Wed·Apr 24, 2024Wednesday·April 24, 2024

1. 01*

   Inflaton decay in No-Scale Supergravity and Starobinsky-like models

   Yohei Ema🇺🇸 · Marcos A. G. Garcia🇲🇽 · Wenqi Ke🇺🇸 · Keith A. Olive🇺🇸 · Sarunas Verner🇺🇸

   We consider the decay of the inflaton in Starobinsky-like models arising from either an $R+R^2$ theory of gravity or $N=1$ no-scale supergravity models. If Standard Model matter is simply introduced to the $R+R^2$ theory, the inflaton (which appears when the theory is conformally transformed to the Einstein frame) couples to matter predominantly in Standard Model Higgs kinetic terms. This will typically lead to a reheating temperature of $\sim 3\times 10^9$~GeV. However, if the Standard Model Higgs is conformally coupled to curvature, the decay rate may be suppressed and vanishes for a conformal coupling $\xi =1/6$. Nevertheless, inflaton decays through the conformal anomaly leading to a reheating temperature of order $10^8$~GeV. The Starobinsky potential may also arise in no-scale supergravity. In this case, the inflaton decays if there is a direct coupling of the inflaton to matter in the superpotential or to gauge fields through the gauge kinetic function. We also discuss the relation between the theories and demonstrate the correspondence between the no-scale models and the conformally coupled $R+R^2$ theory (with $\xi =1/6$).

   hep-phastro-ph.COhep-thUniverse(2024)·16 citations
2. 02*

   SUBA-Jet: a new Model for Jets in Heavy Ion Collisions

   Iurii Karpenko🇨🇿 · Alexander Lind🇫🇷 · Martin Rohrmoser🇵🇱 · Joerg Aichelin🇫🇷 · Pol-Bernard Gossiaux🇫🇷

   We present a new model for jet quenching in a quark gluon plasma (QGP). The jet energy loss has two steps. The initial jet parton with a high virtuality loses energy by a perturbative vacuum parton shower modified by medium interactions until it becomes on shell. Subsequent energy loss originates from elastic and radiative collisions with the medium constituents. Coherency of the radiative collisions is achieved by starting with virtual gluons that act as field dressing of the initial jet parton. These are formed according to a Gunion-Bertsch seed. The QCD version of the LPM effect is obtained by increasing the phase of the virtual gluons through elastic scatterings with the medium. Above a phase threshold, the virtual gluons will be formed and can produce coherent radiation themselves. The model has been implemented in a Monte Carlo code and is validated by successfully reproducing the BDMPS-Z prediction for the energy spectrum of radiated gluons in a static medium. Results for the more realistic case, in which the assumptions of the BDMPS-Z approach are released, are also shown. We investigate the influence of various parameters on the energy spectrum and the transverse momentum distribution, such as the in-medium quark masses, the energy transfer in the recoil process, and the phase accumulation criteria, especially for low and intermediate energy gluons.

   hep-phJHEP(2025)·5 citations
3. 03*

   Streamlined jet tagging network assisted by jet prong structure

   A. Hammad🇯🇵 · Mihoko M. Nojiri🇯🇵

   Attention-based transformer models have become increasingly prevalent in collider analysis, offering enhanced performance for tasks such as jet tagging. However, they are computationally intensive and require substantial data for training. In this paper, we introduce a new jet classification network using an MLP mixer, where two subsequent MLP operations serve to transform particle and feature tokens over the jet constituents. The transformed particles are combined with subjet information using multi-head cross-attention so that the network is invariant under the permutation of the jet constituents. We utilize two clustering algorithms to identify subjets: the standard sequential recombination algorithms with fixed radius parameters and a new IRC-safe, density-based algorithm of dynamic radii based on HDBSCAN. The proposed network demonstrates comparable classification performance to state-of-the-art models while boosting computational efficiency drastically. Finally, we evaluate the network performance using various interpretable methods, including centred kernel alignment and attention maps, to highlight network efficacy in collider analysis tasks.

   hep-phJHEP(2024)·17 citations
4. 04*

   LHC di-lepton searches for $Z^{\prime }$ bosons which explain measurements of $b\to s{l}^{+}{l}^{-}$ transitions

   Ben Allanach (University of Cambridge)🇬🇧

   Several current measurements of $b\to s{l}^{+}{l}^{-}$ processes are in tension with Standard Model predictions, whereas others (e.g.\ $R_K$ and $R_{K^{\ast }}$) are in reasonable agreement with them. We examine some recent $Z^{\prime }$ models that fit the data as a whole appreciably better than does the Standard Model, confronting the models with ATLAS resonance searches in the $e^{+}{e}^{-}$ and ${\mu }^{+}{\mu }^{-}$ channels. Both channels constrain the models; we find that the searches rule out less than one fifth of the allowed range of $M_{Z^{\prime }}$. We estimate that the HL-LHC can roughly double the current sensitivity in $M_{Z^{\prime }}$, but covering the whole parameter space would take a more powerful machine, such as a 100 TeV $pp$ collider.

   hep-phhep-exPLB(2024)·13 citations
5. 05*

   Investigating $\Xi$ resonances from pentaquark perspective

   Ye Yan🇨🇳 · Qi Huang🇨🇳 · Xinmei Zhu🇨🇳 · Hongxia Huang🇨🇳 · Jialun Ping🇨🇳

   We have investigated the $qss\bar{q}q$ ($q=u$ or $d$) system to find possible pentaquark explanations for the $\Xi$ resonances. The bound state calculation is carried out within the framework of the quark delocalization color screening model. The scattering processes are also studied to examine the possible resonance states. The current results indicate that the $\Xi (1950)$ can be interpreted as $\Lambda {\bar{K}}^{\ast }$ state with $J^P=1/2^{-}$. Three states are identified that match the $\Xi (2250)$, which are ${\Sigma }^{\ast }{\bar{K}}^{\ast }$ state with $J^P=3/2^{-}$, ${\Sigma }^{\ast }{\bar{K}}^{\ast }$ state with $J^P=5/2^{-}$, and ${\Xi }^{\ast }\rho$ state with $J^P=5/2^{-}$. This may explain the conflicting experimental values for the width of the $\Xi (2250)$. A new $\Xi$ resonance is predicted, whose mass and width are 2066--2079 MeV and 186--189 MeV, respectively. These results contribute to understanding the nature of the $\Xi$ resonances and to the future search for new $\Xi$ resonances. Moreover, it is meaningful to further investigate the $\Xi$ resonances from an unquenched picture on the basis of pentaquark investigation.

   hep-phnucl-thPRD(2024)·8 citations
6. 06*

   Exploring interference effects between two ALP effective operators at the LHC

   Kingman Cheung🇹🇼 · Chih-Ting Lu🇨🇳 · C.J. Ouseph🇹🇼 · Priyanka Sarmah🇹🇼

   We observe that most studies of axion-like particle (ALP) production channels at the Large Hadron Collider (LHC) focus on a single type of ALP operator for each process in the effective field theory framework. In this work, we propose an alternative approach that considers two or more types of relevant ALP effective operators together in some specific ALP production channels and study their interference effects. Using the $pp\to tja$ process with $a\to \gamma \gamma$ as an example, we show that this approach allows us to constrain the ALP interactions with both the $W$ boson and the top quark, as well as their interference in a single process. For the final state with two isolated photons and a top quark decaying semi-leptonically, we predict that the future bounds on the ALP decay constant can reach around $f_a\sim 10(20)$ TeV for $25$ GeV $<M_a<100$ GeV at the LHC with 300 (3000) fb${}^1$ luminosity.

   hep-phJHEP(2024)·7 citations
7. 07*

   Probing bottom-associated production of a TeV scale scalar decaying to a top quark and dark matter at the LHC

   Amandeep Kaur Kalsi🇮🇳 · Teruki Kamon🇺🇸 · Seulgi Kim🇰🇷 · Jason S.H. Lee🇰🇷 · Denis Rathjens🇺🇸 · Youn Jung Roh🇰🇷 · Adrian Thompson🇺🇸 · Ian James Watson🇰🇷

   A minimal non-thermal dark matter model that can explain both the existence of dark matter and the baryon asymmetry in the universe is studied. It requires two color-triplet, iso-singlet scalars with $\mathcal{O}$(TeV) masses and a singlet Majorana fermion with a mass of $\mathcal{O}$(GeV). The fermion becomes stable and can play the role of the dark matter candidate. We consider the fermion to interact with a top quark via the exchange of QCD-charged scalar fields coupled dominantly to third generation fermions. The signature of a single top quark production associated with a bottom quark and large missing transverse momentum opens up the possibility to search for this type of model at the LHC in a way complementary to existing monotop searches.

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

   Monte Carlo evaluation of divergent one-loop integrals without contour deformation

   Roberto Pittau🇪🇸

   Reference [1] introduces a method for computing numerically four-dimensional multi-loop integrals without performing an explicit analytic contour deformation around threshold singularities. In this paper, we extend such a technique to massless scalar one-loop integrals regularized in the framework of dimensional regularization. A two-loop example is also discussed.

   hep-phhep-thEPJC(2024)·3 citations
9. 09*

   Chiral-vacuum excited replicae in QCD modeling

   Eduardo Garnacho-Velasco🇩🇪 · Pedro J. de A. Bicudo🇵🇹 · J. Emilio F. T. Ribeiro🇵🇹 · Felipe J. Llanes-Estrada🇪🇸 · Lucas Pérez Molina🇪🇸 · Victor Serrano Herreros🇪🇸 · Jorge Vallejo Fernández🇪🇸

   We present a detailed study of the Bardeen-Cooper-Schrieffer (BCS) gap equation ``replicae'' or excited vacuum states, orthogonal to the ground-state one, in the chiral-quark sector of the Hamiltonian Coulomb-gauge model of chromodynamics. Analyzing the number of negative eigenmodes of the energy density's Hessian we believe that we have identified all of the (negative energy-density) vacua of this nonlinear system, namely the ground BCS state and two (or one) replicae for slightly massive (or massless) quarks, given the interaction strength typical of the strong interactions. The meson spectrum over each of the replicae looks similar, so the differences are not significant enough given model uncertainties, but matrix elements are more sensitive and allow to distinguish them. We propose to look for such excited vacua in lattice gauge theory by trying to identify excitations with scalar quantum numbers which have energies proportional to the lattice volume (unlike conventional mesons for which the mass stabilizes to a constant upon taking the infinite volume limit).

   hep-phhep-latPRD(2024)·2 citations
10. 10*

    Asymmetric self-interacting dark matter with a canonical seesaw model

    Debasish Borah🇮🇳 · Satyabrata Mahapatra🇰🇷 · Partha Kumar Paul🇮🇳 · Narendra Sahu🇮🇳 · Prashant Shukla🇮🇳

    We study the possibility of generating dark matter (DM) and baryon asymmetry of the Universe (BAU) simultaneously in an asymmetric DM framework, which also alleviates the small-scale structure issues of cold DM. While the thermal relic of such self-interacting DM remains under-abundant due to efficient annihilation into light mediators, a nonzero asymmetry in the dark sector can lead to the survival of the required DM in the Universe. The existence of a light mediator leads to the required self-interactions of DM at small scales while keeping DM properties similar to cold DM at large scales. It also ensures that the symmetric DM component annihilates away, leaving the asymmetric part in the spirit of cogenesis. The particle physics implementation is done in canonical seesaw models of light neutrino mass, connecting it to the origin of DM and BAU. In particular, we consider type-I and type-III seesaw origin of neutrino mass for simplicity and minimality of the field content. We show that the desired self-interactions and relic of DM together with BAU while satisfying relevant constraints lead to strict limits on DM mass $\mathcal{O}(\mathrm{GeV})\lesssim M_{\mathrm{DM}}\lesssim 460$ GeV. In spite of being a high-scale seesaw, the models remain verifiable in different experiments, including direct and indirect DM searches as well as colliders.

    hep-phastro-ph.COPRD(2024)·26 citations
11. 11*

    Particle Swarm Optimization Based Analysis to Unlocking the Neutrino Mass Puzzle using $A_4\times Z_3\times Z_{10}$ Flavor Symmetry

    M.W. Aslam · A.A. Zafar · M.N. Aslam · A.A Bhatti · T. Hussain · M. Iqbal

    New research has highlighted a shortfall in the Standard Model (SM) because it predicts neutrinos to have zero mass. However, recent experiments on neutrino oscillation have revealed that the majority of neutrino parameters indeed indicate their significant mass. In response, scientists are increasingly incorporating discrete symmetries alongside continuous ones for better justification of observed patterns of neutrino mixing. In this study, we have examined a model within $A_4\times Z_3\times Z_{10}$ symmetry to estimate the neutrino masses using particle swarm optimization technique for both mass hierarchy of neutrino. This model employed a hybrid seesaw mechanism, a combination of seesaw mechanism of type-I and type-II, to establish the effective Majorana neutrino mass matrix. After calculating the mass eigenvalues and lepton mixing matrix upto second order perturbation theory in this framework, this study seeks to investigate the scalar potential for vacuum expectation values (VEVs), optimize the parameters, $U_{PMNS}$ matrix, neutrino masses: $|{m_1^{\prime }}^N|=0.0292794-0.0435082eV$, $|{m_2^{\prime }}^N|=1.78893\times 10^{-18}-0.0293509eV$, $|{m_3^{\prime }}^N|=0.0307414-0.0471467eV$, $|{m_1^{\prime }}^I|=0.00982013-0.0453623eV$, $|{m_2^{\prime }}_{|}^I=0.0379702-0.0471197eV$, and $|{m_3^{\prime }}^I|=0.0122063-0.027544eV$, effective neutrino mass parameters: $⟨m_{ee}{⟩}^N=(0.170-3.93)\times 10^{-2}eV$, $⟨m_{\beta }{⟩}^N=(0.471-1.39)\times 10^{-2}eV$, $⟨m_{ee}{⟩}^I=(1.85-4.55)\times 10^{-2}eV$ and $⟨m_{\beta }{⟩}^I=(2.26-4.56)\times 10^{-2}eV$, are predicted for both mass hierarchy through particle swarm optimization (PSO), showing strong agreement with recent experimental findings.

    hep-phSci.Rep.(2025)·5 citations
12. 12*

    Complete CP-eigen Bases of Meson-Baryon Chiral Lagrangian up to $p^5$-order

    Chuan-Qiang Song🇨🇳 · Hao Sun🇨🇳 · Jiang-Hao Yu🇨🇳

    Chiral perturbation theory describes the low energy dynamics of mesons and baryons in terms of the nonlinear Goldstone boson and fermion degrees of freedom. Through the Young tensor technique, we construct the on-shell operator bases for the meson-baryon system up to $p^5$-order, using the chiral dimension power counting and heavy baryon expansion. For the Lorentz structure, additional treatments on off-shell external sources and operators with higher derivatives are necessarily considered, while for the internal structure, the invariant tensor basis is converted into the trace basis equivalently, and Cayley-Hamilton relations are utilized to classify different CP eigen-operators. Finally we present the complete operator set of $C$+$P$+, $C$+$P$-, $C$-$P$+, and $C$-$P$- eigen-operators at the $p^5$-order, and obtain the operator counting from the Hilbert series.

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

    Decay $B_c^{+}\to D_{(s)}^{(\ast )+}{\ell }^{+}{\ell }^{-}$ within covariant confined quark model

    Mikhail A. Ivanov🇷🇺 · Jignesh N. Pandya🇮🇳 · Pietro Santorelli🇮🇹 · Nakul R. Soni🇮🇹

    We study the rare semileptonic decays of $B_c$ mesons within the effective field theoretical framework of covariant confined quark model. The transition form factors corresponding to $B_c^{+}\to D^{(\ast )+}$ and $B_c^{+}\to D_s^{(\ast )+}$ are computed in the entire $q^2$ range. Using form factors, we compute the branching fractions and compare them with the available theoretical results. We also compute various physical observables such as forward-backward asymmetry, longitudinal and transverse polarizations as well as clean angular observables.

    hep-phPRD(2024)·5 citations
14. 14*

    Resummation of combined QCD-electroweak effects in Drell Yan lepton-pair production

    Luca Buonocore🇨🇭 · Luca Rottoli🇨🇭 · Paolo Torrielli🇮🇹

    We consider neutral- and charged-current Drell Yan lepton-pair production at hadron colliders, and include dominant classes of electroweak and mixed QCD-electroweak corrections to all orders in perturbation theory. The accurate description of these physical effects is vital for a precise determination of fundamental Standard Model parameters, such as the $W$-boson mass and the electroweak mixing angle, as well as for a solid assessment of the associated theoretical uncertainties. Our state-of-the-art resummation reaches next-to-leading-logarithmic accuracy in both the electroweak and the mixed QCD-electroweak perturbative expansions, including constant terms at first order beyond Born level in both couplings, i.e. at order $\alpha$ and ${\alpha }_s\alpha$. These effects are incorporated on top of QCD predictions at next-to-next-to-next-to-leading-logarithmic accuracy, which include constant terms at third order in the strong coupling. Our results retain, for the first time at this accuracy, full dependence on the kinematics of the final-state leptons, thereby enabling a realistic comparison with experimental analyses at the differential level in presence of fiducial cuts. We present a phenomenological analysis of the impact of electroweak corrections in relevant observables at the LHC. We find visible shape distortions in resummation-dominated kinematical regions with respect to pure-QCD predictions, highlighting the importance of a complete description, not limited to QCD, for precision Drell Yan physics.

    hep-phhep-exJHEP(2024)·12 citations
15. 15*

    Virtual QCD corrections to $gg\to ZZ$: top-quark loops from a transverse-momentum expansion

    Giuseppe Degrassi🇮🇹 · Ramona Gröber🇮🇹 · Marco Vitti🇩🇪

    We present the virtual corrections due to the top-quark loops for the process $gg\to ZZ$ at next-to-leading order in QCD. The associated two-loop box diagrams are computed using a small-transverse-momentum expansion. Our results are then merged with those available in the complementary energy region, obtained via a high-energy expansion, in order to provide an analytic result that is valid in the whole phase space. The results presented allow for an efficient modelling of the signal--background interference as well as the irreducible background in off-shell Higgs production.

    hep-phJHEP(2024)·10 citations
16. 16*

    $1/Q^2$ power corrections to TMD factorization for Drell-Yan hadronic tensor

    Ian Balitsky🇺🇸

    I calculate $\frac{1}{Q^2}$ power corrections to unpolarized Drell-Yan hadronic tensor for electromagnetic (EM) current at large $N_c$ and demonstrate the EM gauge invariance at this level.

    hep-phNPB(2024)·7 citations
17. 17*

    QCD topology and axion properties in an isotropic hot and dense medium

    Hong-Fang Gong🇨🇳 · Qi Lu🇨🇳 · Zhen-Yan Lu🇨🇳 · Lu-Meng Liu🇨🇳 · Xun Chen🇨🇳 · Shu-Peng Wang🇨🇳

    We study the QCD topology and axion properties at finite temperature and chemical potential in the framework of the two-flavor Nambu$-$Jona-Lasinio model. We find that the behaviors of the two lowest cumulants of the QCD topological charge distribution and axion properties are highly sensitive to the critical behavior of the chiral phase transition. In particular, the topological susceptibility and the axion mass follow the response of the chiral condensate to temperature and chemical potential, showing that both quantities decrease monotonically with the increment of temperature and/or chemical potential. However, it is important to note that the normalized fourth cumulant behaves differently depending on the temperature. At low temperatures, it is a non-monotonic function of the chemical potential, while at high temperatures, it monotonically decreases. Additionally, its value invariably approaches the asymptotic value of $b_2^{\text{inst }}=-1/12$, predicted by the dilute instanton gas model. We also observe that with the increase in chemical potential at relatively low temperatures, the axion self-coupling constant exhibits a sharp peak around the critical point, which can even be more than twice its vacuum value. After that, the self-coupling drops sharply to a much lower value than its vacuum value, eventually approaching zero in the high chemical potential limit. The finding that the axion self-coupling constant is significantly enhanced in high-density environments near the chiral phase transition could lead to the creation or enhancement of an axion Bose-Einstein condensate in compact astrophysical objects.

    hep-phastro-ph.HEEPJC(2024)·10 citations
18. 18*

    Estimating Longitudinal Polarization of $\Lambda$ and $\bar{\Lambda }$ Hyperons at Relativistic Energies using Hydrodynamic and Transport models

    Bhagyarathi Sahoo🇮🇳 · Captain R. Singh🇮🇳 · Raghunath Sahoo🇮🇳

    The global and local spin polarization measurements of $\Lambda$ ($\bar{\Lambda }$) hyperons by STAR and ALICE Collaborations open up an immense interest in investigating the spin polarization dynamics in heavy-ion collisions. Recent studies suggest the transverse component of the vorticity field is responsible for the global spin polarization. In contrast, the longitudinal component of the vorticity field accounts for the local spin polarization. The local (longitudinal) spin polarization of $\Lambda$-hyperons arises due to the anisotropic flows in the transverse plane, indicating a quadrupole pattern of the longitudinal vorticity along the beam direction. In this study, we derive a simple solution relating the longitudinal mean spin vector with the second-order anisotropic flow coefficient due to the thermal shear tensor for an ideal uncharged fluid in a longitudinal boost invariant scenario. The present study focuses on the local spin polarization of $\Lambda$ and $\bar{\Lambda }$ in Au$+$Au and Pb$+$Pb collisions at $\sqrt{s_{NN}}$ = 200 GeV and 5.02 TeV, respectively. Further, we explore the azimuthal angle, centrality, and transverse momentum ($p_{\mathrm{T}}$) dependence study of longitudinal spin polarization using hydrodynamic and transport models. All these models predict a maximum longitudinal spin polarization in mid-central collisions around 30-50 \% centrality at $p_{\mathrm{T}}\approx$ 2.0 - 3.0 GeV/c. These findings on longitudinal spin polarization advocate the existence of a thermal medium in non-central heavy-ion collisions.

    hep-phhep-exnucl-exnucl-thPhys.Scripta(2025)·11 citations
19. 19*

    Using analytic models to describe effective PDFs

    Salvador A. Ochoa-Oregon🇲🇽 · David F. Rentería-Estrada🇪🇸 · Roger J. Hernández-Pinto🇲🇽 · German F. R. Sborlini🇪🇸 · Pia Zurita🇩🇪

    Parton distribution functions play a pivotal role in hadron collider phenomenology. They are non-perturbative quantities extracted from fits to available data, and their scale dependence is dictated by the DGLAP evolution equations. In this article, we discuss machine-assisted strategies to efficiently compute PDFs directly incorporating the scale evolution without the need of separately solving DGLAP equations. Analytical approximations to the PDFs as a function of $x$ and $Q^2$, including up to next-to-leading order effects in Quantum Chromodynamics, are obtained. The methodology is tested by reproducing the $\text{HERAPDF2.0}$ set and implementing the analytical expressions in benchmarking codes. It is found that the computational cost is reduced while the precision of the simulations stays well under control.

    hep-phhep-thPRD(2024)·2 citations
20. 20*

    Diabatic Dynamical Diquark Bound States: Mass Corrections and Widths

    Richard F. Lebed🇺🇸 · Steven R. Martinez🇺🇸

    Using the diabatic formalism, which generalizes the adiabatic approximation in the Born-Oppenheimer formalism, we apply well-known Hamiltonian methods to calculate the effect of open di-meson thresholds that lie well below the mass of elementary $c\bar{c}q{\bar{q}}^{\prime }$, $c\bar{c}s\bar{s}$, and $c\bar{c}q\bar{s}$ tetraquark bound states. We compute the resulting mass shifts for these states, as well as their decay widths to the corresponding meson pairs. Each mass eigenstate, originally produced using a bound-state approximation under the diabatic formalism, consists of an admixture of a compact diquark-antidiquark configuration (an eigenstate of the original dynamical diquark model) with an extended di-meson configuration induced by the nearest threshold. We compare our results with those from our recent work that employs a scattering formalism, and find a great deal of agreement, but also comment upon interesting discrepancies between the two approaches.

    hep-phPRD(2024)·7 citations
21. 21*

    ${\Sigma }^{+}\to p{\ell }^{+}{\ell }^{-}$ decays within the standard model and beyond

    Arnab Roy🇦🇺 · Jusak Tandean🇨🇳 · German Valencia🇦🇺

    Motivated by the LHCb measurement of the hyperon decay mode ${\Sigma }^{+}\to p{\mu }^{+}{\mu }^{-}$ and prospects for improvement, we revisit the estimates for the rate and muon forward-backward asymmetry within the standard model and beyond. The standard model prediction has a fourfold ambiguity, and we suggest ways to resolve it with other measurements, including possible studies of ${\Sigma }^{+}\to p{e}^{+}{e}^{-}$ in the BESIII and LHCb experiments. We use the recent BESIII measurements of ${\Sigma }^{+}\to p\gamma$ and ${\Sigma }^{+}\to N\pi$ to reduce the uncertainty in the long-distance contribution to ${\Sigma }^{+}\to p{\mu }^{+}{\mu }^{-}$. Beyond the standard model, we consider a general effective Hamiltonian at low energy with ten operators whose Wilson coefficients parametrize the new physics. We derive expressions for the ${\Sigma }^{+}\to p{\mu }^{+}{\mu }^{-}$ rate and the associated muon forward-backward asymmetry in terms of these coefficients. Finally, we present the constraints on these Wilson coefficients that result from both kaon and hyperon decays and emphasize their complementarity.

    hep-phhep-exPRD(2025)·14 citations
22. 22*

    Effective Field Theory for Spontaneously Broken Symmetry

    Tomas Brauner🇳🇴

    This is a preprint of an open-access book published by Springer Cham. The book gives an up-to-date overview of the physics of spontaneously broken continuous symmetry from the point of view of effective field theory. Upon building up the necessary foundations, the text reviews the classification of Nambu-Goldstone bosons and then focuses on the construction of the effective-field-theoretic description of their dynamics. Both internal and spacetime broken symmetries are covered, including numerous illustrative examples and a few selected applications, worked out in greater detail.

    ↳ hep-thcond-mat.quant-gashep-phnucl-thLect.Notes Phys.(2024)·21 citations
23. 23*

    Pion Valence Quark Distribution at Physical Pion mass of $N_f=2+1+1$ Lattice QCD

    Jack Holligan🇺🇸 · Huey-Wen Lin🇺🇸

    We present a state-of-the-art calculation of the unpolarized pion valence-quark distribution in the framework of large-momentum effective theory (LaMET) with improved handling of systematic errors as well as two-loop perturbative matching. We use lattice ensembles generated by the MILC collaboration at lattice spacing $a\approx 0.09$~fm, lattice volume $64^3\times 96$, $N_f=2+1+1$ flavors of highly-improved staggered quarks and a physical pion mass. The LaMET matrix elements are calculated with pions boosted to momentum $P_z\approx 1.72$~GeV with high-statistics of $O(10^6)$ measurements. We study the pion PDF in both hybrid-ratio and hybrid-regularization-independent momentum subtraction (hybrid-RI/MOM) schemes and also compare the systematic errors with and without the addition of leading-renormalon resummation (LRR) and renormalization-group resummation (RGR) in both the renormalization and lightcone matching. The final lightcone PDF results are presented in the modified minimal-subtraction scheme at renormalization scale $\mu =2.0$~GeV. We show that the $x$-dependent PDFs are compatible between the hybrid-ratio and hybrid-RI/MOM renormalization with the same improvements. We also show that systematics are greatly reduced by the simultaneous inclusion of RGR and LRR and that these methods are necessary if improved precision is to be reached with higher-order terms in renormalization and matching.

    ↳ hep-lathep-phJ.Phys.G(2024)·32 citations
24. 24*

    Nonlinear treatment of a black hole mimicker ringdown

    Nils Siemonsen🇺🇸

    We perform the first nonlinear and self-consistent study of the merger and ringdown of a black hole mimicking object with stable light rings. To that end, we numerically solve the full Einstein-Klein-Gordon equations governing the head-on collisions of a series of binary boson stars in the large-mass-ratio regime resulting in spinning horizonless remnants with stable light rings. We broadly confirm the appearance of features in the extracted gravitational waveforms expected based on perturbative methods: the signal from the prompt response of the remnants approaches that of a Kerr black hole in the large-compactness limit, and the subsequent emissions contain periodically appearing bursts akin to so-called gravitational wave echoes. However, these bursts occur at high frequencies and are sourced by perturbations of the remnant's internal degrees of freedom. Furthermore, the emitted waveforms also contain a large-amplitude and long-lived component comparable in frequency to black hole quasi-normal modes. We further characterize the emissions, obtain basic scaling relations of relevant timescales, and compute the energy emitted in gravitational waves.

    ↳ gr-qchep-phhep-thPRL(2024)·39 citations
25. 25*

    Bring the Heat: Tidal Heating Constraints for Black Holes and Exotic Compact Objects from the LIGO-Virgo-KAGRA Data

    Horng Sheng Chia🇺🇸 · Zihan Zhou🇺🇸 · Mikhail M. Ivanov🇺🇸

    We present the first constraints on tidal heating for the binary systems detected in the LIGO-Virgo-KAGRA (LVK) gravitational wave data. Tidal heating, also known as tidal dissipation, characterizes the viscous nature of an astrophysical body and provides a channel for exchanging energy and angular momentum with the tidal environment. Using the worldline effective field theory formalism, we introduce a physically motivated and easily interpretable parametrization of tidal heating valid for an arbitrary compact astrophysical object. We then derive the imprints of the spin-independent and linear-in-spin tidal heating effects of generic binary components on the waveform phases and amplitudes of quasi-circular orbits. Notably, the mass-weighted spin-independent tidal heating coefficient derived in this work, ${\mathcal{H}}_0$, is the dissipative analog of the tidal Love number. We constrain the tidal heating coefficients using the public LVK O1-O3 data. Our parameter estimation study includes two separate analyses: the first treats the catalog of binary events as binary black holes (BBH), while the second makes no assumption about the nature of the binary constituents and can therefore be interpreted as constraints for exotic compact objects. In the former case, we combine the posterior distributions of the individual BBH events and obtain a joint constraint of $-13<{\mathcal{H}}_0<20$ at the $90\%$ credible interval for the BBH population. This translates into a bound on the fraction of the emitted gravitational wave energy lost due to tidal heating (or gained due to radiation enhancement effects) at $|\Delta E_H/\Delta E_{\infty }|\lesssim 3\cdot 10^{-3}$. Our work provides the first robust framework for deriving and measuring tidal heating effects in merging binary systems, demonstrating its potential as a powerful probe of the nature of binary constituents and tests of new physics.

    ↳ gr-qcastro-ph.COastro-ph.HEhep-ph+1PRD(2025)·37 citations
26. 26*

    Confronting the dark matter capture rate with a continuous gravitational wave probe of local neutron stars

    Pooja Bhattacharjee🇫🇷 · Amit Dutta Banik🇮🇳

    Continuous gravitational waves (CGWs) from various astrophysical sources are one of the many future probes of upcoming gravitational wave (GW) search missions. Neutron stars (NSs) with deformity are one of the leading sources of CGW emissions. In this work, for the first time, a novel attempt to estimate the dark matter (DM) capture rate is performed using CGW as the probe to the local NS population. Competitive bounds on DM capture from the local NS population are reported when compared with DM direct search experiments and other astrophysical observations.

    ↳ astro-ph.HEastro-ph.COastro-ph.GAastro-ph.SR+1PRD(2025)·6 citations
27. 27*

    Vanilla Inflation Predicts Negative Running

    Jerome Martin🇫🇷 · Christophe Ringeval🇧🇪 · Vincent Vennin🇫🇷

    We show that the simplest, and currently favoured, theoretical realizations of cosmic inflation yield a sharp prediction for the running of the spectral index ${\alpha }_{\mathrm{S}}$. Using latest cosmological data, we compute its marginalized posterior probability distribution over the space of nearly 300 models of single-field slow-roll inflation. The most probable value is ${\alpha }_{\mathrm{S}}=-6.3\times 10^{-4}$, lying within the $98\%$ credible interval $-1.8\times 10^{-3}<{\alpha }_{\mathrm{S}}<-9.1\times 10^{-5}$. Within the landscape of all the proposed slow-roll inflationary models, positive values for the running are therefore disfavoured at more than three-sigma.

    ↳ astro-ph.COgr-qchep-phhep-thEPL(2024)·19 citations
28. 28*

    Signature of Particle Diffusion on the X-ray Spectra of the blazar Mkn 421

    C. Baheeja🇮🇳 · S. Sahayanathan🇮🇳 · F.M. Rieger🇩🇪 · C.D. Ravikumar🇮🇳

    The curvature in blazar spectrum has the potential to understand the particle dynamics in jets. We performed a detailed analysis of simultaneous Swift-XRT (0.3-10 keV) and NuSTAR (3-79 keV)} observations of Mkn 421. Our analysis of NuSTAR observations alone reveals that, during periods of low flux, the hard X-ray spectra are best represented by a steep power-law with photon index reaching $\sim$ 3. However, the spectrum exhibits significant curvature during its high flux states. To investigate this, we explore plausible diffusion processes facilitating shock acceleration in the emission region that can contribute to the observed spectral curvature. Particularly, such processes can cause gradual fall of the photon spectrum at high energies which can be represented by a sub-exponential function. The parameter that decides this spectral change can be used to characterise the energy dependence of the diffusive process. Our results suggest that the X-ray spectra of Mkn 421 are consistent with a scenario where particle acceleration is mediated through Bohm-type diffusion and the spectra beyond the synchrotron peak is modulated by the radiative loss process.

    ↳ astro-ph.HEhep-phPRD(2024)·3 citations
29. 29*

    Reduced Hubble Tension in Dark Radiation Models after DESI 2024

    Itamar J. Allali🇺🇸 · Alessio Notari🇪🇸 · Fabrizio Rompineve🇪🇸

    We investigate the presence of extra relativistic degrees of freedom in the early Universe, contributing to the effective number of neutrinos $N_{\text{eff}}$, as $\Delta N_{\text{eff}}\equiv N_{\text{eff}}-3.044\ge 0$, in light of the recent measurements of Baryon Acoustic Oscillations (BAO) by the DESI collaboration. We analyze one-parameter extensions of the $\Lambda$CDM model where dark radiation (DR) is free streaming or behaves as a perfect fluid, due to self-interactions. We report a significant relaxation of upper bounds on $\Delta N_{\text{eff}}$, with respect to previous BAO data from SDSS+6dFGS, when additionally employing Planck data (and supernovae data from Pantheon+), setting $\Delta N_{\text{eff}}\le 0.39$ ($95\%$ C.L.) for free streaming DR, and a very mild preference for fluid DR, $\Delta N_{\text{eff}}=0.221_{-0.18}^{+0.088}$ ($\le 0.46$, $95\%$ C.L.). Applying constraints from primordial element abundances leads to slightly tighter constraints on $\Delta N_{\text{eff}}$, but they are avoided if DR is produced after Big Bang Nucleosynthesis (BBN). For fluid DR we estimate the tension with the SH${}_0$ES determination of $H_0$ to be less than $3\sigma$ and as low as $2\sigma$, and for free-streaming DR the tension is below $3\sigma$ if production occurs after BBN. This lesser degree of tension motivates a combination with SH${}_0$ES in these cases, resulting in a $4.4\sigma -5\sigma$ evidence for dark radiation with $\Delta N_{\text{eff}}\simeq 0.6$ and large improvements in ${\chi }^2$ over $\Lambda$CDM, $-18\lesssim \Delta {\chi }^2\lesssim -25$. Upcoming data releases by DESI and other CMB and LSS surveys will decisively confirm or disfavour this conclusion.

    ↳ astro-ph.COhep-phJCAP(2025)·40 citations
30. 30*

    Interacting Dark Energy after DESI Baryon Acoustic Oscillation measurements

    William Giarè🇬🇧 · Miguel A. Sabogal🇧🇷 · Rafael C. Nunes🇧🇷 · Eleonora Di Valentino🇬🇧

    We investigate the implications of the Baryon Acoustic Oscillations measurement released by the Dark Energy Spectroscopic Instrument (DESI) for Interacting Dark Energy (IDE) models characterized by an energy-momentum flow from Dark Matter to Dark Energy. By combining Planck-2018 and DESI data, we observe a preference for interactions, leading to a non-vanishing interaction rate $\xi =-0.32_{-0.14}^{+0.18}$, which results in a present-day expansion rate $H_0=70.8_{-1.7}^{+1.4}$ km/s/Mpc, reducing the tension with the value provided by the SH0ES collaboration to less than $\sim 1.3\sigma$. The preference for interactions remains robust when including measurements of the expansion rate $H(z)$ obtained from the relative ages of massive, early-time, and passively-evolving galaxies, as well as when considering distance moduli measurements from Type-Ia Supernovae sourced from the Pantheon-plus catalog using the SH0ES Cepheid host distances as calibrators. Overall, the IDE framework provides an equally good, or better, explanation of both high- and low-redshift background observations compared to $\Lambda$CDM, while also yielding higher $H_0$ values that align more closely with the local distance ladder estimates. However, a limitation of the IDE model is that it predicts lower ${\Omega }_m$ and higher ${\sigma }_8$ values, which may not be fully consistent with large-scale structure data at the perturbation level.

    ↳ astro-ph.COhep-phPRL(2024)·238 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.