Search

This paper describes an analysis of the angular distribution of W → e? and W → μ? decays, using data from pp collisions at √s = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb-1. Using the decay lepton transverse momentum and the missing transverse momentum, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (pW/T ) : 35 50 GeV. Good agreement is found with theoretical predictions. For pW/ T > 50 GeV, the values of f0 and fL - fR, averaged over charge and lepton flavour, are measured to be: f0 = 0.127±0.030±0.108 and fL-fR = 0.252±0.017±0.030, where the first uncertainties are statistical, and the second include all systematic effects. [ABSTRACT FROM AUTHOR]

A search for pair-produced scalar particles decaying to a four-jet final state is presented. The analysis is performed using an integrated luminosity of 34 pb−1 recorded by the ATLAS detector in 2010. No deviation from the Standard Model is observed. For a scalar mass of 100 GeV (190 GeV) the limit on the scalar gluon pair production cross section at 95% confidence level is 1 nb (0.28 nb). When these results are interpreted as mass limits, scalar-gluons (hyperpions) with masses of 100 to 185 GeV (100 to 155 GeV) are excluded at 95% confidence level with the exception of a mass window of width about 5 GeV (15 GeV) around 140 GeV. [ABSTRACT FROM AUTHOR]

A search is presented for a high mass neutral particle that decays directly to the e±μ∓ final state. The data sample was recorded by the ATLAS detector in pp collisions at the LHC from March to June 2011 and corresponds to an integrated luminosity of 1.07 fb−1. The data are found to be consistent with the Standard Model background. The high e±μ∓ mass region is used to set 95% confidence level upper limits on the production of two possible new physics processes: tau sneutrinos in an R-parity violating supersymmetric model and Z′-like vector bosons in a lepton flavor violating model. [ABSTRACT FROM AUTHOR]

The jet fragmentation function and transverse profile for jets with 25 GeVT jet<500 GeV and |ηjet|<1.2 produced in proton–proton collisions with a center-of-mass energy of 7 TeV are presented. The measurement is performed using data with an integrated luminosity of 36 pb−1. Jets are reconstructed and their momentum measured using calorimetric information. The momenta of the charged particle constituents are measured using the tracking system. The distributions corrected for detector effects are compared with various Monte Carlo event generators and generator tunes. Several of these choices show good agreement with the measured fragmentation function. None of these choices reproduce both the transverse profile and fragmentation function over the full kinematic range of the measurement. [ABSTRACT FROM AUTHOR]

Measurements of luminosity obtained using the ATLAS detector during early running of the Large Hadron Collider (LHC) at TeV are presented. The luminosity is independently determined using several detectors and multiple algorithms, each having different acceptances, systematic uncertainties and sensitivity to background. The ratios of the luminosities obtained from these methods are monitored as a function of time and of μ, the average number of inelastic interactions per bunch crossing. Residual time- and μ-dependence between the methods is less than 2% for 0<μ<2.5. Absolute luminosity calibrations, performed using beam separation scans, have a common systematic uncertainty of ±11%, dominated by the measurement of the LHC beam currents. After calibration, the luminosities obtained from the different methods differ by at most ±2%. The visible cross sections measured using the beam scans are compared to predictions obtained with the PYTHIA and PHOJET event generators and the ATLAS detector simulation. [ABSTRACT FROM AUTHOR]

A method is developed for separating vN interactions from interactions involving an intranuclear cascade in vNe scattering at a mean neutrino energy of 145 GeV. The fraction of events featuring a cascade is evaluated by using a sample of vNe charged-current interactions. It is found that the multiplicity of charged particles in the forward direction takes the same value for events with and without a cascade for 4 < W² < 550 GeV². In the backward direction, cascade events have the charge multiplicity higher than the multiplicity for cascade-free events by 2.36 units. It is found that particles with momenta less than 2 GeV/c make a dominant contribution to the rescattering process. A depletion of the fastest particles for W² < 50 GeV² is observed, in accord with the formation-time concept. [ABSTRACT FROM AUTHOR]

The production of hadrons in charged-current (anti)neutrino interactions is studied with the bubble chamber BEBC exposed to the CERN (anti)neutrino wide-band beam. Fast-hadron production in a neon target is found to be attenuated as compared to that in a hydrogen target. This feature is discussed within theoretical models based on the idea of a hadron formation length. The experimental results favour the 'constituent' over the 'yo-yo' length concept, and suggest a quark cross section in the order of 3 mb. [ABSTRACT FROM AUTHOR]

Data from BEBC experiments are combined to provide large statistics for neutrino interactions. Charged D mesons are produced in (1.22±0.25)% of neutrino and (1.01±0.31)% of antineutrino charged current interactions. The mean fraction of the hadronic laboratory energy taken by the D in these events is 0.59±0.03±0.08. Less than 18% of all charged D mesons from (anti)neutrino interactions are found to be daughters of D (at the 90% confidence level). [ABSTRACT FROM AUTHOR]

Most of the measured events on hydrogen, deuterium and neon targets from BEBC at CERN and the 15-foot Bubble Chamber at Fermilab are combined to measure spin-density matrix elements for ρ production in the current-fragmentation region in neutrino and antineutrino charged-current interactions. The spin-alignment parameter η is found to be 0.08±0.11 for neutrino and 0.41±0.11 for antineutrino interactions. The parity-odd density matrix element Im(ρ+ρ) is consistent with zero in both reactions. In the combined neutrino and antineutrino data an indication of parity violation is observed: Im ρ=0.38±0.16 at x>0.2, Q>8 GeV and z>0.6. [ABSTRACT FROM AUTHOR]

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 the x 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. [ABSTRACT FROM AUTHOR]

This analysis is based on data from neutrino and antineutrino scattering on hydrogen and deuterium, obtained with BEBC in the (anti) neutrino wideband beam of the CERN SPS. The parton momentum distributions in the proton and the proton structure functions are determined in the range 0.01

Based on a QCD analysis of the parton momentum distributions in the proton, the ratio r= d/ u of the d and u valence quark distributions is determined as function of x in the range 0.01< x<0.7. The analysis uses data from neutrino and antineutrino charged current interactions on hydrogen and deuterium, obtained with BEBC in the (anti)neutrino wideband beam of the CERN SPS. Since mainly depends on the deuterium/hydrogen ratios of the normalised x-y-Q-distributions many systematic effects cancel. It is found that r decreases with increasing x, and drops below the naive SU(6) expectation of 0.5 for x≳0.3. An extrapolation of r to x=1 is consistent with the hypothesis r(1)=0. [ABSTRACT FROM AUTHOR]

The production of K, Λ and $$\bar \Lambda $$ particles is studied in the E665 muon-nucleon experiment at Fermilab. The average multiplicities and squared transverse momenta are measured as a function of x and W. Most features of the data can be well described by the Lund model. Within this model, the data on the K/π ratios and on the average K multiplicity in the forward region favor a strangeness suppression factor s/u in the fragmentation process near 0.20. Clear evidence for QCD effects is seen in the average squared transverse momentum of K and Λ particles. [ABSTRACT FROM AUTHOR]

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 masses W from 8 to 30 GeV. [ABSTRACT FROM AUTHOR]

Four data sets of charged current neutrino and antineutrino interactions with neon, deuterium and hydrogen collected from BEBC and the 15 Foot Bubble Chamber are used to study the Bose-Einstein correlations between like-sign charged pions. Two forms of the parametrization for the effect are used. No substantial differences are found between the data sets obtained with neon, deuterium and hydrogen targets. The Lorentz invariant parametrization of Goldhaber gives for the radius of the pion emission region the value r=0.80 ±0.04±0.16 fm and for the chaoticity parameter the value ψ=0.61±0.04±0.15. Using the Kopylov-Podgoretskii parametrization yields r=1.27±0.06±0.12 fm, ψ=0.58±0.03±0.12 and for the pion source lifetime c=0.52±0.05±0.12 fm. The Goldhaber parametrization was used to study the effect in further detail. The same emission radius and the same strength of the effect were found for particles produced in interactions on neutrons and protons. The data are compatible with a spherical shape of the pion emission region. No multiplicity or forward-backward dependences are found. No dependence of the effect on the event kinematical variables is seen. [ABSTRACT FROM AUTHOR]

Evidence is presented for diffractive production of ρ-mesons and of ρπ-systems in vp and $$\bar \nu p$$ chargedcurrent interactions. In the (anti-)neutrino energy range 10 GeV< E<60 GeV the cross sections for diffractive ρ and diffractive ρπ production are found to be (0.64±0.14 (stat.)±0.08 (syst.))% and (0.28±0.08 (stat.)±0.04 (syst.))% of the charged-current cross section. The diffractive ρπ signal is consistent with being entirely due to diffractive a production. However, the data cannot distinguish between diffractive a and diffractive nonresonant ρπ production. The experimental distributions of W, Q, x and y for diffractive ρ and ρπ events are consistent with model predictions. [ABSTRACT FROM AUTHOR]

The diffractive production of charmed strange D and possibly D mesons by neutrinos and antineutrinos on nucleons in hydrogen, deuterium and neon targets is observed. The slope parameter of the t distribution is 3.3±0.8 (GeV). The production rate per charged current neutrino interaction with an isoscalar target times the D→φτ branching fraction is (1.03±0.27)×10. [ABSTRACT FROM AUTHOR]

The production of the neutral strange particles K, Λ and $$\bar \Lambda $$ in vp and $$\bar vp$$ charged current interactions is studied in an experiment with the Big European Bubble Chamber. Mean multiplicities are measured as a function of the event variables E, W and Q and of the hadron variables x, z and p. K (892) and ∑ (1385) signals are observed, whereas there is no evidence for ∑ (1385) production in vp scattering. Forward, backward and total mean multiplicities are found to compare well with the predictions of an empirical model for deep-inelastic reactions in the case of the strange mesons K and K (892) but less so for the strange baryons Λ, $$\bar \Lambda $$ and ∑ (1385). The strange baryon multiplicities are used to obtain the decuplet to octet baryon production ratio and to assess the probabilities of a uu or ud system to break up. [ABSTRACT FROM AUTHOR]

Using data on vp and $$\bar vp$$ charged current interactions from a bubble chamber experiment with BEBC at CERN, the multiplicity distributions of charged hadrons are investigated. The analysis is based on ∼20000 events with incident v and ∼10000 events with incident $$\bar v$$ . The invariant mass W of the total hadronic system ranges from 3 GeV to ∼14 GeV. The experimental multiplicity distributions are fitted by the binomial function (for different intervals of W and in different intervals of the rapidity y), by the Levy function and the lognormal function. All three parametrizations give acceptable values for X. For fixed W, forward and backward multiplicities are found to be uncorrelated. The normalized moments of the charged multiplicity distributions are measured as a function of W. They show a violation of KNO scaling. [ABSTRACT FROM AUTHOR]

Neutral strange particle production in $$\bar v$$ Ne charged current interactions is studied using the bubble chamber BEBC, exposed to the CERN SPS antineutrino wide band beam. From a sample of 1191 neutral strange particles, the inclusive production rates are determined to be (15.7±0.8)% for K mesons, (8.2±0.5)% for Λ, (0.4±0.2)% for $$\bar \Lambda $$ and (0.6±0.3)% for Σ hyperons. The inclusive production properties of K mesons and Λ hyperons are investigated. The Λ hyperons are found to be polarized in the production plane. [ABSTRACT FROM AUTHOR]

Using data obtained with the bubble chamber BEBC at CERN, the inclusive f (1270) meson production in vp and $$\bar vp$$ charged current reactions is studied. It is found that f production occurs mainly in events with a hadronic invariant mass W≳7 GeV. In these events, the average f multiplicity is about half the average ρ multiplicity, and the x and p distributions of the f agree in shape with those of the ρ. The predictions of a semi-empirical model (Wells model) are in accord with the measured multiplicities at W>7 GeV, whereas at lower W the model predicts too large f multiplicities. [ABSTRACT FROM AUTHOR]

Using data obtained with the bubble chamber BEBC at CERN, the inclusive ρ (770) meson production in ν p and $$\bar vp$$ charged current reactions is studied. The average ρ multiplicity is measured as a function of the event variables E, W, Q, x, and the charged multiplicity. The differential x, y, z and p distributions of the ρ are presented as well as the average p as a function of W and x. The ρ/π ratio and the fractions of the π originating from ρ decays are given as functions of x. The results are compared to the predictions of fragmentation models. A particular version of the Lund model predicts ρ multiplicities which are generally too high, although it qualitatively reproduces many aspects of the data. The ρ multiplicities predicted by a semi-empirical model (Wells model) are in quantitative agreement with the measurements. [ABSTRACT FROM AUTHOR]

The coherent production of 3π systems by charged current antineutrino interactions on neon nuclei is studied in the bubble chamber BEBC exposed to the CERN SPS wide band beam. The coherent signal is attributed mainly to (ρπ) production, where the (ρπ) system is either non-resonant or comes from the decay of a mesons. The kinematical variables and the total cross section are compared with the predictions of the meson dominance model. [ABSTRACT FROM AUTHOR]

Using data on vp and $$\bar vp$$ charged current interactions from a bubble chamber experiment with BEBC at CERN, the average multiplicities of charged hadrons and pions are determined as functions of W and Q . The analysis is based on ∼20000 events with incident v and ∼10000 events with incident $$\bar v$$ . In addition to the known dependence of the average multiplicity on W a weak dependence on Q for fixed intervals of W is observed. For W>2 GeV and Q >0.1 GeV the average multiplicity of charged hadrons is well described by 〈n〉=a + a ln( W /GeV)+ a ln( Q /GeV) with a =0.465±0.053, a =1.211±0.021, a =0.103±0.014 for the vp and a =−0.372±0.073, a =1.245±0.028, a =0.093±0.015 for the $$\bar vp$$ reaction. [ABSTRACT FROM AUTHOR]

Within the framework of the quark-parton model, the quark and anti-quark structure functions of the proton have been measured by fitting them to the distributions of the events in the Bjorken y variable. The data used form the largest sample of neutrino and antineutrino interactions on a pure hydrogen target available, and come from exposures of BEBC to the CERN wide band neutrino and antineutrino beams. It is found that the ratio d/ u of valence quark distributions falls with increasing Bjorken x. In the context of the quark-parton model the results constrain the isospin composition of the accompanying diquark system. Models involving scattering from diquarks are in disagreement with the data. [ABSTRACT FROM AUTHOR]

The production of the meson resonances ϱ(770) (all three charge states), η(550), ω(783) and f(1270) in $$\bar v$$ Ne and ν Ne charged current interactions is investigated in a bubble chamber experiment with BEBC at CERN. Except for the f, the main features of resonance production are reasonably well described by the Lund model, although the average resonance multiplicities are overestimated by the model by (67±30)%. The average multiplicities of all resonances, including the f, are well reproduced by a semiempirical model, whose parameters were determined from hadron interaction data. [ABSTRACT FROM AUTHOR]

Data on the reactions v p→ μ pπ and $$ \bar v_\mu p \to \mu ^ + p\pi ^ - $$ in the Δ(1232) region are presented and a test of the PCAC hypothesis, using a modified version of the Adler model, is performed. The analysis is based on 1081 events in the neutrino and on 180 events in the antineutrino reaction, obtained in a bubble chamber experiment with BEBC at CERN. The experimental cross-sections for an invariant hadronic mass W<1.4 GeV and an (anti-)neutrino energy E>10 GeV are determined to be (0.628±0.059)·10 cm for the neutrino and (0.168±0.023)·10 cm for the antineutrino reaction. The Q and W distributions, the density matrix elements of the Δ resonance, and moments of the pion angular distribution are discussed. The data are found to be in good agreement with the Adler model in the Q region below 1 GeV. A maximum likelihood fit for the axial mass m in the axial-vector form factor yields a value of m=1.31±0.12 GeV. At low Q the data confirm the PCAC hypothesis and the discrepancy, formerly observed between the experimental and theoretical cross-sections for v p→ μ pπ at low momentum transfers ( Q≲0.2 GeV), is understood as being due to inadequate pion 'off-mass-shell' corrections. [ABSTRACT FROM AUTHOR]

The average multiplicities of charged hadrons and of π, π and π mesons, produced in $$\bar v$$ Ne and νNe charged current interactions in the forward and backward hemispheres of the W-nucleon center of mass system, are studied with data from BEBC. The dependence of the multiplicities on the hadronic mass ( W) and on the laboratory rapidity ( y) and the energy fraction ( z) of the pion is also investigated. Special care is taken to determine the π multiplicity accurately. The ratio of average π multiplicities $$\frac{{2\left\langle {n_{\pi ^O } } \right\rangle }}{{[\left\langle {n_{\pi ^ + } } \right\rangle + \left\langle {n_{\pi ^ - } } \right\rangle ]}}$$ is consistent with 1. In the backward hemisphere $$\left\langle {n_{\pi ^O } } \right\rangle $$ is positively correlated with the charged multiplicity. This correlation, as well as differences in multiplicities between $$\mathop v\limits^{( - )} $$ and $$\mathop v\limits^{( - )} $$ , $$\mathop v\limits^{( - )} $$ scattering, is attributed to reinteractions inside the neon nucleus of the hadrons produced in the initial $$\mathop v\limits^{( - )} $$ interaction. [ABSTRACT FROM AUTHOR]

Data obtained with the bubble chamber BEBC at CERN are used for the first significant test of Adler's prediction for the neutrino and antineutrino-proton scattering cross sections at vanishing four-momentum transfer squared Q. An Extended Vector Meson Dominance Model (EVDM) is applied to extrapolate Adler's prediction to experimentally accessible values of Q. The data show good agreement with Adler's prediction for Q→0 thus confirming the PCAC hypothesis in the kinematical region of high leptonic energy transfer ν>2 GeV. The good agreement of the data with the theoretical predictions also at higher Q, where the EVDM terms are dominant, also supports this model. However, an EVDM calculation without PCAC is clearly ruled out by the data. [ABSTRACT FROM AUTHOR]

Usind data from a vp and $$\bar v$$ p experiment with BEBC at CERN, the rates for inclusive production of D, Λ and D in vp scattering and of D in $$\bar v$$ p scattering are measured. Some examples of the exclusive production of D, Λ and ∑ are given. The cross section for the reaction vp→ μ is estimated. [ABSTRACT FROM AUTHOR]

The isoscalar nucleon structure functions F( x, Q) and xF( x, Q) are measured in the range 0< Q<64 GeV, 1.7< W<250 GeV, x<0.7 using ν and $$\bar v$$ interactions on neon in BEBC. The data are used to evaluate possible higher twist contributions and to determine their impact on the evaluation of the QCD parameter Λ. In contrast to previous analyses reaching to such low W values, it is found that a low $$\Lambda _{\overline {MS} } $$ value in the neighbourhood of 100 MeV describes the data adequately and that the contribution of dynamical higher twist effects is small and negative. [ABSTRACT FROM AUTHOR]

Coherent production of ρ mesons in charged current antineutrino interactions on neon nuclei is studied in the BEBC bubble chamber exposed to the CERN SPS wide band beam. The cross section is measured to be (95±25)·10 cm per neon nucleus, averaged over the beam energy spectrum. The distributions of kinematical variables and the absolute value of the cross section are in agreement with theoretical predictions based on the CVC hypothesis and the vector meson dominance model. [ABSTRACT FROM AUTHOR]

The cross section for coherent production of a single π meson in charged current antineutrino interactions on neon nuclei has been measured in BEBC to be (175±25) 10 cm/neon nucleus, averaged over the energy spectrum of the antineutrino wide band beam at the CERN SPS; this corresponds to (0.9±0.1) % of the total charged current $$\bar v_\mu $$ cross section. The distributions of kinematical variables are in agreement with theoretical predictions based on the PCAC hypothesis and the meson dominance model; in particular, the Q dependence is well described by a propagator containing a mass m=(1.35±0.18) GeV. The absolute value of the cross section is also in agreement with the model. This analysis thus provides a test of the PCAC hypothesis in the antineutrino energy range 5-150 GeV. [ABSTRACT FROM AUTHOR]

Evidence for a significant higher twist contribution to high z π production in antineutrino scattering is presented. In events with W>3 GeV and Q>1 GeV in our data, it accounts for (51 ±8)% of all π with z above 0.5. It is consistent with the z− Q correlations of Berger's higher twist prediction. The data are inconclusive concerning the predicted y−z correlation and p dependence. The z − Q correlation is not adequately described by the Lund Monte-Carlo. [ABSTRACT FROM AUTHOR]

A sample of over 25,000 fully measured neutrino and antineutrino charged current interactions in BEBC includes 192 dilepton candidates. The prompt signal after subtraction of background is 41 ±7µ e, 35±7µµ events from $$\bar v$$ interactions, and 32±7µµ events from ν interactions. There are 2 trileptons, µµ e and µµµ. Results are compared with other experimental data and with the standard model. Limits to prompt like sign µ e, µµ and µµ signals are given and compared with other experiments and with theoretical calculations. [ABSTRACT FROM AUTHOR]

Lambda hyperons from v p and $$\bar v$$ p charged current interactions have been analysed for polarization. A significant polarization is observed for Λ particles in the quasi-elastic region for both types of interactions. Part of this polarization is due to the decay of highly polarized Σ(1385) resonances. The results are compared with simple predictions of the quark parton model. [ABSTRACT FROM AUTHOR]

Neutral kaon to negative pion production ratios from vp and $$\bar vp$$ charged current interactions in BEBC are presented and compared with LUND fragmentation model predictions. Good agreement is obtained with a strangeness suppression factor λ=0.203±0.014(stat)±0.010(sys). No evidence is seen for an energy dependence of λ in our kinematic region. [ABSTRACT FROM AUTHOR]

Data from a neutrino and antineutrino hydrogen experiment with BEBC are used to investigate transverse properties of the produced charged hadrons. Measurements are presented on average transverse momenta of charged pions as functions of Feynman- x and the hadronic mass, on the transverse momentum flow within an event and on jet-related quantities. The main features of the data are well described by the LUND model. The data favour a version of the model in which soft gluon effects are included and the primordial transverse momentum of the quarks in the proton is small. Effects from 1 order QCD (hard gluon emission) are negligible. [ABSTRACT FROM AUTHOR]

A study is presented of μ e events from an exposure of BEBC, filed with an heavy H/ Ne mixture, to a wide band antineutrino beam at the CERN SPS. The prompt μ e rate, based on the observation of 45 events with p>4 GeV/c and p>0.8 GeV/c, is found to be 0.31±0.05±0.02%, in agreement with previous determinations made on much smaller statistics. The differential kinematical variables characterizing the events and the content of strange particles are as expected for the production of charmed hadrons which subsequently decay semi-leptonically. An upper limit of 2.0±10 at 90% C.L. is given for the production rate of prompt μ e events. No evidence is found for a significant production of Beauty hadrons. [ABSTRACT FROM AUTHOR]

The diffractive production of ρ(770 @#@) mesons in muon-proton interactions is studied in the kinematic region 0.15 GeV < Q < 20 GeV 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 Q, x and ? dependence of the cross section, on the shape of the ρρ mass spectrum, on the slope of the diffraction peak and on the production and decay angular distributions of the ρ(770). The cross section for diffractive production of ρ by virtual photons on protons depends mainly on Q. At fixed Q, no significant dependence on x or ? is observed. The extrapolation to Q = 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, with a tendency to decrease as Q increases. The production and decay angular distributions of the ρ depend strongly on Q and are consistent with s-channel helicity conservation. The ratio R = σ /σ deduced from the decay angular distributions rises strongly with Q, passing the value of 1 at Q ≈ 2 GeV. [ABSTRACT FROM AUTHOR]

A sample holder made of fused silica, suitable for performing precise measurements of the magnetic moment at elevated temperatures (300–700 K) using a superconducting quantum interference device magnetometer, is presented. The sample holder has a simple design, is easily fabricated and capable of multiple usage. Test measurements of the magnetic moment of a granular multilayer sample [Co80Fe20(1.6 nm)/Al2O3(3 nm)]9 are performed and corrected for the background data from the empty sample holder. [ABSTRACT FROM AUTHOR]

Neutrino interactions in BEBC produce the D (2536) charmed strange meson. The mass of this state is 2534.2±1.2 MeV. The production rate is 0.011±0.005 per neutrino charged current interaction at a mean neutrino energy of 61 GeV. An earlier claim for another $$c\bar s$$ bound state near 2565 MeV, produced in neutrino interactions, is not supported. [ABSTRACT FROM AUTHOR]