A careful reanalysis of both Argonne National Laboratory and Brookhaven National Laboratory data for weak single pion production is done. We consider deuteron nuclear effects and normalization (flux) uncertainties in both experiments. We demonstrate that these two sets of data are in good agreement. For the dipole parametrization of $C_5^A(Q^2)$, we obtain $C_5^A(0)=1.19\pm 0.08$, $M_A=0.94\pm 0.03$ GeV. As an application we present the discussion of the uncertainty of the neutral current 1$π^0$ production cross section, important for the T2K neutrino oscillation experiment.
There exists a longstanding disagreement between bubble chamber measurements of the single pion production channel $ν_μp\rightarrow μ^{-}pπ^{+}$ from the Argonne and Brookhaven National Laboratories. We digitize and reanalyse data from both experiments to produce cross-section ratios for various interaction channels, for which the flux uncertainties cancel, and find good agreement between the experiments. By multiplying the cross-section ratio by the well-understood charged current quasi-elastic cross-section on free nucleons, we extract single-pion production cross-sections which do not depen…
Two equations for the calculation of the critical energy required for homogeneous nucleation in a superheated liquid, and the related critical radius of the nucleated vapour bubble, are obtained, the former by the direct application of the first law of thermodynamics, the latter by considering that the bubble formation implies the overcoming of a barrier of the free enthalpy potential. Comparisons with the currently used relationships demonstrate that the sensitivity of the bubble chambers employed in dark matter searches can be sometimes notably overestimated.
The sensitivity to New Physics of a low threshold scintillating argon bubble chamber measuring coherent elastic neutrino-nucleus scattering in reactors is reported. Namely, light scalar mediators, sterile neutrino oscillations, unitarity violation, and non-standard interactions are studied. The results indicate that this detector could be able to set stronger constraints than current limits set by the recent COHERENT measurements. Considering the best scenario, a 100 kg detector located 30 m from a 2000 MW$_{th}$ reactor, a sterile neutrino search would cover most of the space parameter allowe…
The physics reach of a low threshold (100 eV) scintillating argon bubble chamber sensitive to Coherent Elastic neutrino-Nucleus Scattering (CE$ν$NS) from reactor neutrinos is studied. The sensitivity to the weak mixing angle, neutrino magnetic moment, and a light $Z'$ gauge boson mediator are analyzed. A Monte Carlo simulation of the backgrounds is performed to assess their contribution to the signal. The analysis shows that world-leading sensitivities are achieved with a one-year exposure for a 10 kg chamber at 3 m from a 1 MW$_{th}$ research reactor or a 100 kg chamber at 30 m from a 2000 MW…
A re-analysis of some $\bar{p}p$ and $\bar{p}n$ data, at rest and in flight, obtained in bubble chamber experiments, is presented. The ($π^{+}π^{-}$) and ($K_{S}K_{S}$) final states for the channels (2$π^{-}π^{+}$) and ($K_{S}K_{S}π$) are investigated. Evidence for a narrow meson resonance structure, cautiously suggested as $f_{0} (1500)$, is given. In the ($π^{+}π^{-}$) invariant mass distribution from $\bar{p}n$ annihilations in flight, using the method of difference spectra, a very clear evidence for $ρ^{0}, f_{2}(1270)$ and $f_{0} (1500)$ is first time obtained from these data. This re-ana…
We propose a new application of single molecule magnet crystals: their use as "magnetic bubble chambers" for the direct detection of sub-GeV dark matter. The spins in these macroscopic crystals effectively act as independent nano-scale magnets. When anti-aligned with an external magnetic field they form meta-stable states with a relaxation time that can be very long at sufficiently low temperatures. The Zeeman energy stored in this system can be released through localized heating, caused for example by the scattering or absorption of dark matter, resulting in a spin avalanche (or "magnetic def…
PICO bubble chambers have exceptional sensitivity to inelastic dark matter-nucleus interactions due to a combination of their extended nuclear recoil energy detection window from a few keV to $O$(100 keV) or more and the use of iodine as a heavy target. Inelastic dark matter-nucleus scattering is interesting for studying the properties of dark matter, where many theoretical scenarios have been developed. This study reports the results of a search for dark matter inelastic scattering with the PICO-60 bubble chambers. The analysis reported here comprises physics runs from PICO-60 bubble chambers…
Many compelling models predict dark matter coupling to the electromagnetic current through higher multipole interactions, while remaining electrically neutral. Different multipole couplings have been studied, among them anapole moment, electric and magnetic dipole moments, and millicharge. This study sets limits on the couplings for these photon-mediated interactions using non-relativistic contact operators in an effective field theory framework. Using data from the PICO-60 bubble chamber leading limits for dark matter masses between 2.7 GeV/c$^2$ and 24 GeV/c$^2$ are reported for the coupling…
In this work we report the calculation of the charged current total and differential cross sections for weak pion-production with neutrinos and antineutrinos, with the final pion-nucleon pair invariant mass $W_{πN}\lesssim2$GeV. Our results are compared with the recent reanalyzed data from the old bubble chamber experiments, that solved the discrepancy between the ANL and BNL data. We implement a model previously tested for the cuts $W_{πN}<1.4,1.6$ Gev which includes explicitly resonances in the first and second resonance regions, within different approaches for the resonances self energy and…
We show that in the presence of large scale primordial hypermagnetic fields, it is possible to generate an axial asymmetry for a first order electroweak phase transition. This happens during the reflection and transmission of fermions off the true vacuum bubbles, due to the chiral nature of the fermion coupling with the background field in the symmetric phase. We derive and solve the Dirac equation for such fermions and compute the reflection and transmission coefficients for the case when these fermions move from the symmetric to the symmetry broken phase. We also comment on the possible impl…
We describe a procedure to tune the charged hadron multiplicities for deep inelastic events produced by the NEUT neutrino interaction generator. This tuning uses a model based on Koba-Nielsen-Olesen scaling, whose parameters are obtained by fitting multiplicity data from deuterium bubble chamber experiments. After tuning, the multiplicities of the events generated by NEUT are found to be in good agreement with the measurements from the bubble chamber experiments.
The primary advantage of moderately superheated bubble chamber detectors is their simultaneous sensitivity to nuclear recoils from WIMP dark matter and insensitivity to electron recoil backgrounds. A comprehensive analysis of PICO gamma calibration data demonstrates for the first time that electron recoils in C$_3$F$_8$ scale in accordance with a new nucleation mechanism, rather than one driven by a hot-spike as previously supposed. Using this semi-empirical model, bubble chamber nucleation thresholds may be tuned to be sensitive to lower energy nuclear recoils while maintaining excellent elec…
The Bayesian approach for feed-forward neural networks has been applied to the extraction of the nucleon axial form factor from the neutrino-deuteron scattering data measured by the Argonne National Laboratory (ANL) bubble chamber experiment. This framework allows to perform a model-independent determination of the axial form factor from data.. When the low $0.05 < Q^2 < 0.10$ GeV$^2$ data is included in the analysis, the resulting axial radius disagrees with available determinations. Furthermore, a large sensitivity to the corrections from the deuteron structure is obtained. In turn, when the…
We study the scattering of fermions off the true vacuum bubbles nucleated during a first order electroweak phase transition in the presence of a background hypermagnetic field. By considering the limit of an infinitely thin bubble wall, we derive and analytically solve the Dirac equation in three spatial dimensions for left and right chirality modes and compute reflection and transmission coefficients for the case when the fermions move from the symmetric toward the broken symmetry phase. Given the chiral nature of the fermion coupling with the background field in the symmetric phase, an axial…
The MicroBooNE neutrino experiment at Fermilab is constructing a liquid-argon time-projection chamber for the Booster Neutrino Beam to study neutrino oscillations and interactions with nucleons and nuclei, starting in 2014. We describe the experiment and focus on its unique abilities to measure cross sections at low values of $Q^2$. In particular, the neutral-current elastic scattering cross section is especially interesting, as it is sensitive to the contribution of the strange sea quark spin to the angular-momentum of the nucleon, $Δs$. Implications for dark-matter searches are discussed.
We report a theoretical study of the axial Nucleon to Delta(1232) ($N\toΔ$) transition form factors up to one-loop order in relativistic baryon chiral perturbation theory. We adopt a formalism in which the $Δ$ couplings obey the spin-3/2 gauge symmetry and, therefore, decouple the unphysical spin-1/2 fields. We compare the results with phenomenological form factors obtained from neutrino bubble chamber data and in quark models.
We investigate the axial-vector nucleon-to-delta transition form factors in the framework of relativistic baryon chiral perturbation theory at the one-loop order using the complex-mass renormalization scheme. We determine the available six free parameters by fitting to an empirical parametrization of the form factors obtained from the BNL neutrino bubble chamber experiments. A unique feature of our calculation is the prediction of a non-vanishing form factor $C_3^A(Q^2)$. Moreover, our results show a surprising sensitivity to the coupling constant $\texttt{g}_1$ of the leading-order Lagrangian…
We re-evaluate our model predictions in Phys. Rev. D 79, 013002 (2009) for different observables in neutrino induced coherent pion production. This comes as a result of the new improved fit to old bubble chamber data of the dominant axial C_5^A nucleon-to-Delta form factor. We find an increase of 20%-30% in the values for the total cross sections. Uncertainties induced by the errors in the determination of C_5^A are computed. Our new results turn out to be compatible within about $1σ$ with the former ones. We also stress the existing tension between the recent experimental determination of the…
This talk presents some of the results of the re-analysis of [Graczyk et al.] of the bubble chamber data for single pion production induced by neutrino scattering off deuteron. It is shown that ANL and BNL data are statistically consistent. The validity of the Adler relations (between $P_{33}(1232)$ resonance axial form factors) is also investigated.
Neutrino and anti-neutrino induced single-charm production are particularly interesting to study the strange-quark parton distribution function and the threshold effect in the cross-section, associated with the heavy quark production. Over the past 30 years, many experiments have carried out these studies with complementary techniques: calorimetry, bubble chambers and nuclear emulsions. In this paper, we review these data and combine them statistically to extract a world averaged single-charm production cross-section for both neutrino and anti-neutrino.
We discuss different parameterizations of the $C_5^A(q^2)$ $NΔ$ axial form factor, fitted to the old Argonne bubble chamber data for pion production by neutrinos, and we use coherent pion production to test their low $q^2$ behavior. We find moderate effects that will be difficult to observe with the accuracy of present experiments. We also discuss the use of the Rein-Sehgal model for low energy coherent pion production. By comparison to a microscopic calculation, we show the weaknesses of some of the approximations in that model that lead to very large cross sections as well as to the wrong sh…
