10% for ν̄μ, and 12% for ν̄e. The energy-dependent uncertainty achieved on the νe/νμ prediction needed for a νμ→νe oscillation search ranges from 4% to 7%, whereas the overall normalization uncertainty on this ratio is 4.2%.

The NOMAD Collaboration presents a study of opposite sign dimuon events in the framework of Leading Order QCD. A total of 2714 neutrino- and 115 antineutrino-induced opposite sign dimuon events with Eμ1,Eμ2>4.5 GeV, 15<Eν<300 GeV and Q2>1(GeV/c)2 are observed in the Front-Calorimeter of NOMAD during the 1995 and 1996 runs. The analysis yields a value for the charm quark mass of mc=1.3+0.3+0.3−0.3−0.3GeV/c2 and for the average semileptonic branching ratio of Bc=0.095+0.007+0.014−0.007−0.013. The ratio of the strange to non-strange sea in the nucleon is measured to be κ=0.48+0.09+0.17−0.07−0.12. The measured rate of charm-induced dimuon relative to single muon, as a function of neutrino energy, is consistent with the slow rescaling hypothesis of heavy quark production.

We present the dijet invariant-mass distribution in the region between 60 and 500 GeV, measured in 1.8-TeV $\overline{p}p$ collisions in the Collider Detector at Fermilab. Jets are restricted to the pseudorapidity interval $|\ensuremath{\eta}|&lt;0.7$. Data are compared with QCD calculations; axigluons are excluded with 95% confidence in the region $120&lt;{M}_{A}&lt;210$ GeV for axigluon width ${\ensuremath{\Gamma}}_{A}=\frac{N{\ensuremath{\alpha}}_{s}{M}_{A}}{6}$, with $N=5$.

A search for the top quark in p¯p collisions at a center-of-mass energy of 1.8 TeV using the Collider Detector at Fermilab is described. A study of events selected by requiring an energetic electron, missing transverse energy, and two or more jets excludes at 95% confidence level the standardmodel production and decay of tt¯ pairs if the top-quark mass is between 40 and 77 GeV/c2. The observed electron+multijet data are consistent with W-boson production.Received 12 July 1990DOI:https://doi.org/10.1103/PhysRevD.43.664©1991 American Physical Society

Using the Collider Detector at Fermilab, the W-boson differential cross section d\ensuremath{\sigma}/${\mathit{dP}}_{\mathit{T}}$ is measured using W\ensuremath{\rightarrow}e\ensuremath{\nu} events in proton-antiproton collisions at \ensuremath{\surd}s =1.8 TeV. A next-to-leading-order theoretical calculation agrees well with the data. The cross section (\ensuremath{\sigma}) for ${\mathit{P}}_{\mathit{T}}$&gt;50 GeV/c is measured to be 423\ifmmode\pm\else\textpm\fi{}58(stat)\ifmmode\pm\else\textpm\fi{}108(syst) pb.

We present a study of exclusive neutral pion production in neutrino-nucleus Neutral Current interactions using data from the NOMAD experiment at the CERN SPS. The data correspond to $1.44 \times 10^6$ muon-neutrino Charged Current interactions in the energy range $2.5 \leq E_{\nu} \leq 300$ GeV. Neutrino events with only one visible $\pi^0$ in the final state are expected to result from two Neutral Current processes: coherent $\pi^0$ production, {\boldmath $\nu + {\cal A} \to \nu + {\cal A} + \pi^0$} and single $\pi^0$ production in neutrino-nucleon scattering. The signature of coherent $\pi^0$ production is an emergent $\pi^0$ almost collinear with the incident neutrino while $\pi^0$'s produced in neutrino-nucleon deep inelastic scattering have larger transverse momenta. In this analysis all relevant backgrounds to the coherent $\pi^0$ production signal are measured using data themselves. Having determined the backgrounds, and using the Rein-Sehgal model for the coherent $\pi^0$ production to compute the detection efficiency, we obtain {\boldmath $4630 \pm 522 (stat) \pm 426 (syst)$} corrected coherent-$\pi^0$ events with $E_{\pi^0} \geq 0.5$ GeV. We measure {\boldmath $\sigma (\nu {\cal A} \to \nu {\cal A} \pi^0) = [ 72.6 \pm 8.1(stat) \pm 6.9(syst) ] \times 10^{-40} cm^2/nucleus$}. This is the most precise measurement of the coherent $\pi^0$ production to date.

We present a search for neutrino induced events containing a single, exclusive photon using data from the NOMAD experiment at the CERN SPS where the average energy of the neutrino flux is ≃25GeV. The search is motivated by an excess of electron-like events in the 200–475 MeV energy region as reported by the MiniBooNE experiment. In NOMAD, photons are identified via their conversion to e+e− in an active target embedded in a magnetic field. The background to the single photon signal is dominated by the asymmetric decay of neutral pions produced either in a coherent neutrino–nucleus interaction, or in a neutrino–nucleon neutral current deep inelastic scattering, or in an interaction occurring outside the fiducial volume. All three backgrounds are determined in situ using control data samples prior to opening the 'signal-box'. In the signal region, we observe 155 events with a predicted background of 129.2±8.5±3.3. We interpret this as null evidence for excess of single photon events, and set a limit. Assuming that the hypothetical single photon has a momentum distribution similar to that of a photon from the coherent π0 decay, the measurement yields an upper limit on single photon events, <4.0×10−4 per νμ charged current event. Narrowing the search to events where the photon is approximately collinear with the incident neutrino, we observe 78 events with a predicted background of 76.6±4.9±1.9 yielding a more stringent upper limit, <1.6×10−4 per νμ charged current event.

Citation Brunelle, John, Peter Hurst, John Huth, Laura Kang, Chaki Ng, David C. Parkes, Margo Seltzer, Jim Shank, and Saul Youssef. 2006. Egg: An extensible and economics-inspired open grid computing platform. In GECON 2006: Proceedings of the 3rd International Workshop on Grid Economics and Business Models, Singapore, 16 May 2006, ed. H. Lee, and S. Miller. Singapore; Hackensack, NJ: World Scientific.

A search was made for a new light gauge boson X which might be produced in π0→γ+X decay from neutral pions generated by 450 GeV protons in the CERN SPS neutrino target. The X's would penetrate the downstream shielding and be observed in the NOMAD detector via the Primakoff effect, in the process of X→π0 conversion in the external Coulomb field of a nucleus. With 1.45×1018 protons on target, 20 candidate events with energy between 8 and 140 GeV were found from the analysis of neutrino data. This number is in agreement with the expectation of 18.1±2.8 background events from standard neutrino processes. A new 90 %C.L. upper limit on the branching ratio Br(π0→γ+X)< (3.3 to 1.9)×10−5 for X masses ranging from 0 to 120 MeV/c2 is obtained.

With additional data and improved algorithms, we have enhanced the sensitivity of our appearance search for νμ→ντ oscillations in the NOMAD detector in the CERN-SPS wide-band neutrino beam. The search uses kinematic criteria to identify ντ charged current interactions followed by decay of the τ− to one of several decay modes. Our “blind” analyses of deep-inelastic scattering data taken in 1996 and 1997, combined with consistent reanalyses of previously reported 1995 data, yield no oscillation signal. For the two-family oscillation scenario, we present the contour outlining a 90% C.L. confidence region in the sin22θμτ–Δm2 plane. At large Δm2, the confidence region includes sin22θμτ<1.2×10−3 (a limit 3.5 times more stringent than in our previous publication), while at sin22θμτ=1, the confidence region includes Δm2<1.2 eV2/c4.

Traditionally, magnetic materials have been metals or, if inorganic compounds such as oxides, of continuous lattice type. However, in recent years chemists have synthesized increasing numbers of crystalline solids based on molecular building blocks in the form of coordination and organometallic complexes or purely organic molecules, which exhibit spontaneous magnetization. In striking contrast to conventional magnets, these materials are made from solutions close to room temperature rather than by metallurgical or ceramic methods. This book, which originates from contributions to a Discussion Meeting of The Royal Society of London, brings together many of the leading international practitioners in the field, who survey their own recent work and place it in the context of the wider fields of magnetism and supramolecular chemistry. All aspects of molecular-based magnets are addressed, including synthesis, structure-property relations and physical properties. Contents include details of the characterization of the first purely organic ferromagnet, the synthesis of high coercivity materials and a unique description of new materials with Curie temperatures well above ambient. A coherent survey of this rapidly developing field for the more general reader, Metal-Organic and Organic Molecular Magnets will also be welcomed by researchers and lecturers in materials science and inorganic or solid state chemistry.

We present a measurement of the polarization of Λ̄ hyperons produced in νμ charged current interactions. The full data sample from the NOMAD experiment has been analyzed using the same V0 identification procedure and analysis method reported in a previous paper [NOMAD Collaboration, Nucl. Phys. B 588 (2000) 3] for the case of Λ hyperons. The Λ̄ polarization has been measured for the first time in a neutrino experiment. The polarization vector is found to be compatible with zero.

We have measured the cross section as a function of invariant mass for isolated electron pairs produced in p¯p collisions at s=1.8 TeV for pair masses M>30 GeV/c2. We find good agreement between the measured distribution and the standard-model prediction for the Drell-Yan production mechanism. Additional heavy neutral vector bosons (Z′) are excluded for MZ'<387 GeV/c2 (95% confidence level) assuming standard-model couplings. A lower limit of 2.2 TeV (95% confidence level) is placed on the electron-quark compositeness scale parameter Λ−LL associated with an effective contact interaction.Received 16 July 1991DOI:https://doi.org/10.1103/PhysRevLett.67.2418©1991 American Physical Society

A study of strange particle production in νμ charged current interactions has been performed using the data from the NOMAD experiment. Yields of neutral strange particles (K0s,Λ,Λ̄) have been measured. Mean multiplicities are reported as a function of the event kinematic variables Eν, W2 and Q2 as well as of the variables describing particle behaviour within a hadronic jet: xF, z and pT2. Decays of resonances and heavy hyperons with identified K0s and Λ in the final state have been analyzed. Clear signals corresponding to K★±, Σ★±, Ξ− and Σ0 have been observed.

An analysis of W- and Z-boson production using data from the Collider Detector at Fermilab at \ensuremath{\surd}s =1.8 TeV yields \ensuremath{\sigma}(W\ensuremath{\rightarrow}ev)/\ensuremath{\sigma}(Z\ensuremath{\rightarrow}ee)=10.2\ifmmode\pm\else\textpm\fi{}0.8(stat)\ifmmode\pm\else\textpm\fi{}0.4(syst). The width of the W boson, \ensuremath{\Gamma}(W), and a limit on the top-quark mass independent of decay mode are extracted from this measurement.

The cross section for the production and subsequent decay to electron and neutrino of the W intermediate vector boson has been measured in 1.8-TeV p\ifmmode\bar\else\textasciimacron\fi{}p collisions at the Fermilab Tevatron Collider. An analysis of events with missing transverse energy greater than 25 GeV and with an electron of transverse energy greater than 15 GeV from a datum sample of 25.3 ${\mathrm{nb}}^{\mathrm{\ensuremath{-}}1}$ gives \ensuremath{\sigma}B=2.6\ifmmode\pm\else\textpm\fi{}0.6\ifmmode\pm\else\textpm\fi{}0.5 nb.

Practical ultrawideband phased array technology used in airborne and ground-based systems applications.Ultrawideband phased array antennas are an enabling technology for many ground-based and airborne communications and radar systems. This book surveys electromagnetic theory and phased array antenna theory and provides examples of ultrawideband phased array antenna technology. It describes some of the research on ultrawideband phased arrays undertaken by the authors and their colleagues at MIT Lincoln Laboratory over the last ten years. The book focuses on experimental prototype ultrawideband phased array technology developed at Lincoln Laboratory for applications in the VHF and UHF bands from approximately 100 MHz to 1 GHz, and addresses dipole, monopole, loop, and other antenna array elements. It offers examples of antennas for both airborne and ground vehicle applications. Most of the examples are developed in the context of rapid prototyping for quick assessment of communications and radar systems feasibility, with measurements and numerical electromagnetic simulation results provided for many prototype examples. The book is intended primarily for practicing antenna engineers, radar engineers, and communications engineers, and for graduate students and researchers in electrical engineering. Readers need no prior knowledge of ultrawideband antennas, although some background in electromagnetic theory, antennas, radar, and communications would be helpful.

The charged-particle fractional momentum distribution within jets, D(z), has been measured in dijet events from 1.8-TeV p\ifmmode\bar\else\textasciimacron\fi{}p collisions in the Collider Detector at Fermilab. As expected from scale breaking in quantum chromodynamics, the fragmentation function D(z) falls more steeply as dijet invariant mass increases from 60 to 200 GeV/${\mathit{c}}^{2}$. The average fraction of the jet momentum carried by charged particles is 0.65\ifmmode\pm\else\textpm\fi{}0.02(stat)\ifmmode\pm\else\textpm\fi{}0.08(syst).

A search was made for heavy stable charged particles produced in 1.8-TeV proton-antiproton collisions. No such particles were found in 26.2 ${\mathrm{nb}}^{\mathrm{\ensuremath{-}}1}$ of data. Cross-section limits are presented and mass limits of the order of 100 GeV are set for particles containing excited quarks in higher color representations.

We have measured dijet angular distributions at \ensuremath{\surd}s =1.8 TeV with the Collider Detector at Fermilab and the Tevatron p\ifmmode\bar\else\textasciimacron\fi{}p Collider and find agreement with leading-order QCD. By comparing the distribution for the highest dijet invariant masses with the prediction of a model of quark compositeness, we set a lower limit on the associated scale parameter ${\ensuremath{\Lambda}}_{c}$ at 330 GeV (95% C.L.).

Many in-band full-duplex (IBFD) applications require omnidirectional radiation coverage in addition to multilayered self-interference cancellation (SIC). While system-level SIC approaches often require high-isolation antennas before implementing analog and/or digital methods, maintaining the desired omnidirectional transmit/receive patterns is difficult for compact designs that utilize the same polarization. This article discusses the concept development and design progression of the circular mode phasing technique applied to omnidirectional IBFD antenna arrays. The theoretical fundamentals are presented along with simulation results and then validated through the discussion of two prototype antennas, which were measured to provide up to 60 dB of isolation over 2.4–2.5 GHz, which is the highest reported for this SIC method. Additionally, the evolution of this concept for a collection of measured prototypes is summarized and characterized with a unique figure of merit, which should help advance the application of this technique within future IBFD systems.

Measurements of inclusive transverse-momentum spectra for ${K}_{S}^{0}$ mesons produced in proton-antiproton collisions at $\sqrt{s}$ of 630 and 1800 GeV are presented and compared with data taken at lower energies. The ratio, as a function of ${p}_{T}$, of the cross section for ${K}_{S}^{0}$ to that for charged hadrons is very similar to what is observed at lower energies. At 1800 GeV, we calculate the strangeness-suppression factor $\ensuremath{\lambda}=0.40\ifmmode\pm\else\textpm\fi{}0.05$.

ŽWe carried out a model-independent search for light scalar or pseudoscalar particles a's an example of which is the .axion that couple to two photons by using a photon-regeneration method at high energies allowing a substantial increase in the sensitivity to eV masses.The experimental set-up is based on elements of the CERN West Area Neutrino Facility Ž .WANF beam line and the NOMAD neutrino detector.The new particles, if they exist, could be produced through the Primakoff effect in interactions of high energy photons, generated by the 450 GeV protons in the CERN SPS neutrino target, with virtual photons from the WANF horn magnetic field.The particles would penetrate the downstream shielding and would be observed in the NOMAD neutrino detector through their re-conversion into real high energy photons by interacting with the virtual photons from the magnetic field of the NOMAD dipole magnet.From the analysis of the data collected during the 1996 run with 1.08 = 10 19 protons on target, 312 candidate events with energy between 5 and 140 GeV were found.This number is in general agreement with the expectation of 272 " 18 background events from standard neutrino processes.A 90 % CL upper limit on the agg-coupling g -1.5 = 10 y4 GeV y1 agg for a masses up to 40 eV is obtained.

In 2004, a combined system test was performed in the H8 beam line at the CERN SPS with a setup reproducing the geometry of sectors of the ATLAS Muon Spectrometer, formed by three stations of Monitored Drift Tubes (MDT). The full ATLAS analysis chain was used to obtain the results presented in this paper. The basic design performances of the Muon Spectrometer were verified. The stability of MDT calibration constants, the alignment system using optical devices and high energy tracks, as well as the intrinsic sagitta resolution of the Muon Spectrometer were studied and found to agree with expectations. The reconstruction of muon tracks using the combined information from both the Inner Detector and the Muon Spectrometer are also presented.

We describe sources of error in a breadboard, low-cost, time-of-flight laser rangefinder. The rangefinder deduces the range of a retroreflecting target by directing an intensity-modulated laser beam at the target and measuring the phase difference between the returned and transmitted modulation envelopes. The phase measurement is performed by a combination of heterodyning and digital signal processing. We present an equation for the standard deviation of statistical errors generated by quantization in the digital signal processing. We show how both electrical crosstalk and stray light give rise to errors which are cyclic with target range, and we describe how these errors can be reduced. We demonstrate the importance of errors caused by the dependence of the photodiode’s propagation delay upon the intensity and placement of the light spot incident upon its surface, and discuss how the instrument’s optical components can be arranged to minimize such errors. Finally, we show that our rangefinder, using a modulation frequency of 140 MHz, has rms nonlinearity less than 85 μm.

Backward proton and π− production has been studied in νμCC interactions with carbon nuclei. Detailed analyses of the momentum distributions, of the production rates, and of the general features of events with a backward going particle, have been carried out in order to understand the mechanism producing these particles. The backward proton data have been compared with the predictions of the reinteraction and the short range correlation models.

Updated results from the appearance searches for νμ→ντ and νe→ντ oscillations in the full NOMAD data sample are reported. The increased data and the use of more refined kinematic schemes for the ντ CC selection allow a significant improvement of the overall sensitivity. The “blind analysis” of both the deep-inelastic and the low multiplicity samples yields no evidence for an oscillation signal. In the two-family oscillation scenario, this sets a 90% C.L. region in the sin22θμτ−Δm2 plane which includes sin22θμτ<4.4×10−4 at large Δm2 and Δm2<0.8 eV2/c4 at sin22θμτ=1. The corresponding contour in the νe→ντ oscillation hypothesis results in sin22θeτ<2.2×10−2 at large Δm2 and Δm2<6.5 eV2/c4 at sin22θeτ=1.

The inclusive production of the meson resonances ρ0(770), f0(980) and f2(1270) in neutrino–nucleus charged current interactions has been studied with the NOMAD detector exposed to the wide band neutrino beam generated by 450 GeV protons at the CERN SPS. For the first time the f0(980) meson is observed in neutrino interactions. The statistical significance of its observation is 6 standard deviations. The presence of f2(1270) in neutrino interactions is reliably established. The average multiplicity of these three resonances is measured as a function of several kinematic variables. The experimental results are compared to the multiplicities obtained from a simulation based on the Lund model. In addition, the average multiplicity of ρ0(770) in antineutrino–nucleus interactions is measured.

A search was made among νμ charged current events collected in the NOMAD experiment for the reaction: νμ+N→μ−+D★++hadrons↪D0+π+↪K−+π+. A high purity D★+ sample composed of 35 events was extracted. The D★+ yield in νμ charged current interactions was measured to be T=(0.79±0.17(stat.)±0.10(syst.))%. The mean fraction of the hadronic jet energy taken by the D★+ is 0.67±0.02(stat.)±0.02(syst.). The distributions of the fragmentation variables z, PT2 and xF for D★+ are also presented.

A linearly-polarized ultrawideband dipole array antenna has been developed for coverage in the VHF/UHF frequency range for communications or radar applications. The antenna design utilizes a horizontally polarized array of thick tubular dipole elements above a ground plane. Numerical electromagnetic simulations were used to analyze and optimize the antenna parameters prior to fabrication. Measurements of a 24-element ultrawideband dipole array prototype in an anechoic chamber demonstrate the antenna's return loss and gain pattern performance over a wide bandwidth.

The two-jet differential cross section ${\mathit{d}}^{3}$\ensuremath{\sigma}(p\ifmmode\bar\else\textasciimacron\fi{}p\ensuremath{\rightarrow}jet 1+jet 2+X)/${\mathit{dE}}_{\mathit{t}}$d${\mathrm{\ensuremath{\eta}}}_{1}$d${\mathrm{\ensuremath{\eta}}}_{2}$, averaged over -0.6\ensuremath{\le}${\mathrm{\ensuremath{\eta}}}_{1}$\ensuremath{\le}0.6, at \ensuremath{\surd}s =1.8 TeV, has been measured in the Collider Detector at Fermilab. The predictions of leading-order quantum chromodynamics for most choices of structure functions show agreement with the data.

The production rate of charged D* mesons in jets has been measured in 1.8-TeV p¯p collisions at the Fermilab Tevatron with the Collider Detector at Fermilab. In a sample of approximately 32 300 jets with a mean transverse energy of 47 GeV obtained from an exposure of 21.1 nb−1, a signal corresponding to 25.0±7.5(stat)±2.0(syst) D*±→K∓π±π± events is seen above background. This corresponds to a ratio N(D*++D*−)/N(jet) =0.10±0.03±0.03 for D* mesons with fractional momentum z greater than 0.1.Received 10 October 1989DOI:https://doi.org/10.1103/PhysRevLett.64.348©1990 American Physical Society

In the context of a two-flavour approximation we reinterpret the published NOMAD limit on νμ→ντ oscillations in terms of νe→ντ oscillations. At 90% C.L. we obtain sin22θeτ<5.2×10−2 for large Δm2, while for sin22θeτ=1 the confidence region includes Δm2<11 eV2/c4.

A measurement of the QCD jet-broadening parameter ⟨QT⟩ is described for high-ET jet data in the central calorimeter of the Collider Detector at Fermilab. As an alternate approach to clustering analysis, this method involves the use of a global event parameter which is free from the ambiguities associated with the definition and separation of individual clusters. The parameter QT is defined as the scalar sum of the transverse momentum perpendicular to the transverse thrust axis. Parton-level QCD predictions are made for ⟨QT⟩ as a function of ET, the total transverse energy in the events, and suggest that a measurement would show a dependence on the running of the strong coupling constant αs. Comparisons are made to first-order QCD parton-level calculations, as well as to fully evolved and hadronized leading-log simulations. The data are well described by the QCD predictions.Received 25 January 1991DOI:https://doi.org/10.1103/PhysRevD.44.601©1991 American Physical Society

We report on a direct search in NOMAD for a new 33.9 MeV/c2 neutral particle (X) produced in pion decay in flight, π→μX followed by the decay X→νe+e−. Both decays are postulated to occur to explain the time anomaly observed by the KARMEN experiment. From the analysis of the data collected during the 1996–1998 runs with 4.1×1019 protons on target, a single candidate event consistent with background expectations was found. The search is sensitive to a pion branching ratio BR(π→μX)>3.7×10−15, significantly smaller than previous experimental limits.

Results of a detailed study of strange particle production in neutrino neutral current interactions are presented using the data from the NOMAD experiment. Integral yields of neutral strange particles (Ks0, Λ, Λ¯) have been measured. Decays of resonances and heavy hyperons with an identified Ks0 or Λ in the final state have been analyzed. Clear signals corresponding to K⋆± and Σ(1385)± have been observed. First results on the measurements of the Λ polarization in neutral current interactions have been obtained.

First measurements of K*(892) mesons production properties and their spin alignment in nu_mu charged current (CC) and neutral current (NC) interactions are presented. The analysis of the full data sample of the NOMAD experiment is performed in different kinematic regions. For K*+ and K*- mesons produced in nu_mu CC interactions and decaying into K0 pi+/- we have found the following yields per event: (2.6 +/- 0.2 (stat.) +/- 0.2 (syst.))% and (1.6 +/- 0.1 (stat.) +/- 0.1 (syst.))% respectively, while for the K*+ and K*- mesons produced in nu NC interactions the corresponding yields per event are: (2.5 +/- 0.3 (stat.) +/- 0.3 (syst.))% and (1.0 +/- 0.3 (stat.) +/- 0.2 (syst.))%. The results obtained for the rho00 parameter, 0.40 +/- 0.06 (stat) +/- 0.03 (syst) and 0.28 +/- 0.07 (stat) +/- 0.03 (syst) for K*+ and K*- produced in nu_mu CC interactions, are compared to theoretical predictions tuned on LEP measurements in e+e- annihilation at the Z0 pole. For K*+ mesons produced in nu NC interactions the measured rho00 parameter is 0.66 +/- 0.10 (stat) +/- 0.05 (syst).

An ultrawideband (UWB) cavity-backed resistively loaded planar dipole array antenna has been developed for the 100 to 400 MHz frequency range for ground penetrating radar applications. The antenna has been designed with a 3m aperture to perform surveys of a wide swath of ground from a moving vehicle. The performance of the UWB array is quantified by moment method simulations of the electromagnetic field penetration into lossy soil. Integration of the UWB array onto a vehicle is discussed.

An analysis of the forward-backward asymmetry in ${\mathit{Z}}^{0}$ decays using data from the Collider Detector at Fermilab at \ensuremath{\surd}s =1.8 TeV yields ${\mathit{A}}_{\mathit{F}\mathit{B}}$=[5.2\ifmmode\pm\else\textpm\fi{}5.9(stat)\ifmmode\pm\else\textpm\fi{}0.4(syst)]% and ${\mathrm{sin}}^{2}$\ensuremath{\theta}${\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}}_{\mathit{W}}$ =0.${228}_{\mathrm{\ensuremath{-}}0.015}^{+0.017}$(stat)\ifmmode\pm\else\textpm\fi{}0.002(syst).

A search for exotic Θ+ baryon via Θ+→p+K0 S decay mode in the NOMAD νμN data is reported. The special background generation procedure was developed. The proton identification criteria are tuned to maximize the sensitivity to the Θ+ signal as a function of xF which allows to study the Θ+ production mechanism. We do not observe any evidence for the Θ+ state in the NOMAD data. We provide an upper limit on Θ+ production rate at 90% CL as 2.13×10-3 per neutrino interaction.

We report the first precision measurements of the scaled momentum, the charge multiplicity, and the thrust of hadronic jets in the Breit frame in Deep Inelastic Scattering νμN and ν̄μN charged current events over the Q2 range from 1 to 100 GeV2. The neutrino data, obtained in the NOMAD experiment at the CERN SPS, extend the Q2-evolution of these parameters by two orders of magnitude, and with commensurate precision, when compared to those reported by the ep and e+e− experiments.

A low-profile dual-polarized UHF array antenna has been developed for wide field-of-view dual sector coverage in the 250 to 450 MHz frequency range for communications or radar applications. The antenna utilizes a pair of parasitically-tuned dipole arrays for horizontal polarization and a pair of parasitically-tuned monopole arrays for vertical polarization, and both arrays are mounted on a common ground plane. The thickness of the antenna is 18.2 cm. Numerical electromagnetic simulations were used to analyze and optimize the antenna parameters prior to fabrication. Measurements of the dual-polarized prototype in an anechoic chamber demonstrate the antenna's return loss and dual-polarized radiation gain pattern performance.

An ultrawideband fixed time-delay steered UHF dipole array antenna has been developed for coverage in the 300 to 450 MHz frequency range for communications or radar applications. The antenna utilizes a parasitically-tuned dipole array for linear polarization and is mounted over a ground plane. Numerical electromagnetic simulations were used to analyze and optimize the antenna parameters prior to fabrication. Measurements of the prototype antenna in an anechoic chamber demonstrate the antenna's reflection coefficient and radiation gain pattern performance.

Bose–Einstein correlations in one and two dimensions have been studied, with high statistics, in charged current muon–neutrino interaction events collected with the NOMAD detector at CERN. In one dimension the Bose–Einstein effect has been analyzed with the Goldhaber and the Kopylov–Podgoretskii phenomenological parametrizations. The Goldhaber parametrization gives the radius of the pion emission region RG=1.01±0.05(stat)+0.09−0.06(sys) fm and for the chaoticity parameter the value λ=0.40±0.03(stat)+0.01−0.06(sys). Using the Kopylov–Podgoretskii parametrization yields RKP=2.07±0.04(stat)+0.01−0.14(sys) fm and λKP=0.29±0.06(stat)+0.01−0.04(sys). Different parametrizations of the long-range correlations have been also studied. The two-dimensional shape of the source has been investigated in the longitudinal comoving frame. A significant difference between the transverse and the longitudinal dimensions is observed. The high statistics of the collected sample allowed the study of the Bose–Einstein correlations as a function of rapidity, charged particle multiplicity and hadronic energy. A weak dependence of both radius and chaoticity on multiplicity and hadronic energy is found.

The modeling and validation of a 33 GHz shaped dielectric antenna design is investigated. The electromagnetic modeling was performed in both WIPL-D and FEKO, and was used to validate the antenna design prior to fabrication of the lens. It is shown that both WIPL-D and FEKO yield similarly accurate results as compared to measured far-field gain radiation patterns.

We have searched for a light standard-model Higgs boson produced in association with an intermediate vector boson at the Fermilab proton-antiproton collider operating at a center-of-mass energy of 1.8 TeV. The search was made by looking for an excess of isolated high-transverse-momentum charged-track pairs in $W$ and $Z$ events. A Higgs boson with a mass ${m}_{H}$ in the intervals $2{m}_{\ensuremath{\mu}}&lt;{m}_{H}&lt;818$ MeV/${\mathit{c}}^{2}$, and $846 \frac{\mathrm{MeV}}{{c}^{2}}&lt;{m}_{H}&lt;2{m}_{K}$ is excluded at 90% C.L.

Antenna radiation patterns are typically measured using network analyzers, which are both expensive and physically large in size. These drawbacks can limit this test equipment's usage in universities that cannot afford to make such a purchase, as well as within applications that require mobile antenna measurements. An alternative approach is to combine a low-cost receiver with a flexible signal source. This paper presents the design of a tunable comb generator prototype that is capable of outputting frequencies up to 4 GHz. The compact nature of this source along with its potential to be dynamically reconfigured yields a device that can be used to measure antenna patterns for many different applications.

This chapter contains sections titled: 8.1 Introduction, 8.2 Array Design and Fabrication, 8.3 Measured Results, 8.4 Summary, References

Value added waste sludges from biorefinery processes are as yet untapped valuable feedstocks that can be reformed into clean, high quality solid fuels. By water washing sludges produced from base hydrolyzed waste, a material stripped of water-soluble alkali and alkaline earth metals (ash) can be obtained. This work shows how leached bagasse, barley and wheat straw sludges can be valorized into clean, low ash solid biofuels that can be used to supplement global energy demands. Repurposed sludges of 1.00-2.00 mm particle size feedstocks were found to exhibit calorific values for bagasse, wheat and barley straw sludges of +17.3%, +16.8% and +11.7%, respectively, higher than the untreated waste. Additionally, by employing densification in the absence of a binder, <0.25 mm particles of leached sludge feedstocks were found to experience 16.0% (bagasse), 12.0% (wheat) and 4.0% (barley) increase to their calorific values. This provides options for sustained energy-waste production and consumption campaigns, diversifying feedstock options.

Robust and repeatable electromagnetic interference and compliance (EMI/C) measurements require specialized test equipment and adherence to a rigorous set of procedures corresponding to the necessary standard. In this work, we describe the EMI/C testing capabilities at the RF Systems Test Facility at MIT Lincoln Laboratory and share the findings from work done in accordance to MIL-STD-461G. Both conducted and radiated emissions were measured on an example RF test artifact in the large near-field anechoic chamber at the facility. CE102, CE106, and RE102 test setups and results are discussed.

This chapter deals with construction litigation as the litigation of claims by or against contractors, sub-contractors, and construction professionals that usually takes place in the Technology and Construction Court (TCC). It explains that the TCC is a branch of the Queen’s Bench Division of the High Court. It also mentions the TCC Guide that provides guidance as to the practices of the court and sets out information specific to proceedings in the TCC. This chapter cites rule 60.1(2) of the Civil Procedure Rules, which identifies a claim heard in the TCC as a ‘TCC claim’ that involves issues or questions that are technically complex. It looks at the non-exhaustive list of the categories of cases tried by the TCC that is set out in the Practice Direction.

We present the first measurement of the jet pseudorapidity distribution in direct photon events from a sample of p{bar p} collisions at {radical} (s) =1.8TeV, recorded with the Collider Detector at Fermilab. Quantum chromodynamics (QCD) predicts that these events are primarily from hard quark-gluon Compton scattering, qg{r_arrow}q{gamma}, with the final state quark producing the jet of hadrons. The jet pseudorapidity distribution in this model is sensitive to parton momentum fractions between 0.015 and 0.15. We find that the shape of the measured pseudorapidity distribution agrees well with next-to-leading order QCD calculations. {copyright} {ital 1997} {ital The American Physical Society}

An analysis of the fonvard-backward asymmetry in $Z^0$ decays using data from the Collider Detector at Fermilab provides a measurement of $sin^2 \bar{\theta}B_w$. The forward-backward asymmetry is measured to be (5.2 ± 5.9 (stat)± 0.4 (sys))%, which implies $sin^2 \bar{\theta}_w$ = 0.228 $^{+0.017}_{-0.015}$(stat)± 0.002 (sys), after QCD, QED, and weak corrections. vVhen higher order weak corrections are included, the measured value of $sin^2 \theta_w$ is consistent with previous measurements over a broad range of top quark masses