Measurements have been made of the inclusive scattering of 96, 147, and 219 GeV muons from hydrogen, and of 147 GeV muons from deuterium. Results are presented for the nucleon structure function F2(x,Q2) [≡νW2(x,Q2)] for 10<ν<200 GeV and 0.2<Q2<80 GeV2. The value of F2 rises with Q2 at small x, and falls with Q2 at large x, in agreement with the ideas of quantum chromodynamics. An average value of the ratio σLσT≡R=0.52±0.35 has been obtained for the region 0.003<x<0.10 and 0.4<Q2<30 GeV2. The values of F2 from this experiment have been combined with those from other charged-lepton scattering experiments to determine moments of the structure functions. The variation with Q2 of these moments is used to derive values for Λ, taking into account corrections up to second order in αs. The fit to the data is very good.
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This paper reports measurements of the hadrons produced in the inelastic scattering of 147-GeV muons by protons and deuterons in an experiment carried out at Fermi National Accelerator Laboratory. Both the scattered muon and the hadrons were measured in a large spectrometer. Properties of the hadron spectra are presented for proton, deuteron, and neutron targets and compared with theoretical models and with hadron spectra from related processes. Emphasis is placed on the quark-parton model and the data are found to be in substantial agreement with it. The average transverse momentum of the hadrons with respect to the virtual photon direction shows no dependence on the muon scattering variables. The data display "jet behavior" of the inclusive hadrons comparable to that found in e+e− annihilations.
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We have studied muon-produced hadrons from a deuterium target. The structure functions and the charge ratios are reported for neutrons; the transverse momentum and azimuthal distributions are reported for deuterons. The structure function for the neutron is similar to that of the proton. The charge ratio of produced hadrons follows the expectation of a simple spin-½ quark model. Transverse-momentum results agree with those at lower energy and are similar to those from hadron-hadron interactions. No azimuthal anisotropy is seen.
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Inclusive hadron production in muon-proton inelastic scattering has been measured for q2>0.5 (GeV/c)2 and 10<ν<135 GeV. The results are presented in the form of the transverse momentum distribution of charged hadrons and the hadron invariant structure function F(x′). Results are given for different regions of q2 and s.
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Two different nuclear-medium effects are isolated using a low three-momentum transfer subsample of neutrino-carbon scattering data from the MINERvA neutrino experiment. The observed hadronic energy in charged-current $\nu_\mu$ interactions is combined with muon kinematics to permit separation of the quasielastic and $\Delta$(1232) resonance processes. First, we observe a small cross section at very low energy transfer that matches the expected screening effect of long-range nucleon correlations. Second, additions to the event rate in the kinematic region between the quasielastic and $\Delta$ resonance processes are needed to describe the data. The data in this kinematic region also has an enhanced population of multi-proton final states. Contributions predicted for scattering from a nucleon pair have both properties; the model tested in this analysis is a significant improvement but does not fully describe the data. We present the results as a double-differential cross section to enable further investigation of nuclear models. Improved description of the effects of the nuclear environment are required by current and future neutrino oscillation experiments.
The $\nu_\mu$ flux, in units 10$^{-5}$ / m$^{2}$ / P.O.T. / GeV.
Measured cross section per nucleon, in units 10$^{-42}$ cm$^2$ / GeV$^2$.
Single neutral pion production via muon antineutrino charged-current interactions in plastic scintillator (CH) is studied using the \minerva detector exposed to the NuMI low-energy, wideband antineutrino beam at Fermilab. Measurement of this process constrains models of neutral pion production in nuclei, which is important because the neutral-current analog is a background for $\bar{\nu}_e$ appearance oscillation experiments. The differential cross sections for $\pi^0$ momentum and production angle, for events with a single observed $\pi^0$ and no charged pions, are presented and compared to model predictions. These results comprise the first measurement of the $\pi^0$ kinematics for this process.
Flux-averaged differential cross section in $\pi^0$ momentum, $d\sigma/dp_{\pi^0}(10^{-40}\text{cm}^2/\text{nucleon}/(\text{GeV/c})$, for 1$\pi^0$ production with statistical (stat) and systematic (sys) uncertainties.
Flux-averaged differential cross section in $\pi^0$ angle, $d\sigma/d\theta_{\pi^0}(10^{-42}\text{cm}^2/\text{nucleon}/\text{deg.})$, for 1$\pi^0$ production with statistical (stat) and systematic (sys) uncertainties.
The MINERvA collaboration reports a novel study of neutrino-nucleus charged-current deep inelastic scattering (DIS) using the same neutrino beam incident on targets of polystyrene, graphite, iron, and lead. Results are presented as ratios of C, Fe, and Pb to CH. The ratios of total DIS cross sections as a function of neutrino energy and flux-integrated differential cross sections as a function of the Bjorken scaling variable x are presented in the neutrino-energy range of 5 - 50 GeV. Good agreement is found between the data and predicted ratios, based on charged-lepton nucleus scattering, at medium x and low neutrino energies. However, the data rate appears depleted in the vicinity of the nuclear shadowing region, x < 0.1. This apparent deficit, reflected in the DIS cross-section ratio at high neutrino energy , is consistent with previous MINERvA observations and with the predicted onset of nuclear shadowing with the the axial-vector current in neutrino scattering.
Ratio of the total DIS cross section on C to CH as a function of $E_\nu$.
Statistical error matrix of the ratio of the total DIS cross section on C to CH as a function of $E_\nu$.
Systematic error matrix of the ratio of the total DIS cross section on C to CH as a function of $E_\nu$.
Mid-rapidity open charm spectra from direct reconstruction of $D^{0}$($\bar{D^0}$)$\to K^{\mp}\pi^{\pm}$ in d+Au collisions and indirect electron/positron measurements via charm semileptonic decays in p+p and d+Au collisions at \srt = 200 GeV are reported. The $D^{0}$($\bar{D^0}$) spectrum covers a transverse momentum ($p_T$) range of 0.1 $<p_T<$ 3 \GeVc whereas the electron spectra cover a range of 1 $<p_T<$ 4 GeV/$c$. The electron spectra show approximate binary collision scaling between p+p and d+Au collisions. From these two independent analyses, the differential cross section per nucleon-nucleon binary interaction at mid-rapidity for open charm production from d+Au collisions at RHIC is $d\sigma^{NN}_{c\bar{c}}/dy$=0.30$\pm$0.04 (stat.)$\pm$0.09(syst.) mb. The results are compared to theoretical calculations. Implications for charmoniumm results in A+A collisions are discussed.
Inclusive electrons yield versus transverse momentum in D+AU collisions Data points at PT = 2.2, 2.7 and 3.5 GeV/c was obtained using only the TPC (Time Projection Chamber) and cover a pseudo-rapidity range of -1<eta<1, while other points were obtained using both a prototypeTime-of-Flight System and the TPC and cover a pseudo-rapidity range of -1<eta<0.
Inclusive electrons yield versus transverse momentum in P+P collisions.
D0 yield versus transverse momentum in D+AU collisions.
We report the measurement of charged $D^*$ mesons in inclusive jets produced in proton-proton collisions at a center of mass energy $\sqrt{s}$ = 200 GeV with the STAR experiment at RHIC. For $D^{*}$ mesons with fractional momenta $0.2 < z < 0.5$ in inclusive jets with 11.5 GeV mean transverse energy, the production rate is found to be $N(D^{*+}+D^{*-})/N(\mathrm{jet}) = 0.015 \pm 0.008 (\mathrm{stat}) \pm 0.007 (\mathrm{sys})$. This rate is consistent with perturbative QCD evaluation of gluon splitting into a pair of charm quarks and subsequent hadronization.
D*+-/jet azimuthal correlations. Delta Phi represents the difference in azimuthal angle between D*+- (of 2<Pt<10 GeV/c) and the jet's (of 8<Pt<20 GeV/c) axis.
Production rate of D*+- mesons with fractional longitudinal momenta 0.2<z<0.5 (z = Pl(D*+-)/Ejet, Pl is the momentum projection on the jet axis and Ejet is the total jet energy) in inclusive jets of 11.5 Gev mean transverse energy.
The STAR collaboration at RHIC presents measurements of \Jpsi$\to{e^+e^-}$ at mid-rapidity and high transverse momentum ($p_T>5$ GeV/$c$) in \pp and central \cucu collisions at \sNN = 200 GeV. The inclusive \Jpsi production cross section for \cucu collisions is found to be consistent at high $p_T$ with the binary collision-scaled cross section for \pp collisions, in contrast to previous measurements at lower $p_T$, where a suppression of \Jpsi production is observed relative to the expectation from binary scaling. Azimuthal correlations of $J/\psi$ with charged hadrons in \pp collisions provide an estimate of the contribution of $B$-meson decays to \Jpsi production of $13% \pm 5%$.
J/psi differential production cross section in sqrt(s).
J/psi transverse momentum distribution in sqrt(s).
J/psi transverse momentum distribution in sqrt(s).
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