Thu·Feb 8, 2024Thursday·February 8, 2024

1. 01*

   Quantum vortex phases of charged pion condensates induced by rotation in a magnetic field

   Tao Guo🇨🇳 · Yanmei Xiao🇨🇳

   Using the relativistic complex scalar field model with a repulsive self-interaction, we discuss the ground state structure of charged pion condensation under the coexistence of parallel rotation and magnetic field. Our previous study found that the density distribution profile of the condensates is a supergiant quantum vortex phase and change with rotational speed and coupling constant. In this work, we further discover vortex lattice structures in the condensates under conditions of small rotation and strong coupling constant. This mechanism can be thought of as electrical superconductivity: Vortex lattices are created to better adapt to changes in rotation and interaction. Furthermore, large rotation and weak coupling constant are more likely to cause the vortex lattices to be destroyed and form a giant quantum vortex similar to a doughnut. We expect this phenomenon can be observed in the relativistic non-central heavy ion collisions with large rotation and strong magnetic field.

   hep-phPRD(2024)·4 citations
2. 02*

   Quarkonium dynamics in the quantum Brownian regime with non-abelian quantum master equations

   Stéphane Delorme🇵🇱 · Roland Katz🇫🇷 · Thierry Gousset🇫🇷 · Pol Bernard Gossiaux🇫🇷 · Jean-Paul Blaizot🇫🇷

   We present numerical solutions in a one-dimensional setting of quantum master equations that have been recently derived. We focus on the dynamics of a single heavy quark-antiquark pair in a Quark-Gluon Plasma in thermal equilibrium, in the so-called quantum Brownian regime where the temperature of the plasma is large in comparison with the spacing between the energy levels of the $Q\bar{Q}$ system. The one-dimensional potential used in the calculations has been adjusted so as to produce numbers that are relevant for the phenomenology of the charmonium. The equations are solved using different initial states and medium configurations. Various temperature regimes are studied and the effects of screening and collisions thoroughly analyzed. Technical features of the equations are analyzed. The contributions of the different operators that control the evolution are discussed as a function of the temperature. Some phenomenological consequences are addressed.

   hep-phhep-thquant-phJHEP(2024)·26 citations
3. 03*

   Neutrinoless Double Beta Decay in Multiple Isotopes for Fingerprints Identification of Operators and Models

   Shao-Long Chen🇨🇳 · Yu-Qi Xiao🇨🇳

   Neutrinoless double beta ($0\nu \beta \beta$) decay is the most promising way to determine whether neutrinos are Majorana particles. There are many experiments based on different isotopes searching for $0\nu \beta \beta$ decay. Combining the searches of $0\nu \beta \beta$ decay in multiple isotopes provides a possible method to distinguish operators and different models. The contributions to $0\nu \beta \beta$ decay come from standard, long-range, and short-range mechanisms. We analyze the scenario in which the standard and short-range operators exist simultaneously within the framework of low-energy effective field theory. Five specific models are considered, which can realize neutrino mass and can contribute to $0\nu \beta \beta$ decay via multiple mechanisms. A criterion to evaluate the possibilities of future experiments to discriminate operators and models is built. We find that the complementary searches for $0\nu \beta \beta$ decay in different isotopes can distinguish the cases that contain the low-energy effective operators ${\mathcal{O}}_{1,2,5}$ and R-parity violating supersymmetry model. For other cases and models, the experimental searches within multiple isotopes can also more effectively constrain the parameter region than with only one isotope.

   hep-phJHEP(2024)·5 citations
4. 04*

   The single parton fragmentation functions of heavy quarkonium in soft gluon factorization

   Qi-Lin Jia🇨🇳 · An-Ping Chen🇨🇳 · Yuan-Guo Xu🇨🇳

   We study the single parton fragmentation functions (FFs) at the input factorization scale ${\mu }_0\gtrsim 2m_Q$, with heavy quark mass $m_Q$, in the soft gluon factorization (SGF) approach. We express the FFs in terms of perturbatively calculable short distance hard parts for producing a heavy quark-antiquark pair in all possible states, convoluted with corresponding soft gluon distribution for the hadronization of the pair to a heavy quarkonium. We compute the perturbative short distance hard parts for producing a heavy quark pair in all possible $S$-wave and $P$-wave states up to $O({\alpha }_s^2)$. With our results, the SGF can be further used to study the heavy quarkonium production at the hadron colliders and heavy quarkonium production within a jet.

   hep-phPRD(2024)·4 citations
5. 05*

   Systematic local simulations of fast neutrino flavor conversions with scattering effects

   Milad Delfan Azari🇯🇵 · Hirokazu Sasaki🇺🇸 · Tomoya Takiwaki🇯🇵 · Hirotada Okawa🇯🇵

   We investigate the dynamics of fast neutrino flavor conversions (FFCs) in the one-dimensional (1D) and zero-dimensional (0D) models, in which spatial advection is considered and ignored, respectively. In this study, we employ snapshots obtained by our self-consistent, realistic Boltzmann-neutrino-radiation-hydrodynamics simulations. We show that the FFC growth rate is considerably larger in the 1D model than in the 0D model, as expected from the previous linear analysis results. We find that the momentum space dimension does not significantly influence the neutrino transition probability in 1D models. On the other hand, in the 0D model without collisions, the FFC depends on the momentum space, and the azimuthal angle dependence breaks the periodicity of the FFC. Our study demonstrates that collisional instability can lead to further flavor conversions on a long time scale in 1D models after the asymptotic state of FFC has been reached. Such an effect should be taken into consideration when the fast and collisional flavor instabilities coexist.

   hep-phastro-ph.HEPTEP(2024)·7 citations
6. 06*

   Temperature evolution in the Early Universe and freeze-in at stronger coupling

   Catarina Cosme🇵🇹 · Francesco Costa🇩🇪 · Oleg Lebedev🇫🇮

   Dark matter freeze-in at stronger coupling is operative when the Standard Model (SM) bath temperature never exceeds the dark matter mass. An attractive feature of this scenario is that it can be probed by direct detection experiments as well as at the LHC. In this work, we show how the mechanism can be realized in a simple UV complete framework, emphasizing the role of the maximal temperature of the SM thermal bath. We demonstrate that the maximal temperature can coincide with the reheating temperature or be close to it such that dark matter production is always Boltzmann-suppressed. This possibility is realized, for example, if the inflaton decays primarily into feebly interacting right-handed neutrinos, which subsequently generate the SM thermal bath. In this case, the SM sector temperature remains constant over cosmological times prior to reheating.

   hep-phastro-ph.COJCAP(2024)·50 citations
7. 07*

   Muon $g-2$ and Proton Lifetime in SUSY SU(5) GUTs with Split Superpartners

   Seong-Sik Kim🇰🇷 · Hyun Min Lee🇰🇷 · Sung-Bo Sim🇰🇷

   We consider the interplay of the muon $g-2$ anomaly and the proton decay in the SUSY SU(5) GUTs with generation-independent scalar soft masses. In these scenarios, we introduce a number of $5+\bar{5}$ messenger fields with doublet-triplet splitting in general gauge mediation to transmit SUSY breaking to the visible sector by gauge loops. As a result, squarks and sleptons receive generation-independent soft SUSY breaking masses, which are split already at the messenger scale. Taking into account the perturbative unification of gauge couplings as well as the bounds from electroweak precision and vacuum stability bounds, we showed the parameter space in general gauge mediation to explain the muon $g-2$ anomaly with smuon and sneutrino loops while evading the strong bounds on squarks and gluinos from the Large Hadron Collider. We also obtained the dominant Higgsino contributions to the proton decay mode, $p\to K^{+}\bar{\nu }$, with general generation-independent sparticle masses for squarks and sleptons. Even for split scalar soft masses in our model, however, we found that the bounds from the proton decay are satisfied only if the effective Yukawa couplings of the colored Higgsinos are suppressed further by a factor of order $10^{-4}-10^{-3}$. We illustrated how such a suppression factor is realized in orbifold GUTs in the extra dimension where the colored Higgsinos in the bulk are not coupled to the matter fields localized at the orbifold fixed points at the leading order.

   hep-phhep-thPRD(2024)·3 citations
8. 08*

   How much strangeness is needed for the axial-vector form factor of the nucleon?

   Felix Hermsen🇩🇪 · Tobias Isken🇩🇪 · David Thoma🇩🇪 · Matthias F.M. Lutz🇩🇪

   We consider the axial-vector together with its induced pseudo-scalar form factor of the nucleon as computed from the chiral Lagrangian with nucleon and isobar degrees of freedom. The form factors are evaluated at the one-loop level, where particular emphasis is put on the use of on-shell masses in the loop expressions. Our results are presented in terms of a novel set of basis functions that generalize the Passarino--Veltman scheme to the case where power-counting violating structures are to be subtracted. The particularly important role of the isobar degrees of freedom is emphasized. We obtain a significant and simultaneous fit to the available Lattice QCD results based on flavour SU(2) ensembles for the baryon masses and form factors up to pion masses of about 500 MeV. Our fits includes sizeable finite volume effects that are implied by using in-box values for the hadron masses entering our one-loop expressions. We conclude that from flavour SU(2) ensembles it appears not possible to predict the empirical formfactor at the desired precision. Effects from strange quarks are expected to remedy the situation.

   hep-phPRD(2024)·4 citations
9. 09*

   Jet transport coefficients by elastic and radiative scatterings in the strongly interacting quark-gluon plasma

   Ilia Grishmanovskii🇩🇪 · Olga Soloveva🇩🇪 · Taesoo Song🇩🇪 · Carsten Greiner🇩🇪 · Elena Bratkovskaya🇩🇪

   We extend the investigation on jet transport coefficients within the effective Dynamical QuasiParticle Model (DQPM) -- constructed for the description of non-perturbative QCD phenomena of the strongly interacting quark-gluon plasma (sQGP) in line with the lattice QCD equation-of-state -- by accounting for inelastic $2\to 3$ reactions with gluon radiation additionally to the elastic scattering of partons. The elastic and inelastic reactions are calculated explicitly within leading-order Feynman diagrams with effective propagators and vertices from the DQPM by accounting for all channels and their interferences. We present the results for the jet transport coefficients such as the transverse momentum transfer squared $\hat{q}$ per unit length as well as the energy loss $\Delta E=dE/dx$ per unit length in the sQGP and investigate their dependence on the temperature $T$ and momentum of the jet parton depending on the choice of the strong coupling constant ${\alpha }_s$ in thermal, jet parton and radiative vertices. For the latter we consider different scenarios used in the literature and find a very strong dependence of $\hat{q}$ and $\Delta E$ on the choice of ${\alpha }_s$. Moreover, we explore the relation of $\hat{q}/T^3$ to the ratio of specific shear viscosity to entropy density $\eta /s$ and show that the ratio $T^3/\hat{q}$ to $\eta /s$ has a strong $T$ dependence -- especially when approaching to $T_c$ -- on the choice of ${\alpha }_s$ in scattering vertices.

   hep-phPRC(2024)·7 citations
10. 10*

    Non-relativistic trace anomaly and equation of state in dense fermionic matter

    Hiroyuki Tajima🇯🇵 · Kei Iida🇯🇵 · Haozhao Liang🇯🇵

    We theoretically investigate a non-relativistic trace anomaly and its impact on the low-temperature equation of state in spatially one-dimensional three-component fermionic systems with a three-body interaction, which exhibit a non-trivial three-body crossover from a bound trimer gas to dense fermionic matter with increasing density. By applying the $G$-matrix approach to the three-body interaction, we obtain the analytical expression for the ground-state equation of state relevant to the high-density degenerate regime and thereby address how the three-body contact or, equivalently, the trace anomaly emerges. The analytical results are compared with the recent quantum Monte Carlo data. Our study of the trace anomaly and the sound speed could have some relevance to the physics of hadron-quark crossover in compact stars.

    hep-phcond-mat.quant-gashep-thnucl-thPRC(2024)·6 citations
11. 11*

    Once-in-a-lifetime encounter models for neutrino media: From coherent oscillations to flavor equilibration

    Anson Kost (UNM)🇺🇸 · Lucas Johns (LANL)🇺🇸 · Huaiyu Duan (UNM)🇺🇸

    Collective neutrino oscillations are typically studied using the lowest-order quantum kinetic equation, also known as the mean-field approximation. However, some recent quantum many-body simulations suggest that quantum entanglement among neutrinos may be important and may result in flavor equilibration of the neutrino gas. In this work, we develop new quantum models for neutrino gases in which any pair of neutrinos can interact at most once in their lifetimes. A key parameter of our models is $\gamma =\mu \Delta z$, where $\mu$ is the neutrino coupling strength, which is proportional to the neutrino density, and $\Delta z$ is the duration over which a pair of neutrinos can interact each time. Our models reduce to the mean-field approach in the limit $\gamma \to 0$ and achieve flavor equilibration in time $t\gg (\gamma \mu {)}^{-1}$. These models demonstrate the emergence of coherent flavor oscillations from the particle perspective and may help elucidate the role of quantum entanglement in collective neutrino oscillations.

    hep-phastro-ph.HEnucl-thquant-phPRD(2024)·29 citations
12. 12*

    Two-loop anomalous dimensions for small-$R$ jet versus hadronic fragmentation functions

    Melissa van Beekveld🇳🇱 · Mrinal Dasgupta🇬🇧 · Basem Kamal El-Menoufi🇬🇧 · Jack Helliwell🇬🇧 · Alexander Karlberg🇨🇭 · Pier Francesco Monni🇨🇭

    We study the collinear fragmentation of highly energetic jets defined with a small jet radius. In particular, we investigate how the corresponding fragmentation functions differ from their hadronic counterpart defined in the common $\overline{\mathrm{MS}}$ scheme. We find that the anomalous dimensions governing the perturbative evolution of the two fragmentation functions differ starting at the two loop order. We compute for the first time the new anomalous dimensions at two loops and confirm our predictions by comparing the inclusive small-$R$ jet spectrum against a fixed order perturbative calculation at $\mathcal{O}({\alpha }_s^2)$. To investigate the dependence of the anomalous dimension on the kinematic cutoff variable, we study the fragmentation functions of Cambridge jets defined with a transverse momentum cutoff as opposed to an angular cutoff $R$. We further study the evolution of the small-$R$ fragmentation function with an alternative cutoff scale, proportional to $zR$, representing the maximum possible transverse momentum of emissions within a jet. In these cases we find that the two-loop anomalous dimensions coincide with the $\overline{\mathrm{MS}}$ DGLAP ones, highlighting a correspondence between the $\overline{\mathrm{MS}}$ scheme and a transverse-momentum cutoff.

    hep-phJHEP(2024)·15 citations
13. 13*

    Can quantum statistics help distinguish Dirac from Majorana neutrinos?

    Evgeny Akhmedov🇩🇪 · Andreas Trautner🇩🇪

    Finding out if neutrinos are Dirac or Majorana particles is known to be extremely difficult due to the smallness of neutrino mass and the fact that in the limit $m_{\nu }=0$ both Dirac and Majorana neutrinos become Weyl particles, i.e. are indistinguishable. There have been suggestions in the literature that in the case of processes with production of a neutrino-antineutrino pair (if neutrinos are Dirac particles) or two neutrinos (if they are of Majorana nature) quantum statistics may be of help. This is because for Majorana neutrinos quantum indistinguishability of identical particles requires the amplitude of the process to be antisymmetrized with respect to the interchange of the final-state neutrinos, whereas no such antisymmetrization must be done for Dirac neutrinos. It has been claimed that the resulting differences between the cross sections for Dirac and Majorana neutrinos persist even for arbitrarily small but not exactly vanishing neutrino mass. We demonstrate that, at least in the framework of the Standard Model, this is not the case. We also give a general proof that within the Standard Model quantum statistics does not help tell Dirac and Majorana neutrinos apart in the limit of negligibly small $m_{\nu }/E$.

    hep-phhep-exnucl-thJHEP(2024)·9 citations
14. 14*

    Three-point Energy Correlators in Hadronic Higgs Decays

    Tong-Zhi Yang🇨🇭 · Xiaoyuan Zhang🇺🇸

    We present the analytic calculation of the leading order three-point energy correlator (EEEC) in hadronic Higgs decays, including both gluon-initiated channel $H\to gg+X$ and quark-initiated channel $H\to q\bar{q}+X$. The phase space integration is evaluated directly using Mandelstam variables $s_{ij}=(p_i+p_j{)}^2$, and the appearing square roots can be rationalized by either conformal ratios or celestial coordinate variables. Throughout the calculation, we observe the same transcendental function space as in $\mathcal{N}=4$ super Yang-Mills (SYM) theory and $e^{+}{e}^{-}\to \text{ hadrons}$. Different infrared limits are also explored using the full analytic result, offering the fixed-order data for EEEC factorization and resummation. Given its non-trivial shape dependence, the EEEC presents an excellent opportunity to explore the dynamics of gluon jets originating from the $H\to gg$ decay channel at future lepton colliders.

    hep-phhep-exPRD(2024)·22 citations
15. 15*

    Magnetogenesis with gravitational waves and primordial black hole dark matter

    Shyam Balaji🇬🇧 · Malcolm Fairbairn🇬🇧 · Maria Olalla Olea-Romacho🇫🇷

    Strongly supercooled first order phase transitions (FOPTs) can produce primordial black hole (PBH) dark matter (DM) along with observable gravitational waves (GWs) from bubble collisions. Such FOPTs may also produce coherent magnetic fields generated by bubble collisions and by turbulence in the primordial plasma. Here we find that the requirement for PBH DM can produce large primordial magnetic fields which subsequently yield intergalactic magnetic fields in the present universe (with magnitude $\lesssim 20$ pG across coherence length scales of $\simeq 0.001$-$0.01$ Mpc, assuming maximally helical magnetic fields) that easily exceed lower bounds from blazar observations. We follow a largely model independent approach and highlight the possibility of producing DM and observable multi-messenger magnetic fields and GW signals visible in next generation experiments.

    hep-phastro-ph.COastro-ph.HEPRD(2024)·24 citations
16. 16*

    Semiclassics for the QCD vacuum structure through $T^2$-compactification with the baryon-'t Hooft flux

    Yui Hayashi🇯🇵 · Yuya Tanizaki🇯🇵

    We study QCD vacuum structure with the topological $\theta$ angle using a recently proposed semiclassical approach on ${\mathbb{R}}^2\times T^2$ with the 't Hooft and baryon magnetic fluxes. Under the assumption of adiabatic continuity in this setup, the confining vacuum can be described by the dilute gas of center vortices. With this semiclassical approach, we derive the 2d effective description at small $T^2$ and successfully explain the reasonable theta dependence of the QCD vacuum: In the one-flavor QCD at $\theta =\pi$, the $CP$ symmetry is spontaneously broken for quark mass above a critical value and restored for a subcritical mass, while the $CP$ symmetry is always spontaneously broken in the multi-flavor QCD at $\theta =\pi$. From our semiclassical description, we discuss implications to the $4$d chiral Lagrangian and propose how the ${\eta }^{\prime }$ meson should be incorporated in consistent with known global structures: The periodicity of the ${\eta }^{\prime }$ should be extended from the naive one $2\pi$ to $2\pi N$. Additionally, we revisit the phase diagram of $N_f=1+1$ and $N_f=1+1+1$ QCD on the up and down quark mass plane, confirming and refining the existence of the $CP$-broken Dashen phase.

    ↳ hep-thhep-lathep-phnucl-thJHEP(2024)·32 citations
17. 17*

    Characterization of a Transmon Qubit in a 3D Cavity for Quantum Machine Learning and Photon Counting

    Alessandro D'Elia🇮🇹 · Boulos Alfakes · Anas Alkhazaleh · Leonardo Banchi🇮🇹 · Matteo Beretta🇺🇸 · Stefano Carrazza🇮🇹 · Fabio Chiarello🇮🇹 · Daniele Di Gioacchino🇮🇹 · Andrea Giachero🇮🇹 · Felix Henrich🇩🇪 · Alex Stephane Piedjou Komnang🇮🇹 · Carlo Ligi🇮🇹 and 10 other authors

    In this paper we report the use of superconducting transmon qubit in a 3D cavity for quantum machine learning and photon counting applications. We first describe the realization and characterization of a transmon qubit coupled to a 3D resonator, providing a detailed description of the simulation framework and of the experimental measurement of important parameters, like the dispersive shift and the qubit anharmonicity. We then report on a Quantum Machine Learning application implemented on the single-qubit device to fit the u-quark parton distribution function of the proton. In the final section of the manuscript we present a new microwave photon detection scheme based on two qubits coupled to the same 3D resonator. This could in principle decrease the dark count rate, favouring applications like axion dark matter searches.

    ↳ quant-phhep-phAppl.Sciences(2024)·13 citations
18. 18*

    Comparative Study of Quarkonium Transport in Hot QCD Matter

    A. Andronic🇩🇪 · P.B. Gossiaux🇫🇷 · P. Petreczky🇺🇸 · R. Rapp🇺🇸 · M. Strickland🇺🇸 · J.P. Blaizot🇫🇷 · N. Brambilla🇩🇪 · P. Braun-Munzinger🇩🇪 · B. Chen🇨🇳 · S. Delorme🇵🇱 · X. Du🇪🇸 · M. A. Escobedo🇪🇸 and 10 other authors

    This document summarizes the efforts of the EMMI Rapid Reaction Task Force on "Suppression and (re)generation of quarkonium in heavy-ion collisions at the LHC", centered around their 2019 and 2022 meetings. It provides a review of existing experimental results and theoretical approaches, including lattice QCD calculations and semiclassical and quantum approaches for the dynamical evolution of quarkonia in the quark-gluon plasma as probed in high-energy heavy-ion collisions. The key ingredients of the transport models are itemized to facilitate comparisons of calculated quantities such as reaction rates, binding energies, and nuclear modification factors. A diagnostic assessment of the various results is attempted and coupled with an outlook for the future.

    ↳ nucl-thhep-phEPJA(2024)·74 citations
19. 19*

    Stairway to equilibrium entropy

    Romulo Rougemont🇧🇷 · Willians Barreto🇧🇷

    We compute the time evolution of the non-equilibrium entropy in the homogeneous isotropization dynamics of the 1RCBH model, which has a critical point in its conformal phase diagram defined at finite temperature and R-charge density. We also evaluate the time evolution of the pressure anisotropy and the scalar condensate of the medium. We disclose a new feature (not present in the Bjorken flow dynamics analyzed in previous works), which is observed for all the analyzed initial data: the formation of a periodic sequence of several close plateaus in the form of a stairway for the entropy density near thermodynamic equilibrium. We find that the period of plateau formation in the stairway is half the period of oscillations of the slowest quasinormal mode of the system, which is therefore strongly tied to the late time dissipative dynamics of the system associated to the irreversibility of entropy production. For the particular case of the purely thermal SYM plasma at zero density and vanishing scalar condensate, we find that the period of the stairway is half the period of oscillations of the slowest quasinormal mode associated to the late time equilibration of the pressure anisotropy of the fluid, while at finite chemical potential the slowest quasinormal mode of the system is associated to the late time equilibration of the scalar condensate.

    ↳ hep-thgr-qchep-phPRD(2024)·7 citations
20. 20*

    Applying Simulation-Based Inference to Spectral and Spatial Information from the Galactic Center Gamma-Ray Excess

    Katharena Christy🇺🇸 · Eric J. Baxter🇺🇸 · Jason Kumar

    The two most favored explanations of the Fermi Galactic Center gamma-ray excess (GCE) are millisecond pulsars and self annihilation of the smooth dark matter halo of the galaxy. In order to distinguish between these possibilities, we would like to optimally use all information in the available data, including photon direction and energy information. To date, analyses of the GCE have generally treated directional and energy information separately, or have ignored one or the other completely. Here, we develop a method for analyzing the GCE that relies on simulation-based inference with neural posterior models to jointly analyze photon directional and spectral information while correctly accounting for the spatial and energy resolution of the telescope, here assumed to be the Fermi Large Area Telescope (LAT). Our results also have implications for analyses of the diffuse gamma-ray background, which we discuss.

    ↳ astro-ph.HEastro-ph.COastro-ph.GAhep-phJCAP(2024)·7 citations
21. 21*

    Interpretation of AMS-02 beryllium isotope fluxes using data-driven production cross sections

    Meng-Jie Zhao🇨🇳 · Xiao-Jun Bi🇨🇳 · Kun Fang🇨🇳 · Peng-Fei Yin🇨🇳

    The Be isotopic measurements preliminarily reported by the AMS-02 Collaboration have reached an unprecedented energy of 12 GeV/$n$. As secondary cosmic rays (CRs), the Be isotopes include both stable and unstable species, which are crucial for constraining the propagation parameters of Galactic CRs. However, uncertainties in their production cross sections can skew the interpretation of the CR data, especially when cross-section measurements are of significantly lower quality than CR measurements. In this work, we consider the uncertainties of the cross sections to interpret the Be isotopic data by adopting a cross-section parametrization that fully utilizes the available experimental data. Owing to the high-quality measurements of the ${}^7$Be production cross section, we innovatively employ ${}^7$Be instead of ${}^9$Be to constrain propagation parameters. Notably, the diffusion halo thickness is constrained to $5.67\pm 0.76$~kpc, representing a moderate value compared to previous analogous works. Combining the well-constrained CR propagation model and the precise CR measurements of ${}^9$Be, we conversely constrain the major production cross section of ${}^9$Be and find that it ought to be remarkably lower than previously thought. Our analysis also questions the reliability of certain cross sections measured by some experiments, potentially marking the first time CR data has been used to identify dubious nucleon production cross sections. The method presented in this work holds promise for analyzing upcoming isotopic data from other nuclei.

    ↳ astro-ph.HEhep-phnucl-exPRD(2024)·8 citations
22. 22*

    Out of the Dark: WISPs in String Theory and the Early Universe

    Joseph P. Conlon🇬🇧

    New light hidden sector degrees of freedom represent one of the most approaches to going beyond the Standard Model. I give a short account of how such WISP candidates naturally appear in string compactifications and some descriptions of ways that they can affect early universe cosmology.

    ↳ hep-thhep-phPoS(2024)·5 citations
23. 23*

    The Galactic center excess at the highest energies: morphology and photon-count statistics

    Silvia Manconi🇫🇷 · Francesca Calore🇫🇷 · Fiorenza Donato🇮🇹

    The nature of the GeV gamma-ray Galactic center excess (GCE) in the data of Fermi-Large Area Telescope (LAT) is still to be unveiled. We present a new analysis of the inner Galaxy Fermi-LAT data at energies above 10 GeV, based on an innovative method which combines the skyFACT adaptive template fitting with and the 1pPDF pixel-count statistics. We find a strong evidence for the GCE also at high energies, $\sigma >5$ regardless of the GCE spatial template. Remarkably, our fits prefer the bulge morphological model over the dark matter one at high significance, and show no evidence for an additional dark matter template on top of the bulge component. Through the 1pPDF analysis, we find that the model best describing the gamma-ray data requires a smooth, diffuse GCE following a bulge morphology, together with sub-threshold point sources. The 1pPDF fit reconstructs a consistent population of faint point sources down at least to $10^{-12}$ ph cm${}^{-2}$ s${}^{-1}$. Between $10^{-12}$ ph cm${}^{-2}$ s${}^{-1}$ and $10^{-11}$ ph cm${}^{-2}$ s${}^{-1}$ the 1pPDF measures a number of point sources significantly higher than the ones in the Fermi 4FGL catalog. The robustness of our results brings further support to the attempt of explaining, at least partially, the high-energy tail of the GCE in terms of a population of point sources, likely corresponding to millisecond pulsars.

    ↳ astro-ph.HEhep-phPRD(2024)·23 citations
24. 24*

    $\Lambda$CDM Tensions: Localising Missing Physics through Consistency Checks

    Özgür Akarsu🇹🇷 · Eoin Ó Colgáin🇮🇪 · Anjan A. Sen🇮🇳 · M. M. Sheikh-Jabbari🇮🇷

    $\Lambda$CDM tensions are by definition model dependent; one sees anomalies through the prism of $\Lambda$CDM. Thus, progress towards tension resolution necessitates checking the consistency of the $\Lambda$CDM model to localise missing physics either in redshift or scale. Since the Universe is dynamical and redshift is a proxy for time, it is imperative to first perform consistency checks involving redshift, then consistency checks involving scale, as the next steps to settle the ``systematics versus new physics" debate and foster informed model building. We present a review of the hierarchy of assumptions underlying the $\Lambda$CDM cosmological model and comment on whether relaxing them can address the tensions. We focus on the lowest lying fruit of identifying missing physics through the identification of redshift dependent $\Lambda$CDM model fitting parameters. We highlight recent progress made on $S_8:={\sigma }_8\sqrt{{\Omega }_{\mathrm{m}}/0.3}$ tension and elucidate how similar progress can be made on $H_0$ tension. Our discussions indicate that $H_0$ tension, equivalently a redshift dependent $H_0$, and a redshift dependent $S_8$ imply a problem with background $\Lambda$CDM cosmology.

    ↳ astro-ph.COgr-qchep-phhep-thUniverse(2024)·74 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.