Thu·Dec 12, 2024Thursday·December 12, 2024

1. 01*

   Mirror Symmetry Breaking Disclosed in the Decay of Three-Proton Emitter 20Al

   X.-D. Xu🇨🇳 · I. Mukha🇩🇪 · J. G. Li🇨🇳 · S. M. Wang🇨🇳 · L. Acosta🇪🇸 · M. Bajzek🇩🇪 · E. Casarejos🇪🇸 · D. Cortina-Gil🇪🇸 · J. M. Espino🇪🇸 · A. Fomichev🇷🇺 · H. Geissel🇩🇪 · J. Gomez-Camacho🇪🇸 and 16 other authors

   The previously-unknown nucleus 20Al has been observed for the first time by detecting its in-flight decays. Tracking trajectories of all decay products with silicon micro-strip detectors allowed for a conclusion that 20Al is unbound with respect to three-proton (3p) emission. The 3p-decay energy of 20Al ground state has been determined to be 1.93(+0.11,-0.09) MeV through a detailed study of angular correlations of its decay products, 17Ne+p+p+p. This value is much smaller in comparison with the predictions inferred from the isospin symmetry by using the known energy of its mirror nucleus 20N, which indicates a possible mirror symmetry violation in the structure of 3p emitters. Such an isospin symmetry breaking is supported by the calculations of the continuum embedded theoretical frameworks, describing the observed 20Al ground state as an 1p s-wave state with a spin-parity of 1-, which contradicts to the spin-parity (2-) of the 20N ground state. The 20Al ground state decays by sequential 1p-2p emission via intermediate ground state of 19Mg, which is the first observed case of daughter two-proton radioactivity following 1p decay of the parent state.

   nucl-exPRL(2025)·10 citations
2. 02*

   Analysis Note: Directed flow $v_1$ of protons in the Xe+Cs(I) collisions at 3.8 AGeV

   Mikhail Mamamev · Arkadiy Taranenko🇷🇺 · Alexander Demanov · Petr Parfenov🇷🇺 · Valery Troshin

   In this note, we present the directed flow $v_1$ measurements of protons from Xe+Cs(I) collisions at 3.8 AGeV (BM@N run8). We show the datasets, event and track selection cuts, centrality definition, event plane reconstruction and resolution. The $v_1$ results are presented as function of transverse momentum ($p_T$) and rapidity ($y_{cm}$) for 10-30\% central Xe+Cs(I) collisions. The systematic uncertainty study will also be presented and discussed. The $v_1$ measurements are compared with results of JAM transport model calculations and published data from other experiments.

   nucl-exhep-ex1 citation
3. 03*

   Jet substructure of light and heavy flavor jets at RHIC

   Zhuoheng Yang🇺🇸 · Oleh Fedkevych🇺🇸 · Roli Esha🇺🇸

   Jet substructure studies at the Large Hadron Collider have been used to constrain parton distribution functions, test perturbative QCD, measure the strong-coupling constant, and probe the properties of the quark-gluon plasma. We extend these studies to lower energies at the Relativistic Heavy Ion Collider that would additionally allow us to test existing models of non-perturbative physics. In this study, we present a PYTHIA8-based Monte Carlo study of substructure of jets produced in $p+p$ collisions at 200 GeV. The selection criteria is adapted for a feasible measurement at sPHENIX. We consider different types of jet substructure observables such as jet angularities and primary Lund Plane with a special focus on suppression of collinear radiation around emitting heavy quark known as a dead cone effect.

   ↳ hep-phnucl-exnucl-thPRC(2026)·1 citation

* 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.