Fri·Apr 4, 2025Friday·April 4, 2025

1. 01*

   $\beta$-delayed spectroscopy of ${}^{80}$Ge${}_{48}$ and competition between Gamow-Teller and first-forbidden transitions in ${}^{80g+m}$Ga${}_{49}$ $\beta$ decay

   R. Li · D. Verney I. Matea · M. N. Harakeh · C. Delafosse · F. Didierjean · S. Ebata · L. A. Ayoubi · H. Al Falou · G. Benzoni · F. Le Blanc · V. Bozkurt · M. Ciemała and 19 other authors

   The $\beta$-delayed spectroscopy of ${}^{80}$Ge has been studied using sources of ground and low-lying isomeric states of ${}^{80}$Ga. A hybrid $\gamma$-ray spectrometer was used, composed of high-purity germanium (HPGe) detectors for low-energy $\gamma$-ray detection, phoswich detectors from the PARIS array for high-energy $\gamma$ rays and a plastic detector for $\beta$ tagging. The new decay level schemes are presented, with 13 and 14 states $\beta$ populated by ${}^{80g}$Ga and ${}^{80m}$Ga, respectively, being reported for the first time. We quantitatively compare summed intensities of first-forbidden and previously reported Gamow-Teller $\beta$ transitions [R. Li et al., \href{https://doi.org/10.1103/PhysRevC.111.034303}{Phys. Rev. C 111, 034303 (2025)}]. The upper-limit fractions of first-forbidden transitions contributing to the decays of ${}^{80g}$Ga and ${}^{80m}$Ga are (48.0 $\pm$ 2.7)$\%$ and (47.9 $\pm$ 3.3)$\%$ of the observed total $\beta$ transition intensities of (78.2 $\pm$ 2.5)$\%$ and (82.2 $\pm$ 3.7)$\%$, respectively. Notably, the half-lives decrease in accordance with the upper limits of (48.0 $\pm$ 6.0)$\%$ [3.67(20) s $\to$ 1.91(3) s] and (47.9 $\pm$ 7.2)$\%$ [3.01(19) s $\to$ 1.57(1) s] for ${}^{80g}$Ga and ${}^{80m}$Ga, respectively, when including first-forbidden transitions, in contrast to those by Gamow-Teller transitions only.

   nucl-exPRC(2025)·3 citations
2. 02*

   Measurement of charged hadron multiplicity in Au+Au collisions at $\sqrt{{\text{s}}_{\text{NN}}}=200$ GeV with the sPHENIX detector

   sPHENIX Collaboration: M. I. Abdulhamid🇺🇸 · U. Acharya🇺🇸 · E. R. Adams🇺🇸 · G. Adawi🇺🇸 · C. A. Aidala🇺🇸 · Y. Akiba🇯🇵 · M. Alfred🇺🇸 · S. Ali🇺🇸 · A. Alsayegh🇺🇸 · S. Altaf🇺🇸 · H. Amedi🇺🇸 · D. M. Anderson🇺🇸 and 293 other authors

   The pseudorapidity distribution of charged hadrons produced in Au+Au collisions at a center-of-mass energy of $\sqrt{s_{\mathrm{NN}}}=200$ GeV is measured using data collected by the sPHENIX detector. Charged hadron yields are extracted by counting cluster pairs in the inner and outer layers of the Intermediate Silicon Tracker, with corrections applied for detector acceptance, reconstruction efficiency, combinatorial pairs, and contributions from secondary decays. The measured distributions cover $|\eta |<1.1$ across various centralities, and the average pseudorapidity density of charged hadrons at mid-rapidity is compared to predictions from Monte Carlo heavy-ion event generators. This result, featuring full azimuthal coverage at mid-rapidity, is consistent with previous experimental measurements at the Relativistic Heavy Ion Collider, thereby supporting the broader sPHENIX physics program.

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

   Measurement of the transverse energy density in Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV with the sPHENIX detector

   sPHENIX Collaboration: M. I. Abdulhamid🇺🇸 · U. Acharya🇺🇸 · E. R. Adams🇺🇸 · G. Adawi🇺🇸 · C. A. Aidala🇺🇸 · Y. Akiba🇯🇵 · M. Alfred🇺🇸 · S. Ali🇺🇸 · A. Alsayegh🇺🇸 · S. Altaf🇺🇸 · H. Amedi🇺🇸 · D. M. Anderson🇺🇸 and 293 other authors

   This paper reports measurements of the transverse energy per unit pseudorapidity ($d{E}_T/d\eta$) produced in Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV, performed with the sPHENIX detector at the Relativistic Heavy Ion Collider (RHIC). The results cover the pseudorapidity range $\left|\eta \right|<1.1$ and constitute the first such measurement performed using a hadronic calorimeter at RHIC. Measurements of $d{E}_T/d\eta$ are presented for a range of centrality intervals and the average $d{E}_T/d\eta$ as a function of the number of participating nucleons, $N_{\mathrm{part}}$, is compared to a variety of Monte Carlo heavy-ion event generators. The results are in agreement with previous measurements at RHIC, and feature an improved granularity in $\eta$ and improved precision in low-$N_{\mathrm{part}}$ events.

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

   Accessing the deuteron source with pion-deuteron femtoscopy in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV

   ALICE Collaboration

   Femtoscopy of non-identical particle pairs has been instrumental for precision measurements of both two-particle sources and the final-state interactions in high-energy elementary and heavy-ion collisions. The majority of measurements assessing the source properties are based on identical particle pairs, providing direct access to the characteristics of the single-particle source. The work in this paper demonstrates, via femtoscopy measurements of charged pion--deuteron pairs in Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV, the feasibility of accessing the characteristics of the single-particle femtoscopic source by using particle pairs with large mass differences such as pions and deuterons. The first experimental results of the measurement of deuteron source sizes in ultrarelativistic heavy-ion collisions are presented. The results show good agreement with the trend derived from other charged hadrons such as pions, kaons, and protons as a function of transverse mass, indicating similar source properties.

   nucl-exhep-exPRC(2025)·5 citations
5. 05*

   First observation of ultra-long-range azimuthal correlations in low multiplicity pp and p-Pb collisions at the LHC

   ALICE Collaboration

   This study presents the first observation of ultra-long-range two-particle azimuthal correlations with pseudorapidity separation of ($|\Delta \eta |>5.0$) in proton-proton (pp) and ($|\Delta \eta |>6.5$) in proton-lead (p-Pb) collisions at the LHC, down to and below the minimum-bias multiplicity. Two-particle correlation coefficients ($V_{2\Delta }$) are measured after removing non-flow (jets and resonance decays) contributions using the template-fit method across various multiplicity classes, providing novel insights into the origin of long-range correlations in small systems. Comparisons with the 3D-Glauber + MUSIC + UrQMD hydrodynamic model reveal significant discrepancies at low multiplicities, indicating possible dynamics beyond typical hydrodynamic behavior. Initial-state models based on the Color Glass Condensate framework generate only short-range correlations, while PYTHIA simulations implemented with the string-shoving mechanism also fail to describe these ultra-long-range correlations. The results challenge existing paradigms and question the underlying mechanisms in low-multiplicity pp and p-Pb collisions. The findings impose significant constraints on models describing collective phenomena in small collision systems and advance the understanding of origin of long-range correlations at Large Hadron Collider (LHC) energies.

   nucl-exhep-ex9 citations
6. 06*

   Observation of deuteron and antideuteron formation from resonance-decay nucleons

   ALICE Collaboration

   High-energy hadronic collisions generate environments characterized by temperatures above 100 MeV [1,2], about 100,000 times hotter than the center of the Sun. It is therefore currently unclear how light (anti)nuclei with mass number A of a few units, such as the deuteron, ${}^3$He, or ${}^4$He, each bound by only a few MeV, can emerge from these collisions [3,4]. The ALICE collaboration reports that deuteron-pion momentum correlations in proton-proton (pp) collisions provide model-independent evidence that about 90% of the observed (anti)deuterons are produced in nuclear reactions [5] following the decay of short-lived resonances, such as the $\Delta (1232)$. These findings, obtained by the ALICE experiment at the Large Hadron Collider (LHC) resolve a gap in our understanding of nucleosynthesis in ultra-relativistic hadronic collisions. Beyond offering insights on how (anti)nuclei are formed in hadronic collisions, the results can be employed in the modeling of the production of light and heavy nuclei in cosmic rays [6] and dark matter decays [7,8].

   nucl-exhep-exNature(2025)·26 citations
7. 07*

   Centrality dependence of charged-particle pseudorapidity density at midrapidity in Pb-Pb collisions at $\sqrt{{\text{s}}_{\mathrm{NN}}}=5.36$ TeV

   ALICE Collaboration

   The ALICE Collaboration reports its first LHC Run 3 measurements of charged-particle pseudorapidity density at midrapidity in Pb-Pb collisions at a centre-of-mass energy per nucleon pair of $\sqrt{s_{\mathrm{NN}}}=5.36$ TeV. Particle multiplicity in high-energy collisions characterises the system geometry, constrains particle-production mechanisms, and is used to estimate initial energy density. Multiplicity also acts as a reference for subsequent measurements as a function of centrality. In this letter, for the first time, charged particles are reconstructed using the upgraded ALICE Inner Tracking System and Time Projection Chamber, while the collision centrality is determined by measuring charged-particle multiplicities with the Fast Interaction Trigger system. Pseudorapidity density, $\mathrm{d}{N}_{\mathrm{ch}}/\mathrm{d}\eta$, is presented, averaged over events, for various centrality classes. Results are shown as a function of pseudorapidity and the average number of participating nucleons ($⟨N_{\mathrm{part}}⟩$) in the collision. The average charged-particle pseudorapidity density ($⟨\mathrm{d}{N}_{\mathrm{ch}}/\mathrm{d}\eta ⟩$) at midrapidity ($|\eta |<0.5$) is 2047 $\pm$ 54 for the 5% most central collisions. The value of $⟨\mathrm{d}{N}_{\mathrm{ch}}/\mathrm{d}\eta ⟩$ normalised to $⟨N_{\mathrm{part}}⟩/2$ as a function of $\sqrt{s_{\mathrm{NN}}}$ follows the trend established in previous measurements in heavy-ion collisions. Theoretical models based on mechanisms for particle production in nuclear collisions that involve the formation of quark-gluon plasma medium and models based on individual nucleon-nucleon interactions are compared to the data.

   nucl-exhep-ex18 citations
8. 08*

   Recent results on strangeness enhancement in small collision systems with ALICE

   Sara Pucillo (for the ALICE Collaboration)🇮🇹

   Quantum Chromodynamics (QCD) predicts that, at sufficiently high temperature and energy density, nuclear matter undergoes a phase transition from confined hadrons to a deconfined state of quarks and gluons known as the quark-gluon plasma (QGP). One of the historically proposed signatures of QGP formation is strangeness enhancement (SE), characterized by an increased production of strange hadrons in heavy-ion collisions relative to proton--proton (pp) interactions. At the LHC, the ALICE experiment has measured a continuous increase in the strange-to-non-strange hadron yield ratios as a function of midrapidity charged-particle multiplicity, not only in large systems like Pb--Pb but also in small systems such as pp and p--Pb. The origin of SE in small systems is still under debate, motivating further experimental investigations. This article presents recent ALICE analyses that offer complementary insights into the phenomenon. These include (i) multi-differential studies using event-shape observables such as transverse spherocity and the concept of effective energy, and (ii) the first measurement of multiplicity distributions of strange and multi-strange hadrons, P(${\text{n}}_S$), in pp collisions.

   nucl-exhep-ex2 citations
9. 09*

   Characterization of nuclear breakup as a function of hard-scattering kinematics using dijets measured by ATLAS in $p$+Pb collisions

   ATLAS Collaboration

   This Letter analyzes the sensitivity of event geometry estimators to the initial-state kinematics of hard scattering in proton-lead collisions. This analysis uses dijets as a proxy for the parton-parton scattering configuration, correlating it with event geometry estimators, namely the energy deposited in the Zero-Degree Calorimeter and the transverse energy recorded in the Forward Calorimeter in the Pb-going direction. The analysis uses data recorded by the ATLAS detector at the Large Hadron Collider with a nucleon-nucleon center-of-mass energy of 8.16 TeV, corresponding to an integrated luminosity of 56 nb${}^{-1}$. The jets are measured within the pseudorapidity interval $-$2.8 $<$ $\eta$ $<$ 4.5, where positive $\eta$ values correspond to the direction of the proton beam. Results are presented as a function of the Bjorken-$x$ of the parton originating from the proton, $x_p$. Both event geometry estimators are found to be dependent on $x_p$, with the energy deposited in the Zero-Degree Calorimeter about six times less sensitive to $x_p$ compared with the transverse energy deposited in the Forward Calorimeter.

   nucl-exhep-exPLB(2026)·2 citations
10. 10*

    Indications for freeze-out of charge fluctuations in the quark-gluon plasma at the LHC

    Jonathan Parra🇺🇸 · Roman Poberezhniuk🇺🇦 · Volker Koch🇺🇸 · Claudia Ratti🇺🇸 · Volodymyr Vovchenko🇺🇸

    The D-measure of net-charge fluctuations quantifies the variance of net charge in strongly interacting matter. It was introduced over 20 years ago as a potential signal of quark-gluon plasma (QGP) in heavy-ion collisions, where it is expected to be suppressed due to the fractional electric charges of quarks. Measurements have been performed at RHIC and LHC, but the conclusion has been elusive in the absence of quantitative calculations for both scenarios. We address this issue by employing a recently developed formalism of density correlations and incorporate resonance decays, local charge conservation, and experimental kinematic cuts. We find that the hadron gas scenario is in fair agreement with the ALICE data for $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV Pb-Pb collisions only when a very short rapidity range of local charge conservation is enforced, while the QGP scenario is in excellent agreement with experimental data and largely insensitive to the range of local charge conservation. A Bayesian analysis of the data utilizing different priors yields moderate evidence for the freeze-out of charge fluctuations in the QGP phase relative to hadron gas. The upcoming high-fidelity measurements from LHC Run 2 will serve as a precision test of the two scenarios.

    ↳ hep-phnucl-exnucl-thPRL(2025)·8 citations
11. 11*

    Isospin kaon anomaly and its consequences

    Francesco Giacosa🇵🇱 · Martin Rohrmoser🇵🇱

    Isospin symmetry is well fulfilled in the QCD vacuum, as evidenced by small mass differences of isospin partners and suppressed isospin-violating decays. Recently, the NA61/SHINE collaboration reported an unexpectedly large isospin-violating charged-to-neutral kaon ratio in Ar-Sc heavy-ion collisions (HIC).Using a quark recombination approach, we introduce a function of kaon multiplicities that reduces to unity in the isospin-symmetric limit independently of the scattering energy and type of nuclei. Using this quantity, we show that nucleus-nucleus collisions violate isospin sizably (at the $6.4\sigma$--level), while proton-proton data on kaon multiplicities do not. We predict other isospin-violating enhancements in HIC, such as the proton-to-neutron ratio $p/n\sim 1.2$ and the hyperon ratio ${\Sigma }^{+}/{\Sigma }^{-}\sim 1.4$. Finally, we extend the approach to antiquarks in the initial state, useful for e.g. pion-nucleus scattering reactions.

    ↳ nucl-thhep-phnucl-exEPJC(2025)·2 citations
12. 12*

    Mapped interacting boson model for nuclear structure studies

    Kosuke Nomura🇯🇵

    The present status of the mapped interacting boson model studies on nuclear structure is reviewed. With the assumption that the nuclear surface deformation induced by the multi-nucleon dynamics is simulated by bosonic degrees of freedom, the interacting-boson Hamiltonian that provides energy spectra and wave functions is determined by mapping the potential energy surface that is obtained from self-consistent mean-field calculations based on the energy density functional onto the corresponding energy surface of the boson system. This procedure has been shown to be valid in general cases of the quadrupole collective states, and has allowed for systematic studies on spectroscopic properties of medium-heavy and heavy nuclei, including those that are far from the line of $\beta$ stability. The method has been extended to study nuclear structure phenomena that include shape phase transitions and coexistence, octupole deformation and collectivity, and the coupling of the single-particle to collective degrees of freedom, which is crucial to describe structures of odd nuclei, and $\beta$ and $\beta \beta$ decays.

    ↳ nucl-thnucl-exEPJA(2025)·7 citations
13. 13*

    Revealing the harmonic structure of nuclear two-body correlations in high-energy heavy-ion collisions

    Thomas Duguet🇫🇷 · Giuliano Giacalone🇨🇭 · Sangyong Jeon🇨🇦 · Alexander Tichai🇩🇪

    Smashing nuclei at ultrarelativistic speeds and analyzing the momentum distribution of outgoing debris provides a powerful method to probe the many-body properties of the incoming nuclear ground states. Within a perturbative description of initial-state fluctuations in the quark-gluon plasma, we express the measurement of anisotropic flow in ultra-central heavy-ion collisions as the quantum-mechanical average of a specific set of operators measuring the harmonic structure of the two-body azimuthal correlations among nucleons in the colliding states. These observables shed a new light on spatial correlations in atomic nuclei, while enabling us to test the complementary pictures of nuclear structure delivered by low- and high-energy experiments on the basis of state-of-the-art theoretical approaches rooted in quantum chromodynamics.

    ↳ nucl-thhep-exhep-phnucl-exPRL(2025)·24 citations
14. 14*

    Rapidity spectra in high-energy collisions and longitudinal nuclear suppression from nonadditive statistics

    Trambak Bhattacharyya🇵🇱 · Maciej Rybczyński🇵🇱 · Zbigniew Włodarczyk🇵🇱

    We investigate the longitudinal nuclear suppression factor defined by a scaled ratio of rapidity distributions. To study this experimental observable, we describe three approaches involving numerical and analytical calculations. We first approach this problem by conducting model studies using EPOS, FTFP${}_{BERT}$, and HIJING, and notice that while EPOS shows a decreasing trend of this ratio at forward/backward rapidities, the latter two model calculations display an increment of the ratio. The analytical approaches involve, first, the quasi-exponential distribution obtained from the Tsallis statistics, and second, the nonadditive Boltzmann transport equation in the relaxation time approximation. We notice that our analytical results satisfactorily describe NA61 experimental data (for $\sqrt{s_{NN}}$=6.3, 7.6, 8.8, 12.3, and 17.3 GeV) for the negatively charged pions.

    ↳ nucl-thhep-exhep-phnucl-exPLB(2026)·1 citation
15. 15*

    D${}^0$-meson-tagged jet axes difference in proton-proton collisions at $\sqrt{\text{s}}=5.02$ TeV

    ALICE Collaboration

    Heavy-flavor quarks produced in proton--proton (pp) collisions provide a unique opportunity to investigate the evolution of quark-initiated parton showers from initial hard scatterings to final-state hadrons. By examining jets that contain heavy-flavor hadrons, this study explores the effects of both perturbative and non-perturbative QCD on jet formation and structure. The angular differences between various jet axes, $\Delta R_{\mathrm{axis}}$, offer insight into the radiation patterns and fragmentation of charm quarks. The first measurement of D${}^0$-tagged jet axes differences in pp collisions at $\sqrt{s}=5.02$ TeV by the ALICE experiment at the LHC is presented for jets with transverse momentum $p_{\mathrm{T}}^{\mathrm{ch}\mathrm{jet}}\ge 10$ $\mathrm{GeV}/c$ and D${}^0$ mesons with $p_{\mathrm{T}}^{{\mathrm{D}}^0}\ge 5$ $\mathrm{GeV}/c$. In this D${}^0$-meson-tagged jet measurement, three jet axis definitions, each with different sensitivities to soft, wide-angle radiation, are used: the Standard axis, Soft Drop groomed axis, and Winner-Takes-All axis. Measurements of the radial distributions of D${}^0$ mesons with respect to the jet axes, $\Delta R_{\mathrm{axis}-{\mathrm{D}}^0}$, are reported, along with the angle, $\Delta R_{\mathrm{axis}}$, between the three jet axes. The D${}^0$ meson emerges as the leading particle in these jets, closely aligning with the Winner-Takes-All axis and diverging from the Standard jet axis. The results also examine how varying the sensitivity to soft radiation with grooming influences the orientation of the Soft Drop jet axis, and uncover that charm-jet structure is more likely to survive grooming when the Soft Drop axis is further from the D${}^0$ direction, providing further evidence of the dead-cone effect recently measured by ALICE.

    ↳ hep-exnucl-exPRD(2025)·4 citations
16. 16*

    Investigating the response of single pad and hybrid pixel detectors (Si, GaAs, CdTe, CZT) for 226Ra and 137Cs

    G. Chelkov · S. Abou El-Azm · U. Kruchonak · T.H.B. Phi · G. Lavrov · V. Rozhkov · R. Sotenskii · A. Lapkin

    The development of hybrid pixel detectors for particle detection with high spatial resolution in high energy physics experiments has spun off a number of developments with applications in imaging, especially biomedical imaging, and also imaging in X-ray astronomy and medical application. The energy resolution of pixel detector and cluster size in depends on applied voltage and compression between pixel detector and pad detector have no may attention especially in case of pixel detector . The purpose of this work was to compare the characteristics of using pixel and single pad detectors made of three semiconductor materials (Si, GaAs and CdTe) under the same conditions using Alpha and gamma rays. This paper studies more details the energy resolution, cluster size and signal magnitude of three type of pixel detectors (Si, GaAs:Cr, CdTe) and compression with three pad detectors (Si, GaAs, CdTe) in dependence on applied voltage using 226Ra and 137Cs, the results of dependence of resolution, cluster size and signal magnitude on applied voltage are presented for pixel detectors and pad detectors.

    ↳ physics.ins-detnucl-exJINST(2025)·0 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.