Thu·Dec 17, 2020Thursday·December 17, 2020

1. 01*

   Saturation effects in SIDIS at very forward rapidities

   E. Iancu🇫🇷 · A.H. Mueller🇺🇸 · D.N. Triantafyllopoulos🇮🇹 · S.Y. Wei🇮🇹

   Using the dipole picture for electron-nucleus deep inelastic scattering at small Bjorken $x$, we study the effects of gluon saturation in the nuclear target on the cross-section for SIDIS (single inclusive hadron, or jet, production). We argue that the sensitivity of this process to gluon saturation can be enhanced by tagging on a hadron (or jet) which carries a large fraction $z\simeq 1$ of the longitudinal momentum of the virtual photon. This opens the possibility to study gluon saturation in relatively hard processes, where the virtuality $Q^2$ is (much) larger than the target saturation momentum $Q_s^2$, but such that $z(1-z)Q^2\lesssim Q_s^2$. Working in the limit $z(1-z)Q^2\ll Q_s^2$, we predict new phenomena which would signal saturation in the SIDIS cross-section. For sufficiently low transverse momenta $k_{\perp }\ll Q_s$ of the produced particle, the dominant contribution comes from elastic scattering in the black disk limit, which exposes the unintegrated quark distribution in the virtual photon. For larger momenta $k_{\perp }\gtrsim Q_s$, inelastic collisions take the leading role. They explore gluon saturation via multiple scattering, leading to a Gaussian distribution in $k_{\perp }$ centred around $Q_s$. When $z(1-z)Q^2\ll Q^2$, this results in a Cronin peak in the nuclear modification factor (the $R_{pA}$ ratio) at moderate values of $x$. With decreasing $x$, this peak is washed out by the high-energy evolution and replaced by nuclear suppression ($R_{pA}<1$) up to large momenta $k_{\perp }\gg Q_s$. Still for $z(1-z)Q^2\ll Q_s^2$, we also compute SIDIS cross-sections integrated over $k_{\perp }$. We find that both elastic and inelastic scattering are controlled by the black disk limit, so they yield similar contributions, of zeroth order in the QCD coupling.

   hep-phnucl-thJHEP(2021)·29 citations
2. 02*

   Uncovering hidden patterns in collider events with Bayesian probabilistic models

   Darius A. Faroughy🇨🇭

   Individual events at high-energy colliders like the LHC can be represented by a sequence of measurements, or 'point patterns' in an observable space. Starting from this data representation, we build a simple Bayesian probabilistic model for event measurements useful for unsupervised event classification in beyond the standard model (BSM) studies. In order to arrive to this model we assume that the event measurements are exchangeable (and apply De Finetti's representation theorem), the data is discrete, and measurements are generated from multiple 'latent' distributions, called 'themes'. The resulting probabilistic model for collider events is a mixed-membership model known as Latent Dirichlet Allocation (LDA), a model extensively used in natural language processing applications. By training on point patterns in the primary Lund plane, we demonstrate that a two-theme LDA model can learn to distinguish in unlabelled dijet events the hidden new physics patterns produced by a BSM signature from a much larger QCD background. Based on 1904.04200 and 2005.12319.

   hep-phPoS(2021)·19 citations
3. 03*

   Long-lived Dark Higgs and Inelastic Dark Matter at Belle II

   Michael Duerr🇩🇪 · Torben Ferber🇩🇪 · Camilo Garcia-Cely🇩🇪 · Christopher Hearty🇨🇦 · Kai Schmidt-Hoberg🇩🇪

   Inelastic dark matter is an interesting scenario for light thermal dark matter which is fully consistent with all cosmological probes as well as direct and indirect dark matter detection. The required mass splitting between dark matter ${\chi }_1$ and its heavier twin ${\chi }_2$ is naturally induced by a dark Higgs field which also provides a simple mechanism to give mass to the dark photon $A^{\prime }$ present in the setup. The corresponding dark Higgs boson $h^{\prime }$ is naturally the lightest dark sector state and therefore decays into Standard Model particles via Higgs mixing. In this work we study signatures with displaced vertices and missing momentum at Belle II, arising from dark Higgs particles produced in association with dark matter. We find that Belle II can be very sensitive to this scenario, in particular if a displaced vertex trigger is available in the near future.

   hep-phJHEP(2021)·70 citations
4. 04*

   Mixed EW-QCD leading fermionic three-loop corrections at $\mathcal{O}({\alpha }_s{\alpha }^2)$ to electroweak precision observables

   Lisong Chen🇺🇸 · Ayres Freitas🇺🇸

   Measurements of electroweak precision observables at future electron-positron colliders, such as the CEPC, FCC-ee, and ILC, will be sensitive to physics at multi-TeV scales. To achieve this sensitivity, precise predictions for the Standard Model expectations of these observables are needed, including corrections at the three- and four-loop level. In this article, results are presented for the calculation of a subset of three-loop mixed electroweak-QCD corrections, stemming from diagrams with a gluon exchange and two closed fermion loops. The numerical impact of these corrections is illustrated for a number of applications: the prediction of the W-boson mass from the Fermi constant, the effective weak mixing angle, and the partial and total widths of the Z boson. Two alternative renormalization schemes for the top-quark mass are considered, on-shell and $\overline{\text{mbox}MS}$.

   hep-phJHEP(2021)·23 citations
5. 05*

   Soft Pomeron in light of the LHC correlated data

   M. Broilo🇧🇷 · D.A. Fagundes🇧🇷 · E.G.S. Luna🇧🇷 · M. Peláez🇺🇾

   The LHC has released precise measurements of elastic proton-proton scattering that provide a unique constraint on the asymptotic behavior of the scattering amplitude at high energies. Recent reanalyses of part of these data indicate that the central values of some forward quantities would be different than initially observed. We introduce correlation information between the original and the reanalyzed data sets in a way suitable for a global fitting analysis of all data. The careful treatment of correlated errors leads to much less stringent limits on the $\rho$ uncertainty and sets up the stage for describing the forward data using a scattering amplitude dominated by only crossing-even terms. In the light of these correlated data we determine the parameters of the soft Pomeron from the Regge theory. We use Born-level and eikonalized amplitudes. In the Born-level case we estimate the contribution of the double Pomeron exchange, while in the latter case we investigate the role of the eikonalization in both the one- and two-channel models. The role of the proton-Pomeron vertex form and of the nearest $t$-channel singularity in the Pomeron trajectory receives particular attention. We discuss the implications of our results and present predictions for the total cross section and the $\rho$ parameter in proton-proton collisions at LHC and cosmic ray energies.

   hep-phhep-exhep-thPRD(2021)·13 citations
6. 06*

   Perturbative RG analysis of the condensate dependence of the axial anomaly in the three flavor linear sigma model

   G. Fejos🇭🇺

   Coupling of `t Hooft's determinant term is investigated in the framework of the three flavor linear sigma model as a function of the chiral condensate. Using perturbation theory around the minimum point of the effective action, we calculate the renormalization group flow of the first field dependent correction to the coupling of the conventional U_A(1) breaking determinant term. It is found that at low temperatures mesonic fluctuations make the anomaly increase when the chiral condensate decreases. As an application, we analyze the effect at the zero temperature nuclear liquid-gas transition.

   hep-phhep-thSymmetry(2021)·2 citations
7. 07*

   CP violation from charged Higgs bosons in the three Higgs doublet model

   Heather E. Logan🇨🇦 · Stefano Moretti🇬🇧 · Diana Rojas-Ciofalo🇬🇧 · Muyuan Song🇬🇧

   We demonstrate a new type of cancellation of contributions to the electron and neutron electric dipole moments (EDMs) that occurs in three Higgs doublet models (3HDMs) when CP violation appears in the charged Higgs sector. The cancellation becomes exact when the two physical charged Higgs bosons in the model are degenerate in mass. Depending on the model parameters, degeneracies at the 10\% level are however sufficient to evade current bounds on the electron and neutron EDMs. We demonstrate that viable parameter space remains with both charged Higgs bosons lighter than 500 GeV and large CP-violating phases while also satisfying theoretical constraints from perturbativity and experimental ones from $\bar{B}\to X_s\gamma$ and direct searches.

   hep-phJHEP(2021)·28 citations
8. 08*

   Instanton induced transverse single spin asymmetry for ${\pi }^0$ production in $pp$-scattering

   N. Korchagin (1)🇨🇳 · N. Kochelev🇨🇳 · Pengming Zhang (2) ((1) Institute of Modern Physics Chinese Academy of Sciences, Lanzhou, China, (2) School of Physics and Astronomy, Sun Yat-sen University, Zhuhai, China)🇨🇳

   We calculate the production cross-section and the transverse single-spin asymmetry for pion in $p^{\uparrow }+p\to {\pi }^0+X$. Our computation is based on existence of the instanton induced effective quark-gluon and quark-gluon-pion interactions with a strong spin dependency. In this framework we calculate the cross section without using fragmentation functions. We compare predictions of the model with data from RHIC. Our numerical results, based on the instanton liquid model for QCD vacuum, are in agreement with unpolarized cross section data. The asymmetry grows with the transverse momentum of pion $k_t$ in accordance with experimental observations. It reach value $\sim 10\%$ but at higher $k_t$ than experiment shows.

   hep-phhep-exPRD(2021)·0 citations
9. 09*

   Nucleon structure and spin effects in elastic hadron scattering

   O.V. Selyugin🇷🇺

   Soft diffraction phenomena in elastic nucleon scattering are considered from the viewpoint of the spin dependence of the interaction potential. Spin-dependent pomeron effects are analyzed for elastic $pp$ scattering, spin-dependent differential cross sections and spin correlation parameters are calculated. The spin correlation parameter $A_N$ is examined on the basis of experimental data from $\sqrt{s}=4.9GeV$ up to $23.4$GeV in the framework of the extended High Energy Generalized Structure (HEGS) model. It is shown that the existing experimental data of proton-proton and proton-antiproton elastic scattering at high energy in the region of the diffraction minimum and at large momentum transfer give the support of the existence of the energy-independent part of the hadron spin flip amplitude.

   hep-phhep-exSymmetry(2021)·1 citation
10. 10*

    Particle spectra from dark matter annihilation: physics modeling and QCD uncertainties

    Simone Amoroso🇩🇪 · Sascha Caron🇳🇱 · Adil Jueid🇰🇷 · Roberto Ruiz de Austri🇪🇸 · Peter Skands🇦🇺

    In this talk, we discuss the physics modelling of particle spectra arising from dark matter (DM) annihilation or decay. In the context of the indirect searches of DM, the final state products will, in general, undergo a set of complicated processes such as resonance decays, QED/QCD radiation, hadronisation and hadron decays. This set of processes lead to stable particles (photons, positrons, anti-protons, and neutrinos among others) which travel for very long distances before reaching the detectors. The modelling of their spectra contains some uncertainties which are often neglected in the relevant analyses. We discuss the sources of these uncertainties and estimate their impact on photon energy spectra for benchmark DM scenarios with $m_{\chi }\in [10,1000]$GeV. Instructions for how to retrieve complete tables from Zenodo are also provided.

    hep-phastro-ph.COPoS(2021)·6 citations
11. 11*

    Nucleon Structure and Strong Interactions in Dark Matter Capture in Neutron Stars

    Nicole F. Bell🇦🇺 · Giorgio Busoni🇩🇪 · Theo F. Motta🇦🇺 · Sandra Robles🇦🇺 · Anthony W. Thomas🇦🇺 · Michael Virgato🇦🇺

    We outline two important effects that are missing from most evaluations of the dark matter capture rate in neutron stars. As dark matter scattering with nucleons in the star involves large momentum transfer, nucleon structure must be taken into account via a momentum dependence of the hadronic form factors. In addition, due to the high density of neutron star matter, we should account for nucleon interactions rather than modeling the nucleons as an ideal Fermi gas. Properly incorporating these effects is found to suppress the dark matter capture rate by up to four orders of magnitude for the heaviest stars.

    hep-phastro-ph.COastro-ph.HEnucl-thPRL(2021)·98 citations
12. 12*

    Exclusive dilepton production at forward rapidities in $PbPb$ collisions

    Victor P. Goncalves🇧🇷 · Daniel E. Martins🇧🇷 · Murilo S. Rangel🇧🇷

    The dilepton production in diffractive and exclusive processes at forward rapidities considering ultraperipheral $PbPb$ collisions at the LHC is investigated. Predictions for the $e^{+}{e}^{-}$, ${\mu }^{+}{\mu }^{-}$ and ${\tau }^{+}{\tau }^{-}$ cross sections are presented taking into account of realistic cuts that can be implemented by the LHCb Collaboration in a future experimental analysis. Our results indicate that the background associated with the diffractive production can be strongly suppressed and the exclusive processes can be cleanly separated. For the ${\tau }^{+}{\tau }^{-}$ production, the semi and purely leptonic decay channels are considered. Our results indicate that a future experimental analysis of the dilepton production at the LHCb is feasible and can be useful to search for BSM physics.

    hep-phhep-exEPJC(2021)·7 citations
13. 13*

    Studying dark matter with MadDM 3.1: a short user guide

    Chiara Arina🇧🇪 · Jan Heisig🇧🇪 · Fabio Maltoni🇧🇪 · Luca Mantani🇧🇪 · Daniele Massaro🇧🇪 · Olivier Mattelaer🇧🇪 · Gopolang Mohlabeng🇨🇦

    MadDM is an automated numerical tool for the computation of dark-matter observables for generic new physics models. We announce version 3.1 and summarize its features. Notably, the code goes beyond the mere cross-section computation for direct and indirect detection. For instance, it allows the user to compute the fully differential nuclear recoil rates as well as the energy spectra of photons, neutrinos and charged cosmic rays for arbitrary $2\to n$ annihilation processes. This short user guide equips researchers with all the relevant information required to readily perform comprehensive phenomenological studies of particle dark-matter models.

    hep-phPoS(2021)·19 citations
14. 14*

    Running in the ALPs

    Mikael Chala🇪🇸 · Guilherme Guedes🇪🇸 · Maria Ramos🇪🇸 · Jose Santiago🇪🇸

    The couplings of axion-like particles are probed by different experiments across a huge range of energy scales. Accordingly, a consistent analysis of the corresponding constraints requires the use of the renormalization group equations. We compute the full one-loop renormalization group evolution of all -- relevant and marginal -- parameters in the effective field theory for axion-like particles up to dimension five, above and below the electroweak scale, assuming only that new physics does not violate CP. We also include a detailed discussion of the different bases used in the literature, the relations among them and the interplay of the CP and shift symmetries.

    hep-phEPJC(2021)·156 citations
15. 15*

    How heavy can dark matter be? Constraining colourful unitarity with SARAH

    Mark D. Goodsell🇫🇷 · Rhea Moutafis🇫🇷

    We describe the automation of the calculation of perturbative unitarity constraints including scalars that have colour charges, and its release in SARAH 4.14.4. We apply this, along with vacuum stability constraints, to a simple dark matter model with colourful mediators and interesting decays, and show how it leads to a bound on a thermal relic dark matter mass well below the classic Griest-Kamionkowski limit.

    hep-phEPJC(2021)·16 citations
16. 16*

    Equilibration of the Quark-Gluon Plasma at finite net-baryon density in QCD kinetic theory

    Xiaojian Du🇩🇪 · Sören Schlichting🇩🇪

    We explore the out-of-equilibrium dynamics of the Quark-Gluon Plasma at zero and finite net-baryon density based on an effective kinetic theory of Quantum Chromo Dynamics (QCD). By investigating the isotropization of the longitudinal pressure, we determine the relevant time and temperature scales for the onset of viscous hydrodynamics, and quantify the dependence on the chemical composition of the QGP. By extrapolating our results to realistic coupling strength, we discuss phenomenological consequences regarding the role of the pre-equilibrium phase at different collision energies.

    hep-phnucl-thPRL(2021)·62 citations
17. 17*

    Equilibration of weakly coupled QCD plasmas

    Xiaojian Du🇩🇪 · Sören Schlichting🇩🇪

    We employ a non-equilibrium Quantum Chromodynamics (QCD) kinetic description to study the kinetic and chemical equilibration of the Quark-Gluon Plasma (QGP) at weak coupling. Based on our numerical framework, which explicitly includes all leading order processes involving light flavor degrees of freedom, we investigate the thermalization process of homogeneous and isotropic plasmas far-from equilibrium and determine the relevant time scales for kinetic and chemical equilibration. We further simulate the longitudinally expanding pre-equilibrium plasma created in ultrarelativistic heavy-ion collisions at zero and non-zero density of the conserved charges and study its microscopic and macroscopic evolution towards equilibrium.

    hep-phnucl-thPRD(2021)·63 citations
18. 18*

    Freeze-in produced dark matter in the ultra-relativistic regime

    Simone Biondini🇨🇭 · Jacopo Ghiglieri🇫🇷

    When dark matter particles only feebly interact with plasma constituents in the early universe, they never reach thermal equilibrium. As opposed to the freeze-out mechanism, where the dark matter abundance is determined at $T\ll M$, the energy density of a feebly interacting state builds up and increases over $T\gtrsim M$. In this work, we address the impact of the high-temperature regime on the dark matter production rate, where the dark and Standard Model particles are ultra-relativistic and nearly light-like. In this setting, multiple soft scatterings, as well as $2\to 2$ processes, are found to give a large contribution to the production rate. Within the model we consider in this work, namely a Majorana fermion dark matter of mass $M$ accompanied by a heavier scalar $-$ with mass splitting $\Delta M$ $-$ which shares interactions with the visible sector, the energy density can be dramatically underestimated when neglecting the high-temperature dynamics. We find that the overall effective $1\leftrightarrow 2$ and $2\to 2$ high-temperature contributions to dark-matter production give $\mathcal{O}(10)$ (20\%) corrections for $\Delta M/M=0.1$ ($\Delta M/M=10$) to the Born production rate with in-vacuum masses and matrix elements. We also assess the impact of bound-state effects on the late-time annihilations of the heavier scalar, in the context of the super-WIMP mechanism.

    hep-phJCAP(2021)·38 citations
19. 19*

    Contributions of the Cartan generators in potentials between static sources

    Seyed Mohsen Hosseini Nejad🇮🇷

    We investigate the contributions of the Cartan generators in the static potentials for various representations in the framework of the domain model of center vortices for SU(3) gauge theory. Using the center domains with the cores corresponding to only one Cartan generator H8, already given as a particular proposal, leads to some concavities in the potentials for higher representations. Furthermore, the string tension of the fundamental representation is the same at Casimir scaling and N-ality regimes. We add the contribution of the other Cartan generator H3 to the potentials and therefore these shortcomings can be eliminated. However, we discuss that at intermediate range of distances the potentials induced by only H8 agree with the Casimir scaling better than those corresponding to both Cartan generators.

    hep-phInt.J.Mod.Phys.A(2021)·0 citations
20. 20*

    How to discover QCD Instantons at the LHC

    Simone Amoroso🇩🇪 · Deepak Kar🇿🇦 · Matthias Schott🇩🇪

    The Standard Model of particle physics predicts the existence of quantum tunnelling processes across topological inequivalent vacua, known as Instantons. In the electroweak sector, instantons provide a source of baryon asymmetry within the Standard Model. In Quantum Chromodynamics they are linked to chiral symmetry breaking and confinement. The direct experimental observation of Instanton-induced processes would therefore be a breakthrough in modern particle physics. Recently, new calculations for QCD Instanton processes in proton-proton collisions became public, suggesting sizable cross sections as well as promising experimental signatures at the LHC. In this work, we study possible analysis strategies to discover QCD Instanton induced processes at the LHC and derive a first limit based on existing Minimum Bias data.

    hep-phEPJC(2021)·18 citations
21. 21*

    Probing Particle Physics with Gravitational Waves

    Horng Sheng Chia🇳🇱

    The direct detection of gravitational waves offers an exciting new window onto our Universe. At the same time, multiple observational evidence and theoretical considerations motivate the presence of physics beyond the Standard Model. In this thesis, we explore new ways of probing particle physics in the era of gravitational-wave astronomy. We focus on the signatures of ultralight bosons on the gravitational waves emitted by binary systems, demonstrating how binary black holes are novel detectors of this class of dark matter. We also discuss probes of other types of new physics through their finite-size imprints on gravitational waveforms, and examine the extent to which current template-bank searches could be used to detect these signals. In the first two chapters of this thesis, we review several aspects of gravitational-wave physics and particle physics at the weak coupling frontier; we hope the reader would find these reviews helpful in delving further into the literature and in their research.

    hep-phastro-ph.COastro-ph.HEgr-qc+110 citations
22. 22*

    The role of the threshold variable in soft-gluon resummation of the $t\bar{t}h$ production process

    Melissa van Beekveld🇬🇧 · Wim Beenakker🇳🇱

    We study the role of the threshold variable in soft-gluon threshold resummation. We focus on the computation of the resummed total cross section, the final-state invariant-mass distribution, and transverse-momentum distribution of the Higgs boson when produced in association with a top-anti-top quark pair for the Large Hadron Collider operating at 13 TeV. We show that different choices for the threshold variable result in differences at next-to-leading power, i.e. contributions that are down by one power of the threshold variable. These contributions are noticeable numerically, although their effect on the resummed observables lies within the scale uncertainty of those observables. The average central results, obtained after combining several central-scale choices, agree remarkably well for different choices of the threshold variable. However, different threshold choices do effect the resulting scale uncertainty. To compute our results, we introduce a novel numerical method that we call the deformation method, which aids the stabilization of the inverse Mellin transform in cases where the analytical Mellin transform of the partonic cross section is unknown. We show that this method leads to a factor of 10 less function evaluations, while gaining a factor of 4-5 in numerical precision when compared to the standard method.

    hep-phJHEP(2021)·7 citations
23. 23*

    Dark Matter, Destroyer of Worlds: Neutrino, Thermal, and Existential Signatures from Black Holes in the Sun and Earth

    Javier F. Acevedo🇨🇦 · Joseph Bramante🇨🇦 · Alan Goodman🇨🇦 · Joachim Kopp🇨🇭 · Toby Opferkuch🇨🇭

    Dark matter can be captured by celestial objects and accumulate at their centers, forming a core of dark matter that can collapse to a small black hole, provided that the annihilation rate is small or zero. If the nascent black hole is big enough, it will grow to consume the star or planet. We calculate the rate of dark matter accumulation in the Sun and Earth, and use their continued existence to place novel constraints on high mass asymmetric dark matter interactions. We also identify and detail less destructive signatures: a newly-formed black hole can be small enough to evaporate via Hawking radiation, resulting in an anomalous heat flow emanating from Earth, or in a flux of high-energy neutrinos from the Sun observable at IceCube. The latter signature is entirely new, and we find that it may cover large regions of parameter space that are not probed by any other method.

    hep-phastro-ph.HEhep-exJCAP(2021)·74 citations
24. 24*

    Structure Formation Limits on Axion-Like Dark Matter

    Sven Baumholzer🇩🇪 · Vedran Brdar🇺🇸 · Enrico Morgante🇩🇪

    We derive structure formation limits on dark matter (DM) composed of keV-scale axion-like particles (ALPs), produced via freeze-in through the interactions with photons and Standard Model (SM) fermions. We employ Lyman-alpha (Ly-{\alpha}) forest data sets as well as the observed number of Milky Way (MW) subhalos. We compare results obtained using Maxwell-Boltzmann and quantum statistics for describing the SM bath. It should be emphasized that the presence of logarithmic divergences complicates the calculation of the production rate, which can not be parameterized with a simple power law behaviour. The obtained results, in combination with X-ray bounds, exclude the possibility for a photophilic "frozen-in" ALP DM with mass below $\sim 19\mathrm{keV}$. For the photophobic ALP scenario, in which DM couples primarily to SM fermions, the ALP DM distribution function is peaked at somewhat lower momentum and hence for such realization we find weaker limits on DM mass. Future facilities, such as the upcoming Vera C. Rubin observatory, will provide measurements with which the current bounds can be significantly improved to $\sim 80\mathrm{keV}$.

    hep-phastro-ph.COhep-thJCAP(2021)·22 citations
25. 25*

    Low Energy Effective Field Theory Operator Basis at $d\le 9$

    Hao-Lin Li🇨🇳 · Zhe Ren🇨🇳 · Ming-Lei Xiao🇨🇳 · Jiang-Hao Yu🇨🇳 · Yu-Hui Zheng🇨🇳

    We obtain the complete operator bases at mass dimensions 5, 6, 7, 8, 9 for the low energy effective field theory (LEFT), which parametrize various physics effects between the QCD scale and the electroweak scale. The independence of the operator basis regarding the equation of motion, integration by parts and flavor relations, is guaranteed by our algorithm, whose validity for the LEFT with massive fermions involved is proved by a generalization of the amplitude-operator correspondence. At dimension 8 and 9, we list the 35058 (756) and 704584 (3686) operators for three (one) generations of fermions categorized by their baryon and lepton number violations $(\Delta B,\Delta L)$, as these operators are of most phenomenological relevance.

    hep-phJHEP(2021)·66 citations
26. 26*

    HiggsSignals-2: Probing new physics with precision Higgs measurements in the LHC 13 TeV era

    Philip Bechtle🇩🇪 · Sven Heinemeyer🇪🇸 · Tobias Klingl🇩🇪 · Tim Stefaniak🇩🇪 · Georg Weiglein🇩🇪 · Jonas Wittbrodt🇸🇪

    The program HiggsSignals confronts the predictions of models with arbitrary Higgs sectors with the available Higgs signal rate and mass measurements, resulting in a likelihood estimate. A new version of the program, HiggsSignals-2, is presented that contains various improvements in its functionality and applicability. In particular, the new features comprise improvements in the theoretical input framework and the handling of possible complexities of beyond-the-SM Higgs sectors, as well as the incorporation of experimental results in the form of Simplified Template Cross Section (STXS) measurements. The new functionalities are explained, and a thorough discussion of the possible statistical interpretations of the HiggsSignals results is provided. The performance of HiggsSignals is illustrated for some example analyses. In this context the importance of public information on certain experimental details like efficiencies and uncertainty correlations is pointed out. HiggsSignals is continuously updated to the latest experimental results and can be obtained at https://www.gitlab.com/higgsbounds/higgssignals .

    hep-phhep-exEPJC(2021)·334 citations
27. 27*

    Global fits in the Aligned Two-Higgs-Doublet model

    Otto Eberhardt🇪🇸 · Ana Peñuelas Martínez🇩🇪 · Antonio Pich🇪🇸

    We present the results of a global fit to the Aligned Two-Higgs Doublet Model, assuming that there are no new sources of CP violation beyond the quark mixing matrix. We use the most constraining flavour observables, electroweak precision measurements and the available data on Higgs signal strengths and collider searches for heavy scalars, together with the theoretical requirements of perturbativity and positivity of the scalar potential. The combination of all these constraints restricts the values of the scalar masses, the couplings of the scalar potential and the flavour-alignment parameters. The numerical fits have been performed using the open-source HEPfit package.

    hep-phJHEP(2021)·58 citations
28. 28*

    Exploring the possible gluon condensation signature in gamma-ray emission from pulsars

    J.H. Ruan🇨🇳 · Z.C. Zheng🇨🇳 · W. Zhu🇨🇳

    The very high energy gamma-ray emissions from pulsars are usually considered to be dominated by leptonic scenario since the hadronic flux is weak. We point out that the gluon condensation predicted by a nonlinear QCD evolution equation may greatly enhance the cross sections of proton-target interactions and give rise to a characteristic broken power law in the gamma-ray spectra. The result is used to explore the gluon condensation signature in the observed gamma-ray spectra from pulsars.

    ↳ astro-ph.HEhep-phJCAP(2021)·8 citations
29. 29*

    The Crucial Calculation as a Motivating Force In Particle Physics

    Howard J. Schnitzer🇺🇸

    Crucial experiments have a long history of contributions to progress in physics. Similarly, we claim that in the period roughly from 1955 to 1985 crucial calculations played a significant role in setting the agenda for elementary particle physics. The highlights of the contributions of theoretical physics to the achievement of the standard model is emphasized

    ↳ physics.hist-phhep-phhep-th1 citation
30. 30*

    Tests of Fundamental Quantum Mechanics and Dark Interactions with Low Energy Neutrons -- Extended Version

    Stephan Sponar🇦🇹 · Rene I.P. Sedmik🇦🇹 · Mario Pitschmann🇦🇹 · Hartmut Abele🇦🇹 · Yuji Hasegawa🇦🇹

    Among the known particles, the neutron takes a special position, as it provides experimental access to all four fundamental forces and a wide range of hypothetical interactions. Despite being unstable, free neutrons live long enough to be used as test particles in interferometric, spectroscopic, and scattering experiments probing low-energy scales. As was already recognized in the 1970s, fundamental concepts of quantum mechanics can be tested in neutron interferometry using silicon perfect-single-crystals. Besides allowing for tests of uncertainty relations, Bell inequalities and alike, neutrons offer the opportunity to observe the effects of gravity and hypothetical dark forces acting on extended matter wave functions. Such tests gain importance in the light of recent discoveries of inconsistencies in our understanding of cosmology as well as the incompatibility between quantum mechanics and general relativity. Experiments with low-energy neutrons are thus indispensable tools for probing fundamental physics and represent a complementary approach to colliders. In this review we discuss the history and experimental methods used at this low-energy frontier of physics and collect bounds and limits on quantum mechanical relations and dark energy interactions.

    ↳ quant-phhep-phNature Rev.Phys.(2021)·45 citations
31. 31*

    Nonlinear curvature effects in gravitational waves from inspiralling black hole binaries

    Banafsheh Shiralilou🇳🇱 · Tanja Hinderer🇳🇱 · Samaya Nissanke🇳🇱 · Néstor Ortiz🇲🇽 · Helvi Witek🇺🇸

    Gravitational waves (GWs) from merging black holes allow for unprecedented probes of strong-field gravity. Testing gravity in this regime requires accurate predictions of gravitational waveform templates in viable extensions of General Relativity. We concentrate on scalar Gauss-Bonnet gravity, one of the most compelling classes of theories appearing as low-energy limit of quantum gravity paradigms, which introduces quadratic curvature corrections to gravity coupled to a scalar field and allows for black hole solutions with scalar-charge. Focusing on inspiralling black hole binaries, we compute the leading-order corrections due to curvature nonlinearities in the GW and scalar waveforms, showing that the new contributions, beyond merely the effect of scalar field, appear at first post-Newtonian order in GWs. We provide ready-to-implement GW polarizations and phasing. Computing the GW phasing in the Fourier domain, we perform a parameter-space study to quantify the detectability of deviations from General Relativity. Our results lay important foundations for future precision tests of gravity with both parametrized and theory-specific searches.

    ↳ gr-qcastro-ph.HEhep-phhep-thPRD(2021)·64 citations
32. 32*

    Searching for axion-like particle decay in the near-infrared background: an updated analysis

    Andrea Caputo🇮🇱 · Andrea Vittino🇩🇪 · Nicolao Fornengo🇮🇹 · Marco Regis🇮🇹 · Marco Taoso🇮🇹

    The extragalactic background light is comprised of the cumulative radiation from all galaxies across the history of the universe. The angular power spectrum of the anisotropies of such a background at near-infrared (IR) frequencies lacks of a complete understanding and shows a robust excess which cannot be easily explained with known sources. Dark matter in the form of axion-like particles (ALPs) with a mass around the electronvolt will decay into two photons with wavelengths in the near-IR band, possibly contributing to the background intensity. We compute the near-IR background angular power spectrum including emissions from galaxies, as well as the contributions from the intra-halo light and ALP decay, and compare it to measurements from the Hubble Space Telescope and Spitzer. We find that the preferred values for the ALP mass and ALP-photon coupling to explain the excess are in tension with star cooling data and observations of dwarf spheroidal galaxies.

    ↳ astro-ph.COhep-phJCAP(2021)·28 citations
33. 33*

    Statistical coupling constants from hidden sector entanglement

    Vijay Balasubramanian🇧🇪 · Jonathan J. Heckman🇺🇸 · Elliot Lipeles🇺🇸 · Andrew P. Turner🇺🇸

    String theory predicts that the couplings of Nature descend from dynamical fields. All known string-motivated particle physics models also come with a wide range of possible extra sectors. It is common to posit that such moduli are frozen to a background value, and that extra sectors can be nearly completely decoupled. Performing a partial trace over all sectors other than the visible sector generically puts the visible sector in a mixed state, with coupling constants drawn from a quantum statistical ensemble. An observable consequence of this entanglement between visible and extra sectors is that the reported values of couplings will appear to have an irreducible variance. Including this variance in fits to experimental data gives an important additional parameter that can be used to distinguish this scenario from the case where couplings are treated as fixed parameters. There is a consequent interplay between energy range and precision of an experiment that allows an extended reach for new physics.

    ↳ hep-thhep-exhep-phPRD(2021)·17 citations
34. 34*

    Troubles with Global Monopoles in Quantum Gravity

    Nemanja Kaloper🇺🇸

    A theory with a global $O(3)$ symmetry broken at a scale $\eta$ admits topological configurations: global monopoles realized by Goldstone fields winding around the core of false vacuum. One may expect them to behave as heavy, big composite objects, difficult to make and therefore mostly harmless. However, after gravity is turned on, as long as Equivalence Principle holds, one finds that global monopoles have a negative mass, $M\sim -\eta /\sqrt{\lambda }$, where $\lambda$ is the field theory coupling. This could catalyze an instability in the space of a global monopole, by the production of additional global monopole-antimonopole pairs along with normal particles, leading to energy production {\it ab nihilo}, if the pair energy is dominated by their negative rest masses. In a theory with unbroken local Poincaré symmetry, this could lead to a divergent `decay rate' of the global monopole configurations.

    ↳ hep-thastro-ph.COgr-qchep-phInt.J.Mod.Phys.D(2022)·1 citation
35. 35*

    Localized brane-world black hole analytically connected to an AdS${}_5$ boundary

    Theodoros Nakas🇬🇷 · Panagiota Kanti🇬🇷

    We construct from first principles the geometry of an analytic, exponentially localized five-dimensional brane-world black hole. The black-hole singularity lies entirely on the 3-brane, while the event horizon is shown to have a pancake shape. The induced line-element on the brane assumes the form of the Schwarzschild solution while the bulk geometry is effectively AdS${}_5$ outside the horizon. The derived geometry is supported by an anisotropic fluid in the bulk described only by two independent components, the energy density and tangential pressure, whereas no matter needs to be introduced on the brane for its consistent embedding in the bulk.

    ↳ hep-thgr-qchep-phPLB(2021)·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.