Wed·Apr 2, 2025Wednesday·April 2, 2025

1. 01*

   First measurement of D${}^{\ast +}$ vector spin alignment in Pb$-$Pb collisions at $\sqrt{{\mathbf{s}}_{\mathrm{NN}}}=5.02$ TeV

   ALICE Collaboration

   The first measurement of prompt D${}^{\ast +}$-meson spin alignment in ultrarelativistic heavy-ion collisions with respect to the direction orthogonal to the reaction plane is presented. The spin alignment is quantified by measuring the element ${\rho }_{00}$ of the diagonal spin-density matrix for prompt D${}^{\ast +}$ mesons with $4<p_{\mathrm{T}}<30$ GeV/$c$ in two rapidity intervals, $|y|<0.3$ and $0.3<|y|<0.8$, in central ($0-10$%) and midcentral ($30-50$%) Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV. Evidence of spin alignment ${\rho }_{00}>1/3$ has been found for $p_{\mathrm{T}}>15$ GeV/$c$ and $0.3<|y|<0.8$ with a significance of $3.1\sigma$. The measured spin alignment of prompt D${}^{\ast +}$ mesons is compared with the one of inclusive J$/\psi$ mesons measured at forward rapidity ($2.5<y<4$).

   nucl-exhep-exJHEP(2025)·17 citations
2. 02*

   Precision Measurement of (Net-)proton Number Fluctuations in Au+Au Collisions at RHIC

   The STAR Collaboration

   We report precision measurements on cumulants ($C_n$) and factorial cumulants (${\kappa }_n$) of (net-)proton number distributions up to fourth-order in Au+Au collisions from phase II of the Beam Energy Scan program at RHIC. (Anti-)protons are selected at midrapidity ($|y|<0.5$) within a transverse momentum range of $0.4<p_T<2.0$ GeV/$c$. The collision energy and centrality dependence of these cumulants are studied over center-of-mass energies $\sqrt{s_{NN}}$ = 7.7 -- 27 GeV. Relative to various non-critical-point model calculations and peripheral collision 70-80\% data, the net-proton $C_4/C_2$ measurement in 0-5\% collisions shows a minimum around 19.6 GeV for significance of deviation at $\sim 2$ -- $5\sigma$. In addition, deviations from non-critical baselines around the same collision energy region are also seen in proton factorial cumulant ratios, especially in ${\kappa }_2/{\kappa }_1$ and ${\kappa }_3/{\kappa }_1$. Dynamical model calculations including a critical point are called for in order to understand these precision measurements.

   nucl-exPRL(2025)·110 citations
3. 03*

   New candidate polymeric wavelength shifters for noble liquid detectors

   M. Kuźniak🇵🇱 · S. Choudhary🇵🇱 · S. Pawłowski🇵🇱 · A. F. V. Cortez🇵🇱 · M. Kaczorowski🇵🇱 · M. Kumosiński🇵🇱 · A. Abramowicz🇵🇱 · T. Łęcki🇵🇱 · G. Nieradka🇵🇱 · T. Sworobowicz🇵🇱 · D. Jamanek🇵🇱

   Polymeric wavelength shifters are of particular interest for large liquid argon detectors. Inspired by the success of polyethylene naphthalate (PEN), other new polymers exhibiting a similar type of excimer fluorescence were investigated. We report on the preliminary results of the first cryogenic wavelength shifting test of a solution-cast film of PVN, poly(2-vinyl naphthalene). Significant brittleness was identified as a factor potentially limiting the use of PVN. However, clear signs of wavelength shifting were observed, with the overall efficiency and time response comparable to those of PEN.

   ↳ astro-ph.IMhep-exnucl-exphysics.ins-detJINST(2025)·0 citations
4. 04*

   Illustrating the liquid gas transition of nuclear matter in QCD

   Fei Gao🇨🇳 · Yi Lu🇨🇳 · Si-xue Qin🇨🇳 · Zhan Bai🇨🇳 · Lei Chang🇨🇳 · Yu-xin Liu🇨🇳

   We demonstrate that the liquid-gas transition of nuclear matter can be rigorously described with the quantum chromodynamics by combining the quark gap equation and the Faddeev equation of nucleon. Our investigation focuses on this transition at zero temperature and finite chemical potential, revealing a finite difference between the gas and liquid solution of the quark propagator. This difference emerges from the shift of the nucleon pole mass in medium, which is generated in the nucleon channel of the quark gap equation. We prove that such a difference is precisely the contour contribution from the shift of the nucleon pole. The resulting discontinuity manifests as a first-order phase transition and fundamentally determines both the nuclear binding energy and the saturation density. We then derive an analytical relation between the binding energy and the sigma term of the nucleon, yielding a binding energy of $E/A=15.9\text{MeV}$. Furthermore, by establishing the relation between the nuclear saturation density and the vector charge of nucleon in association with the binding energy, we determine the saturation density to be $n_{\text{B}}^0=0.15{\text{fm}}^{-3}$.

   ↳ nucl-thhep-phhep-thnucl-exPRD(2025)·4 citations
5. 05*

   Multiplicity-dependent inclusive J/$\psi$ production at forward rapidity in pp collisions at $\sqrt{\mathbf{s}}=13$ TeV

   ALICE Collaboration

   This paper presents a study of the inclusive forward $J/\psi$ yield as a function of forward charged-particle multiplicity in pp collisions at $\sqrt{s}=13$ TeV using data collected by the ALICE experiment at the CERN LHC. The results are presented in terms of relative $J/\psi$ yields and relative charged-particle multiplicities with respect to these quantities obtained in inelastic collisions having at least one charged particle in the pseudorapidity range $|\eta |<1$. The $J/\psi$ mesons are reconstructed via their decay into ${\mu }^{+}{\mu }^{-}$ pairs in the forward rapidity region ($2.5<y<4$). The relative multiplicity is estimated in the forward pseudorapidity range which overlaps with the $J/\psi$ rapidity region. The results show a steeper-than-linear increase of the $J/\psi$ yields versus the multiplicity. They are compared with previous measurements and theoretical model calculations.

   ↳ hep-exnucl-exJHEP(2025)·6 citations
6. 06*

   Transverse spin polarization as a novel probe of medium-induced transverse-momentum-broadening effect

   Xin-yu Qin🇨🇳 · Yu-Kun Song🇨🇳 · Shu-yi Wei🇨🇳

   The transverse polarization of $\Lambda$ hyperons within unpolarized jets originates from the transverse-momentum-dependent (TMD) fragmentation function $D_{1T}^{\perp }(z,p_T,{\mu }^2)$. In the vacuum environment, the QCD evolution of this TMD fragmentation function is governed by the Collins-Soper equation. However, in the presence of the quark-gluon plasma (QGP) medium, the jet-medium interaction induces a transverse-momentum-broadening effect that modifies the QCD evolution. As a result, the transverse spin polarization of $\Lambda$ hyperons in relativistic heavy-ion collisions differs from that in $pp$ collisions. We demonstrate that this difference serves as a sensitive probe for studying jet-medium interaction, offering a novel perspective through the spin degree of freedom.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2026)·3 citations
7. 07*

   Scattering Observables from Few-Body Densities and Compton Scattering on 6Li

   Alexander Long🇺🇸 · Harald W. Griesshammer🇺🇸

   The dynamics of scattering on light nuclei is numerically expensive using standard methods. Fortunately, recent developments allow one to factor the relevant quantities for a given probe into a convolution of an $n$-body Transition Density Amplitude (TDA) and the interaction kernel for a given probe. These TDAs depend only on the target, and not the probe; they are calculated once for each set of kinematics and can be used for different interactions. The kernels depend only on the probe, and not on the target; they can be reused for different targets and different kinematics. The calculation of TDAs becomes numerically difficult for more than four nucleons, but we discuss a new solution through the use of a Similarity Renormalization Group transformation, and a subsequent back-transformation. This technique allows for extending the TDA method to heavier nuclei such as 6Li. We present preliminary results for Compton scattering on 6Li and compare with available data, anticipating an upcoming, more thorough study. We also discuss ongoing extensions to pion-photoproduction and other reactions on light nuclei.

   ↳ nucl-thnucl-exPoS(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.