arXiv subjects

J. Felix

Publications and source records attributed to J. Felix.

At least 73 records · Page 4Linked to original sources

arXiv2015

Charged Pion Production in $ν_μ$ Interactions on Hydrocarbon at $\langle E_ν\rangle$= 4.0 GeV

Charged pion production via charged current $ν_μ$ interactions on plastic (CH) is studied using the MINERvA detector exposed to the NuMI wideband neutrino beam at Fermilab. Events with hadronic invariant mass W $<$ 1.4 GeV are selected to isolate single pion production, which is expected to occur primarily through the $Δ(1232)$ resonance. Cross sections as functions of pion production angle and kinetic energy are reported and compared to predictions from different theoretical calculations and generator-based models, for neutrinos ranging in energy from 1.5 GeV to 10 GeV. The data are best described by calculations which include significant contributions from pion intranuclear rescattering. These measurements constrain the primary interaction rate and the role of final state interactions in pion production, both of which need to be well understood by neutrino oscillation experiments.

hep-ex↗

arXiv2015

MINERvA neutrino detector response measured with test beam data

The MINERvA collaboration operated a scaled-down replica of the solid scintillator tracking and sampling calorimeter regions of the MINERvA detector in a hadron test beam at the Fermilab Test Beam Facility. This article reports measurements with samples of protons, pions, and electrons from 0.35 to 2.0 GeV/c momentum. The calorimetric response to protons, pions, and electrons are obtained from these data. A measurement of the parameter in Birks' law and an estimate of the tracking efficiency are extracted from the proton sample. Overall the data are well described by a Geant4-based Monte Carlo simulation of the detector and particle interactions with agreements better than 4%, though some features of the data are not precisely modeled. These measurements are used to tune the MINERvA detector simulation and evaluate systematic uncertainties in support of the MINERvA neutrino cross section measurement program.

physics.ins-det↗

arXiv2015

Measurement of muon plus proton final states in $ν_μ$ Interactions on Hydrocarbon at $\langle$$E_ν$$\rangle$ = 4.2 GeV

A study of charged-current muon neutrino scattering on hydrocarbon in which the final state includes a muon and a proton and no pions is presented. Although this signature has the topology of neutrino quasielastic scattering from neutrons, the event sample contains contributions from both quasielastic and inelastic processes where pions are absorbed in the nucleus. The analysis accepts events with muon production angles up to 70$^{\circ}$ and proton kinetic energies greater than 110 MeV. The extracted cross section, when based completely on hadronic kinematics, is well-described by a simple relativistic Fermi gas nuclear model including the neutrino event generator modeling for inelastic processes and particle transportation through the nucleus. This is in contrast to the quasielastic cross section based on muon kinematics, which is best described by an extended model that incorporates multi-nucleon correlations. This measurement guides the formulation of a complete description of neutrino-nucleus interactions that encompasses the hadronic as well as the leptonic aspects of this process.

hep-ex↗

arXiv2015

Measurement of Ratios of $ν_μ$ Charged-Current Cross Sections on C, Fe, and Pb to CH at Neutrino Energies 2-20 GeV

We present measurements of $ν_μ$ charged-current cross section ratios on carbon, iron, and lead relative to a scintillator (CH) using the fine-grained MINERvA detector exposed to the NuMI neutrino beam at Fermilab. The measurements utilize events of energies $2 =8~GeV$, which have a reconstructed $μ^{-}$ scattering angle less than $17^\circ$ to extract ratios of inclusive total cross sections as a function of neutrino energy $E_ν$ and flux-integrated differential cross sections with respect to the Bjorken scaling variable $x$. These results provide the first high-statistics direct measurements of nuclear effects in neutrino scattering using different targets in the same neutrino beam. Measured cross section ratios exhibit a relative depletion at low $x$ and enhancement at large $x$. Both become more pronounced as the nucleon number of the target nucleus increases. The data are not reproduced by GENIE, a conventional neutrino-nucleus scattering simulation, or by the alternative models for the nuclear dependence of inelastic scattering that are considered.

hep-ex↗

arXiv2014

Measurement of Coherent Production of $π^\pm$ in Neutrino and Anti-Neutrino Beams on Carbon from $E_ν$ of $1.5$ to $20$ GeV

Neutrino-induced coherent charged pion production on nuclei, $\stackrel{(-)}ν_μA\toμ^\pmπ^\mp A$ is a rare, inelastic interaction in which a small squared four-momentum $| t|$ is transferred to the recoil nucleus leaving it intact in the reaction. In the scintillator tracker of MINERvA, we remove events with evidence of particles from nuclear breakup and reconstruct $| t|$ from the final state pion and muon. We select low $| t|$ events to isolate a sample rich in coherent candidates. By selecting low $| t|$ events we produce a model-independent measurement of the differential cross section for coherent scattering of neutrinos and anti-neutrinos on carbon. We find poor agreement with the predicted kinematics in neutrino generators used by current oscillation experiments.

hep-ex↗

arXiv2014

Measurement of Muon Antineutrino Quasi-Elastic Scattering on a Hydrocarbon Target at E_ν ~ 3.5 GeV

We have isolated muon anti-neutrino charged-current quasi-elastic interactions occurring in the segmented scintillator tracking region of the MINERvA detector running in the NuMI neutrino beam at Fermilab. We measure the flux-averaged differential cross-section, dσ/dQ^2, and compare to several theoretical models of quasi-elastic scattering. Good agreement is obtained with a model where the nucleon axial mass, M_A, is set to 0.99 GeV/c^2 but the nucleon vector form factors are modified to account for the observed enhancement, relative to the free nucleon case, of the cross-section for the exchange of transversely polarized photons in electron-nucleus scattering. Our data at higher Q^2 favor this interpretation over an alternative in which the axial mass is increased.

hep-ex↗

arXiv2014

Measurement of Muon Neutrino Quasi-Elastic Scattering on a Hydrocarbon Target at E_ν ~ 3.5 GeV

We report a study of muon neutrino charged-current quasi-elastic events in the segmented scintillator inner tracker of the MINERvA experiment running in the NuMI neutrino beam at Fermilab. The events were selected by requiring a μ^- and low calorimetric recoil energy separated from the interaction vertex. We measure the flux-averaged differential cross-section, dσ/dQ^2, and study the low energy particle content of the final state. Deviations are found between the measured dσ/dQ^2 and the expectations of a model of independent nucleons in a relativistic Fermi gas. We also observe an excess of energy near the vertex consistent with multiple protons in the final state.

hep-ex↗

arXiv2013

Design, Calibration, and Performance of the MINERvA Detector

The MINERvA experiment is designed to perform precision studies of neutrino-nucleus scattering using $ν_μ$ and ${\barν}_μ$ neutrinos incident at 1-20 GeV in the NuMI beam at Fermilab. This article presents a detailed description of the \minerva detector and describes the {\em ex situ} and {\em in situ} techniques employed to characterize the detector and monitor its performance. The detector is comprised of a finely-segmented scintillator-based inner tracking region surrounded by electromagnetic and hadronic sampling calorimetry. The upstream portion of the detector includes planes of graphite, iron and lead interleaved between tracking planes to facilitate the study of nuclear effects in neutrino interactions. Observations concerning the detector response over sustained periods of running are reported. The detector design and methods of operation have relevance to future neutrino experiments in which segmented scintillator tracking is utilized.

physics.ins-det↗

arXiv2012

The MINER$ν$A Data Acquisition System and Infrastructure

MINER$ν$A (Main INjector ExpeRiment $ν$-A) is a new few-GeV neutrino cross section experiment that began taking data in the FNAL NuMI (Fermi National Accelerator Laboratory Neutrinos at the Main Injector) beam-line in March of 2010. MINER$ν$A employs a fine-grained scintillator detector capable of complete kinematic characterization of neutrino interactions. This paper describes the MINER$ν$A data acquisition system (DAQ) including the read-out electronics, software, and computing architecture.

physics.ins-det↗

arXiv2012

Demonstration of Communication using Neutrinos

Beams of neutrinos have been proposed as a vehicle for communications under unusual circumstances, such as direct point-to-point global communication, communication with submarines, secure communications and interstellar communication. We report on the performance of a low-rate communications link established using the NuMI beam line and the MINERvA detector at Fermilab. The link achieved a decoded data rate of 0.1 bits/sec with a bit error rate of 1% over a distance of 1.035 km, including 240 m of earth.

hep-ex↗

arXiv2012

Arachne - A web-based event viewer for MINERvA

Neutrino interaction events in the MINERvA detector are visually represented with a web-based tool called Arachne. Data are retrieved from a central server via AJAX, and client-side JavaScript draws images into the user's browser window using the draft HTML 5 standard. These technologies allow neutrino interactions to be viewed by anyone with a web browser, allowing for easy hand-scanning of particle interactions. Arachne has been used in MINERvA to evaluate neutrino data in a prototype detector, to tune reconstruction algorithms, and for public outreach and education.

hep-ex↗

arXiv2010

Study of the rare hyperon decay Omega \to Xi π^+ π^-

We report a new measurement of the decay Ω^- \to Ξ^- π^+ π^- with 76 events and a first observation of the decay Ω^+ \to Ξ^+ π^+ π^- with 24 events, yielding a combined branching ratio (3.74 ^{+0.67}_{-0.56}) \times 10^{-4}. This represents a factor 25 increase in statistics over the best previous measurement. No evidence is seen for CP violation, with B(Ω^- \to Ξ^- π^+ π^-)=4.04^{+0.83}_{-0.71} \times 10^{-4} and B(Ω^+ \to Ξ^+ π^+ π^-)=3.15^{+1.12}_{-0.89} \times 10^{-4}. Contrary to theoretical expectation, we see little evidence for the decays Ω^- \to Ξ_{1530}^{*0} π^- and Ω^+ \to Ξ_{1530}^{*0} π^+ and place a 90% C.L. upper limit on the combined branching ratio B(Ω^-(Ω^+) \to Ξ^{*0}_{1530}(Ξ^{*0}_{1530}) π^\mp)<7.0 \times 10^{-5}.

hep-ex↗

arXiv2005

Search for Exotic Baryons in 800 GeV pp (rtarrow) pXiPiX

We report the results of a high-statistics, sensitive search for narrow baryon resonances decaying to $Ξ^-π^-$, $Ξ^-π^+$, $\barΞ^+π^-$, and $\barΞ^+π^+$. The only resonances observed are the well known $Ξ^0(1530)$ and $\bar{Ξ^0}(1530)$. No evidence is found for a state near 1862 MeV, previously reported by NA49\cite{NA49}. At the 95% confidence level, we find the upper limit for the production of a Gaussian enhancement with $σ=7.6$ MeV in the $Ξ^-π^-$ effective mass spectrum to be 0.3% of the number of observed $Ξ^0(1530)\toΞ^-π^+$. We find similarly restrictive upper limits for an enhancement at 1862 MeV in the $Ξ^-π^+$, $\barΞ^+π^-$, and $\barΞ^+π^+$ mass spectra.

hep-ex↗

arXiv2005

Search for the Lepton-Number-Violating Decay $Ξ^- \to p μ^- μ^-$

A sensitive search for the lepton-number-violating decay $Ξ^-\to p μ^-μ^-$ has been performed using a sample of $\sim10^9$ $Ξ^-$ hyperons produced in 800 GeV/$c$ $p$-Cu collisions. We obtain $\mathcal{B}(Ξ^-\to p μ^-μ^-)< 4.0\times 10^{-8}$ at 90% confidence, improving on the best previous limit by four orders of magnitude.

hep-ex↗

arXiv2005

Observation of Parity Violation in the Omega-minus -> Lambda + K-minus Decay

The alpha decay parameter in the process Omega-minus -> Lambda + K-minus has been measured from a sample of 4.50 million unpolarized Omega-minus decays recorded by the HyperCP (E871) experiment at Fermilab and found to be [1.78 +/- 0.19(stat) +/- 0.16(syst)]{\times}10^{-2}. This is the first unambiguous evidence for a nonzero alpha decay parameter, and hence parity violation, in the Omega-minus -> Lambda + K-minus decay.

hep-ex↗

arXiv2005

delta S = 2 nonleptonic hyperon decays

A sensitive search for the rare decays Ω^- \to Λπ^- and Ξ^0 \to p π^- has been performed using data from the 1997 run of the HyperCP (Fermilab E871) experiment. Limits on other such processes do not exclude the possibility of observable rates for |ΔS| = 2 nonleptonic hyperon decays, provided the decays occur through parity-odd operators. We obtain the branching-fraction limits B(Ω^- \to Λπ^-)< 2.9 x 10^{-6} and B(Ξ^0 \to p π^-)< 8.2 x 10^{-6}, both at 90% confidence level.

hep-ex↗

arXiv2005

Measurement of the Alpha Asymmetry Parameter for the Omega- to Lambda K- Decay

We have measured the alpha parameter of the Omega- to Lambda K- decay using data collected with the HyperCP spectrometer during the 1997 fixed-target run at Fermilab. Analyzing a sample of 0.96 million Omega- to Lambda K^-, Lambda to p pi- decays, we obtain alpha_Omega*alpha_Lambda = [1.33+/-0.33(stat)+/-0.52(syst)] x 10^{-2}. With the accepted value of alpha_Lambda, alpha_Omega is found to be [2.07+/-0.51(stat)+/-0.81(syst)] x 10^{-2}.

hep-ex↗

arXiv2005

Evidence for the Decay Sigma+ -> p mu+ mu-

We report the first evidence for the decay Sigma+ -> p mu+ mu- from data taken by the HyperCP experiment(E871) at Fermilab. Based on three observed events, the branching ratio is B(Sigma+ -> p,mu+,mu-) = [8.6 +6.6,-5.4(stat) +/-5.5(syst)] x 10**-8. The narrow range of dimuon masses may indicate that the decay proceeds via a neutral intermediate state, Sigma+ -> p P0, P0 -> mu+ mu-, with a P0 mass of 214.3 +/- 0.5 MeV/c**2 and branching ratio B(Sigma+ -> p P0; P0 -> mu+ mu-) = [3.1 +2.4,-1.(stat) +/-1.5(syst)] x 10**-8.

hep-ex↗