The role of initial state and final quench temperature on the aging properties in phase-ordering kinetics

We study numerically the two-dimensional Ising model with non-conserved dynamics quenched from an initial equilibrium state at the temperature $T_i\ge T_c$ to a final temperature $T_f$ below the critical one. By considering processes initiating both from a disordered state at infinite temperature $T_i=\infty$ and from the critical configurations at $T_i=T_c$ and spanning the range of final temperatures $T_f\in [0,T_c[$ we elucidate the role played by $T_i$ and $T_f$ on the aging properties and, in particular, on the behavior of the autocorrelation $C$ and of the integrated response function $\chi$. Our results show that for any choice of $T_f$, while the autocorrelation function exponent $\lambda _C$ takes a markedly different value for $T_i=\infty$ [$\lambda _C(T_i=\infty)\simeq 5/4$] or $T_i=T_c$ [$\lambda _C(T_i=T_c)\simeq 1/8$] the response function exponents are unchanged. Supported by the outcome of the analytical solution of the solvable spherical model we interpret this fact as due to the different contributions provided to autocorrelation and response by the large-scale properties of the system. As changing $T_f$ is considered, although this is expected to play no role in the large-scale/long-time properties of the system, we show important effects on the quantitative behavior of $\chi$. In particular, data for quenches to $T_f=0$ are consistent with a value of the response function exponent $\lambda _\chi=\frac{1}{2}\lambda _C(T_i=\infty)=5/8$ different from the one [$\lambda _\chi \in (0.5-0.56)$] found in a wealth of previous numerical determinations in quenches to finite final temperatures. This is interpreted as due to important pre-asymptotic corrections associated to $T_f>0$.Comment: 25 pages, 15 figures. To appear on Phys. Rev.

The bounce-splash of a viscoelastic drop

This is an entry for the Gallery of Fluid Motion of the 61st Annual Meeting of the APS-DFD (fluid dynamics videos). This video shows the collision and rebound of viscoelastic drops against a solid wall. Using a high speed camera, the process of approach, contact and rebound of drops of a viscoelastic liquid is observed. We found that these drops first splash, similar to what is observed in Newtonian colliding drops; after a few instants, the liquid recoils, recovering its original drop shape and bounce off the wall.Comment: Small manuscript that goes along with a video submission for the Gallery of Fluid Motion of the 61 anual meeting of the APS-DFD, November 200

MicroBooNE: A New Liquid Argon Time Projection Chamber Experiment

Liquid Argon Time Projection Chamber detectors are well suited to study neutrino interactions, and are an intriguing option for future massive detectors capable of measuring the parameters that characterize neutrino oscillations. These detectors combine fine-grained tracking with calorimetry, allowing for excellent imaging and particle identification ability. In this talk the details of the MicroBooNE experiment, a 175 ton LArTPC which will be exposed to Fermilab's Booster Neutrino Beamline starting in 2011, will be presented. The ability of MicroBooNE to differentiate electrons from photons gives the experiment unique capabilities in low energy neutrino interaction measurements.Comment: Proceedings of the 6th International Workshop on Neutrino-Nucleus Interactions in the Few-GeV Region (NuInt09

First Measurement of Muon Neutrino Charged Current Quasielastic (CCQE) Double Differential Cross Section

Using a high statistics sample of muon neutrino charged current quasielastic (CCQE) events, we report the first measurement of the double differential cross section as a function of muon energy and angle for this process. The result features reduced model dependence and supplies the most complete information on neutrino CCQE scattering to date. Measurements of the absolute cross section as a function of neutrino energy and the single differential cross section as a function of 4-momentum transfer squared are also provided, largely to facilitate comparison with prior measurements. This data is of particular use for understanding the axial-vector form factor of the nucleon as well as improving the simulation of low energy neutrino interactions on nuclear targets, which is of particular relevance for experiments searching for neutrino oscillations.Comment: 6 pages, 6 figures, Proceedings of the 6th International Workshop on Neutrino-Nucleus Interactions in the Few-GeV Region (NuInt09

Challenges in Extracting Charged Current Quasi-Elastic Model Information in MiniBooNE's Anti-Neutrino Data

Using a high-statistics sample of anti-neutrino charged current quasi-elastic (CCQE) events, MiniBooNE reports the challenges in measuring parameters within the Relativistic Fermi Gas model. As the CCQE analysis has been completed in MiniBooNE's neutrino data, particular attention is paid to the differences in CCQE interactions between the two running modes.Comment: NuInt '09 conference proceedings. Four pages, five figure

PCAC and coherent pion production by neutrinos

Coherent pion production in low energy neutrino reactions is discussed in the framework of the partially conserved axial vector current theory (PCAC). The role of lepton mass effects in suppressing production of positively charged pions is discussed. Instead of using models of pion nucleus scattering, the available data on pion carbon scattering are implemented for an analysis of the PCAC prediction. Our results agree well with the published upper limits for positively charged production but are much below the recent MiniBooNE result for neutral pion production.Comment: 6 pages, 7 figures, writeup of talk presented at NUINT 200

Search for neutrino charged current coherent pion production at SciBooNE

SciBooNE is a neutrino experiment measuring the neutrino cross sections on carbon in the one GeV region. We have performed a search for charged current coherent pion production from muon neutrinos scattering on carbon, \nu_\mu 12^C \to \mu 12^C \pi^+. No evidence for coherent pion production is observed. We set 90% confidence level upper limits on the cross section ratio of charged current coherent pion production to the total charged current cross section at 0.67\times 10^{-2} at mean neutrino energy 1.1 GeV and 1.36 \times 10^{-2} at mean neutrino energy 2.2 GeV. The kinematic distributions of the final data sample are also presented.Comment: 6 pages, 6 figures, Proceedings of the 6th International Workshop on Neutrino-Nucleus Interactions in the Few-GeV Region (NuInt09

Search for Antineutrino Charged Current Coherent Pion Production at SciBooNE

The SciBooNE experiment (Fermilab) recently published results of a search for charged current coherent pion production in neutrino mode: muon neutrinos scattering on carbon. The results of this study are that no evidence for coherent pion production is observed, and SciBooNE set 90% confidence level upper limits on the cross section ratio of charged current coherent pion production to the total charged current cross section. Recently proposed new coherent pion models predict a production of charged current coherent pion events just below the SciBooNE's upper limit. Motivated by this, we performed a search for charged current coherent pion production using SciBooNE's collected antineutrino data since antineutrino data are expected to be more sensitive to look at coherent pion production than neutrino data. This paper describes preliminary results of a search for antineutrino charged current coherent pion production at the SciBooNE experiment.Comment: 6 pages to be appeared in the proceedings for NuInt09 proceeding

Charged-Current Neutral Pion production at SciBooNE

SciBooNE, located in the Booster Neutrino Beam at Fermilab, collected data from June 2007 to August 2008 to accurately measure muon neutrino and anti-neutrino cross sections on carbon below 1 GeV neutrino energy. SciBooNE is studying charged current interactions. Among them, neutral pion production interactions will be the focus of this poster. The experimental signature of neutrino-induced neutral pion production is constituted by two electromagnetic cascades initiated by the conversion of the neutral pion decay photons, with an additional muon in the final state for CC processes. In this poster, I will present how we reconstruct and select charged-current muon neutrino interactions producing neutral pions in SciBooNE.Comment: NuInt09 poster proceedings, 4 page