Wed·Oct 14, 2020Wednesday·October 14, 2020

1. 01*

   The ScotoSinglet Model: A Scalar Singlet Extension of the Scotogenic Model

   Ankit Beniwal🇧🇪 · Juan Herrero-García🇪🇸 · Nicholas Leerdam🇦🇺 · Martin White🇦🇺 · Anthony G. Williams🇦🇺

   The Scotogenic Model is one of the most minimal models to account for both neutrino masses and dark matter (DM). In this model, neutrino masses are generated at the one-loop level, and in principle, both the lightest fermion singlet and the lightest neutral component of the scalar doublet can be viable DM candidates. However, the correct DM relic abundance can only be obtained in somewhat small regions of the parameter space, as there are strong constraints stemming from lepton flavour violation, neutrino masses, electroweak precision tests and direct detection. For the case of scalar DM, a sufficiently large lepton-number-violating coupling is required, whereas for fermionic DM, coannihilations are typically necessary. In this work, we study how the new scalar singlet modifies the phenomenology of the Scotogenic Model, particularly in the case of scalar DM. We find that the new singlet modifies both the phenomenology of neutrino masses and scalar DM, and opens up a large portion of the parameter space of the original model.

   hep-phJHEP(2020)·34 citations
2. 02*

   $\bar{B}\to X_s\gamma$ in BLMSSM

   Jian-Bin Chen🇨🇳 · Meng Zhang🇨🇳 · Li-Li Xing🇨🇳 · Tai-Fu Feng🇨🇳 · Shu-Min Zhao🇨🇳 · Ke-Sheng Sun🇨🇳

   Applying the effective Lagrangian method, we study the Flavor Changing Neutral Current $b\to s\gamma$ within the minimal supersymmetric extension of the standard model where baryon and lepton numbers are local gauge symmetries. Constraints on the parameters are investigated numerically with the experimental data on branching ratio of $\bar{B}\to X_s\gamma$. Additionally, we present the corrections to direct CP-violation in $\bar{B}\to X_s\gamma$ and time-dependent CP-asymmetry in $B\to K^{\ast }\gamma$. With appropriate assumptions on parameters, we find the direct CP-violation $A_{CP}$ is very small, while one-loop contributions to $S_{K^{\ast }\gamma }$ can be significant.

   hep-phCPC(2021)·1 citation
3. 03*

   Two-Higgs doublet solution to the LSND, MiniBooNE and muon $g-2$ anomalies

   Waleed Abdallah🇮🇳 · Raj Gandhi🇮🇳 · Samiran Roy🇮🇳

   We show that one of the simplest extensions of the Standard Model, the addition of a second Higgs doublet, when combined with a dark sector singlet scalar, allows us to: $i)$ explain the long-standing anomalies in the Liquid Scintillator Neutrino Detector (LSND) and MiniBooNE (MB) while maintaining compatibility with the null result from KARMEN, $ii)$ obtain, in the process, a portal to the dark sector, and $iii)$ comfortably account for the observed value of the muon $g-2$. Three singlet neutrinos allow for an understanding of observed neutrino mass-squared differences via a Type I seesaw, with two of the lighter states participating in the interaction in both LSND and MB. We obtain very good fits to energy and angular distributions in both experiments. We explain features of the solution presented here and discuss the constraints that our model must satisfy. We also mention prospects for future tests of its particle content.

   hep-phhep-exPRD(2021)·62 citations
4. 04*

   Low scale leptogenesis in a model with promising $CP$ structure

   Daijiro Suematsu🇯🇵

   We consider a simple extension of the standard model, which could give a solution to its $CP$ issues through both the Peccei-Quinn mechanism and the Nelson-Barr mechanism. Its low energy effective model coincides with the scotogenic model in the leptonic sector. Although leptogenesis is known not to work well at lower reheating temperature than $10^9$ GeV in simple seesaw and scotogenic frameworks, such low reheating temperature could be consistent with both neutrino mass generation and thermal leptogenesis via newly introduced fields without referring to the resonance effect. An alternative dark matter candidate to axion is prepared as an indispensable ingredient of the model.

   hep-phEPJC(2021)·5 citations
5. 05*

   Effect of sterile phases on degeneracy resolution capabilities of LBL experiments

   Akshay Chatla🇮🇳 · Bindu A. Bambah🇮🇳

   In sterile neutrino (3+1) parameterisation, we observe that sterile phases (${\delta }_{14},{\delta }_{24}$) are always together in oscillation probability, even when the MSW effect is considered. We see that the difference between the sterile phases has a more dominating effect over event rates compared to small variations due to changes in individual values. In this work, we show the value of sterile phase difference (${\delta }_{14}-{\delta }_{24}$) that least affects the parameter degeneracy resolution of ${\delta }_{13},{\theta }_{23}$ at long-baseline experiments.

   hep-phPhys.Atom.Nucl.(2021)·1 citation
6. 06*

   Heavy Light Inflaton and Dark Matter Production

   Fedor Bezrukov🇬🇧 · Abigail Keats🇬🇧

   We study the minimal extension of the SM by a scalar with quartic interaction serving as an inflaton. For the model where scale symmetry is broken only in the inflaton sector, the mass of the inflaton is constrained to be relatively low. Here, we analysed the previously omitted situation of the inflaton masses $m_{\chi }\gtrsim 250\text{ GeV}$. Therefore, we provide a window of inflaton masses with viable inflationary properties that evade direct observational constraints, due to their small mixing with the Higgs sector. The addition of heavy neutral leptons with Majorana masses induced by the interaction with the inflaton allow for Cold Dark Matter in the model with masses $O(1-10)\text{ MeV}$.

   hep-phPRD(2020)·4 citations
7. 07*

   Simulation-based inference methods for particle physics

   Johann Brehmer🇺🇸 · Kyle Cranmer🇺🇸

   Our predictions for particle physics processes are realized in a chain of complex simulators. They allow us to generate high-fidelity simulated data, but they are not well-suited for inference on the theory parameters with observed data. We explain why the likelihood function of high-dimensional LHC data cannot be explicitly evaluated, why this matters for data analysis, and reframe what the field has traditionally done to circumvent this problem. We then review new simulation-based inference methods that let us directly analyze high-dimensional data by combining machine learning techniques and information from the simulator. Initial studies indicate that these techniques have the potential to substantially improve the precision of LHC measurements. Finally, we discuss probabilistic programming, an emerging paradigm that lets us extend inference to the latent process of the simulator.

   hep-phhep-exphysics.data-anstat.ML32 citations
8. 08*

   Probing Dark Sector CP Violation with Electric Dipole Moments and Colliders

   Carlos Henrique de Lima🇨🇦 · Ben Keeshan🇨🇦 · Heather E. Logan🇨🇦 · Yue Zhang🇨🇦

   We study the experimental constraints on dark sector CP violation that enters the visible sector through a Higgs portal coupling $H^{†}H{Z}_{\mu \nu }^{\prime }{\tilde{Z}}^{\prime \mu \nu }$, where the $Z^{\prime }$ is from a new U(1) gauge symmetry which is assumed to couple to lepton number. We compute explicitly the leading two-loop contribution of this effective operator to the electron electric dipole moment (EDM) and show that the resulting constraints are comparable to those from direct $Z^{\prime }$ searches at electron-positron colliders when the effective operator is generated at tree level. We also examine an explicit UV completion for this effective operator that was first introduced to achieve electroweak baryogenesis and show that collider constraints from $B$-factories already exclude viable baryogenesis for $Z^{\prime }$ masses below 10 GeV, and that future electron-positron Higgs factories will exclude viable baryogenesis for $Z^{\prime }$ masses up to the $e^{+}{e}^{-}$ center-of-mass energy if anticipated luminosities are achieved. For higher $Z^{\prime }$ masses, the full viable baryogenesis parameter space lies within six orders of magnitude of the current upper bound on the electron EDM.

   hep-phPRD(2021)·5 citations
9. 09*

   Quantum simulation of oscillating neutrinos

   Abhishek Kumar Jha🇮🇳 · Akshay Chatla🇮🇳 · Bindu A. Bambah🇮🇳

   Two and three flavor oscillating neutrinos are shown to exhibit the properties bipartite and tripartite quantum entanglement. The two and three flavor neutrinos are mapped to qubit states used in quantum information theory. Such quantum bits of the neutrino state can be encoded on a IBMQ computer using quantum computing as a tool. We show the implementation of entanglement in the two neutrino system on the IBM quantum processor.

   hep-phhep-exquant-ph6 citations
10. 10*

    Scalar Leptoquarks in Leptonic Processes

    Andreas Crivellin🇨🇭 · Christoph Greub🇨🇭 · Dario Müller🇨🇭 · Francesco Saturnino🇨🇭

    Leptoquarks are hypothetical new particles, which couple quarks directly to leptons. They experienced a renaissance in recent years as they are prime candidates to explain the so-called \textit{flavor anomalies}, i.e. the deviations between the Standard Model predictions and measurements in $b\to s{\ell }^{+}{\ell }^{-}$ and $b\to c\tau \nu$ processes and in the anomalous magnetic moment of the muon. At the one-loop level these particles unavoidably generate effects in the purely leptonic processes like $Z\to {\ell }^{+}{\ell }^{-}$, $Z\to \nu \bar{\nu }$, $W\to \ell \nu$ and $h\to {\ell }^{+}{\ell }^{-}$ and can even generate non-zero rates for lepton flavor violating processes such as $\ell \to {\ell }^{\prime }\gamma$, $Z\to {\ell }^{+}{\ell }^{\prime -}$, $h\to {\ell }^{+}{\ell }^{\prime -}$ and $\ell \to 3{\ell }^{\prime }$. In this article we calculate these processes for all five representations of scalar Leptoquarks. We include their most general interaction terms with the Standard Model Higgs boson, which leads to Leptoquark mixing after the former acquires a vacuum expectation value. In our phenomenological analysis we investigate the effects in modified lepton couplings to electroweak gauge bosons, we study the correlations of the anomalous magnetic moment of the muon with $h\to {\mu }^{+}{\mu }^{-}$ and $Z\to {\mu }^{+}{\mu }^{-}$ as well as the interplay between different lepton flavor violating decays.

    hep-phhep-exJHEP(2021)·75 citations
11. 11*

    Production of axion-like particles from photon conversions in large-scale solar magnetic fields

    Ersilia Guarini (Bari Univ.)🇮🇹 · Pierluca Carenza (Bari Univ. & INFN Bari)🇮🇹 · Javier Galan (Zaragoza Univ.)🇪🇸 · Maurizio Giannotti (Barry Univ.)🇺🇸 · Alessandro Mirizzi (Bari Univ. & INFN Bari)🇮🇹

    The Sun is a well-studied astrophysical source of axion-like particles (ALPs), produced mainly through the Primakoff process. Moreover, in the Sun there exist large-scale magnetic fields that catalyze an additional ALP production via a coherent conversion of thermal photons. We study this contribution to the solar ALP emissivity, typically neglected in previous investigations. Furthermore, we discuss additional bounds on the ALP-photon coupling from energy-loss arguments, and the detection perspectives of this new ALP flux at future helioscope and dark matter experiments.

    hep-phastro-ph.SRPRD(2020)·41 citations
12. 12*

    Gauge independence of the physical fermion mass in the effective action of theories with radiative symmetry breaking

    Dimitrios Metaxas🇬🇷

    I consider an Abelian gauge theory, with a complex scalar field and massless, chiral fermions, in the limit where the couplings and the interactions induce radiative symmetry breaking, and I derive and verify the Nielsen identities that ensure the gauge independence of the physical fermion mass that emerges in the broken phase of the effective action.

    hep-phhep-thPLB(2021)·3 citations
13. 13*

    Oscillon collapse to black holes

    Zainab Nazari🇮🇹 · Michele Cicoli🇮🇹 · Katy Clough🇬🇧 · Francesco Muia🇬🇧

    Using numerical relativity simulations we study the dynamics of pseudo-topological objects called oscillons for a class of models inspired by axion-monodromy. Starting from free field solutions supported by gravitational attractions, we investigate the effect of adding self-interactions, and contrast this with the effect of adding self-interactions whilst removing gravitational support. We map out regions of the parameter space where the initial conditions rapidly collapse to black holes, and other regions where they remain pseudo-stable or disperse.

    ↳ gr-qchep-phhep-thJCAP(2021)·45 citations
14. 14*

    On the regularization of Lifshitz-type field theories

    Alfio Bonanno🇮🇹 · Miok Park🇰🇷 · Lesław Rachwał🇧🇷 · Dario Zappalà🇮🇹

    We consider Lifshitz-type scalar theories with explicit breaking of the Lorentz symmetry that, in addition, exhibit anisotropic scaling laws near the ultraviolet fixed point. Using the proper time regularization method on the spatial coordinates only, we derive the regularized form of the one-loop effective potential in such theories. We study the main features of the one-loop effective potential and, also, the RG flow of the scale-dependent potential both in the IR and UV regimes. The beta functions for the couplings are derived.

    ↳ hep-thgr-qchep-phmath-ph+2EPJC(2020)·1 citation
15. 15*

    Constraints on MeV dark matter and primordial black holes: Inverse Compton signals at the SKA

    Bhaskar Dutta🇺🇸 · Arpan Kar🇮🇳 · Louis E. Strigari🇺🇸

    We investigate the possibilities for probing MeV dark matter (DM) particles and primordial black holes (PBHs) (for masses $\sim 10^{15}$--$10^{17}$ g) at the upcoming radio telescope SKA, using photon signals from the Inverse Compton (IC) effect within a galactic halo. Pair-annihilation or decay of MeV DM particles (into $e^{+}{e}^{-}$ pairs) or Hawking radiation from a population of PBHs generates mildly relativistic $e^{\pm }$ which can lead to radio signals through the IC scattering on low energy cosmic microwave background (CMB) photons. We study the ability of SKA to detect such signals coming from nearby ultra-faint dwarf galaxies Segue I and Ursa Major II as well as the globular cluster $\omega$-cen and the Coma cluster. We find that with $\sim 100$ hours of observation, the SKA improves the Planck constraints on the DM annihilation/decay rate and the PBH abundance for masses in the range $\sim 1$ to few tens of MeV and above $10^{15}$ to $10^{17}$ g, respectively. Importantly, the SKA limits are independent of the assumed magnetic fields within the galaxies. Previously allowed regions of diffusion parameters of MeV electrons inside a dwarf galaxy that give rise to observable signals at the SKA are also excluded. For objects like dwarf galaxies, predicted SKA constraints depend on both the DM and diffusion parameters. Independent observations in different frequency bands, e.g., radio and $\gamma$-ray frequencies, may break this degeneracy and thus enable one to constrain the combined parameter space of DM and diffusion. However, the constraints are independent of diffusion parameters for galaxy clusters such as Coma.

    ↳ astro-ph.HEhep-phJCAP(2021)·26 citations
16. 16*

    MiniBooNE Neutrino Oscillation Search Results and Predicted Background Events

    Teppei Katori (for the MiniBooNE Collaboration)🇬🇧

    In this short review, we discuss the 2020 MiniBooNE electron neutrino appearance oscillation results with special attention on background predictions relevant to the MiniBooNE oscillation results and other (anti)electron neutrino appearance search experiments.

    ↳ hep-exhep-ph5 citations
17. 17*

    Surface and curvature properties of charged strangelets in compact objects

    G. Lugones🇧🇷 · A. G. Grunfeld🇦🇷

    Droplets of absolutely stable strange quark matter (strangelets) immersed in a lepton background may be the energetically preferred composition of strange star crusts and of the interior of a new class of stars known as strangelet dwarfs. In this work we calculate the surface tension $\sigma$ and the curvature coefficient $\gamma$ of charged strangelets as a function of the baryon number density, the temperature, the chemical potential of trapped neutrinos, the strangelet size, the electric potential and the electric charge at their boundary. Strange quark matter in chemical equilibrium and with global electric charge neutrality is described within the MIT bag model. We focus on three different astrophysical scenarios, namely cold strange stars, proto strange stars and post merger strange stars. Finite size effects are implemented within the multiple reflection expansion framework. We find that $\sigma$ decreases significantly as the strangelet's boundary becomes more positively charged. This occurs because $\sigma$ is dominated by the contribution of $s$ quarks which are the most massive particles in the system. Negatively charged $s$-quarks are suppressed in strangelets with a large positive electric charge, diminishing their contribution to $\sigma$ and resulting in smaller values of the total $\sigma$. We verify that the more extreme astrophysical scenarios, with higher temperatures and higher neutrino chemical potentials, allow higher positive values of the strangelet's electric charge at the boundary and consequently smaller values of $\sigma$. In contrast, $\gamma$ is strongly dominated by the density of light ($u$ and $d$) quarks and is quite independent of the charge-per-baryon ratio, the temperature and neutrino trapping. We discuss the relative importance of surface and curvature effects as well as some astrophysical consequences of these results.

    ↳ nucl-thastro-ph.HEhep-phhep-thPRC(2021)·19 citations
18. 18*

    Induced gravitational waves as a cosmological probe of the sound speed during the QCD phase transition

    Katsuya T. Abe🇯🇵 · Yuichiro Tada🇯🇵 · Ikumi Ueda🇯🇵

    The standard model of particle physics is known to be intriguingly successful. However their rich phenomena represented by the phase transitions (PTs) have not been completely understood yet, including the possibility of the existence of unknown dark sectors. In this Letter, we investigate the measurement of the equation of state parameter $w$ and the sound speed $c_{\mathrm{s}}$ of the PT plasma with use of the gravitational waves (GWs) of the universe. Though the propagation of GW is insensitive to $c_{\mathrm{s}}$ in itself, the sound speed value affects the dynamics of primordial density (or scalar curvature) perturbations and the induced GW by their horizon reentry can then be an indirect probe both $w$ and $c_{\mathrm{s}}$. We numerically reveal the concrete spectrum of the predicted induced GW with two simple examples of the scalar perturbation spectrum: the monochromatic and scale-invariant spectra. In the monochromatic case, we see that the resonant amplification and cancellation scales of the induced GW depend on the $c_{\mathrm{s}}$ values at different time respectively. The scale-invariant case gives a more realistic spectrum and its specific shape will be compared with observations. In particular, the QCD phase transition corresponds with the frequency range of the pulsar timing array (PTA) observations. If the amplitude of primordial scalar power is in the range of $10^{-4}\lesssim A_{\zeta }\lesssim 10^{-2}$, the induced GW is consistent with current observational constraints and detectable in the future observation in Square Kilometer Array. Futhermore the recent possible detection of stochastic GWs by NANOGrav 12.5 yr analysis~[1] can be explained by the induced GW if $A_{\zeta }\sim \sqrt{7}\times 10^{-3}$.

    ↳ astro-ph.COhep-phJCAP(2021)·59 citations
19. 19*

    On Filaments, Prolate Halos and Rotation Curves

    K. Zatrimaylov🇮🇹

    We propose a simple geometrical mechanism for the flattening of galactic rotation curves, the local compression of field lines around their planes induced either by the presence of thin string-like objects at the centers of galaxies or by elongated dark-matter halos, and elaborate on its possible role in Nature. We fit 83 rotation curves from the SPARC database with logarithmic potentials produced by a thin "wire" at the origin and then, after selecting 2 galaxies that yield the most interesting fits, analyze them with an alternative model, deformed versions of two popular models of dark-matter halos. Our conclusion is that the presence of a filament clearly improves the fit quality in a number of cases, while bulged dark matter profiles have a lesser effect. If taken at face value, these results would imply the presence of elongated mass distributions away from the galactic plane in a number of galaxies, and may also have some indirect impact on the controversy between cold dark matter (CDM), self-interacting dark matter (SiDM), and modified Newtonian dynamics (MOND).

    ↳ astro-ph.GAgr-qchep-phhep-thJCAP(2021)·4 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.