Thu·Sep 19, 2024Thursday·September 19, 2024

1. 01*

   Investigating charm quark energy loss in medium with the nuclear modification factor of D${}^0$-tagged jets

   ALICE Collaboration

   The nuclear modification factor $R_{\mathrm{AA}}$ of charm jets, identified by the presence of a D${}^0$ meson among the jet constituents, has been measured for the first time in Pb-Pb collisions at a centre-of-mass energy per nucleon pair $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV with the ALICE detector at the LHC. The D${}^0$ mesons and their charge conjugates are reconstructed from the hadronic decay D${}^0\to {\mathrm{K}}^{-}{\pi }^{+}$. Jets are reconstructed from D${}^0$-meson candidates and charged particles using the anti-$k_{\mathrm{T}}$ algorithm with jet resolution parameter $R=0.3$, in the jet transverse momentum ($p_{\mathrm{T}}$) range $5<p_{\mathrm{T}}^{\mathrm{ch}\mathrm{jet}}<50$ GeV/$c$ and pseudorapidity $|{\eta }^{\mathrm{ch}\mathrm{jet}}|<0.6$. A hint of reduced suppression in the charm-jet $R_{\mathrm{AA}}$ is observed in comparison to inclusive jets in central Pb-Pb collisions with a significance of about 2$\sigma$ in $20<p_{\mathrm{T}}^{\mathrm{ch}\mathrm{jet}}<50$ GeV/$c$, suggesting the in-medium energy loss to depend on both the difference between quark and gluon coupling strength (Casimir colour-charge effect) and quark mass (dead-cone effect). The data are compared with model calculations that include mass effects in the in-medium energy loss. Among these, LIDO provides the best description of the data, highlighting the role of mass effects in interpreting the results.

   nucl-exhep-exPLB(2026)·5 citations
2. 02*

   Coherent J/$\psi$ photoproduction at midrapidity in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV

   ALICE Collaboration

   The coherent J/$\psi$ photoproduction cross section is measured for the first time at midrapidity in peripheral to semicentral Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV. The centrality differential cross section $\mathrm{d}\sigma /\mathrm{d}y$ is reported for the centrality range 40-90%, together with the doubly-differential cross section ${\mathrm{d}}^2\sigma /\mathrm{d}y\mathrm{d}{p}_{\mathrm{T}}$, extracted in two peripheral centrality classes. The J/$\psi$ mesons are reconstructed in the dielectron channel, in the rapidity interval $|y|<0.9$ using the ALICE central barrel detectors. The J/$\psi$ cross section at midrapidity is statistically compatible to the earlier ALICE measurement at forward rapidity and at the same centre-of-mass energy, and shows only a mild centrality dependence over the covered range. Several sets of theoretical calculations taking into account the hadronic overlap in the collisions but ignoring possible final-state effects from a hot expanding medium are found to give a fairly good description of the current measurements within uncertainties.

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

   Addendum: Dielectron production in proton-proton and proton-lead collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV

   ALICE Collaboration

   This is an addendum to the article [arXiv:2005.11995] "Dielectron production in proton-proton and proton-lead collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV" published in Phys. Rev. C 102 no. 5, (2020) 055204. We update the extracted charm cross section at midrapidity given in Table 3 and Figure 4 (left) of the original publication with the fragmentation fractions of charm quarks in pp collisions published in Phys. Rev. D 105 (2022) L011103.

   nucl-exhep-exPRC(2025)·47 citations
4. 04*

   Investigating the effects of precise mass measurements of Ru and Pd isotopes on machine learning mass modeling

   W. S. Porter🇺🇸 · B. Liu🇺🇸 · D. Ray🇨🇦 · A. A. Valverde🇺🇸 · M. Li · M. R. Mumpower🇺🇸 · M. Brodeur🇺🇸 · D. P. Burdette🇺🇸 · N. Callahan🇺🇸 · A. Cannon · J. A. Clark🇺🇸 · D. E. M. Hoff🇺🇸 and 10 other authors

   Atomic masses are a foundational quantity in our understanding of nuclear structure, astrophysics and fundamental symmetries. The long-standing goal of creating a predictive global model for the binding energy of a nucleus remains a significant challenge, however, and prompts the need for precise measurements of atomic masses to serve as anchor points for model developments. We present precise mass measurements of neutron-rich Ru and Pd isotopes performed at the Californium Rare Isotope Breeder Upgrade facility at Argonne National Laboratory using the Canadian Penning Trap mass spectrometer. The masses of ${}^{108}$Ru, ${}^{110}$Ru and ${}^{116}$Pd were measured to a relative mass precision $\delta m/m\approx 10^{-8}$ via the phase-imaging ion-cyclotron-resonance technique, and represent an improvement of approximately an order of magnitude over previous measurements. These mass data were used in conjunction with the physically interpretable machine learning (PIML) model, which uses a mixture density neural network to model mass excesses via a mixture of Gaussian distributions. The effects of our new mass data on a Bayesian-updating of a PIML model are presented.

   nucl-exPRC(2024)·3 citations
5. 05*

   Pion Boer-Mulders function using a contact interaction

   Dan-Dan Cheng🇨🇳 · Zhu-Fang Cui🇨🇳 · Minghui Ding🇩🇪 · Craig D. Roberts🇨🇳 · Sebastian M. Schmidt🇩🇪

   A symmetry preserving treatment of a vector $\otimes$ vector contact interaction (SCI) is used as the basis for calculations of the two pion transverse momentum dependent parton distribution functions (TMDs); namely, that for unpolarised valence degrees-of-freedom and the analogous Boer-Mulders (BM) function. Amongst other things, the analysis enables the following themes to be addressed: the quark current mass dependence of pion TMDs; the impact of the gauge link model on the positivity constraint that bounds the BM function relative to the unpolarised TMD; the equivalence of direct diagrammatic and light-front wave function TMD calculations; and the size of the BM shift. Interpreted astutely, these SCI results enable one to draw insightful pictures of pion TMDs.

   ↳ hep-phhep-exhep-latnucl-ex+1EPJC(2025)·11 citations
6. 06*

   Photo-nuclear reaction rates of ${}^{157,159}$Ho and ${}^{163,165}$Tm and their impact in the $\gamma$--process

   Hao Cheng · Bao-Hua Sun · Li-Hua Zhu · Motohiko Kusakabe🇨🇳 · Yudong Luo🇨🇳 · Toshitaka Kajino🇨🇳 · Chang-Jian Wang🇨🇳 · Xing-Qun Yao · Chuang-Ye He · Fu-Long Liu · Bing Guo

   Reliable photo-nuclear reaction rates at the stellar conditions are essential to understand the origin of the heavy stable neutron-deficient isotopes between ${}^{74}$Se and ${}^{196}$Hg-p-nuclei, however, many reaction rates of relevance still have to rely on the Hauser-Feshbach model due to rare experimental progress. One such case is in the mass range of 160 for Dy, Er, Ho and Tm isotopes. In this work we attempt to constrain the Hauser-Feshbach model in the TALYS package by reproducing the available experimental data of ${}^{160}$Dy($p,\gamma$)${}^{161}$Ho and ${}^{162}$Er($p,\gamma$)${}^{163}$Tm in the $A\sim 160$ mass region, and examine the effects of level density, gamma strength function and the optical model potential. The constrained model then allows us to calculate the reaction rates of ${}^{157,159}$Ho($\gamma$, $p$) and ${}^{163,165}$Tm($\gamma$, $p$) for the $\gamma$-process nucleosynthesis in carbon-deflagration SNe Ia model. Our recommended rates differ from the JINA REACLIB by more than 1 order of magnitude in the temperature range of 2-3 GK. This results in the changes of final abundance of $p$-nuclei in the $A\sim 160$ mass range by -5.5-3\% from those with JINA, which means that the ($\gamma$, $p$) reactions uncertainty is not predominant for the synthesis of these nuclei.

   ↳ astro-ph.SRnucl-exnucl-thApJ(2024)·1 citation
7. 07*

   Measurement of f${}_1$(1285) production in pp collisions at $\sqrt{\text{s}}$ = 13 TeV

   ALICE Collaboration

   This study presents the first measurement of the f${}_1$(1285) resonance using the ALICE detector in inelastic proton-proton collisions at a center-of-mass energy of 13 TeV. The resonance is reconstructed at midrapidity ($|y|<$ 0.5) through the hadronic decay channel f${}_1(1285)\to {\mathrm{K}}_{\mathrm{S}}^0{\mathrm{K}}^{\pm }{\pi }^{\mp }$. Key measurements include the determination of its mass, transverse-momentum integrated yield, and average transverse momentum. Additionally, the ratio of the transverse-momentum integrated yield of f${}_1$(1285) to pion is compared with calculations from the canonical statistical hadronization model. The model calculation, assuming a zero total strangeness content for f${}_1$(1285), reproduces the data within 1$\sigma$ deviation, shedding light on the quark composition of f${}_1$(1285).

   ↳ hep-exnucl-exPLB(2025)·9 citations
8. 08*

   First measurement of ${\mathrm{D}}_{s1}(1^{+})(2536{)}^{+}$ and ${\mathrm{D}}_{s2}^{\ast }(2^{+})(2573{)}^{+}$ production in proton-proton collisions at $\sqrt{s}=13$ TeV at the LHC

   ALICE Collaboration

   The production yields of the orbitally excited charm-strange mesons ${\mathrm{D}}_{s1}(1^{+})(2536{)}^{+}$ and ${\mathrm{D}}_{s2}^{\ast }(2^{+})(2573{)}^{+}$were measured for the first time in proton-proton (pp) collisions at a center-of-mass energy of $\sqrt{s}=13$ TeV with the ALICE experiment at the LHC. The ${\mathrm{D}}_{s1}^{+}$ and ${\mathrm{D}}_{s2}^{\ast +}$ mesons were measured at midrapidity ($|y|<0.5$) in minimum-bias and high-multiplicity pp collisions in the transverse-momentum interval $2<p_{\mathrm{T}}<24$ GeV/$c$. Their production yields relative to the ${\mathrm{D}}_{\mathrm{s}}^{+}$ ground-state yield were found to be compatible between minimum-bias and high-multiplicity collisions, as well as with previous measurements in ${\mathrm{e}}^{\pm }$p and ${\mathrm{e}}^{+}{\mathrm{e}}^{-}$ collisions. The measured ${\mathrm{D}}_{s1}^{+}/{\mathrm{D}}_{\mathrm{s}}^{+}$ and ${\mathrm{D}}_{s2}^{\ast +}/{\mathrm{D}}_{\mathrm{s}}^{+}$ yield ratios are described by statistical hadronization models and can be used to tune the parameters governing the production of excited charm-strange hadrons in Monte Carlo generators, such as PYTHIA 8.

   ↳ hep-exnucl-exPRD(2025)·3 citations
9. 09*

   $\nu$-point energy correletors with FastEEC: small-$x$ physics from LHC jets

   Ankita Budhraja🇳🇱 · Hao Chen🇺🇸 · Wouter J. Waalewijn🇳🇱

   In recent years, energy correlators have emerged as a powerful tool for studying jet substructure, with promising applications such as probing the hadronization transition, analyzing the quark-gluon plasma, and improving the precision of top quark mass measurements. The projected $N$-point correlator measures correlations between $N$ final-state particles by tracking the largest separation between them, showing a scaling behavior related to DGLAP splitting functions. These correlators can be analytically continued in $N$, commonly referred to as $\nu$-correlators, allowing access to non-integer moments of the splitting functions. Of particular interest is the $\nu \to 0$ limit, where the small momentum fraction behavior of the splitting functions requires resummation. Originally, the computational complexity of evaluating $\nu$-correlators for $M$ particles scaled as $2^{2M}$, making it impractical for real-world analyses. However, by using recursion, we reduce this to $M{2}^M$, and through the FastEEC method of dynamically resolving subjets, $M$ is replaced by the number of subjets. This breakthrough enables, for the first time, the computation of $\nu$-correlators for LHC data. In practice, limiting the number of subjets to 16 is sufficient to achieve percent-level precision, which we validate using known integer-$\nu$ results and convergence tests for non-integer $\nu$. We have implemented this in an update to FastEEC and conducted an initial study of power-law scaling in the perturbative regime as a function of $\nu$, using CMS Open Data on jets. The results agree with DGLAP evolution, except at small $\nu$, where the anomalous dimension saturates to a value that matches the BFKL anomalous dimension.

   ↳ hep-phhep-exnucl-exnucl-thPLB(2025)·13 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.