Mon·Oct 21, 2024Monday·October 21, 2024

1. 01*

   Femtoscopy using Lévy-distributed sources at NA61/SHINE

   Barnabas Porfy (for the NA61/SHINE Collaboration)🇭🇺

   In the recent years, research studies in high-energy physics have confirmed the creation of the strongly interacting quark-gluon plasma (sQGP) in ultra-relativistic nucleus-nucleus collisions. NA61/SHINE at CERN SPS investigates hadronic matter properties by varying collision energy ($\sqrt{s_{\mathrm{NN}}}\approx 5.3,6.2,7.7,8.8,12$, and 16.8 GeV) and systems (such as p+p, p+Pb, Be+Be, Ar+Sc, Xe+La, Pb+Pb). Utilizing femtoscopic correlations, we can unveil the space-time structure of the hadron emitting source. Our focus is on femtoscopic correlations in small to intermediate systems, comparing measurements with source calculations based on Lévy-distributed sources, to explore the pair transverse mass dependence of the Lévy source parameters. The Lévy exponent $\alpha$ is of particular significance, which characterizes the shape of the source and may be connected to the critical exponent $\eta$ near the critical point. Our analysis will reveal that the Lévy shape parameter, $\alpha$, has a slight non-monotonic behaviour as a function of collision energy and that we see a deviation from Gaussian sources. Finally, it will be shown that there is no indication of the critical point at any of the investigated energies.

   nucl-exhep-exPoS(2025)·2 citations
2. 02*

   Neutron-proton pairing in the unstable N=Z nuclei of the f-shell through two-nucleon transfer reactions

   M. Assié🇫🇷 · H. Jacob🇫🇷 · Y. Blumenfeld🇫🇷 · V. Girard-Alcindor🇫🇷

   Pair transfer is a unique tool to study pairing correlations in nuclei. Neutron-proton pairing is investigated in the N=Z nuclei of the f-shell, through the reaction (p,3He) in inverse kinematics, that allows to populate at the same time the lowest J=0+, T=1 (isovector pairing) state and J=1+, T=0 (isoscalar pairing) state. Radioactive beams of 56Ni and 52Fe produced by fragmentation at the GANIL/LISE facility combined with particle and gamma-ray detection make it possible to carry out this study from 48Cr (mid-shell nucleus) to 56Ni (doubly-magic nucleus). The cross-sections were extracted and compared with second-order distorted-wave born approximation (DWBA) calculations performed with neutron-proton amplitudes obtained from shell model calculations with GXPF1 interaction. Very low cross-sections for the J=1+,T=0 state (isoscalar channel) were observed. The cross-section for 56Ni is one of order of magnitude lower than for 40Ca showing a strong reduction of the isoscalar channel in the f-shell as compared to the sd-shell. On the other hand, the increase of the cross-section towards the middle of the shell for the isovector channel points towards a possible superfluid phase.

   nucl-exnucl-thEPJ Web Conf.(2024)·2 citations
3. 03*

   Theoretical description of proton-deuteron interactions using exact two-body dynamic of femtoscopic correlation method

   Wioleta Rzęsa🇵🇱 · Maria Stefaniak🇺🇸 · Scott Pratt🇺🇸

   Modeling proton-deuteron interactions is particularly challenging. Due the deuteron's large size, the interaction can extend over several femtometers. The degree to which it can be modeled as a two-body problem might also be questioned. One way to study these interactions is through femtoscopic correlation measurements of particle pairs, extracting information using available theoretical models. In this work, we examine two approaches for describing proton-deuteron correlations: the Lednicky-Lyuboshits formalism and full numerical solutions of the Schrodinger equation. Our results show that the differences between these methods are significant. Furthermore, we demonstrate that incorporating higher-order partial waves-particularly p-wave -is the essential for accurately capturing the dynamics of proton-deuteron interactions and the full potential of the strong force.

   ↳ nucl-thnucl-exPRC(2025)·13 citations
4. 04*

   Enhancing Precision of Signal Correction in PVES Experiments: The Impact of Bayesian Analysis on the Results of the QWeak and MOLLER Experiments

   Elham Gorgannejad🇨🇦 · Wouter Deconinck🇨🇦 · David S. Armstrong🇺🇸

   The precise measurement of parity-violating asymmetries in parity-violating electron scattering experiments is a powerful tool for probing new physics beyond the Standard Model. Achieving the expected precision requires both experimental and post-processing signal corrections. This includes using auxiliary detectors to distinguish the main signal from background signals and implementing post-measurement corrections, such as the Bayesian statistics method, to address uncontrolled factors during the experiments. Asymmetry values in the scattering of electrons off proton targets in QWeak and P2 and off electron targets in MOLLER are influenced by detector array configurations, beam polarization angles, and beam spin variations. The Bayesian framework refines full probabilistic models to account for all necessary factors, thereby extracting asymmetry values and the underlying physics under specified conditions. For the QWeak experiment, a reanalysis of the inelastic asymmetry measurement using the Bayesian method has yielded a closer fit to measured asymmetries, with uncertainties reduced by 40\% compared to the Monte Carlo minimization method. This approach was successfully applied to simulated data for the MOLLER experiment and is predicted to be similarly effective in P2.

   ↳ hep-phnucl-exphysics.data-an0 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.