Thu·May 29, 2025Thursday·May 29, 2025

1. 01*

   High-Frequency Gravitational Waves on BREAD

   Rodolfo Capdevilla🇺🇸 · Roni Harnik🇺🇸 · Taegyun Kim🇰🇷 · Tom Krokotsch🇩🇪

   The use of light axion dark matter experiments as high-frequency gravitational wave (HFGW) detectors has garnered increasing attention in recent years. We explore the capabilities of the Broadband Reflector Experiment for Axion Detection (BREAD) in probing the GW parameter space and study the directional dependence of its coverage. This detector can investigate frequencies ranging from 0.05 to 200 THz. We find that employing single photon detectors BREAD is sensitive to GWs with characteristic strains as low as $10^{-21}$ at 0.1 THz and $10^{-25}$ at 200 THz with a year exposure time, making it competitive with other proposals operating at similar frequencies.

   hep-phPRD(2025)·11 citations
2. 02*

   Primordial black holes from Q-balls produced in a first-order phase transition

   James B. Dent🇺🇸 · Bhaskar Dutta🇺🇸 · Jason Kumar🇺🇸 · Danny Marfatia🇺🇸

   We consider the formation of Q-balls in false vacuum remnants during a cosmological first-order phase transition. We find that under certain circumstances Q-balls can collapse to form primordial black holes. This scenario can produce multimessenger signals that may be observed at upcoming experiments, including 1-100 nHz gravitational waves from the phase transition, and gamma-rays emitted from primordial black holes as Hawking radiation and as superradiance. These signals are quite distinctive, and differ markedly from signals expected from Fermi-balls. The reheating of the dark sector from the phase transition may address the Hubble tension.

   hep-phastro-ph.COhep-ex8 citations
3. 03*

   Gravitational wave signatures of primordial black hole accretion during early matter domination

   Rouzbeh Allahverdi🇺🇸 · James B. Dent🇺🇸 · Ngo Phuc Duc Loc🇺🇸 · Tao Xu🇺🇸

   We present a scenario in which primordial black holes (PBHs) form in a post-inflationary radiation-dominated (RD) phase and then experience significant accretion during a phase of early matter dominated (EMD). We show that PBH masses could grow by up to two orders of magnitude. Restricting to the linear perturbation regime, we compute the gravitational wave (GW) spectrum that features two peaks. The high-frequency peak is associated with the PBH formation in the RD phase, while the low-frequency peak is due to the sudden transition from EMD to the later, standard RD phase. We identify a PBH mass range where one or both peaks can be observed by a combination of different GW detectors. Finally, we show the signal-to-noise ratio of the total GW spectrum for PBHs in the asteroid mass window, where they could comprise the totality of dark matter.

   hep-phastro-ph.COgr-qcJCAP(2025)·3 citations
4. 04*

   Hydrogen-like structures in the strong interaction

   Lei Liu🇨🇳 · Yanmei Xiao🇨🇳 · Tao Guo🇨🇳

   Heavy flavor hadrons, especially doubly heavy baryons and doubly heavy tetraquarks, have always received extensive attention in theoretical and experimental research. Given the separation of quark masses $m_Q\gg m_q$ ($Q=c,b$ and $q=u,d,s$), this type of heavy flavor hadrons can be well regarded as hydrogen-like structures in the strong interaction. In the theoretical framework of Born-Oppenheimer approximation, we derive the Schrödinger equation for the motion of light quarks in the effective potential field of heavy quarks. Taking proper account of the color-spin hyperfine interaction, we carry out a systematic study on the mass spectra of $S$-wave doubly heavy baryons and doubly heavy tetraquarks. The model parameters required for the calculation are obtained by fitting conventional hadrons. The investigation on the doubly heavy baryon systems indicates the reliability of our theoretical approach. Our calculation results show that the experimentally discovered $T_{cc}^{+}$ is most likely a compact tetraquark $|(cc{)}_0^6(\bar{u}\bar{d}{)}_1^{\bar{6}}⟩$ state with quantum numbers $(I,J^P)=(0,1^{+})$. Forthermore, for different quantum number assignments, some stable tetraquark states are found and may be very narrow peaks. The predictions for other heavy flavor hadrons are expected to be confirmed in new theories and future experiments.

   hep-phPRD(2025)·4 citations
5. 05*

   IceCube PeV neutrinos from heavy dark matter decay with 12 years HESE data

   Diptarko Mukherjee🇮🇳 · Ashadul Halder🇮🇳 · Debasish Majumdar🇮🇳 · Abhijit Bandyopadhyay🇮🇳

   The decay of superheavy dark matter from the early universe may undergo decay via QCD cascades and electroweak cascade to produce neutrinos as one of the decay products. We consider the neutrino events in and around PeV region reported by IceCube collaboration are due to the decay of such heavy dark matter. The neutrino spectrum could be from the decay processes via hadronic decay modes and/or leptonic decay modes. Using the numerical evolution of QCD cascades as well as electroweak corrections where use has been made of DGLAP equations, the neutrino fluxes from the heavy dark matter decay have been computed. The mass of the decaying superheavy dark matter and its decay lifetime have then been estimated from a ${\chi }^2$ analysis of the IceCube 12-year data. The fractional contribution ($f_{\mathrm{lep}}$) of the leptonic decay channel in such a decay process is also estimated from the same ${\chi }^2$ analyses. It is seen that to explain the IceCube 12-year ultrahigh energy (UHE) events the mass of a decaying superheavy dark matter would be $\sim 9.4\times 10^6$ GeV and decay time $\tau \simeq 4.2\times 10^{28}$ second. It is also found that the lepton channel contribution is very small, $f_{\mathrm{lep}}\sim 0.001$.

   hep-phastro-ph.HE1 citation
6. 06*

   Probing the sensitivity of anisotropic flow coefficients to the initial nuclear structure in pO and OO collisions at the LHC

   Aswathy Menon Kavumpadikkal Radhakrishnan🇮🇳 · Suraj Prasad🇮🇳 · Neelkamal Mallick🇫🇮 · Raghunath Sahoo🇮🇳 · Gergely Gábor Barnaföldi🇭🇺

   RHIC and LHC have injected ${}^{16}\mathrm{O}$ nuclei in their accelerator complexes with a focus on investigating collectivity and the origin of quark-gluon plasma signatures in small collision systems. The ${}^{16}\mathrm{O}$ nuclei are known to possess clusters of $\alpha$-particles (${}^4\mathrm{He}$) inside the nucleus. This paper attempts to study the clustered-nuclear-geometry dependence of anisotropic flow coefficients such as elliptic flow ($v_2$) and triangular flow ($v_3$), which are sensitive to the nuclear geometry of colliding nuclei. The study is performed in pO and OO collisions at $\sqrt{s_{\mathrm{NN}}}=9.61$~TeV and 7~TeV respectively, employing a hybrid model encompassing IP-Glasma + MUSIC + iSS + UrQMD. The results of the clustered nuclear geometry are compared with those of the Woods\,--\,Saxon nuclear profile. Both initial and final state anisotropies are estimated. This study is thus one of its first kind, where the study of anisotropic flow coefficients for pO and OO collisions is presented using a hybrid hydrodynamics model. While the effect of $\alpha$-clustering in pO is found to be small, it is significant for each observable studied in OO collisions. It is also observed that the magnitude of this effect has a noteworthy dependence on the size of the \textsuperscript{4}He.

   hep-phhep-exhep-thnucl-ex+1PLB(2025)·7 citations
7. 07*

   Exploring Charm Bound States: Mass Spectra and Decay Dynamics of D Mesons and $Cq\bar{q}\bar{q}$ Tetraquarks

   Chetan lodha🇮🇳 · Manak Parmar🇮🇳 · Ajay Kumar Rai🇮🇳

   Motivated by the discovery of several charm states exhibiting tetraquark-like characteristics at BESIII and LHCb, this study investigates the spectroscopy and decay properties of D mesons and tetraquark states with quark content $Cq\bar{q}\bar{q}$ within the diquark - antidiquark framework. The analysis is performed using a potential model based on the Cornell potential, considering color antitriplet - triplet configurations. Mass spectra are computed for both mesons and tetraquarks, while their decay behaviors are examined using the factorization approach for D mesons and Fierz rearrangement for tetraquark decays. Theoretical results are compared with experimentally observed resonances to improve our understanding of charm quark bound systems.

   hep-phInt.J.Mod.Phys.A(2025)·7 citations
8. 08*

   $\rho \to \pi \pi$ Hadronic Decay in the Nambu-Jona-Lasinio Model: Mass-Width Interplay and Beyond-RPA Corrections

   Qing-Wu Wang🇨🇳 · Xiao-Fu Ł\textü · Hua-Zhong Guo🇨🇳

   We present a novel framework for analyzing unstable composite particles using Green's functions and dispersion relations. As an illustrative example, we explore the $\rho$ vector meson decay process $\rho \to \pi \pi$ within the Nambu -- Jona - Lasinio (NJL) model. Our approach addresses a key limitation of the four-quark interaction description, which adequately describes two-quark bound states but fails to describe decay processes. The Bethe-Salpeter(BS) wave function of the $\rho$ meson exhibits time evolution that leads to the physical mass $M$ incorporating a correction $\Delta M$. This correction depends on the decay width $\Gamma (M)$. This work provides crucial insights into the dynamical relationship between resonance masses and their decay properties, addressing a long-standing challenge in hadron physics. The calculated mass and width are in good agreement with the experimental values, demonstrating the effectiveness of this approach for studying unstable hadronic systems beyond conventional bound-state approximations.

   hep-phCPC(2026)·0 citations
9. 09*

   Opening up New Parameter Space for Sterile Neutrino Dark Matter

   P. S. Bhupal Dev🇺🇸 · Bhaskar Dutta🇺🇸 · Srubabati Goswami🇮🇳 · Jianrong Paul Tang🇺🇸 · Aaroodd Ujjayini Ramachandran🇺🇸

   Sterile neutrinos are compelling dark matter (DM) candidates, yet the minimal production mechanism solely based on active (${\nu }_a$)-sterile (${\nu }_s$) oscillations is excluded by astrophysical observations. Non-standard self-interactions in either active (${\nu }_a-{\nu }_a$) or sterile (${\nu }_s-{\nu }_s$) sector are known to alter the sterile neutrino DM production in the early Universe, which could alleviate the tension with astrophysical constraints to some extent. Here we propose a novel solution where scalar-mediated non-standard interactions between active and sterile neutrinos (${\nu }_a-{\nu }_s$) generate new production channels for ${\nu }_s$, independent of the active-sterile mixing and without the need for any fine-tuned resonance or primordial lepton asymmetry. This framework enables efficient sterile neutrino DM production even at vanishingly small mixing angles and opens up new viable regions of parameter space that can be tested with future $X$-ray and gamma-ray observations.

   hep-phastro-ph.COPRD(2026)·10 citations
10. 10*

    Renormalizing the Quark-Meson-Diquark Model

    Hosein Gholami🇩🇪 · Lennart Kurth🇩🇪 · Ugo Mire🇩🇪 · Michael Buballa🇩🇪 · Bernd-Jochen Schaefer🇩🇪

    We present a comprehensive study of the two-flavor Quark--Meson--Diquark (QMD) model by comparing a renormalization approach with a renormalization-group (RG) consistent mean-field formulation based on the functional renormalization group (FRG). The renormalized QMD model allows analytical investigations of key quantities such as the zero-temperature diquark gap and the critical temperature for color superconductivity, ultimately reproducing the exact BCS relation in the high-density limit. We carry out the same analysis for different schemes of RG-consistent QMD models. We show that the RG-consistent approach yields a phase diagram and thermodynamic properties qualitatively similar to those of the renormalized model, provided both are embedded within a unified scheme that ensures consistent vacuum properties. In particular, both treatments recover the Stefan--Boltzmann limit at high densities. On the other hand, whether the BCS relation for the critical temperature is satisfied depends on the details of the RG-consistent setup. Our results highlight the relevance of renormalization and RG-consistent methods for accurately capturing the thermodynamics of QMD and related effective models with diquark degrees of freedom.

    hep-phhep-thnucl-thPRD(2026)·22 citations
11. 11*

    Genesis of baryon and dark matter asymmetries through ultraviolet scattering freeze-in

    Pouya Asadi🇺🇸 · Marianne Moore🇺🇸 · David E. Morrissey🇨🇦 · Michael Shamma🇨🇦

    We introduce a new mechanism for the simultaneous generation of baryon and dark matter asymmetries through ultraviolet-dominated freeze-in scatterings. The mechanism relies on heavy Majorana neutrinos that connect the visible Standard Model sector to a dark sector through the neutrino portal. Following reheating of the visible sector to a temperature well below the heavy neutrino masses, we show that 2-to-2 scattering processes can populate the dark sector and generate both baryon and dark matter asymmetries. In some parameter regions, the dominant source of baryon asymmetry can be charge transfer from the dark sector, a process we call dark wash-in. We also demonstrate that annihilation of the dark matter to massless states within the dark sector can deplete the symmetric population without destroying the net baryon charge to leave only an asymmetric dark matter abundance today. Depending on the specific model parameters, the observed baryon and dark matter abundances can be attained with heavy neutrino masses $M_N\gtrsim 10^{10}$ GeV, and dark matter masses in the range 0.1 GeV $\lesssim m_{\chi }\lesssim 10^3$ GeV if the dark matter relic abundance is mainly asymmetric and even lower masses if it is symmetric.

    hep-phPRD(2026)·5 citations
12. 12*

    Astrophysical flux of dark particles as a solution to the KM3NeT and IceCube tension over KM3-230213A

    Yasaman Farzan🇮🇷 · Matheus Hostert🇺🇸

    We entertain the possibility that transient astrophysical sources can produce a flux of dark particles that induce ultra-high-energy signatures at neutrino telescopes such as IceCube and KM3NeT. We construct scenarios where such ``dark flux" can produce meta-stable dark particles inside the Earth that subsequently decay to muons, inducing through-going tracks in large-volume neutrino detectors. We consider such a scenario in light of the $\mathcal{O}(70)$~PeV ultra-high-energy muon observed by KM3NeT and argue that because of its location in the sky and the strong geometrical dependence of the signal, such events would not necessarily have been observed by IceCube. Our model relies on the upscattering of a new particle $X$ onto new metastable particles that decay to dimuons with decay lengths of $\mathcal{O}(100)$~km. This scenario can explain the observation by KM3NeT without being in conflict with the IceCube data.

    hep-phJHEP(2025)·17 citations
13. 13*

    On Pulsar Timing Detection of Ultralight Vector Dark Matter

    Jeff A. Dror🇺🇸 · Qiushi Wei🇺🇸

    Ultralight vector dark matter induces metric fluctuations that generate timing residuals in the arrival times of pulsar emissions through two distinct modes: a fast mode, sourced by coherent field oscillations, and a slow mode, arising from interference patterns. These modes enable the detection of vector dark matter with masses $m\sim 10^{-24}-10^{-22}\mathrm{eV}$ and $m\sim 10^{-18}-10^{-16}\mathrm{eV}$, respectively, using pulsar timing arrays. While previous studies have explored the fast mode, they neglect the full statistical treatment of the vector field and a precise treatment of its polarization structure. In this work, we investigate the timing residuals from both modes, fully accounting for the statistical properties of ultralight vector dark matter, assuming equipartition among its three polarization states. The two-point correlation functions of timing residuals that we derive serve as direct tools for identifying vector dark matter signatures as a stochastic background in pulsar timing data.

    hep-phastro-ph.HEPRD(2025)·10 citations
14. 14*

    Explaining the PeV Neutrino Fluxes at KM3NeT and IceCube with Quasi-Extremal Primordial Black Holes

    Michael J. Baker🇺🇸 · Joaquim Iguaz Juan🇺🇸 · Aidan Symons🇺🇸 · Andrea Thamm🇺🇸

    The KM3NeT experiment has recently observed a neutrino with an energy around 100PeV, and IceCube has detected five neutrinos with energies above 1PeV. While there are no known astrophysical sources, exploding primordial black holes could have produced these high-energy neutrinos. For Schwarzschild black holes this interpretation results in tensions between the burst rates inferred from the KM3NeT and IceCube observations, with indirect constraints from the extragalactic gamma ray background and with the non-observation of an associated gamma ray signal at LHAASO. In this letter we show that if there is a population of primordial black holes charged under a new dark $u(1)$ symmetry which spend most of their time in a quasi-extremal state, the neutrino emission at 1PeV may be more suppressed than at 100PeV. The burst rates implied by the KM3NeT and IceCube observations and the indirect constraints can then all be consistent at $1\sigma$, and no associated gamma-ray signal was expected at LHAASO. Furthermore, these black holes could constitute all of the observed dark matter in the universe.

    hep-phastro-ph.COPRL(2026)·25 citations
15. 15*

    Langer's nucleation rate reproduced on the lattice

    Joonas Hirvonen🇬🇧 · Oliver Gould🇬🇧

    We show that Langer's rate of bubble nucleation is quantitatively correct up to small higher-loop corrections, in comparison to lattice simulations. These results are a significant advancement on decades of lattice studies showing only qualitative trends, and the first showing agreement for any conservative system. We confirm that the failure to fully thermalize the metastable phase explains discrepancies with recent lattice studies that found disagreement with Langer's rate. The key theoretical development is the translation of Langer's perturbative definition of a thermal metastable phase into a nonperturbative statement that can be implemented on the lattice. Our statistical and systematic errors are small enough to allow us to measure on the lattice the coefficient of the two-loop contribution, missing from the perturbative prediction. Our conclusions also exclude a possible systematic uncertainty in ${}^3$He experiments.

    hep-phastro-ph.COcond-mat.stat-mechhep-lat+1PRL(2026)·13 citations
16. 16*

    Prospect of Constraining the EoS of Neutron Stars Using Post-Merger Signals

    Soham Mitra🇮🇳 · Praveer Tiwari🇮🇳 · Archana Pai🇮🇳

    Post-merger gravitational-wave emission from a binary neutron star merger carries crucial information about the equation of state (EoS) of matter at high temperatures. Current gravitational wave detectors have limited sensitivities at post-merger frequencies in the range [1.5, 4] kHz. Therefore, valuable inferences can only be made after combining information from multiple (BNS) events. Criswell et al. [Phys. Rev. D 107, 043021 (2023)] carries out an injection study to infer the radius posterior for a $1.6M_{\odot }$ NS by combining the information from injected BNS events via the hierarchical Bayesian inference (HBI) formulation. This formulation utilizes empirical relations that connect the peak frequency of the post-merger remnant with the chirp mass of the system, and the EoS proxy parameter $R_{1.6}$. In this work, we extend the HBI formulation to other EoS proxy parameters (i.e., the radius of (NS), $R_{1.X}$, with masses 1.2, 1.4, and 1.8 $M_{\odot }$) and combine the four $R_{1.X}$ posteriors through the piecewise polytropic EoS model to obtain measurable constraints on the EoS of the NS. We show that the NS radii can be constrained to within $\sim$1 km ( $\sim$0.55 km) assuming uniform (astrophysical) prior on $R_{1.X}$ for injections in the A+ noise. We also study systematic biases in the analysis coming from the limitations of empirical relations.

    ↳ astro-ph.HEgr-qchep-phnucl-th+1J.Subatomic Part.Cosmol.(2026)·4 citations
17. 17*

    Spin polarization of holographic baryon in strongly coupled fluid

    Si-wen Li🇨🇳 · Shu Lin🇨🇳

    The spin polarization for baryon in a hydrodynamic medium has been extensively studied in the weakly coupled regime using quantum kinetic theory. As a first study of this problem in the strongly coupled regime, we investigate holographically the spectral function of a probe baryon in the fluid-gravity background. This is done by carefully performing gradient expansion of the Dirac equation in the fluid-gravity background. Different contributions in the expansion are understood in terms of density matrices of the probe baryon and the medium. The resulting spectral functions indicate that the holographic baryonic is polarized as responses to fluid acceleration, shear stress and vorticity. The structures of the responses are similar to those found in weakly coupled studies.

    ↳ hep-thhep-phnucl-thPRD(2025)·4 citations
18. 18*

    Cosmic Strings as Dynamical Dark Energy: Novel Constraints

    Hanyu Cheng🇨🇳 · Eleonora Di Valentino🇬🇧 · Luca Visinelli🇮🇹

    Cosmic strings, topological defects predicted by high-energy theories, may contribute to the late-time expansion of the Universe, effectively mimicking dynamical dark energy. We investigate four phenomenological extensions of the $\Lambda$CDM model involving a residual string network: (i) a non-relativistic component with positive energy density (Model~1), (ii) a velocity-dependent extension (Model~2), (iii) a non-relativistic string network with energy density allowed to take both positive and negative values (Model~3), and (iv) a general scenario with free energy and velocity parameters (Model~4). These models are constrained using \textit{Planck} CMB data, SDSS or DESI baryon acoustic oscillations, and Type Ia supernovae observations. Models~1 and~2 yield strong upper bounds on the string density, for example, ${\Omega }_{\mathrm{s}}<0.00901$ at 95\% CL from the CMB+DESI+DESY5 combination for Model~2, and mildly shift the inferred value of $H_0$ upward, though they are not favored by Bayesian evidence. For the same combination, the bulk velocity is bound as $v_{\mathrm{s}}<0.569$. Models~3 and~4 exhibit a consistent preference for slightly negative values of ${\Omega }_{\mathrm{s}}$, with CMB-only data yielding ${\Omega }_{\mathrm{s}}=-0.038_{-0.022}^{+0.029}$ and $v_{\mathrm{s}}<0.574$ in Model~4, and a best-fit improvement of $\Delta {\chi }^2=-6.07$. However, these improvements are not sufficient to overcome the Occam penalty, and the Bayesian evidence continues to favor $\Lambda$CDM. These findings demonstrate the power of current data to constrain exotic energy components and encourage further exploration of string-inspired extensions to $\Lambda$CDM, particularly those involving negative-tension networks.

    ↳ astro-ph.COhep-phJHEAp(2026)·33 citations
19. 19*

    Model-independent cosmological inference after the DESI DR2 data with improved inverse distance ladder

    Jia-Le Ling🇺🇸 · Guo-Hong Du🇺🇸 · Tian-Nuo Li🇺🇸 · Jing-Fei Zhang🇺🇸 · Shao-Jiang Wang🇨🇳 · Xin Zhang🇺🇸

    Recently, the baryon acoustic oscillations (BAO) measurements from the DESI survey have suggested hints of dynamical dark energy, challenging the standard $\Lambda$CDM model. In this work, we adopt an improved inverse distance ladder approach based on the latest cosmological data to provide a model-independent perspective, employing a global parametrization based on cosmic age (PAge). Our analysis incorporates DESI DR2 BAO measurements, cosmic chronometer (CC) data, and type Ia supernovae (SNe) observations from either the DESY5 or PantheonPlus datasets. For the DESY5+DESI DR2+CC datasets, we obtain $H_0=67.91\pm 2.33\mathrm{km}{\mathrm{s}}^{-1}\mathrm{Mp}{\mathrm{c}}^{-1}$. This value is consistent with the Planck 2018 result, while shows $2.0\sigma$ tension with the SH0ES measurement. Furthermore, by mapping specific cosmological models into PAge approximation parameter space $(p_{\mathrm{age}},\eta )$, our model-independent analysis reveals a notable deviation from the $\Lambda \mathrm{CDM}$ model, as indicated by the DESY5 and DESI DR2 datasets. Finally, DESY5+DESI DR2+CC datasets provide nearly decisive evidence favoring the PAge model over the standard $\Lambda \mathrm{CDM}$ model. These findings highlight the need for further investigation into the expansion history to better understand the deviations from the $\Lambda \mathrm{CDM}$ model.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2025)·44 citations
20. 20*

    Science for Peace and the need for Civil Clauses at universities and civilian research institutions

    J. Altmann · U. Amaldi · M. Barone · A. Bassalat · M. Bona🇬🇧 · J. Beullens · H. Brand🇩🇪 · S. Brentjes · D. Britzger🇩🇪 · J. Ellis🇬🇧 · S. Franchoo🇫🇷 · A. Giammanco🇧🇪 and 18 other authors

    After the end of World War II, the commitment to confine scientific activities in universities and research institutions to peaceful and civilian purposes has entered, in the form of {\it Civil Clauses}, the charters of many research institutions and universities. In the wake of recent world events, the relevance and scope of such Civil Clauses has been questioned in reports issued by some governments and by the EU Commission, a development that opens the door to a possible blurring of the distinction between peaceful and military research. This paper documents the reflections stimulated by a panel discussion on this issue recently organized by the Science4Peace Forum. We review the adoptions of Civil Clauses in research organizations and institutions in various countries, present evidence of the challenges that are emerging to such Civil Clauses, and collect arguments in favour of maintaining the purely civilian and peaceful focus of public (non-military) research.

    ↳ physics.soc-phhep-exhep-ph0 citations
21. 21*

    Off-shell form factor: factorization is violated

    A.V. Belitsky🇺🇸 · V.A. Smirnov🇷🇺

    We study the Sudakov form factor on the Coulomb branch of N=4 sYM, which endows only external states with masses, and implies that the former is off-shell in the traditional sense. Our consideration is performed at three-loop order in the near mass-shell limit. We use a combination of tools to perform required calculations centered around the Method of Regions as the main go-to formalism for the asymptotic expansion of emerging parametric Feynman integrals. Explicit separation of quantum loops in terms of hard, collinear, and ultrasoft modes allows us to explore the factorization properties of this infrared-sensitive quantity. While the hard region is cleanly separated from the rest, the ultrasoft-collinear modes remain intertwined. We exhibit effects of factorization violation explicitly in the momentum space making use of the infrared power counting.

    ↳ hep-thhep-phPRD(2026)·5 citations
22. 22*

    Cosmological constraints on small-scale primordial non-Gaussianity

    Jing-Zhi Zhou🇨🇳 · Zhi-Chao Li🇨🇳 · Di Wu🇨🇳

    In contrast to the large-scale primordial power spectrum ${\mathcal{P}}_{\zeta }(k)$ and primordial non-Gaussianity $f_{\mathrm{NL}}$, which are strictly constrained, the small-scale ${\mathcal{P}}_{\zeta }(k)$ and $f_{\mathrm{NL}}$ remain less restricted. Considering local-type primordial non-Gaussianity, we study the PBH and SIGW caused by large-amplitude small-scale primordial power spectrum. By analyzing current observational data from PTA, CMB, BAO, and abundance of PBH, and combining them with the SNR analysis of LISA, we rigorously constrain the parameter space of ${\mathcal{P}}_{\zeta }(k)$ and $f_{\mathrm{NL}}$. Furthermore, we examine the effects of different shapes of the primordial power spectrum on these constraints and comprehensively calculate the Bayes factors for various models. Our results indicate that SIGW generated by a monochromatic primordial power spectrum are more likely to dominate current PTA observations, with the corresponding constraint on the primordial non-Gaussian parameter being $-10.0<f_{\mathrm{NL}}<1.2$.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2025)·7 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.