Mon·Dec 2, 2019Monday·December 2, 2019

1. 01*

   Natural dark matter and light bosons with an alternative left-right symmetry

   Mariana Frank🇨🇦 · Benjamin Fuks🇫🇷 · Özer Özdal🇨🇦

   We perform a consistent analysis of the alternative left-right symmetric model emerging from $E_6$ grand unification. We include a large set of theoretical and experimental constraints, with a particular emphasis on dark matter observables and collider signals. We show that the exotic neutrino inherent to this class of models, the scotino, is a viable candidate for dark matter satisfying relic density and direct detection constraints. This has strong implications on the scotino mass restricting it to lie in a narrow window, as well as on the spectrum of Higgs bosons, rendering it predictable, with a few light scalar, pseudoscalar and charged states. Moreover, we also show that the extra charged $W^{\prime }$ gauge boson can be light, and investigate the most promising signals at the future high-luminosity upgrade of the LHC. Our findings show that the most optimistic cosmologically-favoured scenarios should be observable at $5\sigma$, whilst others could leave visible hints provided the background is under good control at the systematical level.

   hep-phJHEP(2020)·15 citations
2. 02*

   Gauge Hierarchy

   Jihn E. Kim🇰🇷

   The chirality is the key for our world. In this scheme, I present a solution of the long standing gauge hierarchy problem with a hidden sector SU(5)${}^{\prime }$ with representations $\overline{10}\oplus \overline{5}\oplus 2\cdot 5$. Sideway remarks are on {\it NATURAL HILLTOP} inflation and a bound on the QCD angle $\bar{\theta }$.

   hep-phhep-thAIP Conf.Proc.(2021)·1 citation
3. 03*

   Charmed excited baryons with heavy-quark spin symmetry

   L. Tolos🇩🇪 · J. Nieves🇪🇸 · R. Pavao🇪🇸

   Recently five ${\Omega }_c$ excited states have been reported by the LHCb Collaboration, four of them corroborated by Belle. The Belle Collaboration has also discovered in 2017 one excited ${\Xi }_c$ with mass of 2930 MeV. In view of these recent detections, we analyze the possible molecular description of these states, using a unitarized baryon-meson model that incorporates both chiral and heavy-quark spin symmetries in a consistent manner. We pay a special attention to the renormalization procedure, so as to determine the robustness of our predictions. Within our model, we generate dynamically several ${\Omega }_c$ and ${\Xi }_c$ states. We find that, at least, three of our ${\Omega }_c$ states can be identified with the experimental ones and have spin-parity $J=1/2^{-}$ or $J=3/2^{-}$. Moreover, we find a plausible molecular description of not only the ${\Xi }_c(2930)$ state, but also ${\Xi }_c(2790)$, ${\Xi }_c(2815)$ and ${\Xi }_c(2970)$, reported in the PDG. Interestingly, we determine that ${\Xi }_c(2930)$ and ${\Xi }_c(2970)$ are heavy-quark spin partners with $J=1/2^{-}$ and $J=3/2^{-}$, respectively, while obtaining that ${\Xi }_c(2930)$, ${\Omega }_c(3090)$ or the ${\Omega }_c(3119)$, and ${\Sigma }_c(2800)$ would belong to the same SU(3) multiplet.

   hep-phhep-exnucl-exnucl-th0 citations
4. 04*

   The enigmatic $\Delta (1600)$ resonance

   B. Golli🇸🇮

   Our recently proposed model of the $\Delta (1600)$ resonance, in which the dominant component is a quasi-bound state of the $\Delta (1232)$ and the pion, is confronted with a similar model of the $N^{\ast }(1440)$ resonance as its counterpart in the P11 partial wave. We stress an essentially different mechanism responsible for generating the two resonances.

   hep-phnucl-thBled Workshops Phys.(2019)·0 citations
5. 05*

   The Minimal Supersymmetric Standard Model (MSSM) and General Singlet Extensions of the MSSM (GSEMSSM), a short review

   M. C. Rodriguez🇧🇷

   In this lectures, we give a review about the Minimal Supersymmetric Standard Model (MSSM) and the General Singlet Extensions of the MSSM (GSEMSSM). We, first introduce the minimal set of fields to built both models. Then we introduce their superfields and using them we build the lagrangian of those models in the superspace formalism. We show how to get the mass spectrum of those model in the $R$-parity scenarios and we also show how to get some Feynman Rules with the Gauge Bosons.

   hep-ph14 citations
6. 06*

   Improving the description of multiple interactions in Herwig

   Johannes Bellm🇸🇪 · Stefan Gieseke🇩🇪 · Patrick Kirchgaesser🇩🇪

   The modelling of multiple parton interactions in Monte Carlo event generators is a crucial part not only for the dressing of signal processes but also to describe data with a minimum bias on the event selection. Much work has and will be put into the theoretical framework and the numerical implementation of these models. In this contribution, we summarize various changes to the machinery of multiparton interactions and related physics in the Monte Carlo event generator Herwig 7.

   hep-phEPJC(2020)·23 citations
7. 07*

   Improved constraints on parton distributions using LHCb, ALICE and HERA heavy-flavour measurements and implications for the predictions for prompt atmospheric-neutrino fluxes

   O. Zenaiev🇩🇪 · M.V. Garzelli🇮🇹 · K. Lipka🇩🇪 · S.-O. Moch🇩🇪 · A. Cooper-Sarkar🇬🇧 · F. Olness🇺🇸 · A. Geiser🇩🇪 · G. Sigl🇩🇪

   The impact of measurements of heavy-flavour production in deep inelastic $ep$ scattering and in $pp$ collisions on parton distribution functions is studied in a QCD analysis at next-to-leading order. Recent combined results of inclusive and heavy-flavour production cross sections in deep inelastic scattering at HERA are investigated together with heavy-flavour production measurements at the LHC. Differential cross sections of charm- and beauty-hadron production measured by the LHCb collaboration at the centre-of-mass energies of 5, 7 and 13 TeV as well as the recent measurements of the ALICE experiment at the centre-of-mass energies of 5 and 7 TeV are explored. These data impose additional constraints on the gluon and the sea-quark distributions at low partonic fractions $x$ of the proton momentum, down to $x\approx 10^{-6}$. The impact of the resulting parton distribution function in the predictions for the prompt atmospheric-neutrino fluxes is studied.

   hep-phJHEP(2020)·60 citations
8. 08*

   Relativistic quantum mechanics description of neutrino spin-flavor oscillations in various external fields

   Maxim Dvornikov (IZMIRAN and Tomsk State University)🇷🇺

   We review the application of the relativistic quantum mechanics method for the description of neutrino oscillations for the studies of spin-flavor oscillations in background matter under the influence of a plane electromagnetic wave. Basing on the new exact solution of the Dirac-Pauli equation for a massive neutrino in the given external fields, we derive the transition probabilities for spin and spin-flavor oscillations. The obtained expressions are analyzed for different types of the neutrino magnetic moments. Our results are compared with findings of other authors.

   hep-phParticle Physics at the Year of 150th Ann…·0 citations
9. 09*

   Search for decaying eV-mass axion-like particles using gamma-ray signal from blazars

   A. Korochkin🇫🇷 · A. Neronov🇫🇷 · D. Semikoz🇫🇷

   Decaying axion-like particles (ALP) with masses in the eV range which might occupy dark matter halos of the Milky Way and other galaxies produce a characteristic "bump" feature in the spectrum of extragalactic background light (EBL). This feature leaves an imprint on the gamma-ray spectra of distant extragalactic sources. We derive constraints on the ALP coupling to photons based on analysis of spectra of very-high-energy gamma-ray loud blazars. We combine gamma-ray spectral measurements by Fermi/LAT and Cherenkov telescopes and fit a model in which the intrinsic source spectrum is modified by pair production on photons produced by ALP decays. We constrain the amplitude of gamma-ray flux suppression by this effect. We find that the combined Fermi/LAT and VERITAS data set for the source 1ES 1218+304 currently provides the tightest constraint on ALP-two-photon coupling which is complementary to the constraints imposed by non-observation of excess energy loss in Horizontal Branch stars, by the high-resolution spectroscopic observations of galaxy clusters with optical telescopes and by the searches of ALP signal with CERN Solar Axion Telescope. Our analysis favours existence of a bump in the EBL spectrum which could be produced by ALPs in the mass range 2-3 eV and axion-photon coupling $\sim 10^{-10}$ GeV${}^{-1}$. We discuss possibilities for verification of this hint with deeper Cherenkov telescope observations of large number of blazars with current generation instruments and with the Cherenkov Telescope Array.

   hep-phastro-ph.HEJCAP(2020)·28 citations
10. 10*

    Relativistic capture of dark matter by electrons in neutron stars

    Aniket Joglekar🇺🇸 · Nirmal Raj🇨🇦 · Philip Tanedo🇺🇸 · Hai-Bo Yu🇺🇸

    Dark matter can capture in neutron stars and heat them to observable luminosities. We study relativistic scattering of dark matter on highly degenerate electrons. We develop a Lorentz invariant formalism to calculate the capture probability of dark matter that accounts for the relativistic motion of the target particles and Pauli exclusion principle. We find that the actual capture probability can be five orders of magnitude larger than the one estimated using a nonrelativistic approach. For dark matter masses $10\mathrm{eV}\text{–}10\mathrm{PeV}$, neutron star heating complements and can be more sensitive than terrestrial direct detection searches. The projected sensitivity regions exhibit characteristic features that demonstrate a rich interplay between kinematics and Pauli blocking of the DM--electron system. Our results show that old neutron stars could be the most promising target for discovering leptophilic dark matter.

    hep-phastro-ph.HEPLB(2020)·99 citations
11. 11*

    The E6 route to multicomponent dark matter

    Triparno Bandyopadhyay🇮🇳 · Rinku Maji🇮🇳

    We present a framework of dark- and visible-sector unification in the E6 embedding of the standard model. The demand for consistently getting the standard model leads to the existence of the dark-sector. We show that the hierarchy of vevs typifying unified models leads to multicomponent dark matter at the IR. The symmetry breaking itself categorises the matter content into dark- and visible-sector particles, the categorisation being uniform across different breaking chains. We discuss the stability of the dark matter particles and compare them to existing phenomenological models of dark matter. The central results follow from symmetry and hierarchy arguments. We present an indicative set of models of gauge coupling unification, to show that the framework can be embedded in realistic models of E6.

    hep-phEPJC(2025)·7 citations
12. 12*

    Searching for dark photons in hyperon decays

    Jhih-Ying Su🇹🇼 · Jusak Tandean🇹🇼

    That massless dark photons could exist and have flavor-changing magnetic-dipole interactions with down-type light quarks is an attractive possibility which may be realized in various new-physics scenarios. It is potentially testable not only in kaon processes but also via two-body hyperon decays involving missing energy carried away by the massless dark photon. We explore the latter within a simplified model approach and take into account constraints from the kaon sector. We find that the branching fractions of some of these hyperon modes are allowed to be as high as a few times $10^{-4}$. Such numbers are likely to be within the sensitivity reaches of ongoing experiments like BESIII and future ones at super charm-tau factories.

    hep-phhep-exnucl-thPRD(2020)·25 citations
13. 13*

    Centrality dependence of multiplicity fluctuations from a hydrodynamical approach

    Hong-Hao Ma🇨🇳 · Kai Lin🇨🇳 · Wei-Liang Qian🇧🇷 · Bin Wang🇨🇳

    As one of the possible signals for the whereabouts of the critical point on the QCD phase diagram, recently, the multiplicity fluctuations in heavy-ion collisions have aroused much attention. It is a crucial observable of the Beam Energy Scan program of the Relativistic Heavy Ion Collider. In this work, we investigate the centrality dependence of the multiplicity fluctuations regarding the recent measurements from STAR Collaboration. By employing a hydrodynamical approach, the present study is dedicated to the noncritical aspects of the phenomenon. To be specific, in addition to the thermal fluctuations, finite volume corrections, and resonance decay at the freeze-out surface, the model is focused on the properties of the hydrodynamic expansion of the system and the event-by-event initial fluctuations. It is understood that the real signal of the critical point can only be obtained after appropriately subtracting the background, the latter is investigated in the present work. Besides the experimental data, our results are also compared to those of the hadronic resonance gas, as well as transport models.

    hep-phnucl-thAdv.High Energy Phys.(2020)·3 citations
14. 14*

    The Radio Synchrotron Background -- A Cosmic Conundrum

    J. Singal

    It has recently become apparent that the background level of diffuse radio emission on the sky is significantly higher than the level that can result from known extragalactic radio source classes or our Galaxy given our current understanding of its large-scale structure.~ In contrast to the more well-known and well-constrained cosmological and astrophysical backgrounds at microwave, infrared, optical/UV, X-ray, and gamma-ray wavelengths, this ``radio synchrotron background'' at radio wavelengths provides clear motivation for considering the possibilities of new astrophysical sources and new particle-based emission mechanisms.

    ↳ astro-ph.COhep-ph0 citations
15. 15*

    BEC and antiparticles in a magnetized neutral vector boson gas at any temperature

    LC. Suarez-Gonzalez🇨🇺 · G. Quintero Angulo🇨🇺 · A. Perez Martinez🇨🇺 · H. Perez Rojas🇨🇺

    We study the thermodynamic properties of a relativistic magnetized neutral vector boson gas at any temperature. We analyse the effect of temperature as well as antiparticles in Bose-Einstein condensation. Astrophysical implications are discussed.

    ↳ astro-ph.HEhep-ph0 citations
16. 16*

    Unveiling the structure of pseudoscalar mesons

    Khépani Raya🇨🇳 · Lei Chang🇨🇳 · Minghui Ding🇮🇹 · Daniele Binosi🇮🇹 · Craig D. Roberts🇨🇳

    A valuable approach to the analysis of hadron physics observables is provided by QCD's equations-of-motion; namely, the Dyson-Schwinger equations. Drawing from a diverse collection of predictions, we revisit: $\gamma {\gamma }^{\ast }\to$ neutral pseudoscalar transition form factors, their corresponding valence-quark distribution amplitudes and a recent result on the pion distribution functions.

    ↳ nucl-thhep-ph2 citations
17. 17*

    Strange-Meson Spectroscopy at COMPASS

    S. Wallner (for the COMPASS Collaboration)🇩🇪

    COMPASS is a multi-purpose fixed-target experiment at CERN aimed at studying the structure and spectrum of hadrons. It has collected the so far world's largest data set on diffractive production of the $K^{-}{\pi }^{-}{\pi }^{+}$ decay, which in principle gives access to all kaon states. We performed an elaborate partial-wave analysis, using model-selection techniques to select the wave set based on a large systematically constructed pool of allowed partial waves. The partial-wave decomposition reveals signals in the mass region of well-known states, such as $K_1(1270)$ and $K_1(1400)$. In addition, we observe potential signals from excited states, such as $K_1(1650)$.

    ↳ hep-exhep-ph4 citations
18. 18*

    Transverse momentum broadening from the lattice

    Guy D. Moore🇩🇪 · Niels Schlusser🇩🇪

    We present a calculation of the transverse momentum broadening of a high-energy fundamental-representation particle, as calculated nonperturbatively within EQCD using the technique proposed by Caron-Huot and pioneered by Panero, Schäfer, and Rummukainen. Our results are continuum extrapolated and provided at four temperatures: 250 MeV, 500 MeV, 1 GeV, and 100 GeV.

    ↳ hep-lathep-phPRD(2020)·30 citations
19. 19*

    Wilson Loops and Integrability

    Hagen Münkler🇨🇭

    These notes provide an introduction toward Wilson loops in N=4 supersymmetric Yang-Mills theory with a focus toward their integrability properties. In addition to a brief discussion of exact results for the circular Wilson loop and the cusp anomalous dimension, the notes focus on non-local symmetries, utilizing the integrability of the minimal surface problem that appears at strong coupling. This work is based on lectures given at the Young Researchers Integrability School and Workshop 2018. To appear in a special issue of J. Phys. A.

    ↳ hep-thhep-phJ.Phys.A(2020)·4 citations
20. 20*

    Nucleon axial structure from lattice QCD

    Gunnar S. Bali🇩🇪 · Lorenzo Barca🇩🇪 · Sara Collins🇩🇪 · Michael Gruber🇩🇪 · Marius Löffler🇩🇪 · Andreas Schäfer🇩🇪 · Wolfgang Söldner🇩🇪 · Philipp Wein🇩🇪 · Simon Weishäupl🇩🇪 · Thomas Wurm🇩🇪

    We present a new analysis method that allows one to understand and model excited state contributions in observables that are dominated by a pion pole. We apply this method to extract axial and (induced) pseudoscalar nucleon isovector form factors, which satisfy the constraints due to the partial conservation of the axial current up to expected discretization effects. Effective field theory predicts that the leading contribution to the (induced) pseudoscalar form factor originates from an exchange of a virtual pion, and thus exhibits pion pole dominance. Using our new method, we can recover this behavior directly from lattice data. The numerical analysis is based on a large set of ensembles generated by the CLS effort, including physical pion masses, large volumes (with up to $96^3\times 192$ sites and $L{m}_{\pi }=6.4$), and lattice spacings down to $0.039\text{fm}$, which allows us to take all the relevant limits. We find that some observables are much more sensitive to the choice of parametrization of the form factors than others. On the one hand, the $z$-expansion leads to significantly smaller values for the axial dipole mass than the dipole ansatz (M_A^{\text{z-exp}}=1.02(10) \, \text{GeV} versus $M_A^{\text{dipole}}=1.31(8)\text{GeV}$). On the other hand, we find that the result for the induced pseudoscalar coupling at the muon capture point is almost independent of the choice of parametrization (g_P^{\star \ \text{z-exp}} = 8.68(45) and $g_P^{\star \text{dipole}}=8.30(24)$), and is in good agreement with both, chiral perturbation theory predictions and experimental measurement via ordinary muon capture. We also determine the axial coupling constant $g_A$.

    ↳ hep-lathep-phJHEP(2020)·135 citations
21. 21*

    Common Origin of Warm Dark Matter and Dark Radiation

    Manuel A. Buen-Abad🇺🇸 · Raymond T. Co🇺🇸 · Keisuke Harigaya🇺🇸

    We consider a cosmological scenario where a relativistic particle and a stable massive particle are simultaneously produced from the decay of a late-decaying particle after Big-Bang Nucleosynthesis but before matter-radiation equality. The relativistic and massive particles behave as dark radiation and warm dark matter, respectively. Due to a common origin, the warmness and abundances are closely related. We refer to the models that lead to such a scenario as Common Origin of Warm and Relativistic Decay Products (COWaRD). We show that COWaRD predicts a correlation between the amount of dark radiation and suppression of the large scale structure, which can be tested in future precision cosmology observations. We demonstrate that COWaRD is realized, as an example, in a class of supersymmetric axion models and that future observations by the next generation Cosmic Microwave Background, Large Scale Structure, and 21-cm surveys can reveal the structure of the theory.

    ↳ astro-ph.COhep-phJCAP(2020)·6 citations
22. 22*

    Compact Dark Matter Objects via $N$ Dark Sectors

    Gia Dvali🇩🇪 · Emmanouil Koutsangelas🇩🇪 · Florian Kuhnel🇩🇪

    We propose a novel class of compact dark matter objects in theories where the dark matter consists of multiple sectors. We call these objects $N$-MACHOs. In such theories neither the existence of dark matter species nor their extremely weak coupling to the observable sector represent additional hypotheses but instead are imposed by the solution to the Hierarchy Problem and unitarity. The crucial point is that particles from the same sector have non-trivial interactions but interact only gravitationally otherwise. As a consequence, the pressure that counteracts the gravitational collapse is reduced while the gravitational force remains the same. This results in collapsed structures much lighter and smaller as compared to the ordinary single-sector case. We apply this phenomenon to a dark matter theory that consists of $N$ dilute copies of the Standard Model. The solutions do not rely on an exotic stabilization mechanism, but rather use the same well-understood properties as known stellar structures. This framework also gives rise to new microscopic superheavy structures, for example with mass $10^8$g and size $10^{-13}$cm. By confronting the resulting objects with observational constraints, we find that, due to a huge suppression factor entering the mass spectrum, these objects evade the strongest constrained region of the parameter space. Finally, we discuss possible formation scenarios of $N$-MACHOs. We argue that, due to the efficient dissipation of energy on small scales, high-density regions such as ultra-compact mini-halos could serve as formation sites of $N$-MACHOs.

    ↳ astro-ph.COhep-phPRD(2020)·25 citations
23. 23*

    Mass Production of IIA and IIB dS Vacua

    Niccolò Cribiori🇦🇹 · Renata Kallosh🇺🇸 · Andrei Linde🇺🇸 · Christoph Roupec🇦🇹

    We describe several applications of the recently proposed mass production procedure, where multiple moduli are stabilized in a dS vacuum, in supergravity models inspired by string theory. The construction involves a small downshift of an initial supersymmetric Minkowski minimum to a supersymmetric AdS minimum, and a consequent small uplift to a dS minimum. Our type IIA examples include dS stabilization in a 7-moduli model with $[SL(2,\mathbb{R}){]}^7$ tree level symmetry, and its simplified version, a 3-moduli STU model. In these models, we use uplifting anti-D6 branes. In type IIB models, we present 2- and 3-moduli examples of stable dS vacua in CY three-folds, with an uplifting anti-D3 brane. These include K3 fibration models, a CICY model and a multi-hole Swiss cheese model. We also address the issue whether this procedure is limited to a very small parameter range or if large deviations from the progenitor Minkowski vacuum are possible.

    ↳ hep-thgr-qchep-phJHEP(2020)·12 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.