Tue·Sep 16, 2025Tuesday·September 16, 2025

1. 01*

   Towards a precise measurement of the ${\Lambda }_c^{+}/D^0$ ratio at RHIC

   Joseph D. Osborn🇺🇸

   sPHENIX is a next-generation experiment at RHIC for jet and heavy-flavor physics which was fully commissioned during 2023 and 2024. Using its novel streaming-readout-capable, precision tracking system, sPHENIX collected 100 billion unbiased $p$$+$$p$ collisions, and a further sample of minimum-bias Au-Au collisions, in Run-24. A key measurement of the sPHENIX heavy flavor physics program is the comparison of ${\Lambda }_c^{+}$ to $D^0$ differential yields in both Au+Au and $p$$+$$p$ collisions, which probes questions related to the hadronization of heavy-flavor baryons compared to mesons in the Quark-Gluon Plasma medium and in vacuum. At RHIC energies, there is no previous measurement of the ${\Lambda }_c^{+}/D^0$ baseline in $p$$+$$p$ collisions, modern Monte Carlo event generators give widely different predictions, and the ratio in Au+Au is only poorly known. These proceedings present the status of measurement from sPHENIX of the ${\Lambda }_c^{+}/D^0$ ratio in $p$$+$$p$ collisions.

   nucl-exhep-exEPJ Web Conf.(2026)·0 citations
2. 02*

   $A_{\beta }[E_{\beta }]$ in ${}^{37}$K decay: new physics with opposite $\beta$ helicity

   Melissa Anholm🇨🇦 · J.A. Behr🇨🇦 · D.G. Melconian🇺🇸 · G. Gwinner🇨🇦 · A. Gorelov🇨🇦 · J.C. McNeil🇨🇦 · B. Fenker🇺🇸 · S. Behling🇺🇸

   By extending our analysis and simulations of our ${}^{37}$K $\beta$-decay data set to allow the $\beta$ asymmetry with respect to nuclear spin to vary with $\beta$ energy $E_{\beta }$, we have gained sensitivity to new physics that depends on a helicity factor for the $\beta$, $m_{\beta }/E_{\beta }$. In particular, we constrain Lorentz scalar and tensor quark-lepton interaction strengths at a sensitivity complementary to the similar Fierz interference term in neutron $\beta$ decay. Our result for that new physics is a Fierz interference term $b$ = 0.033 $\pm$ 0.084 (stat) $\pm$ 0.039 (syst), consistent with the standard model electroweak interaction value $b=0$. We consider presently achieved complementarity to $\beta$-decay and particle physics experiments, along with projectable technical improvements to our method.

   nucl-exhep-phnucl-thPRC(2026)·0 citations
3. 03*

   High-Precision Measurement of D($\gamma$, $n$)$p$ Photodisintegration Reaction and Implications for Big-Bang Nucleosynthesis

   Yinji Chen🇨🇳 · Zirui Hao🇨🇳 · Jianjun He🇨🇳 · Toshitaka Kajino🇨🇳 · Shung-ichi Ando🇰🇷 · Yudong Luo🇨🇳 · Hongrui Feng🇨🇳 · Liyong Zhang🇨🇳 · Gongtao Fan🇨🇳 · Hongwei Wang🇨🇳 · Hao Zhang🇨🇳 · Zhilin Shen🇨🇳 and 10 other authors

   We report on a high-precision measurement of the D($\gamma$,\,$n$)$p$ photodisintegration reaction at the newly commissioned Shanghai Laser Electron Gamma Source (SLEGS), employing a quasi-monochromatic $\gamma$-ray beam from Laser Compton Scattering. The cross sections were determined over $E_{\gamma }$=2.327--7.089 MeV, achieving up to a factor of 2.2 improvement in precision near the neutron separation threshold. Combined with previous data in a global Markov chain Monte Carlo (MCMC) analysis using dibaryon effective field theory, we obtained the unprecedentedly precise $p$($n$,\,$\gamma$)D cross sections and thermonuclear rate, with a precision up to $\approx$4 times higher than previous evaluations. Implemented in a standard Big-Bang Nucleosynthesis (BBN) framework, this new rate decreases uncertainty of the key cosmological parameter of baryon density ${\Omega }_b{h}^2$ by up to $\approx$16\% relative to the LUNA result. A residual $\approx$1.2$\sigma$ tension between ${\Omega }_b{h}^2$ constrained from primordial D/H observations and CMB measurements persists, highlighting the need for improved $dd$ reaction rates and offering potential hints of new physics beyond the standard model of cosmology.

   nucl-exastro-ph.COastro-ph.IMPRL(2026)·7 citations
4. 04*

   New probes of nuclear gluon dynamics through photoproduction of charm in inelastic ultra-peripheral Pb$—$Pb collisions with ALICE

   Sigurd Nese (for the ALICE Collaboration)🇳🇴

   In an ultra-peripheral collision, a photon can interact with a gluon in the target nucleus and produce a pair of charm quarks, while the target nucleus breaks up (inelastic scattering). These charm quarks then fragment and are observed as open charm hadrons or vector mesons. This process has been used in e$—$p collisions to set stringent limits on the proton gluon distribution at low-$x$. The current measurements can provide similar constraints on the much less known nuclear gluon distributions. ALICE has measured the transverse momentum distribution of inelastically photoproduced ${\text{D}}^0$ at midrapidity, in Pb$—$Pb collisions at $\sqrt{s_{\text{NN}}}$=5.36 TeV. The distribution is measured down to $p_{\text{T}}$=0 for the first time. The results are compared to model calculations.

   nucl-exhep-exEPJ Web Conf.(2026)·6 citations
5. 05*

   Glauber quark and gluon contributions to quark energy loss at next-to-leading order and next-to-leading twist

   Amit Kumar🇨🇦 · Gojko Vujanovic🇨🇦

   The higher-twist formalism is used at $O({\alpha }_s^2)$ to compute all possible medium-induced single-scattering emission kernels for an incoming highly energetic and virtual quark traversing the nuclear environment. The effects of the heavy-quark mass scale are taken into account [Phys. Rev. C 94, 054902 (2016)] both in the initial state as well as in the final state, along with interactions involving both in-medium Glauber gluons and quarks [Nucl. Phys. A 793, 128 (2007)], as well as coherence effects [Phys. Rev. C 105, 024908 (2022)]. As this study is a continuation of our work on medium-induced photon production [Phys. Rev. C 112, 025204 (2025)], the general factorization procedure for $e$-$A$ deep-inelastic scattering is still used. An incoming quark energy loss in the nuclear medium yields four possible scattering kernels $K_i$ with the following final states: (i) $q+g$, (ii) $g+g$, (iii) $q+{\bar{q}}^{\prime }$, where the quark $q$ may have a flavor different from the antiquark ${\bar{q}}^{\prime }$, and (iv) $q+q^{\prime }$, where, again, $q$ may have a flavor different from $q^{\prime }$. The collisional kernels include full phase factors from all non-vanishing diagrams and complete first-order derivative in the longitudinal direction ($k^{-}$) as well as second-order derivative in the transverse momentum ($k_{\perp }$) gradient expansion. Furthermore, in-medium parton distribution functions and the related jet transport coefficients have a hard transverse-momentum dependence (of the emitted quark or gluon) present within the phase factor.

   ↳ hep-phnucl-exnucl-thPRC(2026)·4 citations
6. 06*

   Nuclear transitions on demand

   C.-J. Yang🇷🇴

   I show a way to tune photo-nuclear cross section effectively and therefore achieve nuclear transitions "on demand". The method is based on combinatorial enhancement of multiphoton processes under intense conditions. Taking advantage of recent advances in high-power laser systems (HPLS) and nuclear structure calculations, efficient control of nuclear transitions up to E4 in multipolarity can be reached today. The same idea can be extended to the search for rare transitions and hidden states, which applies to the $\gamma$-beams generated from conventional sources as well.

   ↳ nucl-thnucl-exEPJ Web Conf.(2025)·0 citations
7. 07*

   Nuclear Beavers

   Joshua Wylie · Pablo Giuliani🇺🇸 · Kyle Godbey🇺🇸 · Sylvester Agbemava

   Nuclear physics is a very abstract field with little accessibility for wider audiences, and yet it is a field of physics with far reaching implications for everyday life. The Nuclear Beavers demonstration is a hands-on experience that offers an intuitive lens into nuclear structure and decay. We aim to provide a more accessible entry point for students and educators by substituting complex nuclear structures and interactions with tactile building blocks following well-defined rules, thereby opening nuclear physics concepts to the general public.

   ↳ physics.ed-phnucl-exnucl-th0 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.