Fri·Sep 20, 2024Friday·September 20, 2024

1. 01*

   Probing exotic cross-shell interactions at N=28 with single-neutron transfer on 47K

   C. J. Paxman🇬🇧 · A. Matta🇫🇷 · W. N. Catford🇬🇧 · G. Lotay🇬🇧 · M. Assié🇫🇷 · E. Clément🇫🇷 · A. Lemasson🇫🇷 · D. Ramos🇫🇷 · N. A. Orr🇫🇷 · F. Galtarossa🇫🇷 · V. Girard-Alcindor🇫🇷 · J. Dudouet🇫🇷 and 67 other authors

   We present the first measurement of the ${}^{47}$K($d,p\gamma$)${}^{48}$K transfer reaction, performed in inverse kinematics using a reaccelerated beam of ${}^{47}$K. The level scheme of ${}^{48}$K has been greatly extended with nine new bound excited states identified and spectroscopic factors deduced. Detailed comparisons with SDPF-U and SDPF-MU shell-model calculations reveal a number of discrepancies with these results, and a preference for SDPF-MU is found. Intriguingly, an apparent systematic overestimation of spectroscopic factors and a poor reproduction of the energies for 1${}^{-}$ states suggests that the mixing between the $\pi s_{1/2}^1{d}_{3/2}^4$ and $\pi s_{1/2}^2{d}_{3/2}^3$ proton configurations in ${}^{48}$K is not correctly described using current interactions, challenging our descriptions of light $N=28$ nuclei.

   nucl-exPRL(2025)·4 citations
2. 02*

   Measurement of the inclusive isolated-photon production cross section in pp and Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV

   ALICE Collaboration

   The ALICE Collaboration at the CERN LHC has measured the inclusive production cross section of isolated photons at midrapidity as a function of the photon transverse momentum ($p_{\mathrm{T}}^{\gamma }$), in Pb$-$Pb collisions in different centrality intervals, and in pp collisions, at centre-of-momentum energy per nucleon pair of $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV. The photon transverse momentum range is between 10-14 and 40-140 GeV/$c$, depending on the collision system and on the Pb$-$Pb centrality class. The result extends to lower $p_{\mathrm{T}}^{\gamma }$ than previously published results by the ATLAS and CMS experiments at the same collision energy. The covered pseudorapidity range is $|{\eta }^{\gamma }|<0.67$. The isolation selection is based on a charged particle isolation momentum threshold $p_{\mathrm{T}}^{\mathrm{iso},\mathrm{ch}}=1.5$ GeV/$c$ within a cone of radii $R=0.2$ and $0.4$. The nuclear modification factor is calculated and found to be consistent with unity in all centrality classes, and also consistent with the HG-PYTHIA model, which describes the event selection and geometry biases that affect the centrality determination in peripheral Pb$-$Pb collisions. The measurement is compared to next-to-leading order perturbative QCD calculations and to the measurements of isolated photons and Z${}^0$ bosons from the CMS experiment, which are all found to be in agreement.

   nucl-exhep-exEPJC(2025)·13 citations
3. 03*

   First observation of strange baryon enhancement with effective energy in pp collisions at the LHC

   ALICE Collaboration

   The production of (multi-)strange hadrons is measured at midrapidity in proton--proton collisions at $\sqrt{s}=13$ TeV as a function of the local charged-particle multiplicity in the pseudorapidity interval $|\eta |<0.5$ and of the very-forward energy measured by the ALICE Zero-Degree Calorimeters. The latter provides information on the effective energy, i.e. the energy available for particle production in the collision once subtracted from the centre-of-mass energy. The yields of K${}_{\mathrm{S}}^0$, $\Lambda +\bar{\Lambda }$, and ${\Xi }^{-}+{\overline{\Xi }}^{+}$ per charged-particle increase with the effective energy. In addition, this work exploits a multi-differential approach to decouple the roles of local multiplicity and effective energy in such an enhancement. The results presented in this article provide new insights into the interplay between global properties of the collision, such as the initial available energy in the event, and the locally produced final hadronic state, connected to the charged-particle multiplicity at midrapidity. Notably, a strong increase of strange baryon production with effective energy is observed for fixed charged-particle multiplicity at midrapidity. These results are discussed within the context of existing phenomenological models of hadronisation implemented in different tunes of the PYTHIA 8 event generator.

   nucl-exhep-exJHEP(2025)·7 citations
4. 04*

   Measurements at forward rapidity of elliptic flow of charged hadrons and open-heavy-flavor muons in Au$+$Au collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV

   PHENIX Collaboration: N.J. Abdulameer · U. Acharya · A. Adare · C. Aidala · N.N. Ajitanand · Y. Akiba · M. Alfred · S. Antsupov · K. Aoki · N. Apadula · H. Asano · C. Ayuso and 357 other authors

   We present the first forward-rapidity measurements of elliptic anisotropy of open-heavy-flavor muons at the BNL Relativistic Heavy Ion Collider. The measurements are based on data samples of Au$+$Au collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV collected by the PHENIX experiment in 2014 and 2016 with integrated luminosity of 14.5~nb${}^{-1}$. The measurements are performed in the pseudorapidity range $1.2<|\eta |<2$ and cover transverse momenta $1<p_T<4$~GeV/$c$. The elliptic flow of charged hadrons as a function of transverse momentum is also measured in the same kinematic range. We observe significant elliptic flow for both charged hadrons and heavy-flavor muons. The results show clear mass ordering of elliptic flow of light- and heavy-flavor particles. The magnitude of the measured $v_2$ is comparable to that in the midrapidity region. This indicates that there is no strong longitudinal dependence in the quark-gluon-plasma evolution between midrapidity and the rapidity range of this measurement at $\sqrt{s_{{}_{NN}}}=200$~GeV.

   nucl-exPRC(2025)·3 citations
5. 05*

   Measurement of elliptic flow of J$/\psi$ in $\sqrt{s_{{}_{NN}}}=200$ GeV Au$+$Au collisions at forward rapidity

   PHENIX Collaboration: N.J. Abdulameer · U. Acharya · A. Adare · C. Aidala · N.N. Ajitanand · Y. Akiba · M. Alfred · S. Antsupov · K. Aoki · N. Apadula · H. Asano · C. Ayuso and 357 other authors

   We report the first measurement of the azimuthal anisotropy of J$/\psi$ at forward rapidity ($1.2<|\eta |<2.2$) in Au$+$Au collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV at the Relativistic Heavy Ion Collider. The data were collected by the PHENIX experiment in 2014 and 2016 with integrated luminosity of 14.5~nb${}^{-1}$. The second Fourier coefficient ($v_2$) of the azimuthal distribution of $J/\psi$ is determined as a function of the transverse momentum ($p_T$) using the event-plane method. The measurements were performed for several selections of collision centrality: 0\%--50\%, 10\%--60\%, and 10\%-40\%. We find that in all cases the values of $v_2(p_T)$, which quantify the elliptic flow of J$/\psi$, are consistent with zero. The results are consistent with measurements at midrapidity, indicating no significant elliptic flow of the J$/\psi$ within the quark-gluon-plasma medium at collision energies of $\sqrt{s_{{}_{NN}}}=200$ GeV.

   nucl-exPRC(2025)·5 citations
6. 06*

   Search for quasi-particle scattering in the quark-gluon plasma with jet splittings in pp and Pb$-$Pb collisions at $\sqrt{{\text{s}}_{\mathrm{NN}}}=5.02$ TeV

   ALICE Collaboration

   The ALICE Collaboration reports measurements of the large relative transverse momentum ($k_{\text{T}}$) component of jet substructure in pp and Pb$-$Pb collisions at center-of-mass energy per nucleon pair $\sqrt{s_{\text{NN}}}=5.02$ TeV. Enhancement in the yield of such large-$k_{\text{T}}$ emissions in head-on Pb$-$Pb collisions is predicted to arise from partonic scattering with quasi-particles of the quark-gluon plasma. The analysis utilizes charged-particle jets reconstructed by the anti-$k_{\text{T}}$ algorithm with resolution parameter $R=0.2$ in the transverse-momentum interval $60<p_{\text{T,ch jet}}<80$ GeV/$c$. The soft drop and dynamical grooming algorithms are used to identify high transverse momentum splittings in the jet shower. Comparison of measurements in Pb$-$Pb and pp collisions shows medium-induced narrowing, corresponding to yield suppression of high-$k_{\text{T}}$ splittings, in contrast to the expectation of yield enhancement due to quasi-particle scattering. The measurements are compared to theoretical model calculations incorporating jet modification due to jet-medium interactions ("jet quenching"), both with and without quasi-particle scattering effects. These measurements provide new insight into the underlying mechanisms and theoretical modeling of jet quenching.

   nucl-exhep-exPRL(2025)·15 citations
7. 07*

   Systematic study of cross section for proton-induced reactions on Neodymium up to 65 MeV using TALYS-1.96 code

   A. Saha🇮🇳

   Systematic study of theoretical estimation of nuclear cross section of charged particle induced reactions on rare earth nuclei has been carried out. The production cross section of the ${}^{150,149,148,146,144,143,141}$Pm and ${}^{149,147}$Nd nuclei were calculated theoretically via proton induced reaction on neodymium using TALYS (version 1.96) code in the default mode, with different combination of nuclear models as well as using adjusted nuclear model parameters from reaction threshold to the proton energy upto 65 MeV. The theoretically computed results were compared with the experimental results taken from EXFOR database and literature, reported by various research groups. Moreover, the effect of the various Level Density Models (LDMs), Preequilibrium Models (PEs), Optical Model Potentials (OMPs), gamma Strength Functions ($\gamma$SFs) in the cross section calculation were taken into consideration. The present theoretical analysis will help to understand the theory of nuclear reaction models and improve the evaluated nuclear data libraries.

   ↳ nucl-thnucl-exCPC(2025)·1 citation
8. 08*

   Efficient transmutation of long-lived fission products in a Gamma Factory beam driven advanced nuclear energy system

   Hu Baolong🇨🇳 · Mieczyslaw Witold Krasny🇫🇷 · Wieslaw Placzek🇵🇱 · Yun Yuan🇨🇳 · Xiaoming Shi🇨🇳 · Kaijun Luo🇨🇳 · Wen Luo🇨🇳

   The Gamma Factory (GF) project aims to generate high-intensity $\gamma$-ray beams of tunable energy and relatively small energy spread. Such beams can be optimized to generate an intense photo-neutron source, capable of driving an advanced nuclear energy system (ANES) for nuclear waste transmutation and supplying electrical power that is necessary for the GF operation mode of the Large Hadron Collider storage ring. In this study, we investigate the feasibility of driving ANES with the GF beam which is optimized to maximize the neutron production rate. The dependence of the ANES thermal power on the distance between the positions of the ANES and the GF $\gamma$-ray source is evaluated. For the $\gamma$-ray beam reaching the intensity of $\sim$$10^{19}$ photons per second, the ANES thermal power could exceed $500$MWt. Under the assumption that ANES operates over $20$ years, the transmutation rate could reach $30\%$ for five typical long-lived fission products (LLFPs): ${}^{79}$Se, ${}^{99}$Tc, ${}^{107}$Pd, ${}^{129}$I, ${}^{137}$Cs. Our comparative studies show that although the neutron production efficiency of the GF $\gamma$-ray beam (per MW of the beam power) is approximately $14$ times lower than that of the $500$MeV proton beam, the overall net ANES power production efficiency for the GF beam driver scheme could be comparable to that of the proton beam driver scheme, while providing additional transmutation capacity, not available for the proton beam driven scheme. It is suggested that the GF-based ANES could provide a viable solution for the efficient transmutation of LLFPs without isotopic separation.

   ↳ physics.acc-phhep-exnucl-exphysics.app-phSci.Rep.(2025)·8 citations
9. 09*

   Exposing the parton-hadron transition within jets with energy-energy correlators in pp collisions at $\sqrt{\text{s}}=5.02$ TeV

   ALICE Collaboration

   This paper presents a fully-corrected measurement of the energy-energy correlator (EEC) within jets in pp collisions. The EEC traces the energy flow as a highly energetic parton undergoes a QCD shower followed by the confinement of partons into hadrons, probing the correlation function of the energy flow inside jets. The EEC observable is measured as a function of the charged particle pair angular distance, $R_{\mathrm{L}}$, for $20<p_{\mathrm{T}}^{\mathrm{ch}\mathrm{jet}}<80$ GeV/$c$. In the perturbative region (large $R_{\mathrm{L}}$), a good agreement between the data and a next-to-leading-log perturbative QCD calculation is observed. In the non-perturbative region (small $R_{\mathrm{L}}$), the data exhibits a linear $R_{\mathrm{L}}$ dependence. There is a transition region in between, characterized by a turnover in the EEC distribution, corresponding to the confinement process. The peak of this transition region is located at $2.39\pm 0.17$ GeV/$c/⟨p_{\mathrm{T}}^{\mathrm{ch}\mathrm{jet}}⟩$ for jets of various energies, indicating a common energy scale for the hadronization process. State-of-the-art Monte Carlo event generators are compared with the measurements, and can be used to constrain the parton shower and hadronization mechanisms.

   ↳ hep-exnucl-exPRD(2026)·73 citations
10. 10*

    Flavor Hierarchy of Jet Energy Correlators inside the Quark-Gluon Plasma

    Wen-Jing Xing🇨🇳 · Shanshan Cao🇨🇳 · Guang-You Qin🇨🇳 · Xin-Nian Wang🇨🇳

    Heavy flavor jets provide ideal tools to probe the mass effect on jet substructure in both vacuum and quark-gluon plasma (QGP). Energy-energy correlator (EEC) is an excellent jet substructure observable owning to its strong sensitivity to jet physics at different scales. We perform a complete realistic simulation on medium modification of heavy and light flavor jet EEC in heavy-ion collisions. A clear flavor hierarchy is observed for jet EEC in both vacuum and QGP due to the mass effect. The medium modification of inclusive jet EEC at different angular scales exhibits very rich structure: suppression at intermediate angles, and enhancement at small and large angles, which can be well explained by the interplay of mass effect, energy loss, medium-induced radiation and medium response. These unique features of jet EEC are shown to probe the physics of jet-medium interaction at different scales, and can be readily validated by upcoming experiments.

    ↳ hep-phnucl-exnucl-thPRL(2025)·40 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.