Neutrino-Induced Coherent π

MINERvA has measured the ν_{µ}-induced coherent π^{+} cross section simultaneously in hydrocarbon (CH), graphite (C), iron (Fe), and lead (Pb) targets using neutrinos from 2 to 20 GeV. The measurements exceed the predictions of the Rein-Sehgal and Berger-Sehgal PCAC based models at multi-GeV ν_{µ} energies and at produced π^{+} energies and angles, E_{π}>1 GeV and θ_{π}<10°. Measurements of the cross-section ratios of Fe and Pb relative to CH reveal the effective A scaling to increase from an approximate A^{1/3} scaling at few GeV to an A^{2/3} scaling for E_{ν}>10 GeV.

Simultaneous Measurement of Muon Neutrino ν_{µ} Charged-Current Single π

Neutrino-induced charged-current single π^{+} production in the Δ(1232) resonance region is of considerable interest to accelerator-based neutrino oscillation experiments. In this Letter, high statistic differential cross sections are reported for the semiexclusive reaction ν_{µ}A→µ^{-}π^{+}+ nucleon(s) on scintillator, carbon, water, iron, and lead targets recorded by MINERvA using a wideband ν_{µ} beam with ⟨E_{ν}⟩≈6 GeV. Suppression of the cross section at low Q^{2} and enhancement of low T_{π} are observed in both light and heavy nuclear targets compared with phenomenological models used in current neutrino interaction generators. The cross sections per nucleon for iron and lead compared with CH across the kinematic variables probed are 0.8 and 0.5 respectively, a scaling which is also not predicted by current generators.

Simultaneous Measurement of ν_{µ} Quasielasticlike Cross Sections on CH, C, H_{2}O, Fe, and Pb as a Function of Muon Kinematics at MINERvA.

This Letter presents the first simultaneous measurement of the quasielasticlike neutrino-nucleus cross sections on C, water, Fe, Pb, and scintillator (hydrocarbon or CH) as a function of longitudinal and transverse muon momentum. The ratio of cross sections per nucleon between Pb and CH is always above unity and has a characteristic shape as a function of transverse muon momentum that evolves slowly as a function of longitudinal muon momentum. The ratio is constant versus longitudinal momentum within uncertainties above a longitudinal momentum of 4.5 GeV/c. The cross section ratios to CH for C, water, and Fe remain roughly constant with increasing longitudinal momentum, and the ratios between water or C to CH do not have any significant deviation from unity. Both the overall cross section level and the shape for Pb and Fe as a function of transverse muon momentum are not reproduced by current neutrino event generators. These measurements provide a direct test of nuclear effects in quasielasticlike interactions, which are major contributors to long-baseline neutrino oscillation data samples.

Measurement of the axial vector form factor from antineutrino-proton scattering.

Scattering of high energy particles from nucleons probes their structure, as was done in the experiments that established the non-zero size of the proton using electron beams1. The use of charged leptons as scattering probes enables measuring the distribution of electric charges, which is encoded in the vector form factors of the nucleon2. Scattering weakly interacting neutrinos gives the opportunity to measure both vector and axial vector form factors of the nucleon, providing an additional, complementary probe of their structure. The nucleon transition axial form factor, FA, can be measured from neutrino scattering from free nucleons, νµn → µ-p and [Formula: see text], as a function of the negative four-momentum transfer squared (Q2). Up to now, FA(Q2) has been extracted from the bound nucleons in neutrino-deuterium scattering3-9, which requires uncertain nuclear corrections10. Here we report the first high-statistics measurement, to our knowledge, of the [Formula: see text] cross-section from the hydrogen atom, using the plastic scintillator target of the MINERvA11 experiment, extracting FA from free proton targets and measuring the nucleon axial charge radius, rA, to be 0.73 ± 0.17 fm. The antineutrino-hydrogen scattering presented here can access the axial form factor without the need for nuclear theory corrections, and enables direct comparisons with the increasingly precise lattice quantum chromodynamics computations12-15. Finally, the tools developed for this analysis and the result presented are substantial advancements in our capabilities to understand the nucleon structure in the weak sector, and also help the current and future neutrino oscillation experiments16-20 to better constrain neutrino interaction models.

Simultaneous Measurement of Proton and Lepton Kinematics in Quasielasticlike ν_{µ}-Hydrocarbon Interactions from 2 to 20 GeV.

Neutrino charged-current quasielastic-like scattering, a reaction category extensively used in neutrino oscillation measurements, probes nuclear effects that govern neutrino-nucleus interactions. This Letter reports the first measurement of the triple-differential cross section for ν_{µ} quasielastic-like reactions using the hydrocarbon medium of the MINERvA detector exposed to a wideband beam spanning 2≤E_{ν}≤20 GeV. The measurement maps the correlations among transverse and longitudinal muon momenta and summed proton kinetic energies, and compares them to predictions from a state-of-art simulation. Discrepancies are observed that likely reflect shortfalls with modeling of pion and nucleon intranuclear scattering and/or spectator nucleon ejection from struck nuclei. The separate determination of leptonic and hadronic variables can inform experimental approaches to neutrino-energy estimation.

Quantum-Limited Time-Frequency Estimation through Mode-Selective Photon Measurement.

By projecting onto complex optical mode profiles, it is possible to estimate arbitrarily small separations between objects with quantum-limited precision, free of uncertainty arising from overlapping intensity profiles. Here we extend these techniques to the time-frequency domain using mode-selective sum-frequency generation with shaped ultrafast pulses. We experimentally resolve temporal and spectral separations between incoherent mixtures of single-photon level signals ten times smaller than their optical bandwidths with a tenfold improvement in precision over the intensity-only Cramér-Rao bound.

Heralded generation of high-purity ultrashort single photons in programmable temporal shapes.

We experimentally demonstrate a source of nearly pure single photons in arbitrary temporal shapes heralded from a parametric down-conversion (PDC) source at telecom wavelengths. The technology is enabled by the tailored dispersion of in-house fabricated waveguides with shaped pump pulses to directly generate the PDC photons in on-demand temporal shapes. We generate PDC photons in Hermite-Gauss and frequency-binned modes and confirm a minimum purity of 0.81, even for complex temporal shapes.

Harnessing temporal modes for multi-photon quantum information processing based on integrated optics.

In the last few decades, there has been much progress on low loss waveguides, very efficient photon-number detectors and nonlinear processes. Engineered sum-frequency conversion is now at a stage where it allows operation on arbitrary temporal broadband modes, thus making the spectral degree of freedom accessible for information coding. Hereby the information is often encoded into the temporal modes of a single photon. Here, we analyse the prospect of using multi-photon states or squeezed states in different temporal modes based on integrated optics devices. We describe an analogy between mode-selective sum-frequency conversion and a network of spatial beam splitters. Furthermore, we analyse the limits on the achievable squeezing in waveguides with current technology and the loss limits in the conversion process.This article is part of the themed issue 'Quantum technology for the 21st century'.

Uncovering Quantum Correlations with Time-Multiplexed Click Detection.

We report on the implementation of a time-multiplexed click detection scheme to probe quantum correlations between different spatial optical modes. We demonstrate that such measurement setups can uncover nonclassical correlations in multimode light fields even if the single mode reductions are purely classical. The nonclassical character of correlated photon pairs, generated by a parametric down-conversion, is immediately measurable employing the theory of click counting instead of low-intensity approximations with photoelectric detection models. The analysis is based on second- and higher-order moments, which are directly retrieved from the measured click statistics, for relatively high mean photon numbers. No data postprocessing is required to demonstrate the effects of interest with high significance, despite low efficiencies and experimental imperfections. Our approach shows that such novel detection schemes are a reliable and robust way to characterize quantum-correlated light fields for practical applications in quantum communications.

Endometrial biopsy using a plastic curette (Mi-Mark).

Using soft (Mi-Mark) and sharp (Novak) curette endometrial biopsies were performed for the purpose of cancer screening and ovulation detection in five and 44 cases, respectively. The new devised plastic curette (Mi-Mark) when compared to the metal curette proved to be equally effective in obtaining an adequate endometrial sample for histologic evaluation. Due to the flexibility of the plastic curette endometrial biopsies were performed atraumatically and with the least amount of pain in most cases.

Sodium bicarbonate douching for improvement of the postcoital test.

In the hope of improving sperm survival within the cervical mucus, 93 infertile patients with unfavorable postcoital tests were advised to douche with a solution of sodium bicarbonate 30 to 60 minutes prior to sexual intercourse. In most patients observed, the repeatedly poor postcoital test improved remarkably, and 31 pregnancies have been achieved. In the majority of patients, the postcoital test was repeated on 2 subsequent days (without and with the benefit of sodium bicarbonate douching) with astonishing differences in the test results. In addition to pH changes, sodium bicarbonate douching resulted in significant alteration of the cervical mucus electrolyte components (detected by scanning electron microscopy and energy-dispersive x-ray analysis). The possible modes of action of sodium bicarbonate douching are fully analyzed.