The cross-section ratio of neutral-current and charged-current semileptonic interactions of muon-neutrinos on isoscalar nuclei has been measured with the result:Rv=0.3093±0.0031 for hadronic energy larger than 4 GeV. From this ratio we determined the electroweak mixing angle sin2θW, wheremc is the charm-quark mass in GeV/c2. Comparison with direct measurements ofmw andmz determines the radiative shift of the intermediate boson mass Δr=0.077±0.025(exp.)±0.038(syst.), in agreement with the prediction. Assuming the validity of the electroweak standard theory we determined ϱ=0.990−0.013(mc−1.5)±0.009(exp.)±0.003(theor.).
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STATISTICAL ERROR IN THE VALUE CITED IS REDUCING, WHEN CUT IS MORE STRINGENT?.
We present a measurement of the muon neutrino-nucleon inclusive charged current cross-section, off an isoscalar target, in the neutrino energy range $2.5 \leq E_\nu \leq 40$ GeV. The significance of this measurement is its precision, $\pm 4$% in $2.5 \leq E_\nu \leq 10$ GeV, and $\pm 2.6$% in $10 \leq E_\nu \leq 40$ GeV regions, where significant uncertainties in previous experiments still exist, and its importance to the current and proposed long baseline neutrino oscillation experiments.
Inclusive muon-neutrino charged current cross section.
We present a next-to-leading order QCD analysis of the presently available data on the spin structure function g1 including the final data from the Spin Muon Collaboration. We present results for the first moments of the proton, deuteron, and neutron structure functions, and determine singlet and nonsinglet parton distributions in two factorization schemes. We also test the Bjorken sum rule and find agreement with the theoretical prediction at the level of 10%.
The second systematic (DSYS) error is due to QCD evolution.
First moments of the fitted function G1 evaluated on unmeasured X regions. Total uncertainties due to experimental systematics and theoretical sourc es in the QCD evolution.
First moment of fitted G1 evaluated on the whole X region.
A study of strange particle production in muon neutrino charged current interactions has been performed using the data from the NOMAD experiment. Yields of neutral strange particles K0s, Lambda, AntiLambda have been measured. Mean multiplicities are reported as a function of the event kinematic variables Enu, 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 Lambda in the final state have been analyzed. Clear signals corresponding to K*+-, Sigma*+-, Xi- and Sigma0 have been observed.
Measured yields of the neutral strange particles measured in this analysis.The second line (marked *) is a recalculation taking into account contributions from both primary and secondary V0. The values for K0 are the K0S rates multipl ied by 2.
Measured yields as a function of E, the neutrino energy.
Measured yields as a function of W**2.
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We have studied transverse momenta of charged hadrons in the current fragmentation region of charged current antineutrino- nucleon interactions observed in the Fermilab 15 ft bubble chamber. The measured momentum squared transverse to the v μ + plane (p out 2 ) of the negative hadrons varies as a function of Q 2 , W 2 and x as expected from t he leading order perturbative QCD calculations. Positively charged hadrons show a different transverse momentum behaviour as a function of Q 2 .
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The azimuthal dependence of the flow of hadronic energy about the momentum-transfer direction in charged-current deep-inelastic neutrino-nucleon scattering is used to study gluon emission and the transverse momentum 〈kT〉 of partons confined inside the nucleon. A 7-standard-deviation azimuthal asymmetry is observed indicating an average 〈kT〉=0.303±0.041 GeV/c.
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The results of a study of strange particle production in charged current $\bar{\nu}_{\mu} N$ interactions in the Fermilab 15 ft bubble chamber filled with a heavy $Ne-H_2$ mixture are presented. Production rates and average multiplicities of $K^0$'s and Λ's as functions of W 2 and Q 2 are given. The experimental data agree well with the quark-parton model predictions if a yield of 0.06 ± 0.02 of $K^0$'s and Λ's from charm production is included. Upper limits for D-meson production are given and the shape of the charmed quark fragmentation function is discussed. Inclusive production of the K ∗ (890) and Σ(1385) resonances is measured and it is shown that only about 5% of the K 0 mesons and Λ hyperons results from resonance decays. Relative production rates of neutral strange particles on proton and neutron targets are studied.
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Data on multiplicities of charged particles produced in proton-nucleus and nucleus-nucleus collisions at 200 GeV per nucleon are presented. It is shown that the mean multiplicity of negative particles is proportional to the mean number of nucleons participating in the collision both for nucleus-nucleus and proton-nucleus collisions. The apparent consistency of pion multiplicity data with the assumption of an incoherent superposition of nucleon-nucleon collisions is critically discussed.
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Evidence is presented for diffractive production of ρ-mesons and of ρπ-systems invp and\(\bar \nu p\) chargedcurrent interactions. In the (anti-)neutrino energy range 10 GeV<Ev<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 diffractivea1 production. However, the data cannot distinguish between diffractivea1 and diffractive nonresonant ρπ production. The experimental distributions ofW, Q2,xBj andyBj for diffractive ρ and ρπ events are consistent with model predictions.
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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 squaredQ2. An Extended Vector Meson Dominance Model (EVDM) is applied to extrapolate Adler's prediction to experimentally accessible values ofQ2. The data show good agreement with Adler's prediction forQ2→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 higherQ2, where the EVDM terms are dominant, also supports this model. However, an EVDM calculation without PCAC is clearly ruled out by the data.
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The fragmentation of the hadronic system into Λ, Σ(1385), K ) and K ∗ (892) in deep-inelastic charged-current interactions of high energy neutrinos and antineutrinos with proton and neutron is analyzed. The results obtained for the production of these particles from the various initial states are compared with each other and with the predictions of the Lund fragmentation model. This comparison shows that a spectator diquark does not fragment as a whole in a fraction of the interactions. The role of the sea quarks in the baryon formation process is underlined. Strange vector and pseudoscalar mesons are likely to be produced at similar rates.
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SIG(C=LAMBDA) denotes the inclusive LAMBDA production in the same reaction.
SIG(C=KS) denotes the inclusive KS production in the same reaction.
A significant rate of forward proton and antiproton production has been observed in 120 and 280 GeV muon-proton scattering. The z and p T 2 distributions are presented. The dependence of the normalized production cross section on the muon variables x and Q 2 is studied.
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We present results on the experimental study of inelastic charged-current antineutrino-nucleon scattering in the energy range of 10–200 GeV. The data sample, consisting of about 6500 antineutrino-induced events, was obtained in the Fermilab 15 ft bubble chamber filled with a heavy neon-hydrogen mixture. The differential cross sections for ν μ N interactions are presented in terms of scaling variables x and y . The structure functions F 2 ν and xF 3 ν have been evaluated as functions of x and E ν . A deviation from the scaling hypothesis, similar to those found in other experiments on inelastic lepton-nucleon scattering, has been observed. The data are interpreted in the framework of the quark-parton model. Quark and antiquark distributions and their energy dependences are presented.
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Using data from the Fermilab 15 ft hydrogen bubble chamber, we have studied inclusive ϱ 0 production in antineutrino-proton charged-current interactions. We measure (0.21 ± 0.03) ϱ 0 /event, corresponding to ϱ 0 / π − =0.12 ± 0.02. As a function of Q 2 and for hadronic masses above a threshold region, the ϱ 0 / π − ratio shows little variation. At least 50% of the ϱ 0 's are consistent with coming from the current fragmentation region. The results agree reasonably well with the predictions of the quark fragmentation model of Feynman and field.
AVERAGE BEAM ENERGY 31 GEV.
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The ALICE Collaboration has measured inclusive J/psi production in pp collisions at a center of mass energy sqrt(s)=2.76 TeV at the LHC. The results presented in this Letter refer to the rapidity ranges |y|<0.9 and 2.5<y<4 and have been obtained by measuring the electron and muon pair decay channels, respectively. The integrated luminosities for the two channels are L^e_int=1.1 nb^-1 and L^mu_int=19.9 nb^-1, and the corresponding signal statistics are N_J/psi^e+e-=59 +/- 14 and N_J/psi^mu+mu-=1364 +/- 53. We present dsigma_J/psi/dy for the two rapidity regions under study and, for the forward-y range, d^2sigma_J/psi/dydp_t in the transverse momentum domain 0<p_t<8 GeV/c. The results are compared with previously published results at sqrt(s)=7 TeV and with theoretical calculations.
Double differential J/$\psi$ production cross section at $\sqrt{s}=2.76$ TeV. The first uncertainty is statistical, the second one is $p_{\rm T}$-coorelated, the third one is uncorrelated. Polarization-related uncertainties are not included.
The $\sqrt{s}$-dependence of $\langle p_{\rm T}\rangle$ for inclusive J/$\psi$ production (forward rapidity).
the $\sqrt{s}$-dependence of $\langle p_{\rm T}\rangle$ for inclusive J/$\psi$ production (forward rapidity).
An analysis has been performed of neutrino and antineutrino interactions with protons and neutrons in a deuterium bubble chamber. The interactions under study are quasielastic neutrino-neutron scattering and one-, two- and three-pion production reactions. Results are presented on cross sections, effective mass distributions, resonance production, momentum transfer distributions and coefficients of the decay angular distributions. Where possible, comparisons are made with existing theoretical models and predictions.
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Numerical values supplied by A.Tenner.
Numerical values supplied by A.Tenner.
We have used the momentum spectrum of leptons produced in semileptonic B-meson decays to set a 90%-confidence-level upper limit on Γ(b→ulν)Γ(b→clν) of 4%. We also measure the semileptonic branching fractions of the B meson to be (12.0±0.7±0.5)% for electrons and (10.8±0.6±1.0)% for muons.
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We present the results of a study of the inclusive reaction ν¯p→μ+X0 for antineutrino energies from 5 to 150 GeV. The data were obtained by exposing the Fermi National Accelerator Laboratory hydrogen-filled 15-foot bubble chamber to a wide-band antineutrino beam. This is the first high-energy antineutrino experiment in which a pure proton target was used. The experimental problems of selecting the required sample of charged-current antineutrino-induced events are discussed in detail. A Monte Carlo simulation of the experiment is used to provide correction factors to the measured distributions. A measurement of the x dependence of the inelasticity (y) distributions gives the proton structure functions F2ν¯p(x) and xF3ν¯p(x) up to an overall normalization constant. When expressed in terms of the quark-parton model, the quark distributions u(x) and d¯(x)+s¯(x) are determined. The results for u(x) are found to be in excellent agreement with models based on fits to electron and muon scattering data. Using these results to fix the u(x) normalization, an absolute measurement is made of x[d¯(x)+s¯(x)], the antiquark momentum distribution.
VALUES OF Q**2 ASSOCIATED WITH THE FOLLOWING TABLE ARE.... 2.2 , 3.5 , 3.4 , 4.4 , 4.7 , 5.0 , 6.0 , 6.5 , 7.7 , 8.0.
After completion of the data taking for the νμ→ντ oscillation search, the CHORUS lead–scintillator calorimeter was used in the 1998 run as an active target. High-statistics samples of charged-current interactions were collected in the CERN SPS west area neutrino beam. This beam contained predominantly muon (anti-)neutrinos from sign-selected pions and kaons. We measure the flux and energy spectrum of the incident neutrinos and compare them with beam simulations. The neutrino–nucleon and anti-neutrino–nucleon differential cross-sections are measured in the range 0.01<x<0.7 , 0.05<y<0.95 , 10<Eν<200 GeV . We extract the neutrino–nucleon structure functions F2(x,Q2) , xF3(x,Q2) , and R(x,Q2) and compare these with results from other experiments.
The measured F2 and xF3 at X = 0.020.
The measured F2 and xF3 at X = 0.045.
The measured F2 and xF3 at X = 0.080.
We present a measurement of the polarization of Antilambda hyperons produced in nu_mu 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 for the case of Lambda hyperons. The Antilambda polarization has been measured for the first time in a neutrino experiment. The polarization vector is found to be compatible with zero.
Lambdabar polarization in regions of Feynman X (XL).
Lambdabar polarization in regions of the Bjorken scaling variable X.
The Fermilab wide-band antineutrino beam incident on the hydrogen-filled 15-foot bubble chamber was used to study ν¯p neutral-current interactions. The u=x(1−y) distribution is presented for both the neutral- and the charged-current data sample. Fitting the neutral-current u distribution to the prediction of a simple quark-parton model measures the Weinberg angle. By using recent measurements of the neutral-to-charged-current cross-section ratio for νp interactions (Rp), we find the corresponding ratio for ν¯p interactions (R¯p) to be 0.36±0.06.
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The isoscalar structure functions xF_3 and F_2 are measured as functions of x averaged over all Q~2 permissible for the range 6 to 28 GeV of incident (anti)neutrino energy. With the measured values of xF_3, the value of the Gross-Llewellyn Smith sum rule is found to be $\int_{0}~{1}{F_3 dx} = 2.13\pm0.38 (stat)\pm 0.26 (syst)$. The QCD analysis of xF_3 provides $\Lambda_{\overline{MS}} =358 \pm 59 MeV$ . The obtained value of the strong interaction constant $\alpha_S (M_Z)=0.120~{+3}_{-4}$ is larger than most of the deep inelastic scattering results.
The value of F2 is extracted with R = 0. The difference F2(C=R=.1)-F2(C=R=0.) is also presented.
The isoscalar structure functions $xF_3$ and $F_2$ are measured as functions of $x$ averaged over all $Q^2$ permissible for the range of 6 to 28 GeV of incident neutrino (anti-neutrino) energy at the IHEP-JINR Neutrino Detector. The QCD analysis of $xF_3$ structure function provides $\Lambda_{\bar{MS}}^{(4)} = (411 \pm 200)$ MeV under the assumption of QCD validity in the region of low $Q^2$. The corresponding value of the strong interaction constant $\alpha_S (M_Z) = 0.123^{+0.010}_{-0.013}$ agrees with the recent result of the CCFR collaboration and with the combined LEP/SLC result.
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Data on the measurement of the v μ N total cross section at 2–30 GeV are presented. The observed behavior does not contradict a linear dependence on neutrino energy with slope S =0.73 ± 0.08.
Measured charged current total cross section.
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Axis error includes +- 0.0/0.0 contribution (?////NOT GIVEN).
Axis error includes +- 0.0/0.0 contribution (?////NOT GIVEN).
Axis error includes +- 0.0/0.0 contribution (?////NOT GIVEN).
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The first observation of μ + e + events produced in antineutrino interactions using the Fermilab 15 ft bubble chamber is reported. The relative yield of μ + e + events is (4.8 −3.2 +5.3 ) × 10 −4 of all charged-current events with antineutrino energy greater than 10 GeV. The observed V 0 rate is 1.0 −1.0 +1.2 per μ + e + event. Possible sources of these events are discussed.
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Axis error includes +- 10/10 contribution.
Axis error includes +- 10/10 contribution.
Axis error includes +- 10/10 contribution.
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Statistical errors only.
We present results on inclusive particle production in the antineutrino charged current induced hadron jets observed in the Fermilab 15 ft bubble chamber. Fractional energy distributions, particle ratios and average multiplicities of the hadrons in the jets are measured. Ratios between the inclusive production rates of different mesons in the jets are studied to seek evidence for the d-quark origin of the observed hadrons. Good over-all agreement with the hypothesis of d-quark fragmentation with universal fragmentation functions obeying isospin systematics is established.
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In the 1992–1995 runs CDF has collected large samples of J ψ , ψ (2 S ) and ϒ identified through their muonic decay. In the charmonium system all production sources have been separately measured and compared with the theoretical predictions. A large excess of direct production has been observed for both ψ (2 S ) and J ψ . The relative production rate for the χ c 1 and χ c 2 has also been measured. The unexpected results have lead to a profound revisitation of the theory of the production of Q Q bound states in high energy hadronic collisions.
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Experimental results on the study of quasielastic reactionsvμn→μ−p and\(\bar v_u p \to \mu ^ +n\) in the energy range 3–30 GeV are presented in this paper. Spark chamber detector with Al filters has been exposed to the wide-band neutrino and antineutrino beams at Serpukhov. Neutrino and antineutrino data have been used to reconstruct the behaviour of axial-vector form-factorFA(Q2). We measured the total cross-sections as a function of energy. The parameterMA=(1.00±0.04) GeV/c2 has been determined under the assumption of the dipole parametrization and CVC hypothesis. Upper limit for the second class currents was estimated.
Statistical errors only.
Statistical errors only.
The cross sections of neutrino and antineutrino quasielastic reactions\(vn \to \mu ^ -p,\bar vp \to \mu ^ +n,\bar vp \to \mu ^ +\Lambda\) were studied in the neutrino energy range between 3 and 30 GeV. In comparison withV-A theory axial mass parameters ofMA=(1.06±0.05±0.14) GeV/c2 from neutrino andMA=(0.71±0.10±0.20) GeV/c2 from antineutrino data were found. The total cross-section for the hyperon production process can be described byMA=1.0 GeV/c2.
Measured Quasi-Elastic total cross section.
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Axis error includes +- 0.0/0.0 contribution (?////DUE TO UNCERTAINTY IN NU SPECTRUM).
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SIG(Q=L)/SIG(Q=T) ASSUMED TO BE 0.
SIG(Q=L)/SIG(Q=T) ASSUMED TO BE 0.
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We have searched for second generation leptoquark (LQ) pairs in the \mu\mu+jets channel using 94+-5 pb^{-1} of pbar-p collider data collected by the D0 experiment at the Fermilab Tevatron during 1993-1996. No evidence for a signal is observed. These results are combined with those from the \mu\nu+jets and \nu\nu+jets channels to obtain 95% confidence level (C.L.) upper limits on the LQ pair production cross section as a function of mass and $beta, the branching fraction of a LQ decay into a charged lepton and a quark. Lower limits of 200(180) GeV/c^2 for \beta=1(1/2) are set at the 95% C.L. on the mass of scalar LQ. Mass limits are also set on vector leptoquarks as a function of \beta.
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We report on a search for second generation leptoquarks (Phi_2) using a data sample corresponding to an integrated luminosity of 110 pb^{-1} collected at the Collider Detector at Fermilab. We present upper limits on the production cross section as a function of Phi_2 mass, assuming that the leptoquarks are produced in pairs and decay into a muon and a quark with branching ratio beta. Using a Next-to-Leading order QCD calculation, we extract a lower mass limit of M_{\Phi_2} > 202 (160) GeV$/c^{2} at 95% confidence level for scalar leptoquarks with beta=1(0.5).
Cross section times branching ratios.
Forum