We present a measurement of neutral pion production in charged-current interactions using data recorded with the MicroBooNE detector exposed to Fermilab's booster neutrino beam. The signal comprises ...one muon, one neutral pion, any number of nucleons, and no charged pions. Studying neutral pion production in the MicroBooNE detector provides an opportunity to better understand neutrino-argon interactions, and is crucial for future accelerator-based neutrino oscillation experiments. Using a dataset corresponding to \(6.86 \times 10^{20}\) protons on target, we present single-differential cross sections in muon and neutral pion momenta, scattering angles with respect to the beam for the outgoing muon and neutral pion, as well as the opening angle between the muon and neutral pion. Data extracted cross sections are compared to generator predictions. We report good agreement between the data and the models for scattering angles, except for an over-prediction by generators at muon forward angles. Similarly, the agreement between data and the models as a function of momentum is good, except for an underprediction by generators in the medium momentum ranges, \(200-400\) MeV for muons and \(100-200\) MeV for pions.
Charged-current neutrino interactions with final states containing zero mesons and at least one proton are of high interest for current and future accelerator-based neutrino oscillation experiments. ...Using the Booster Neutrino Beam and the MicroBooNE detector at Fermi National Accelerator Laboratory, we have obtained the first double-differential cross section measurements of this channel for muon neutrino scattering on an argon target with a proton momentum threshold of 0.25 GeV/c. We also report a flux-averaged total cross section of \(\sigma = (11.8 \pm 1.2) \times 10^{-38}\) cm\(^2\) / Ar and several single-differential measurements which extend and improve upon previous results. Statistical and systematic uncertainties are quantified with a full treatment of correlations across 359 kinematic bins, including correlations between distributions describing different observables. The resulting data set provides the most detailed information obtained to date for testing models of mesonless neutrino-argon scattering.
We present the first measurement of the angular distribution for the exclusive process p¯p→ψ(2S)→e+e− based on a sample of 6844 events collected by the Fermilab E835 experiment. We find that the ...angular distribution is well described by the expected functional form dNdcosθ∗∝1+λcos2θ∗, where θ∗ is the angle between the antiproton and the electron in the center of mass frame, with λ=0.67±0.15(stat)±0.04(sys). The measured value for λ implies a small but non-zero ψ(2S) helicity 0 formation amplitude in p¯p, comparable to what is observed in J/ψ decays to baryon pairs.
We present the first search for heavy neutral leptons (HNL) decaying into \(\nu e^+e^-\) or \(\nu\pi^0\) final states in a liquid-argon time projection chamber using data collected with the ...MicroBooNE detector. The data were recorded synchronously with the NuMI neutrino beam from Fermilab's Main Injector corresponding to a total exposure of \(7.01 \times 10^{20}\) protons on target. We set upper limits at the \(90\%\) confidence level on the mixing parameter \(\lvert U_{\mu 4}\rvert^2\) in the mass ranges \(10\le m_{\rm HNL}\le 150\) MeV for the \(\nu e^+e^-\) channel and \(150\le m_{\rm HNL}\le 245\) MeV for the \(\nu\pi^0\) channel, assuming \(\lvert U_{e 4}\rvert^2 = \lvert U_{\tau 4}\rvert^2 = 0\). These limits represent the most stringent constraints in the mass range \(35<m_{\rm HNL}<175\) MeV and the first constraints from a direct search for \(\nu\pi^0\) decays.
We have studied the
3P
J
(
χ
c
) states of charmonium in formation by antiproton–proton annihilations in experiment E835 at the Fermilab Antiproton Source. We report new measurements of the mass, ...width, and
B
(
χ
c
J
→
p
¯
p
)
Γ
(
χ
c
J
→
J
/
ψ
+
anything
)
for the
χ
c
1
and
χ
c
2
by means of the inclusive reaction
p
¯
p
→
χ
c
J
→
J
/
ψ
+
anything
→
(
e
+
e
−
)
+
anything
. Using the subsample of events where
χ
c
J
→
γ
+
J
/
ψ
→
γ
+
(
e
+
e
−
)
is fully reconstructed, we derive
B
(
χ
c
J
→
p
¯
p
)
Γ
(
χ
c
J
→
J
/
ψ
+
γ
)
. We summarize the results of the E760 (updated) and E835 measurements of mass, width and
B
(
χ
c
J
→
p
¯
p
)
Γ
(
χ
c
J
→
J
/
ψ
+
γ
)
(
J
=
0
,
1
,
2
) and discuss the significance of these measurements.
Hepatocytes isolated from 101 biopsies were examined for membrane-bound IgG. The sera of the patients were tested for anti-liver-specific lipoprotein by radioimmunoassay and for liver membrane ...autoantibody (by indirect immunofluorescence on isolated rabbit hepatocytes. The seven patients with normal liver or minor nonspecific alterations were negative for membrane IgG and serum antibodies. Membrane IgG with granular distribution was found in 41 patients 21 hepatitis B virus-related chronic active hepatitis (CAH), 3 cryptogenic CAH, 3 chronic persistent hepatitis, 6 prolonged viral hepatitis, 1 alcoholic cirrhosis, and 6 primary biliary cirrhosis. Membrane IgG with linear fluorescence pattern was detected in 12 cases (4 autoimmune CAH, 3 HBsAg-positive CAH, 2 alcoholic cirrhosis, 1 anti-HBc positive CAH, 1 cryptogenic CAH, and 1 prolonged viral hepatitis). A strong association between granular IgG and serum HBsAg was found. Nuclear localization of IgG was found in 34 patients and correlated with the positivity of granular membrane IgG. The highest prevalence of anti-liver-specific lipoprotein was found in primary biliary cirrhosis and autoimmune CAH cases which were also positive for liver membrane autoantibody. No relationship was found between the presence of membrane IgG and circulating liver-specific autoantibodies. Membrane IgG and anti-liver-specific lipoprotein correlated with the presence of moderate and severe portal inflammatory infiltration but not with piecemeal necrosis or transaminase levels. Eleven of the twelve patients with linear membrane IgG presented chronic active liver disease with moderate to severe signs of liver damage. Therefore, it is suggested that, while granular membrane IgGs are related to hepatitis B virus, antigenic expression on the hepatocyte surface and/or the presence of immune complexes, linear membrane IgG could play a role in the immunopathogenesis of liver cell damage particularly in "autoimmune" cases which present high percentages of positive cells liver-specific autoantibodies.
Fermilab experiment E835 has observed (-)pp annihilation production of the charmonium state chi(c0) and its subsequent decay into pi(0)pi(0). Although the resonant amplitude is an order of magnitude ...smaller than that of the nonresonant continuum production of pi(0)pi(0), an enhanced interference signal is evident. A partial wave expansion is used to extract physics parameters. The amplitudes J=0 and 2, of comparable strength, dominate the expansion. Both are accessed by L=1 in the entrance (-)pp channel. The product of the input and output branching fractions is determined to be B((-)pp-->chi(c0))xB(chi(c0)-->pi(0)pi(0))=(5.09+/-0.81+/-0.25)x10(-7).
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