Fri·Jun 28, 2024Friday·June 28, 2024

1. 01*

   Solving the homogeneous Bethe-Salpeter equation with a quantum annealer

   Filippo Fornetti🇮🇹 · Alex Gnech🇺🇸 · Tobias Frederico🇧🇷 · Francesco Pederiva🇮🇹 · Matteo Rinaldi🇮🇹 · Alessandro Roggero🇮🇹 · Giovanni Salme'🇮🇹 · Sergio Scopetta🇮🇹 · Michele Viviani🇮🇹

   The homogeneous Bethe-Salpeter equation (hBSE), describing a bound system in a genuinely relativistic quantum-field theory framework, was solved for the first time by using a D-Wave quantum annealer. After applying standard techniques of discretization, the hBSE, in ladder approximation, can be formally transformed in a generalized eigenvalue problem (GEVP), with two square matrices: one symmetric and the other non symmetric. The latter matrix poses the challenge of obtaining a suitable formal approach for investigating the non symmetric GEVP by means of a quantum annealer, i.e to recast it as a quadratic unconstrained binary optimization problem. A broad numerical analysis of the proposed algorithms, applied to matrices of dimension up to 64, was carried out by using both the proprietary simulated-anneaing package and the D-Wave Advantage 4.1 system. The numerical results very nicely compare with those obtained with standard classical algorithms, and also show interesting scalability features.

   hep-phquant-phPRD(2024)·4 citations
2. 02*

   Two-gluon one-photon vertex in a magnetic field and its explicit one-loop approximation in the intermediate field strength regime

   Alejandro Ayala🇲🇽 · Santiago Bernal-Langarica🇲🇽 · Jorge Jaber-Urquiza🇲🇽 · José Jorge Medina-Serna🇲🇽

   We find the general structure for the two-gluon one-photon vertex in the presence of a constant magnetic field. We show that, when accounting for the symmetries satisfied by the strong and electromagnetic interactions under parity, charge conjugation and gluon interchange, and for gluons and photons on mass-shell, there exist only three possible tensor structures that span the vertex. These correspond to external products of the polarization vectors for each of the particles in the vertex. We also explicitly compute the one-loop approximation to this vertex in the intermediate field strength regime, which is the most appropriate one to describe possible effects of the presence of a magnetic field to enhance photon emission during pre-equilibrium in peripheral relativistic heavy-ion collisions. We show that the most favored direction for the photon to propagate is in the plane transverse to the field, which is consistent with a positive contribution to ${\nu }_2$ and may help to understand the larger than expected elliptic flow coefficient measured in this kind of reactions.

   hep-phnucl-thPRD(2024)·8 citations
3. 03*

   Scattering Neutrinos, Spin Models, and Permutations

   Duff Neill🇺🇸 · Hanqing Liu🇺🇸 · Joshua Martin🇺🇸 · Alessandro Roggero🇮🇹

   We consider a class of Heisenberg all-to-all coupled spin models inspired by neutrino interactions in a supernova with $N$ degrees of freedom. These models are characterized by a coupling matrix that is relatively simple in the sense that there are only a few, relative to $N$, non-trivial eigenvalues, in distinction to the classic Heisenberg spin-glass models, leading to distinct behavior in both the high-temperature and low-temperature regimes. When the momenta of the neutrinos are uniform and random in directions, we can calculate the large-$N$ partition function for the quantum Heisenberg model. In particular, the high-temperature partition function predicts a non-Gaussian density of states, providing interesting counter-examples showing the limits of general theorems on the density of states for quantum spin models. We can repeat the same argument for classical Heisenberg models, also known as rotor models, and we find the high-temperature expansion is completely controlled by the eigenvalues of the coupling matrix, and again predicts non-Gaussian behavior for the density of states as long as the number of eigenvalues does not scale linearly with $N$. Indeed, we derive the amusing fact that these \emph{thermodynamic} partition functions are essentially the generating function for counting permutations in the high-temperature regime. Finally, for the case relevant to neutrinos in a supernova, we identify the low-temperature phase as a unique state with the direction of the momenta of the neutrino dictating its coherent state in flavor-space, a state we dub the "flavor-momentum-locked" state.

   hep-phcond-mat.stat-mechnucl-thquant-phPRResearch(2025)·12 citations
4. 04*

   Unveiling the CP-odd Higgs in a Generalized 2HDM at a Muon Collider

   Nandini Das🇮🇳 · Nivedita Ghosh🇮🇳

   We revisit the generalized two-Higgs-doublet model (2HDM) with a minimally perturbed lepton specific (Type-X) Yukawa sector in context of the muon collider. The model offers a large region of parameter space where it can provide a solution to the observed muon ($g-2$) excess. Specifically the low mass CP odd scalar of this model plays an important role to fit this anomaly. Interestingly, the coupling of the pseudo scalar with the muons is proportional to $\tan \beta$ (the ratio of VEVs of the Higgs doublets) which dominantly controls the one loop and two loop contributions of the muon magnetic moment, therefore it can be probed directly at a muon collider with greater sensitivity in comparison to Large Hadron Collider (LHC). Primarily focusing on a parameter space where muon $g-2$ anomaly is satisfied, we explore the available theoretical and experimental constraints arising from vacuum stability, unitarity, lepton falvour violation (LFV), electroweak precision constraint, B-meson decay and collider experiments on the model. In the parameter space where all these constraints are satisfied, we propose to study the production of the light pseudo-scalar $A$ in association with a photon at a $3$ TeV muon collider. Subsequent decay of $A$ into a $\tau$ pair will produce a striking $l^{+}{l}^{-}\gamma$ plus missing energy signature.

   hep-phhep-exPRD(2025)·7 citations
5. 05*

   Subdiffusion of heavy quark in hot QCD matter by the fractional Langevin equation

   Jai Prakash🇮🇳

   The subdiffusion phenomena are studied for heavy quarks dynamics in the hot QCD matter. My approach aims to provide a more realistic description of heavy quark dynamics through detailed theoretical analyses and numerical simulations, utilizing the fractional Langevin equation framework with the Caputo fractional derivative. I present numerical schemes for the fractional Langevin equation for subdiffusion and calculate the time evolution mean squared displacement and mean squared momentum of the heavy quarks. My results indicate that the mean squared displacements of the heavy quarks for the subdiffusion process deviate from a linear relationship with time. Further, I calculate the normalized momentum correlation function, kinetic energy, and momentum spread. Finally, I show the effect of subdiffusion on experimental observables, the nuclear modification factor.

   hep-phPRC(2024)·5 citations
6. 06*

   Introdução à inferência Bayesiana: técnicas estatísticas para análise de dados de íons pesados relativísticos

   Liner Santos🇧🇷 · Thiago Domingues🇧🇷

   Under extreme conditions of temperature and pressure, it is believed that quarks and gluons (particles that mediate the interaction between quarks) can be "free" in a given volume. This hypothetical phase of matter is called plasma of quarks and gluons, QGP for its acronym in English. It is speculated that it existed in the first moments after the \textit{Big Bang} and that it exists inside Nêutron stars due to the enormous energy density in these places. These conditions of very high temperature and energy density can be reproduced in the laboratory with the collision of heavy ions in an ultra-relativistic regime in accelerators such as the RHIC and the LHC. However, due to the extremely short duration of the QGP phase after the collision, we were unable to directly observe the plasma, only the so-called \textit{final observables}, such as the particles generated by this set of quarks, gluons and energy and the distribution of momentum of these particles. Therefore, mathematical modeling is an essential tool in understanding the behavior of the system, for example, to have an idea of the value of viscosities in this phase.

   hep-phhep-thRevista Brasileira de Fisica, 2024·0 citations
7. 07*

   Radiative decay and axial-vector decay behaviors of octet pentaquark states

   Ya-Ding Lei🇨🇳 · Hao-Song Li🇨🇳

   In this work, we systematically calculate transition magnetic moments, radiative decay widths, and axial-vector coupling constants of octet hidden-charm molecular pentaquark states with different flavor representations in constituent quark model. We discuss the relations between transition magnetic moments and decay widths for pentaquark states. For octet pentaquark states with the $8_{1f}$ and $8_{2f}$ flavor representations, decay widths of the processes $P_{\psi }|{\frac{3}{2}}^{-}{⟩}_{({\frac{1}{2}}^{+}\otimes 1^{-})}\to P_{\psi }|{\frac{1}{2}}^{-}{⟩}_{({\frac{1}{2}}^{+}\otimes 0^{-})}\gamma$ and $P_{\psi }|{\frac{1}{2}}^{-}{⟩}_{({\frac{1}{2}}^{+}\otimes 1^{-})}\to P_{\psi }|{\frac{1}{2}}^{-}{⟩}_{({\frac{1}{2}}^{+}\otimes 0^{-})}\gamma$ are quite close, decay widths of the $P_{\psi }|{\frac{3}{2}}^{-}{⟩}_{({\frac{1}{2}}^{+}\otimes 1^{-})}\to P_{\psi }|{\frac{1}{2}}^{-}{⟩}_{({\frac{1}{2}}^{+}\otimes 1^{-})}\gamma$ process are close to zero, and we notice that the axial-vector coupling constants of the pentaquark states are generally smaller than that of the nucleon.

   hep-phPRD(2024)·4 citations
8. 08*

   Gluonic contributions to the pion parton distribution functions

   Jiangshan Lan🇨🇳 · Chandan Mondal🇨🇳 · Xingbo Zhao🇨🇳 · Tobias Frederico🇧🇷 · James P. Vary🇺🇸

   We investigate the role of a dynamical gluon in the pion within the Basis Light-Front Quantization (BLFQ) framework and compare it with the solution of the Minkowski space Bethe-Salpeter equation (BSE), focusing on contributions beyond the valence sector. We develop a framework to compute the quark-antiquark-gluon component of the pion, starting from its valence light-front wave function. Additionally, the quark and gluon parton distribution functions (PDFs) are derived by considering this higher Fock component in the pion state. The proposed operator, which acts on the valence state to produce the quark-antiquark-gluon component of the pion, is tested against results from BLFQ for its contribution to the quark and gluon PDFs, as well as with results from the BSE. In the BLFQ framework, we identify the effect of dynamical chiral symmetry breaking on the pion structure through the enhancement of the spin-flip matrix element. This enhancement is captured in the $|q\bar{q}g⟩$ component of the light-front wave function and the associated gluon PDF. We explicitly demonstrate an enhancement of the low-$x$ contribution in the quark PDF, which is associated with the large spin-flip matrix element, which also drives the $\pi -\rho$ mass splitting. The proposed framework also enables an exploration of the effect of the dressed gluon mass for a given valence state at the pion scale. We show that when the gluon mass vanishes, departing from the constituent gluon picture, it has a significant impact on the gluon PDF.

   hep-phnucl-thPRD(2025)·14 citations
9. 09*

   Indirect Detection for Higgs Portal Majorana Fermionic Dark Matter

   Naoyuki Haba🇯🇵 · Junpei Ikemoto🇯🇵 · Shimizu Yasuhiro🇯🇵 · Toshifumi Yamada🇯🇵

   We study the $\gamma$-ray signal emitted from dark matter (DM) pair annihilation in the Higgs portal Majorana fermion DM model. In the model, a Majorana fermion DM $\chi$ couples with the Standard Model (SM) Higgs field $H$ through a higher-dimensional term $-\mathcal{L}\supset H^{†}H\bar{\chi }\chi /\Lambda$, where $\Lambda$ is a cutoff scale. The pair annihilation of $\chi$ through the above term produces the Higgs boson and the longitudinal modes of $W,Z$ gauge bosons. The Milky Way dwarf spheroidal satellite galaxies (dSphs) are used as the most promising targets to search for the $\gamma$-ray signal of the model, due to high DM density and lack of astrophysical backgrounds. The {\it Fermi} Large Area Telescope ({\it Fermi}-LAT) is used for the search, for its high sensitivity. In this work, we use 14-year {\it Fermi}-LAT data from 16 dSphs, to constrain the DM pair annihilation cross section for the DM mass range from 125 GeV to 100 TeV.

   hep-phPTEP(2024)·3 citations
10. 10*

    Probing a novel neutral heavy gauge boson within the mono-Z${}^{\prime }$ portal at the HL-LHC

    Ali Muhammad H. H. · El-sayed A. El-dahshan🇪🇬 · S. Elgammal🇪🇬

    This study examines the production of dark matter events alongside a Z${}^{\prime }$ boson decaying through leptonic channels in simulated proton-proton collisions at the Large Hadron Collider. The analysis focuses on collisions at $\sqrt{s}$ = 14 TeV under high-luminosity conditions, corresponding to an integrated luminosity of 1000 fb${}^{-1}$. Using Monte Carlo simulations interpreted within the Effective Field Theory (EFT) framework, the work investigates potential signatures of new physics. In the absence of such phenomena, upper limits are placed on critical EFT parameters, including the theory's cutoff scale and the mass of the Z${}^{\prime }$ boson.

    hep-phChin.J.Phys.(2025)·2 citations
11. 11*

    Refinable modeling for unbinned SMEFT analyses

    Robert Schöfbeck🇦🇹

    We present techniques for estimating the effects of systematic uncertainties in unbinned data analyses at the LHC. Our primary focus is constraining the Wilson coefficients in the standard model effective field theory (SMEFT), but the methodology applies to broader parametric models of phenomena beyond the standard model (BSM). We elevate the well-established procedures for binned Poisson counting experiments to the unbinned case by utilizing machine-learned surrogates of the likelihood ratio. This approach can be applied to various theoretical, modeling, and experimental uncertainties. By establishing a common statistical framework for BSM and systematic effects, we lay the groundwork for future unbinned analyses at the LHC. Additionally, we introduce a novel tree-boosting algorithm capable of learning highly accurate parameterizations of systematic effects. This algorithm extends the existing toolkit with a versatile and robust alternative. We demonstrate our approach using the example of an SMEFT interpretation of highly energetic top quark pair production in proton-proton collisions.

    hep-phhep-exphysics.data-anMach.Learn.Sci.Tech.(2025)·18 citations
12. 12*

    Axion Detection Experiments Meet the Majoron

    Qiuyue Liang🇯🇵 · Xavier Ponce Díaz🇮🇹 · Tsutomu T. Yanagida🇯🇵

    The majoron is a well-motivated light (pseudo-Nambu-Goldstone) boson associated with the spontaneous breaking of a global lepton-number symmetry. In this {\it letter}, we relate the spontaneous breaking scale and its soft-breaking mass by requiring that the majoron is the main component of the dark matter. An electromagnetic-anomalous coupling can be induced by minimally modifying the original majoron model, surprisingly, predicting a parameter region that largely overlaps with the QCD-axion dark matter band. Thus, we expect that axion search experiments meet the majoron.

    hep-phastro-ph.COPRL(2025)·16 citations
13. 13*

    Laboratory constraint on the electric charge of the neutron and the neutrino

    Savely G. Karshenboim🇩🇪

    We revisit constraints on the electric charge of the neutron and neutrino as well as on e_p+e_e. We consider phenomenological constraints based on laboratory study of the electrical neutrality of subatomic, atomic, and molecular species under assumption of the conservation of the electric charge in the beta decay, that relates e_p+e_e, e_n, and e_nu. Some previously published constraints utilized an additional assumption e_nu=0, which we do not. We dismiss a cosmological constraint at the level of 10^-35 e utilized by PDG in their Review of particle properties as a controversial one which makes the laboratory constraints on e_nu dominant. The phenomenological constraints from the laboratory experiments are obtained as e_p+e_e=(0.2\pm2.6)10^-21 e, e_n=(-0.4\pm1.1)10^-21 e, and e_nu=(0.6\pm3.2)10^{-21} e. The ones on e_p+e_e and e_n are at the same level as the PDG constraints, while our e_nu constraint is several orders of magnitude weaker than the controversial cosmological result dominated in the PDG constraint, but several orders of magnitude stronger than the other individual e_nu constraints considered by PDG. We also consider consistency of the phenomenological constraints and the SM. The SM ignores the neutrino mass term and cannot describe the neutrino oscillations which makes it not a complete theory but a part of it. We demonstrate that the condition of the cancellation of the triangle anomaly within the complete theory does not disagree with the phenomenological constraints since different extensions of the SM may produce different additional contributions to the anomaly. In particular, we consider a minimal extension of the SM, where leptons (nu,e) are treated the same ways as quarks, which sets e_p+e_e=0 and allows for numerical strengthening the constraint on e_n and e_nu, which is e_n=-e_nu=(-0.4\pm1.0)10^-21 e.

    hep-phEur.Phys.J.D(2025)·3 citations
14. 14*

    Loop-induced masses for the first two generations with optimum flavour violation

    Gurucharan Mohanta🇮🇳 · Ketan M. Patel🇮🇳

    A mechanism for the masses of third, second, and first generation charged fermions at the tree, 1-loop, and 2-loop levels, respectively, is proposed. The fermionic self-energy corrections that lead to this arrangement are induced through heavy vector bosons of a new gauged flavour symmetry group $G_F$. It is shown that a single Abelian group suffices as $G_F$. Moreover, the gauge charges are optimized to result in relatively smaller flavour violations in processes involving the first and second generation fermions. The scheme is explicitly implemented on the Standard Model fermions in an anomaly-free manner and is shown to be viable with observed charged fermion masses and quark mixings. Constraints from flavour violations dictate the lower limit on the new physics scale in these types of frameworks. Through optimal flavour violation, it is shown that nearly two orders of magnitude improvement can be achieved on the lower limit, leading to the new physics scale $\ge 10^3$ TeV in this case. Further improvements are possible at the cost of the down quark mass deviating more than $3\sigma$ from its value extracted from lattice calculations. Options for inducing tiny masses for light neutrinos are also discussed.

    hep-phhep-thJHEP(2024)·8 citations
15. 15*

    Protonium: Discovery and Prediction

    Bo-Qiang Ma🇨🇳

    The Beijing Spectrometer (BESIII) Collaboration reconstructed the invariant mass of three pairs of positive and negative pions by studying the decay process of charmonium to a photon and three pairs of positive and negative pions. They discovered the resonant structures X(1840) and X(1880), which are interpreted as the predicted proton-antiproton bound states, also known as protonium. This article briefly introduces the experimental discovery processes of these resonant structures and discusses the theoretical explorations inspired by them. The predictions proposed by these theoretical explorations offer a new perspective for studying the nature of these particles and new decay modes. Therefore the collaborative exploration of experiments and theory plays a positive role in deepening understanding of the fundamental laws of nature.

    hep-phhep-exChin.Sci.Bull.(2024)·7 citations
16. 16*

    Study of the ${\Omega }_{ccc}{\Omega }_{ccc}$ and ${\Omega }_{bbb}{\Omega }_{bbb}$ dibaryons in constituent quark model

    Pablo Martín-Higueras🇪🇸 · David R. Entem🇪🇸 · Pablo G. Ortega🇪🇸 · Jorge Segovia🇪🇸 · Francisco Fernández🇪🇸

    Dibaryons are the simplest system in which the baryon-baryon interaction, and hence the underlying quark-quark interaction, can be studied in a clear way. Although the only dibaryon known today is the deuteron (and possibly the $d^{\ast }$), fully heavy dibaryons are good candidates for bound states because in such systems the kinetic energy is small and the high symmetry of the wave function favours binding. In this study, the possible existence of ${\Omega }_{ccc}{\Omega }_{ccc}$ and ${\Omega }_{bbb}{\Omega }_{bbb}$ dibaryons is investigated in the framework of a constituent quark model that satisfactorily describes the deuteron, the $d^{\ast }(2380)$ and the $NN$ interaction. $J^P=0^{+}$ candidates are found in both systems with binding energies of the order of MeV.

    hep-phhep-exhep-latnucl-thPRD(2025)·9 citations
17. 17*

    Probing self-interacting ultrahigh-energy neutrinos with the cosmic 21-cm signal

    Mansi Dhuria🇮🇳 · Bishnu Gupta Teli🇮🇳

    In this study, we investigate the constraints on secret self-interactions of neutrinos by examining the impact of radiative scattering of ultrahigh-energy neutrinos. These neutrinos are produced from the decay of superheavy dark matter and interact with the cosmic neutrino background. We explore how these interactions influence the 21-cm hydrogen signal during the cosmic dark ages and cosmic dawn, periods relatively free from astrophysical uncertainties, providing a clearer signal for studying nonstandard neutrino interactions. By analyzing the global brightness temperature measurements, we constrain the scattering cross section of ultrahigh-energy self-interacting neutrinos, determining the coupling constant $g$ to be within $\sim 10^{-4}$ to $\sim 10^{-3}$ for neutrino energies in the PeV to EeV range. Interestingly, these constraints are more competitive than those from existing astrophysical and collider experiments. As future 21-cm experiments focus on measuring brightness temperature across a wide range of redshifts from the cosmic dark ages to reionization, using the epoch of 21-cm to probe neutrino properties could provide crucial insights into dark matter and neutrino physics.

    hep-phastro-ph.COPRD(2024)·5 citations
18. 18*

    Higher-twist generalized parton distributions of the pion and kaon at zero skewness in the light-cone quark model

    Xiaoyan Luan🇨🇳 · Zhun Lu🇨🇳

    We investigate the higher-twist generalized parton distributions (GPDs) of the pion and kaon at zero skewness by adopting the overlap representation within the light-cone formalism. Using the wave functions of pion and kaon deduced from a light-cone quark model (LCQM), we calculate the twist-3 and twist-4 GPDs $E_2(x,0,t)$, $G_2(x,0,t)$, $F_3(x,0,t)$ and $H_3(x,0,t)$ of valence quark inside the pion and kaon mesons. Numerical results for these higher-twist GPDs are presented. By taking the forward limit, we also present the numerical results for the corresponding twist-3 and twist-4 parton distribution functions (PDFs) $e(x)$ and $f_3(x)$ of pion and kaon. We further study the relations between $e(x)$ or $f_3(x)$ and the twist-2 unpolarized PDF $f_1(x)$.

    hep-phPRD(2024)·7 citations
19. 19*

    X-Ray Constraints on Dark Photon Tridents

    Tim Linden🇸🇪 · Thong T. Q. Nguyen🇸🇪 · Tim M. P. Tait🇺🇸

    Dark photons that are sufficiently light and/or weakly-interacting represent a compelling vision of dark matter. Dark photon decay into three photons, which we call the dark photon trident, can be the dominant channel when the dark photon mass falls below the electron pair threshold and can produce a significant flux of x-rays. We use 16 years of data from INTEGRAL/SPI to constrain sub-MeV dark photon decay, producing new worlds-best constraints on the kinetic mixing parameter for dark photon masses between 61 keV and 1022 keV, and comment on the potential for future x-ray observatories to discover the trident decay process.

    hep-phastro-ph.HEPRD(2025)·33 citations
20. 20*

    Graviton- and Inflaton-mediated Dark Matter Production after Large Field Polynomial Inflation

    Nicolás Bernal🇦🇪 · Julia Harz🇩🇪 · Martin A. Mojahed🇩🇪 · Yong Xu🇩🇪

    Polynomial inflation is a simple cosmological scenario, which fits the cosmic microwave background data well. It provides testable predictions for the tensor-to-scalar ratio and the running of the spectral index. In this work, we investigate the production of Dirac dark matter (DM) within the framework of large-field polynomial inflation. We study all relevant production channels including $i$) non-thermal production through inflaton decays and scatterings, and $ii$) thermal production from scattering of standard model particles mediated by inflatons and gravitons. In contrast to small-field polynomial inflation, where inflaton decay dominates DM production, we find that graviton-mediated processes can be dominant in the large-field scenario. For DM lighter than the inflaton, we demonstrate that the interplay between graviton- and inflaton-mediated production channels give rise to non-trivial relations between the DM mass and the reheating temperature required to account for the DM relic abundance.

    hep-phastro-ph.COPRD(2025)·17 citations
21. 21*

    Bringing Peccei-Quinn Mechanism Down to Earth

    Hooman Davoudiasl🇺🇸 · Marvin Schnubel🇺🇸

    It is conventionally assumed that the physics underlying the Peccei-Quinn (PQ) mechanism for addressing the strong CP problem is at very high energies, orders of magnitude above the weak scale. However, this may not be the case in general and the associated PQ boson $\varphi$, besides the signature state, {\it i.e.} the ultralight axion $a$, may emerge well below the weak scale. We consider this possibility and examine some of the conditions for its viability. The example model proposed here may also provide the requisite Standard Model Higgs mass parameter, without invoking new scalars above the GeV scale. The corresponding parameter space can maintain {\it finite naturalness} against quantum corrections. This scenario, depending on choice of parameters, can potentially be constrained by flavor data. We point out that the current mild excess in $B^{+}\to K^{+}\nu \bar{\nu }$, reported by the Belle II experiment, could be explained in this setup as $B^{+}\to K^{+}\varphi$ and $B^{+}\to K^{+}a$, with both $\varphi$ and $a$ escaping the detector as missing energy. For a sufficiently heavy PQ boson, in the GeV regime, one can separate these two contributions, due to the difference in $K^{+}$ momenta. In this case, the axion may also affect lighter meson, {\it e.g.} kaon, decays while $\varphi$ would not be a kinematically allowed final state.

    hep-phPRD(2024)·8 citations
22. 22*

    Nonleptonic $B$-meson decays to next-to-next-to-leading order

    Manuel Egner🇩🇪 · Matteo Fael🇨🇭 · Kay Schönwald🇨🇭 · Matthias Steinhauser🇩🇪

    We compute next-to-next-to-leading order QCD corrections to the partonic processes $b\to c\bar{u}d$ and $b\to c\bar{c}s$, which constitute the dominant decay channels in standard model predictions for $B$-meson lifetimes within the heavy quark expansion. We consider the contribution from the four-quark operators $O_1$ and $O_2$ in the $\Delta B=1$ effective Hamiltonian. The decay rates are obtained from the imaginary parts of four-loop propagator-type diagrams. We compute the corresponding master integrals using the "expand and match" approach which provides semi-analytic results for the physical charm and bottom quark masses. We show that the dependence of the decay rate on the renormalization scale is significantly reduced after including the next-to-next-to-leading order corrections. Furthermore, we compute next-to-next-to-leading order corrections to the Cabibbo-Kobayashi-Maskawa-suppressed decay channels $b\to u\bar{c}s$ and $b\to u\bar{u}d$.

    hep-phJHEP(2024)·20 citations
23. 23*

    Theoretical point of view on Cabibbo angle anomaly

    Teppei Kitahara🇯🇵

    We present the current situation of the determinations of the first-row CKM components and show the Cabibbo angle anomaly corresponding to a deficit in the first-row CKM unitarity condition at the $3\sigma$ level. In this contribution, we show two new physics interpretations: heavy vector-like quark models and a MeV scale sterile neutrino models. The super tau-charm facility will directly probe the other CKM unitarity conditions related to $V_{cd}$.

    hep-phhep-exInt.J.Mod.Phys.A(2024)·5 citations
24. 24*

    Physical-mass calculation of $\rho (770)$ and $K^{\ast }(892)$ resonance parameters via $\pi \pi$ and $K\pi$ scattering amplitudes from lattice QCD

    Peter Boyle🇺🇸 · Felix Erben🇨🇭 · Vera Gülpers🇬🇧 · Maxwell T. Hansen🇬🇧 · Fabian Joswig🇬🇧 · Nelson Pitanga Lachini🇬🇧 · Michael Marshall🇬🇧 · Antonin Portelli🇬🇧

    We present our study of the $\rho (770)$ and $K^{\ast }(892)$ resonances from lattice quantum chromodynamics (QCD) employing domain-wall fermions at physical quark masses. We determine the finite-volume energy spectrum in various momentum frames and obtain phase-shift parameterizations via the Lüscher formalism, and as a final step the complex resonance poles of the $\pi \pi$ and $K\pi$ elastic scattering amplitudes via an analytical continuation of the models. By sampling a large number of representative sets of underlying energy-level fits, we also assign a systematic uncertainty to our final results. This is a significant extension to data-driven analysis methods that have been used in lattice QCD to date, due to the two-step nature of the formalism. Our final pole positions, $M+i\Gamma /2$, with all statistical and systematic errors exposed, are $M_{K^{\ast }}=893(2)(8)(54)(2)\mathrm{MeV}$ and ${\Gamma }_{K^{\ast }}=51(2)(11)(3)(0)\mathrm{MeV}$ for the $K^{\ast }(892)$ resonance and $M_{\rho }=796(5)(15)(48)(2)\mathrm{MeV}$ and ${\Gamma }_{\rho }=192(10)(28)(12)(0)\mathrm{MeV}$ for the $\rho (770)$ resonance. The four differently grouped sources of uncertainties are, in the order of occurrence: statistical, data-driven systematic, an estimation of systematic effects beyond our computation (dominated by the fact that we employ a single lattice spacing), and the error from the scale-setting uncertainty on our ensemble.

    ↳ hep-lathep-phPRD(2025)·22 citations
25. 25*

    Light and strange vector resonances from lattice QCD at physical quark masses

    Peter Boyle🇺🇸 · Felix Erben🇨🇭 · Vera Gülpers🇬🇧 · Maxwell T. Hansen🇬🇧 · Fabian Joswig🇬🇧 · Nelson Pitanga Lachini🇬🇧 · Michael Marshall🇬🇧 · Antonin Portelli🇬🇧

    We present the first ab initio calculation at physical quark masses of scattering amplitudes describing the lightest pseudoscalar mesons interacting via the strong force in the vector channel. Using lattice quantum chromodynamics, we postdict the defining parameters for two short-lived resonances, the $\rho (770)$ and $K^{\ast }(892)$, which manifest as complex energy poles in $\pi \pi$ and $K\pi$ scattering amplitudes, respectively. The calculation proceeds by first computing the finite-volume energy spectrum of the two-hadron systems, and then determining the amplitudes from the energies using the Lüscher formalism. The error budget includes a data-driven systematic error, obtained by scanning possible fit ranges and fit models to extract the spectrum from Euclidean correlators, as well as the scattering amplitudes from the latter. The final results, obtained by analytically continuing multiple parameterizations into the complex energy plane, are $M_{\rho }=796(5)(50)\mathrm{MeV}$, ${\Gamma }_{\rho }=192(10)(31)\mathrm{MeV}$, $M_{K^{\ast }}=893(2)(54)\mathrm{MeV}$ and ${\Gamma }_{K^{\ast }}=51(2)(11)\mathrm{MeV}$, where the subscript indicates the resonance and $M$ and $\Gamma$ stand for the mass and width, respectively, and where the first bracket indicates the statistical and the second bracket the systematic uncertainty.

    ↳ hep-lathep-phPRL(2025)·24 citations
26. 26*

    Interacting ultralight dark matter and dark energy and fits to cosmological data in a field theory approach

    Amin Aboubrahim🇩🇪 · Pran Nath🇺🇸

    The description of dark matter as a pressure-less fluid and of dark energy as a cosmological constant, both minimally coupled to gravity, constitutes the basis of the concordance $\Lambda \text{CDM}$ model. However, the concordance model is based on using equations of motion directly for the fluids with constraints placed on their sources, and lacks an underlying Lagrangian. In this work, we propose a Lagrangian model of two spin zero fields describing dark energy and dark matter with an interaction term between the two along with self-interactions. We study the background evolution of the fields as well as their linear perturbations, suggesting an alternative to $\Lambda$CDM with dark matter and dark energy being fundamental dynamical fields. The parameters of the model are extracted using a Bayesian inference tool based on multiple cosmological data sets which include those of Planck (with lensing), BAO, Pantheon, SH0ES, and WiggleZ. Using these data, we set constraints on the dark matter mass and the interaction strengths. Furthermore, we find that the model is able to alleviate the Hubble tension for some data sets while also resolving the $S_8$ tension.

    ↳ astro-ph.COhep-phJCAP(2024)·31 citations
27. 27*

    The AMS-02 cosmic ray deuteron flux is consistent with a secondary origin

    Qiang Yuan (PMO, USTC)🇨🇳 · Yi-Zhong Fan (PMO, USTC)🇨🇳

    The recent measurements of cosmic ray deuteron fluxes by AMS-02 show that the rigidity dependence of deuterons is similar with that of protons but flatter than ${}^3$He, which has been attributed to the existence of primary deuterons with abundance much higher than that from the Big Bang nucleosynthesis. The requirement of highly deuteron-abundant sources imposes a serious challenge on the modern astrophysics since there is no known process to produce a large amount of deuterons without violating other constraints \citep{1976Natur.263..198E}. In this work we demonstrate that the fragmentation of heavy nuclei up to nickel plays a crucial role in shaping/enhancing the spectrum/flux of the cosmic ray deuterons. Based on the latest cosmic ray data, the predicted secondary fluxes of deuterons and ${}^3$He are found to be reasonably consistent with the AMS-02 measurements and a primary deuteron component is not needed. The observed differences between the spectra of D and ${}^3$He, as well as those between the D/${}^4$He (D/p) and ${}^3$He/${}^4$He (${}^3$He/p) flux ratios, measured in the rigidity space, is probably due to the kinetic-energy-to-rigidity conversion and the solar modulation, given different charge-to-mass ratios of D and ${}^3$He. More precise measurements of the fragmentation cross sections of various nuclei to produce deuterons, tritons, and ${}^3$He in a wide energy range will be very helpful in further testing the secondary origin of cosmic ray deuterons.

    ↳ astro-ph.HEhep-phApJL(2024)·6 citations
28. 28*

    A Superfluid Dark Matter Cosmic String Wake

    Aline Favero🇨🇦 · Robert Brandenberger🇨🇦

    We study the effects of superfluid dark matter on the structure of a cosmic string wake, considering both the effects of regular and quantum pressure terms. We consider the total fluid to consist of a combination of baryons and dark matter. Hence, we are also able to study the effects of superfluid dark matter on the distribution of baryons inside the wake. We focus on parameter values for the superfluid dark matter which allow a MONDian explanation of galaxy rotation curves.

    ↳ astro-ph.COgr-qchep-phhep-thEPJC(2025)·4 citations
29. 29*

    Ultrahigh-energy neutrino searches using next-generation gravitational wave detectors at radio neutrino detectors: GRAND, IceCube-Gen2 Radio, and RNO-G

    Mainak Mukhopadhyay🇺🇸 · Kumiko Kotera🇫🇷 · Stephanie Wissel🇺🇸 · Kohta Murase🇺🇸 · Shigeo S. Kimura🇯🇵

    Binary neutron star (BNS) mergers can be sources of ultrahigh-energy (UHE) cosmic rays and potential emitters of UHE neutrinos. The upcoming and current radio neutrino detectors like the Giant Radio Array for Neutrino Detection (GRAND), IceCube-Gen2 Radio, and the Radio Neutrino Observatory in Greenland (RNO-G) are projected to reach the required sensitivities to search for these neutrinos. In particular, in conjunction with the next-generation of gravitational wave (GW) detectors like Cosmic Explorer (CE) and Einstein Telescope (ET), GW-triggered stacking searches can be performed with the UHE neutrino detectors. In this work, we explore the prospects of such searches by implementing in our analysis an upper distance limit based on the sky-localization capabilities of the GW detectors from which meaningful triggers can be collected. We find that if each GW burst is associated with a total isotropic-equivalent energy of $\sim 10^{50}-10^{51}$ erg emitted in UHE neutrinos, along with a corresponding beaming fraction of $1$%, GRAND and IceCube-Gen2 Radio have a large probability ($\sim 99$%) to detect a coincident neutrino event using the joint combination of CE+ET in a timescale of less than 15 years of operation for our fiducial choice of parameters. In case of nondetections, the parameter spaces can be constrained at $3\sigma$ level in similar timescales of operation. We also highlight and discuss the prospects of such joint radio neutrino detector network, their importance, and their role in facilitating synergic GW and neutrino observations in the next era of multimessenger astrophysics.

    ↳ astro-ph.HEgr-qchep-phPRD(2024)·13 citations
30. 30*

    Dark matter coupled to radiation: Limits from the Milky Way satellites

    Wendy Crumrine🇺🇸 · Ethan O. Nadler🇺🇸 · Rui An🇺🇸 · Vera Gluscevic🇺🇸

    Interactions between dark matter (DM) and relativistic particles at early times suppress structure formation on small scales. In particular, the scattering process transfers heat and momentum from radiation to DM, ultimately reducing the abundance of low-mass DM halos and the dwarf galaxies they host. Herein, we derive limits on DM-photon and DM-neutrino scattering cross section using the Milky Way satellite galaxy population. We consider temperature-independent interactions parameterized by DM mass ($m_{\chi }$) and DM-radiation interaction cross section (${\sigma }_{\chi \text{-}i}$, where $i$ represents the target species). By requiring that the linear matter power spectra be strictly less suppressed than in the case of a thermal-relic warm DM cutoff, we derive the following $95\%$ upper limits at $m_{\chi }=1$ MeV: ${\sigma }_{\chi \text{-}\gamma }<1.98\times 10^{-38}{\text{cm}}^2$ and ${\sigma }_{\chi \text{-}\nu }<3.16\times 10^{-38}{\text{cm}}^2$. Our bounds on ${\sigma }_{\chi \text{-}i}$ depend linearly on $m_{\chi }$ for $m_{\chi }\gtrsim 1\mathrm{MeV}$ and improve upon previous limits by 1 order of magnitude. The mass dependence of our limit approaches $m_{\chi }^3$ at lower masses due to the effects of DM sound speed; at $m_{\chi }=100\mathrm{keV}$, we arrive at an upper limit 3 orders of magnitude more stringent than achieved in previous explorations. Upcoming dwarf galaxy surveys will further improve the sensitivity of similar analyses, complementing laboratory and indirect detection searches for DM-radiation interactions.

    ↳ astro-ph.COhep-phPRD(2025)·21 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.