Wed·Sep 11, 2024Wednesday·September 11, 2024

1. 01*

   Fragmentation of 1.2 A GeV ${}^7$Be nuclei in nuclear photographic emulsion

   N.K. Kornegrutsa · D.A. Artemenkov🇷🇺 · V. Bradnova · P.I. Zarubin🇷🇺 · I.G. Zarubina · R.R. Kattabekov · K. Z. Mamatkulov · P. A. Rukoyatkin · V. V. Rusakova

   The charge topology of peripheral fragmentation of 1.2 A GeV ${}^7$Be nuclei in a nuclear emulsion is presented. The dissociation of ${}^7$Be nuclei via the channels ${}^7$Be${\to }^4$He + ${}^3$He, ${}^7$Be$\to$2${}^3$He + n and ${}^7$Be${\to }^4$He + 2${}^1$H is considered in detail. It is found that in the channel ${}^7$Be${\to }^4$He + 2${}^1$H, events related to the channel ${}^7$Be${\to }^6$Be + n with the cascade decay ${}^6$Be${\to }^4$He + 2p account for about 27 %.

   nucl-ex0 citations
2. 02*

   An Update on the Hypothetical X17 Particle

   A.J. Krasznahorky🇭🇺 · A. Krasznahorkay🇭🇺 · M. Csatlós🇭🇺 · J. Timár🇭🇺 · M. Begala🇭🇺 · A. Krakó🇭🇺 · I. Rajta🇭🇺 · I. Vajda🇭🇺 · N.J. Sas🇭🇺

   Recently, when examining the differential internal pair creation coefficients of ${}^8$Be, ${}^4$He and ${}^{12}$C nuclei, we observed peak-like anomalies in the angular correlation of the e${}^{+}$e${}^{-}$ pairs. This was interpreted as the creation and immediate decay of an intermediate bosonic particle with a mass of $m_X{c}^2\approx$ 17~MeV, receiving the name X17 in subsequent publications. Our results initiated a significant number of new experiments all over the world to detect the X17 particle and determine its properties. In this paper we will give an overview of the experiments the results of which are already published, and the ones closest to being published. We will also introduce our latest results obtained for the X17 particle by investigating the e${}^{+}$e${}^{-}$ pair correlations in the decay of the Giant Dipole Resonance (GDR) of ${}^8$Be.

   nucl-exUniverse(2024)·18 citations
3. 03*

   Big Bang Nucleosynthesis

   Ryan Cooke (Centre for Extragalactic Astronomy, Durham University)🇬🇧

   One of the most compelling pieces of evidence of the Hot Big Bang model is the realisation and confirmation that some nuclides were created shortly after the Big Bang. This process is referred to as Big Bang nucleosynthesis (or, sometimes, primordial nucleosynthesis), and is the end-product of putting neutrons and protons in a hot, expanding Universe. Big Bang nucleosynthesis currently provides our earliest test of cosmology, and it is the only experiment currently designed that is simultaneously sensitive to all four known fundamental forces: the gravitational force, the electromagnetic force, the strong force and the weak force. Our theoretical understanding of Big Bang nucleosynthesis and the measurement of the primordial abundances together represents one of the strongest pillars of the standard cosmological model. In this chapter, we will develop an intuitive understanding of Big Bang nucleosynthesis, discuss modern calculations of this process, and provide a summary of the current state-of-the-art measurements that have been made. Overall, Big Bang nucleosynthesis is in remarkable agreement with various cosmological probes, and it is this agreement that serves to strengthen our confidence in the general picture of cosmology that we have today.

   ↳ astro-ph.COnucl-exnucl-th18 citations
4. 04*

   Beam energy dependence of net-hyperon yield and its implication on baryon transport mechanism

   Chun Yuen Tsang🇺🇸 · Rongrong Ma🇺🇸 · Prithwish Tribedy🇺🇸 · Zhangbu Xu🇺🇸

   In the constituent quark model, each quark inside a baryon carries 1/3 unit of the baryon number. An alternative picture exists where the center of a Y-shaped topology of gluon fields, called the baryon junction, carries a unit baryon number. Studying baryon transport over a large rapidity gap ($\delta y$) in nuclear collisions provides a possible tool to distinguish these two pictures. A recent analysis of global data on net-proton yield at mid-rapidity in Au+Au collisions showed an exponential dependence on $\delta y$ and the exponential slope does not vary with event centrality, favoring the baryon junction picture. Since junctions are flavor blind, hyperons -- baryons containing valence strange quarks -- are expected to exhibit a similar behavior as the proton. This study aims to test this prediction by analyzing hyperon yields in Au+Au collisions at various energies. We observe that net-hyperon yields, after correcting for the strangeness production suppression, adhere to the expected exponential form. The extracted slope parameters for net-$\Lambda$, net-$\Xi$ and net-$\Omega$ are consistent with each other and with those of net-proton within uncertainties, and exhibit no centrality dependence, further substantiating the baryon junction picture. Various implementations of the \texttt{PYTHIA} event generator, primarily based on valence quarks for baryon transport, are unable to simultaneously describe the slope parameters for all baryons.

   ↳ nucl-thnucl-exPLB(2025)·3 citations
5. 05*

   Alpha decay law of excited nuclei and its role in stellar decay rates

   D. F. Rojas-Gamboa · N. G. Kelkar🇨🇴 · O. L. Caballero

   $\alpha$ decay is one of the prominent decay modes in the nucleosynthesis of heavy and super-heavy elements synthesized at temperatures of the order of Giga Kelvin. To facilitate the investigation of the role played by the $\alpha$ decay half-lives of thermally excited nuclei in nucleosynthesis calculations, an empirical formula based on a model for the $\alpha$ decay of nuclei in their ground and excited states to daughter nuclei in their ground or excited states is presented. Constants appearing in the analytical expression for the $\alpha$ decay half-life obtained within the model are treated as adjustable parameters and fitted to experimental data on 342 $\alpha$ decays in the range of 82 $\le Z_p\le$ 94, to obtain an excitation energy-dependent decay law. Under the assumption that thermal equilibrium has been reached between nuclear states, temperature ($T$)-dependent half-lives, $t_{1/2}(T)$, for several of the experimentally studied $\alpha$ emitters with 65 $\le Z_p\le$ 94 are presented using available data on the half-lives of excited nuclei. Though the general trend is a decrease in $t_{1/2}(T)$ at elevated temperatures, exceptional cases with increased half-lives are found in the case of some isomeric states. A list of such isomers provided in this work motivates future work involving considerations of their thermal equilibration and role in shaping kilonova light curves.

   ↳ nucl-thastro-ph.SRnucl-exPRC(2024)·5 citations
6. 06*

   Baryon stopping and charge deposition in heavy-ion collisions due to gluon saturation

   Oscar Garcia-Montero🇩🇪 · Sören Schlichting🇩🇪

   We compute baryon and electric charge deposition in high-energy heavy-ion collisions using the Color Glass Condensate (CGC) Effective Field Theory, where at leading order charge is deposited through multiple scatterings of valence quarks with a saturated gluon target. A simplified phenomenological formula is derived to describe charge deposition, from which the parametrical dependence with collisional energy and geometry can be extracted. We present an approximate analytical prediction of the so-called baryon stopping parameter ${\alpha }_B$, which shows excellent agreement with the state-of-the art extractions of ${\alpha }_B$ from experimental data. These results are further validated using the McDIPPER framework, by computing charge deposition at midrapidity across a range of collision energies ($\sqrt{s_{\mathrm{NN}}}=62.4-5020$ GeV).

   ↳ hep-phnucl-exnucl-thPRC(2025)·9 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.