Fri·Jan 19, 2024Friday·January 19, 2024

1. 01*

   Lepton flavor violation by two units

   Julian Heeck🇺🇸 · Mikheil Sokhashvili🇺🇸

   Charged lepton flavor violation arises in the Standard Model Effective Field Theory at mass dimension six. The operators that induce neutrinoless muon and tauon decays are among the best constrained and are sensitive to new-physics scales up to $10^7$GeV. An entirely different class of lepton-flavor-violating operators violates lepton flavors by two units rather than one and does not lead to such clean signatures. Even the well-known case of muonium--anti-muonium conversion that falls into this category is only sensitive to two out of the three $\Delta L_{\mu }=-\Delta L_e=2$ dimension-six operators. We derive constraints on many of these operators from lepton flavor universality and show how to make further progress with future searches at Belle II and future experiments such as $Z$ factories or muon colliders.

   hep-phhep-exPLB(2024)·21 citations
2. 02*

   Sphaleron portal baryogenesis

   Chee Sheng Fong🇧🇷

   Nontrivial topological vacua of non-Abelian gauge symmetry $SU(3)\times SU(2{)}_L$ of the Standard Model play an important role in baryogenesis. In particular, the baryon (and lepton) number violation from $SU(2{)}_L$ sphaleron is a crucial ingredient for baryogenesis at weak scale or higher. In this work, we point out that generically, a baryon asymmetry is induced by an asymmetry generated in the new sector through strong $SU(3)$ and/or weak $SU(2{)}_L$ sphaleron portals and vice versa. In the standard radiation-dominated early Universe, due to phenomenological constraints, the sphaleron portal baryogenesis has to take place at cosmic temperature $T\gtrsim 10^6-10^8$ GeV together with a $(B-L)$-violating source. As an example, we show an explicit model where strong sphaleron portal baryogenesis occurs at the scale of Peccei-Quinn breaking to solve the strong CP problem and this coincides nicely with the scale where the Weinberg operator responsible for Majorana neutrino mass is in equilibrium.

   hep-ph0 citations
3. 03*

   Phase Transition to RS: Cool, not Supercool

   Rashmish K. Mishra🇺🇸 · Lisa Randall🇺🇸

   Motivated by the warped conifold compactification, we model the infrared (IR) dynamics of confining gauge theories in a Randall-Sundrum (RS)-like setup by modifying the stabilizing Goldberger-Wise (GW) potential so that it becomes large (in magnitude) in the IR and back-reacts on the geometry. We study the high-temperature phase by considering a black brane background in which we calculate the entropy and free energy of the strongly back-reacted solution. As with Buchel's result for the conifold (arXiv:2103.15188), we find a minimum temperature beyond which the black brane phase is thermodynamically unstable. In the context of a phase transition to the confining background, our results suggest that the amount of supercooling that the metastable black brane phase undergoes can be limited. It also suggests the first-order phase transition (and the associated gravitational waves from bubble collision) is not universal. Our results therefore have important phenomenological implications for early universe model building in these scenarios.

   hep-phgr-qchep-thJHEP(2024)·22 citations
4. 04*

   Elementary Particles and Plasma in the First Hour of the Early Universe

   Cheng Tao Yang🇺🇸

   This dissertation aims to deepen the understanding of the primordial composition of the Universe in the temperature range 300 MeV>T>0.02 MeV. I exploit known properties of elementary particles and apply methods of kinetic theory and statistical physics to advance the understanding of the cosmic plasma. Within the Big Bang model, we begin by considering the Universe being a highly energetic fireball, an ultra-relativistic plasma exhibiting distinct properties. Fundamental particles such as quarks, leptons, and even heavier gauge bosons play a crucial role in the understanding of the early Universe. Our research focuses on the investigation of these fundamental particles as constituents of the dense Universe plasma during the epoch which transits from primordial quark-gluon plasma to the era of normal hadron matter, passing through the decoupling of neutrinos and addressing in detail the electron-positron antimatter plasma.

   hep-phastro-ph.CO2 citations
5. 05*

   Abnormal states with unequal constituent masses

   V.A. Karmanov🇷🇺

   The Bethe-Salpeter equation for system of two oppositely charged particles not only reproduces the Coulomb spectrum, but, for enough large coupling constant $\mathcal{C}>\frac{\pi }{4}$, predicts additional levels not predicted by the Schrödinger equation. These relativistic states (called abnormal), in contrast to the normal ones, are dominated, for more than 90-99 percent, by Fock states involving the exchange particles - the photons, whereas contribution of two massive charged particles themselves is rather small (1-10 \%). Since the carrier of a large (positive) charge is a heavy ion, and the negative charge is provided by electron, the masses of two constituents are very different. It is shown that in a system with so different masses the abnormal states still exist. Moreover, the effect of unequal masses is attractive. The balance between photons and charged constituents is weakly sensitive to the mass ratio, so the photons still predominate.

   hep-phEPJC(2024)·2 citations
6. 06*

   The proton-neutron resonance states by solving Schrodinger equation

   Bao-Xi Sun🇨🇳 · Qin-Qin Cao🇨🇳 · Ying-Tai Sun🇨🇳

   The proton-neutron interaction is investigated by solving the Schrodinger equation, where a Yukawa type of potential with one pion exchanging between the proton and the neutron is assumed. Since the deutron is the unique bound state of the proton-neutron system, the coupling constant is fixed according to the binding energy of the deutron. The scattering process of the proton and the neutron is studied when the outgoing wave condition is taken into account, and two proton-neutron resonance states are obtained by solving the Schrodinger equation, which lie at $1905-i13$MeV and $2150-i342$MeV on the complex energy plane, respectively. It is no doubt that the calculation results would give some hints on the experimental research on the proton-neutron interaction in future.

   hep-phnucl-thquant-ph1 citation
7. 07*

   Toward a theory of neutrino mass and mixing

   Alexei Yu. Smirnov🇩🇪

   Among numerous theoretical ideas, approaches, mechanisms, models there are probably few elements which will eventually enter the true theory of neutrino masses and mixing. The task is to identify them. Still something conceptually important can be missed. The problems of construction of the theory are outlined. Perspectives and possible future developments are discussed.

   hep-ph1 citation
8. 08*

   The possible $K{\bar{K}}^{\ast }$ and $D{\bar{D}}^{\ast }$ bound and resonance states by solving Schrodinger equation

   Bao-Xi Sun🇨🇳 · Qin-Qin Cao🇨🇳 · Ying-Tai Sun🇨🇳

   The Schrodinger equation with a Yukawa type of potential is solved analytically. When different boundary conditions are taken into account, a series of solutions are indicated as Bessel function, the first kind of Hankel function and the second kind of Hankel function, respectively. Subsequently, the scattering processes of $K{\bar{K}}^{\ast }$ and $D{\bar{D}}^{\ast }$ are investigated. In the $K{\bar{K}}^{\ast }$ sector, the $f_1(1285)$ particle is treated as a $K{\bar{K}}^{\ast }$ bound state, therefore, the coupling constant in the $K{\bar{K}}^{\ast }$ Yukawa potential can be fixed according to the binding energy of the $f_1(1285)$ particle. Consequently, a $K{\bar{K}}^{\ast }$ resonance state is generated by solving the Schrodinger equation with the outgoing wave condition, which lie at $1417-i18$MeV on the complex energy plane. It is reasonable to assume that the $K{\bar{K}}^{\ast }$ resonance state at $1417-i18$MeV might correspond to the $f_1(1420)$ particle in the review of Particle Data Group(PDG).In the $D{\bar{D}}^{\ast }$ sector, since the $X(3872)$ particle is almost located at the $D{\bar{D}}^{\ast }$ threshold, the binding energy of it equals to zero approximately. Therefore, the coupling constant in the $D{\bar{D}}^{\ast }$ Yukawa potential is determined, which is related to the first zero point of the zero order Bessel function. Similarly to the $K{\bar{K}}^{\ast }$ case, four resonance states are produced as solutions of the Schrodinger equation with the outgoing wave condition. It is assumed that the resonance states at $3885-i1$MeV, $4029-i108$ MeV, $4328-i191$MeV and $4772-i267$MeV might be associated with the $Zc(3900)$, the $X(3940)$, the ${\chi }_{c1}(4274)$ and ${\chi }_{c1}(4685)$ particles, respectively. It is noted that all solutions are isospin degenerate.

   hep-phnucl-thquant-phCommun.Theor.Phys.(2024)·3 citations
9. 09*

   Jet Quenching: From Theory to Simulation

   Shanshan Cao🇨🇳 · Abhijit Majumder🇺🇸 · Rouzbeh Modarresi-Yazdi🇨🇦 · Ismail Soudi🇺🇸 · Yasuki Tachibana🇯🇵

   With the explosion of data on jet based observables in relativistic heavy-ion collisions at the Large Hadron Collider and the Relativistic Heavy-Ion Collider, perturbative QCD based simulations of these processes, often interacting with an expanding viscous fluid dynamical background, have taken center stage. This review is meant to bridge the gap between theory, simulation and phenomenology of jet modification in a dense medium. We will demonstrate how the existence of such end-to-end event generators with semi-realistic or even fully realistic final states allows for the most rigorous comparisons between pQCD based jet modification theory and experiment. State-of-the-art calculations of several jet based observables are presented. Extensions of this theory to jets in the small systems of $p$-$A$ and $e$-$A$ collisions is discussed.

   hep-phnucl-exnucl-thIJMPE(2024)·42 citations
10. 10*

    Semi-inclusive production of spin-3/2 hadrons in deep inelastic scattering

    Jing Zhao🇨🇳 · Zhe Zhang🇨🇳 · Zuo-tang Liang🇨🇳 · Tianbo Liu🇨🇳 · Ya-jin Zhou🇨🇳

    We investigate the production of spin-3/2 hadrons in semi-inclusive deep inelastic lepton-nucleon scatterings. The complete differential cross section is derived through the kinematic analysis and expressed in terms of 288 structure functions, corresponding to all polarization configurations and azimuthal modulations. For an unpolarized lepton beam, half of the 192 structure functions have nonzero leading order contributions in the parton model, among which 42 are from rank-3 tensor polarized fragmentation functions of the hadron. For a polarized lepton beam, one third of the 96 structure functions contribute at the leading order and 14 of them are from rank-3 tensor polarized fragmentation functions. In addition to the formalism, we perform a model estimation of the spin transfer to a $S_{hLLL}$ polarized hadron and sizable asymmetry is expected. Therefore, these newly defined observables for the production of a spin-3/2 hadron in a deep inelastic scattering process can be explored in future experiments to understand nucleon spin structures and spin-dependent fragmentation functions.

    hep-phPRD(2024)·7 citations
11. 11*

    Doubly charmed pentaquark states in QCD sum rules

    Feng-Bo Duan🇨🇳 · Qi-Nan Wang🇨🇳 · Zi-Yan Yang🇨🇳 · Xu-Liang Chen🇨🇳 · Wei Chen🇨🇳

    We have studied the mass spectra of doubly charmed pentaquark states in the ${\Lambda }_c^{(\ast )}{D}^{(\ast )}$ and ${\Sigma }_c^{(\ast )}{D}^{(\ast )}$ channels with $J^P=1/2^{\pm }$, $3/2^{\pm }$ and $5/2^{\pm }$ within the framework of QCD sum rules. We use the parity projected sum rules to separate the contributions of negative and positive parities from the two-point correlations induced by the pentaquark interpolating currents. Our results show that the bound states of $P_{cc}$ pentaquarks may exist in the ${\Lambda }_{c}D({\frac{1}{2}}^{-})$, ${\Sigma }_{c}D({\frac{1}{2}}^{-})$, ${\Sigma }_c{D}^{\ast }({\frac{3}{2}}^{-})$, ${\Lambda }_c^{\ast }D({\frac{3}{2}}^{-})$, ${\Lambda }_c^{\ast }{D}^{\ast }({\frac{5}{2}}^{-})$ channels with negative-parity and ${\Sigma }_{c}D({\frac{1}{2}}^{+})$, ${\Sigma }_c{D}^{\ast }({\frac{3}{2}}^{+})$, ${\Sigma }_c^{\ast }D({\frac{3}{2}}^{+})$ channels with positive-parity, since their masses are predicted to be lower than the corresponding meson-baryon thresholds. However, they are still allowed to decay into the ${\Xi }_{cc}^{(\ast )}\pi$ final states via strong interaction. The triply charged $P_{cc}^{+++}(ccuu\bar{d})$ and neutral $P_{cc}^0(ccdd\bar{u})$ in the isospin quartet would definitely be pentaquark states due to their exotic charges. We suggest searching for these characteristic doubly charmed pentaquark signals in the $P_{cc}^{+++}\to {\Xi }_{cc}^{(\ast )++}{\pi }^{+}/{\rho }^{+}$, ${\Sigma }_c^{(\ast )++}{D}^{(\ast )+}$ and $P_{cc}^0\to {\Xi }_{cc}^{(\ast )+}{\pi }^{-}/{\rho }^{-}$, ${\Sigma }_c^{(\ast )0}{D}^{(\ast )0}$ decays in the near future.

    hep-phhep-exhep-latPRD(2024)·21 citations
12. 12*

    Recent $B^{+}\to K^{+}\nu \bar{\nu }$ excess and muon $g-2$ illuminating light dark sector with Higgs portal

    Shu-Yu Ho🇰🇷 · Jongkuk Kim🇰🇷 · Pyungwon Ko🇰🇷

    The Belle II collaboration recently announced that they observed the $B^{+}\to K^{+}\nu \bar{\nu }$ decay process for the first time. This dineutrino mode of $B^{+}\to K^{+}\nu \bar{\nu }$ has been theoretically identified as a very clean channel. However, their result encounters a $2.7{}^{}\sigma$ deviation from the Standard Model (SM) calculation. On the other hand, last year, Fermilab released new data on muon $g-2$ away from the SM expectation with $5{}^{}\sigma$. In this letter, we study the simplest UV-complete $\text{U}(1{)}_{{\text{L}}_{\mu }-{\text{L}}_{\tau }}^{}$-charged complex scalar Dark Matter (DM) model. Thanks to the existence of light dark Higgs boson and light dark photon, we can explain the observed relic density of DM and resolve the results reported by both Belle II and Fermilab experiments simultaneously. As a byproduct, the Hubble tension is alleviated by taking $\Delta N_{\text{eff}}^{}\simeq 0.3$ induced by the light dark photon.

    hep-phhep-exPRD(2025)·50 citations
13. 13*

    A potential approach to the $X(3872)$ thermal behavior

    Néstor Armesto🇪🇸 · Miguel Ángel Escobedo🇪🇸 · Elena G. Ferreiro🇪🇸 · Víctor López-Pardo🇪🇸

    We study the potential of $X(3872)$ at finite temperature in the Born-Oppenheimer approximation under the assumption that it is a tetraquark. We argue that, at large number of colors, it is a good approximation to assume that the potential consists in a real part plus a constant imaginary term. The real part is then computed adapting an approach by Rothkopf and Lafferty and using as input lattice QCD determinations of the potential for hybrids. This model allows us to qualitatively estimate at which temperature range the formation of a heavy tetraquark is possible, and to propose a qualitative picture for the dissociation of the state in a medium. Our approach can be applied to other suggested internal structures for the $X(3872)$ and to other exotic states.

    hep-phnucl-thPLB(2024)·11 citations
14. 14*

    Heavy Quarks in Polarised Deep-Inelastic Scattering at the Electron-Ion Collider

    Felix Hekhorn🇮🇹 · Giacomo Magni🇳🇱 · Emanuele R. Nocera🇮🇹 · Tanjona R. Rabemananjara🇳🇱 · Juan Rojo🇳🇱 · Adrianne Schaus🇳🇱 · Roy Stegeman🇬🇧

    We extend the FONLL general-mass variable-flavour-number scheme to the case of longitudinally polarised DIS structure functions, accounting for perturbative corrections up to $\mathcal{O}({\alpha }_s^2)$. We quantify the impact of charm quark mass and higher-order perturbative corrections on projected measurements of inclusive and charm-tagged longitudinal asymmetries at the Electron-Ion Collider (EIC) and at the Electron-ion collider in China (EicC). We demonstrate how the inclusion of these corrections is essential to compute predictions with an accuracy that matches the projected precision of the measurements. The computation is made publicly available through the open-source EKO and YADISM programs

    hep-phhep-exnucl-exnucl-thEPJC(2024)·19 citations
15. 15*

    Determination of quark and lepton masses and mixings in the microscopic model

    Bodo Lampe🇩🇪

    Recently, formulas for the mixing matrices of quarks and leptons have been put forward. My contribution here describes the relevant foundational and technical aspects which have led to those results. The work has been carried out in the framework of the microscopic model. The most general ansatz for the interactions among tetrons leads to a Hamiltonian H involving Dzyaloshinskii-Moriya (DM), Heisenberg and torsional isospin forces. Diagonalization of the Hamiltonian provides for 24 eigenvalues which are identified as the quark and lepton masses. While the masses of the third and second family arise from DM and Heisenberg type of isospin interactions, light family masses are related to torsional interactions among tetrons. Neutrino masses turn out to be special in that they are given in terms of tiny isospin non-conserving DM, Heisenberg and torsional couplings. The approach not only leads to masses, but also allows to calculate the quark and lepton eigenstates, an issue, which is important for the determination of the CKM and PMNS mixing matrices. The almost exact isospin conservation of the system dictates the form of the lepton states and makes them independent of all the couplings in H. Much in contrast, there is a strong dependence of the quark states on the coupling strengths, and a promising hierarchy between the quark family mixings shows up.

    hep-phhep-exPoS(2024)·1 citation
16. 16*

    Determination of the theory uncertainties from missing higher orders on NNLO parton distributions with percent accuracy

    The NNPDF Collaboration: Richard D. Ball🇬🇧 · Andrea Barontini🇮🇹 · Alessandro Candido🇮🇹 · Stefano Carrazza🇮🇹 · Juan Cruz-Martinez🇨🇭 · Luigi Del Debbio🇬🇧 · Stefano Forte🇮🇹 · Tommaso Giani🇳🇱 · Felix Hekhorn🇮🇹 · Zahari Kassabov🇬🇧 · Niccolò Laurenti🇮🇹 · Giacomo Magni🇳🇱 and 6 other authors

    We include uncertainties due to missing higher order corrections to QCD computations (MHOU) used in the determination of parton distributions (PDFs) in the recent NNPDF4.0 set of PDFs. We use our previously published methodology, based on the treatment of MHOUs and their full correlations through a theory covariance matrix determined by scale variation, now fully incorporated in the new NNPDF theory pipeline. We assess the impact of the inclusion of MHOUs on the NNPDF4.0 central values and uncertainties, and specifically show that they lead to improved consistency of the PDF determination with an ensuing moderate reduction of PDF uncertainties at NNLO.

    hep-phEPJC(2024)·77 citations
17. 17*

    Energy-momentum tensor of the dilute (3+1)D Glasma

    Andreas Ipp🇦🇹 · Markus Leuthner🇦🇹 · David I. Müller🇦🇹 · Sören Schlichting🇩🇪 · Kayran Schmidt🇦🇹 · Pragya Singh🇫🇮

    We present a succinct formulation of the energy-momentum tensor of the Glasma characterizing the initial color fields in relativistic heavy-ion collisions in the Color Glass Condensate effective theory. We derive concise expressions for the (3+1)D dynamical evolution of symmetric nuclear collisions in the weak field approximation employing a generalized McLerran-Venugopalan model with non-trivial longitudinal correlations. Utilizing Monte Carlo integration, we calculate in unprecedented detail non-trivial rapidity profiles of early-time observables at RHIC and LHC energies, including transverse energy densities and eccentricities. For our setup with broken boost invariance, we carefully discuss the placement of the origin of the Milne frame and interpret the components of the energy-momentum tensor. We find longitudinal flow that deviates from standard Bjorken flow in the (3+1)D case and provide a geometric interpretation of this effect. Furthermore, we observe a universal shape in the flanks of the rapidity profiles regardless of collision energy and predict that limiting fragmentation should also hold at LHC energies.

    hep-phnucl-thPRD(2024)·19 citations
18. 18*

    A rotation-equivariant graph neural network for learning hadronic SMEFT effects

    Suman Chatterjee🇦🇹 · Sergio Sánchez Cruz🇨🇭 · Robert Schöfbeck🇦🇹 · Dennis Schwarz🇦🇹

    We introduce a graph neural network architecture designed to extract novel phenomena in the Standard Model Effective Field Theory (SMEFT) context from LHC collision data. The proposed infrared- and collinear-safe architecture is sensitive to the angular orientation of radiation patterns in jets from hadronic decays of highly energetic massive particles. Equivariance with respect to rotations around the jet axis allows for extracting the information on the angular orientation decoupled from the jet substructure. We demonstrate the robustness of the approach and its potential for future probes of the SMEFT at the LHC through toy studies and with realistic event simulations of the WZ process in the semileptonic decay channel.

    hep-phhep-exPRD(2024)·11 citations
19. 19*

    The Smallness of Matter Effects in Long-Baseline Muon Neutrino Disappearance

    Peter B. Denton🇺🇸 · Stephen J. Parke🇺🇸

    Current long-baseline accelerator experiments, NOvA and T2K, are making excellent measurements of neutrino oscillations and the next generation of experiments, DUNE and HK, will make measurements at the $\mathcal{O}(1\%)$ level of precision. These measurements are a combination of the appearance channel which is more challenging experimentally but depends on many oscillation parameters, and the disappearance channel which is somewhat easier and allows for precision measurements of the atmospheric mass splitting and the atmospheric mixing angle. It is widely recognized that the matter effect plays a key role in the appearance probability, yet the effect on the disappearance probability is surprisingly small for these experiments. Here we investigate both exactly how small the effect is and show that it just begins to become relevant in the high statistics regime of DUNE.

    hep-phhep-exPRD(2024)·9 citations
20. 20*

    Weighing Milky Way and Andromeda in an expanding $\Lambda$CDM Universe: Decreasing the Local Group mass

    David Benisty🇩🇪

    The dynamics of the Local Group (LG), especially the contribution of the Milky Way (MW) and Andromeda (M31) galaxies, is sensitive to the presence of dark energy. This work analyzes the evolution of the LG by considering it as a two-body problem in a homogeneous and isotropic expanding spacetime in a full $\Lambda$ cold dark matter $(\Lambda$CDM) background. Using the timing argument (TA), which links LG dynamics to LG mass, we find that the complete $\Lambda$CDM background predicts a $\sim 10\%$ lower mass for the LG; while $\Lambda$ alone predicts a $\sim 10\%$ higher mass. The TA mass is modified by (i) simulations and (ii) the effect of the Large Magellanic Cloud (LMC) to alleviate the poorly constrained internal mass distributions of M31 and the MW, their time evolution, and the unknown distribution of dark matter between them. First, using IllustrisTNG simulations, we accounted for the effects of two extended halos and their environment (rather than point particles) and predicted their mass $\left(3.89\pm 0.62\right)\cdot 10^{12}{M}_{\odot }$. Second, the LMC effectively changes the separation and velocities of M31 toward the MW and reduces the predicted mass to $\left(2.33\pm 0.72\right)\cdot 10^{12}{M}_{\odot }$. Despite the uncertainties around dark matter between these galaxies, the overall estimated mass is compatible with the mere sum of the MW and M31 masses. The total mass of the TA is compatible with other estimates, such as the Hubble flow and the Virial Theorem with other dwarf galaxies. The combined result shows, for the first time, that a lower mass estimate can be obtained from the TA, with a consistent embedding and other systematic effects, and without an additional dark matter halo around the galaxies.

    ↳ astro-ph.COastro-ph.GAastro-ph.SRgr-qc+1Astron.Astrophys.(2024)·16 citations
21. 21*

    Hadronisation in event generators from small to large systems

    Yuuka Kanakubo🇫🇮 · Yasuki Tachibana🇯🇵 · Tetsufumi Hirano🇯🇵

    The results of the dynamical core-corona initialisation framework in p+p and Pb+Pb collisions at the LHC energies are presented. We extract the fractions of final hadron yields originating from equilibrated and non-equilibrated matter as functions of multiplicity. We show that the contribution from non-equilibrated matter is non-negligible even in intermediate and central Pb+Pb collisions. The particle production from non-equilibrated matter behaves as a correction on $c_2\{4\}$ that is purely obtained from the equilibrated matter. The result poses a warning on Bayesian parameter estimation with conventional hydrodynamic models. The observed flow coefficients might need a reinterpretation with new dynamical models which incorporate the particle production from non-equilibrated matter.

    ↳ nucl-thhep-phnucl-exPoS(2024)·0 citations
22. 22*

    Quantum Gravity Effective Action Provides Entropy of The Universe

    Ken-ji Hamada🇯🇵

    The effective action in renormalizable quantum theory of gravity provides entropy because the total Hamiltonian vanishes. Since it is a renormalization group invariant that is constant in the process of cosmic evolution, we can show conservation of entropy, which is an ansatz in the standard cosmology. Here, we study renormalizable quantum gravity that exhibits conformal dominance at high energy beyond the Planck scale. The current entropy of the universe is derived by calculating the effective action under the scenario of quantum gravity inflation caused by its dynamics. We then argue that ghost modes must be unphysical but are necessary for the Hamiltonian to vanish and for entropy to exist in gravitational systems.

    ↳ hep-thastro-ph.COgr-qchep-phParticles(2024)·2 citations
23. 23*

    New classification method for Equivalence Classes on $S^1/Z_2$ and $T^2/Z_3$ Orbifolds

    Kota Takeuchi🇯🇵 · Tomohiro Inagaki🇯🇵

    In five- and six-dimensional $U(N)$ and $SU(N)$ gauge theories compactified on $S^1/Z_2$ and $T^2/Z_3$ orbifolds, we propose a new method to classify the equivalence classes (ECs) of boundary conditions (BCs) wihtout depending on the structure of gauge transformations. Some of the BCs are connected through gauge transformations and constitute ECs, each of which contains physically equivalent BCs. Previous methods for classifying ECs have been used specific gauge transformations. In this paper, we show that a geometric property of orbifolds significantly narrows down the possibilities of connecting BCs and completes the classification of ECs.

    ↳ hep-thhep-phPTEP(2024)·4 citations
24. 24*

    Algorithm for differential equations for Feynman integrals in general dimensions

    Leonardo de la Cruz🇫🇷 · Pierre Vanhove🇫🇷

    We present an algorithm for determining the minimal order differential equations associated to a given Feynman integral in dimensional or analytic regularisation. The algorithm is an extension of the Griffiths-Dwork pole reduction adapted to the case of twisted differential forms. In dimensional regularisation, we demonstrate the applicability of this algorithm by explicitly providing the inhomogeneous differential equations for the multiloop two-point sunset integrals: up to 20 loops for the equal mass case, the generic mass case at two- and three-loop orders. Additionally, we derive the differential operators for various infrared-divergent two-loop graphs. In the analytic regularisation case, we apply our algorithm for deriving a system of partial differential equations for regulated Witten diagrams, which arise in the evaluation of cosmological correlators of conformally coupled ${\varphi }^4$ theory in four-dimensional de Sitter space.

    ↳ hep-thhep-phmath-phmath.MPLett.Math.Phys.(2024)·33 citations
25. 25*

    Dense Hadronic Matter in Neutron Stars

    Laura Tolos🇪🇸

    In this lecture we discuss the properties of dense hadronic matter inside neutron stars. In particular, we pay attention to the role of strangeness in the core of neutron stars, by analysing the presence of baryons and mesons with strangeness. We consider two interesting possible scenarios in their interior, that is, the existence of hyperons leading to the so-called hyperon puzzle and the presence of a kaon condensed phase inside neutron stars.

    ↳ nucl-thastro-ph.HEhep-phActa Phys.Polon.B(2024)·4 citations
26. 26*

    Some simple theories of gravity with propagating nonmetricity

    Yusuke Mikura🇯🇵 · Roberto Percacci🇮🇹

    We investigate symmetric Metric-Affine Theories of Gravity with a Lagrangian containing all operators of dimension up to four that are relevant to free propagation in flat space. Complementing recent work in the antisymmetric case, we derive the conditions for the existence of a single massive particle with good properties, in addition to the graviton.

    ↳ gr-qcastro-ph.COhep-phhep-thEPJC(2025)·25 citations
27. 27*

    Antiproton Bounds on Dark Matter Annihilation from a Combined Analysis Using the DRAGON2 Code

    Pedro De la Torre Luque🇸🇪 · Martin Wolfgang Winkler🇺🇸 · Tim Linden🇸🇪

    Early studies of the AMS-02 antiproton ratio identified a possible excess over the expected astrophysical background that could be fit by the annihilation of a weakly interacting massive particle (WIMP). However, recent efforts have shown that uncertainties in cosmic-ray propagation, the antiproton production cross-section, and correlated systematic uncertainties in the AMS-02 data, may combine to decrease or eliminate the significance of this feature. We produce an advanced analysis using the DRAGON2 code which, for the first time, simultaneously fits the antiproton ratio along with multiple secondary cosmic-ray flux measurements to constrain astrophysical and nuclear uncertainties. Compared to previous work, our analysis benefits from a combination of: (1) recently released AMS-02 antiproton data, (2) updated nuclear fragmentation cross-section fits, (3) a rigorous Bayesian parameter space scan that constrains cosmic-ray propagation parameters. We find no statistically significant preference for a dark matter signal and set strong constraints on WIMP annihilation to $b\bar{b}$, ruling out annihilation at the thermal cross-section for dark matter masses below $\sim 200$~GeV. We do find a positive residual that is consistent with previous work, and can be explained by a $\sim 70$~GeV WIMP annihilating below the thermal cross-section. However, our default analysis finds this excess to have a local significance of only 2.8$\sigma$, which is decreased to 1.8$\sigma$ when the look-elsewhere effect is taken into account.

    ↳ astro-ph.HEhep-phJCAP(2024)·22 citations
28. 28*

    Entanglement Entropy in Scalar Quantum Electrodynamics

    Samuel Fedida🇬🇧 · Anupam Mazumdar🇳🇱 · Sougato Bose🇬🇧 · Alessio Serafini🇬🇧

    We find the entanglement entropy of a subregion of the vacuum state in scalar quantum electrodynamics, working perturbatively to the 2-loops level. Doing so leads us to derive the Maxwell-Proca propagator in conical Euclidean space. The area law of entanglement entropy is recovered in both the massive and massless limits of the theory, as is expected. These results yield the renormalisation group flow of entanglement entropy, and we find that loop contributions suppress entanglement entropy. We highlight these results in the light of the renormalization group flow of couplings and correlators, which are increased in scalar quantum electrodynamics, so that the potential tension between the increase in correlations between two points of spacetime and the decrease in entanglement entropy between two regions of spacetime with energy is discussed. We indeed show that the vacuum of a subregion of spacetime purifies with energy in scalar quantum electrodynamics, which is related to the concept of screening.

    ↳ hep-thhep-phquant-phPRD(2024)·15 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.