Search Results (20)

There is evidence that the properties of hadrons are modified in a nuclear medium. Information about the medium modifications of the internal structure of hadrons is fundamental for the study of dense nuclear matter and high-energy processes, including heavy-ion and nucleus–nucleus collisions. At the moment, however, empirical information about medium modifications of hadrons is limited; therefore, theoretical studies are essential for progress in the field. In the present work, we review theoretical studies of the electromagnetic and axial form factors of octet baryons in symmetric nuclear matter. The calculations are based on a model that takes into account the degrees of freedom revealed in experimental studies of low and intermediate square transfer momentum $q^2=-Q^2$: valence quarks and meson cloud excitations of baryon cores. The formalism combines a covariant constituent quark model, developed for a free space (vacuum) with the quark–meson coupling model for extension to the nuclear medium. We conclude that the nuclear medium modifies the baryon properties differently according to the flavor content of the baryons and the medium density. The effects of the medium increase with density and are stronger (quenched or enhanced) for light baryons than for heavy baryons. In particular, the in-medium neutrino–nucleon and antineutrino–nucleon cross-sections are reduced compared to the values in free space. The proposed formalism can be extended to densities above the normal nuclear density and applied to neutrino–hyperon and antineutrino–hyperon scattering in dense nuclear matter. Full article

We investigate quasielastic (anti)neutrino scattering on the ¹²C nucleus utilizing a novel scaling variable, ${\psi }^{*}$. This variable is derived from the interacting relativistic Fermi gas model, which incorporates both scalar and vector interactions, leading to a relativistic effective mass for the interacting nucleons. For inclusive lepton scattering from nuclei, we develop a new scaling function, denoted as $f^{\mathrm{QE}}\left({\psi }^{*}\right)$, based on the coherent density fluctuation model (CDFM). This model serves as a natural extension of the relativistic Fermi gas (RFG) model applicable to finite nuclei. In this study, we compute theoretical predictions and compare them with experimental data from Miner$\nu$a and T2K for inclusive (anti)neutrino cross-sections. The scaling function is derived within the CDFM framework, employing a relativistic effective mass of $m_N^{*}=0.8m_N$. The findings demonstrate a high degree of consistency with experimental data across all (anti)neutrino energy ranges. Full article

The NUCLEUS experiment, currently being commissioned at the Technical University of Munich, is designed to observe coherent elastic neutrino-nucleus scattering ($\mathrm{CE}\nu \mathrm{NS}$) from reactor neutrinos and measure its cross-section with a percent-level precision at recoil energies below $100 \mathrm{eV}$. As a Standard Model process, $\mathrm{CE}\nu \mathrm{NS}$ provides a unique probe into neutrino properties, potential new physics, and background suppression techniques relevant to dark matter experiments. The experiment utilizes gram-scale cryogenic calorimeters operating at $10 \mathrm{mK}$ with an energy threshold of $20 \mathrm{eV}$. Situated at a shallow overburden of 3 m of water equivalent, the experimental site necessitates an advanced shielding strategy combining active vetoes and passive layers to reduce background rates to approximately $100\mathrm{counts}/(\mathrm{kg}·\mathrm{day}·\mathrm{keV})$, as confirmed by full setup simulations. The commissioning phase has successfully demonstrated the stable operation of the cryogenic target detectors, achieving baseline resolutions below $10 \mathrm{eV}$, and the integration of the various shielding systems. Following this milestone, the experiment is set to transition to the EdF Chooz B nuclear reactor in France in 2025, where it will enable precise measurements of $\mathrm{CE}\nu \mathrm{NS}$, contributing to the understanding of neutrino interactions and advancing the field of astroparticle physics. Full article

In our recent publications, we presented neutral-current $\nu$–nucleus cross-sections for the coherent and incoherent channels for some stable Mo isotopes, assuming a Mo detector medium, within the context of the deformed shell model. In these predictions, however, we have not included the contributions in the cross-sections stemming from the stable ^94,96Mo isotopes (abundance of ⁹⁴Mo 9.12% and of ⁹⁶Mo 16.50%). The purpose of the present work is to perform detailed calculations of $\nu$–^94,96Mo scattering cross-sections, for a given energy $E_{\nu }$ of the incoming neutrino, for coherent and incoherent processes. In many situations, the $E_{\nu }$ values range from 15 to 30 MeV, and in the present work, we used $E_{\nu }$ = 15 MeV. Mo as a detector material has been employed by the MOON neutrino and double-beta decay experiments and also from the NEMO neutrinoless double-beta decay experiment. For our cross-section calculations, we utilize the Donnelly–Walecka multipole decomposition method in which the $\nu$–nucleus cross-sections are given as a function of the excitation energy of the target nucleus. Because only the coherent cross-section is measured by current experiments, it is worth estimating what portion of the total cross-section represents the measured coherent rate. This requires the knowledge of the incoherent cross-section, which is also calculated in the present work. Full article

The deformed shell model (DSM), based on Hartree–Fock intrinsic states with angular momentum projection and band mixing, has been found to be quite successful in describing many spectroscopic properties of nuclei in the A = 60–100 region. More importantly, DSM has been used recently with good success in calculating nuclear structure factors, which are needed for a variety of weak interaction processes. In this article, in addition to giving an overview of this, we discuss the applications of DSM to obtain cross-sections for coherent and incoherent neutrino nucleus scattering on ^96,98,100Mo targets and also for obtaining two neutrino double beta decay nuclear transition matrix elements for ¹⁰⁰Mo. Full article

This paper presents a combined analysis of muon neutrino and antineutrino charged-current cross sections at kinematics of relevance for the T2K, MINERvA and MicroBooNE experiments. We analyze the sum, difference and asymmetry of neutrino versus antineutrino cross sections in order to get a better understanding of the nuclear effects involved in these processes. Nuclear models based on the superscaling behavior and the relativistic mean field theory are applied, covering a wide range of kinematics, from hundreds of MeV to several GeV, and the relevant nuclear regimes, i.e., from quasileastic reactions to deep inelastic scattering processes. The NEUT neutrino-interaction event generator, used in neutrino oscillation experiments, is also applied to the analysis of the quasielastic channel via local Fermi gas and spectral function approaches. Full article

DUNE’s Argon time-projecting chambers (TPC) detectors will allow us to conduct precise studies about phenomena that have, until now, seemed too challenging to measure, like tau neutrino $\left({\nu }_{\tau }\right)$ interactions. Cross section measurements are needed to understand how accurate our neutrino-nucleus interaction models are and how accurately we can use them to reconstruct neutrino energy. Quasi-elastic scattering (QE), $\Delta$ resonance production (RES), and deep inelastic scattering (DIS) processes are known to provide dominant contributions in the medium and high neutrino energy to the total cross-section of ${\nu }_{\tau }$(N) and ${\overline{\nu }}_{\tau }$(N). These cross-sections have large systematic uncertainties compared to the ones measured for ${\nu }_{\mu }$ and ${\nu }_e$ and their antiparticles. Studies point out that the reason for these differences is due to the model dependence of the ${\nu }_{\tau }$(N) cross-sections in treating the nuclear medium effects described by the nucleon structure functions, $F_{1N,\cdots ,3N}(x,Q^2)$ for ${\nu }_{\mu }$ and ${\nu }_e$. These proceedings show the semi-theoretical and experimental approach to the estimation of the ${\nu }_{\tau }$(N) and ${\overline{\nu }}_{\tau }$(N) cross-sections in DUNE for the DIS region. We will check the contributions of the additional nucleon structure functions $F_{4N}(x,Q^2)$ and $F_{5N}(x,Q^2)$ and their dependence on Q² and Bjorken-x scale. Full article

This review paper emphasizes the significance of microscopic calculations with quantified theoretical error estimates in studying lepton–nucleus interactions and their implications for electron scattering and accelerator neutrino oscillation measurements. We investigate two approaches: Green’s Function Monte Carlo and the extended factorization scheme, utilizing realistic nuclear target spectral functions. In our study, we include relativistic effects in Green’s Function Monte Carlo and validate the inclusive electron scattering cross section on carbon using available data. We compare the flux-folded cross sections for neutrino-carbon scattering with T2K and MINER$\nu$A experiments, noting the substantial impact of relativistic effects in reducing the theoretical curve strength when compared to MINER$\nu$A data. Additionally, we demonstrate that quantum Monte Carlo-based spectral functions accurately reproduce the quasi-elastic region in electron scattering data and T2K flux-folded cross sections. By comparing results from Green’s Function Monte Carlo and the spectral function approach, which share a similar initial target state description, we quantify errors associated with approximations in the factorization scheme and the relativistic treatment of kinematics in Green’s Function Monte Carlo. Full article

The MicroBooNE liquid argon time projection chamber experiment is pursuing a broad range of neutrino physics measurements, including some of the first high-statistics results for neutrino–argon scattering cross-sections. At the neutrino energies relevant for MicroBooNE and its companion experiments in the Fermilab Short-Baseline Neutrino program, the dominant event topology involves mesonless final states containing one or more protons. A complete description of these events requires modeling the contributions of quasielastic and two-particle, two-hole neutrino interactions, as well as more inelastic reaction modes in which final state pions are reabsorbed by the residual nucleus. Refinements to the current understanding of these processes, informed by new neutrino cross-section data, will enable a precise and reliable interpretation of future measurements of neutrino oscillations and searches for exotic physics processes involving neutrinos. This proceeding presents the first double-differential cross-section results from MicroBooNE for mesonless charged current scattering of muon neutrinos on argon. Full article

The Scintillating Bubble Chamber (SBC) collaboration is developing liquid-noble bubble chambers for the detection of sub-keV nuclear recoils. These detectors benefit from the electron recoil rejection inherent in moderately-superheated bubble chambers with the addition of energy reconstruction provided from the scintillation signal. The ability to measure low-energy nuclear recoils allows the search for GeV-scale dark matter and the measurement of coherent elastic neutrino-nucleus scattering on argon from MeV-scale reactor antineutrinos. The first physics-scale detector, SBC-LAr10, is in the commissioning phase at Fermilab, where extensive engineering and calibration studies will be performed. In parallel, a functionally identical low-background version, SBC-SNOLAB, is being built for a dark matter search underground at SNOLAB. SBC-SNOLAB, with a 10 kg-yr exposure, will have sensitivity to a dark matter–nucleon cross section of $2\times {10}^{-42}$ cm${}^2$ at 1 GeV/$c^2$ dark matter mass, and future detectors could reach the boundary of the argon neutrino fog with a tonne-yr exposure. In addition, the deployment of an SBC detector at a nuclear reactor could enable neutrino physics investigations including measurements of the weak mixing angle and searches for sterile neutrinos, the neutrino magnetic moment, and the light Z’ gauge boson. Full article

The detection and cross-section measurement of Coherent Elastic Neutrino–Nucleus Scattering (CEvNS) are vital for particle physics, astrophysics, and nuclear physics. Therefore, a new CEvNS detection experiment is proposed in China. Undoped CsI crystals, each coupled with two Photon Multiplier Tubes (PMTs), will be cooled down to 77 K and placed at the China Spallation Neutron Source (CSNS) to detect the CEvNS signals produced by neutrinos from stopped pion decays occurring within the Tungsten target of CSNS. Owing to the extremely high light yield of pure CsI at 77 K, even though it only has a neutrino flux 60% weaker than the COHERENT experiment, the detectable signal event rate is still expected to be 0.074/day/kg (0.053/day/kg for COHERENT). Low-radioactivity materials and devices will be used to construct the detector, and strong shielding will be applied to reduce the radioactive and neutron background. Dual-PMT readout should be able to reject PMT dark count background. Using all the strategies mentioned above, we hope to reach a 5.1$\sigma$ signal detection significance within six months of data collection with four 3 kg CsI. This paper will discuss the experiment’s design, as well as the estimation of the signal, various kinds of background, and expected signal sensitivity. Full article

The latest direct measurements of the germanium quenching factor deviate significantly from the standard Lindhard model for nuclear recoil energies at the sub keV region. Here, we show that the recently measured coherent elastic neutrino–nucleus scattering (CE$\nu$NS) data from reactor antineutrinos can be used to probe the quenching factor model, and a 2$\sigma$ improvement can be achieved in the fit to the measured CE$\nu$NS data if the quenching factor is described by a modified Lindhard model with a negative value of q, which is also consistent with the direct quenching factor measurement. Constraints on the parameter space of a light vector or scalar mediator that couples to neutrinos and quarks, and on a neutrino magnetic moment, are also placed by using the measured CE$\nu$NS data, and we find that they are quite sensitive to the quenching factor model at low recoil energies. Full article

The MicroBooNE detector is a liquid argon time projection chamber (LArTPC) with an 85 ton active mass that receives flux from the Booster Neutrino and the Nutrinos from the Main Injector (NuMI) beams, providing excellent spatial resolution of the reconstructed final-state particles. Since 2015, MicroBooNE has accumulated many neutrino and anti-neutrino scattering events with argon nuclei enabling searches for rare interaction channels. The Cabibbo-suppressed production of hyperons in anti-neutrino–nucleus interactions provides sensitivity to a range of effects, including second-class currents, SU(3) symmetry violations and reinteractions between the hyperon and the nuclear remnant. This channel exclusively involves anti-neutrinos, offering an unambiguous constraint on wrong-sign contamination. The effects of nucleon structure and final state interactions are distinct from those affecting the quasielastic channel and modify the $\Lambda$ and $\Sigma$ production cross sections in different ways, providing new information that could help to break their degeneracy. Few measurements of this channel have been made, primarily in older experiments such as Gargamelle. We present the sensitivity of the MicroBooNE experiment to the cross section for direct (Cabibbo-suppressed) $\Lambda$ production in muon anti-neutrino interactions, using anti-neutrinos from the off-axis NuMI beam. Full article

We study the role of short-range correlations, as well as pion and rho loops governing long-range RPA correlations, in nuclear matter properties and response functions. We use an adapted formulation of the Brueckner G-matrix approach to generate a pair correlation function satisfying the Beg–Agassi–Gal theorem, providing a natural cutoff to the loop integrals. We present results for the case of a relativistic chiral theory, including the effects of quark confinement and of the chirally broken vacuum in a version where parameters are directly connected to QCD observables or constrained by well-established hadron phenomenology. This provides a unified and coherent view of the nuclear matter equation of state and the effect of correlations on neutrino–nucleus scattering. Full article

A thorough understanding of neutrino–nucleus interaction physics is crucial to achieving precision goals in broader neutrino physics programs. The complexity of the nuclei comprising the detectors and the limited understanding of their weak response constitute two of the biggest systematic uncertainties in neutrino experiments—both at intermediate energies affecting short- and long-baseline neutrino programs and at lower energies affecting coherent scattering neutrino programs. While electron and neutrino interactions are different at the primary vertex, many underlying relevant physical processes in the nucleus are the same in both cases, and electron scattering data collected with precisely controlled kinematics, large statistics, and high precision allow one to constrain nuclear properties and specific interaction processes. To this end, electron–nucleus scattering experiments provide vital complementary information to test, assess, and validate different nuclear models and event generators intended to be used in neutrino experiments. In fact, for many decades, the study of electron scattering off a nucleus has been used as a tool to probe the properties of that nucleus and its electromagnetic response. While previously existing electron scattering data provide important information, new and proposed measurements are tied closely to what is required for the neutrino program in terms of expanding kinematic reach, the addition of relevant nuclei, and information on the final-state hadronic system. Full article