Thu·May 15, 2025Thursday·May 15, 2025

1. 01*

   Heavy-Ion and Fixed-Target Physics at LHCb

   Krista Smith (on behalf of the LHCb collaboration)🇺🇸

   The LHCb experiment, designed for searches of new physics in beauty and charm hadron decays, has been recording data at the Large Hadron Collider since 2010. The physics program incorporates $p$$p$, $p$A, and AA collisions, ultra-peripheral interactions, and a unique fixed-target program. LHCb is a general purpose experiment covering the forward region, measuring particles from $p_T>0$ at forward pseudorapidity $2<\eta <5$. Currently the LHCb collaboration consists of eight working groups, including the Ions and Fixed-Target (IFT) working group. Since the Moriond QCD conference in March 2023, the IFT working group has submitted eleven physics analyses for journal publication, and here we report on five of these.

   nucl-ex1 citation
2. 02*

   Rapidity and multiplicity dependence of charged-particle flow in $p$Pb collisions at $\sqrt{s_{NN}}=8.16$ TeV

   R. Aaij · A.S.W. Abdelmotteleb · C. Abellan Beteta · F. Abudinén · T. Ackernley · A. A. Adefisoye · B. Adeva · M. Adinolfi · P. Adlarson · C. Agapopoulou · C.A. Aidala · Z. Ajaltouni and 1139 other authors

   The elliptic and triangular flow of charged particles are measured using two-particle angular correlations in $p$Pb collisions in the pseudorapidity range \cal{2.0 $<|\eta |<$ 4.8}. The data sample was collected by the LHCb experiment in 2016 at a centre-of-mass energy per nucleon pair of $\sqrt{s_{NN}}=8.16$ TeV, containing in total approximately 1.5 billion collision events. Non-flow contributions are obtained in low-multiplicity collisions and subtracted to extract the flow harmonics. The results are presented as a function of event multiplicity and hadron transverse momentum. Comparisons with a full (3+1)D dynamic model indicate that it overestimates the measured elliptic flow. A comparison between the forward and backward regions reveals no significant differences in flow parameters, suggesting that final-state effects may dominate over initial-state effects in the origin of flow in small systems.

   nucl-exhep-exJHEP(2025)·6 citations
3. 03*

   Symmetry properties of pair correlations in heavy deformed nuclei

   G. Palkanoglou · A. Gezerlis🇨🇦

   Nucleons are known to form pairing correlations with various types of spin-symmetries. Spin-singlet neutron-neutron and proton-proton pairing is abundant in the nuclear chart but spin-triplet and mixed-spin proton-neutron pairing correlations have also been predicted to form at least in the ground states of certain nuclei. A realistic candidate region is that of the lightest Lanthanides where it was recently demonstrated that the nuclear deformation expected to emerge enhances spin-triplet pairing correlations. In this paper we provide the details of the deformed multimodal Hartree-Fock-Bogolyubov theory that lead to this conclusion, as well as the details of the effects identified. We present in detail the response of different pairing correlations to various deformation modes and calculate their signatures in the odd-even staggering of masses. This paper provides a detailed discussion, and some resolutions, on the long-standing question ``what is the effect of nuclear deformation on the various pairing correlations?''

   ↳ nucl-thcond-mat.supr-connucl-ex2 citations
4. 04*

   Photonuclear Tomography in Ultraperipheral Heavy-Ion Collisions

   J.D. Baker🇺🇸 · C.A. Bertulani🇺🇸 · Victor P. Goncalves🇧🇷

   We present a theoretical investigation of photonuclear tomography as a novel technique for probing the internal structure of nuclei. In this approach, ultraperipheral heavy-ion collisions (UPCs) serve as a source of intense fluxes of virtual photons, which induce coherent production of vector mesons. By analyzing the probabilities and cross sections of these photon-induced processes, we propose a methodology for reconstructing the spatial distribution of nucleons within the nucleus. Our framework provides a systematic way to access information on the nuclear geometry probed in UPCs, offering new opportunities for studies of nuclear structure using particle production as a probe. Numerical calculations for selected examples illustrate the feasibility and potential of this method.

   ↳ nucl-thhep-phnucl-exPRC(2025)·1 citation
5. 05*

   Neutrino-less double beta decay in the $\nu$ Standard Model

   Vincenzo Cirigliano🇺🇸 · Wouter Dekens🇺🇸 · Sebastián Urrutia Quiroga🇺🇸

   We perform a comprehensive study of the $3+3$ Type-I seesaw model for a broad range of right-handed mass scales (from keV to 10 TeV). We take into account and, in some cases, update the constraints from a large number of high- and low-energy experiments and study the implications on neutrino-less double beta ($0\nu \beta \beta$) decay experiments. We illustrate our findings through profile likelihood plots for the half-life $T_{1/2}^{0\nu }$ and two-dimensional plots correlating $T_{1/2}^{0\nu }$ to neutrino masses. We find that in this simple class of models for Majorana neutrino masses, current and next-generation $0\nu \beta \beta$ decay experiments have a broad discovery potential in both the normal and inverted orderings of the spectrum of light active neutrinos.

   ↳ hep-phnucl-exnucl-th1 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.