Tue·May 30, 2023Tuesday·May 30, 2023

1. 01*

   Interaction field strength between a scalar particle and two massless vector bosons in presence of an external magnetic field

   Jorge Jaber-Urquiza🇲🇽 · Angel Sanchez🇲🇽

   In this work we study the interaction strength among a neutral scalar boson and two massless vector bosons in presence of an external magnetic field. Based on global symmetries, we build the general tensor structure amplitude ${\mathcal{M}}^{\mu \nu }$, for the process $V^{\mu }+V^{\nu }⟶\varphi$, in terms of the vector bosons polarization states. Then, we present a novel methodology to compute the one-loop amplitude contributions for an homogeneous magnetic field with arbitrary strength. With the obtained results, expressed in terms of integrals over Schwinger parameters, we explore its behavior in two regions, widely used in the literature, the strong and weak field strength regions. The methodology presented in this work can be employed to compute an arbitrary process in presence of an external magnetic field where the initial and final states are neutral.

   hep-phhep-thPRD(2023)·4 citations
2. 02*

   Vector meson effects on the multi-skyrmion states from the rational map ansatz

   Jun-Shuai Wang🇨🇳 · Yong-Liang Ma🇨🇳

   The roles of the lightest vector mesons $\rho$ and $\omega$ in the multi-skyrmion states are studied using the hidden local symmetry approach upto the next to leading order including the homogeneous Wess-Zumino terms. The low energy constants in the effective field theory are determined by using the Sakai-Sugimoto model and the flat-space five-dimensional Yang-Mills action. With only two inputs, $m_{\rho }$, and $f_{\pi }$, all the low energy constants can be determined without ambiguity. The vector meson effects can be investigated by integrating them in order and the influence from the geometry can be clarified by comparing the results using the low energy constants estimated from the Sakai-Sugimoto model and the flat-space five-dimensional Yang-Mills action. We find that the $\rho$ meson reduces the masses of the multi-skyrmion states and increases the overlaps of the constituents of the multi-skyrmion states while the $\omega$ meson repulses the constituents of the multi-skyrmion states and increases their masses, therefore these vector mesons are important in Skyrme model approach to nuclei. we also find that the warping factor which is an essential element in the holographic model of QCD affects the properties of the multi-skyrmion states and cannot be ignored.

   hep-phhep-thnucl-thSCPMA(2023)·1 citation
3. 03*

   Flavor Violating Di- Higgs Coupling

   Fayez Abu-Ajamieh🇮🇳 · Marco Frasca🇮🇹 · Sudhir K. Vempati🇮🇳

   Di-Higgs couplings to fermions of the form $h^2\overline{f}f$ are absent in the Standard Model, however, they are present in several physics Beyond Standard Model (BSM) extensions, including those with vector-like fermions. In Effective Field Theories (EFTs), such as the Standard Model Effective Field Theory (SMEFT) and the Higgs Effective Field Theory (HEFT), these couplings appear at dimension 6 and can in general, be flavour-violating (FV). In the present work, we employ a bottom-up approach to investigate the FV in the lepton and quarks sectors through the di-Higgs effective couplings. We assume that all FV arises from this type of couplings and assume that the Yukawa couplings $Y_{ij}$ are given by their SM values, i.e. $Y_{ij}=\sqrt{2}{m}_i{\delta }_{ij}/v$. In the lepton sector, we set upper limits on the Wilson coefficients $C_{l{l}^{\prime }}$ from $l\to 3l^{\prime }$ decays, $l\to l\gamma$ decays, muonium oscillations, the $(g-2{)}_{\mu }$ anomaly, LEP searches, muon conversion in nuclei, FV Higgs decays, and $Z$ decays. We also make projections on some of these coefficients from Belle II, the Mu2e experiment and the LHC's High Luminosity (HL) run. In the quark sector, we set upper limits on the Wilson coefficients $C_{q{q}^{\prime }}$ from meson oscillations and from $B$-physics searches. A key takeaway from this study is that current and future experiments should set out to measure the effective di-Higgs couplings $C_{f{f}^{\prime }}$, whether these couplings are FV or flavour-conserving. We also present a matching between our formalism and the SMEFT operators and show the bounds in both bases.

   hep-ph8 citations
4. 04*

   Multiparton Cwebs at five loops

   Shubham Mishra🇮🇳 · Sourav Pal🇮🇳 · Aditya Srivastav🇮🇳 · Anurag Tripathi🇮🇳

   Scattering amplitudes involving multiple partons are plagued with infrared singularities. The soft singularities of the amplitude are captured by the soft function which is defined as the vacuum expectation value of Wilson line correlators. Renormalization properties of soft function allows us to write it as an exponential of the finite soft anomalous dimension. An efficient way to study the soft function is through a set of Feynman diagrams known as Cwebs (webs). We present the mixing matrices and exponentiated colour factors (ECFs) for the Cwebs at five loops that connect six Wilson lines, except those that are related by relabeling of Wilson lines. Further, we express these ECFs in terms of 29 basis colour factors. We also find that this basis can be categorized into two colour structures. Our results are the first key ingredients for the calculation of the soft anomalous dimension at five loops.

   hep-phhep-thJHEP(2024)·9 citations
5. 05*

   Electroweak symmetry breaking by gravity

   Yuri Shtanov🇺🇦

   We consider a simple scale-invariant action coupling the Higgs field to the metric scalar curvature $R$ and containing an $R^2$ term that exhibits spontaneous breaking of scale invariance and electroweak symmetry. The coefficient of the $R^2$ term in this case determines the self-coupling of the Higgs boson in the Einstein frame, and the scalaron becomes a dilaton weakly coupled to the Higgs boson. Majorana mass terms for right-handed neutrinos can be generated in a scale-invariant manner by using the Higgs-field invariant; in this case, the existing experimental limits on the Higgs-boson total width rule out Majorana mass values in a certain range. The model inherits the naturalness issues of general relativity connected with the smallness of the gravitational and cosmological constants.

   hep-phgr-qchep-thJHEP(2024)·7 citations
6. 06*

   Semi-inclusive decays of $B$ meson into a dark anti-baryon and baryons

   Yu-Ji Shi🇨🇳 · Ye Xing🇨🇳 · Zhi-Peng Xing🇨🇳

   Using the recently developed $B$-Mesogenesis scenario, we studied the semi-inclusive decays of $B$ meson into a dark anti-baryon $\psi$ plus any possible states $X$ containing $u/c$ and $d/s$ quarks with unit baryon number. The two types of effective Lagrangians proposed by the scenario are both considered in the study. The semi-inclusive decay branching fractions of $B\to X\psi$ are calculated by the method of heavy quark expansion, where the non-perturbative contributions from the matrix elements of dimension-5 operators are included. We obtained the branching fractions as functions of the dark anti-baryon mass. Using the experimental upper limits of the branching fractions, we presented the constraints of the coupling constants in the $B$-Mesogenesis scenario.

   hep-phhep-exEPJC(2023)·15 citations
7. 07*

   Status of G2HDM with right handed neutrino coupling in the light of $b\to c\tau \nu$ anomalies

   Nilakshi Das🇮🇳 · Amit Adhikary🇵🇱 · Rupak Dutta🇮🇳

   Recent experimental measurements of several observables in semileptonic B meson decays have pointed towards the possibility of new physics. The LHCb collaboration has reported a significant deviation, exceeding $3.2\sigma$, in the combined measurement of the ratio of branching ratios $R(D)-R(D^{\star })$ from the predictions of the standard model. Furthermore, other observables, such as $R_{J/\psi }$, $P_{\tau }^{D^{\star }}$, $F_L^{D^{\star }}$, and $R_{{\Lambda }_c}$ in the $b\to c\ell \nu$ transition, have also exhibited noticeable deviations from the standard model predictions. Motivated by these anomalies in the $b\to c\tau \nu$ transitions, we perform a log-likelihood fit incorporating new physics coming from right-handed neutrino couplings and explored the implications of a charged Higgs boson within a generic two Higgs doublet model (G2HDM). Our comprehensive analysis, focused on the $\tau \nu$ and $b\tau \nu$ final states, was performed using the High Luminosity run of the Large Hadron Collider (HL-LHC). We demonstrate that HL-LHC has the sensitivity to exclude the remaining allowed region in G2HDM model in explaining these anomalies with charged Higgs boson coupled to right-handed neutrino.

   hep-phhep-exInt.J.Mod.Phys.A(2026)·10 citations
8. 08*

   Solar neutrinos with CE$\nu$NS and flavor-dependent radiative corrections

   Nityasa Mishra🇺🇸 · Louis E. Strigari🇺🇸

   We examine solar neutrinos in dark matter detectors including the effects of flavor-dependent radiative corrections to the CE$\nu$NS cross section. Working within a full three-flavor framework, and including matter effects within the Sun and Earth, detectors with thresholds $\lesssim 1$ keV and exposures of $\sim 100$ ton-year could identify contributions to the cross section beyond tree level. The differences between the cross sections for the flavors, combined with the difference in fluxes, would provide a new and unique method to study the muon and tau components of the solar neutrino flux. Flavor-dependent corrections induce a small day-night asymmetry of $<|3\times 10^{-4}|$ in the event rate, which if ultimately accessible would provide a novel probe of flavor oscillations.

   hep-phastro-ph.HEastro-ph.SRPRD(2023)·20 citations
9. 09*

   Bottomonium suppression at RHIC and LHC in an open quantum system approach

   Michael Strickland🇺🇸 · Sabin Thapa🇺🇸

   We present potential non-relativistic quantum chromodynamics (pNRQCD) predictions for bottomonium suppression in sqrt(sNN) = 200 GeV, 2.76 TeV, and 5.02 TeV heavy-ion collisions using an open quantum systems (OQS) description of the reduced heavy-quark anti-quark density matrix. Compared to prior OQS+pNRQCD studies we include the rapidity dependence of bottomonium production and evolution, allowing for a fully 3-dimensional description of bottomonium trajectories in the quark-gluon plasma. The underlying formalism used to compute the ground and excited state survival probabilities is based on a Lindblad equation that is accurate to next-to-leading order (NLO) in the binding energy over temperature. For the background evolution, we make use of a 3+1D viscous hydrodynamics code which reproduces soft hadron observables at all three collision energies. We find good agreement between NLO OQS+pNRQCD predictions and data taken at LHC energies, however, at RHIC energies, there is tension with recent bottomonium suppression measurements by the STAR collaboration.

   hep-phnucl-thPRD(2023)·8 citations
10. 10*

    Phenomenological implications of nonlocal quantum electrodynamics

    Antonio Capolupo🇮🇹 · Aniello Quaranta🇮🇹 · Raoul Serao🇮🇹

    We analyze several phenomenological implications of a nonlocal generalization of quantum electrodynamics (QED). We compute the nonlocal corrections to the photon propagator up to one loop, and we show that nonlocality leads to a change of the Coulomb potential. We then investigate the ensuing modifications to the Lamb shift and to the electrostatic forces and comparing our results with the data from the muonic hydrogen anomaly, we set lower bounds on the nonlocality scales. We also discuss the running of the electromagnetic coupling for the nonlocal theory. The results obtained indicate that future experimental analyses on atomic phenomena, such as the Lamb shift, could allow to verify the presence of non-local effects on microscopic scales and impose effective limits on the non-locality scale.

    hep-phphysics.atom-ph3 citations
11. 11*

    Thermal Leptogenesis in the Minimal Gauged $U(1{)}_{L_{\mu }-L_{\tau }}$ Model

    Alessandro Granelli🇮🇹 · Koichi Hamaguchi🇯🇵 · Natsumi Nagata🇯🇵 · Maura E. Ramirez-Quezada🇯🇵 · Juntaro Wada🇯🇵

    We discuss the thermal leptogenesis mechanism within the minimal gauged U(1)${}_{L_{\mu }-L_{\tau }}$ model to explain the observed baryon asymmetry of the Universe (BAU). In such framework, the phases of the Pontecorvo-Maki-Nakagawa-Sakata neutrino mixing matrix and the sum of the Standard Model neutrino masses are predictable because of a restricted neutrino mass matrix structure. Additionally, in the context of thermal leptogenesis, the BAU can be computed in terms of the three remaining free variables that parameterise the right-handed neutrino masses and their Yukawa couplings to the Higgs and lepton doublets. We identify the ranges of such parameters for which the correct BAU can be reproduced. We adopt the formalism of the density matrix equations to fully account for flavour effects and consider the decays of all the three right-handed neutrinos. Our analysis reveals that thermal leptogenesis is feasible within a wide parameter space, specifically for Yukawa couplings ranging from approximate unity to $\mathcal{O}(0.03-0.05)$ and mass of the lightest right-handed neutrino $M_1\gtrsim 10^{11-12}\text{GeV}$, setting a leptogenesis scale in the considered model which is higher than that of the non-thermal scenario.

    hep-phJHEP(2023)·12 citations
12. 12*

    Tamed loops: A way to obtain finite loop results without UV divergences

    Lian-Bao Jia🇨🇳

    For loops with UV divergences, assuming that the physical contributions of loops from UV regions are insignificant, a method of UV-free scheme described by an equation is introduced to derive loop results without UV divergences in calculations, i.e., a route of the analytic continuation ${\mathcal{T}}_{\mathrm{F}}\to {\mathcal{T}}_{\mathrm{P}}$ besides the traditional route $\infty -\infty$ in mathematical structure. This scheme provides a new perspective to an open question of the hierarchy problem of Higgs mass, i.e., an alternative interpretation without fine-tuning within the standard model.

    hep-phCommun.Theor.Phys.(2026)·2 citations
13. 13*

    Extraction of Kaon Partonic Distribution Functions from Drell-Yan and $J/\psi$ Production Data

    Claude Bourrely🇫🇷 · Franco Buccella🇮🇹 · Wen-Chen Chang🇹🇼 · Jen-Chieh Peng🇺🇸

    We present an analysis to extract kaon parton distribution functions (PDFs) for the first time using meson-induced Drell-Yan and quarkonium production data. Starting from the statistical model first developed for determining the partonic structure of spin-1/2 nucleon and later applied to the spin-0 pion, we have extended this approach to perform a global fit to existing kaon-induced Drell-Yan and $J/\psi$ production data. These data are well described by the statistical model, allowing a first extraction of the kaon PDFs. We find that both the Drell-Yan and the $J/\psi$ data favor a harder valence distribution for strange quark than for up quark in kaon. The kaon gluon distribution is further constrained by the $J/\psi$ production data. In particular, the momentum fraction carried by gluons is found to be similar for pion and kaon.

    hep-phPLB(2024)·16 citations
14. 14*

    Vacuum Stability as a Guide for Model Building

    Gudrun Hiller🇩🇪 · Tim Höhne🇩🇪 · Daniel F. Litim🇬🇧 · Tom Steudtner🇩🇪

    We explain why vector-like fermions are natural candidates to lift the Standard Model vacuum instability. Results are further discussed from the viewpoint of criticality. Several models allow for vector-like quarks and leptons in the TeV-range which can be searched for at the LHC.

    hep-phhep-th9 citations
15. 15*

    Ultraviolet Sensitivity of Peccei-Quinn Inflation

    Davide Dal Cin🇮🇹 · Takeshi Kobayashi🇮🇹

    The radial direction of the Peccei--Quinn field can drive cosmic inflation, given a non-minimal coupling to gravity. This scenario has been considered to simultaneously explain inflation, the strong $CP$ problem, and dark matter. We argue that Peccei--Quinn inflation is extremely sensitive to higher-dimensional operators. Further combining with the discussion on the axion quality required for solving the strong $CP$ problem, we examine the validity of this scenario. We also show that after Peccei--Quinn inflation, resonant amplifications of the field fluctuation is inevitably triggered.

    hep-phastro-ph.COhep-thPRD(2023)·7 citations
16. 16*

    Accretion onto a static spherically symmetric regular MOG dark compact object

    Kourosh Nozari🇮🇷 · Sara Saghafi🇮🇷 · Fateme Aliyan🇮🇷

    In astrophysics, the process of a massive body acquiring matter is referred to as accretion. The extraction of gravitational energy occurs as a result of the infall. Since it converts gravitational energy into radiation, accretion onto dark compact objects, e.g. black holes, neutron stars, and white dwarfs is an extremely significant process in the astrophysical context. Accretion process is a fruitful way to explore the features of modified gravity (MOG) theories by testing the behavior of their solutions associated with dark compact objects. In this paper, we study the motion of electrically neutral and charged particles moving in around a regular spherically symmetric MOG dark compact object to explore their related innermost stable circular orbit (ISCO) and energy flux. Then, we turn to investigate the accretion of perfect fluid onto the regular spherically symmetric MOG dark compact object. We obtain analytical expressions for four-velocity and proper energy density of the accreting fluid. We see that the MOG parameter increases the ISCO radius of either electrically neutral or charged test particles while it decreases the corresponding energy flux. Moreover, the energy density and the radial component of the four-velocity of the infalling fluid decrease by increasing the MOG parameter near the central source.

    ↳ gr-qcastro-ph.HEhep-phhep-thEPJC(2023)·14 citations
17. 17*

    Asymptotically locally flat and AdS higher-dimensional black holes of Einstein-Horndeski-Maxwell gravity in the light of EHT observations: shadow behavior and deflection angle

    Kourosh Nozari🇮🇷 · Sara Saghafi🇮🇷

    Unification of gravity with other interactions, achieving the ultimate framework of quantum gravity, and fundamental problems in particle physics and cosmology motivate to consider extra spatial dimensions. The impact of these extra dimensions on the modified theories of gravity has attracted a lot of attention. One way to examine how extra dimensions affect the modified gravitational theories is to analytically investigate astrophysical phenomena, such as black hole shadows. In this study, we aim to investigate the behavior of the shadow shapes of higher-dimensional charged black hole solutions including asymptotically locally flat (ALF) and asymptotically locally AdS (ALAdS) in Einstein-Horndeski-Maxwell (EHM) gravitational theory. We utilize the Hamilton-Jacobi method to find photon orbits around these black holes as well as the Carter approach to formulate the geodesic equations. We examine how extra dimensions, negative cosmological constant, electric charge, and coupling constants of the EHM gravity affect the shadow size of the black hole. Then, we constrain these parameters by comparing the shadow radius of these black holes with the shadow size of M87* supermassive black hole captured by the Event Horizon Telescope (EHT) collaborations. We discover that generally the presence of extra dimensions within the EHM gravity results in reducing the shadow size of higher-dimensional ALF and ALAdS charged black holes, whereas the impact of electric charge on the shadow of these black holes is suppressible....

    ↳ gr-qcastro-ph.HEhep-phhep-thEPJC(2023)·43 citations
18. 18*

    QCD-based charge symmetry breaking interaction and the Okamoto-Nolen-Schiffer anomaly

    Hiroyuki Sagawa🇯🇵 · Tomoya Naito🇯🇵 · Xavier Roca-Maza🇮🇹 · Tetsuo Hatsuda🇯🇵

    An approach is proposed to link the charge symmetry breaking (CSB) nuclear interaction and the low-energy constants in quantum chromodynamics (QCD) by matching the CSB effect in nuclear matter. The resulting CSB interaction is applied to study the Okamoto-Nolen-Schiffer anomaly, still lacking a satisfactory microscopic understanding, on the energy differences of mirror nuclei by taking ${}^{17}\mathrm{F}$-${}^{17}\mathrm{O}$, ${}^{15}\mathrm{O}$-${}^{15}\mathrm{N}$, ${}^{41}\mathrm{Sc}$-${}^{41}\mathrm{Ca}$, and ${}^{39}\mathrm{Ca}$-${}^{39}\mathrm{K}$ as typical examples. The magnitude and sign of the QCD-based CSB interactions are found to resolve the anomaly successfully within theoretical uncertainties.

    ↳ nucl-thhep-lathep-phnucl-exPRC(2024)·11 citations
19. 19*

    Neutralizing Topological Obstructions to Bubbles of Nothing

    Patrick Draper🇺🇸 · Benjamin Lillard🇺🇸 · Carissa Skye🇺🇸

    Theories with compact extra dimensions can exhibit a vacuum instability known as a bubble of nothing. These decay modes can be obstructed if the internal manifold is stabilized by fluxes, or if it carries Wilson lines for background gauge fields, or if the instanton is incompatible with the spin structure. In each of these cases the decay can proceed by adding dynamical charged membranes or gauge fields. We give a general, bottom-up procedure for constructing approximate bubble of nothing solutions in models with internal spheres stabilized by flux and study the influence of the brane tension on the tunneling exponent, finding two branches of solutions that merge at a minimal superextremal value of the tension. In the case of Wilson operators and incompatible fermions, the relevant bubble is shown to be the Euclidean Reissner-Nordstrom black hole, and the ordinary decay exponent is modified by $1/g^2$ effects. We examine the Dirac operator on this background and comment on the relevance for models of supergravity with gauged $R$-symmetry.

    ↳ hep-thgr-qchep-phJHEP(2023)·4 citations
20. 20*

    Highly asymmetric probability distribution from a finite-width upward step during inflation

    Ryodai Kawaguchi🇯🇵 · Tomohiro Fujita🇯🇵 · Misao Sasaki🇯🇵

    We study a single-field inflation model in which the inflaton potential has an upward step between two slow-roll regimes by taking into account the finite width of the step. We calculate the probability distribution function (PDF) of the curvature perturbation $P[\mathcal{R}]$ using the $\delta N$ formalism. The PDF has an exponential-tail only for positive $\mathcal{R}$ whose slope depends on the step width. We find that the tail may have a significant impact on the estimation of the primordial black hole abundance. We also show that the PDF $P[\mathcal{R}]$ becomes highly asymmetric on a particular scale exiting the horizon before the step, at which the curvature power spectrum has a dip. This asymmetric PDF may leave an interesting signature in the large scale structure such as voids.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2023)·32 citations
21. 21*

    ICTP Lectures on (Non-)Invertible Generalized Symmetries

    Sakura Schafer-Nameki🇬🇧

    What comprises a global symmetry of a Quantum Field Theory (QFT) has been vastly expanded in the past 10 years to include not only symmetries acting on higher-dimensional defects, but also most recently symmetries which do not have an inverse. The principle that enables this generalization is the identification of symmetries with topological defects in the QFT. In these lectures, we provide an introduction to generalized symmetries, with a focus on non-invertible symmetries. We begin with a brief overview of invertible generalized symmetries, including higher-form and higher-group symmetries, and then move on to non-invertible symmetries. The main idea that underlies many constructions of non-invertible symmetries is that of stacking a QFT with topological QFTs (TQFTs) and then gauging a diagonal non-anomalous global symmetry. The TQFTs become topological defects in the gauged theory called (twisted) theta defects and comprise a large class of non-invertible symmetries including condensation defects, self-duality defects, and non-invertible symmetries of gauge theories with disconnected gauge groups. We will explain the general principle and provide numerous concrete examples. Following this extensive characterization of symmetry generators, we then discuss their action on higher-charges, i.e. extended physical operators. As we will explain, even for invertible higher-form symmetries these are not only representations of the $p$-form symmetry group, but more generally what are called higher-representations. Finally, we give an introduction to the Symmetry Topological Field Theory (SymTFT) and its utility in characterizing symmetries, their gauging and generalized charges. Lectures prepared for the ICTP Trieste Spring School, April 2023.

    ↳ hep-thcond-mat.str-elhep-phmath.CTPhys.Rept.(2024)·465 citations
22. 22*

    The nonequilibrium evolution near the phase boundary

    Xiaobing Li🇨🇳 · Yuming Zhong🇨🇳 · Ranran Guo🇹🇼 · Mingmei Xu🇨🇳 · Yu Zhou🇯🇵 · Jinghua Fu🇨🇳 · Yuanfang Wu🇨🇳

    Using the single-spin flipping dynamics, we study the nonequilibrium evolution near the entire phase boundary of the 3D Ising model, and find that the average of relaxation time (RT) near the first-order phase transition line (1st-PTL) is significantly larger than that near the critical point (CP). As the system size increases, the average of RT near the 1st-PTL increases at a higher power compared to that near the CP. We further show that RT near the 1st-PTL is not only non-self-averaging, but actually self-diverging: relative variance of RT increases with system size. The presence of coexisting and metastable states results in a substantial increase in randomness near the 1st-PTL, and therefore makes the equilibrium more difficult to achieve.

    ↳ cond-mat.stat-mechhep-ph1 citation
23. 23*

    Dark matter vorticity and velocity dispersion from truncated Dyson$–$Schwinger equations

    Alaric Erschfeld🇩🇪 · Stefan Floerchinger🇩🇪

    Large-scale structure formation is studied in a kinetic theory approach, extending the standard perfect pressureless fluid description for dark matter by including the velocity dispersion tensor as a dynamical degree of freedom. The evolution of power spectra for density, velocity and velocity dispersion degrees of freedom is investigated in a non-perturbative approximation scheme based on the Dyson$–$Schwinger equation. In particular, the generation of vorticity and velocity dispersion is studied and predictions for the corresponding power spectra are made, which qualitatively agree well with results obtained from $N$-body simulations. It is found that velocity dispersion grows strongly due to non-linear effects and at late times its mean value seems to be largely independent of the initial conditions. By taking this into account, a rather realistic picture of non-linear large-scale structure formation can be obtained, albeit the numerical treatment remains challenging, especially for very cold dark matter models.

    ↳ astro-ph.COhep-phJCAP(2024)·7 citations
24. 24*

    Gravitational Pair Production and Black Hole Evaporation

    Michael F. Wondrak🇳🇱 · Walter D. van Suijlekom🇳🇱 · Heino Falcke🇳🇱

    We present a new avenue to black hole evaporation using a heat-kernel approach analogous as for the Schwinger effect. Applying this method to an uncharged massless scalar field in a Schwarzschild spacetime, we show that spacetime curvature takes a similar role as the electric field strength in the Schwinger effect. We interpret our results as local pair production in a gravitational field and derive a radial production profile. The resulting emission peaks near the unstable photon orbit. Comparing the particle number and energy flux to the Hawking case, we find both effects to be of similar order. However, our pair production mechanism itself does not explicitly make use of the presence of a black hole event horizon.

    ↳ gr-qcastro-ph.HEhep-phhep-thPRL(2023)·47 citations
25. 25*

    Spinning Partial Waves for Scattering Amplitudes in $d$ Dimensions

    Ilija Buric🇮🇹 · Francesco Russo🇮🇹 · Alessandro Vichi🇮🇹

    Partial wave decomposition is one of the main tools within the modern S-matrix studies. We present a method to compute partial waves for $2\to 2$ scattering of spinning particles in arbitrary spacetime dimension. We identify partial waves as matrix elements of the rotation group with definite covariance properties under a subgroup. This allows to use a variety of techniques from harmonic analysis in order to construct a novel algebra of weight-shifting operators. All spinning partial waves are generated by the action of these operators on a set of known scalar seeds. The text is accompanied by a {\it Mathematica} notebook to automatically generate partial waves. These results pave the way to a systematic studies of spinning S-matrix bootstrap and positivity bounds.

    ↳ hep-thhep-phmath-phmath.MPJHEP(2023)·17 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.