Thu·Nov 5, 2020Thursday·November 5, 2020

1. 01*

   Probing Heavy Charged Higgs Bosons through Bottom Flavored Hadrons in the $H^{+}\to \bar{b}t\to B+X$ Channel in 2HDM

   S. Mohammad Moosavi Nejad🇮🇷 · P. Sartipi Yarahmadi🇮🇷

   Observing light or heavy charged Higgs bosons $H^{\pm }$, lighter or heavier than the top quark, would be instant evidence of physics beyond the Standard Model. For this reason, in recent years searches for charged Higgs bosons have been in the center of attention of current colliders such as the CERN Large Hadron Collider (LHC). In spite of all efforts, no signal has been yet observed. Especially, the results of CMS and ATLAS experiments have excluded a large region in the MSSM $m_{H^{+}}-\tan \beta$ parameter space for $m_{H^{+}}=80-160$ GeV corresponding to the entire range of $\tan \beta$ up to 60. Therefore, it seems that one should concentrate on probing heavy charged Higgs bosons ($m_{H^{\pm }}>m_t$) so in this context each new probing channel is welcomed. In this work, we intend to present our proposed channel to search for heavy charged Higgses through the study of scaled-energy distribution of bottom-flavored mesons ($B$) inclusively produced in charged Higgs decay, i.e., $H^{+}\to t\bar{b}\to B+X$. Our study is carried out within the framework of the generic two Higgs doublet model (2HDM) using the massless scheme where the zero mass parton approximation is adopted for bottom quark.

   hep-phEPJC(2021)·1 citation
2. 02*

   Refined Mass Estimate for Bilepton Gauge Boson

   Claudio Corianò🇮🇹 · Paul H. Frampton🇮🇹

   Using the most recent experimental data on parameters of the standard electroweak theory, as well as renormalisation group equations with a boundary matching condition, we derive a refined and more accurate value for the mass of the doubly-charged bilepton ($Y^{\pm \pm }$) occurring in the spontaneous breaking of the gauge group $SU(3{)}_L\times U(1{)}_X$ to the standard electroweak gauge group $SU(2{)}_L\times U(1{)}_Y$. Our result is $M(Y^{\pm \pm })=(1.29\pm 0.06)$ TeV.

   hep-phMod.Phys.Lett.A(2021)·5 citations
3. 03*

   The Search for Feebly-Interacting Particles

   Gaia Lanfranchi🇮🇹 · Maxim Pospelov🇺🇸 · Philip Schuster🇺🇸

   At the dawn of a new decade, particle physics faces the challenge of explaining the mystery of dark matter, the origin of matter over antimatter in the Universe, the apparent fine-tuning of the electro-weak scale, and many other aspects of fundamental physics. Perhaps the most striking frontier to emerge in the search for answers involves new physics at mass scales comparable to familiar matter, below the GeV scale, but with very feeble interaction strength. New theoretical ideas to address dark matter and other fundamental questions predict such feebly interacting particles (FIPs) at these scales, and indeed, existing data may even provide hints of this possibility. Emboldened by the lessons of the LHC, a vibrant experimental program to discover such physics is under way, guided by a systematic theoretical approach firmly grounded on the underlying principles of the Standard Model. We give an overview of these efforts, their motivations, and the decadal goals that animate the community involved in the search for FIPs, with special focus on accelerator-based experiments.

   hep-phAnn.Rev.Nucl.Part.Sci.(2021)·180 citations
4. 04*

   Critical exponents and transport properties near the QCD critical endpoint from the statistical bootstrap model

   Guruprasad Kadam🇮🇳 · Hiranmaya Mishra🇮🇳 · Marco Panero🇮🇹

   We present an estimate of the behaviour of the shear and bulk viscosity coefficients when the QCD critical point is approached from the hadronic side, describing hadronic matter within the statistical bootstrap model (SBM) of strong interactions. The boostrap model shows critical behavior near the quark-hadron transition temperature if the parameter characterizing the degeneracy of Hagedorn states is properly chosen. We calculate the critical exponents and amplitudes of relevant thermodynamic quantities near the QCD critical point and combine them with an Ansatz for the shear and bulk viscosity coefficients to derive the behavior of these coefficients near the critical point. The shear viscosity to entropy density ratio is found to decrease when the temperature is increased, and to approach the Kovtun-Son-Starinets bound 1/(4{\pi}) faster near the critical point, while the bulk viscosity coefficient is found to rise very rapidly.

   hep-phnucl-thEPJC(2021)·7 citations
5. 05*

   Modifications on the Properties of $D_{s0}^{\ast }(2317)$ as Four-quark State in Thermal Medium

   A. Türkan🇹🇷 · J.Y. Süngü🇹🇷 · E. Veli Veliev🇹🇷

   Since the low mass of $D_{s0}^{\ast }(2317)$ has still been a problem to the conventional quark model, one can consider other options regarding as multi-quark system. Therefore we investigate the scalar open-charm state $D_{s0}^{\ast }(2317)$ by Thermal QCD Sum Rules (TQCDSR) method using the two-point correlation function together with contributions of the non-perturbative condensates up to dimension six. Deriving and numerically analyzing thermal mass and pole residue sum rules, we accomplish the effects on the properties of $D_{s0}^{\ast }(2317)$ resonance in hot medium. Our numerical evaluations indicate that the variations in mass and pole residue values are stable through the growing temperature up to $T\cong 100\mathrm{MeV}$, but they begin to fall after this point. At critical temperature, the values of mass and pole residue change up to $91\%,70\%$ of their values in vacuum in the molecular scenario and $91\%,69\%$ in the diquark-antidiquark scenario. Our results does not give any definite information as to whether $D_{s0}^{\ast }(2317)$ resonance has molecular or diquark-antidiquark structure since they are very close to each other to differentiate them. Besides, we predict the hadronic parameters of the bottom partner of the $D_{s0}^{\ast }(2317)$ resonance in both molecular and diquark-antidiquark pictures. This bound state is worth investigating in future experiments. Also the detailed search of hot medium effects on the hadronic parameters of open-charm meson $D_{s0}^{\ast }(2317)$ and the bottom partner could have some implications to define the QCD phase diagram obtained from heavy-ion collision experiments. Moreover these results can be useful in distinguishing conventional quark model mesons from exotica.

   hep-phActa Phys.Polon.B(2022)·3 citations
6. 06*

   Gluon imaging using azimuthal correlations in diffractive scattering at the Electron-Ion Collider

   Heikki Mäntysaari🇫🇮 · Kaushik Roy🇩🇪 · Farid Salazar🇺🇸 · Björn Schenke🇺🇸

   We study coherent diffractive photon and vector meson production in electron-proton and electron-nucleus collisions within the Color Glass Condensate effective field theory. We show that electron-photon and electron-vector meson azimuthal angle correlations are sensitive to non-trivial spatial correlations in the gluon distribution of the target, and perform explicit calculations using spatially dependent McLerran-Venugopalan initial color charge configurations coupled to the numerical solution of small $x$ JIMWLK evolution equations. We compute the cross-section differentially in $Q^2$ and $|t|$ and find sizeable anisotropies in the electron-photon and electron-$\mathrm{J}/\psi$ azimuthal correlations ($v_{1,2}\approx 2-10\%$) in electron-proton collisions for the kinematics of the future Electron-Ion Collider. In electron-gold collisions these modulations are found to be significantly smaller ($v_{1,2}<0.1\%$). We also compute incoherent diffractive production where we find that the azimuthal correlations are sensitive to fluctuations of the gluon distribution in the target.

   hep-phnucl-thPRD(2021)·73 citations
7. 07*

   Fixing the vector coupling constant $g_{\rho }=5.0$ in the NJL model and final-state interactions in processes $\rho \to e^{+}{e}^{-}[{\mu }^{+}{\mu }^{-}]$, $\rho \to {\pi }^{+}{\pi }^{-}$, $\tau \to {\pi }^{-}{\pi }^0{\nu }_{\tau }$, and $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$

   M.K. Volkov🇷🇺 · A.B. Arbuzov🇷🇺 · K. Nurlan🇷🇺 · A.A. Pivovarov🇷🇺

   The possibility to use the width of the decay $\rho \to e^{+}{e}^{-}$ to fix the input parameter $g_{\rho }=5.0$ of the $SU(2)\times SU(2)$ chiral-symmetric Nambu--Jona-Lasinio model is discussed. It is shown that for a consistent simultaneous description of the processes $\rho \to e^{+}{e}^{-}$, $\rho \to {\pi }^{+}{\pi }^{-}$, ${\tau }^{-}\to {\pi }^{-}{\pi }^0{\nu }_{\tau }$, and $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$ can be constructed. Taking into account the interaction of pions in the final state appears to be important. The obtained theoretical results for the considered processes are in a satisfactory agreement with experimental data.

   hep-ph0 citations
8. 08*

   MARTY -- Modern ARtificial Theoretical phYsicist: A C++ framework automating symbolic calculations Beyond the Standard Model

   G. Uhlrich🇫🇷 · F. Mahmoudi🇫🇷 · A. Arbey🇫🇷

   Studies Beyond the Standard Model (BSM) will become more and more important in the near future with a rapidly increasing amount of data from different experiments around the world. The full study of BSM models is in general an extremely time-consuming task involving long and difficult calculations. It is in practice not possible to do exhaustive predictions in these models by hand, in particular if one wants to perform a statistical comparison with data and the SM. Here we present MARTY (Modern ARtificial Theoretical phYsicist), a new C++ framework that fully automates calculations from the Lagrangian to physical quantities such as amplitudes or cross-sections. This framework can fully simplify, automatically and symbolically, physical quantities in a very large variety of models. MARTY can also compute Wilson coefficients in effective theories. This will considerably facilitate the study of BSM models in flavor physics. Contrary to the existing public codes in this field MARTY aims to give a unique, free, open-source, powerful and user-friendly tool for high-energy physicists studying predictive BSM models, in effective or full theories up to the 1-loop level, which does not rely on any external package. With a few lines of code one can gather final expressions that may be evaluated numerically for statistical analysis. Features like automatic generation and manual edition of Feynman diagrams, comprehensive manual and documentation, clear and easy to handle user interface are amongst notable features of MARTY.

   hep-phComput.Phys.Commun.(2021)·33 citations
9. 09*

   Functional Prescription for EFT Matching

   Timothy Cohen🇺🇸 · Xiaochuan Lu🇺🇸 · Zhengkang Zhang🇺🇸

   We simplify the one-loop functional matching formalism to develop a streamlined prescription. The functional approach is conceptually appealing: all calculations are performed within the UV theory at the matching scale, and no prior determination of an Effective Field Theory (EFT) operator basis is required. Our prescription accommodates any relativistic UV theory that contains generic interactions (including derivative couplings) among scalar, fermion, and vector fields. As an example application, we match the singlet scalar extended Standard Model (SM) onto SMEFT.

   hep-phhep-thJHEP(2021)·79 citations
10. 10*

    Testing Leptoquark/EFT in $\bar{B}\to D^{(\ast )}l\bar{\nu }$ at the LHC

    Syuhei Iguro🇯🇵 · Michihisa Takeuchi🇯🇵 · Ryoutaro Watanabe🇮🇹

    We investigate the current LHC bounds on New Physics (NP) that contributes to $\bar{B}\to D^{(\ast )}l\bar{\nu }$ for $l=(e,\mu ,\tau )$ by considering both leptoquark (LQ) models and an effective-field-theory (EFT) Hamiltonian. Experimental analyses from $l+\text{missing}$ searches with high $p_T$ are applied to evaluate the NP constraints with respect to the Wilson coefficients. A novel point of this work is to show difference between LQs and EFT for the applicable LHC bound. In particular, we find that the EFT description is not valid to search for LQs with the mass less than $\lesssim 10\text{TeV}$ at the LHC and leads to overestimated bounds. We also discuss future prospects of high luminosity LHC searches including the charge asymmetry of background and signal events. Finally, a combined summary for the flavor and LHC bounds is given, and then we see that in several NP scenarios the LHC constraints are comparable with the flavor ones.

    hep-phhep-exEPJC(2021)·69 citations
11. 11*

    Intimate Relationship Between Sterile Neutrino Dark Matter and $\Delta N_{\mathrm{eff}}$

    Kevin J. Kelly🇺🇸 · Manibrata Sen🇺🇸 · Yue Zhang🇨🇦

    The self-interacting neutrino hypothesis is well motivated for addressing the tension between the origin of sterile neutrino dark matter and indirect detection constraints. It can also result in a number of testable signals from the laboratories to the cosmos. We explore a model of neutrino self-interaction mediated by a Majoron-like scalar with sub-MeV mass, and show that explaining the relic density of sterile neutrino dark matter implies a lower bound on the amount of extra radiation in early universe, in particular $\Delta N_{\mathrm{eff}}>0.12$ at the CMB epoch. This lower bound will be further strengthened with an improved $X$-ray search at the Athena observatory. Such an intimate relationship will be unambiguously tested by the upcoming CMB-S4 project.

    hep-phastro-ph.COastro-ph.HEhep-exPRL(2021)·49 citations
12. 12*

    Gravitational origin of dark matter and Majorana neutrino mass with non-minimal quartic inflation

    Debasish Borah🇮🇳 · Suruj Jyoti Das🇮🇳 · Abhijit Kumar Saha🇮🇳

    We propose a minimal framework to address successful quartic inflation, dark matter (DM) production in the early universe and non-vanishing tiny Majorana neutrino mass from a common gravitational origin point of view. In this setup, the quartic inflation is revived successfully via non-minimal coupling of inflaton to gravity while the production of DM takes place from purely gravitational effects through a misalignment mechanism. The generation of light Majorana neutrino mass is aided by explicit breaking of global lepton number symmetry through Planck suppressed operators involving non-zero vacuum expectation value (VEV) of the inflaton field. We present a detailed study of the DM yield in presence of non-minimal inflation, considering both the metric and the Palatini formalisms of gravity wherever appropriate. We reach at some interesting and different results in the DM sector compared to the earlier works in the similar direction with minimal inflationary background. Restricting to the light DM regime ($\mathcal{O}(1)$ keV- $\mathcal{O}(100)$ MeV) where classical production is expected to dominate over the quantum production, we numerically predict the DM mass by varying the DM quartic and non-minimal coupling, to be consistent with relic density requirements. We also obtain some non-trivial dependence of DM phenomenology on some of the relevant parameters of the inflation sector {\it e.g.} non minimal coupling and inflaton VEV. To explore the dependence on inflationary parameters further, we also estimate the DM relic using the same mechanism for two other inflationary models consistent with latest data and observe that one of these models predicts different range of DM mass upto hundreds of TeV.

    hep-phastro-ph.COgr-qcPhys.Dark Univ.(2021)·3 citations
13. 13*

    Quantum Interference in Jet Substructure from Spinning Gluons

    Hao Chen🇨🇳 · Ian Moult🇺🇸 · Hua Xing Zhu🇨🇳

    Collimated sprays of hadrons, called jets, are an emergent phenomenon of Quantum Chromodynamics (QCD) at collider experiments, whose detailed internal structure encodes valuable information about the interactions of high energy quarks and gluons, and their confinement into color-neutral hadrons. The flow of energy within jets is characterized by correlation functions of energy flow operators, with the three-point correlator, being the first correlator with non-trivial shape dependence, playing a special role in unravelling the dynamics of QCD. In this Letter we initiate a study of the three-point energy correlator to all orders in the strong coupling constant, in the limit where two of the detectors are squeezed together. We show that by rotating the two squeezed detectors with respect to the third by an angle $\varphi$, a $\cos (2\varphi )$ dependence arising from the quantum interference between intermediate virtual gluons with $+/-$ helicity is imprinted on the detector. This can be regarded as a double slit experiment performed with jet substructure, and it provides a direct probe of the ultimately quantum nature of the substructure of jets, and of transverse spin physics in QCD. To facilitate our all-orders analysis, we adopt the Operator Product Expansion (OPE) for light-ray operators in conformal field theory and develop it in QCD. Our application of the light-ray OPE in real world QCD establishes it as a powerful theoretical tool with broad applications for the study of jet substructure.

    hep-phhep-exhep-thnucl-ex+1PRL(2021)·116 citations
14. 14*

    Dependence of Dark Matter - Electron Scattering on the Galactic Dark Matter Velocity Distribution

    Aria Radick🇺🇸 · Anna-Maria Taki🇺🇸 · Tien-Tien Yu🇺🇸

    The rate of dark matter-electron scattering depends on the underlying velocity distribution of the dark matter halo. Importantly, dark matter-electron scattering is particularly sensitive to the high-velocity tail, which differs significantly amongst the various dark matter halo models. In this work, we summarize the leading halo models and discuss the various parameters which enter them. We recommend updated values for these parameters based on recent studies and measurements. Furthermore, we quantify the dependence of the dark matter-electron scattering rate on the choice of halo model and parameters, and demonstrate how these choices propagate to the predicted cross-section limits. The rate is most sensitive to changes in the circular velocity v0; in silicon targets, we find that the changes in the rate predictions can range from O(0.01%) to O(100%) for contact interactions and O(10%) to O(100%) for long-range interactions.

    hep-phastro-ph.COhep-exJCAP(2021)·46 citations
15. 15*

    Two-Loop anomalous dimensions of QCD operators up to dimension-sixteen and Higgs EFT amplitudes

    Qingjun Jin🇨🇳 · Ke Ren🇨🇳 · Gang Yang🇨🇳

    We consider two-loop renormalization of high-dimensional Lorentz scalar operators in the gluonic sector of QCD. These operators appear also in the Higgs effective theory obtained by integrating out the top quark loop in the gluon fusion process. We first discuss the classification of operators and how to construct a good set of basis using both off-shell field theory method and on-shell form factor formalism. To study loop corrections, we apply efficient unitarity-IBP strategy and compute the two-loop minimal form factors of length-3 operators up to dimension sixteen. From the UV divergences of form factor results, we extract the renormalization matrices and analyze the operator mixing behavior in detail. The form factors we compute are also equivalent to Higgs plus three-gluon amplitudes that capture high-order top mass corrections in Higgs EFT. We obtain the analytic finite remainder functions which exhibit several universal transcendentality structures.

    hep-phhep-thJHEP(2021)·25 citations
16. 16*

    When Freeze-out occurs due to a non-Boltzmann suppression: A study of degenerate dark sector

    Anirban Biswas🇮🇳 · Sougata Ganguly🇮🇳 · Sourov Roy🇮🇳

    Exponential suppression or commonly known as the Boltzmann suppression in the number density of dark matter is the key ingredient for creating chemical imbalance prior to the usual thermal freeze-out. A degenerate/quasi-degenerate dark sector can experience a different exponential suppression in the number density analogous to the radioactive decay law leading to a delayed freeze-out mechanism of dark matter known as the co-decaying dark matter. In this work, we study the dynamics of a multicomponent dark matter from thermally decoupled degenerate dark sector in a hidden U$(1{)}_X$ extension of the Standard Model. We compute the relic density of dark matter frozen-out through the co-decaying mechanism by solving four coupled Boltzmann equations. We demonstrate how temperature $T^{\prime }$ of the dark sector changes due to all types of $3\to 2$ and $2\to 2$ interactions along with the eternal expansion of the Universe. We find that $3\to 2$ interactions enhance $T^{\prime }$ by producing energetic particles in the dark sector while the excess heat is transferred by $2\to 2$ interactions to the entire dark sector. As the direct detection is possible only through the feeble portal couplings, we investigate the neutrino and $\gamma$-ray signals from dark matter annihilation via one step cascade processes and compare our results with the measured fluxes of atmospheric neutrinos by Super-Kamiokande and diffuse $\gamma$-rays by Fermi-LAT, EGRET, INTEGRAL collaborations. We find that the present scenario easily evades all the existing bounds from atmospheric neutrino and diffuse $\gamma$-ray observations for degenerate dark sector. However, the constraints are significant for quasi degenerate scenario.

    hep-phastro-ph.COJHEP(2021)·4 citations
17. 17*

    Learning to Identify Electrons

    Julian Collado🇺🇸 · Jessica N. Howard🇺🇸 · Taylor Faucett🇺🇸 · Tony Tong🇺🇸 · Pierre Baldi🇺🇸 · Daniel Whiteson🇺🇸

    We investigate whether state-of-the-art classification features commonly used to distinguish electrons from jet backgrounds in collider experiments are overlooking valuable information. A deep convolutional neural network analysis of electromagnetic and hadronic calorimeter deposits is compared to the performance of typical features, revealing a $\approx 5\%$ gap which indicates that these lower-level data do contain untapped classification power. To reveal the nature of this unused information, we use a recently developed technique to map the deep network into a space of physically interpretable observables. We identify two simple calorimeter observables which are not typically used for electron identification, but which mimic the decisions of the convolutional network and nearly close the performance gap.

    ↳ physics.data-anhep-exhep-phPRD(2021)·18 citations
18. 18*

    Gravitational memory effects in Brans-Dicke theory

    Shaoqi Hou🇨🇳

    There exist gravitational memory effects in Brans-Dicke theory. They are closely related to the Bondi-Metzner-Sachs symmetries living on the null infinity in an isolated system. By studying the asymptotically flat spacetime in Brans-Dicke theory and the asymptotic symmetries, one discovers that the displacement memory effect in the tensor sector is due to the vacuum transition caused by the null energy fluxes panetrating the null infinity, while in the scalar sector, the vacuum transition is due to the angular momentum fluxes. Together with the spin and the center-of-mass memory effects, the displacement memories are constrained by various flux-balance laws.

    ↳ gr-qchep-phhep-thAstron.Nachr.(2021)·21 citations
19. 19*

    Constrained extrapolation problem and order-dependent mappings

    Corbinian Wellenhofer🇩🇪 · Daniel R. Phillips🇺🇸 · Achim Schwenk🇩🇪

    We consider the problem of extrapolating the perturbation series for the dilute Fermi gas in three dimensions to the unitary limit of infinite scattering length and into the BEC region, using the available strong-coupling information to constrain the extrapolation problem. In this constrained extrapolation problem (CEP) the goal is to find classes of approximants that give well converged results already for low perturbative truncation orders. First, we show that standard Padé and Borel methods are too restrictive to give satisfactory results for this CEP. A generalization of Borel extrapolation is given by the so-called Maximum Entropy extrapolation method (MaxEnt). However, we show that MaxEnt requires extensive elaborations to be applicable to the dilute Fermi gas and is thus not practical for the CEP in this case. Instead, we propose order-dependent-mapping extrapolation (ODME) as a simple, practical, and general method for the CEP. We find that the ODME approximants for the ground-state energy of the dilute Fermi gas are robust with respect to changes of the mapping choice and agree with results from quantum Monte Carlo simulations within uncertainties.

    ↳ cond-mat.quant-gashep-phnucl-thPhys.Status Solidi B(2021)·4 citations
20. 20*

    Effects of Short-Distance Modifications to General Relativity in Spinning Binary Systems

    Aline Nascimento Lins🇧🇷 · Riccardo Sturani🇧🇷

    We investigate the possibility of testing short distance modifications to General Relativity via higher curvature terms in the fundamental gravity Lagrangian by analysing their impact on observations of spinning astronomical binary systems. By using effective field theory methods applied to the 2-body problem, generic lower bounds on the short-distance scale accompanying high curvature terms can be set. In particular we extend known results by deriving spin-dependent effects in binding energy, radiation emission process, and spin precession equations in binary systems, which are the fundamental ingredients to observe spin-dependent effects in gravitational wave detections from compact binary coalescences and spin precession in double binary pulsars.

    ↳ gr-qchep-phPRD(2021)·8 citations
21. 21*

    Energy loss of heavy quarkonia in hot QCD plasmas

    Juhee Hong🇰🇷 · Su Houng Lee🇰🇷

    We compute the energy loss of heavy quarkonia in high temperature QCD plasmas and investigate the energy loss effects on quarkonium suppression. Based on the effective vertex derived from the Bethe-Salpeter amplitude for quarkonium, the collisional and radiative energy loss are determined by quarkonium-gluon elastic scattering and the associated gluon-bremsstrahlung, respectively. In the energy regime $E<m_{{\rm Y}}^2/T$ the collisional energy loss is dominant over the radiative one, and the total energy loss increases with the plasma temperature and the initial energy of quarkonium. Our numerical analysis indicates that the medium-induced energy loss of the ${\rm Y}$(1S) results in stronger suppression at higher momentum, although the energy loss effects are found to be small compared with the previous estimates of quarkonium dissociation in heavy-ion collisions.

    ↳ nucl-thhep-phPRC(2021)·2 citations
22. 22*

    Testing the mechanism of lepton compositness

    Vincenzo Afferrante🇦🇹 · Axel Maas🇦🇹 · René Sondenheimer🇦🇹 · Pascal Törek🇦🇹

    Strict gauge invariance requires that physical left-handed leptons are actually bound states of the elementary left-handed lepton doublet and the Higgs field within the standard model. That they nonetheless behave almost like pure elementary particles is explained by the Fröhlich-Morchio-Strocchi mechanism. Using lattice gauge theory, we test and confirm this mechanism for fermions. Though, due to the current inaccessibility of non-Abelian gauged Weyl fermions on the lattice, a model which contains vectorial leptons but which obeys all other relevant symmetries has been simulated.

    ↳ hep-lathep-phSciPost Phys.(2021)·13 citations
23. 23*

    New positivity bounds from full crossing symmetry

    Andrew J. Tolley🇬🇧 · Zi-Yue Wang🇨🇳 · Shuang-Yong Zhou🇨🇳

    Positivity bounds are powerful tools to constrain effective field theories. Utilizing the partial wave expansion in the dispersion relation and the full crossing symmetry of the scattering amplitude, we derive several sets of generically nonlinear positivity bounds for a generic scalar effective field theory: We refer to these as the $PQ$, $D^{\mathrm{su}}$, $D^{\mathrm{stu}}$ and ${\bar{D}}^{\mathrm{stu}}$ bounds. While the $PQ$ bounds and $D^{\mathrm{su}}$ bounds only make use of the $s\leftrightarrow u$ dispersion relation, the $D^{\mathrm{stu}}$ and ${\bar{D}}^{\mathrm{stu}}$ bounds are obtained by further imposing the $s\leftrightarrow t$ crossing symmetry. In contradistinction to the linear positivity for scalars, these inequalities can be applied to put upper and lower bounds on Wilson coefficients, and are much more constraining as shown in the lowest orders. In particular we are able to exclude theories with soft amplitude behaviour such as weakly broken Galileon theories from admitting a standard UV completion. We also apply these bounds to chiral perturbation theory and we find these bounds are stronger than the previous bounds in constraining its Wilson coefficients.

    ↳ hep-thhep-phJHEP(2021)·246 citations
24. 24*

    Starburst galaxies strike back: a multi-messenger analysis with Fermi-LAT and IceCube data

    Antonio Ambrosone🇮🇹 · Marco Chianese🇳🇱 · Damiano F.G. Fiorillo🇮🇹 · Antonio Marinelli🇮🇹 · Gennaro Miele🇮🇹 · Ofelia Pisanti🇮🇹

    Starburst galaxies, which are known as "reservoirs" of high-energy cosmic-rays, can represent an important high-energy neutrino "factory" contributing to the diffuse neutrino flux observed by IceCube. In this paper, we revisit the constraints affecting the neutrino and gamma-ray hadronuclear emissions from this class of astrophysical objects. In particular, we go beyond the standard prototype-based approach leading to a simple power-law neutrino flux, and investigate a more realistic model based on a data-driven blending of spectral indexes, thereby capturing the observed changes in the properties of individual emitters. We then perform a multi-messenger analysis considering the extragalactic gamma-ray background (EGB) measured by Fermi-LAT and different IceCube data samples: the 7.5-year High-Energy Starting Events (HESE) and the 6-year high-energy cascade data. Along with starburst galaxies, we take into account the contributions from blazars and radio galaxies as well as the secondary gamma-rays from electromagnetic cascades. Remarkably, we find that, differently from the highly-constrained prototype scenario, the spectral index blending allows starburst galaxies to account for up to $40\%$ of the HESE events at $95.4\%$ CL, while satisfying the limit on the non-blazar EGB component. Moreover, values of $\mathcal{O}(100\mathrm{PeV})$ for the maximal energy of accelerated cosmic-rays by supernovae remnants inside the starburst are disfavoured in our scenario. In broad terms, our analysis points out that a better modeling of astrophysical sources could alleviate the tension between neutrino and gamma-ray data interpretation.

    ↳ astro-ph.HEhep-phMNRAS(2021)·69 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.