IF - Instituto de Física

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http://200.137.215.59//handle/ri/841

O IF - Instituto de Física, da Universidade Federal de Goiás, oferece Graduação em: Bacharelado em Física; Licenciatura em Física; Física Médica; e, Engenharia Física.

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Adjusting neutrino interaction models and evaluating uncertainties using NOvA near detector data
(2020) Acero Ortega, Mario A.; Adamson, P.; Agam, G.; Soplin, Leonidas Aliaga; Alion, T.; Allakhverdian, Vladimir; Anfimov, Nikolay; Antoshkin, A.; Asquith, Lily; Aurisano, Adam; Gomes, Ricardo Avelino
The two-detector design of the NOvA neutrino oscillation experiment, in which two functionally identical detectors are exposed to an intense neutrino beam, aids in canceling leading order effects of cross-section uncertain ties. However, limited knowledge of neutrino interaction cross sections still gives rise to some of the largest system atic uncertainties in current oscillation measurements. We show contemporary models of neutrino interactions to be discrepant with data from NOvA, consistent with discrep ancies seen in other experiments. Adjustments to neutrino interaction models in GENIE are presented, creating an effec tive model that improves agreement with our data. We also describe systematic uncertainties on these models, includ ing uncertainties on multi-nucleon interactions from a newly developed procedure using NOvA near detector data.
Constraints on large extra dimensions from the MINOS experiment
(2016) Adamson, P.; Anghel, I.; Aurisano, Adam; Barr, Giles; Bishai, Mary; Blake, A.; Bock, Gregory J.; Bogert, D.; Cao, S. V.; Carroll, T. J.; Gomes, Ricardo Avelino
We report new constraints on the size of large extra dimensions from data collected by the MINOS experiment between 2005 and 2012. Our analysis employs a model in which sterile neutrinos arise as Kaluza-Klein states in large extra dimensions and thus modify the neutrino oscillation probabilities due to mixing between active and sterile neutrino states. Using Fermilab’s Neutrinos at the Main Injector beam exposure of 10.56 × 1020 protons on target, we combine muon neutrino charged current and neutral current data sets from the Near and Far Detectors and observe no evidence for deviations from standard three-flavor neutrino oscillations. The ratios of reconstructed energy spectra in the two detectors constrain the size of large extra dimensions to be smaller than 0.45 μm at 90% C.L. in the limit of a vanishing lightest active neutrino mass. Stronger limits are obtained for nonvanishing masses.
Extended search for supernovalike neutrinos in NOvA coincident with LIGO/Virgo detections
(2021) Acero Ortega, Mario A.; Adamson, P.; Soplin, Leonidas Aliaga; Anfimov, Nikolay; Antoshkin, A.; Arrieta Diaz, Enrique; Asquith, Lily; Aurisano, Adam; Back, A.; Backhouse, C.; Gomes, Ricardo Avelino
A search is performed for supernovalike neutrino interactions coincident with 76 gravitational wave events detected by the LIGO/Virgo Collaboration. For 40 of these events, full readout of the time around the gravitational wave is available from the NOvA Far Detector. For these events, we set limits on the fluence of the sum of all neutrino flavors of F < 7ð4Þ × 1010 cm−2 at 90% C.L. assuming energy and time distributions corresponding to the Garching supernova models with masses 9.6ð27Þ M⊙. Under the hypothesis that any given gravitational wave event was caused by a supernova, this corresponds to a distance of r > 29ð50Þ kpc at 90% C.L. Weaker limits are set for other gravitational wave events with partial Far Detector data and/or Near Detector data.
First measurement of electron neutrino appearance in NOvA
(2016) Adamson, P.; Ader, Christine; Andrews, Michael; Anfimov, Nikolay; Anghel, I.; Arms, K.; Arrieta Diaz, Enrique; Aurisano, Adam; Ayres, D. S.; Backhouse, C.; Gomes, Ricardo Avelino
We report results from the first search for νμ → νe transitions by the NOvA experiment. In an exposure equivalent to 2.74 × 1020 protons on target in the upgraded NuMI beam at Fermilab, we observe 6 events in the Far Detector, compared to a background expectation of 0.99 0.11ðsystÞ events based on the Near Detector measurement. A secondary analysis observes 11 events with a background of 1.07 0.14ðsystÞ. The 3.3σ excess of events observed in the primary analysis disfavors 0.1π < δCP < 0.5π in the inverted mass hierarchy at the 90% C.L.
First measurement of neutrino oscillation parameters using neutrinos and antineutrinos by NOvA
(2019) Acero Ortega, Mario A.; Adamson, P.; Soplin, Leonidas Aliaga; Alion, T.; Allakhverdian, Vladimir; Altakarli, Sef; Anfimov, Nikolay; Antoshkin, A.; Aurisano, Adam; Back, A.; Gomes, Ricardo Avelino
The NOvA experiment has seen a 4.4σ signal of ¯νe appearance in a 2 GeV ¯νμ beam at a distance of 810 km. Using 12.33 × 1020 protons on target delivered to the Fermilab NuMI neutrino beamline, the experiment recorded 27 ¯νμ → ¯νe candidates with a background of 10.3 and 102 ¯νμ → ¯νμ candidates. This new antineutrino data are combined with neutrino data to measure the parameters jΔm2 32j ¼ 2.48þ0.11 −0.06 × 10−3 eV2=c4 and sin2 θ23 in the ranges from (0.53–0.60) and (0.45–0.48) in the normal neutrino mass hierarchy. The data exclude most values near δCP ¼ π=2 for the inverted mass hierarchy by more than 3σ and favor the normal neutrino mass hierarchy by 1.9σ and θ23 values in the upper octant by 1.6σ.
Improved constraints on sterile neutrino mixing from disappearance searches in the MINOS+Daya Bay, and Bugey-3 experiments
(2020) Adamson, P.; An, F. P.; Anghel, I.; Aurisano, Adam; Balantekin, A. Baha; Band, H. R.; Barr, Giles; Bishai, Mary; Blake, A.; Blyth, S.; Gomes, Ricardo Avelino
Searches for electron antineutrino, muon neutrino, and muon antineutrino disappearance driven by sterile neutrino mixing have been carried out by the Daya Bay and MINOSþ collaborations. This Letter presents the combined results of these searches, along with exclusion results from the Bugey-3 reactor experiment, framed in a minimally extended four-neutrino scenario. Significantly improved constraints on the θμe mixing angle are derived that constitute the most constraining limits to date over five orders of magnitude in the mass-squared splitting Δm2 41, excluding the 90% C.L. sterile-neutrino parameter space allowed by the LSND and MiniBooNE observations at 90% CLs for Δm2 41 < 13 eV2 . Furthermore, the LSND and MiniBooNE 99% C.L. allowed regions are excluded at 99% CLs for Δm2 41 < 1.6 eV2.
Improved measurement of neutrino oscillation parameters by the NOvA experiment
(2022) Acero Ortega, Mario A.; Soplin‬, ‪Leonidas Aliaga; Adamson, P.; Anfimov, Nikolay; Antoshkin, A.; Arrieta Diaz, Enrique; Asquith, Lily; Aurisano, Adam; Back, A.; Backhouse, C.; Gomes, Ricardo Avelino
We present new νμ → νe, νμ → νμ, ¯νμ → ¯νe, and ¯νμ → ¯νμ oscillation measurements by the NOvA experiment, with a 50% increase in neutrino-mode beam exposure over the previously reported results. The additional data, combined with previously published neutrino and antineutrino data, are all analyzed using improved techniques and simulations. A joint fit to the νe, νμ, ¯νe, and ¯νμ candidate samples within the 3-flavor neutrino oscillation framework continues to yield a best-fit point in the normal mass ordering and the upper octant of the θ23 mixing angle, with Δm2 32 ¼ ð2.41 0.07Þ × 10−3 eV2 and sin2 θ23 ¼ 0.57þ0.03 −0.04 . The data disfavor combinations of oscillation parameters that give rise to a large asymmetry in the rates of νe and ¯νe appearance. This includes values of the charge parity symmetry (CP) violating phase in the vicinity of δCP ¼ π=2 which are excluded by > 3σ for the inverted mass ordering, and values around δCP ¼ 3π=2 in the normal ordering which are disfavored at 2σ confidence.
Limits on active to sterile neutrino oscillations from disappearance searches in the MINOS, daya bay, and bugey-3 experiments
(2016) Adamson, P.; An, F. P.; Anghel, I.; Aurisano, Adam; Balantekin, A. Baha; Band, H. R.; Barr, Giles; Bishai, Mary; Blake, A.; Blyth, S.; Gomes, Ricardo Avelino
Searches for a light sterile neutrino have been performed independently by the MINOS and the Daya Bay experiments using the muon (anti)neutrino and electron antineutrino disappearance channels, respectively. In this Letter, results from both experiments are combined with those from the Bugey-3 reactor neutrino experiment to constrain oscillations into light sterile neutrinos. The three experiments are sensitive to complementary regions of parameter space, enabling the combined analysis to probe regions allowed by the Liquid Scintillator Neutrino Detector (LSND) and MiniBooNE experiments in a minimally extended four-neutrino flavor framework. Stringent limits on sin2 2θμe are set over 6 orders of magnitude in the sterile mass-squared splitting Δm2 41. The sterile-neutrino mixing phase space allowed by the LSND and MiniBooNE experiments is excluded for Δm2 41 < 0.8 eV2 at 95% CLs.
Measurement of neutrino-induced neutral-current coherent π0 production in the NOvA near detector
(2020) Acero Ortega, Mario A.; Adamson, P.; Soplin, Leonidas Aliaga; Alion, T.; Allakhverdian, Vladimir; Anfimov, Nikolay; Antoshkin, A.; Diaz, Enrique Arrieta; Aurisano, Adam; Back, A.; Gomes, Ricardo Avelino
The cross section of neutrino-induced neutral-current coherent π0 production on a carbon-dominated target is measured in the NOvA near detector. This measurement uses a narrow-band neutrino beam with an average neutrino energy of 2.7 GeV, which is of interest to ongoing and future long-baseline neutrino oscillation experiments. The measured, flux-averaged cross section is σ ¼ 13.8 0.9ðstatÞ 2.3ðsystÞ × 10−40 cm2=nucleus, consistent with model prediction. This result is the most precise measure ment of neutral-current coherent π0 production in the few-GeV neutrino energy region.
Measurement of single π0 production by coherent neutral-current ν Fe interactions in the MINOS Near Detector
(2016) Adamson, P.; Anghel, I.; Aurisano, Adam; Barr, Giles; Bishai, Mary; Blake, A.; Bock, Gregory J.; Bogert, D.; Carroll, T. J.; Gomes, Ricardo Avelino
Forward single π0 production by coherent neutral-current interactions, νA → νAπ0, is investigated using a 2.8 × 1020 protons-on-target exposure of the MINOS Near Detector. For single-shower topologies, the event distribution in production angle exhibits a clear excess above the estimated background at very forward angles for visible energy in the range 1–8 GeV. Cross sections are obtained for the detector medium comprised of 80% iron and 20% carbon nuclei with hAi ¼ 48, the highest-hAi target used to date in the study of this coherent reaction. The total cross section for coherent neutral-current single π0 production initiated by the νμ flux of the NuMI low-energy beam with mean (mode) Eν of 4.9 GeV (3.0 GeV), is 77.6 5.0ðstatÞþ15.0 −16.8 ðsystÞ × 10−40 cm2 pernucleus. The results are in good agreement with predictions of the Berger-Sehgal model.
Measurement of the multiple-muon charge ratio in the MINOS Far Detector
(2016) Adamson, P.; Anghel, I.; Aurisano, Adam; Barr, Giles; Bishai, Mary; Blake, A.; Bock, Gregory J.; Bogert, D.; Cao, S. V.; Carroll, T. J.; Gomes, Ricardo Avelino
The charge ratio, Rμ ¼ Nμþ =Nμ− , for cosmogenic multiple-muon events observed at an underground depth of 2070 mwe has been measured using the magnetized MINOS Far Detector. The multiple-muon events, recorded nearly continuously from August 2003 until April 2012, comprise two independent data sets imaged with opposite magnetic field polarities, the comparison of which allows the systematic uncertainties of the measurement to be minimized. The multiple-muon charge ratio is determined to be Rμ ¼ 1.104 0.006ðstatÞþ0.009 −0.010 ðsystÞ. This measurement complements previous determinations of single muon and multiple-muon charge ratios at underground sites and serves to constrain models of cosmic-ray interactions at TeV energies.
Measurement of the Neutrino Mixing Angle θ23 in NOvA
(2017) Adamson, P.; Soplin, Leonidas Aliaga; Ambrose, D.; Anfimov, Nikolay; Antoshkin, A.; Arrieta Diaz, Enrique; Augsten, Kamil; Aurisano, Adam; Backhouse, C.; Baird, M.; Gomes, Ricardo Avelino
This Letter reports new results on muon neutrino disappearance from NOvA, using a 14 kton detector equivalent exposure of 6.05 × 1020 protons on target from the NuMI beam at the Fermi National Accelerator Laboratory. The measurement probes the muon-tau symmetry hypothesis that requires maximal θ23 mixing (θ23 ¼ π=4). Assuming the normal mass hierarchy, we find Δm2 32 ¼ ð2.67 0.11Þ × 10−3 eV2 and sin2 θ23 at the two statistically degenerate values 0.404þ0.030 −0.022 and 0.624þ0.022 −0.030 , both at the 68% confidence level. Our data disfavor the maximal mixing scenario with 2.6σ significance.
New constraints on oscillation parameters from νe appearance and νμ disappearance in the NOvA experiment
(2018) Acero Ortega, Mario A.; Adamson, P.; Soplin, Leonidas Aliaga; Alion, T.; Allakhverdian, Vladimir; Anfimov, Nikolay; Antoshkin, A.; Arrieta Diaz, Enrique; Aurisano, Adam; Back, A.; Gomes, Ricardo Avelino
We present updated results from the NOvA experiment for νμ → νμ and νμ → νe oscillations from an exposure of 8.85 × 1020 protons on target, which represents an increase of 46% compared to our previous publication. The results utilize significant improvements in both the simulations and analysis of the data. A joint fit to the data for νμ disappearance and νe appearance gives the best-fit point as normal mass hierarchy, Δm2 32 ¼ 2.44 × 10−3 eV2=c4, sin2 θ23 ¼ 0.56, and δCP ¼ 1.21π. The 68.3% confidence intervals in the normal mass hierarchy are Δm2 32 ∈ ½2.37; 2.52 × 10−3 eV2=c4, sin2 θ23 ∈ ½0.43; 0.51 ∪ ½0.52; 0.60 , and δCP ∈ ½0; 0.12π ∪ ½0.91π; 2π . The inverted mass hierarchy is disfavored at the 95% confidence level for all choices of the other oscillation parameters.
New constraints on oscillation parameters from νe appearance and νμ disappearance in the NOvA experiment
(2018) Acero Ortega, Mario A.; Adamson, P.; Soplin, Leonidas Aliaga; Alion, T.; Allakhverdian, Vladimir; Anfimov, Nikolay; Antoshkin, A.; Arrieta Diaz, Enrique; Aurisano, Adam; Back, A.; Gomes, Ricardo Avelino
We present updated results from the NOvA experiment for νμ → νμ and νμ → νe oscillations from an exposure of 8.85 × 1020 protons on target, which represents an increase of 46% compared to our previous publication. The results utilize significant improvements in both the simulations and analysis of the data. A joint fit to the data for νμ disappearance and νe appearance gives the best-fit point as normal mass hierarchy, Δm2 32 ¼ 2.44 × 10−3 eV2=c4, sin2 θ23 ¼ 0.56, and δCP ¼ 1.21π. The 68.3% confidence intervals in the normal mass hierarchy are Δm2 32 ∈ ½2.37; 2.52 × 10−3 eV2=c4, sin2 θ23 ∈ ½0.43; 0.51 ∪ ½0.52; 0.60 , and δCP ∈ ½0; 0.12π ∪ ½0.91π; 2π . The inverted mass hierarchy is disfavored at the 95% confidence level for all choices of the other oscillation parameters.
Observation of seasonal variation of atmospheric multiple-muon events in the NOvA Near Detector
(2019) Acero Ortega, Mario A.; Adamson, P.; Soplin, Leonidas Aliaga; Alion, T.; Allakhverdian, Vladimir; Altakarli, Sef; Anfimov, Nikolay; Antoshkin, A.; Aurisano, Adam; Back, A.; Gomes, Ricardo Avelino
Using two years of data from the NOvA Near Detector at Fermilab, we report a seasonal variation of cosmic ray induced multiple-muon (Nμ ≥ 2) event rates which has an opposite phase to the seasonal variation in the atmospheric temperature. The strength of the seasonal multiple-muon variation is shown to increase as a function of the muon multiplicity. However, no significant dependence of the strength of the seasonal variation of the multiple-muon variation is seen as a function of the muon zenith angle, or the spatial or angular separation between the correlated muons.
Precision constraints for three-flavor neutrino oscillations from the full and MINOS dataset
(2020) Adamson, P.; Anghel, I.; Aurisano, Adam; Barr, Giles; Blake, A.; Cao, S. V.; Carroll, T. J.; Castromonte Flores, Cesar Manuel; Chen, R.; Childress, S.; Gomes, Ricardo Avelino
We report the final measurement of the neutrino oscillation parameters Δm2 32 and sin2 θ23 using all data from the MINOS and MINOSþ experiments. These data were collected using a total exposure of 23.76 × 1020 protons on target producing νμ and ¯νμ beams and 60.75 kt yr exposure to atmospheric neutrinos. The measurement of the disappearance of νμ and the appearance of νe events between the Near and Far detectors yields jΔm2 32j ¼ 2.40þ0.08 −0.09 ð2.45þ0.07 −0.08 Þ × 10−3 eV2 and sin2 θ23 ¼ 0.43þ0.20 −0.04 ð0.42þ0.07 −0.03 Þ at 68% C.L. for normal (inverted) hierarchy.
Search for active-sterile antineutrino mixing using neutral-current interactions with the NOvA experiment
(2021) Acero Ortega, Mario A.; Adamson, P.; Asquith, L.; Anfimov, Nikolay; Antoshkin, A.; Arrieta Diaz, Enrique; Asquith, Lily; Aurisano, Adam; Back, A.; Backhouse, C.; Gomes, Ricardo Avelino
This Letter reports results from the first long-baseline search for sterile antineutrinos mixing in an accelerator-based antineutrino-dominated beam. The rate of neutral-current interactions in the two NOvA detectors, at distances of 1 and 810 km from the beam source, is analyzed using an exposure of 12.51 × 1020 protons-on-target from the NuMI beam at Fermilab running in antineutrino mode. A total of 121 of neutral-current candidates are observed at the far detector, compared to a prediction of 122 11ðstat:Þ 15ðsyst:Þ assuming mixing only between three active flavors. No evidence for ¯νμ → ¯νs oscillation is observed. Interpreting this result within a 3 þ 1 model, constraints are placed on the mixing angles θ24 < 25° and θ34 < 32° at the 90% C.L. for 0.05 eV2 ≤ Δm2 41 ≤ 0.5 eV2, the range of mass splittings that produces no significant oscillations at the near detector. These are the first 3 þ 1 confidence limits set using long-baseline accelerator antineutrinos.
Search for active-sterile neutrino mixing using neutral-current interactions in NOvA
(2017) Adamson, P.; Soplin, Leonidas Aliaga; Ambrose, D.; Anfimov, Nikolay; Antoshkin, A.; Arrieta Diaz, Enrique; Augsten, Kamil; Aurisano, Adam; Backhouse, C.; Baird, M.; Gomes, Ricardo Avelino
We report results from the first search for sterile neutrinos mixing with active neutrinos through a reduction in the rate of neutral-current interactions over a baseline of 810 km between the NOvA detectors. Analyzing a 14-kton detector equivalent exposure of 6.05 × 1020 protons-on-target in the NuMI beam at Fermilab, we observe 95 neutral-current candidates at the Far Detector compared with 83.5 9.7ðstatÞ 9.4ðsystÞ events predicted assuming mixing only occurs between active neutrino species. No evidence for νμ → νs transitions is found. Interpreting these results within a 3 þ 1 model, we place constraints on the mixing angles θ24 < 20.8° and θ34 < 31.2° at the 90% C.L. for 0.05 eV2 ≤ Δm2 41 ≤ 0.5 eV2, the range of mass splittings that produce no significant oscillations over the Near Detector baseline.
Search for flavor-changing nonstandard neutrino interactions using νe appearance in MINOS
(2017) Adamson, P.; Anghel, I.; Aurisano, Adam; Barr, Giles; Bishai, Mary; Blake, A.; Bock, Gregory J.; Bogert, D.; Cao, S. V.; Carroll, T. J.; Gomes, Ricardo Avelino
We report new constraints on flavor-changing nonstandard neutrino interactions from the MINOS long baseline experiment using νe and ¯νe appearance candidate events from predominantly νμ and ¯νμ beams. We used a statistical selection algorithm to separate νe candidates from background events, enabling an analysis of the combined MINOS neutrino and antineutrino data. We observe no deviations from standard neutrino mixing, and thus place constraints on the nonstandard interaction matter effect, jεeτj, and phase, ðδCP þ δeτÞ, using a 30-bin likelihood fit.
Search for multimessenger signals in NOvA coincident with LIGO/Virgo detections
(2020) Acero Ortega, Mario A.; Adamson, P.; Soplin, Leonidas Aliaga; Alion, T.; Allakhverdian, Vladimir; Anfimov, Nikolay; Antoshkin, A.; Asquith, Lily; Aurisano, Adam; Avelino, Ricardo Gomes
Using the NOvA neutrino detectors, a broad search has been performed for any signal coincident with 28 gravitational wave events detected by the LIGO/Virgo Collaboration between September 2015 and July 2019. For all of these events, NOvA is sensitive to possible arrival of neutrinos and cosmic rays of GeV and higher energies. For five (seven) events in the NOvA Far (Near) Detector, timely public alerts from the LIGO/Virgo Collaboration allowed recording of MeV-scale events. No signal candidates were found.

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