The diiractive production of 0 (770) mesons in muon-proton interactions is studied in the kinematic region 0.15 GeV 2 < Q 2 < 20 GeV 2 and 20 GeV < < 420 GeV. The data were obtained in the Fermilab xed-target experiment E665 with primary muons of 470 GeV energy. Results are presented on the Q 2 , x and dependence of the cross section, on the shape of the + ? mass spectrum, on the slope of the diiraction peak and on the production and decay angular distributions of the 0 (770). The cross section for diiractive production of 0 by virtual photons on protons depends mainly on Q 2. At xed Q 2 , no signiicant dependence on x or is observed. The extrapolation to Q 2 = 0 yields a photoproduction cross section of (10:30 0:33) b. The slope of the t 0 distribution has a value of (7:00:2) GeV ?2 , with a tendency to decrease as Q 2 increases. The production and decay angular distributions of the 0 depend strongly on Q 2 and are consistent with s-channel helicity conservation. The ratio R = L == T deduced from the decay angular distributions rises strongly with Q 2 , passing the value of 1 at Q 2 2 GeV 2 .

The drift tube production facility that we developed for producing precision drift tubes of the ATLAS forward muon system in our laboratory is described in this paper. The results of quality assurance for approximately 30,000 tube produced are given. Our experience shows that this production facility is very efficient and the quality of produced drift tubes is very high.

Summary form only. The design of a muon tracking system for the central region of the SDC detector is discussed. The basic tracking elements are aluminum drift tubes with circular cross section with simple field shaping electrodes. The maximum length of the tubes is 9 m and they are operated in proportional mode using a nonflammable gas mixture. These drift tubes are bonded together into modules using structural epoxy. Tubes are properly oriented and precision located during the module assembly by mechanical constraints which are built into the tube endcaps. CNC (computer numerical control) machined reference end plates ensure the relative alignment of anode wires within a module. The largest module is envisaged to be approximately 9 m×8 m and to contain a mixture of θ, φ, and stereo views. Finite element analysis shows that a three-point kinematic support can be used. Full length prototype detectors have been built and studied. Cosmic ray and beam tests have been performed

We report results of the first measurements of Λ and ¯ Λ polarization produced in deep inelastic polarized muon scattering on the nucleon. The results are consistent with an expected trend towards positive polarization with increasing x F. The polarizations of Λ and ¯ Λ appear to have opposite signs. A large negative polarization for Λ at low positive x F is observed and is not explained by existing models. A possible interpretation is presented.

We have built a full scale prototype of the precision tracking chambers (Monitored Drift Tubes, MDT) for the muon spectrometer of the Atlas Experiment at the LHC collider. This article describes in detail the procedures used in constructing the drift tubes and in assembling the chamber. It presents data showing that the required mechanical precision has been achieved as well as test beam results displaying the over all chamber performance. The article presents data demonstrating the derivation of the space-time relation of the drift tubes by the autocalibration procedure using real data from the tracks crossing the chamber. Autocalibration is the procedure which must be used during run time.

We present a full-scale MDT prototype for the Atlas Muon Spectrometer. The chamber consists of two multilayers made of three layers of 96 drift tubes each. The main feature of this chamber is the very accurate mechanical construction (20μm accuracy on single wire positioning) together with a very good individual tube spatial resolution. In this paper we present results both on the mechanical accuracy of the chamber, and on the performances obtained on the H8 test beam at CERN. In particular, we present an autocalibration method that allows to obtain the space-to-time relation of the tubes with a systematic error less than 20μm, the space resolution and the efficiency of the chamber.

The diffractive production of ρ0(770 @#@) mesons in muon-proton interactions is studied in the kinematic region 0.15 GeV2 < Q2 < 20 GeV2 and 20 GeV < ? < 420 GeV. The data were obtained in the Fermilab fixed-target experiment E665 with primary muons of 470 GeV energy. Results are presented on the Q2, x and ? dependence of the cross section, on the shape of the ρ+ρt - mass spectrum, on the slope of the diffraction peak and on the production and decay angular distributions of the ρ0(770). The cross section for diffractive production of ρ0 by virtual photons on protons depends mainly on Q2. At fixed Q2, no significant dependence on x or ? is observed. The extrapolation to Q2 = 0 yields a photoproduction cross section of (10.30 ± 0.33) μb. The slope of the t′ distribution has a value of (7.0 ± 0.2) GeV−2, with a tendency to decrease as Q2 increases. The production and decay angular distributions of the ρ0 depend strongly on Q2 and are consistent with s-channel helicity conservation. The ratio R = σ l /σ t deduced from the decay angular distributions rises strongly with Q2, passing the value of 1 at Q2 ≈ 2 GeV2.

The proton and deuteron structure functions F{sub 2}{sup p} and F{sub 2}{sup d} measured in inelastic muon scattering with an average beam energy of 470 GeV. The data were taken at Fermilab experiment 665 during 1991-1992 using liquid hydrogen and deuterium targets. The F{sub 2} measurements are reported in the range 0.0008 < x < 0.6 and 0.2 < Q{sup 2} < 75 GeV{sup 2}. These are the first precise measurements of F{sub 2} in the low x and Q{sub 2} range of the data. The E665 data overlap in x with the HERA data, and there is a smooth connection in Q{sup 2} between the two data sets. At high Q{sup 2} the E665 measurements are consistent with QCD-evolved leading twist structure function models. The data are qualitatively described by structure function models incorporating the hadronic nature of the photon at low Q{sup 2}. The Q{sup 2} and the W dependence of the data measure the transition in the nature of the photon between a point-probe at high Q{sup 2} and a hadronic object at low Q{sup 2}.

We have used the energy-energy angular pattern of hadrons in inelastic muon-deuteron scattering to study perturbative QCD effects and to extract the gluon distribution functionηG(η) of the nucleon, whereη is the fractional momentum carried by the gluon. The data were taken with the E665 spectrometer using the Fermilab Tevatron muon beam with a mean beam energy of 490 GeV. We presentηG(η) for 0.005<η<0.05 and at an averageQ 2 of 8 GeV2 using this new technique. We find thatηG(η) in this region can be described byηG(η)α ηλ withλ=−0.87±0.09(stat.)± 0.37 0.32 (sys.). We compare our results to expectations from various parametrizations of the parton distribution function and also to results from HERA.

The production of charged hadrons is studied in μXe and μD interactions at 490 GeV beam energy. The data were taken at the Tevatron at Fermilab with the E665 spectrometer, equipped with a streamer chamber as vertex detector. Differences between the μXe and μD data are explained by cascading of hadrons in the Xe nucleus. The average multiplicity of charged hadrons in μXe scattering is compared to previously published pXe scattering data and is found to be strongly reduced. This is traced back to the low number of ‘projectile’ collisions in μXe interactions. From a study of thex Bj dependence of hadron production in μXe scattering, and by considering events with a large rapidity gap, evidence is found for a significant contribution of diffractive scattering, which is enhanced in the kinematic region where shadowing of the cross section is observed. This result supports recent models in which diffractive scattering and nuclear shadowing are closely related.

The ratio of the deuteron to proton structure functions is measured at very small Bjorken $x$ (down to 1${0}^{--6}$) and for ${Q}^{2}>0.001$ Ge${\mathrm{V}}^{2}$ from scattering of 470 GeV muons on liquid hydrogen and deuterium targets. The ratio ${F}_{2}^{n}{/F}_{2}^{p}$ extracted from these measurements is found to be constant, at a value of $0.935\ifmmode\pm\else\textpm\fi{}0.008\ifmmode\pm\else\textpm\fi{}0.034$, for $x<0.01$. This result suggests the presence of nuclear shadowing effects in the deuteron. The dependence of the ratio on ${Q}^{2}$ is also examined; no significant variation is found.

Nuclear shadowing is observed in the per-nucleon cross sections of positive muons on carbon, calcium and lead as compared to deuterium. The data were taken by Fermilab experiment E665 using inelastically scattered muons of mean incident momentum 470 GeV/c. Cross-section ratios are presented in the kinematic region 0.0001<x Bj <0.56 and 0.1<Q2<80 GeV2. The data are consistent with no significant ν orQ2 dependence at fixedx Bj . Asx Bj decreases, the size of the shadowing effect, as well as itsA dependence, are found to approach the corresponding measurements in photoproduction.

Results on the production of charged hadrons in muon-deuteron and muon-xenon interactions are presented. The data were taken with the E665 spectrometer, which was exposed to the 490 GeV muon beam of the Tevatron at Fermilab. The use of a streamer chamber as vertex detector provides nearly 4π acceptance for charged particles. The μD data are compared with the μXe data in terms of multiplicity distributions, average multiplicities, forward-backward multiplicity correlations, rapidity and transverse momentum distributions and of two-particle rapidity correlations of charged hadrons. The data cover a range of invariant hadronic massesW from 8 to 30 GeV.

Results on density integrals Fq(Q2) and correlation integrals Kq(Q2) are presented for the first time in muon-nucleon scattering at ∼ 490 GeV, using data from the E665 experiment at the Tevatron of Fermilab. A clear rise of the Fq integrals with decreasing size of the phase-space cells (“intermittency”) is observed for pairs and triplets of negative hadrons whereas the effect is much weaker for mixed charge combinations. From these findings it is concluded that the observed intermittency signal is mainly caused by Bose-Einstein interference. Furthermore, no energy (W) dependence of F2(Q2) is observed within the W range of the E665 experiment. Finally, the third-order correlation integrals K3(Q2) are found to be significantly different from zero which implies the presence of genuine three-particle correlations in muon-nucleon interactions.