Wed·Jul 17, 2024Wednesday·July 17, 2024

1. 01*

   Supermassive black hole formation in the initial collapse of axion dark matter

   Pierre Sikivie🇺🇸 · Yuxin Zhao🇺🇸

   Axion dark matter thermalizes by gravitational self-interactions and forms a Bose-Einstein condensate. We show that the rethermalization of the axion fluid during the initial collapse of large scale overdensities near cosmic dawn transports angular momentum outward sufficientlly fast that black holes form with masses ranging from approximately $10^5$ to a few times $10^{10}{M}_{\odot }$. This conclusion holds for QCD axions and for axion-like particles of mass larger than $10^{-16}$ eV/$c^2$.

   hep-phastro-ph.GAPRD(2026)·5 citations
2. 02*

   Axion-Photon Mixing in 3D: Classical Equations and Geometric Optics

   J. I. McDonald🇬🇧 · P. Millington🇬🇧

   Light particle-photon mixing in magnetised plasmas plays a vital role in constraining the existence of new physics, especially axions, dark photons, and ultra-high-frequency gravitational waves. Recently, we derived an expression for the resonant conversion of axions to photons in inhomogeneous media using kinetic theory to derive photon transport equations. In this work, we show how the same expression for the conversion probability can be obtained from the classical wave equations of axion-electrodynamics by deriving an equivalent transport equation along the photon worldline. This result provides further corroboration of this expression for the resonant production of photons from light particles, which has also recently been supported by independent numerical simulations of full axion-electrodynamics. In addition, this new approach provides a more general expression that accounts for mixing away from resonance, which is integrated along the whole worldline of the photon in a way that naturally incorporates a curved photon trajectory relevant to refractive media where the photon and light-particle worldlines differ.

   hep-phastro-ph.COJCAP(2024)·15 citations
3. 03*

   Flavor and path-length dependence of jet quenching from inclusive jet and {\gamma}-jet suppression

   Agnieszka Ogrodnik🇨🇿 · Martin Rybář🇨🇿 · Martin Spousta🇨🇿

   We employ the parametric approach to analyze jet suppression measured using the nuclear modification factor of inclusive jets, $b$-jets, and jets from $\gamma$-jet events. With minimum model assumptions, we quantify the magnitude of the average energy loss and its transverse momentum dependence. Then, we quantify the impact of fluctuations in the energy loss and nuclear PDFs on the measured jet suppression. The Glauber and Trajectum models are used to estimate the average path length that a jet is expected to traverse in the medium. With this information, we quantify the path-length dependence of the average energy loss, which is found to support the physics picture of the radiative nature of parton energy loss. Using the obtained parameterizations, we evaluate jet $v_2$, quantifying its sensitivity to details of path-length modeling. We also provide model-independent predictions for the magnitude of energy loss expected in upcoming oxygen-oxygen collisions and briefly discuss the path-length dependence of energy loss of $b$-jets. Finally, we analyze intriguing features seen in the suppression of jets in the $\gamma$-jet system.

   hep-phEPJC(2025)·16 citations
4. 04*

   Moment Unfolding

   Krish Desai🇺🇸 · Benjamin Nachman🇺🇸 · Jesse Thaler🇺🇸

   Deconvolving ("unfolding'') detector distortions is a critical step in the comparison of cross section measurements with theoretical predictions in particle and nuclear physics. However, most existing approaches require histogram binning while many theoretical predictions are at the level of statistical moments. We develop a new approach to directly unfold distribution moments as a function of another observable without having to first discretize the data. Our Moment Unfolding technique uses machine learning and is inspired by Generative Adversarial Networks (GANs). We demonstrate the performance of this approach using jet substructure measurements in collider physics. With this illustrative example, we find that our Moment Unfolding protocol is more precise than bin-based approaches and is as or more precise than completely unbinned methods.

   hep-phhep-exphysics.data-anstat.MLPRD(2024)·18 citations
5. 05*

   New physical processes for extracting GPDs with a better sensitivity to partonic structure

   Jian-Wei Qiu🇺🇸 · Zhite Yu🇺🇸

   We introduce a new type of exclusive processes for a better study of generalized parton distributions (GPDs), which we refer to as single-diffractive hard exclusive processes (SDHEPs). We advocate a two-stage framework for picturing SDHEPs based on the separation of scales, which gives a clear description both kinematically and dynamically. We examine the sensitivity of the SDHEP to the parton momentum fraction $x$-dependence of GPDs, and demonstrate it quantitatively with two specific processes that can be readily measured at J-PARC or AMBER using a pion beam and at JLab using a photon beam, respectively. Both processes are capable of providing enhanced sensitivity to the $x$-dependence, overcoming the problem of shadow GPDs, and disentangling different types of GPDs with various spin asymmetries.

   hep-phhep-exhep-latnucl-ex+1PoS(2025)·0 citations
6. 06*

   One-loop QCD amplitudes in the Feynman-Diagram gauge

   Kaoru Hagiwara🇯🇵 · Kentarou Mawatari🇯🇵 · Youichi Yamada🇯🇵 · Ya-Juan Zheng🇯🇵

   Scattering amplitudes for the massless QCD process, $q\bar{q}\to q^{\prime }{\bar{q}}^{\prime }$, are calculated in the one-loop order in the Feynman-Diagram (FD) gauge, where gluons are quantized on the light cone with opposite direction of the three-momenta. We find non-decoupling of the Faddeev-Popov ghosts and non-conventional UV singularities in dimensional regularization. The known QCD amplitudes with asymptotic freedom are reproduced only after summing propagator and vertex corrections. By quantizing gluons in the Feynman gauge on the FD gauge background, we obtain the one-loop improved FD gauge amplitudes.

   hep-phPRD(2024)·2 citations
7. 07*

   NNLO Global Analysis of Polarized Parton Distribution Functions

   Ignacio Borsa🇩🇪 · Daniel de Florian🇦🇷 · Rodolfo Sassot🇦🇷 · Marco Stratmann🇩🇪 · Werner Vogelsang🇩🇪

   We present a next-to-next-to-leading order (NNLO) global QCD analysis of the proton's helicity parton distribution functions (PDFs), the first of its kind. To obtain the distributions, we use data for longitudinal spin asymmetries in inclusive and semi-inclusive lepton-nucleon scattering as well as in weak-boson and hadron or jet production in proton-proton scattering. We analyze the data using QCD perturbation theory at NNLO accuracy, employing approximations provided by the threshold resummation formalism in cases where full NNLO results for partonic hard-scattering functions are not readily available. Our numerical results suggest a remarkable perturbative stability of the extracted helicity PDFs.

   hep-phPRL(2024)·49 citations
8. 08*

   Particle Conversions Beyond the WKB Approximation and Solar-Induced Gravitational Waves from Dark Photon Dark Matter

   Tengyu Ai🇨🇳 · Yuxuan He🇨🇳 · Jia Liu🇨🇳 · Xiaolin Ma🇨🇳 · Xiao-Ping Wang🇨🇳

   We investigate the conversion of kinetic mixing dark photon dark matter into gravitational waves within the magnetic field of the Sun. Our study reveals that the WKB approximation is invalid in this scenario. We derive an analytic solution for the conversion probability with unitary evolution feature. This solution aligns in form with previous studies on photon-gravitational wave conversion. Interestingly, it is applicable in situations where the WKB approximation fails. We extend the unitary evolution solution to other conversion processes, such as axion-photon and dark photon-photon conversions. When the WKB approximation conditions are met, this solution reduces to the WKB result. We compute the characteristic strain of gravitational waves resulting from dark photon conversion in the solar magnetic field, spanning frequencies from $10^{-5}$ Hz to $10^6$ Hz. Our findings indicate that the characteristic strain derived from the unitary evolution solution differs significantly from that of the WKB solution. The resulting strain signal is far below the sensitivity of current gravitational wave interferometers. Nevertheless, we have proposed an exotic gravitational wave source, which could be useful in non-minimal dark sector models.

   hep-phPRD(2024)·3 citations
9. 09*

   Evolution of structure functions at NLO without PDFs

   Tuomas Lappi🇫🇮 · Heikki Mäntysaari🇫🇮 · Hannu Paukkunen🇫🇮 · Mirja Tevio🇫🇮

   We formulate the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution of the Deep Inelastic Scattering (DIS) structure functions $F_2$ and $F_{\mathrm{L}}$ at next to leading order in ${\alpha }_s$ (NLO) directly in terms of the structure functions rather than parton distributions (PDFs). We call this the physical basis approach. In practice, we first express the NLO quark singlet and gluon PDFs in terms of the structure functions $F_2$ and $F_{\mathrm{L}}$ in momentum space. Employing these expressions in the DGLAP evolution, we arrive at the evolution equations for $F_2$ and $F_{\mathrm{L}}$ in the physical basis. We demonstrate how one is free from defining a factorization scale and scheme when using the physical basis evolution equations. We also discuss the process of applying the NLO physical basis to global analysis of LHC cross sections.

   hep-phPoS(2025)·0 citations
10. 10*

    Tying knots in particle physics

    Minoru Eto🇯🇵 · Yu Hamada🇩🇪 · Muneto Nitta🇯🇵

    Lord Kelvin's pioneering hypothesis that the identity of atoms is knots of vortices of the aether had a profound impact on the fields of mathematics and physics despite being subsequently refuted by experiments. While knot-like excitations emerge in various systems of condensed matter physics, the fundamental constituents of matter have been revealed to be elementary particles such as electrons and quarks, seemingly leaving no room for the appearance of knots in particle physics. Here, we show that knots indeed appear as meta-stable solitons in a realistic extension of the standard model of particle physics that provides the QCD axion and right-handed neutrinos. This result suggests that during the early Universe, a "knot dominated era" may have existed, where knots were a dominant component of the Universe, and this scenario can be tested through gravitational wave observations. Furthermore, we propose that the end of this era involves the collapse of the knots via quantum tunneling, leading to the generation of matter-antimatter asymmetry in the Universe. Our findings exhibit the significant role of knots in particle physics and represent a modern version of Kelvin's hypothesis.

    hep-phastro-ph.COcond-mat.supr-conhep-thPRL(2025)·11 citations
11. 11*

    A sensitivity target for an impactful Higgs boson self coupling measurement

    Prudhvi N. Bhattiprolu🇺🇸 · James D. Wells🇺🇸

    We argue that a measurement of the Higgs boson self-coupling becomes particularly meaningful in a large and important class of theories when its sensitivity is within 40\% of its Standard Model value. This constitutes a target for a future impactful experimental achievement. It is derived from recently obtained results of how extreme the differences can be between effective field theory operator coefficients when their origins are from reasonable custodial-violating theories beyond the Standard Model.

    hep-phPLB(2025)·5 citations
12. 12*

    A Generic Analysis of Nucleon Decay Branching Fractions in Flipped SU(5) Grand Unification

    Koichi Hamaguchi🇯🇵 · Shihwen Hor🇯🇵 · Natsumi Nagata🇯🇵 · Hiroki Takahashi🇯🇵

    In flipped SU(5) grand unified theories, the partial decay lifetimes of certain nucleon decay channels depend generically on an unknown unitary matrix, which arises when left-handed lepton fields are embedded into anti-fundamental representations of SU(5). This dependency is particularly relevant when the neutrino mass matrix has a generic structure, introducing uncertainty in the prediction of nucleon decay branching fractions within flipped SU(5). In this paper, we demonstrate that this uncertainty can be parametrized using two parameters, which can be determined by measuring the partial lifetimes of $p\to {\pi }^0{e}^{+}$, $p\to {\pi }^0{\mu }^{+}$, and $n\to {\pi }^0\bar{\nu }$. In addition, we establish upper limits on the ratios of the decay widths of these channels, offering a potential method to test flipped SU(5) in future nucleon decay experiments.

    hep-phhep-exUniverse(2024)·0 citations
13. 13*

    Observation of quantum effects on radiation reaction in strong fields

    Eva E. Los🇬🇧 · Elias Gerstmayr🇬🇧 · Christopher Arran🇬🇧 · Matthew J. V. Streeter🇬🇧 · Cary Colgan🇬🇧 · Claudia C. Cobo🇬🇧 · Brendan Kettle🇬🇧 · Thomas G. Blackburn🇸🇪 · Nicolas Bourgeois🇬🇧 · Luke Calvin🇬🇧 · Jason Cardarelli🇺🇸 · Niall Cavanagh🇬🇧 and 19 other authors

    Radiation reaction, the force experienced by an accelerated charge due to radiation emission, has long been the subject of extensive theoretical and experimental research. Experimental verification of a quantum, strong-field description of radiation reaction is fundamentally important, and has wide-ranging implications for astrophysics, laser-driven particle acceleration, next-generation particle colliders and inverse-Compton photon sources for medical and industrial applications. However, the difficulty of accessing regimes where strong field and quantum effects dominate inhibited previous efforts to observe quantum radiation reaction in charged particle dynamics with high significance. We report the first high significance (> 5{\sigma}) observation of strong-field radiation reaction on electron spectra where quantum effects are substantial. We obtain the first, quantitative, strong evidence favouring the quantum-continuous and quantum-stochastic models over the classical model; the quantum models perform comparably. The lower electron energy losses predicted by the quantum models accounts for their improved performance. Model comparison was performed using a novel Bayesian framework which has widespread utility for laser-particle collision experiments, including those utilising conventional accelerators, where some collision parameters cannot be measured directly.

    hep-phphysics.plasm-phNature Commun.(2026)·30 citations
14. 14*

    One-point correlators of conserved and non-conserved charges in QCD

    Marc Riembau🇨🇭 · Minho Son🇰🇷

    One-point correlators of conserved charges are argued to be perturbatively IR safe in QCD, which includes not only the density of energy, but also those of electric charge, isospin and baryon number. Theoretical and phenomenological aspects of the density matrix of one-point correlators are discussed in the context of the states produced by a chiral current, as in the decay of a polarized electroweak boson. Densities of some non-conserved charges such as energy with arbitrary non-negative powers, despite their incalculability, are shown to obey an infinite set of consistency constraints. QCD is observed to live near a kink in the allowed parameter space of one-point correlators.

    hep-phhep-thPRD(2025)·14 citations
15. 15*

    Crossing the desert: Towards predictions for SMEFT coefficients from quantum gravity

    Lydia Brenner🇳🇱 · Abhishek Chikkaballi🇵🇱 · Astrid Eichhorn🇩🇰 · Shouryya Ray🇩🇰

    The SMEFT provides a general framework to search for new physics beyond the current reach of direct detection. One such form of new physics is quantum gravity. Based on dimensional analysis, one would expect the prediction that the quantum-gravity contribution to the SMEFT coefficients is unmeasurably tiny at LHC scales. In this paper, we test this expectation in a specific framework for quantum gravity, namely the asymptotic safety framework. In this framework, Wilson coefficients can be calculated in relatively straightforward manner, making a connection between quantum gravity and LHC tests of the SMEFT achievable. We work in a toy model of the Standard Model fermion sector to investigate four-fermion couplings. We find three scenarios in this toy model, based on three distinct fixed points of the Renormalization Group flow. In the first scenario, the expectation from dimensional analysis is borne out and Wilson coefficients are Planck-scale suppressed. In the second and third scenarios, the Wilson coefficients are significantly larger than expected by dimensional analysis, due to interacting fixed points which generate an effective new-physics scale that lies between the LHC scale and the Planck scale. We comment on the implications of these results for the testability of asymptotically safe gravity within the SMEFT framework at the LHC.

    hep-phgr-qchep-th5 citations
16. 16*

    Triply charm and bottom tetraquarks in a constituent quark model

    Gang Yang🇨🇳 · Jialun Ping🇨🇳 · Jorge Segovia🇪🇸

    Singly, doubly and fully charmed tetraquark candidates, \emph{e.g.}, $T_{c\bar{s}}(2900)$, $T_{cc}^{+}(3875)$ and $X(6900)$ have been recently reported by the LHCb collaboration. Therefore, it is timely to implement a theoretical investigation on triply heavy tetraquark systems; herein, the S-wave triply charm and bottom tetraquarks, $\bar{Q}Q\bar{q}Q$ $(q=u,d,s;Q=c,b)$, with spin-parity $J^P=0^{+}$, $1^{+}$ and $2^{+}$, isospin $I=0$ and $\frac{1}{2}$, are systematically studied in a constituent quark model. Besides, all tetraquark configurations, \emph{i.e.} meson-meson, diquark-antidiquark and K-type arrangements, along with any allowed color structure, are comprehensively considered. The Gaussian expansion method (GEM), in combination with the complex-scaling method (CSM), which is quite ingenious in dealing with either bound or resonances, is the approach adopted in solving the complex scaled Schrödinger equation. This theoretical framework has already been applied in various tetra- and penta-quark systems. In a fully coupled-channel calculation within the GEM$+$CSM, narrow resonances are found in each $I(J^P)$ channel of the charm and bottom sector. In particular, triply charm and bottom tetraquark resonances are obtained in $5.6-5.9$ GeV and $15.3-15.7$ GeV, respectively. We provide also some insights of the compositeness of these exotic states, such as the inner quark distance, magnetic moment and dominant wave function component. All this may help to distinguish them in future high energy nuclear and particle experiments.

    hep-phhep-exhep-latnucl-ex+1PRD(2024)·10 citations
17. 17*

    A New Non-Renormalization Theorem from UV/IR Mixing

    Steven Abel🇬🇧 · Keith R. Dienes🇺🇸 · Luca A. Nutricati🇬🇧

    In this paper, we prove a new non-renormalization theorem which arises from UV/IR mixing. This theorem and its corollaries are relevant for all four-dimensional tachyon-free closed string theories which can be realized from higher-dimensional theories via geometric compactifications. As such, they therefore apply regardless of the presence or absence of spacetime supersymmetry and regardless of the gauge symmetries or matter content involved. This theorem resolves a hidden clash between modular invariance and the process of decompactification, and enables us to uncover a number of surprising phenomenological properties of these theories. Chief among these is the fact that certain physical quantities within such theories cannot exhibit logarithmic or power-law running and instead enter an effective fixed-point regime above the compactification scale. This cessation of running occurs as the result of the UV/IR mixing inherent in the theory. These effects apply not only for gauge couplings but also for the Higgs mass and other quantities of phenomenological interest, thereby eliminating the logarithmic and/or power-law running that might have otherwise appeared for such quantities. These results illustrate the power of UV/IR mixing to tame divergences -- even without supersymmetry -- and reinforce the notion that UV/IR mixing may play a vital role in resolving hierarchy problems without supersymmetry.

    ↳ hep-thhep-phPRD(2024)·18 citations
18. 18*

    Gravitationally dominated instantons and instability of dS, AdS and Minkowski spaces

    Viatcheslav F. Mukhanov🇩🇪 · Yaron Oz🇮🇱 · Alexander S. Sorin🇷🇺

    We study the decay of the false vacuum in the regime where the quantum field theory analysis is not valid, since gravitational effects become important. This happens when the height of the barrier separating the false and the true vacuum is large, and it has implications for the instability of de Sitter, Minkowski and anti-de Sitter vacua. We carry out the calculations for a scalar field with a potential coupled to gravity, and work within the thin-wall approximation, where the bubble wall is thin compared to the size of the bubble. We show that the false de Sitter vacuum is unstable, independently of the height of the potential and the relative depth of the true vacuum compared to the false vacuum. The false Minkowski and anti-de Sitter vacua can be stable despite the existence of a lower energy true vacuum. However, when the relative depth of the true and false vacua exceeds a critical value, which depends on the potential of the false vacuum and the height of the barrier, then the false Minkowski and anti-de Sitter vacua become unstable. We calculate the probability for the decay of the false de Sitter, Minkowski and anti-de Sitter vacua, as a function of the parameters characterizing the field potential.

    ↳ hep-thgr-qchep-phmath-ph+2JHEP(2024)·1 citation
19. 19*

    Fay identities for polylogarithms on higher-genus Riemann surfaces

    Eric D'Hoker🇺🇸 · Oliver Schlotterer🇸🇪

    A recent construction of polylogarithms on Riemann surfaces of arbitrary genus in arXiv:2306.08644 is based on a flat connection assembled from single-valued non-holomorphic integration kernels that depend on two points on the Riemann surface. In this work, we construct and prove infinite families of bilinear relations among these integration kernels that are necessary for the closure of the space of higher-genus polylogarithms under integration over the points on the surface. Our bilinear relations generalize the Fay identities among the genus-one Kronecker-Eisenstein kernels to arbitrary genus. The multiple-valued meromorphic kernels in the flat connection of Enriquez are conjectured to obey higher-genus Fay identities of exactly the same form as their single-valued non-holomorphic counterparts. We initiate the applications of Fay identities to derive functional relations among higher-genus polylogarithms involving either single-valued or meromorphic integration kernels.

    ↳ hep-thhep-phmath.AGmath.NT25 citations
20. 20*

    Holographic Lifshitz flows

    Matteo Baggioli🇨🇳 · Oriol Pujolas🇪🇸 · Xin-Meng Wu🇨🇳

    Without Lorentz symmetry, generic fixed points of the renormalization group (RG) are labelled by their dynamical (or `Lifshitz') exponent $z$. Hence, a rich variety of possible RG flows arises. The first example is already given by the standard non-relativistic limit, which can be viewed as the flow from a $z=1$ UV fixed point to a $z=2$ IR fixed point. In strongly coupled theories, there are good arguments suggesting that Lorentz invariance can emerge dynamically in the IR from a Lorentz violating UV. In this work, we perform a generic study of fixed points and the possible RG flows among them in a minimal bottom-up holographic model without Lorentz invariance, aiming to shed light on the possible options and the related phenomenology. We find: i) A minor generalization of previous models involving a massive vector field with allowed self-couplings leads to a much more efficient emergence of Lorentz invariance than in the previous attempts. Moreover, we find that generically the larger is the UV dynamical exponent $z_{UV}$ the faster is the recovery of Lorentz symmetry in the IR. ii) We construct explicitly a holographic model with a line of fixed points, realizing different Lifshitz scaling along the line. iii) We also confirm the monotonicity of a recently proposed a-function along all our Lorentz violating RG flows.

    ↳ hep-thhep-phJHEP(2024)·6 citations
21. 21*

    Measurement of the branching fraction of $D_s^{+}\to {\ell }^{+}{\nu }_{\ell }$ via $e^{+}{e}^{-}\to D_s^{\ast +}{D}_s^{\ast -}$

    BESIII Collaboration: M. Ablikim · M. N. Achasov · P. Adlarson · O. Afedulidis · X. C. Ai · R. Aliberti · A. Amoroso · Q. An · Y. Bai · O. Bakina · I. Balossino · Y. Ban and 646 other authors

    Based on $10.64{\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ collision data taken at center-of-mass energies between 4.237 and 4.699 GeV with the BESIII detector, we study the leptonic $D_s^{+}$ decays using the $e^{+}{e}^{-}\to D_s^{\ast +}{D}_s^{\ast -}$ process. The branching fractions of $D_s^{+}\to {\ell }^{+}{\nu }_{\ell }(\ell =\mu ,\tau )$ are measured to be $\mathcal{B}(D_s^{+}\to {\mu }^{+}{\nu }_{\mu })=(0.547\pm 0.026_{\mathrm{stat}}\pm 0.016_{\mathrm{syst}})\%$ and $\mathcal{B}(D_s^{+}\to {\tau }^{+}{\nu }_{\tau })=(5.60\pm 0.16_{\mathrm{stat}}\pm 0.20_{\mathrm{syst}})\%$, respectively. The product of the decay constant and Cabibbo-Kobayashi-Maskawa matrix element $|V_{cs}|$ is determined to be $f_{D_s^{+}}|V_{cs}|=(246.5\pm 5.9_{\mathrm{stat}}\pm 3.6_{\mathrm{syst}}\pm 0.5_{\mathrm{input}}{)}_{\mu \nu }\mathrm{MeV}$ and $f_{D_s^{+}}|V_{cs}|=(252.7\pm 3.6_{\mathrm{stat}}\pm 4.5_{\mathrm{syst}}\pm 0.6_{\mathrm{input}}){)}_{\tau \nu }\mathrm{MeV}$, respectively. Taking the value of $|V_{cs}|$ from a global fit in the Standard Model, we obtain $f_{D_s^{+}}=(252.8\pm 6.0_{\mathrm{stat}}\pm 3.7_{\mathrm{syst}}\pm 0.6_{\mathrm{input}}{)}_{\mu \nu }$ MeV and $f_{D_s^{+}}=(259.2\pm 3.6_{\mathrm{stat}}\pm 4.5_{\mathrm{syst}}\pm 0.6_{\mathrm{input}}{)}_{\tau \nu }$ MeV, respectively. Conversely, taking the value for $f_{D_s^{+}}$ from the latest lattice quantum chromodynamics calculation, we obtain $|V_{cs}|=(0.986\pm 0.023_{\mathrm{stat}}\pm 0.014_{\mathrm{syst}}\pm 0.003_{\mathrm{input}}{)}_{\mu \nu }$ and $|V_{cs}|=(1.011\pm 0.014_{\mathrm{stat}}\pm 0.018_{\mathrm{syst}}\pm 0.003_{\mathrm{input}}{)}_{\tau \nu }$, respectively.

    ↳ hep-exhep-phPRD(2024)·12 citations
22. 22*

    Evidence for a $\sim 43$ GeV $\gamma$-ray line signal in a stacking analysis of the Virgo, Fornax, and Ophiuchus Galaxy clusters

    Yi-Zhong Fan🇨🇳 · Zhao-Qiang Shen🇨🇳 · Yun-Feng Liang🇨🇳 · Xiang Li🇨🇳 · Kai-Kai Duan🇨🇳 · Zi-Qing Xia🇨🇳 · Xiao-Yuan Huang🇨🇳 · Lei Feng🇨🇳 · Qiang Yuan🇨🇳

    As the largest gravitationally bound objects in the Universe, galaxy clusters have provided the first piece of evidence for the presence of dark matter and may be suitable targets for indirect dark matter searches. Among various signals, the GeV-TeV $\gamma$-ray line has been taken as the smoking-gun signal of the dark matter annihilation and decay since no known astrophysical or physical process(es) could generate such a peculiar spectrum. With 15.5 years of Fermi-LAT P8R3 publicly available data, we search for the $\gamma$-ray line emission in the directions of 13 massive galaxy clusters at redshifts $z\le 0.028$ with an unbinned likelihood analysis. A $\gamma$-ray line signal at $\sim 43.2$ GeV has a net test statistic (TS) value of $\approx 30$ if we take into account only the data in the directions of the Virgo, Fornax, and Ophiuchus clusters, three massive clusters with the highest J-factors expected to generate the dark matter annihilation signal. The signal still presents when the data of 10 other nearby massive clusters have also been included, though the TS value decreases to $\approx 21$, likely because of their lower signal-to-noise ratios. The absence of this signal in the inner Galaxy disfavors both the instrumental effect and the canonical dark matter annihilation interpretation, and a more sophisticated dark matter model or very peculiar astrophysical scenario might be needed. This $\gamma$-ray line signal, if intrinsic, could be unambiguously verified by the Very Large Area $\gamma$-ray Space Telescope in its first two years of performance.

    ↳ astro-ph.HEastro-ph.COhep-phPRL(2026)·15 citations
23. 23*

    Energy dependence of the knee in the cosmic ray spectrum across the Milky Way

    C. Prevotat🇫🇷 · M. Kachelriess🇳🇴 · S. Koldobskiy🇫🇮 · A. Neronov🇫🇷 · D. Semikoz🇫🇷

    The all-particle spectrum of cosmic rays measured at Earth has a knee-like feature around 4 PeV. A priori, it is not clear if this is a local feature specific to the Solar neighbourhood in the Milky Way, or if it is a generic property of the Galactic cosmic-ray spectrum. We argue that combining gamma-ray and cosmic-ray data of LHAASO indicates that the knee is a local feature. In order to demonstrate this, we derive a model for the local cosmic-ray spectrum and composition, consistent with the recent LHAASO measurements of the all-particle spectrum and the mean logarithmic mass in the knee region. We calculate the spectrum of diffuse gamma-ray emission based on this model and find that the expected spectral shape of the diffuse gamma-ray flux disagrees with the LHAASO measurements of the diffuse gamma-ray emission in the 10-100 TeV energy range in the inner and outer Galaxy. We determine the break energy in the CR spectrum expected from these gamma-ray data and find it an energy ten times lower than obtained from local measurements.

    ↳ astro-ph.HEhep-phPRD(2024)·13 citations
24. 24*

    The CONUS+ experiment

    The CONUS Collaboration: N. Ackermann🇩🇪 · S. Armbruster🇩🇪 · H. Bonet🇩🇪 · C. Buck🇩🇪 · K. Fulber🇩🇪 · J. Hakenmuller🇩🇪 · J. Hempfling🇩🇪 · G. Heusser🇩🇪 · M. Lindner🇩🇪 · W. Maneschg🇩🇪 · K. Ni🇩🇪 · M. Rank🇩🇪 and 6 other authors

    The CONUS+ experiment aims to detect coherent elastic neutrino-nucleus scattering (CEvNS) of reactor antineutrinos on germanium nuclei in the fully coherent regime, continuing on this way the CONUS physics program started at the Brokdorf nuclear power plant, Germany. The CONUS+ setup is installed in the nuclear power plant in Leibstadt, Switzerland, at a distance of 20.7 m from the 3.6 GW thermal power reactor core. The CEvNS signature will be measured with the same four point-contact high-purity germanium (HPGe) detectors produced for the former experiment, however refurbished and with optimized low energy thresholds. To suppress the background in the CONUS+ detectors, the passive and active layers of the original CONUS shield were modified such to fit better to the significantly changed background conditions at the new experimental location. New data acquisition and monitoring systems were developed. A direct network connection between the experiment and the Max-Planck-Institut fur Kernphysik (MPIK) makes it possible to control and monitor data acquisition in real time. The impact of all these modifications is discussed with particular emphasis on the resulting CEvNS signal prediction for the first data collection phase of CONUS+. Prospects of the planned upgrade in a second phase integrating new larger HPGe detectors are also discussed.

    ↳ hep-exhep-phEPJC(2024)·43 citations
25. 25*

    Holographic QCD Running Coupling for Light Quarks in Strong Magnetic Field

    Irina Ya. Aref'eva🇷🇺 · Ali Hajilou🇷🇺 · Alexander Nikolaev🇷🇺 · Pavel Slepov🇷🇺

    We consider running coupling constant in holographic model with external magnetic field supported by Einstein-dilaton-three-Maxwell action. We obtain a significant dependence of the running coupling constant $\alpha$ on chemical potential, temperature and magnetic field. We use the boundary condition that ensures the agreement with lattice calculations of string tension between quarks at zero chemical potential. The location of the 1st order phase transitions in $(\mu ,T)$-plane does not depend on the dilaton boundary conditions. We observe that running coupling $\alpha$ decreases with increasing magnetic field for the fixed values of chemical potential and temperature. At the 1st order phase transitions the functions $\alpha$ undergo jumps depending on temperature, chemical potential and magnetic field.

    ↳ hep-thhep-phPRD(2024)·13 citations
26. 26*

    Modular Invariant Starobinsky Inflation and the Species Scale

    Gonzalo F. Casas🇪🇸 · Luis E. Ibáñez🇪🇸

    Potentials in cosmological inflation often involve scalars with trans-Planckian ranges. As a result, towers of states become massless and their presence pushes the fundamental scale not to coincide with $M_{\mathrm{P}}$ but rather with the $speciesscale$, $\Lambda$. This scale transforms as an automorphic form of the theory's duality symmetries. We propose that the inflaton potential should be 1) an automorphic invariant form, non-singular over all moduli space, 2) depending only on $\Lambda$ and its field derivatives, and 3) approaching constant values in the large moduli to ensure a long period of inflation. These conditions lead to the proposal $V\sim \lambda (\varphi ,{\varphi }^{\ast })$, with $\lambda =G^{i\bar{j}}({\partial }_i\Lambda )({\partial }_{\bar{j}}\Lambda )/{\Lambda }^2$, determining the 'species scale convex hull'. For a single elliptic complex modulus with $SL(2,Z)$ symmetry, this results in an inflaton potential $V\simeq (\text{Im}\tau {)}^2|{\tilde{G}}_2{|}^2/N^2$, with $N\simeq -\log (\text{Im}\tau |\eta (\tau ){|}^4)$, where $\eta$ is the Dedekind function and ${\tilde{G}}_2$ the Eisenstein modular form of weight 2. Surprisingly, this potential at large modulus resembles that of the Starobinsky model. We compute inflation parameters yielding results similar to Starobinsky's, but extended to modular invariant expressions. Interestingly, the number of e-folds is proportional to the number of species in the tower, $N_e\simeq N$, and $ϵ\simeq {\Lambda }^4$ at large moduli, suggesting that the tower of states plays an important role in the inflation process.

    ↳ hep-thastro-ph.COgr-qchep-phJHEP(2025)·39 citations
27. 27*

    Bulk Black Hole Dark Matter

    Luis A. Anchordoqui🇺🇸 · Ignatios Antoniadis🇹🇭 · Dieter Lust🇩🇪 · Karem Peñaló Castillo🇺🇸

    The dark dimension provides a mechanism to resolve the cosmological hierarchy problem and assembles a colosseum for dark matter contenders. In a series of recent publications we investigated whether primordial black holes (PBHs) perceiving the dark dimension could constitute all of the dark matter in the universe. A key assumption of these investigations is that PBHs remain confined to the brane during the entire evaporation process. As a consequence, the abundance of PBHs evaporating at the present epoch is severely constrained by observations of both the extragalactic and Galactic $\gamma$-ray backgrounds. As a natural outgrowth of these investigations, herein we relax the assumption of brane localized PBHs and reexamine the evaporation process of PBHs which are allowed to escape into the dark dimension. We show that the escape of PBHs from the brane is almost instantaneous. Armed with this pivotal finding we reassess the allowed mass range of PBHs to assemble all cosmological dark matter, which is estimated to be $10^{11}\lesssim M_{\mathrm{BH}}/\mathrm{g}\lesssim 10^{21}$.

    ↳ hep-thastro-ph.COhep-phPhys.Dark Univ.(2024)·16 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.