We show how weakly supervised machine learning can improve the sensitivity of LHC mono-jet searches to new physics models with anomalous jet dynamics. The Classification Without Labels (CWoLa) method is used to extract all the information available from low-level detector information without any reference to specific new physics models. For the example of a strongly interacting dark matter model, we employ simulated data to show that the discovery potential of an existing generic search can be boosted considerably.
We determine the pressure of a cold and dense electron gas to a nearly complete next-to-next-to-next-to-leading order (N3LO) in the fine-structure constant αe, utilizing a new result for the two-loop photon self-energy from a companion paper. Our result contains all infrared-sensitive contributions to the pressure at this order, including the coefficient of the O(αe3lnαe) term, and leaves only a single coefficient associated with the contributions of unresummed hard momenta undetermined. Moreover, we explicitly demonstrate the complete cancellation of infrared divergences according to the effective field theory paradigm by determining part of the hard contributions at this order. Our calculation provides the first improvement to a 45-year-old milestone result and demonstrates the feasibility of the corresponding N3LO calculation for cold and dense quark matter.
We study the gravitational production of dark photon dark matter during inflation, when dark photons acquire mass by the Higgs mechanism. In the previous study, it was assumed that the dark photon has a Stückelberg mass, or a mass generated by the Higgs mechanism with a sufficiently heavy Higgs boson. In this paper we consider a case in which the Higgs boson is not fully decoupled; the Higgs field changes its vacuum expectation value after inflation. Then, the dark photon mass also changes with time after inflation, and the time evolution of the longitudinal mode is different from the case with a Stückelberg mass. Consequently, the spectrum of the dark photon energy density can have two peaks at an intermediate scale and a small scale. We show that the dark photon can explain the dark matter if its current mass is larger than 6μeV×(HI/1014GeV)−4 and smaller than 0.8GeV×(HI/1014GeV)−3/2, with HI being the Hubble parameter during inflation. A higher mass is required if one considers a larger gauge coupling constant. The result for the Stückelberg mass can be reproduced in the limit of a small gauge coupling constant. We also comment on the constraints set by various conjectures in quantum gravity theory.
We revisit the problem of small Bjorken-x evolution of the gluon and flavor-singlet quark helicity distributions in the shock wave (s-channel) formalism. Earlier works on the subject in the same framework resulted in an evolution equation for the gluon field-strength F12 and quark "axial current" ψˉγ+γ5ψ operators (sandwiched between the appropriate light-cone Wilson lines) in the double-logarithmic approximation (DLA: summing powers of αsln2(1/x) with αs the strong coupling constant). In this work, we observe that an important mixing of the above operators with another gluon operator, DiDi, also sandwiched between the light-cone Wilson lines (with the repeated index i=1,2 summed over), was missing in the previous works. This operator has the physical meaning of the sub-eikonal (covariant) phase: its contribution to helicity evolution is shown to be proportional to another sub-eikonal operator, Di−Di, which is related to the Jaffe-Manohar polarized gluon distribution. In this work we include this operator into small-x helicity evolution, and construct a novel evolution mixing all three operators (Di−Di, F12, and ψˉγ+γ5ψ), generalizing the previous results. We also construct closed DLA evolution equations in the large-Nc and large-Nc&Nf limits, with Nc and Nf the numbers of quark colors and flavors, respectively. Solving the large-Nc equations numerically we obtain the following small-x asymptotics of the quark and gluon helicity distributions ΔΣ and ΔG, along with the g1 structure function, \[\Delta\Sigma(x,Q^2)\sim\Delta G(x,Q^2)\sim g_1(x,Q^2)\sim\left(\frac{1}{x}\right)^{3.66\,\sqrt{\frac{\alpha_s\,N_c}{2\pi}}},\] in complete agreement with the earlier work by Bartels, Ermolaev and Ryskin.
We calculate the three-loop master integrals of Ref. [1] [arXiv:1709.02160] in analytic form. This allows us to present the fermionic contributions to the ΔB=2 Wilson coefficients of the B-Bˉ decay matrix in next-to-next-to-leading order of QCD with full analytic dependence on the mass of the charm quark in the fermionic loops.
We perform the first global and unitary analysis of e+e−→bbˉ cross sections. We analyze exclusive cross sections in the BBˉ, B∗Bˉ(+c.c.), B∗Bˉ∗, Bs∗Bˉs∗, Υ(nS)π+π− and hb(nP)π+π− channels as well as the total inclusive cross section for bbˉ production. Pole positions and residues are determined for four vector states, which we associate with the Υ(4S), Υ(10750), Υ(5S) (or Υ(10860)), and Υ(6S) (or Υ(11020)). We find strong evidence for the new Υ(10750) recently claimed by Belle, although with parameters not well constrained by the data. Results presented here cast doubt on the validity of branching ratios reported earlier using Breit-Wigner parameterizations or ratios of cross sections. We also compare our results with a selection of theoretical calculations for the vector bottomonium spectrum.
We provide an extensive study of the lifetimes of singly charmed baryons and mesons, within the heavy quark expansion with all known corrections included. A special attention is devoted to the choice of the charm mass and wavefunctions of heavy baryons. We give our predictions for lifetimes, lifetime ratios, and semileptonic branching ratios of singly charmed baryons. Our results accommodate the experimentally-favoured hierarchy of singly charmed baryon lifetimes \begin{eqnarray*} \tau\left(\Xi_c^{0}\right) < \tau\left(\Lambda_c^{+}\right)< \tau\left(\Omega_c^{0}\right) < \tau\left(\Xi_c^{+}\right)\, \end{eqnarray*} in contrast to earlier theoretical findings. Predictions for charmed meson lifetimes and semileptonic decay rates are in agreement with a recent comprehensive study and experimental results within uncertainties.
The CDF-II collaboration's recent high-precision measurement of W boson mass indicates new physics contribution(s) beyond the Standard Model. We investigate the possibility of the well-known canonical Scotogenic model to explain the CDF-II measurement. The Scotogenic model is a popular scenario beyond the Standard Model that induces neutrino masses at the 1-loop level and includes a viable dark matter candidate, either scalar or fermionic. For both scalar and fermionic dark matter possibilities, we simultaneously examine the constraints coming from (a) neutrino mass, oscillation, neutrinoless double beta decay and lepton flavour violation experiments, (b) from LEP and LHC (c) from dark matter relic density and direct detection experiments (d) from the oblique S,T,U parameter values consistent with CDF-II W boson measurement. We demonstrate that the new CDF-II measurement rules out the feasible parameter space of the scalar dark matter in the high mass regions (mηR≳500GeV), while still allowing the intermediate mass regions 54GeV≲mηR≲76GeV. We also showed that the fermionic dark matter candidate in the canonical Scotogenic model, in the range MN1≲500GeV , can simultaneously explain all the aforementioned issues. Furthermore, we investigated how the recent findings from ATLAS 2023 impact this study.
We present the {\tt KKMCee 5.00.2} Monte Carlo event generator for lepton and quark pair production for the high energy electron-positron annihilation process. It is still the most sophisticated event generator for such processes. Its entire source code is re-written in the modern C++ language. It reproduces all features of the older \kkmc\ code in Fortran 77. However, a number of improvements in the Monte Carlo algorithm are also implemented. Most importantly, it is intended to be a starting point for the future improvements, which will be mandatory for the future high precision lepton collider projects. As in the older version, in addition to higher order QED corrections, it includes so-called \order{\alpha^{1.5}} genuine weak corrections using a version of the classic {\tt DIZET} library and polarized τ decays using {\tt TAUOLA} program. Both {\tt DIZET} and {\tt TAUOLA} external libraries are still in Fortran 77. In addition, a {\tt HEPMC3} interface to other MC programs, like parton showers and detector simulation, replaces the older {\tt HepEvt} interface. The {\tt HEPMC3} interface is also exploited in the implementation of the additional photon final state emissions in τ decays using an external {\tt PHOTOS} library rewritten in C.
We investigate the impact of sterile neutrinos on the decay rate of extra Z′s with mass in the TeV range in heterotic string derived models. We explore the impact of sterile neutrinos on the current Z′ mass exclusion limits at the LHC, and how these bounds change when the parameter space of this specific class of models is modified.
We consider the implication of the recent measurement of the W-boson mass MW [Science 376, 170 (2022)] for atomic parity violation experiments. We show that the change in MW shifts the Standard Model prediction for the 133Cs nuclear weak charge to QW(133Cs)=−72.85(6), i.e. by 5.5σ from its current value. This brings existing experimental result for QW(133Cs) into an essential agreement with the Standard Model. Using our revised value for QW(133Cs), we readjust constraints on physics beyond the Standard Model.
Here we review empirical evidence for the possible existence of tachyons, superluminal particles having m^2 < 0: The review considers searches for new particles that might be tachyons, as well as evidence that neutrinos are tachyons from data which may have been gathered for other purposes. Much of the second half of the paper is devoted to the 3 + 3 neutrino model including a tachyonic mass state, which has empirical support from a variety of areas. Although this is primarily a review article, it contains several new results.
Motivated by the new CDF measurement of the W boson mass reported recently which clearly illustrates a large deviation compared to the Standard Model (SM) prediction. In the present paper, we study the Two-Higgs Doublet Model (2HDM) contributions to MW and its phenomenological implications in the case where the heavy CP-even H is identified as the observed Higgs boson with a mass of 125 GeV. Taking into account theoretical and all the available experimental constraints as well as the new CDF measurement, we demonstrate that the 2HDM parameter space can provide a large correction which predicts the W mass close to the new CDF MW measurement. It is found that MH±=MA is excluded and the splitting of the charged Higgs boson with all other states is positive. We also discuss the consequence on the effective mixing angle sin2θeff as well as the phenomenological implications on the charged Higgs and CP-odd decays.
The interactions of Dˉ(∗)Λc−Dˉ(∗)Σc(∗) are studied within the framework of a dynamical coupled-channel approach. A series of bound states and resonances with different spin and parity are dynamically generated in the hidden charm sector. Four S-wave bound states are found in the mass range of 4.3 to 4.5 GeV, close to the pentaquark states observed by LHCb. Two of the states have a spin parity of JP=1/2− and the other two have JP=3/2−. In addition, several resonances with different spin and parity in higher partial waves are predicted.
We study the anomalous ttˉZ couplings in the ttˉZ production in leptonic final state at the 13 TeV LHC. We use the polarizations of top quarks and Z boson, two-body and three-body spin correlations among the top quarks and Z boson, and the cross section to probe the anomalous couplings. We estimate one parameter and simultaneous limits on the couplings of the effective vertex as well as the effective operators for a set of luminosities 150 fb−1, 300 fb−1, 1000 fb−1, and 3000 fb−1. The polarizations and the spin correlations are found to be helpful on top of the cross section to better constrain the anomalous couplings.
In recent years, exciting (indirect) hints for physics beyond the Standard Model (SM) have been accumulated. In particular, semi-leptonic B decays show deviations from the SM predictions, which, due to the ratios R(K(∗)) and R(D(∗)) are obviously related to lepton flavour universality violation (LFUV). However, {we point out} there are more anomalies which admit an interpretation in terms of LFUV: The anomalous magnetic moment of the muon, the Cabibbo angle anomaly, the CMS measurements of non-resonant di-electrons, the difference of the forward-backward asymmetry in B→D∗ℓν and leptonic tau decays. In this letter we discuss the experimental and theoretical status of these anomalies, {compare their strength and weaknesses} and examine {and synthesize} how they can be explained in terms of possible extensions of the SM by new particles and interactions. Even though not all anomalies might be confirmed in the future, this unified view of the anomalies in terms of LFUV significantly strengthens their relevance, which is crucial in order to construct a convincing physics case for future colliders.
We have previously investigated joint ΛΛˉ decay in the reaction e+e−→γΛ(→pπ−)Λˉ(→pˉπ+). The cross-section-distribution functions encountered were relativistically covariant and expressed in terms of scalar products of the four-momentum vectors of the particles involved. In the present, sequel investigation, we show that by working with three-momentum scalars instead results could possibly become more transparant.
Anomaly detection through employing machine learning techniques has emerged as a novel powerful tool in the search for new physics beyond the Standard Model. Historically similar to the development of jet observables, theoretical consistency has not always assumed a central role in the fast development of algorithms and neural network architectures. In this work, we construct an infrared and collinear safe autoencoder based on graph neural networks by employing energy-weighted message passing. We demonstrate that whilst this approach has theoretically favourable properties, it also exhibits formidable sensitivity to non-QCD structures.
We consider the charge asymmetry in the differential cross section of the process e+e−→π+π−. Experimental data show large deviations from the results of the available theoretical calculations. Motivated by this fact, we revisit the contribution of the two photon exchange diagrams and find the origin of discrepancy in an oversimplified account of the pion internal structure in the theoretical calculations. We present a natural and simple approach that accounts for the pion structure in a more consistent way and find remarkable agreement with the experimental data.
Scattering amplitudes are often split up into their color (su(N)) and kinematic components. Since the su(N) gauge part can be described using flows of color, one may anticipate that the double su(2) kinematic part can be described in terms of flows of chirality. In two recent papers we showed that this is indeed the case, introducing the chirality-flow formalism for standard model calculations. Using the chirality-flow method -- which builds on and further simplifies the spinor-helicity formalism -- Feynman diagrams can be directly written down in terms of Lorentz-invariant spinor inner products, allowing the simplest and most direct path from a Feynman diagram to a complex number. In this presentation, we introduce this method and show some examples.
We study the lepton flavor violation (LFV), the leptonic magnetic moments (g−2)μ,e and the electric dipole moment (EDM) of the electron in the Standard-Model Effective Field Theory with the ΓN modular flavor symmetry. We employ the stringy Ansatz on coupling structure that 4-point couplings of matter fields are written by a product of 3-point couplings of matter fields. We take the level 3 finite modular group, Γ3 for the flavor symmetry, and discuss the dipole operators at nearby fixed point τ=i, where observed lepton masses and mixing angles are well reproduced. Suppose the anomaly of the anomalous magnetic moment of the muon to be evidence of the new physics (NP), we have related it with (g−2)e, LFV decays, and the electron EDM. It is found that the NP contribution to (g−2)e is proportional to the lepton masses squared likewise the naive scaling. We also discuss the correlations among the LFV processes μ→eγ, τ→μγ and τ→eγ, which are testable in the future. The electron EDM requires the tiny imaginary part of the relevant Wilson coefficient in the basis of real positive charged lepton masses, which is related to the μ→eγ transition in our framework.
Wide field-of-view gamma-ray observatories must fight the overwhelming cosmic ray background to identify very-high-energy astrophysical gamma-ray events. This work introduces a novel gamma/hadron discriminating variable, LCm, which quantifies the azimuthal non-uniformity of the particle distributions at the ground. This non-uniformity, due to the presence of hadronic sub-showers, is higher in proton-induced showers than in gamma showers. The discrimination power of this new variable is then discussed, as a function of the air shower array fill factor, in the energy range 10TeV to 1PeV, and compared to the classical gamma/hadron discriminator based on the measurement of the number of muons at the ground. The results obtained are extremely encouraging, paving the way for the use of the proposed quantity in present and future large ground-array gamma-ray observatories.
The three pentaquark states, Pc(4312), Pc(4440) and Pc(4457), discovered by the LHCb Collaboration in 2019, are widely recognized as Dˉ(∗)Σc hadronic molecules. Together with their four Dˉ(∗)Σc∗ partners dictated by heavy quark spin symmetry they present a complete multiplet of hadronic molecules of Dˉ(∗)Σc(∗). It is widely recognized that to understand their nature, other discovery channels play an important role. In this work, we investigate two three-body decay modes of the Dˉ(∗)Σc(∗) molecules. The tree-level modes proceed via off-shell Σc(∗) baryons, Dˉ(∗)Σc(∗)→Dˉ(∗)(Σc(∗)→Λcπ)→Dˉ(∗)Λcπ, while the triangle-loop modes proceed through Dˉ∗Σc(∗)→J/ψNπ, ηcNπ via DˉΣc(∗) rescattering to J/ψN and ηcN. Our results indicate that the decay widths of the Pc(4457) and Dˉ(∗)Σc∗ states into Dˉ(∗)Λcπ are several MeV, as a result can be observed in the upcoming Run 3 and Run 4 of LHC. The partial decay widths into Dˉ(∗)Λcπ of the Pc(4312) and Pc(4440) states range from tens to hundreds of keV. In addition, the partial decay widths of Dˉ∗Σc molecules into J/ψNπ and ηcNπ are several keV and tens of keV, respectively, and the partial decay widths of Dˉ∗Σc∗ molecules into J/ψNπ vary from several keV to tens of keV. These three-body decay modes of the pentaquark states are of great value to further observations of the pentaquark states and to a better understanding of their nature.
The extraction of the W-boson mass, a fundamental parameter of the Standard Model, from hadron-hadron collision requires precise theory predictions. In this regard, angular coefficients are crucial to model the dynamics of W-boson production. In this work, we provide, for the first time, angular coefficients at NNLO QCD + NLO EW accuracy for finite transverse momentum W-boson at the LHC. The corrections can reach up to 10% in certain regions of phase space. They are accompanied by a significant reduction of the scale uncertainty. This work should, besides providing reference values for theory-data comparison, provide state-of-the-art theory input for W-boson mass measurements.
New coloured scalars in the Manohar-Wise model give sizeable contributions to the Electric Dipole Moment (EDM) of the neutron through one-loop and two-loop diagrams, computed in Reference [1]. Contributions from neutral scalars cancel out for degenerate values of the masses, whose difference is related to the oblique parameters S and T. The Manohar-Wise model is able to explain the recent value of the W-boson mass published by the CDF collaboration. We show, however, that the case of total degeneracy of masses is strongly disfavoured in this model, whose parameter space is substantially reduced when considering also unitarity bounds.
A necessary ingredient for extending the BFKL equation to next-to-next-to-leading logarithmic (NNLL) accuracy is the one-loop central emission vertex (CEV) for two gluons which are not strongly ordered in rapidity. Here we consider the one-loop six-gluon amplitude in N=4 super Yang-Mills (SYM) theory in a central next-to-multi-Regge kinematic (NMRK) limit, we show that its dispersive part factorises in terms of the two-gluon CEV, and we use it to extract the one-loop two-gluon CEV for any helicity configuration within this theory. This is a component of the two-gluon CEV in QCD. Although computed in the NMRK limit, both the colour structure and the kinematic dependence of the two-gluon CEV capture much of the complexity of the six-gluon amplitudes in general kinematics. In fact, the transcendental functions of the latter can be conveniently written in terms of impact factors, trajectories, single-emission CEVs and a remainder, which is a function of the conformally invariant cross ratios which characterise the six-gluon amplitudes in planar N=4 SYM. Finally, as expected, in the MRK limit the two-gluon CEV neatly factorises in terms of two single-emission CEVs.
We consider dark sector scenarios where dark matter is accompanied by a dark photon and multiple-flavor dark fermions charged under the dark gauge group. We study quantum interference effects in dark sector jets, where multiple dark photons are emitted from high-energy dark fermions. We perform fully quantum simulations of dark sector showers and compare the results against those of the classical Monte-Carlo simulations. We find important differences in probability distributions of dark photon countings between quantum and classical computations. When the number of dark-fermion flavors is large, we find significant enhancements in large numbers of dark photon emissions. Such enhancements can provide distinguishing signals for our scenarios at particle colliders.
We explore a simple but extremely predictive extension of the scotogenic model. We promote the scotogenic symmetry Z2 to the flavour non-Abelian symmetry Σ(81), which can also automatically protect dark matter stability. In addition, Σ(81) leads to striking predictions in the lepton sector: only Inverted Ordering is realised, the absolute neutrino mass scale is predicted to be mlightest≈7.5×10−4 eV and the Majorana phases are correlated in such a way that ∣mee∣≈0.018 eV. The model also leads to a strong correlation between the solar mixing angle θ12 and δCP, which may be falsified by the next generation of neutrino oscillation experiments. The setup is minimal in the sense that no additional symmetries or flavons are required.
We bootstrap the three-point form factor of the chiral stress-tensor multiplet in planar N=4 supersymmetric Yang-Mills theory at six, seven, and eight loops, using boundary data from the form factor operator product expansion. This may represent the highest perturbative order to which multi-variate quantities in a unitary four-dimensional quantum field theory have been computed. In computing this form factor, we observe and employ new restrictions on pairs and triples of adjacent letters in the symbol. We provide details about the function space required to describe the form factor through eight loops. Plotting the results on various lines provides striking numerical evidence for a finite radius of convergence of perturbation theory. By the principle of maximal transcendentality, our results are expected to give the highest weight part of the gg→Hg and H→ggg amplitudes in the heavy-top limit of QCD through eight loops. These results were also recently used to discover a new antipodal duality between this form factor and a six-point amplitude in the same theory.
This note presents a method to reduce the discretization errors appearing when solving a Quantum Field Theory in a hypercubic lattice in both position and momentum-space. The method exploits the artifacts that break rotational symmetry to recover rotationally invariant results for two-point Green functions. We show that a combination of the results obtained in position and momentum space can be useful to signal the presence of rotationally invariant artifacts making use of their approximate Fourier transforms in the continuum. The method will be introduced using a Klein-Gordon propagator, and a direct application to gluon propagator in quenched lattice QCD will be given.
We extend our previous work on the light-quark connected part, aμHVP,lqc, of the leading order hadronic-vacuum-polarization (HVP) contribution to the muon anomalous magnetic moment aμ, using staggered fermions, in several directions. We have collected more statistics on ensembles with lattice spacings of 0.06, 0.09 and 0.12 fm, and we added two new ensembles, both with lattice spacing 0.15 fm, but with different volumes. The increased statistics allow us to reduce statistical errors on aμHVP,lqc and related window quantities significantly. We also calculate the current-current correlator from which aμHVP,lqc is obtained to next-to-next-to-leading order (NNLO) in staggered chiral perturbation theory, so that we can correct lattice values for aμHVP,lqc to NNLO for finite-volume, pion-mass mistuning and taste-breaking effects. We discuss the applicability of NNLO chiral perturbation theory to aμHVP,lqc and to the window quantities, emphasizing that it provides a systematic EFT approach to aμHVP,lqc, but not to short- or intermediate-distance window quantities. This makes it difficult to assess systematic errors on the standard intermediate-distance window quantity that is now widely considered in the literature. In view of this, we investigate a longer-distance window, for which EFT methods should be more reliable. Our most important conclusion is that, especially for staggered fermions, new high-statistics computations at lattice spacings smaller than 0.06 fm are indispensable.
Compton scattering is a key process shaping spectra formation and accretion flow dynamics in accreting strongly magnetized neutron stars. A strong magnetic field affects the scattering cross section and makes it dependent on photon energy, momentum, and polarization state. Using Monte Carlo simulations, we investigate statistical features of Compton scattering of polarized X-ray radiation in a strong magnetic field. Our analysis is focused on photon gas behaviour well inside the scattering region. We take into account the resonant scattering at the fundamental cyclotron frequency, thermal distribution of electrons at the ground Landau level, and bulk velocity of the electron gas. We show that (i) the photons scattered around the cyclotron energy by the electron gas at rest tend to acquire the final energy close to the cyclotron one with a very small dispersion measure; (ii) the redistribution of photons within the Doppler core of cyclotron resonance differs significantly from the complete redistribution; (iii) the efficiency of momentum transfer from photons to the electron gas is affected by the temperature of electron gas both for photons at cyclotron energy and below it; (iv) the momentum transfer from photons to the electron gas of non-zero bulk velocity is more efficient in the case of magnetic scattering.
In this paper, we investigate the quantum coherence for two flavor neutrinos propagating in a Schwarzschild metric. In fact, this issue is explored both qualitatively via calculating the parameter K3 in Leggett-Garg inequality (LGI) and also quantitatively by evaluating the l1-norm, C(ρ). Using the weak field approximations, we show that the gravitational effects decrease the maximum value of K3 for some intervals of energy such a way that there is no violation, while it leaves the maximum amount of the quantum coherence, C(ρ) unchanged.
A closer and more detailed study of neutrino oscillation, in addition to assisting us in founding physics beyond the standard model, can potentially be used to understand the fundamental aspects of quantum mechanics. In particular, we know that the neutrino oscillation occurs because the quantum states of the produced and detected neutrinos are a coherent superposition of the mass eigenstates, and this coherency is maintained during the propagation due to the small mass difference of neutrinos. In this paper, we consider the decoherence due to the neutrino interaction in the material medium with constant density in addition to the decoherence coming from the localization properties. For this purpose, we use l1-norm in order to quantify the coherence and investigate its dependence on the matter density. According to our results, in general, the coherence in material medium is less than vacuum. However, there exist exceptions; for some matter densities, the localization coherence lengths become infinite. So, for these cases, l1-norm in matter is more than the vacuum.
Experimental refinements and technical innovations in the field of extensive air shower telescopes have enabled measurements of Galactic cosmic-ray interactions in the sub-PeV range, providing new avenues for the search for new physics and dark matter. For the first time, we exploit sub-PeV (1 TeV -- 1 PeV) observations of Galactic diffuse gamma rays by HAWC and Tibet ASγ to search for an axion-like-particle (ALP) induced gamma-ray signal directly linked to the origin of the IceCube extragalactic high-energy neutrino flux. Indeed, the production of high-energy neutrinos in extragalactic sources implies the concomitant production of gamma rays at comparable energies. Within the magnetic field of the neutrino emitting sources, gamma rays may efficiently convert into ALPs, escape their host galaxy un-attenuated, propagate through intergalactic space, and reconvert into gamma rays in the magnetic field of the Milky Way. Such a scenario creates an all-sky diffuse high-energy gamma-ray signal in the sub-PeV range. Accounting for the guaranteed Galactic astrophysical gamma-ray contributions from cosmic-ray interactions with gas and radiation and from sub-threshold sources, we set competitive upper limits on the photon-ALP coupling constant gaγγ. We find gaγγ<2.1×10−11 GeV−1 for ALP masses ma≤2×10−7 eV at a 95\% confidence level. Our results are comparable to previous limits on ALPs derived from the TeV gamma-ray domain and progressively close the mass gap towards ADMX limits. The code and data to reproduce the results of this study are available on GitHub \url{https://github.com/ceckner/subPeVALPs}.
Black holes located within a dark matter cloud can create overdensity regions known as dark matter spikes. The presence of spikes modifies the gravitational-wave signals from binary systems through changes in the gravitational potential or dynamical friction effects. We assess the importance of including relativistic effects in both the dark matter distribution and the dynamical friction. As a first step we numerically calculate the particle dark matter spike distribution in full general relativity, using both Hernquist and Navarro-Frenk-White profiles in a Schwarzschild background, and we produce analytical fits to the spike profiles for a large range of scale parameters. Then we use a post-Newtonian prescription for the gravitational-wave dephasing to estimate the effect of relativistic corrections to the spike profile and to the dynamical friction. Finally we include the torques generated by dynamical friction in fast-to-generate relativistic models for circular extreme mass-ratio inspirals around a nonspinning black hole. We find that both types of relativistic corrections positively impact the detectability of dark matter effects, leading to higher dephasings and mismatches between gravitational-wave signals with and without dark matter spikes.
↳ gr-qcastro-ph.HEhep-phPRD(2022)·112 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.