Fri·Nov 20, 2020Friday·November 20, 2020

1. 01*

   A warped scalar portal to fermionic dark matter

   Adrian Carmona🇪🇸 · Javier Castellano Ruiz🇩🇪 · Matthias Neubert🇩🇪

   We argue that extensions of the SM with a warped extra dimension, together with a new ${\mathbb{Z}}_2$-odd scalar singlet, provide a natural explanation not only for the hierarchy problem but also for the nature of fermion bulk masses and the observed dark matter relic abundance. In particular, the Kaluza-Klein excitations of the new scalar particle, which is required to naturally obtain fermion bulk masses through Yukawa-like interactions, can be the leading portal to any fermion propagating into the bulk of the extra dimension and playing the role of dark matter. Moreover, such scalar excitations will necessarily mix with the Higgs boson, leading to modifications of the Higgs couplings and branching ratios, and allowing the Higgs to mediate the coannihilation of the fermionic dark matter. We study these effects and explore the viability of fermionic dark matter in the presence of these new heavy scalar mediators both in the usual freeze-out scenario and in the case where the freeze-out happens during an early period of matter domination.

   hep-phEPJC(2021)·14 citations
2. 02*

   The Migdal effect in semiconductors

   Simon Knapen🇨🇭 · Jonathan Kozaczuk🇺🇸 · Tongyan Lin🇺🇸

   When a nucleus in an atom undergoes a collision, there is a small probability to inelastically excite an electron as a result of the Migdal effect. In this Letter, we present a first complete derivation of the Migdal effect from dark matter-nucleus scattering in semiconductors, which also accounts for multiphonon production. The rate can be expressed in terms of the energy loss function of the material, which we calculate with density functional theory (DFT) methods. Because of the smaller gap for electron excitations, we find that the rate for the Migdal effect is much higher in semiconductors than in atomic targets. Accounting for the Migdal effect in semiconductors can therefore significantly improve the sensitivity of experiments such as DAMIC, SENSEI and SuperCDMS to sub-GeV dark matter.

   hep-phhep-exPRL(2021)·116 citations
3. 03*

   Correlation between multiple scattering angle and ionization energy loss for fast electrons

   M.V. Bondarenco🇺🇦

   A correlation between the angle of multiple scattering and the ionization energy loss for relativistic electrons in an amorphous medium is computed by solving the combined transport equation. The correlation is found to be the most pronounced at deflection angles larger than typical, reflecting the underlying single-scattering kinematical correlation, but is also sizable at typical deflection angles, where the width of the angular distribution increases with the increase of the energy loss. The mean energy loss as a function of the deflection angle is calculated. It grows quadratically both at small and at large angles, but the proportionality coefficient at large angles is greater than at small ones.

   hep-phhep-exphysics.acc-phPRD(2021)·1 citation
4. 04*

   Leading neutron production at the EIC and LHeC: estimating the impact of the absorptive corrections

   F. Carvalho🇧🇷 · V.P. Gonçalves🇧🇷 · F.S. Navarra🇧🇷 · D. Spiering🇧🇷

   Leading neutron (LN) production in $ep$ collisions at high energies is investigated using the color dipole formalism and taking into account saturation effects. We update the treatment of absorptive effects and estimate the impact of these effects on LN spectra in the kinematical range that will be probed by the Electron Ion Collider (EIC) and by the Large Hadron electron Collider (LHeC). We demonstrate that Feynman scaling, associated to saturation, is not violated by the inclusion of absorptive effects. Moreover, our results indicate that the LN spectrum is strongly suppressed at small photon virtualities. These results suggest that absorptive effects cannot be disregarded in future measurements of the $\gamma \pi$ cross section to be extracted from data on leading neutron production.

   hep-phPRD(2021)·8 citations
5. 05*

   Light quark Yukawas in triboson final states

   Adam Falkowski🇫🇷 · Sanmay Ganguly🇮🇱 · Phillippe Gras🇫🇷 · Jose Miguel No🇪🇸 · Kohsaku Tobioka🇺🇸 · Natascia Vignaroli🇮🇹 · Tevong You🇨🇭

   Triple heavy vector boson production, $pp\to VVV$ $(V=W,Z)$, has recently been observed for the first time. We propose that precision measurements of this process provide an excellent probe of the first generation light quark Yukawa couplings. Modified quark interactions with the off-shell Higgs in this process lead to a rapid growth of the partonic cross sections with energy, which manifests in an enhanced $p_T$ distribution of the final state leptons and quarks. We quantify this effect and estimate the present and future 2$\sigma$ sensitivity to the up, down, and strange Yukawas. In particular, we find that HL-LHC can reach $\mathcal{O}(400)$ sensitivity to the down Yukawa relative to the Standard Model value, improving the current sensitivity in this process by a factor of $10$, and which can be further improved to $\mathcal{O}(30)$ at FCC-hh. This is competitive with and complementary to constraints from global fits and other on-shell probes of the first generation Yukawas. The triboson sensitivity at HL-LHC corresponds to probing dimension-6 SMEFT operators suppressed by an $\mathcal{O}(1)$ TeV scale, similarly to other LHC Higgs probes.

   hep-phhep-exJHEP(2021)·37 citations
6. 06*

   Two and Three Pseudoscalar Production in $e^{+}{e}^{-}$ annihilation and their contributions to $(g-2{)}_{\mu }$

   Wen Qin🇨🇳 · Ling-Yun Dai🇨🇳 · Jorge Portoles🇪🇸

   A coherent study of $e^{+}{e}^{-}$ annihilation into two (${\pi }^{+}{\pi }^{-}$,$K^{+}{K}^{-}$) and three (${\pi }^{+}{\pi }^{-}{\pi }^0,{\pi }^{+}{\pi }^{-}\eta$) pseudoscalar meson production is carried out within the framework of resonance chiral theory in energy region $E\lesssim 2\mathrm{GeV}$. The work of {[}L. Y. Dai, J. Portolés, and O. Shekhovtsova, Phys. Rev. D 88,056001 (2013){]} is revisited with the latest experimental data and a joint analysis of two pseudoscalar meson production. Hence, we evaluate the lowest order hadronic vacuum polarization contributions of those two and three pseudoscalar processes to the anomalous magnetic moment of the muon. We also estimate some higher-order additions led by the same hadronic vacuum polarization. Combined with the other contributions from the standard model, the theoretical prediction differs still by $(21.6\pm 7.4)\times 10^{-10}$ (2.9$\sigma$) from the experimental value.

   hep-phhep-exJHEP(2021)·29 citations
7. 07*

   Mixing Angle of ${\Xi }_Q-{\Xi }_Q^{\prime }$ in Heavy Quark Effective Therory

   Yoshimitsu Matsui🇯🇵

   The Heavy Quark Effective Theory provides a systematic method to estimate a mixing angle of hadron states in a heavy quark, such as the charm quark (c) and the bottom quark (b). By using this method, the mixing angle of the baryons ${\Xi }_Q-{\Xi }_Q^{\prime }$ can be estimated. It is found that the mixing angle between ${\Xi }_Q$ and ${\Xi }_Q^{\prime }$ is given by ${\theta }_b=4.51^{\circ }\pm 0.79^{\circ }$ for $Q=b$ case and ${\theta }_c=8.12^{\circ }\pm 0.80^{\circ }$ for $Q=c$ case.

   hep-phnucl-thNPA(2021)·8 citations
8. 08*

   On the reactions involving neutrinos and hidden mass particles in hypercolor model

   Vitaly Beylin🇷🇺 · Vladimir Kuksa🇷🇺

   We present and discuss some basic elements of the Standard Model hypercolor extension. Appearance of a set of hyperquarks bound states is resulted from $\sigma -$model using; due to specific symmetries of this minimal extension, there arise stable hypermesons and hyperbaryons which are interpreted as the Dark Matter candidates. Knowing estimations of their masses from analysis of Dark Matter annihilation kinetics, some processes of high energy cosmic rays scattering off these particles are analyzed for the search of Dark Matter manifestations.

   hep-ph0 citations
9. 09*

   Tetra-quarks, penta-quarks and the like: old and new views

   Giancarlo Rossi🇮🇹 · Gabriele Veneziano🇨🇭

   In this talk, after a short overview of the history of the discovery of tetra-quarks and penta-quarks, we will discuss a possible interpretation of such states in the framework of a 40-years-old "string junction" picture that allows a unified QCD description of ordinary mesons and baryons as well as multi-quark resonances.

   hep-phNucl.Part.Phys.Proc.(2021)·8 citations
10. 10*

    Non-local matrix elements in $B_{(s)}\to \{K^{(\ast )},\varphi \}{\ell }^{+}{\ell }^{-}$

    Nico Gubernari🇩🇪 · Danny van Dyk🇩🇪 · Javier Virto🇪🇸

    We revisit the theoretical predictions and the parametrization of non-local matrix elements in rare ${\bar{B}}_{(s)}\to \{{\bar{K}}^{(\ast )},\varphi \}{\ell }^{+}{\ell }^{-}$ and ${\bar{B}}_{(s)}\to \{{\bar{K}}^{\ast },\varphi \}\gamma$ decays. We improve upon the current state of these matrix elements in two ways. First, we recalculate the hadronic matrix elements needed at subleading power in the light-cone OPE using $B$-meson light-cone sum rules. Our analytical results supersede those in the literature. We discuss the origin of our improvements and provide numerical results for the processes under consideration. Second, we derive the first dispersive bound on the non-local matrix elements. It provides a parametric handle on the truncation error in extrapolations of the matrix elements to large timelike momentum transfer using the $z$ expansion. We illustrate the power of the dispersive bound at the hand of a simple phenomenological application. As a side result of our work, we also provide numerical results for the $B_s\to \varphi$ form factors from $B$-meson light-cone sum rules.

    hep-phhep-exJHEP(2021)·181 citations
11. 11*

    Non-Abelian Alice strings in two-flavor dense QCD

    Yuki Fujimoto🇯🇵 · Muneto Nitta🇯🇵

    Quark-hadron continuity with two-flavor quarks that was proposed recently connects hadronic matter with neutron ${}^3{P}_2$ superfluidity and two-flavor dense quark matter. This two-flavor dense quark phase consists of the coexistence of the 2SC condensates and the $P$-wave diquark condensates of $d$-quarks, which gives rise to color superconductivity as well as superfluidity. We classify vortices in this phase. The most stable vortices are what we call the non-Abelian Alice strings, which are superfluid vortices with non-Abelian color magnetic fluxes therein, exhibiting so-called topological obstruction, or a non-Abelian generalization of the Alice property. We show that a single Abelian superfluid vortex is unstable against decay into three non-Abelian Alice strings. We discover that a non-Abelian Alice string carries orientational moduli of the real projective space $\mathbb{R}{P}^2$ corresponding to the color flux therein in the presence of the $P$-wave condensates alone. We calculate Aharanov-Bohm (AB) phases around the non-Abelian Alice string, and find that the 2SC condensates and string's orientational moduli must be aligned with each other because of single-valuedness of the AB phases of the 2SC condensates.

    hep-phastro-ph.HEcond-mat.supr-conhep-th+1PRD(2021)·17 citations
12. 12*

    Gauge anomalies in the Standard-Model Effective Field Theory

    Oscar Cata🇩🇪 · Wolfgang Kilian🇩🇪 · Nils Kreher🇩🇪

    If the Standard Model is understood as the first term of an effective field theory, the anomaly-cancellation conditions have to be worked out and fulfilled order by order in the effective field-theory expansion. We bring attention to this issue and study in detail a subset of the anomalies of the effective field theories at the electroweak scale. The end result is a set of sum rules for the operator coefficients. These conditions, which are necessary for the internal consistency of the theory, lead to a number of phenomenological consequences when implemented in analyses of experimental data. In particular, they not only decrease the number of free parameters in different physical processes but have the potential to relate processes with different flavor content. Conversely, a violation of these conditions would necessarily imply the existence of undetected non-decoupling new physics associated with the electroweak energy scale.

    hep-ph14 citations
13. 13*

    The Anomalous Case of Axion EFTs and Massive Chiral Gauge Fields

    Quentin Bonnefoy🇩🇪 · Luca Di Luzio🇩🇪 · Christophe Grojean🇩🇪 · Ayan Paul🇩🇪 · Alejo N. Rossia🇩🇪

    We study axion effective field theories (EFTs), with a focus on axion couplings to massive chiral gauge fields. We investigate the EFT interactions that participate in processes with an axion and two gauge bosons, and we show that, when massive chiral gauge fields are present, such interactions do not entirely originate from the usual anomalous EFT terms. We illustrate this both at the EFT level and by matching to UV-complete theories. In order to assess the consistency of the Peccei--Quinn (PQ) anomaly matching, it is useful to introduce an auxiliary, non-dynamical gauge field associated to the PQ symmetry. When applied to the case of the Standard Model (SM) electroweak sector, our results imply that anomaly-based sum rules between EFT interactions are violated when chiral matter is integrated out, which constitutes a smoking gun of the latter. As an illustration, we study a UV-complete chiral extension of the SM, containing an axion arising from an extended Higgs sector and heavy fermionic matter that obtains most of its mass by coupling to the Higgs doublets. We assess the viability of such a SM extension through electroweak precision tests, bounds on Higgs rates and direct searches for heavy charged matter. At energies below the mass of the new chiral fermions, the model matches onto an EFT where the electroweak gauge symmetry is non-linearly realised.

    hep-phhep-thJHEP(2021)·31 citations
14. 14*

    Colour and logarithmic accuracy in final-state parton showers

    Keith Hamilton🇬🇧 · Rok Medves🇬🇧 · Gavin P. Salam🇬🇧 · Ludovic Scyboz🇬🇧 · Gregory Soyez🇫🇷

    Standard dipole parton showers are known to yield incorrect subleading-colour contributions to the leading (double) logarithmic terms for a variety of observables. In this work, concentrating on final-state showers, we present two simple, computationally efficient prescriptions to correct this problem, exploiting a Lund-diagram type classification of emission regions. We study the resulting effective multiple-emission matrix elements generated by the shower, and discuss their impact on subleading colour contributions to leading and next-to-leading logarithms (NLL) for a range of observables. In particular we show that the new schemes give the correct full colour NLL terms for global observables and multiplicities. Subleading colour issues remain at NLL (single logarithms) for non-global observables, though one of our two schemes reproduces the correct full-colour matrix-element for any number of energy-ordered commensurate-angle pairs of emissions. While we carry out our tests within the PanScales shower framework, the schemes are sufficiently simple that it should be straightforward to implement them also in other shower frameworks.

    hep-phJHEP(2021)·122 citations
15. 15*

    Causality, Unitarity and Symmetry in Effective Field Theory

    Timothy Trott🇺🇸

    Sum rules in effective field theories, predicated upon causality, place restrictions on scattering amplitudes mediated by effective contact interactions. Through unitarity of the $S$-matrix, these imply that the size of higher dimensional corrections to transition amplitudes between different states is bounded by the strength of their contributions to elastic forward scattering processes. This places fundamental limits on the extent to which hypothetical symmetries can be broken by effective interactions. All analysis is for dimension $8$ operators in the forward limit. Included is a thorough derivation of all positivity bounds for a chiral fermion in $SU(2)$ and $SU(3)$ global symmetry representations resembling those of the Standard Model, general bounds on flavour violation, new bounds for interactions between particles of different spin, inclusion of loops of dimension $6$ operators and illustration of the resulting strengthening of positivity bounds over tree-level expectations, a catalogue of supersymmetric effective interactions up to mass dimension $8$ and $4$ legs and the demonstration that supersymmetry unifies the positivity theorems as well as the new bounds.

    hep-phhep-thJHEP(2021)·66 citations
16. 16*

    A model for the Singlet-Triplet Leptoquarks

    Leandro Da Rold (Centro Atómico Bariloche, Instituto Balseiro and CONICET)🇦🇷 · Federico Lamagna (Centro Atómico Bariloche, Instituto Balseiro and CONICET)🇦🇷

    The deviations of $B$-meson decays measured in $R_{D^{(\ast )}}^{\tau \ell }$ and $R_{K^{(\ast )}}^{\mu e}$ can be explained by the presence of two scalar leptoquarks, a singlet $S_1$ and a triplet $S_3$, mostly coupled to the third generation. We consider a theory of resonances, as an effective description of a strongly interacting theory, that generates the leptoquarks and the Higgs as Nambu-Goldstone bosons, with the rest of the resonances at a scale of order $10-30\mathrm{TeV}$. We assume anarchic partial compositeness for the flavor of the SM fermions. Under these hypothesis we study whether it is possible to reproduce the deviations in the $B$-decays without being in conflict with flavor and electroweak bounds. We find a tension between $R_{D^{(\ast )}}^{\tau \ell }$ and some flavor observables, dominated by flavor violating $\tau$ decays and $\Delta m_{B_s}$, that require a tuning of order $10-25\%$. We also compute the potential of the scalars showing that leptoquarks with masses $O(2-3)\mathrm{TeV}$ can be naturally expected in the model. We discuss briefly the phenomenology of the other resonances.

    hep-phhep-exPRD(2021)·18 citations
17. 17*

    Charged current semi-inclusive deeply inelastic scattering at the Electron-Ion Collider

    Weihua Yang🇨🇳

    We present a systematic calculation of the charged current semi-inclusive deeply inelastic scattering process at leading order twist-3 level in the parton model. We consider the general form of the negatively charged beam scattering off the polarized target which has spin-1. The calculations are carried out by applying the collinear expansion where multiple gluon scattering is taken into account and gauge links are obtained automatically. We first present the general form of the differential cross section in terms of the structure functions by kinematic analysis and then present the structure functions in terms of the the gauge invariant parton distribution functions up to twist-3 level. Considering the angle modulations and polarizations of the cross section, we calculate the complete azimuthal asymmetries in the charged current semi-inclusive deeply inelastic scattering process. The charge asymmetries are also considered in this paper with the introduction of the definitions of the $plus$ and $minus$ cross sections.

    hep-phPRD(2021)·13 citations
18. 18*

    Modifying PyUltraLight to model scalar dark matter with self-interactions

    Noah Glennon🇺🇸 · Chanda Prescod-Weinstein🇺🇸

    We introduce a modification of the PyUltraLight code that models the dynamical evolution of ultralight axionlike scalar dark matter fields. Our modified code, PySiUltraLight, adds a quartic, self-interaction term to reflect the one which arises naturally in axionlike particle models. Using a particle mass of $10^{-22}\mathrm{eV}/{\mathrm{c}}^2$, we show that PySiUltraLight produces spatially oscillating solitons, exploding solitons, and collapsing solitons which prior analytic work shows will occur with attractive self-interactions. Using our code we calculate the oscillation frequency as a function of soliton mass and equilibrium radius in the presence of attractive self-interactions. We show that when the soliton mass is below the critical mass ($M_c=\frac{\sqrt{3}}{2}{M}_{\max }$) described by Chavanis [arxiv:1604.05904] and the initial radius is within a specific range, solitons are unstable and explode. We test the maximum mass criteria described by Chavanis [arxiv:1604.05904] and Chavanis and Delfini [arxiv:1103.2054] for a soliton to collapse when attractive self-interactions are included. We also analyze both binary soliton collisions and a soliton rotating around a central mass with attractive and repulsive self-interactions. We find that when attractive self-interactions are included, the density profiles get distorted after a binary collision. We also find that a soliton is less susceptible to tidal stripping when attractive self-interactions are included. We find that the opposite is true for repulsive self-interactions in that solitons would be more easily tidally stripped. Including self-interactions might therefore influence the survival timescales of infalling solitons.

    ↳ astro-ph.COhep-phPRD(2021)·44 citations
19. 19*

    Axions, Higher-Groups, and Emergent Symmetry

    T. Daniel Brennan🇺🇸 · Clay Cordova🇺🇸

    Axions, periodic scalar fields coupled to gauge fields through the instanton density, have a rich variety of higher-form global symmetries. These include a two-form global symmetry, which measures the charge of axion strings. As we review, these symmetries typically combine into a higher-group, a kind of non-abelian structure where symmetries that act on operators of different dimensions, such as points, lines, and strings, are mixed. We use this structure to derive model independent constraints on renormalization group flows that realize theories of axions at long distances. These give universal inequalities on the energy scales where various infrared symmetries emerge. For example, we show that in any UV completion of axion-Yang-Mills, the energy scale at which axion strings can decay is always larger than the mass scale of charged particles.

    ↳ hep-thhep-phJHEP(2022)·105 citations
20. 20*

    Three-flavor collective neutrino conversions with multi-azimuthal-angle instability in an electron-capture supernova model

    Masamichi Zaizen🇯🇵 · Shunsaku Horiuchi🇺🇸 · Tomoya Takiwaki🇯🇵 · Kei Kotake🇯🇵 · Takashi Yoshida🇯🇵 · Hideyuki Umeda🇯🇵 · John F. Cherry🇺🇸

    We investigate the multi-azimuthal angle (MAA) effect on collective neutrino oscillation by considering the three-dimensional neutrino momentum distribution in a realistic electron-capture supernova model with an $8.8M_{\odot }$ progenitor. We find that the MAA effect induces collective flavor conversions at epochs when it is completely suppressed under the axial-symmetric approximation. This novel activity is switched on/off by the growth of the MAA instability and imprints additional time evolution in the expected neutrino event rate. We validate our results by extending the linear stability analysis into the three-flavor scheme including mixing angles, and confirm that the onset of collective neutrino oscillation matches the steep growth of flavor instability. We discuss how the MAA effect alters neutrino detection at Super-Kamiokande and DUNE.

    ↳ astro-ph.HEhep-phPRD(2021)·13 citations
21. 21*

    Generalised velocity-dependent one-scale model for current-carrying strings

    C. J. A. P. Martins🇵🇹 · Patrick Peter🇫🇷 · I. Yu. Rybak🇵🇹 · E. P. S. Shellard🇬🇧

    We develop an analytic model to quantitatively describe the evolution of superconducting cosmic string networks. Specifically, we extend the velocity-dependent one-scale (VOS) model to incorporate arbitrary currents and charges on cosmic string worldsheets under two main assumptions, the validity of which we also discuss. We derive equations that describe the string network evolution in terms of four macroscopic parameters: the mean string separation (or alternatively the string correlation length) and the root mean square (RMS) velocity which are the cornerstones of the VOS model, together with parameters describing the averaged timelike and spacelike current contributions. We show that our extended description reproduces the particular cases of wiggly and chiral cosmic strings, previously studied in the literature. This VOS model enables investigation of the evolution and possible observational signatures of superconducting cosmic string networks for more general equations of state, and these opportunities will be exploited in a companion paper.

    ↳ astro-ph.COhep-phPRD(2021)·29 citations
22. 22*

    $(\mathcal{F},\mathcal{G})$-summed form of the QED effective action

    Jose Navarro-Salas🇪🇸 · Silvia Pla🇪🇸

    We conjecture that the proper-time series expansion of the one-loop effective Lagrangian of quantum electrodynamics can be summed in all terms containing the field-strength invariants $\mathcal{F}=\frac{1}{4}{F}_{\mu \nu }{F}^{\mu \nu }(x)$, $\mathcal{G}=\frac{1}{4}{\tilde{F}}_{\mu \nu }{F}^{\mu \nu }(x)$, including those also possessing derivatives of the electromagnetic field strength. This partial resummation is exactly encapsulated in a factor with the same form as the Heisenberg-Euler Lagrangian density, except that now the electric and magnetic fields can depend arbitrarily on spacetime coordinates. We provide strong evidence for this conjecture, which is proved to sixth order in the proper time. Furthermore, and as a byproduct, we generate some solvable electromagnetic backgrounds. We also discuss the implications for a generalization of the Schwinger formula for pair production induced by nonconstant electric fields. Finally, we briefly outline the extension of these results in the presence of gravity.

    ↳ hep-thgr-qchep-phPRD(2021)·14 citations
23. 23*

    Distribution Amplitudes of $K^{\ast }$ and $\varphi$ at Physical Pion Mass from Lattice QCD

    Jun Hua🇨🇳 · Min-Huan Chu🇨🇳 · Peng Sun🇨🇳 · Wei Wang🇨🇳 · Ji Xu🇨🇳 · Yi-Bo Yang🇨🇳 · Jian-Hui Zhang🇨🇳 · Qi-An Zhang🇨🇳

    We present the first lattice QCD calculation of the distribution amplitudes of longitudinally and transversely polarized vector mesons $K^{\ast }$ and $\varphi$ using large momentum effective theory. We use the clover fermion action on three ensembles with 2+1+1 flavors of highly improved staggered quarks (HISQ) action, generated by MILC collaboration, at physical pion mass and \{0.06, 0.09, 0.12\} fm lattice spacings, and choose three different hadron momenta $P_z=\{1.29,1.72,2.15\}$ GeV. The resulting lattice matrix elements are nonperturbatively renormalized in a hybrid scheme proposed recently. An extrapolation to the continuum and infinite momentum limit is carried out. We find that while the longitudinal distribution amplitudes tend to be close to the asymptotic form, the transverse ones deviate rather significantly from the asymptotic form. Our final results provide crucial {\it ab initio} theory inputs for analyzing pertinent exclusive processes.

    ↳ hep-lathep-phPRL(2021)·84 citations
24. 24*

    Universal Peaks Ratio In The Spectral Energy Density Of Double Hump Blazars, Gamma Ray Bursts, And Microquasars

    Shlomo Dado🇮🇱 · Arnon Dar🇮🇱

    The peak frequencies of the two broad humps evident in the spectral energy density of blazars (SED) are time dependent and vary a lot between different blazars. However, their ratio in most blazars, appears to be almost universal and equal to $m_e{c}^2/4(1+z){ϵ}_p$ to a good approximation, where $m_e$ is the electron mass, ${ϵ}_p$ is the peak energy of the cosmic microwave background radiation, and $z$ is the redshift of the blazar. We discuss a possible origin of such a universal ratio in blazars and gamma ray bursts (GRBs). We point out a possible connection between the knee in the energy spectrum of cosmic ray electrons and the maximal peak energies of the two broad humps in the SED of high-energy peaked blazars.

    ↳ astro-ph.HEhep-phApJL(2021)·1 citation
25. 25*

    Machine learning approach for the search of resonances with topological features at the Large Hadron Collider

    Salah-eddine Dahbi🇿🇦 · Joshua Choma🇿🇦 · Bruce Mellado🇿🇦 · Gaogalalwe Mokgatitswane🇿🇦 · Xifeng Ruan🇿🇦 · Benjamin Lieberman🇿🇦 · Turgay Celik🇿🇦

    The observation of resonances is unequivocal evidence of new physics beyond the Standard Model at the Large Hadron Collider (LHC). So far, inclusive and model dependent searches have not provided evidence of new resonances, indicating that these could be driven by subtle topologies. Here, we use machine learning techniques based on weak supervision to perform searches. Weak supervision based on mixed samples can be used to search for resonances with little or no prior knowledge on the production mechanism. Also, it offers the advantage that sidebands or control regions can be used to effectively model backgrounds with minimal reliance on simulations. However, weak supervision alone is found to be highly inefficient in identifying corners of the multi-dimensional space of interest. Instead, we propose an approach to search for new resonances that involves a classification procedure that is signature and topology based. A combination of weak supervision with Deep Neural Network algorithms are applied following this classification. The performance of this strategy is evaluated on the production of SM Higgs boson decaying to a pair of photons inclusively and in exclusive regions of phase space tailored for specific production modes at the LHC. After verifying the ability of the methodology to extract different SM Higgs boson signal mechanisms, a search for new phenomena in high-mass final states is setup for the LHC.

    ↳ hep-exhep-phInt.J.Mod.Phys.A(2022)·8 citations
26. 26*

    Neutrino-Assisted Early Dark Energy: Theory and Cosmology

    Mariana Carrillo González🇬🇧 · Qiuyue Liang🇺🇸 · Jeremy Sakstein🇺🇸 · Mark Trodden🇺🇸

    The tension between measurements of the Hubble constant obtained at different redshifts may provide a hint of new physics active in the relatively early universe, around the epoch of matter-radiation equality. A leading paradigm to resolve the tension is a period of early dark energy, in which a scalar field contributes a subdominant part of the energy budget of the universe at this time. This scenario faces significant fine-tuning problems which can be ameliorated by a non-trivial coupling of the scalar to the standard model neutrinos. These become non-relativistic close to the time of matter-radiation equality, resulting in an energy injection into the scalar that kick-starts the early dark energy phase, explaining its coincidence with this seemingly unrelated epoch. We present a minimal version of this neutrino-assisted early dark energy model, and perform a detailed analysis of its predictions and theoretical constraints. We consider both particle physics constraints -- that the model constitute a well-behaved effective field theory for which the quantum corrections are under control, so that the relevant predictions are within its regime of validity -- and the constraints provided by requiring a consistent cosmological evolution from early through to late times. Our work paves the way for testing this scenario using cosmological data sets.

    ↳ astro-ph.COhep-phJCAP(2021)·71 citations
27. 27*

    A new way to test the WIMP dark matter models

    Wei Cheng🇨🇳 · Yuan He🇨🇳 · Jin-Wang Diao🇨🇳 · Yu Pan🇨🇳 · Jun Zeng🇨🇳 · Jia-Wei Zhang🇨🇳

    In this paper, we investigate the possibility of testing the weakly interacting massive particle (WIMP) dark matter (DM) models by applying the simplest phenomenological model which introduces an interaction term between dark energy (DE) and WIMP DM, i.e., $Q=3{\gamma }_{DM}H{\rho }_{DM}$. In general, the coupling strength ${\gamma }_{DE}$ is close to $0$ as the interaction between DE and WIMP DM is very weak, thus the effect of ${\gamma }_{DE}$ on the evolution of $Y$ associated with DM energy density can be safely neglected. Meanwhile, our numerical calculation also indicates that $x_f\approx 20$ is associated with DM freeze-out temperature, which is the same as the vanishing interaction scenario. As for DM relic density, it will be magnified by $\frac{2-3{\gamma }_{DM}}{2}[2\pi g_{\ast }{m}_{DM}^3/(45s_0{x}_f^3){]}^{{\gamma }_{DM}}$ times, which provides a new way to test WIMP DM models. As an example, we analyze the case in which WIMP DM is a scalar DM. (SGL+SNe+Hz) and (CMB+BAO+SNe) cosmological observations will give ${\gamma }_{DM}=0.134_{-0.069}^{+0.17}$ and ${\gamma }_{DM}=-0.0008\pm 0.0016$, respectively. After further considering the constraints from DM direct detection experiment, DM indirect detection experiment, and DM relic density, we find that the allowed parameter space of the scalar DM model will be completely excluded for the former cosmological observations, while it will increase for the latter ones. Those two cosmological observations lead to an almost paradoxical conclusion. Therefore, one could expect more stringent constraints on the WMIP DM models, with the accumulation of more accurate cosmological observations in the near future.

    ↳ astro-ph.COhep-phhep-thJHEP(2021)·5 citations

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