New articles on Nuclear Experiment

[1] 2406.05273

High-precision measurements of the atomic mass and electron-capture decay $Q$ value of $^{95}$Tc

A direct measurement of the ground-state-to-ground-state electron-capture decay $Q$ value of $^{95}$Tc has been performed utilizing the double Penning trap mass spectrometer JYFLTRAP. The $Q$ value was determined to be 1695.92(13) keV by taking advantage of the high resolving power of the phase-imaging ion-cyclotron-resonance technique to resolve the low-lying isomeric state of $^{95}$Tc (excitation energy of 38.910(40) keV) from the ground state. The mass excess of $^{95}$Tc was measured to be $-$86015.95(18) keV/c$^2$, exhibiting a precision of about 28 times higher and in agreement with the value from the newest Atomic Mass Evaluation (AME2020). Combined with the nuclear energy-level data for the decay-daughter $^{95}$Mo, two potential ultra-low $Q$-value transitions are identified for future long-term neutrino-mass determination experiments. The atomic self-consistent many-electron Dirac--Hartree--Fock--Slater method and the nuclear shell model have been used to predict the partial half-lives and energy-release distributions for the two transitions. The dominant correction terms related to those processes are considered, including the exchange and overlap corrections, and the shake-up and shake-off effects. The normalized distribution of the released energy in the electron-capture decay of $^{95}$Tc to excited states of $^{95}$Mo is compared to that of $^{163}$Ho currently being used for electron-neutrino-mass determination.

[2] 2406.06503

Search for the Chiral Magnetic Effect using Sliding Dumbbell Method in Isobar Collisions ($^{96}_{44}Ru$+$^{96}_{44}Ru$ and $^{96}_{40}Zr$+$^{96}_{40}Zr$) at RHIC

Experiments conducted in the last decade to search for the Chiral Magnetic Effect (CME) in heavy-ion collisions have been inconclusive. The Isobar program at RHIC was undertaken to address this problem. Also, a new approach known as the Sliding Dumbbell Method (SDM) has been developed to study the CME. This method searches for the back-to-back charge separation on an event-by-event basis.

[3] 2406.05200

Decay energy spectrometry for improved nuclear material analysis at the iaea nml

Decay energy spectrometry (DES) is a novel radiometric technique for high-precision analysis of nuclear materials. DES employs the unique thermal detection physics of cryogenic microcalorimeters with ultra-high energy resolution and 100$\%$ detection efficiency to accomplish high precision decay energy measurements. Low-activity nuclear samples of 1 Bq or less, and without chemical separation, are used to provide elemental and isotopic compositions in a single measurement. Isotopic ratio precisions of 1 ppm - 1,000 ppm (isotope dependent), which is close to that of the mass spectrometry, have been demonstrated in 12-hour DES measurements of ~5 Bq samples of certified reference materials of uranium (U) and plutonium (Pu). DES has very different systematic biases and uncertainties, as well as different sensitivities to nuclides, compared to mass-spectrometry techniques. Therefore, the accuracy and confidence of nuclear material assays can be improved by combining this new technique with existing mass-spectrometry techniques. Commercial-level DES techniques and equipment are being developed for the implementation of DES at the Nuclear Material Laboratory (NML) of International Atomic Energy Agency (IAEA) to provide complementary measurements to the existing technologies. The paper describes details of DES measurement methods, as well as DES precision and accuracy to U and Pu standard sources to discuss its capability in analysis of nuclear safeguards samples.

[4] 2406.05240

A General Track Fit based on Triplets

This work presents an analytical solution for a general three-dimensional track fit based on hit triplets. Input to the fit are triplet parameters, which contain information about the triplet geometry (hit positions), the radiation length of the material and the magnetic field. The general fit considers spatial hit and multiple Coulomb scattering uncertainties, and can also be extended to include energy losses. The output of the fit, which is given by an analytical closed-form solution, contains the total momentum and the hit residuals, including the full covariance matrix, thus allowing for easy software alignment of the detector. The fit qualities are calculated for the global track fit as well as for the local hit triplets. This feature allows filtering out triplets with poor fit quality at an early stage of track reconstruction. The fit of local triplets is fully parallelizable, enabling accelerated computation with parallel hardware architectures. The triplet track fit is detector-independent, making it possible to use the same fitting code for all tracking detectors. Only the detector-specific triplet parameters (fit input) depend on the triplet geometries and the magnetic field. Formulas for the calculation of the triplet parameters are given for the most common tracking detector setups, namely a homogeneous magnetic field and a spectrometer using a dipole magnet. Furthermore, an algorithm is presented to calculate tracking parameters for an arbitrary magnetic field configuration. Moreover, this work includes a discussion of track fit biases and presents an extension of the fit to include energy losses. Last but not least, it is proposed to use triplet-based scale parameters that characterize different tracking regimes to accelerate track fits and to optimize the design of future tracking detectors.

[5] 2406.05591

High precision measurements of alpha_s at the future EIC

We present a projection study for the first moments of the inclusive spin structure function for the proton and neutron from simulated doubly-polarized e+p and e+3He collision data expected from the Electron-Ion collider. For detection and extraction of the neutron spin asymmetries from e+3He collisions, we used the double-tagging method which significantly reduces the uncertainty over the traditional inclusive method. Using the Bjorken sum rule, the projected results allow us to determine that the QCD coupling at the Z-pole alpha_s can be measured with a relative precision of 1.3%. This underscores the significance of the EIC for achieving precision determinations of alpha_s.

[6] 2406.05618

Photon induced proton and anti-proton pair production with ultraperipheral heavy ion collisions at RHIC

We investigate proton-antiproton ($p\bar{p}$) pair production via photon-photon fusion in the ultra-peripheral collisions at RHIC, employing a joint impact parameter and transverse momentum dependent formalism. We consider proton exchange, $s$-channel resonance and hand-bag mechanisms, predicting differential distributions of $p\bar p$ production. Our theoretical predictions can be tested against future measurements at RHIC, to enhance our understanding of photon-photon interactions in strong electromagnetic fields.

[7] 2406.05880

Long Range Azimuthal Correlation, Entanglement and Bell Inequality Violation by Spinning Gluons at the LHC

We apply the recently developed concept of the nucleon energy-energy correlator (NEEC) for the gluon sector to investigate the long-range azimuthal angular correlations in proton-proton collisions at the LHC. The spinning gluon in these collisions will introduce a significant nonzero $\cos(2\phi)$ asymmetries in both Higgs Boson and top quark pair productions. The genesis of the $\cos(2\phi)$ correlation lies in the intricate quantum entanglement. Owing to the substantial $\cos(2\phi)$ effect, the NEEC observable in Higgs Boson and $t{\bar t}$ production emerges as a pivotal avenue for delving into quantum entanglement and scrutinizing the Bell inequality at high-energy colliders.

[8] 2406.06058

Feasibility of the observation of $η^{\prime}$ mesic nuclei in the semi-exclusive $^{12}$C($p, dp$) reaction

We study theoretically the feasibility of the semi-exclusive $^{12}$C($p,dp$)$X$ reaction for the observation of $\eta^\prime$ mesic nuclei using the transport model JAM. The semi-exclusive measurements of the ($p,d$) reaction with protons from $\eta^\prime$ non-mesonic two-body absorption ($\eta^\prime NN \to NN$) are found to be critically important for the observation of the $\eta^\prime$ bound states. The Green's function method is used to calculate the momentum spectrum of forward going deuterons corresponding to the excitation energy spectrum of the $\eta^\prime \otimes {}^{11}$C system in the semi-exclusive measurement. The semi-exclusive measurements are considered to be important in general for the $\eta^\prime$ mesic nucleus formation.

[9] 2406.06292

Modeling inclusive electron-nucleus scattering with Bayesian artificial neural networks

We introduce a Bayesian protocol based on artificial neural networks that is suitable for modeling inclusive electron-nucleus scattering on a variety of nuclear targets with quantified uncertainties. Unlike previous applications in the field, which directly parameterize the cross sections, our approach employs artificial neural networks to represent the longitudinal and transverse response functions. In contrast to cross sections, which depend on the incoming energy, scattering angle, and energy transfer, the response functions are determined solely by the energy and momentum transfer to the system, allowing the angular component to be treated analytically. We assess the accuracy and predictive power of our framework against the extensive data in the quasielastic inclusive electron-scattering database. Additionally, we present novel extractions of the longitudinal and transverse response functions and compare them with previous experimental analysis and nuclear ab-initio calculations.