arXiv subjects

J. -Y. Li

Publications and source records attributed to J. -Y. Li.

At least 55 records · Page 3Linked to original sources

arXiv2024

First measurement of $η$ production in neutrino interactions on argon with MicroBooNE

We present a measurement of $η$ production from neutrino interactions on argon with the MicroBooNE detector. The modeling of resonant neutrino interactions on argon is a critical aspect of the neutrino oscillation physics program being carried out by the DUNE and Short Baseline Neutrino programs. $η$ production in neutrino interactions provides a powerful new probe of resonant interactions, complementary to pion channels, and is particularly suited to the study of higher-order resonances beyond the $Δ(1232)$. We measure a flux-integrated cross section for neutrino-induced $η$ production on argon of $3.22 \pm 0.84 \; \textrm{(stat.)} \pm 0.86 \; \textrm{(syst.)}$ $10^{-41}{\textrm{cm}}^{2}$/nucleon. By demonstrating the successful reconstruction of the two photons resulting from $η$ production, this analysis enables a novel calibration technique for electromagnetic showers in GeV accelerator neutrino experiments.

hep-ex↗

arXiv2024

Measurement of double-differential cross sections for mesonless charged-current muon neutrino interactions on argon with final-state protons using the MicroBooNE detector

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 $σ= (11.8 \pm 1.2) \times 10^{-38}$ 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.

hep-ex↗

arXiv2024

Measurement of ambient radon progeny decay rates and energy spectra in liquid argon using the MicroBooNE detector

We report measurements of radon progeny in liquid argon within the MicroBooNE time projection chamber (LArTPC). The presence of specific radon daughters in MicroBooNE's 85 metric tons of active liquid argon bulk is probed with newly developed charge-based low-energy reconstruction tools and analysis techniques to detect correlated $^{214}$Bi-$^{214}$Po radioactive decays. Special datasets taken during periods of active radon doping enable new demonstrations of the calorimetric capabilities of single-phase neutrino LArTPCs for $β$ and $α$ particles with electron-equivalent energies ranging from 0.1 to 3.0 MeV. By applying $^{214}$Bi-$^{214}$Po detection algorithms to data recorded over a 46-day period, no statistically significant presence of radioactive $^{214}$Bi is detected, and a limit on the activity is placed at $<0.35$ mBq/kg at the 95% confidence level. This bulk $^{214}$Bi radiopurity limit -- the first ever reported for a liquid argon detector incorporating liquid-phase purification -- is then further discussed in relation to the targeted upper limit of 1 mBq/kg on bulk $^{222}$Rn activity for the DUNE neutrino detector.

hep-ex↗

arXiv2024

Physical properties of asteroid Dimorphos as derived from the DART impact

On September 26, 2022, NASA's Double Asteroid Redirection Test (DART) mission successfully impacted Dimorphos, the natural satellite of the binary near-Earth asteroid (65803) Didymos. Numerical simulations of the impact provide a means to explore target surface material properties and structures, consistent with the observed momentum deflection efficiency, ejecta cone geometry, and ejected mass. Our simulation, which best matches observations, indicates that Dimorphos is weak, with a cohesive strength of less than a few pascals (Pa), similar to asteroids (162173) Ryugu and (101955) Bennu. We find that a bulk density of Dimorphos, rhoB, lower than 2400 kg/m3, and a low volume fraction of boulders (<40 vol%) on the surface and in the shallow subsurface, are consistent with measured data from the DART experiment. These findings suggest Dimorphos is a rubble pile that might have formed through rotational mass shedding and re-accumulation from Didymos. Our simulations indicate that the DART impact caused global deformation and resurfacing of Dimorphos. ESA's upcoming Hera mission may find a re-shaped asteroid, rather than a well-defined crater.

astro-ph.EP↗

arXiv2024

Search for heavy neutral leptons in electron-positron and neutral-pion final states with the MicroBooNE detector

We present the first search for heavy neutral leptons (HNL) decaying into $νe^+e^-$ or $νπ^0$ 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 $\lvert U_{μ4}\rvert^2$ in the mass ranges $10\le m_{\rm HNL}\le 150$ MeV for the $νe^+e^-$ channel and $150\le m_{\rm HNL}\le 245$ MeV for the $νπ^0$ channel, assuming $\lvert U_{e 4}\rvert^2 = \lvert U_{τ4}\rvert^2 = 0$. 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 $νπ^0$ decays.

hep-ex↗

arXiv2023

First demonstration of $\mathcal{O}(1\,\text{ns})$ timing resolution in the MicroBooNE liquid argon time projection chamber

MicroBooNE is a neutrino experiment located in the Booster Neutrino Beamline (BNB) at Fermilab, which collected data from 2015 to 2021. MicroBooNE's liquid argon time projection chamber (LArTPC) is accompanied by a photon detection system consisting of 32 photomultiplier tubes used to measure the argon scintillation light and determine the timing of neutrino interactions. Analysis techniques combining light signals and reconstructed tracks are applied to achieve a neutrino interaction time resolution of $\mathcal{O}(1\,\text{ns})$. The result obtained allows MicroBooNE to access the ns neutrino pulse structure of the BNB for the first time. The timing resolution achieved will enable significant enhancement of cosmic background rejection for all neutrino analyses. Furthermore, the ns timing resolution opens new avenues to search for long-lived-particles such as heavy neutral leptons in MicroBooNE, as well as in future large LArTPC experiments, namely the SBN program and DUNE.

hep-ex↗

arXiv2023

First measurement of quasi-elastic $Λ$ baryon production in muon anti-neutrino interactions in the MicroBooNE detector

We present the first measurement of the cross section of Cabibbo-suppressed $Λ$ baryon production, using data collected with the MicroBooNE detector when exposed to the neutrinos from the Main Injector beam at the Fermi National Accelerator Laboratory. The data analyzed correspond to $2.2 \times 10^{20}$ protons on target of neutrino mode running and $4.9 \times 10^{20}$ protons on target of anti-neutrino mode running. An automated selection is combined with hand scanning, with the former identifying five candidate $Λ$ production events when the signal was unblinded, consistent with the GENIE prediction of $5.3 \pm 1.1$ events. Several scanners were employed, selecting between three and five events, compared with a prediction from a blinded Monte Carlo simulation study of $3.7 \pm 1.0$ events. Restricting the phase space to only include $Λ$ baryons that decay above MicroBooNE's detection thresholds, we obtain a flux averaged cross section of $2.0^{+2.2}_{-1.7} \times 10^{-40}$ cm$^2/$Ar, where statistical and systematic uncertainties are combined.

hep-ex↗

arXiv2022

Measurement of neutral current single $π^0$ production on argon with the MicroBooNE detector

We report the first measurement of $π^0$ production in neutral current (NC) interactions on argon with average neutrino energy of $\lesssim1$~GeV. We use data from the MicroBooNE detector's 85-tonne active volume liquid argon time projection chamber situated in Fermilab's Booster Neutrino Beam and exposed to $5.89\times10^{20}$ protons on target for this measurement. Measurements of NC $π^0$ events are reported for two exclusive event topologies without charged pions. Those include a topology with two photons from the decay of the $π^0$ and one proton and a topology with two photons and zero protons. Flux-averaged cross-sections for each exclusive topology and for their semi-inclusive combination are extracted (efficiency-correcting for two-plus proton final states), and the results are compared to predictions from the \textsc{genie}, \textsc{neut}, and \textsc{NuWro} neutrino event generators. We measure cross sections of $1.243\pm0.185$ (syst) $\pm0.076$ (stat), $0.444\pm0.098\pm0.047$, and $0.624\pm0.131\pm0.075$ $[10^{-38}\textrm{cm}^2/\textrm{Ar}]$ for the semi-inclusive NC$π^0$, exclusive NC$π^0$+1p, and exclusive NC$π^0$+0p processes, respectively.

hep-ex↗

arXiv2022

Search for long-lived heavy neutral leptons and Higgs portal scalars decaying in the MicroBooNE detector

We present a search for long-lived Higgs portal scalars (HPS) and heavy neutral leptons (HNL) decaying in the MicroBooNE liquid-argon time projection chamber. The measurement is performed using data collected synchronously with the NuMI neutrino beam from Fermilab's Main Injector with a total exposure corresponding to $7.01 \times 10^{20}$ protons on target. We set upper limits at the $90\%$ confidence level on the mixing parameter $\lvert U_{μ4}\rvert^2$ ranging from $\lvert U_{μ4}\rvert^2<12.9\times 10^{-8}$ for Majorana HNLs with a mass of $m_{\rm HNL}=246$ MeV to $\lvert U_{μ4}\rvert^2<0.92 \times 10^{-8}$ for $m_{\rm HNL}=385$ MeV, assuming $\lvert U_{e 4}\rvert^2 = \lvert U_{τ4}\rvert^2 = 0$ and HNL decays into $μ^\pmπ^\mp$ pairs. These limits on $\lvert U_{μ4}\rvert^2$ represent an order of magnitude improvement in sensitivity compared to the previous MicroBooNE result. We also constrain the scalar-Higgs mixing angle $θ$ by searching for HPS decays into $μ^+μ^-$ final states, excluding a contour in the parameter space with lower bounds of $θ^2<31.3 \times 10^{-9}$ for $m_{\rm HPS}=212$ GeV and $θ^2<1.09 \times 10^{-9}$ for $m_{\rm HPS}=275$ GeV. These are the first constraints on the scalar-Higgs mixing angle $θ$ from a dedicated experimental search in this mass range.

hep-ex↗

arXiv2022

First constraints on light sterile neutrino oscillations from combined appearance and disappearance searches with the MicroBooNE detector

We present a search for eV-scale sterile neutrino oscillations in the MicroBooNE liquid argon detector, simultaneously considering all possible appearance and disappearance effects within the $3+1$ active-to-sterile neutrino oscillation framework. We analyze the neutrino candidate events for the recent measurements of charged-current $ν_e$ and $ν_μ$ interactions in the MicroBooNE detector, using data corresponding to an exposure of 6.37$\times$10$^{20}$ protons on target from the Fermilab booster neutrino beam. We observe no evidence of light sterile neutrino oscillations and derive exclusion contours at the $95\%$ confidence level in the plane of the mass-squared splitting $Δm^2_{41}$ and the sterile neutrino mixing angles $θ_{μe}$ and $θ_{ee}$, excluding part of the parameter space allowed by experimental anomalies. Cancellation of $ν_e$ appearance and $ν_e$ disappearance effects due to the full $3+1$ treatment of the analysis leads to a degeneracy when determining the oscillation parameters, which is discussed in this paper and will be addressed by future analyses.

hep-ex↗

arXiv2022

Observation of Radon Mitigation in MicroBooNE by a Liquid Argon Filtration System

The MicroBooNE liquid argon time projection chamber (LArTPC) maintains a high level of liquid argon purity through the use of a filtration system that removes electronegative contaminants in continuously-circulated liquid, recondensed boil off, and externally supplied argon gas. We use the MicroBooNE LArTPC to reconstruct MeV-scale radiological decays. Using this technique we measure the liquid argon filtration system's efficacy at removing radon. This is studied by placing a 500 kBq $^{222}$Rn source upstream of the filters and searching for a time-dependent increase in the number of radiological decays in the LArTPC. In the context of two models for radon mitigation via a liquid argon filtration system, a slowing mechanism and a trapping mechanism, MicroBooNE data supports a radon reduction factor of greater than 99.999% or 97%, respectively. Furthermore, a radiological survey of the filters found that the copper-based filter material was the primary medium that removed the $^{222}$Rn. This is the first observation of radon mitigation in liquid argon with a large-scale copper-based filter and could offer a radon mitigation solution for future large LArTPCs.

physics.ins-det↗

arXiv2022

Differential cross section measurement of charged current $ν_{e}$ interactions without final-state pions in MicroBooNE

In this letter we present the first measurements of an exclusive electron neutrino cross section with the MicroBooNE experiment using data from the Booster Neutrino Beamline at Fermilab. These measurements are made for a selection of charged-current electron neutrinos without final-state pions. Differential cross sections are extracted in energy and angle with respect to the beam for the electron and the leading proton. The differential cross section as a function of proton energy is measured using events with protons both above and below the visibility threshold. This is done by including a separate selection of electron neutrino events without reconstructed proton candidates in addition to those with proton candidates. Results are compared to the predictions from several modern generators, and we find the data agrees well with these models. The data shows best agreement, as quantified by $p$-value, with the generators that predict a lower overall cross section, such as GENIE v3 and NuWro.

hep-ex↗

arXiv2022

Cosmic ray muon clustering for the MicroBooNE liquid argon time projection chamber using sMask-RCNN

In this article, we describe a modified implementation of Mask Region-based Convolutional Neural Networks (Mask-RCNN) for cosmic ray muon clustering in a liquid argon TPC and applied to MicroBooNE neutrino data. Our implementation of this network, called sMask-RCNN, uses sparse submanifold convolutions to increase processing speed on sparse datasets, and is compared to the original dense version in several metrics. The networks are trained to use wire readout images from the MicroBooNE liquid argon time projection chamber as input and produce individually labeled particle interactions within the image. These outputs are identified as either cosmic ray muon or electron neutrino interactions. We find that sMask-RCNN has an average pixel clustering efficiency of 85.9% compared to the dense network's average pixel clustering efficiency of 89.1%. We demonstrate the ability of sMask-RCNN used in conjunction with MicroBooNE's state-of-the-art Wire-Cell cosmic tagger to veto events containing only cosmic ray muons. The addition of sMask-RCNN to the Wire-Cell cosmic tagger removes 70% of the remaining cosmic ray muon background events at the same electron neutrino event signal efficiency. This event veto can provide 99.7% rejection of cosmic ray-only background events while maintaining an electron neutrino event-level signal efficiency of 80.1%. In addition to cosmic ray muon identification, sMask-RCNN could be used to extract features and identify different particle interaction types in other 3D-tracking detectors.

hep-ex↗

arXiv2021

Density dependence of the excitation gaps in an undoped Si/SiGe double-quantum-well heterostructure

We report low-temperature magneto-transport measurements of an undoped Si/SiGe asymmetric double quantum well heterostructure. The density in both layers is tuned independently utilizing a top and a bottom gate, allowing the investigation of quantum wells at both imbalanced and matched densities. Integer quantum Hall states at total filling factor $ν_{\text{T}} = 1$ and $ν_{\text{T}} = 2$ are observed in both density regimes, and the evolution of their excitation gaps is reported as a function of density. The $ν_{\text{T}} = 1$ gap evolution departs from the behavior generally observed for valley splitting in the single layer regime. Furthermore, by comparing the $ν_{\text{T}} = 2$ gap to the single particle tunneling energy, $Δ_{\text{SAS}}$, obtained from Schrödinger-Poisson (SP) simulations, evidence for the onset of spontaneous inter-layer coherence (SIC) is observed for a relative filling fraction imbalance smaller than ${\sim}50\%$

cond-mat.mes-hall↗

arXiv2021

The eROSITA Final Equatorial-Depth Survey (eFEDS): The first archetypal Quasar in the feedback phase discovered by eROSITA

Theoretical models of galaxy-AGN co-evolution ascribe an important role for the feedback process to a short, luminous, obscured, and dust-enshrouded phase during which the accretion rate of the SMBH is expected to be at its maximum and the associated AGN-driven winds are also predicted to be maximally developed. To test this scenario, we have isolated a text-book candidate from the eROSITA Final Equatorial-Depth Survey (eFEDS) obtained within the Performance and Verification program of the eROSITA telescope on board Spectrum Roentgen Gamma. From an initial catalog of 246 hard X-ray selected sources matched with the photometric and spectroscopic information available within the eROSITA and Hyper Suprime-Cam consortia, three candidates Quasars in the feedback phase have been isolated applying the diagnostic proposed in Brusa et al. (2015). Only one source (eFEDSU J091157.5+014327) has a spectrum already available (from SDSS-DR16, z=0.603) and it unambiguously shows the presence of a broad component (FWHM~1650 km/s) in the [OIII]5007 line. The associated observed L_[OIII] is ~2.6x10^{42} erg/s, one to two orders of magnitude larger than that observed in local Seyferts and comparable to those observed in a sample of z~0.5 Type 1 Quasars. From the multiwavelength data available we derive an Eddington Ratio (L_bol/L_Edd) of ~0.25, and a bolometric correction in the hard X-ray of k_bol~10, lower than those observed for objects at similar bolometric luminosity. The presence of an outflow, the high X-ray luminosity and moderate X-ray obscuration (L_X~10^44.8 erg/s, N_H~2.7x10^22 cm^-2) and the red optical color, all match the prediction of quasars in the feedback phase from merger driven models. Forecasting to the full eROSITA all-sky survey with its spectroscopic follow-up, we predict that by the end of 2024 we will have a sample of few hundreds such objects at z=0.5-2.

astro-ph.HE↗

arXiv2021

Bennu's global surface and two candidate sample sites characterized by spectral clustering of OSIRIS-REx multispectral images

The OSIRIS-REx spacecraft encountered the asteroid (101955) Bennu on December 3, 2018, and has since acquired extensive data from the payload of scientific instruments on board. In 2019, the OSIRIS-REx team selected primary and backup sample collection sites, called Nightingale and Osprey, respectively. On October 20, 2020, OSIRIS-REx successfully collected material from Nightingale. In this work, we apply an unsupervised machine learning classification through the K-Means algorithm to spectrophotometrically characterize the surface of Bennu, and in particular Nightingale and Osprey. We first analyze a global mosaic of Bennu, from which we find four clusters scattered across the surface, reduced to three when we normalize the images at 550 nm. The three spectral clusters are associated with boulders and show significant differences in spectral slope and UV value. We do not see evidence of latitudinal non-uniformity, which suggests that Bennu's surface is well-mixed. In our higher-resolution analysis of the primary and backup sample sites, we find three representative normalized clusters, confirming an inverse correlation between reflectance and spectral slope (the darkest areas being the reddest ones) and between b' normalized reflectance and slope. Nightingale and Osprey are redder than the global surface of Bennu by more than $1σ$ from average, consistent with previous findings, with Nightingale being the reddest ($S' = (- 0.3 \pm 1.0) \times 10^{- 3}$ percent per thousand angstroms). We see hints of a weak absorption band at 550 nm at the candidate sample sites and globally, which lends support to the proposed presence of magnetite on Bennu.

astro-ph.EP↗

arXiv2020

Resolved Spectrophotometric Properties of the Ceres Surface from Dawn Framing Camera Images

We present a global spectrophotometric characterization of the Ceres surface using Dawn Framing Camera (FC) images. We identify the photometric model that yields the best results for photometrically correcting images. Corrected FC images acquired on approach to Ceres were assembled into global maps of albedo and color. Generally, albedo and color variations on Ceres are muted. The albedo map is dominated by a large, circular feature in Vendimia Planitia, known from HST images (Li et al., 2006), and dotted by smaller bright features mostly associated with fresh-looking craters. The dominant color variation over the surface is represented by the presence of "blue" material in and around such craters, which has a negative spectral slope over the visible wavelength range when compared to average terrain. We also mapped variations of the phase curve by employing an exponential photometric model, a technique previously applied to asteroid Vesta (Schröder et al., 2013b). The surface of Ceres scatters light differently from Vesta in the sense that the ejecta of several fresh-looking craters may be physically smooth rather than rough. High albedo, blue color, and physical smoothness all appear to be indicators of youth. The blue color may result from the desiccation of ejected material that is similar to the phyllosilicates/water ice mixtures in the experiments of Poch et al. (2016). The physical smoothness of some blue terrains would be consistent with an initially liquid condition, perhaps as a consequence of impact melting of subsurface water ice. We find red terrain (positive spectral slope) near Ernutet crater, where De Sanctis et al. (2017) detected organic material. The spectrophotometric properties of the large Vendimia Planitia feature suggest it is a palimpsest, consistent with the Marchi et al. (2016) impact basin hypothesis. The central bright area in Occator crater, Cerealia...

astro-ph.EP↗

arXiv2020

The carbon monoxide-rich interstellar comet 2I/Borisov

Interstellar comets offer direct samples of volatiles from distant protoplanetary disks. 2I/Borisov is the first notably active interstellar comet discovered in our solar system[1]. Comets are condensed samples of the gas, ice, and dust that were in a star's protoplanetary disk during the formation of its planets and inform our understanding on how chemical compositions and abundances vary with distance from the central star. Their orbital migration moves volatiles[2], organic material, and prebiotic chemicals in their host system[3]. In our solar system, hundreds of comets have been observed remotely, and a few have been studied up close by space missions[4]. However, knowledge of extrasolar comets has been limited to what could be gleaned from distant, unresolved observations of cometary regions around other stars, with only one detection of carbon monoxide[5]. Here we report that the coma of 2I/Borisov contains significantly more CO than H2O gas, with abundances of at least 173%, more than three times higher than previously measured for any comet in the inner (<2.5 au) solar system[4]. Our ultraviolet observations of 2I/Borisov provide the first glimpse into the ice content and chemical composition of the protoplanetary disk of another star that is substantially different from our own.

astro-ph.EP↗