arXiv subjects

A. M. Gago

Publications and source records attributed to A. M. Gago.

At least 37 records · Page 2Linked to original sources

arXiv2022

Measurement of inclusive charged-current $ν_{\numu}$ scattering on hydrocarbon at { } 6 GeV with low three-momentum transfer

The \minerva experiment reports double-differential cross-section measurements for $ν_μ$-carbon interactions with three-momentum transfer $|\vec{q}| < 1.2$ GeV obtained with medium energy exposures in the NuMI beam. These measurements are performed as a function of the three-momentum transfer and an energy transfer estimator called the available energy defined as the energy that would be visible in the detector. The double differential cross sections are compared to the GENIE and NuWro predictions along with the modified version of GENIE which incorporates new models for better agreement with earlier measurements from MINERvA. In these measurements, the quasi-elastic, resonance, and multi-nucleon knockout processes appear at different kinematics in this two-dimensional space. The results can be used to improve models for neutrino interactions needed by neutrino oscillation experiments.

hep-ex↗

arXiv2022

Snowmass White Paper: Beyond the Standard Model effects on Neutrino Flavor

Neutrinos are one of the most promising messengers for signals of new physics Beyond the Standard Model (BSM). On the theoretical side, their elusive nature, combined with their unknown mass mechanism, seems to indicate that the neutrino sector is indeed opening a window to new physics. On the experimental side, several long-standing anomalies have been reported in the past decades, providing a strong motivation to thoroughly test the standard three-neutrino oscillation paradigm. In this Snowmass21 white paper, we explore the potential of current and future neutrino experiments to explore BSM effects on neutrino flavor during the next decade.

hep-ph↗

arXiv2022

Simultaneous measurement of proton and lepton kinematics in quasielastic-like $ν_μ$-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 wide-band beam spanning 2 $\leq$ E$_ν\leq$ 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.

hep-ex↗

arXiv2022

Use of Neutrino Scattering Events with Low Hadronic Recoil to Inform Neutrino Flux and Detector Energy Scale

Charged-current neutrino interactions with low hadronic recoil ("low-nu") have a cross-section that is approximately constant versus neutrino energy. These interactions have been used to measure the shape of neutrino fluxes as a function of neutrino energy at accelerator-based neutrino experiments such as CCFR, NuTeV, MINOS and MINERvA. In this paper, we demonstrate that low-nu events can be used to measure parameters of neutrino flux and detector models and that utilization of event distributions over the upstream detector face can discriminate among parameters that affect the neutrino flux model. From fitting a large sample of low-nu events obtained by exposing MINERvA to the NuMI medium-energy beam, we find that the best-fit flux parameters are within their a priori uncertainties, but the energy scale of muons reconstructed in the MINOS detector is shifted by 3.6% (or 1.8 times the a priori uncertainty on that parameter). These fit results are now used in all MINERvA cross-section measurements, and this technique can be applied by other experiments operating at MINERvA energies, such as DUNE.

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arXiv2022

Neutral pion reconstruction using machine learning in the MINERvA experiment at $\langle E_ν\rangle \sim 6$ GeV

This paper presents a novel neutral-pion reconstruction that takes advantage of the machine learning technique of semantic segmentation using MINERvA data collected between 2013-2017, with an average neutrino energy of $6$ GeV. Semantic segmentation improves the purity of neutral pion reconstruction from two gammas from 71\% to 89\% and improves the efficiency of the reconstruction by approximately 40\%. We demonstrate our method in a charged current neutral pion production analysis where a single neutral pion is reconstructed. This technique is applicable to modern tracking calorimeters, such as the new generation of liquid-argon time projection chambers, exposed to neutrino beams with $\langle E_ν\rangle$ between 1-10 GeV. In such experiments it can facilitate the identification of ionization hits which are associated with electromagnetic showers, thereby enabling improved reconstruction of charged-current $ν_e$ events arising from $ν_μ \rightarrow ν_{e}$ appearance.

hep-ex↗

arXiv2022

Constraint of the MINERvA Medium Energy Neutrino Flux using Neutrino-Electron Elastic Scattering

Elastic neutrino scattering on electrons is a precisely-known purely leptonic process that provides a standard candle for measuring neutrino flux in conventional neutrino beams. Using a total sample of 810 neutino-electron scatters after background subtraction, the measurement reduces the normalization uncertainty on the muon neutrino NuMI flux between 2 and 20 GeV from 7.5% to 3.9%. This is the most precise measurement of neutrino-electron scattering to date, will reduce uncertainties on MINERvA's absolute cross section measurements, and demonstrates a technique that can be used in future neutrino beams such as LBNF.

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arXiv2021

Constraining the NuMI neutrino flux using inverse muon decay reactions in MINERvA

Inverse muon decay, $ν_μe^-\toμ^-ν_e$, is a reaction whose cross-section can be predicted with very small uncertainties. It has a neutrino energy threshold of $\approx 11$ GeV and can be used to constrain the high-energy part of the flux in the NuMI neutrino beam. This reaction is the dominant source of events which only contain high-energy muons nearly parallel to the direction of the neutrino beam. We have isolated a sample of hundreds of such events in neutrino and anti-neutrino enhanced beams, and have constrained the predicted high-energy flux.

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arXiv2021

Exploring Neutrino-Nucleus Interactions in the GeV Regime using MINERvA

With the advance of particle accelerator and detector technologies, the neutrino physics landscape is rapidly expanding. As neutrino oscillation experiments enter the intensity and precision frontiers, neutrino-nucleus interaction measurements are providing crucial input. MINERvA is an experiment at Fermilab dedicated to the study of neutrino-nucleus interactions in the regime of incident neutrino energies from one to few GeV. The experiment recorded neutrino and antineutrino scattering data with the NuMI beamline from 2009 to 2019 using the Low-Energy and Medium-Energy beams that peak at 3 GeV and 6 GeV, respectively. This article reviews the broad spectrum of interesting nuclear and particle physics that MINERvA investigations have illuminated. The newfound, detailed knowledge of neutrino interactions with nuclear targets thereby obtained is proving essential to continued progress in the neutrino physics sector.

hep-ex↗

arXiv2021

Uncovering Majorana nature through a precision measurement of $CP$ phase

We show the possibility to discover the neutrino nature by measuring the Majorana CP phase at the DUNE experiment. This phase is turned on by a decoherence environment, possibly originated by physics at the Planck scale. A sizable distortion in the measurement of the Dirac CP violation phase $δ_{\mathrm{CP}}$ is observed at DUNE when compared with T2HK measurement due to decoherence and non-null Majorana phase. Being that, when the measurement of the Majorana phase is performed at DUNE, it reaches a precision of 23 (21) $\%$ for a decoherence parameter $Γ=4.5(5.5)\times 10^{-24} \mathrm{GeV}$ and a Majorana phase equal to $1.5 π$. The latter precision is similar to the one obtained at the T2K experiment at its current Dirac CP violation phase measurement.

hep-ph↗

arXiv2021

Laser spot measurement using cost-affordable devices

We have designed and tested an automated simple setup for quickly measuring the profile and spot size of a Gaussian laser beam using three cost-affordable light sensors. Two profiling techniques were implemented: imaging for the CMOS 2D array (webcam) and scanning knife-edge-like using a single photodiode and an LDR. The methods and sensors were compared to determine their accuracy using lasers of two different wavelengths and technologies. We verify that it is possible to use a low-cost webcam to determine the profile of a laser with 1% uncertainty on the beam waist, 1.5% error on the waistline position, and less than 3% error in determining the minimum spot radius. The photodiode measurement is the most stable since it is not affected by the change in laser intensity. In addition, we show that it is possible to use an inexpensive LDR sensor to estimate the laser spot size with an 11% error.

physics.ins-det↗

arXiv2020

High-statistics measurement of neutrino quasielastic-like scattering at =~6 GeV on a hydrocarbon target

We measure neutrino charged current quasielastic-like scattering on hydrocarbon at high statistics using the wide-band NuMI beam with neutrino energy peaked at 6 GeV. The double-differential cross section is reported in terms of muon longitudinal and transverse momentum. Cross-section contours versus lepton momentum components are approximately described by a conventional generator-based simulation, however discrepancies are observed for transverse momenta above 0.5 GeV/c for longitudinal momentum ranges 3 to 5 GeV/c and 9 to 20 GeV/c. The single differential cross section versus momentum transfer squared ($dσ/dQ_{QE}^2$) is measured over a four-decade range of $Q^2$ that extends to $10~GeV^2$. The cross section turn-over and fall-off in the $Q^2$ range 0.3 to $10~GeV^2$ is not fully reproduced by generator predictions that rely on dipole form factors. Our measurement probes the axial-vector content of the hadronic current and complements the electromagnetic form factor data obtained using electron-nucleon elastic scattering. These results help oscillation experiments because they probe the importance of various correlations and final-state interaction effects within the nucleus, which have different effects on the visible energy in detectors.

hep-ex↗

arXiv2020

Performance of ALICE AD modules in the CERN PS test beam

Two modules of the AD detector have been studied with the test beam at the T10 facility at CERN. The AD detector is made of scintillator pads read out by wave-length shifters (WLS)coupled to clean fibres that carry the produced light to photo-multiplier tubes (PMTs). In ALICE the AD is used to trigger and study the physics of diffractive and ultra-peripheral collisions as well as for a variety of technical tasks like beam-gas background monitoring or as a luminometer. The position dependence of the modules' efficiency has been measured and the effect of hits on the WLS or PMTs has been evaluated. The charge deposited by pions and protons has been measured at different momenta of the test beam. The time resolution is determined as a function of the deposited charge. These results are important ingredients to better understand the AD detector, to benchmark the corresponding simulations, and very importantly they served as a baseline for a similar device, the Forward Diffractive Detector (FDD), being currently built and that will be in operation in ALICE during the LHC Runs 3 and 4.

physics.ins-det↗

arXiv2020

Double-Differential Inclusive Charged-Current $ν_μ$ Cross Sections on Hydrocarbon in MINERvA at $\langle E_ν \rangle \sim$ 3.5 GeV

MINERvA reports inclusive charged-current cross sections for muon neutrinos on hydrocarbon in the NuMI beamline. We measured the double-differential cross section in terms of the longitudinal and transverse muon momenta, as well as the single-differential cross sections in those variables. The data used in this analysis correspond to an exposure of $3.34 \times 10^{20}$ protons on target with a peak neutrino energy of approximately 3.5 GeV. Measurements are compared to the GENIE, NuWro and GiBUU neutrino cross-section predictions, as well as a version of GENIE modified to produce better agreement with prior exclusive MINERvA measurements. None of the models or variants were able to successfully reproduce the data across the entire phase space, which includes areas dominated by each interaction channel.

hep-ex↗

arXiv2020

Impact of Galactic magnetic field modelling on searches of point sources via UHECR-Neutrino correlations

We use the Jansson-Farrar JF12 magnetic field configuration in the context of point source searches by correlating the Telescope Array ultra-high energy cosmic ray data and the IceCube-40 neutrino candidates. As expected, we have found no correlations, thus, we devote this paper to the study of the effect of different magnetic field hypotheses on the minimum neutrino source flux strength required for a $5σ$ discovery and the derived $90\%$ CL upper limits. In this study we present a comparison between the JF12 field, that includes a combination of regular and random field components, and the standard turbulent magnetic field used in previous correlation analyses. For a wider perspective, we also incorporate in our comparison the cases of no magnetic field and the JF12 regular component alone and consider different power law indices $α=2,α=2.3$ for the neutrino point source flux. Collaterally, a novel parameterisation of the JF12 random component is introduced. We have observed that the discovery potential for a point source search is sensitive to changes in the magnetic field assumptions, being the difference between the models mentioned before between 15% and 26%.

astro-ph.HE↗

arXiv2020

A roadmap for searching cosmic rays correlated with the extraterrestrial neutrinos seen at IceCube

We have built regions in a Sky map where it should be expected the arrival of 120 EeV ultrahigh energy cosmic rays (UHECR) directionally correlated with the latest astrophysical neutrino tracks observed at IceCube, which are taken as point sources. In order to calculate these arrival directions we have considered contributions to the cosmic rays deflections originated by the galactic and the extragalactic magnetic field, and a UHECR composition compatible with the current expectations. We have used the Jansson-Farrar JF12 model for the Galactic magnetic field and an extragalactic magnetic field strength of 1nG and coherence length of 1Mpc. We observe that the regions outside of the Galactic plane are more strongly correlated with the neutrino tracks than those adjacent to or in it, with the former regions being good candidates to search for excesses, or anisotropies, in the UHECR flux. Additionally, we have focused, as an example, on the region of 150 EeV UHECR arrival directions correlated with the IceCube event 37 located at $(l,b)=(-137.1^\circ,65.8^\circ)$ in the Northern Hemisphere, far away from the Galactic plane, obtaining an angular size $\sim 5^\circ$, being $\sim 3^\circ$ for 200 EeV, and $\sim 8^\circ$ for 120 EeV. The results presented in this paper represent a useful UHECR excess search Sky map guide.

astro-ph.HE↗

arXiv2020

Revisiting quantum decoherence for neutrino oscillations in constant matter density

We re-examine the matter neutrino oscillation probabilities considering the decoherence phenomenon as a sub-leading effect. In this paper we point out the relevance of having the correct interpretation of the decoherence matrix in the different quantum bases, within the framework of neutrino oscillation probabilities in matter. Based on this treatment we develop an analytical formula for matter neutrino oscillation probabilities for three generations, with a range of application up to the decoherence parameter $Γ\sim 10^{-23}$ GeV. We observe that, due to decoherence, the amplitudes of the neutrino/antineutrino oscillation probabilities increase in an energy independent way. We also find that decoherence can reduce the absolute value of the CP asymmetry, relative to its value at the pure oscillation case. As a side effect we have found a degeneracy between the decoherence parameter $Γ$ and the CP violation phase $δ$.

hep-ph↗

arXiv2020

Effects of the Violation of the Equivalence Principle at DUNE

A number of different effects of the violation of the Equivalence Principle (VEP), taken as sub-leading mechanism of neutrino flavor oscillation, are examined within the framework of the DUNE experiment. We study the possibility of obtaining a misleading neutrino oscillation parameter region caused by our unawareness of VEP. Additionally, we evaluate the impact on the measurement of CP violation and the distinction of neutrino mass hierarchy at DUNE. Besides, limits on VEP for a wide variety of textures of the matrix that connects neutrino gravity eigenstates to flavor eigenstates are imposed. An extra-task of our study is to set limits on Hamiltonian added terms considering different energy dependencies ($E^n$, with $n=0,1,2,3$) that can be associated to the usual Lorentz violating terms defined in the Standard Model Extension Hamiltonian. In order to understand our results, approximated analytical three neutrino oscillation probability formulae are derived.

hep-ph↗

arXiv2019

Measurement of $ν_μ$ charged-current single $π^{0}$ production on hydrocarbon in the few-GeV region using MINERvA

The semi-exclusive channel $ν_μ+\textrm{CH}\rightarrowμ^{-}π^{0}+\textrm{nucleon(s)}$ is analyzed using MINERvA exposed to the low-energy NuMI $ν_μ$ beam with spectral peak at $E_ν \simeq 3$ GeV. Differential cross sections for muon momentum and production angle, $π^{0}$ kinetic energy and production angle, and for squared four-momentum transfer are reported, and the cross section $σ(E_ν)$ is obtained over the range 1.5 GeV $\leq E_ν <$ 20 GeV. Results are compared to GENIE and NuWro predictions and to published MINERvA cross sections for $ν_μ\textrm{-CC}(π^{+})$ and $\barν_μ\textrm{-CC}(π^{0})$. Disagreements between data and simulation are observed at very low and relatively high values for muon angle and for $Q^2$ that may reflect shortfalls in modeling of interactions on carbon. For $π^{0}$ kinematic distributions however, the data are consistent with the simulation and provide support for generator treatments of pion intranuclear scattering. Using signal-event subsamples that have reconstructed protons as well as $π^{0}$ mesons, the $pπ^{0}$ invariant mass distribution is obtained, and the decay polar and azimuthal angle distributions in the rest frame of the $pπ^{0}$ system are measured in the region of $Δ(1232)^+$ production, $W < 1.4$ GeV.

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