Mon·Apr 21, 2025Monday·April 21, 2025

1. 01*

   The $\beta$-decay spectrum of Tritiated graphene: combining nuclear quantum mechanics with Density Functional Theory

   Andrea Casale🇺🇸 · Angelo Esposito🇮🇹 · Guido Menichetti🇮🇹 · Valentina Tozzini🇮🇹

   We present the results of a multi-methodological study aimed at investigating the interaction between graphene and Tritium during its $\beta$-decay to Helium, under different levels of loading and geometrical configurations. We combine Density Functional Theory (DFT), to evaluate the interaction potentials, with calculations of the decay rate, in order to study the consequences that the presence of the substrate has on the $\beta$-decay spectrum of Tritium. We determine the shape of the event rate, accounting for the effects of (part of) the corresponding condensed matter degrees of freedom. In the context of future neutrino experiments, our results provide important information aimed at the optimization of hosting material, as well as the determination of the physics reach. Furthermore, our work outlines a novel theoretical and computational scheme to address a question at the boundary between high and low energy physics. This requires non-conventional declinations of DFT combined with full quantum treatments of the nuclear configuration involved in the decay process.

   hep-phcond-mat.mes-hallPRC(2026)·8 citations
2. 02*

   Generalized Parton Distributions from Symbolic Regression

   Andrew Dotson🇺🇸 · Zaki Panjsheeri🇺🇸 · Anusha Reddy Singireddy🇺🇸 · Douglas Q. Adams🇺🇸 · Emmanuel Ortiz-Pacheco🇸🇮 · Marija Cuic🇺🇸 · Yaohang Li🇺🇸 · Huey-Wen Lin🇺🇸 · Simonetta Liuti🇺🇸 · Matthew D. Sievert🇺🇸 · Marie Boer🇺🇸 · Gia-Wei Chern🇺🇸 · Michael Engelhardt🇺🇸 · Gary R. Goldstein🇺🇸

   AI/ML informed Symbolic Regression is the next stage of scientific modeling. We utilize a highly customizable symbolic regression package ``PySR" to model the $x$ and $t$ dependence of the flavor isovector combination $H_{u-d}(x,t,\xi )$ at $\xi =0$. These PySR models were trained on GPD results provided by both Lattice QCD and phenomenological sources GGL, GK, and VGG. We demonstrate, for the first time, the consistency and systematic convergence of Symbolic Regression by quantifying the disparate models through their Taylor expansion coefficients. In addition to PySR penalizing models with higher complexity and mean-squared error, we implement schemes that test specific physics hypotheses, including force-factorized $x$ and $t$ dependence and Regge behavior in PySR GPDs. We show that PySR can identify factorizing GPD sources based on their response to the Force-Factorized model. Knowing the precise behavior of the GPDs, and their uncertainties in a wide range in $x$ and $t$, crucially impacts our ability to concretely and quantitatively predict hadronic spatial distributions and their derived quantities.

   hep-phhep-lat14 citations
3. 03*

   Heavy quark mass effects in charged-current deep-inelastic scattering at approximate NNLO in the Aivazis-Collins-Olness-Tung scheme

   Peter Risse🇩🇪 · Valerio Bertone🇫🇷 · Tomas Ježo🇩🇪 · Karol Kovařík🇩🇪 · Aleksander Kusina🇵🇱 · Fredrick Olness🇺🇸 · Ingo Schienbein🇫🇷

   The approximate SACOT-$\chi$ scheme for heavy quark production in deep-inelastic scattering was initially formulated for the neutral current structure functions $F_2$ and $F_L$. We extend this approach to the charged current case (also including $F_3$), and thereby complete the definitions for the most relevant inclusive structure functions. Furthermore, we implement these structure functions in the open-source code $\text{APFEL++}$ which provides fast numerical evaluations over a wide kinematic range; this addition to the $\text{APFEL++}$ code is publicly available, with details provided in the appendix. This SACOT-$\chi$ implementation enables, for the first time, detailed numerical insights on the mass dependence of the structure functions and cross sections in the $(x,Q^2)$-plane for both neutral and charged current processes. We consider kinematic regions relevant for the experimental measurements from fixed-target $\nu$DIS experiments (NuTeV, CCFR and Chorus) and HERA, and also projections for the upcoming EIC. In particular, the $\nu$DIS experiments reveal a surprisingly strong dependence on the mass effects, offering valuable insights that may help resolve long-standing challenges in accurately describing these datasets.

   hep-phPRD(2025)·10 citations
4. 04*

   Connecting Pre-Thermal and Hydrodynamizing Attractors With Adiabatic Hydrodynamization

   Krishna Rajagopal🇺🇸 · Bruno Scheihing-Hitschfeld🇺🇸 · Rachel Steinhorst🇺🇸

   The far-from equilibrium dynamics of the pre-hydrodynamic quark-gluon plasma (QGP) formed in heavy ion collisions can be characterized by distinct stages, during each of which the system loses some memory of its initial condition, until only the hydrodynamic modes remain. However, even though it has been repeatedly observed, finding intuitive physical explanations of how and why attractor behavior occurs has remained a challenge. The Adiabatic Hydrodynamization (AH) framework provides exactly such an explanation, showing that the attractor solution can be thought of as the ground state of an analog to quantum mechanical adiabatic evolution, provided we identify appropriate coordinate rescalings. Using the example of a simplified QCD kinetic theory in the small-angle scattering limit, we show how AH can explain both the early pre-hydrodynamic attractor and the later hydrodynamizing attractor in a longitudinally expanding gluon gas in a unified framework. By doing this, we provide a unified description of, and intuition for, all the stages of what in QCD would be bottom-up thermalization, starting from a pre-hydrodynamic attractor and ending with hydrodynamization.

   hep-phEPJ Web Conf.(2025)·0 citations
5. 05*

   Particle physics: a personal view

   Goran Senjanović🇩🇪

   The reader surely knows what particles physics is about: finding building blocks of nature that appear elementary at a given time and study their interactions - so why in the world this essay? The problem is how to arrive at a fundamental theory, and maybe even more important, what is the theory supposed to do? I follow here a simple but profound prescription of Feynman for a true, self-contained theory, and then show how the Standard Model beautifully illustrates this prescription. That the issue is not trivial, is clear from the fact that we had theories dominate our field for decades, in spite of completely failing Feynman's requirements and offering no clear predictions whatsoever. I next critically review two unique candidates for a Beyond Standard Model theory: the Left-Right Symmetric theory of electro-weak interactions and the minimal grand unified theory based on SU(5) gauge symmetry. I also comment on some generic aspects of grand unification, and what hope we may have in testing it.

   hep-phhep-exhep-thMod.Phys.Lett.A(2025)·0 citations
6. 06*

   An analysis on doubly bottom molecular tetraquarks composed of $H_{(s)}$ and $T_{(s)}$ doublets

   Jun-Chao Su🇨🇳 · Qing-Fu Song🇨🇳 · Qi-Fang Lü🇨🇳 · Jingya Zhu🇨🇳

   In this work, we investigate the doubly bottom $H_{(s)}{\bar{T}}_{(s)}$ and $H_{(s)}{T}_{(s)}$ systems by adopting the one-boson-exchange model, where $H_{(s)}$ and $T_{(s)}$ represent $S$-wave $B_{(s)}^{(\ast )}$ and $P$-wave $B_{(s)1,2}^{(\ast )}$ doublets, respectively. For the $H\bar{T}$ systems, we predict some loosely bound states in the $I(J^{PC})=0(1^{-\pm })$ $B{\bar{B}}_1$, $I(J^{PC})=0(2^{-\pm })$ $B{\bar{B}}_2^{\ast }$, $I(J^{PC})=0(1^{-\pm })$ $B^{\ast }{\bar{B}}_1$ and $I(J^{PC})=0(2^{-\pm })$ $B^{\ast }{\bar{B}}_2^{\ast }$ channels, which are the most promising hidden bottom molecular tetraquarks. For the $HT$ systems, the $B^{\ast }{B}_1$ channels with quantum numbers $I(J^P)=0(1^{-}),0(2^{-})$ and the $B^{\ast }{B}_2^{\ast }$ channels with $I(J^P)=0(2^{-})$ are also likely candidates for forming molecular tetraquarks. In contrast, no molecular candidates have been identified in the bottom-strange sectors. One can hope that our predictions will provide valuable insights to the LHCb and Belle II Collaborations as they continue to explore this fascinating field through experimental research.

   hep-phEPJC(2025)·2 citations
7. 07*

   Unveiling the electromagnetic structure and intrinsic dynamics of spin-$\frac{3}{2}$ hidden-charm pentaquarks: A comprehensive QCD analysis

   U. Özdem🇹🇷

   In this study, we investigate the electromagnetic properties$-$ specifically, the magnetic dipole, electric quadrupole, and magnetic octupole moments$-$ of six hidden-charm pentaquark states: $[uu][dc]\bar{c}$, $[dd][uc]\bar{c}$, $[uu][sc]\bar{c}$, $[dd][sc]\bar{c}$, $[ss][uc]\bar{c}$, and $[ss][dc]\bar{c}$. Employing the framework of QCD light-cone sum rules and utilizing two distinct diquark-diquark-antiquark interpolating currents, we focus on pentaquark configurations with spin-parity quantum numbers ${\mathrm{J}}^{\mathrm{P}}={\frac{3}{2}}^{-}$. From the numerical results, we observe significant deviations between the magnetic dipole moment predictions obtained using different diquark-diquark-antidiquark structures. These results suggest that multiple pentaquark states with identical quantum numbers and quark constituents may exhibit distinct magnetic dipole moments, depending on their internal quark configurations. The obtained electromagnetic moments, particularly the variations in magnetic dipole moments, may provide insights into the internal structure of hidden-charm pentaquark states.

   hep-phhep-exhep-latCPC(2025)·8 citations
8. 08*

   Q-balls Under Spontaneously Broken U(1) Symmetry

   Masahiro Kawasaki🇯🇵 · Kai Murai🇯🇵 · Fuminobu Takahashi🇯🇵

   We study the evolution of Q-balls under a spontaneously broken global $U(1)$ symmetry. Q-balls are stabilized by the conservation of $U(1)$ charge, but when the symmetry is spontaneously broken, the resulting Nambu-Goldstone (NG) boson can carry charge away from the Q-ball, potentially leading to charge leakage. To study this process in a controlled setting, we consider a scenario where Q-balls first form under an unbroken $U(1)$ symmetry, which is then spontaneously broken. We introduce two complex scalar fields: one responsible for forming the Q-ball, and the other for spontaneously breaking the $U(1)$ symmetry, allowing us to clearly separate the formation and symmetry-breaking phases. Using numerical simulations in a spherically symmetric system, we find that the evolution of Q-balls depends sensitively on the structure of the interaction between the two fields and the magnitude of symmetry breaking. Depending on parameters, Q-balls can completely decay, evaporate into smaller, stable Q-balls, or transition into oscillons/I-balls. In particular, we find that stable, localized remnants often survive the evolution over long timescales, especially when the symmetry-breaking scale is small. These results demonstrate that, even though spontaneous $U(1)$ breaking can lead to significant energy and charge loss from Q-balls, stable localized objects with reduced or no charge can frequently survive and potentially contribute to cosmological relics.

   hep-phastro-ph.COPRD(2025)·4 citations
9. 09*

   Decay rate of PQ-ball

   Jin Kobayashi🇯🇵 · Kazunori Nakayama🇯🇵 · Masaki Yamada🇯🇵

   Q-balls are non-topological solitons that arise in theories with a complex scalar field possessing a conserved global U(1) charge. Their stability is ensured by this charge, making them potentially significant in cosmology. In this paper, we investigate Q-ball-like objects in scenarios where the scalar field acquires a finite vacuum expectation value, spontaneously breaking the global U(1) symmetry. A well-motivated example is the Peccei-Quinn field, where the U(1) symmetry is identified as the Peccei-Quinn symmetry, and hence we refer to such objects as PQ-balls. We first discuss the existence of stable PQ-ball solutions in a finite-density plasma and argue that they become unstable in vacuum. Using detailed numerical simulations under spherical symmetry, we confirm their formation, compute their decay rate, and derive an analytical formula for it. Our results have important implications for axion cosmology, particularly in the context of the kinetic misalignment mechanism.

   hep-phastro-ph.COJCAP(2025)·3 citations
10. 10*

    Towards automatizing Higgs decays in BSM models at one-loop in the decoupling renormalization scheme

    Jonas Lang🇵🇱 · Wojciech Kotlarski🇵🇱

    We propose the use of a decoupling renormalization scheme in the calculation of NLO corrections to SM-like Higgs boson decays in the beyond the Standard Model models. The advantage of this particular scheme is its decoupling property in the presence of a heavy BSM physics and the possibility to directly include known higher-order Standard Model corrections. We illustrate the use of this scheme by analysing the $h\to {\mu }^{+}{\mu }^{-}$ decay in a simple Standard Model extension by an $S_1$ leptoquark.

    hep-phActa Phys.Polon.Supp.(2025)·1 citation
11. 11*

    The light-by-light contribution to the muon g-2 within the nonlocal chiral quark model with vector and axial-vector mesons

    A.E. Radzhabov🇷🇺 · A.S. Zhevlakov🇷🇺

    The hadronic light-by-light contribution to the muon anomalous magnetic moment is calculated in the framework of a nonlocal quark model with scalar-pseudoscalar and vector-axial-vector channels. The effect of the dressing of internal photons by vector mesons is found to be tiny. As a result, the contribution from the non-strange quark loop is a_{\mu}^{HLbL,Loop}=( 96+-15.4)x10^{-11}. The total value, including meson exchanges and the contribution of strange particles, is a_{\mu}^{HLbL}=( 157+-10.6)x10^{-11}.

    hep-phPRD(2025)·2 citations
12. 12*

    Twist-3 generalized parton distributions of sea quarks at zero skewness in the light-cone quark model

    Xiaoyan Luan🇨🇳 · Zhun Lu🇨🇳

    We present a systematic study of twist-3 generalized parton distributions (GPDs) for $\bar{u}$ and $\bar{d}$ sea quarks in the proton at zero skewness ($\xi =0$) using the light-cone formalism with overlap representation. The proton wave functions are derived from a meson-baryon fluctuation model that incorporates $|q\bar{q}B⟩$ Fock states, providing a natural framework for investigating sea quark contributions. Within this approach, we compute the complete set of twist-3 GPDs and present the numerical results, including both chiral-odd ($H_2$, $E_2$, ${\tilde{E}}_2$, ${\tilde{H}}_2^{\prime }$) and chiral-even (${\tilde{E}}_{2T}$, $H_{2T}^{\prime }$, $E_{2T}^{\prime }$, ${\tilde{H}}_{2T}^{\prime }$) distributions for $\bar{u}$ and $\bar{d}$ quarks at zero skewness. By taking the forward limit, we also calculate the corresponding twist-3 parton distribution functions $e(x)$ of $\bar{u}$ and $\bar{d}$ quarks. The kinetic orbital angular momenta of sea quarks deduced from the twist-3 GPDs are studied and compared to those from the twist-2 GPDs.

    hep-phPRD(2025)·2 citations
13. 13*

    Next-to-leading-order QCD calculations of $B\to A$ form factors with higher-twist corrections

    Fang-Zhou Di🇨🇳 · Yu-Hao Liu🇨🇳

    Applying the light-cone sum rules (LCSR) approach, the next-to-leading-order (NLO) corrections to $B\to A$ form factors are calculated with the twist-two and twist-three $B$ meson light-cone distribution amplitudes (LCDAs) at leading power in $\Lambda /m_b$. At one-loop level, the vacuum-to-$B$-meson correlation functions defined with interpolating currents for the $p$-wave axial-vector meson are factorized into short-distance coefficients and the distribution amplitudes (DAs) of the $B$ meson, among which the hard coefficients for A0-type currents and $\mu$ dependent jet functions entering correlation functions ${\Pi }_{\mu ,\Vert }^{(T+\tilde{T})}$, ${\Pi }_{\delta \mu ,\perp }^{(V-A)}$ and ${\Pi }_{\delta \mu ,\perp }^{(T+\tilde{T})}$ are identical to the corresponding ones of $B\to V$ in SCET. In addition, ${\Pi }_{\mu ,\Vert }^{(V-A)}$ and ${\Pi }_{\mu ,\Vert }^{(T+\tilde{T})}$ coincide with the results of $B\to \pi ,K$ under the limit $m_q\to 0$ up to one-loop accuracy. Then the subleading power corrections to $B\to A$ form factors are computed with the higher-twist $B$ meson LCDAs at tree level up to the twist-six accuracy. Furthermore, we predict the $q^2$ dependence of $B\to A$ form factors via the Bourrely-Caprini-Lellouch (BCL) $z$-series expanding parameterization to compute several physical observables including branching ratios of semileptonic $B\to A\ell {\bar{\nu }}_{\ell }$ and $B\to A{\nu }_{\ell }{\bar{\nu }}_{\ell }$ processes, transverse asymmetries, forward-backward asymmetries and lepton flavor universality observables employing the given mixing angles ${\theta }_K=-34^{\circ }$, ${\theta }_{1_{P_1}}=28^{\circ }$, ${\theta }_{3_{P_1}}=23^{\circ }$. We also compare our theory calculations with the results from other methods.

    hep-phPRD(2025)·3 citations
14. 14*

    The experimental observation of $a_0(1710)$: Long awaited from Regge approach

    S. S. Afonin🇷🇺

    Recently, the BABAR (in 2021), BESIII (in 2022), and LHCb (in 2023) Collaborations reported the observation of the $a_0(1710)$ resonance. This has sparked a lively debate in the literature about the nature of this possible isospin partner of $f_0(1710)$, since the latter has long been regarded as the main candidate for the lightest glueball. We highlight the clear prediction of $a_0(1710)$ in 2007 within the Regge approach using the observed hydrogen-like degeneracy in the spectrum of light mesons. Our reanalysis of the data used shows that the prediction was reliable and thus indicates that $a_0(1710)$ and $f_0(1710)$ are conventional quark-antiquark states.

    hep-phPhys.Atom.Nucl.(2025)·2 citations
15. 15*

    Bubble wall velocity from Kadanoff-Baym equations: fluid dynamics and microscopic interactions

    Michael J. Ramsey-Musolf🇨🇳 · Jiang Zhu🇨🇳

    We establish a first principles, systematic framework for determining the bubble wall velocity during a first order cosmological phase transition. This framework, based on non-local Kadanoff-Baym equations, incorporates both macroscopic fluid dynamics and microscopic interactions between the bubble wall and particles in the plasma. Previous studies have generally focused on one of these two sources of friction pressure that govern the wall velocity. As a precursor, we utilize background field quantum field theory to obtain the relevant local Boltzmann equations, from which we derive the forces associated with variation of particle masses across the bubble wall and the microscopic wall-particle interactions. We subsequently show how these equations emerge from the Kadanoff-Baym framework under various approximations. We apply this framework in the ballistic regime to compute the new friction force arising from the $2\to 2$ scattering processes in scalar field theory. We obtain a linear relationship between this force and the Lorentz factor ${\gamma }_w$ that would preclude runaway bubbles with such effects.

    hep-phhep-th15 citations
16. 16*

    Bubble wall dynamics from nonequilibrium quantum field theory

    Wen-Yuan Ai🇦🇹 · Matthias Carosi🇩🇪 · Bjorn Garbrecht🇩🇪 · Carlos Tamarit🇩🇪 · Miguel Vanvlasselaer🇧🇪

    We derive the coupled dynamics between the bubble wall and the plasma from first principles using nonequilibrium quantum field theory. The commonly used equation of motion of the bubble wall in the kinetic approach is shown to be incomplete. In the language of the two-particle-irreducible effective action, the conventional equation misses higher-loop terms generated by the condensate-particle type vertices (e.g.,~$\phi \varphi {\chi }^2$, where $\phi$ is the background field describing the bubble wall, $\varphi$ the corresponding particle excitation and $\chi$ another particle species in the plasma). From the missing terms, we identify an additional dissipative friction which is contributed by particle production processes from the condensate-particle type vertices. We also show how other transmission processes beyond the 1-to-1 elementary transmission studied in the literature for ultrarelativistic bubble walls, e.g., 1-to-1 mixing and 1-to-2 transition radiation, can be understood from the kinetic approach.

    hep-phastro-ph.COhep-thJHEP(2025)·39 citations
17. 17*

    Expected statistical uncertainties at future $e^{+}{e}^{-}$ colliders

    Hieu Minh Tran🇻🇳 · Sang Quang Dinh🇻🇳 · Trang Quynh Trieu🇻🇳

    In future colliders, the frontiers of luminosity and energy are extended to explore the physics of elementary particles at extremely high precision, and to discover new phenomena suggested from current experimental anomalies. In this letter, we present a simple method to estimate the expected statistical uncertainties of scattering cross sections at future colliders using their conceptual design reports. In particular, the expected statistical uncertainties of muon pair production cross section at the Future Circular Collider (FCC-ee) and the Circular Electron-Positron Collider (CEPC) are calculated. The results can be used to set a goal for systematic uncertainty improvement, to determine the standard model parameters accurately, and to identify the viable parameter space of new physics models.

    hep-phhep-exnucl-exEPL(2025)·1 citation
18. 18*

    Data-based form factor corrections between the two-pion $\tau$ and $e^{+}{e}^{-}$ spectral functions

    Michel Davier🇫🇷 · Bogdan Malaescu🇫🇷 · Zhiqing Zhang🇫🇷

    The $\tau$ spectral functions are an alternative to $e^{+}{e}^{-}$ cross-sections, where different measurements are not consistent, for computing the hadronic vacuum contribution to the muon magnetic anomaly $a_{\mu }$. This requires a control of isospin-breaking effects which have to be corrected for. So far these corrections have been evaluated using theoretical models. In this letter, a new approach based only on data is presented for the determination of the most critical correction relating the $e^{+}{e}^{-}$ and $\tau$ pion form factors. An updated evaluation of the total isospin-breaking correction is given and its impact is discussed in the context of $e^{+}{e}^{-}$-based $a_{\mu }$ predictions and of the direct measurement.

    hep-phhep-ex11 citations
19. 19*

    Extracting the chiral anomaly from $e^{+}{e}^{-}\to 3\pi$

    Martin Hoferichter🇨🇭 · Bai-Long Hoid🇩🇪 · Bastian Kubis🇩🇪

    The strength of the interaction of three pions and a photon, $F_{3\pi }$ is predicted by the axial anomaly in terms of the pion decay constant, a relation that is frequently used to constrain low-energy radiative processes involving pions, but only tested experimentally at the $10\%$ level. Here, we present a new avenue to test this prediction, via a fit of a dispersive description of the ${\gamma }^{\ast }\to 3\pi$ amplitude to data for $e^{+}{e}^{-}\to 3\pi$. From the global fit to SND, CMD-2, and BaBar data we obtain $F_{3\pi }=33.1(1.7){\text{GeV}}^{-3}$, in agreement with the chiral prediction at the level of $5\%$. We also consider dispersive fits to the recent data by Belle II, in which case we observe tensions with the dispersive constraints, the width parameters of $\omega$ and $\varphi$, and the chiral anomaly.

    hep-phhep-exhep-latnucl-thJHEP(2025)·17 citations
20. 20*

    A species scale-driven breakdown of effective field theory in time-dependent string backgrounds

    Alek Bedroya🇺🇸 · Hayden Lee🇺🇸 · Paul Steinhardt🇺🇸

    We present a novel way in which effective field theory (EFT) can break down in cosmological string backgrounds depending on the behavior of the quantum gravity cutoff in infinite distance limits, known as the species scale ${\Lambda }_s$. Namely, EFT can break down if the species scale ${\Lambda }_s$ falls off so rapidly as the Friedmann-Robertson-Walker (FRW) scale factor grows from some initial value $a_i$ to some final value $a_f$ that the physical momentum of an initial Hubble-sized perturbation $\sim H_i^{-1}$ grows to exceed the species scale. For EFT to remain valid, a new condition $H_i\frac{a_i}{a_f}\ll {\Lambda }_{s,f}$ must hold, which is distinct from Trans-Planckian conditions discussed in the literature. Using the universal relation $\frac{\nabla m}{m}\cdot \frac{\nabla {\Lambda }_s}{{\Lambda }_s}=\frac{1}{d-2}$ in the infinite distance limits of moduli space where $m$ is the mass scale of the lightest tower and $\nabla$ measures variations with respect to the canonical metric on moduli space, we show that spatially flat FRW solutions in the string landscape violate this condition or at best marginally satisfy it. However, we find that sufficiently large negative spatial curvature always avoids a breakdown. To avoid EFT breakdown, we derive an upper bound on the duration of quasi-de Sitter expansion that classically evolves to decelerated expansion. Our bound is proportional to the Trans-Planckian Censorship Conjecture (TCC) bound, with the advantage that it applies to any FRW solution in the string landscape. Finally, we distinguish EFT breakdown from TCC violation, the latter being a quantum gravity constraint rather than an EFT limitation. Perhaps our most surprising finding is that in any flat FRW solution that develops a weakly coupled string at future infinity the EFT inevitably breaks down.

    ↳ hep-thastro-ph.COgr-qchep-ph20 citations
21. 21*

    The Unitarity-Limit Expansion for Two Nucleons with Perturbative Pions: Digest and Ideas

    Harald W. Griesshammer (George Washington U.)🇺🇸

    In the Unitarity Limit, the NN S-wave binding energies are zero, the scattering lengths infinite, Physics is universal, i.e. insensitive to details of the interactions, and observables display richer symmetries, namely invariance under both scaling and Wigner's combined SU(4) transformation of spin and isospin. This presentation is a digest of the first quantitative exploration of corrections to this picture when pions are included [1] (see there for a more comprehensive list of references). Since the pion mass and decay constant introduce dimensionful scales in the NN system, they explicitly break the symmetries of the Unitarity fixed point. In $\chi$EFT, these symmetries must therefore be classified as emergent. This text focuses on the $\chi$EFT variant with Perturbative ("KSW") Pions at next-to-next-to leading order (N2LO). This leads to the Hypothesis that both scale invariance and Wigner-SU(4) symmetry in the Unitarity Expansion show persistence, i.e. the footprint of both combined dominates even for $k\gtrsim m_{\pi }$ and is more relevant than chiral symmetry, so that the tensor/Wigner-SU(4) symmetry-breaking part of OPE is suppressed and does not enter before N3LO. Included are also ideas about underlying mechanisms and LO results of $\chi$EFT with Nonperturbative Pions in the expansion about Unitarity.

    ↳ nucl-thhep-phphysics.atom-phPoS(2026)·2 citations
22. 22*

    Productions of ${}_{\Lambda }^3$H, ${}_{\Lambda }^4$H and ${}_{\Lambda }^4$He in different coalescence channels in Au-Au collisions at $\sqrt{s_{NN}}=3$ GeV

    Rui-Qin Wang🇨🇳 · Jun Song🇨🇳 · Mao-Yan Wu🇨🇳 · Huai-Tong Xue🇨🇳 · Feng-Lan Shao🇨🇳

    We study the productions of $\Lambda$-hypernuclei ${}_{\Lambda }^3$H, ${}_{\Lambda }^4$H and ${}_{\Lambda }^4$He in the coalescence mechanism in Au-Au collisions at $\sqrt{s_{NN}}=3$ GeV. Considering the abundance and great importance of baryons and light (hyper-)nuclei on the collision dynamics, we include not only nucleon$+\Lambda$ coalescence but also nucleus+nucleon($\Lambda$) coalescence. We present contributions from different coalescence channels for ${}_{\Lambda }^3$H, ${}_{\Lambda }^4$H and ${}_{\Lambda }^4$He in their productions. We predict the production asymmetry between ${}_{\Lambda }^4$H and ${}_{\Lambda }^4$He, characterized by yield ratios ${}_{\Lambda }^4\text{He}{/}_{\Lambda }^4\text{H}$ and ${(}_{\Lambda }^4\text{H}{-}_{\Lambda }^4\text{He})/{(}_{\Lambda }^4\text{H}{+}_{\Lambda }^4\text{He})$, which can shed light on the existence constraints of the possible neutron-$\Lambda$ bound states ${}_{\Lambda }^{2}n(n\Lambda )$ and ${}_{\Lambda }^{3}n(nn\Lambda )$.

    ↳ nucl-thhep-exhep-phnucl-exPRC(2025)·2 citations
23. 23*

    Evolution of self-gravitating spherical dark-matter halos with and without new physics

    Marc Kamionkowski🇺🇸 · Kris R. Sigurdson🇨🇦

    We present an efficient numerical algorithm for evolving self-gravitating systems of dark-matter particles that leverages the assumption of spherical symmetry to reduce the nominally six-dimensional phase space to three dimensions. It can be used to quickly determine numerically the evolution of an initially static stable self-consistent self-gravitating system if there is some additional or new physics. We illustrate here with four examples: (1) the effects of the growth of a supermassive black hole at the center; (2) the effects of stripping of the outer layers of the halo (a toy model for the effects of tidal stripping of galaxies); (3) the response of a self-gravitating system to dark matter that decays to a slightly less massive state; and (4) the effects of a slow change to Newton's constant. The approach can be extended to study dark matter with elastic and inelastic self-interactions and to study the process of virialization in spherical collapse. We describe some aspects of a code NSphere that implements this approach which we are making available.

    ↳ astro-ph.GAastro-ph.COhep-phhep-thPRD(2026)·3 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.