Quasi-elastic Interactions Research Articles

Impact of phase on collision between vortex solitons in three-dimensional cubic-quintic complex Ginzburg-Landau equation.

We present a systematic analysis for three generic collisional outcomes between stable dissipative vortices with intrinsic vorticity S = 0, 1, or 2 upon variation of relative phase in the three-dimensional (3D) cubic-quintic complex Ginzburg-Landau equation. The first type outcome is merger of the vortices into a single one, of which velocity can be effectively controlled by relative phase. With the increase of the collision momentum, the following is creation of an extra vortex, and its velocity also increases with growth of relative phase. However, at largest collision momentum, the variety of relative phase cannot change the third type collisional outcomes, quasielastic interaction. In addition, the dynamic range of the outcome of creating an extra vortex decreases with the reduction of cubic-gain. The above features have potential applications in optical switching and logic gates based on interaction of optical solitons.

Detection of back-to-back proton pairs in charged-current neutrino interactions with the ArgoNeuT detector in the NuMI low energy beam line

Short range nucleon-nucleon correlations in nuclei (NN SRC) carry important information on nuclear structure and dynamics. NN SRC have been extensively probed through two-nucleon knock- out reactions in both pion and electron scattering experiments. We report here on the detection of two-nucleon knock-out events from neutrino interactions and discuss their topological features as possibly involving NN SRC content in the target argon nuclei. The ArgoNeuT detector in the Main Injector neutrino beam at Fermilab has recorded a sample of 30 fully reconstructed charged current events where the leading muon is accompanied by a pair of protons at the interaction vertex, 19 of which have both protons above the Fermi momentum of the Ar nucleus. Out of these 19 events, four are found with the two protons in a strictly back-to-back high momenta configuration directly observed in the final state and can be associated to nucleon Resonance pionless mechanisms involving a pre-existing short range correlated np pair in the nucleus. Another fraction (four events) of the remaining 15 events have a reconstructed back-to-back configuration of a np pair in the initial state, a signature compatible with one-body Quasi Elastic interaction on a neutron in a SRC pair. The detection of these two subsamples of the collected (mu- + 2p) events suggests that mechanisms directly involving nucleon-nucleon SRC pairs in the nucleus are active and can be efficiently explored in neutrino-argon interactions with the LAr TPC technology.

Charged current quasi-elastic cross-section measurements in MiniBooNE

The neutrino-induced charged-current quasi-elastic (CCQE, νl + n → l- + p or [Formula: see text]) interaction is the most abundant interaction around 1 GeV, and it is the most fundamental channel to study neutrino oscillations. Recently, MiniBooNE published both muon neutrino1 and muon anti-neutrino2 double differential cross-sections on carbon. In this review, we describe the details of these analyses and include some historical remarks.

Neutrino-nucleus quasi-elastic and 2p2h interactions up to 10 GeV

We extend to 10 GeV results from a microscopic calculation of charged-current neutrino-nucleus reactions that do not produce a pion in the final state. For the class of events coming from neutrino interactions with two nucleons producing two holes (2p2h), limiting the calculation to three-momentum transfers less than 1.2 GeV produces a two dimensional distribution in momentum and energy transfer that is roughly constant as a function of energy. The cross section for 2p2h interactions scales with the number of nucleons for isoscalar nuclei, similar to the quasi-elastic (QE) cross section. When limited to momentum transfers below 1.2 GeV, the cross section is 26% of the QE cross section at 3 GeV, but 14% if we neglect a Delta1232 resonance absorption component. The same quantities are 33% and 17% for anti-neutrinos. For the quasi-elastic interactions, the full nuclear model with long range correlations produces an even larger, but approximately constant distortion of the shape of the four-momentum transfer at all energies above 2 GeV. The 2p2h enhancement and long-range correlation distortions to the cross section for these interactions is significant enough they should be observable in precision experiments to measure neutrino oscillations and neutrino interactions at these energies, but also balance out and produce less total distortion than each effect does individually.

Measurement of Muon Antineutrino Quasielastic Scattering on a Hydrocarbon Target atEν∼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, d{\sigma}/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.

Two particle-two hole excitations in charged current quasielastic neutrino-nucleus interactions

We review the theoretical status of the models including the multinucleon emission channel in the calculation of quasielastic neutrino cross sections at MiniBooNE kinematics.

Neutrino detection in the ArgoNeuT LAr TPC

ArgoNeuT, a Liquid Argon Time Projection Chamber (LAr-TPC), has collected thousands of neutrino and anti-neutrino events between 0.1 and 10 GeV in the NuMI beamline at Fermilab (FNAL). Among other issues, the experiment will measure the cross section of the neutrino and anti-neutrino Charged Current Quasi-Elastic (CC QE) interaction on Ar target and analyze the vertex activity associated with such events. ArgoNeuT data analysis and FSI studies in progress are described and first measurements of inclusive muon neutrino Charged Current differential cross sections on Argon are reported.

Collisions between Solitons Modulated by Gain/Loss and Phase in the Complex Ginzburg—Landau Equation

We present a systematic analysis for influence of phase φ on collisions of dissipative solitons, using the cubic-quintic complex Ginzburg—Landau equation in the absence of viscosity. Four generic outcomes are revealed upon the variation of gain/loss: merger of the two solitons into a single one; quasi-elastic interactions; creation of an extra soliton; and dissipation of the two solitons for in-phase. The velocities of the merger-soliton and the extra soliton can be effectively controlled by relative phase. The above features have potential applications in optical switching and logic gates based on interaction of optical solitons.

Differences in quasielastic cross sections of muon and electron neutrinos

Accelerator neutrino oscillation experiments seek to make precision measurements of the neutrino flavor oscillations muon (anti)neutrino to electron (anti)neutrino in order to determine the mass hierarchy of neutrinos and to search for CP violation in neutrino oscillations. These experiments are currently performed with beams of muon neutrinos at energies near 1 GeV where the charged-current quasi-elastic interactions nu+n\rightarrow(l^-)+p and anti-nu+p\rightarrow(l^+)+n dominate the signal reactions. We examine the difference between the quasi-elastic cross-sections for muon and electron neutrinos and anti-neutrinos and estimate the uncertainties on these differences.

K2K cross section results

This paper contains results from several cross section studies made using the near detectors in the K2K neutrino beam. These include an estimate of neutral current single π 0 production, an upper limit on the cross section for charged current coherent π + production, and an analysis of the axial vector form factor for quasi-elastic interactions.

Phase controlling of collisions between solitons in the two-dimensional complex Ginzburg-Landau equation without viscosity

We present a systematic analysis of the outcome of soliton collisions upon variation of the relative phase φ of the solitons, in the two-dimensional cubic-quintic complex Ginzburg-Landau equation in the absence of viscosity. Three generic outcomes are identified: merger of the solitons into a single one, creation of an extra soliton, and quasielastic interaction. The velocities of the merger soliton and the extra soliton can be effectively controlled by φ. In addition, the range of the outcome of creating an extra soliton decreases to zero with the reduction of gain or the increasing of loss. The above features have potential applications in optical switching and logic gates based on interaction of optical solitons.

Measurement of the neutrino component of an antineutrino beam observed by a nonmagnetized detector

Two independent methods are employed to measure the neutrino flux of the anti-neutrino-mode beam observed by the MiniBooNE detector. The first method compares data to simulated event rates in a high purity $\numu$ induced charged-current single $\pip$ (CC1$\pip$) sample while the second exploits the difference between the angular distributions of muons created in $\numu$ and $\numub$ charged-current quasi-elastic (CCQE) interactions. The results from both analyses indicate the prediction of the neutrino flux component of the pre-dominately anti-neutrino beam is over-estimated - the CC1$\pip$ analysis indicates the predicted $\numu$ flux should be scaled by $0.76 \pm 0.11$, while the CCQE angular fit yields $0.65 \pm 0.23$. The energy spectrum of the flux prediction is checked by repeating the analyses in bins of reconstructed neutrino energy, and the results show that the spectral shape is well modeled. These analyses are a demonstration of techniques for measuring the neutrino contamination of anti-neutrino beams observed by future non-magnetized detectors.

ArgoNeuT and the Neutrino-Argon Charged Current Quasi-Elastic Cross Section

ArgoNeuT, a Liquid Argon Time Projection Chamber in the NuMI beamline at Fermilab, has recently collected thousands of neutrino and anti-neutrino events between 0.1 and 10 GeV. The experiment will, among other things, measure the cross section of the neutrino and anti-neutrino Charged Current Quasi-Elastic interaction and analyze the vertex activity associated with such events. These topics are discussed along with ArgoNeuT's automated reconstruction software, currently capable of fully reconstructing the muon and finding the event vertex in neutrino interactions.

The ArgoNeuT LAr-TPC: A dedicated experiment for neutrino cross section measurement at FNAL

ArgoNeuT, a Liquid Argon Time Projection Chamber (LAr-TPC), has recently collected thousands of neutrino and anti-neutrino events between 0.1 and 10 GeV in the NuMI beamline at Fermilab (FNAL). Among other issues, the experiment will measure the cross section of the neutrino and anti-neutrino Charged Current Quasi-Elastic (CCQE) interaction on Ar target and analyze the vertex activity associated with such events. Outcomes from the reconstruction of the events provide the main subject of this paper.

Status of ArgoNeuT, a study of v-interactions using a Liquid Argon TPC in the NuMI beam at Fermilab

The Liquid Argon Time Projection Chamber (LArTPC) technology is a leading candidate for a 100-kiloton class detector for electron neutrino appearance in a long-baseline muon-neutrino beam and for nucleon decay within the stable Argon nucleus, both with excellent efficiency and background rejection. The US has taken its first steps toward development of the technology by constructing and operating small LArTPC detectors, the latest being the ¼-ton detector of the ArgoNeuT collaboration. In a recent 6-month run in the low-energy configuration of the NuMI neutrino beam at Fermilab, the collaboration recorded a large sample of neutrino events. This paper reports on the characteristics of that data, the preliminary steps to reduce the data to a sample of neutrino-induced events, and a description of an event consistent with a charged current quasi-elastic electron-neutrino interaction.

Nuclear effects in neutral current quasi-elastic neutrino interactions

The interpretation of the charged (CCQE) and neutral (NCE) current quasi elastic events collected by the MiniBooNE Collaboration involves a number of unresolved issues. While it has been suggested that the data can be explained in terms of an effective nucleon axial mass, MA, the results of our theoretical calculations suggest that the CCQE and NCE samples cannot be described by the same value of MA. We argue that the disagreement between theory and data may arise from the uncertainties associated with the flux average procedure. We also analyze the role of the strange quark in NCE interactions and find that, due to a cancellation between proton and neutron contributions, it turns out to be negligible.

Electron Correlation Effects on the Femtosecond Dephasing Dynamics ofE22Excitons in (6,5) Carbon Nanotubes

Highly nonlinear pump fluence dependence was observed in the ultrafast one-color pump-probe responses excited by 38 fs pulses resonant with the E(22) transition in a room-temperature solution of (6,5) carbon nanotubes. The differential probe transmission (ΔT/T) at the peak of the pump-probe response (τ = 20 fs) was measured for pump fluences from ∼10(13) to 10(17) photons/pulse cm(2). The onset of saturation is observed at ∼2 × 10(15) photons/pulse cm(2) (∼8 × 10(5) excitons/cm). At pump fluences >4 × 10(16) photons/pulse cm(2) (∼1.6 × 10(6) excitons/cm), ΔT/T decreases as the pump fluence increases. Analogous signal saturation behavior was observed for all measured probe delays. Despite the high exciton density at saturation, no change in the E(22) population decay rate was observed at short times (<300 fs). The pump probe signal was modeled by a third-order perturbation theory treatment that includes the effects of inhomogeneous broadening. The observed ΔT/T signal is well-fit by a pump-fluence-dependent dephasing rate linearly dependent on the number of excitons created by the pump pulse. Therefore, the observed nonlinear pump intensity dependence is attributed to the effects of quasi-elastic exciton-exciton interactions on the dephasing rates of single carbon nanotubes. The low fluence total dephasing time is 36 fs, corresponding to a homogeneous width of 36 meV (290 cm(-1)), and the derived E(22) inhomogeneous width is 68 meV (545 cm(-1)). These results are contrasted with photon-echo-derived parameters for the E(11) transition.

Neutrino and antineutrino quasielastic interactions with nuclei

We investigate the interaction of neutrinos and antineutrinos with nuclei. We explore in particular the role played by the multinucleon excitations which can contaminate the quasielastic cross section. For neutrinos the multinucleon term produces a sizable increase of the quasielastic cross section. Part of the effect arises from tensor correlations. For antineutrinos this influence is smaller owing to the axial-vector interference which increases the relative importance of the terms which are not affected by these multinucleon excitations.

Collisions between discrete spatiotemporal dissipative Ginzburg-Landau solitons in two-dimensional photonic lattices

Abstract Systematic results of collisions between discrete spatiotemporal dissipative Ginzburg-Landau solitons in two-dimensional photonic lattices are reported. The generic outcomes are identified for (i) the collision of two identical solitons located in the corner, at the edge, and in the center of the photonic lattice, and for (ii) the collision of two non-identical corner and edge solitons located at different distances from the boundaries of the photonic lattice. Depending on the values of the kick (collision momentum) and of the nonlinear (cubic) gain, the collision scenarios include soliton merging, creation of an extra soliton, soliton bouncing, soliton spreading, and quasi-elastic (symmetric) interactions.

The physics impact of proton track identification in future megaton-scale water Cherenkov detectors

In this paper, we investigate the impact in future megaton-scale water Cherenkov detectors of identifying proton Cherenkov rings. We estimate the expected event rates for detected neutral current and charged current quasi-elastic neutrino interactions from atmospheric neutrinos in a megaton-scale Super-Kamiokande-like detector with both 40% and 20% photo-cathode coverage. With this sample we examine the prospects for measuring the neutrino oscillation pattern, and searching for sterile neutrinos. We also determine the size of selected charged current quasi-elastic samples in a 300-kton fiducial volume Super-Kamiokande-like detector from examples of both conventional super-beams and beta-beams proposed in the literature. With these samples, it is shown that full kinematic neutrino reconstruction using the outgoing proton can improve the reconstructed energy resolution, and give good neutrino versus anti-neutrino tagging capabilities, adding important capabilities to water Cherenkov detectors in future projects. We determine the beam parameters necessary to make use of this technique and present distributions of neutrino and anti-neutrino selection efficiencies.