Mon·Jun 16, 2025Monday·June 16, 2025

1. 01*

   Asymmetric muon-antimuon emission from $Z^0$ decays: a clear magnetometer in relativistic heavy-ion collisions

   Alejandro Ayala🇲🇽 · Ana Julia Mizher🇧🇷 · Javier Rendón🇲🇽

   We show that a very clear signal of the presence of a strong magnetic field during the early stage of a high-energy heavy-ion collision is provided by the decay of the $Z^0$ into dimuon pairs. We find that the process is highly anisotropic, producing pairs mainly out of plane, as signaled by a negative value of $v_2$, and leads to an antimuon transverse momentum distribution which peaks at a higher value of the transverse momentum compared to the peak of the muon transverse momentum distribution. We also show that the process does not produce a significant distortion of the $Z^0$ spectral function. The signal can be identified by comparing the dimuon-invariant mass and the individual muon and antimuon spectra produced in semicentral heavy-ion collisions with the corresponding scaled spectra produced in p+p collisions at the $Z^0$ peak.

   hep-phhep-exnucl-exnucl-thPRC(2026)·3 citations
2. 02*

   Dihadron Angular Correlations in the $e^{+}{e}^{-}$ Collision

   Wan-Li Ju🇨🇦 · Zhe-Yan Shu🇨🇳 · Tong-Zhi Yang🇨🇭 · Zhen-Hua Zhang🇨🇳 · Hua Xing Zhu🇨🇳

   The precision of fixed-order calculations on the dihadron production in electron-positron annihilation is paramount for probing QCD factorization and constraining non-perturbative inputs. This paper investigates the QCD corrections to the angular separation distribution ${\theta }_{12}$ between two observed hadrons, $H_1$ and $H_2$, in the process $e^{+}{e}^{-}\to H_1{H}_2+X$ up to $\mathcal{O}({\alpha }_s^2)$, with particular emphasis on the intermediate region ${\theta }_{12}\in (0,\pi )$. The partonic processes at this accuracy consist of two sorts of contributions, the real-virtual and double-real corrections. Of them, the evaluation of four-body phase space integrals in the latter case is at the core of this study. To address them, we first employ the integration-by-parts (IBP) identities to reduce the number of independent integrals and then apply the differential equations (DE) method to recursively solve the resulting master integrals. In kinematic regions where the invariant mass of the unresolved partons vanishes, IBP coefficients can develop divergences. To this end, we resum higher-order terms in the dimensional regulator for each master integral based on the asymptotic behavior of the canonical DEs. After combining the real and virtual corrections with the counter terms from fragmentation function renormalization, we demonstrate that the pole terms in the final analytic expressions exactly cancel out in all partonic channels, thereby providing a non-trivial validation of collinear factorization at the next-to-leading order (NLO). Eventually, when presenting our analytic expressions of the finite partonic coefficients, we transform the transcendental functions resulting from the DE solutions into classical (poly)logarithmic functions, in order to facilitate the implementation in event generators.

   hep-phJHEP(2025)·2 citations
3. 03*

   Fermion masses and mixings in supersymmetric SO(10) with third-generation quasi-Yukawa unification

   Shaikh Saad🇸🇮 · Qaisar Shafi🇺🇸

   We discuss the charged and neutral fermion masses and mixings in a supersymmetric SO(10) model with a minimal Higgs sector consisting of the multiplets $10_H$, $45_H$, and $16_H+{\overline{16}}_H$. In addition to the renormalizable Yukawa couplings involving the Higgs 10-plet, we include non-renormalizable Yukawa couplings, which are important for reproducing with good accuracy the observed masses and mixings in the quark and lepton sectors. We identify a preferred solution which is compatible with third family quasi-Yukawa unification, namely $y_t\approx y_b\approx 0.73y_{\tau }$ at the unification scale, with the MSSM parameter $\tan \beta \sim 58$. Acceptable solutions with lower $\tan \beta$ values are also realized in our framework, and we provide an example with $\tan \beta =10$. Based on our fits, the masses for the three right-handed neutrinos turn out to be $\left(M_1,M_2,M_3\right)\sim \left(10^9,8\cdot 10^{12},9\cdot 10^{12}\right)\mathrm{GeV}$. We briefly discuss the metastable and quasistable string scenarios that can be realized in this class of supersymmetric SO(10) models.

   hep-phJHEP(2025)·3 citations
4. 04*

   Acoustically driven dark matter freeze-out

   Iason Baldes🇫🇷 · Ryusuke Jinno🇯🇵

   We extend the study of the effect of density perturbations to the well known thermal dark matter freeze-out scenario. We find $\sim 10\%$ enhancements in the cross section are required to match onto the observed relic abundance for primordial curvature perturbations $\sim 0.2$ at length scales $\sim 1/$Hubble at freeze-out. Such corrections may be of importance in scenarios in which such perturbations are present and observational signals, such as the indirect detection rate, depend sensitively on the DM mass and freeze-out cross section, e.g. near resonances associated with DM bound states.

   hep-phastro-ph.COgr-qc0 citations
5. 05*

   CP-violation in production of heavy neutrinos from bubble collisions

   Martina Cataldi🇩🇪 · Kristjan Müürsepp🇮🇹 · Miguel Vanvlasselaer🇧🇪

   First order phase transitions (FOPT) in the early Universe can be powerful emitters of both relativistic and heavy particles, upon the collision of ultra-relativistic bubble shells. If the particles coupling to the bubble wall have CP-violating interactions, the same collision process can also create a local lepton or baryon charge. This CP-violation can originate from different channels, which have only been partially addressed in the literature. We present a systematic analysis of the different channels inducing CP-violation during bubble collisions: 1) the decay of heavy particles 2) the production of heavy particles and 3) the production of light and relativistic Standard Model (SM) particles. As an illustration of the impact that such mechanisms can have on baryon number and dark matter (DM) abundance, we then introduce a simple model of cogenesis, separating a positive and a negative lepton number in the SM and a dark sector (DS). The lepton number asymmetry in the SM can be used to explain the baryon asymmetry of the Universe (BAU), while the opposite asymmetry in the DS is responsible for determining the abundance of DM. Moreover, the masses of light neutrinos can be understood via the inverse seesaw mechanism, with the lepton-violating Majorana mass originating from the FOPT. A typical signal produced by a FOPT is the irreducible gravitational wave (GW) background. We find that a substantial portion of the parameter space can be probed at future observatories like the Einstein Telescope (ET).

   hep-phJHEP(2026)·13 citations
6. 06*

   Gravitational Waves from Spectator Scalar Fields

   Marcos A. G. Garcia🇲🇽 · Sarunas Verner🇺🇸

   We propose a novel mechanism for gravitational wave (GW) production sourced by spectator scalar fields during inflation. These fields, while not driving cosmic expansion, generate blue-tilted isocurvature fluctuations that naturally satisfy current CMB constraints at large scales while producing enhanced power spectra at smaller scales accessible to GW detectors. The resulting GW spectrum spans an exceptionally broad frequency range from $10^{-20}$ to $1$ Hz, with amplitudes ranging from ${\Omega }_{\text{GW}}{h}^2\sim 10^{-20}$ to $10^{-12}$ depending on the reheating temperature and spectator field mass. For heavy spectator fields with effective masses near the inflationary Hubble scale $H_I$, the mechanism produces observable signals across multiple detector bands accessible to pulsar timing arrays, space-based interferometers, and ground-based detectors. Our analysis reveals multiple complementary constraints on spectator field parameters. GW-induced limits on the effective number of relativistic species ($\Delta N_{\text{eff}}$) require $m_{\chi }\gtrsim 0.61H_I$, stronger than CMB isocurvature bounds alone ($m_{\chi }\gtrsim 0.54H_I$). The non-observation of primordial B-modes by \textit{Planck} provides stronger constraints $m_{\chi }\gtrsim 0.66H_I$, with projected LiteBIRD sensitivity potentially reaching $m_{\chi }\gtrsim 0.70H_I$. This mechanism enables a unique multi-messenger probe of beyond the Standard Model physics during inflation, providing simultaneous constraints on inflationary dynamics, dark matter production, and reheating through current and next-generation GW experiments.

   hep-phastro-ph.COgr-qcPRD(2026)·10 citations
7. 07*

   Extremal Magic States from Symmetric Lattices

   Misaki Ohta🇵🇱 · Kazuki Sakurai🇵🇱

   Magic, a key quantum resource beyond entanglement, remains poorly understood in terms of its structure and classification. In this paper, we demonstrate a striking connection between high-dimensional symmetric lattices and quantum magic states. By mapping vectors from the $E_8,B{W}_{16}$, and $E_6$ lattices into Hilbert space, we construct and classify stabiliser and maximal magic states for two-qubit, three-qubit and one-qutrit systems. In particular, this geometric approach gives closed-form lattice representatives of maximal magic states and motivates a conjecture for the number of three-qubit maximal states. In the three-qubit case, we further classify the extremal magic states according to their entanglement structure. We also show that the 45 one-qutrit maximal magic states selected by the second shell of $E_6$ split into two Clifford orbits. Our findings suggest that deep algebraic and geometric symmetries underlie the structure of extremal magic states.

   ↳ quant-phhep-phhep-thmath-ph+16 citations
8. 08*

   InflationEasy: A C++ Lattice Code for Inflation

   Angelo Caravano🇫🇷

   InflationEasy is a lattice code specifically developed for cosmological inflation. It simulates the nonlinear dynamics of a scalar field on a three-dimensional lattice in an expanding FLRW universe using finite-difference spatial derivatives. Based in part on the well-known LATTICEEASY, it incorporates several features tailored specifically to inflationary applications, including a nonperturbative $\delta N$ method to compute the curvature perturbation at the end of inflation $\zeta$ directly from the lattice. In addition to the scalar sector, the code can also simulate scalar-induced gravitational waves, accounting for contributions generated both during inflation and during the subsequent horizon re-entry of scalar perturbations, and enabling the computation of the resulting gravitational-wave background. \texttt{InflationEasy} enables fully nonlinear studies of regimes with large fluctuations or nonperturbative non-Gaussianities, which lie beyond the reach of standard perturbation theory. It is applicable to a broad range of inflationary models, including those relevant for primordial black hole formation, gravitational-wave backgrounds, and large-scale structure.

   ↳ astro-ph.COgr-qchep-lathep-ph10 citations
9. 09*

   Binary systems as gravitational wave detectors

   Diego Blas🇪🇸 · Adrien Bourgoin🇫🇷 · Joshua F. Foster🇺🇸 · Aurelien Hees🇫🇷 · Miriam Herrero-Valea🇪🇸 · Alexander C. Jenkins🇩🇪 · Xiao Xue🇪🇸

   ``Adding colour'' to the gravitational-wave sky by probing unexplored frequency bands has the potential to unveil new and unexpected phenomena in the Universe. In these proceedings, we summarise current efforts to probe gravitational waves with $\mu$Hz frequencies through their resonant impact on binary systems. We also discuss how these binaries can explore uncharted regions of parameter space in the hunt for dark matter.

   ↳ gr-qchep-ph1 citation
10. 10*

    On the Gravitational Origin of the QCD Axion

    Georgios K. Karananas🇩🇪 · Mikhail Shaposhnikov🇨🇭 · Sebastian Zell🇩🇪

    Gravity can give rise to (pseudo)scalar fields, for instance due to torsion. In particular, axions of gravitational origin have been proposed as a minimal and compelling solution to the strong CP problem. In this work, we critically examine the feasibility of this approach. We demonstrate that models in which the scalar field couples to fermionic currents only through derivatives do not yield a satisfactory axion. Moreover, we identify the necessary conditions for generating a gravitational axion through quantum effects, highlighting Weyl-invariant Einstein-Cartan gravity as a promising theoretical setting.

    ↳ hep-thgr-qchep-phPRL(2025)·12 citations
11. 11*

    Progress in Einstein-Cartan gravity

    Mikhail Shaposhnikov🇨🇭

    It is well-known that the gravitational force can be obtained by gauging the Lorentz group, which puts gravity on the same footing as the Standard Model fields. The resulting theory - Einstein-Cartan gravity - has several crucial advantages. I will overview the construction of the Weyl-invariant version of this theory and discuss its applications in particle physics and cosmology, in particular for inflation and the strong CP problem.

    ↳ hep-thgr-qchep-ph7 citations
12. 12*

    On the prospects of thermalization of axion-SU(2) inflation

    Sukannya Bhattacharya🇪🇸 · Matteo Fasiello🇪🇸 · Alexandros Papageorgiou🇪🇸 · Ema Dimastrogiovanni🇳🇱

    Axion inflation models coupled to a gauge sector via a Chern-Simons term exhibit an array of interesting phenomenology including a chiral gravitational wave spectrum and primordial black hole production. They may also provide a useful mechanism for generating lepton asymmetry. The possibility to embed this class of models in UV-finite theories and their intriguing, testable, signatures make for a compelling candidate for early acceleration. Due to the Chern-Simons coupling, gauge modes may undergo a finite tachyonic growth during which non-linearities become important. Naturally, this raises the question of whether such (self) interactions can lead to thermalization during inflation. We provide a set of useful criteria for sustained thermalization in an axion-$SU(2)$ model and chart the parameter space of the model accordingly. We find that the cold inflation regime constitutes a very significant fraction of the parameter space. Our analysis accounts for a initially vanishing as well as non-zero gauge field vacuum expectation value (VEV). We also consider the possibility of a dynamically generated VEV.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2025)·4 citations
13. 13*

    Impact of particle production mechanisms on pseudorapidity distribution and directed flow in Au+Au and Cu+Cu collisions at $\sqrt{s_{NN}}$ = 19.6 GeV using AMPT model

    Muhammad Farhan Taseer🇨🇳 · Subhash Singha🇨🇳

    The STAR experiment at the top RHIC energy has observed that the directed flow ($v_1$) of inclusive light hadrons is independent of the collision system size at a given centrality~\cite{STAR:2008jgm}. However, recent STAR measurements indicate a system-size dependence in the $v_1(y)$-slope ($d{v}_1/dy$) of protons, antiprotons, and their differences ($\Delta d{v}_1/dy$) at a given centrality, suggesting a potential influence of baryon production and transport mechanisms~\cite{Taseer:SQM2024talk}. We have studied pseudorapidity ($dN/dy$) distributions and directed flow ($v_1$ and $d{v}_1/dy$) for pions, kaons, and protons in Au+Au and Cu+Cu collisions at $\sqrt{s_{NN}}=19.6$ GeV using the A Multi-Phase Transport (AMPT) model. Specifically, we investigated the influence of string junction parameters in AMPT via the PYTHIA/JETSET routines, focusing on the popcorn mechanism and string-splitting parameters, on $dN/dy$, $d{v}_1/dy$, and their charge-dependent splittings ($\Delta dN/dy$ and $\Delta d{v}_1/dy$). We observe that string junction parameters can affect $dN/dy$, $d{v}_1/dy$, $\Delta dN/dy$, and $\Delta d{v}_1/dy$ for $\pi$, K, and p, and influence their system-size dependence. The effect is most prominent on the $v_1$ of protons, non-trivial for kaons, while the pions $v_1$ remain largely unchanged. These findings provide insights into the interplay between particle production mechanisms, baryon transport, and directed flow in heavy-ion collisions.

    ↳ nucl-thhep-exhep-phnucl-exCPC(2025)·0 citations
14. 14*

    Improved Ground State Estimation in Quantum Field Theories via Normalising Flow-Assisted Neural Quantum States

    Vishal S. Ngairangbam🇬🇧 · Michael Spannowsky🇬🇧 · Timur Sypchenko🇬🇧

    We propose a hybrid variational framework that enhances Neural Quantum States (NQS) with a Normalising Flow-based sampler to improve the expressivity and trainability of quantum many-body wavefunctions. Our approach decouples the sampling task from the variational ansatz by learning a continuous flow model that targets a discretised, amplitude-supported subspace of the Hilbert space. This overcomes limitations of Markov Chain Monte Carlo (MCMC) and autoregressive methods, especially in regimes with long-range correlations and volume-law entanglement. Applied to the transverse-field Ising model with both short- and long-range interactions, our method achieves comparable ground state energy errors with state-of-the-art matrix product states and lower energies than autoregressive NQS. For systems up to 50 spins, we demonstrate high accuracy and robust convergence across a wide range of coupling strengths, including regimes where competing methods fail. Our results showcase the utility of flow-assisted sampling as a scalable tool for quantum simulation and offer a new approach toward learning expressive quantum states in high-dimensional Hilbert spaces.

    ↳ quant-phcs.LGhep-lathep-ph0 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.