Tue·Sep 25, 2018Tuesday·September 25, 2018

1. 01*

   Axions and anomalous $U(1)$'s

   Quentin Bonnefoy🇫🇷 · Emilian Dudas🇫🇷

   Inspired by recent studies of high-scale decay constant or flavorful QCD axions, we review and clarify their existence in effective string models with anomalous $U(1)$ gauge groups. We find that such models, when coupled to charged scalars getting vacuum expectation values, always have one light axion, whose mass can only come from nonperturbative effects. If the main nonperturbative effect is from QCD, then it becomes a Peccei-Quinn axion candidate for solving the strong CP problem. We then study simple models with universal Green-Schwarz mechanism and only one charged scalar field: in the minimal gaugino condensation case the axion mass is tied to the supersymmetry breaking scale and cannot be light enough, but slightly refined models maintain a massless axion all the way down to the QCD scale. Both kinds of models can be extended to yield intermediate scale axion decay constants. Finally, we gauge flavorful axion models under an anomalous $U(1)$ and discuss the axion couplings which arise.

   hep-phhep-thInt.J.Mod.Phys.A(2018)·6 citations
2. 02*

   Magnetic field-dependence of the neutral pion mass in the linear sigma model coupled to quarks: The weak field case

   Alejandro Ayala🇲🇽 · Ricardo L. S. Farias🇧🇷 · S. Hernandez-Ortiz🇲🇽 · Luis A. Hernandez🇲🇽 · D. Manreza Paret🇲🇽 · R. Zamora🇨🇱

   We compute the neutral pion mass dependence on a magnetic field in the weak field approximation at one-loop order. The calculation is carried out within the linear sigma model coupled to quarks and using Schwinger's proper-time representation for the charged particle propagators. We find that the neutral pion mass decreases with the field strength provided the boson self-coupling magnetic field corrections are also included. The calculation should be regarded as the setting of the trend for the neutral pion mass as the magnetic field is turned on.

   hep-phhep-thnucl-thPRD(2018)·66 citations
3. 03*

   Are we overlooking Lepton Flavour Universal New Physics in $b\to s\ell \ell$ ?

   Marcel Algueró🇪🇸 · Bernat Capdevila🇪🇸 · Sébastien Descotes-Genon🇫🇷 · Pere Masjuan🇪🇸 · Joaquim Matias🇪🇸

   The deviations with respect to the Standard Model (SM) that are currently observed in $b\to s\ell \ell$ transitions (the so-called flavour anomalies) can be interpreted in terms of different New Physics (NP) scenarios within a model-independent effective approach. We reconsider the determination of NP in global fits from a different perspective by removing one implicit hypothesis of current analyses, namely that NP is only Lepton-Flavour Universality Violating (LFUV). We examine the roles played by LFUV NP and Lepton-Flavour Universal (LFU) NP altogether, providing new directions to identify the possible theory beyond the SM responsible for the anomalies observed. New patterns of NP emerge due to the possibility of allowing at the same time large LFUV and LFU NP contributions to $C_{10\mu }$, which provides a different mechanism to obey the constraint from the $B_s\to {\mu }^{+}{\mu }^{-}$ branching ratio. In this landscape of NP, we discuss how to discriminate among these scenarios in the short term thanks to current and forthcoming observables. While the update of $R_K$ will be a major milestone to confirm the NP origin of the flavour anomalies, additional observables, in particular the LFUV angular observable $Q_5$, turn out to be central to assess the precise NP scenario responsible for the observed anomalies.

   hep-phPRD(2019)·74 citations
4. 04*

   Predictions of $B_c\to (D,D^{\ast })l\nu$ decay observables in the standard model

   Rupak Dutta🇮🇳

   We study $B_c\to (D,D^{\ast })l\nu$ semileptonic decays mediated via $b\to ul\nu$ charged current interactions using the $B_c\to (D,D^{\ast })$ transition form factors obtained in the covariant light front quark model. We give predictions on the branching ratios, ratio of branching ratios, and various asymmetries pertaining to these decay modes within the standard model. These results can be tested in the ongoing or in the future experiments and can provide complimentary information regarding the observed anomalies in $B\to (D,D^{\ast })\tau \nu$ and $B_c\to J/\Psi \tau \nu$ decays.

   hep-phJ.Phys.G(2019)·9 citations
5. 05*

   Precise predictions for $t\bar{t}\gamma /t\bar{t}$ cross section ratios at the LHC

   G. Bevilacqua🇭🇺 · H. B. Hartanto🇬🇧 · M. Kraus🇩🇪 · T. Weber🇩🇪 · M. Worek🇩🇪

   With the goal of increasing the precision of NLO QCD predictions for the $pp\to t\bar{t}\gamma$ process in the di-lepton top quark decay channel we present theoretical predictions for the $\mathcal{R}={\sigma }_{t\bar{t}\gamma }/{\sigma }_{t\bar{t}}$ cross section ratio. Results for the latter together with various differential cross section ratios are given for the LHC with the Run II energy of $\sqrt{s}=13$ TeV. Fully realistic NLO computations for $t\bar{t}$ and $t\bar{t}\gamma$ production are employed. They are based on matrix elements for $e^{+}{\nu }_e{\mu }^{-}{\bar{\nu }}_{\mu }b\bar{b}$ and $e^{+}{\nu }_e{\mu }^{-}{\bar{\nu }}_{\mu }b\bar{b}\gamma$ processes and include all resonant and non-resonant diagrams, interferences, and off-shell effects of the top quarks and the $W$ gauge bosons. Various renormalisation and factorisation scale choices and parton density functions are examined to assess their impact on the cross section ratio. Depending on the transverse momentum cut on the hard photon a judicious choice of a dynamical scale allows us to obtain $1\%-3\%$ percent precision on $\mathcal{R}$. Moreover, for differential cross section ratios theoretical uncertainties in the range of $1\%-6\%$ have been estimated. Until now such high precision predictions have only been reserved for the top quark pair production at NNLO QCD. Thus, $\mathcal{R}$ at NLO in QCD represents a very precise observable to be measured at the LHC for example to study the top quark charge asymmetry or to probe the strength and the structure of the $t$-$\bar{t}$-$\gamma$ vertex. The latter can shed some light on possible new physics that can reveal itself only once sufficiently precise theoretical predictions are available.

   hep-phhep-exJHEP(2019)·48 citations
6. 06*

   On Approximation Methods in the Study of Boson Stars

   Joshua Eby🇮🇱 · Madelyn Leembruggen🇺🇸 · Lauren Street🇺🇸 · Peter Suranyi🇺🇸 · L.C.R. Wijewardhana🇺🇸

   We analyze the accuracy of the variational method in computing physical quantities relevant for gravitationally bound Bose-Einstein condensates. Using a variety of variational ansätze found in existing literature, we determine physical quantities and compare them to exact numerical solutions. We conclude that a "linear+exponential" wavefunction proportional to $(1+\xi )\exp (-\xi )$ (where $\xi$ is a dimensionless radial variable) is the best fit for attractive self-interactions along the stable branch of solutions, while for small particle number $N$ it is also the best fit for repulsive self-interactions. For attractive self-interactions along the unstable branch, a single exponential is the best fit for small $N$, while a sech wavefunction fits better for large $N$. The Gaussian wavefunction ansatz, which is used often in the literature, is exceedingly poor across most of the parameter space, with the exception of repulsive interactions for large $N$. We investigate a "double exponential" ansatz with a free constant parameter, which is computationally efficient and can be optimized to fit the exact solutions in different limits. We show that the double exponential can be tuned to fit the sech ansatz, which is computationally slow. We also show how to generalize the addition of free parameters in order to create more computationally efficient ansätze using the double exponential. Determining the best ansatz, according to several comparison parameters, will be important for analytic descriptions of dynamical systems. Finally, we examine the underlying relativistic theory, and critically analyze the Thomas-Fermi approximation often used in the literature.

   hep-phastro-ph.COPRD(2018)·36 citations
7. 07*

   Highly-boosted dark matter and cutoff for cosmic-ray neutrino through neutrino portal

   Wen Yin🇨🇳

   We study the cutoff for the cosmic-ray neutrino, set by the scattering with cosmic background neutrinos into dark sector particles through a neutrino portal interaction. We find that a large interaction rate is still viable, when the dark sector particles are mainly coupled to the $\tau -$neutrino, so that the neutrino mean free path can be reduced to be $O(10)$Mpc over a wide energy range. If stable enough, the dark sector particle, into which most of the cosmic-ray neutrino energy is transferred, can travel across the Universe and reach the earth. The dark sector particle can carry the energy as large as $\text{O}(\mathrm{EeV})$ if originates from a cosmogenic neutrino.

   hep-phastro-ph.HEhep-exEPJ Web Conf.(2019)·80 citations
8. 08*

   Towards Realistic SUSY Grand Unification for Extended MSSM

   Sibo Zheng🇨🇳

   Low-energy supersymmetric models such as MSSM, NMSSM and MSSM with vectorlike fermion are consistent with perturbative unification. While the non-minimal extensions naturally explain Higgs mass and dark matter in the low energy region, it is unclear how seriously they are constrained in the ultraviolet region. Our study shows that $i)$, In the case of embedding MSSM into $\mathrm{SU}(5)$, the fit to SM fermion masses requires a singlet $S$, which leads to unviable embedding of NMSSM into $\mathrm{SU}(5)$ because such $S$ feeds singlet $N$ a mass of order unification scale as well. $ii)$, Similar result holds in the case of embedding NMSSM into $\mathrm{SO}(10)$, where $S$ is replaced by some Higgs fields responsible for $\mathrm{SO}(10)$ breaking. $iii)$, On the contrary, for the embedding of MSSM with $16$-dimensional vectorlike fermions into $\mathrm{SO}(10)$, the Higgs field responsible for the vectorlike mass of order TeV scale can evade those problems the singlet $N$ encounters because of an intermediate mass scale in the $126$-dimensional Higgs field.

   hep-phPRD(2019)·1 citation
9. 09*

   A Novel Approach to Neutrino-Hydrogen Measurements

   H. Duyang🇺🇸 · B. Guo🇺🇸 · S.R. Mishra🇺🇸 · R. Petti🇺🇸

   The limited statistics of the available (anti)neutrino-hydrogen (H) interactions has been a longstanding impediment for high-energy neutrino physics. We discuss a practical way to achieve accurate (anti)neutrino-hydrogen measurements, addressing the principal limitations of earlier experiments. Interactions on hydrogen are extracted by subtracting measurements on thin dedicated graphite (pure C) and polypropylene (CH${}_2$) targets within a highly segmented low-density detector. A kinematic selection is used to increase the purities to 80-95\% before subtraction. A statistics of $\mathcal{O}(10^6)$ can be realistically achieved in modern neutrino beams for the various $\nu (\bar{\nu })$-H event topologies. The availability of such samples would allow a precise determination of neutrino and antineutrino fluxes, as well as to directly constrain nuclear effects from a comparison with corresponding measurements on heavy materials within the same detector. The (anti)neutrino fluxes and the nuclear smearing are typically the leading sources of systematic uncertainties in long-baseline oscillation experiments. (Anti)neutrino-hydrogen interactions also provide an ideal tool for a wide range of precision tests of fundamental interactions.

   hep-phhep-exnucl-exnucl-th+1Eur.Phys.J.Plus(2024)·31 citations
10. 10*

    Implication of chiral symmetry for the heavy-light meson spectroscopy

    Meng-Lin Du🇩🇪

    Many hadronic states observed since 2003, especially for the positive-parity charm-strange states $D_{s0}^{\ast }(2317)$ and $D_{s1}(2460)$, do not conform with the conventional quark model expectations and raise various puzzles in charm meson spectroscopy. We demonstrate that those puzzles find a natural solution thanks to the recent development of chiral effective theory and Lattice simulations. The existence of the $D_{s0}^{\ast }(2317)$ and $D_{s1}(2460)$ are attributed to the nonperturbative dynamics of Goldstone bosons scattering off $D$ and $D^{\ast }$ mesons. It indicates that the lowest positive parity nonstrange scalar charm mesons, the $D_0^{\ast }(2400)$ in the Review of Particel Physics, should be replaced by two states. The well constructed amplitudes are fully in line with the high quality data on the decays $B^{-}\to D^{+}{\pi }^{-}{\pi }^{-}$ and $D_s^0\to {\bar{D}}^0{K}^{-}{\pi }^{+}$. This implies that the lowest positve-parity states are dynamically generated rather than conventional quark-antiquark states. This pattern has also been established for the scalar and axial-vector mesons made from light quarks ($u$, $d$ and $s$ quarks).

    hep-phhep-lat1 citation
11. 11*

    TMD gluon distributions for multiparton processes

    Marcin Bury🇵🇱 · Piotr Kotko🇵🇱 · Krzysztof Kutak🇵🇱

    We derive gauge invariant operators entering definitions of the Transverse Momentum Dependent (TMD) gluon distributions, for all five and six parton processes. Our calculations utilize color decomposition of amplitudes in the color flow basis. In addition, we find the general result for multi-gluon process (with arbitrary number of gluons) at large $N_c$. On phenomenological ground our results may be used for multi-jet production in the small-$x$ regime, where the TMD gluon distributions can be derived from the Color Glass Condensate effective theory.

    hep-phEPJC(2019)·22 citations
12. 12*

    Deciphering the coalescence behavior of Coulomb-Schrödinger atomic wave functions from an operator product expansion

    Yingsheng Huang🇨🇳 · Yu Jia🇨🇳 · Rui Yu🇨🇳

    We revisit the coalescence behavior of the atomic Schrödinger wave functions from the angle of an operator product expansion (OPE) within the nonrelativistic Coulomb-Schrödinger effective field theory. We take the electron-nucleus coalescence as an explicit example to demonstrate our formalism, where the celebrated Kato's cusp condition can be easily reproduced. An exact OPE relation is rigorously proved to all orders in perturbation theory. Our approach can be readily extended to ascertain the multi-particle coalescence behaviors of atomic wave functions, as well as to take relativistic effects into account.

    hep-phnucl-thphysics.atom-phphysics.chem-phPRA(2025)·3 citations
13. 13*

    A spin on same-sign W-boson pair production

    Sabrina Cotogno🇳🇱 · Tomas Kasemets🇩🇪 · Miroslav Myska🇨🇿

    We demonstrate that the LHC will be sensitive to quantum correlations between two quarks inside the proton. Same-sign W-boson pair production is the most promising channel for clear measurements of double parton scattering. The left-handed nature of the coupling between quarks and W-bosons makes it a prime probe to measure parton spin correlations. We perform a detailed analysis of double parton scattering, including relevant backgrounds. The analysis reveals that measurements comparing the rate at which two muons from W boson decays are produced in the same compared to opposite hemispheres are especially sensitive to spin correlations between two quarks inside the proton. We provide estimates of the significance of the measurements as a function of the integrated luminosity.

    hep-phhep-exPRD(2019)·27 citations
14. 14*

    Decoding (Pseudo)-Scalar Operators in Leptonic and Semileptonic $B$ Decays

    Giovanni Banelli🇳🇱 · Robert Fleischer🇳🇱 · Ruben Jaarsma🇳🇱 · Gilberto Tetlalmatzi-Xolocotzi🇳🇱

    We consider leptonic $B^{-}\to {\ell }^{-}{\bar{\nu }}_{\ell }$ and semileptonic $\bar{B}\to \pi {\ell }^{-}{\bar{\nu }}_{\ell }$, $\bar{B}\to \rho {\ell }^{-}{\bar{\nu }}_{\ell }$ decays and present a strategy to determine short-distance coefficients of New-Physics operators and the CKM element $|V_{ub}|$. As the leptonic channels play a central role, we illustrate this method for (pseudo)-scalar operators which may lift the helicity suppression of the corresponding transition amplitudes arising in the Standard Model. Utilising a new result by the Belle collaboration for the branching ratio of $B^{-}\to {\mu }^{-}{\bar{\nu }}_{\mu }$, we explore theoretically clean constraints and correlations between New Physics coefficients for leptonic final states with $\mu$ and $\tau$ leptons. In order to obtain stronger bounds and to extract $|V_{ub}|$, we employ semileptonic $\bar{B}\to \pi {\ell }^{-}{\bar{\nu }}_{\ell }$ and $\bar{B}\to \rho {\ell }^{-}{\bar{\nu }}_{\ell }$ decays as an additional ingredient, involving hadronic form factors which are determined through QCD sum rule and lattice calculations. In addition to a detailed analysis of the constraints on the New Physics contributions following from current data, we make predictions for yet unmeasured decay observables, compare them with experimental constraints and discuss the impact of CP-violating phases of the New-Physics coefficients.

    hep-phhep-exEPJC(2018)·25 citations
15. 15*

    Planar Two-Loop Five-Parton Amplitudes from Numerical Unitarity

    S. Abreu🇩🇪 · F. Febres Cordero🇩🇪 · H. Ita🇩🇪 · B. Page🇩🇪 · V. Sotnikov🇩🇪

    We compute a complete set of independent leading-color two-loop five-parton amplitudes in QCD. These constitute a fundamental ingredient for the next-to-next-to-leading order QCD corrections to three-jet production at hadron colliders. We show how to consistently consider helicity amplitudes with external fermions in dimensional regularization, allowing the application of a numerical variant of the unitarity approach. Amplitudes are computed by exploiting a decomposition of the integrand into master and surface terms that is independent of the parton type. Master integral coefficients are numerically computed in either finite-field or floating-point arithmetic and combined with known analytic master integrals. We recompute two-loop leading-color four-parton amplitudes as a check of our implementation. Results are presented for all independent four- and five-parton processes including contributions with massless closed fermion loops.

    hep-phhep-thJHEP(2018)·120 citations
16. 16*

    Further studies on the exclusive productions of $J/\psi +{\chi }_{cJ}$ ($J=0,1,2$) via $e^{+}{e}^{-}$ annihilation at the $B$ factories

    YingZhao Jiang🇨🇳 · Zhan Sun🇨🇳

    By including the interference effect between the QCD and the QED diagrams, we carry out a complete analysis on the exclusive productions of $e^{+}{e}^{-}\to J/\psi +{\chi }_{cJ}$ ($J=0,1,2$) at the $B$ factories with $\sqrt{s}=10.6$ GeV at the next-to-leading-order (NLO) level in ${\alpha }_s$, within the nonrelativistic QCD framework. It is found that the $\mathcal{O}({\alpha }^3{\alpha }_s)$-order terms that represent the tree-level interference are comparable with the usual NLO QCD corrections, especially for the ${\chi }_{c1}$ and ${\chi }_{c2}$ cases. To explore the effect of the higher-order terms, namely $\mathcal{O}({\alpha }^3{\alpha }_s^2)$, we perform the QCD corrections to these $\mathcal{O}({\alpha }^3{\alpha }_s)$-order terms for the first time, which are found to be able to significantly influence the $\mathcal{O}({\alpha }^3{\alpha }_s)$-order results. In particular, in the case of ${\chi }_{c1}$ and ${\chi }_{c2}$, the newly calculated $\mathcal{O}({\alpha }^3{\alpha }_s^2)$-order terms can to a large extent counteract the $\mathcal{O}({\alpha }^3{\alpha }_s)$ contributions, evidently indicating the indispensability of the corrections. In addition, we find that, as the collision energy rises, the percentage of the interference effect in the total cross section will increase rapidly, especially for the ${\chi }_{c1}$ case.

    hep-phEPJC(2018)·14 citations
17. 17*

    Late time supernova neutrino signal and proto-neutron star radius

    A. Gallo Rosso🇮🇹 · S. Abbar🇫🇷 · F. Vissani🇮🇹 · M.C. Volpe🇫🇷

    We discuss the possibility of reconstructing the newly formed proto-neutron star radius from the late time neutrino signal. A black-body emission is assumed for the neutron star cooling phase. We parametrize the neutrino time-integrated fluxes based on simulations of Roberts and Reddy. A likelihood analysis of the inverse-beta decay and elastic scattering events in Hyper-Kamiokande is performed in both three flavor and an effective one flavor scenario. We show that the precision achievable in the radius reconstruction strongly depends on a correlation with the pinching parameter and therefore the corresponding prior. Although this correlation hinders the precise measurement of the newly formed neutron star radius, it could help measure the pinching parameters with good accuracy in view of the current constraints on neutron star radius, or if the neutron star radius is precisely measured.

    hep-phJCAP(2018)·13 citations
18. 18*

    Dark matter shifts away from direct detection

    Reuven Balkin🇩🇪 · Maximilian Ruhdorfer🇩🇪 · Ennio Salvioni🇩🇪 · Andreas Weiler🇩🇪

    Dark matter could emerge along with the Higgs as a composite pseudo-Nambu-Goldstone boson $\chi$ with decay constant $f\sim \mathrm{TeV}$. This type of WIMP is especially compelling because its leading interaction with the Standard Model, the derivative Higgs portal, has the correct annihilation strength for thermal freeze-out if $m_{\chi }\sim O(100)$ GeV, but is negligible in direct detection experiments due to the very small momentum transfer. The explicit breaking of the shift symmetry which radiatively generates $m_{\chi }$, however, introduces non-derivative DM interactions. In existing realizations a marginal Higgs portal coupling $\lambda$ is generated with size comparable to the Higgs quartic, and thus well within reach of XENON1T. Here, we present and analyze the interesting case where the pattern of explicit symmetry breaking naturally suppresses $\lambda$ beyond the reach of current and future direct detection experiments. If the DM acquires mass from bottom quark loops, the bottom quark also mediates suppressed DM-nucleus scattering with cross sections that will be eventually probed by LZ. Alternatively, the DM can obtain mass from gauging its stabilizing $U(1)$ symmetry. No direct detection signal is expected even at future facilities, but the introduction of a dark photon ${\gamma }_D$ has a number of phenomenological implications which we study in detail, treating $m_{{\gamma }_D}$ as a free parameter. Complementary probes of the dark sector include indirect DM detection, DM self-interactions, and extra radiation, as well as collider experiments. We frame our discussion in an effective field theory, motivating our parameter choices with a detailed analysis of an $SO(7)/SO(6)$ composite Higgs model, which can yield either scenario at low energies.

    hep-phastro-ph.COJCAP(2018)·67 citations
19. 19*

    Leptophilic dark matter from gauged lepton number: Phenomenology and gravitational wave signatures

    Eric Madge🇩🇪 · Pedro Schwaller🇩🇪

    New gauge symmetries often appear in theories beyond the Standard Model. Here we study a model where lepton number is promoted to a gauge symmetry. Anomaly cancellation requires the introduction of additional leptons, the lightest of which is a natural leptophilic dark matter candidate. We perform a comprehensive study of both collider and dark matter phenomenology. Furthermore we find that the model exhibits a first order lepton number breaking phase transition in large regions of parameter space. The corresponding gravitational wave signal is computed, and its detectability at LISA and other future GW detectors assessed. Finally we comment on the complementarity of dark matter, collider and gravitational wave observables, and on the potential reach of future colliders.

    hep-phastro-ph.COhep-exJHEP(2019)·66 citations
20. 20*

    The phenomenology of electric dipole moments in models of scalar leptoquarks

    W. Dekens🇺🇸 · J. de Vries🇺🇸 · M. Jung🇩🇪 · K.K. Vos🇩🇪

    We study the phenomenology of electric dipole moments (EDMs) induced in various scalar leptoquark models. We consider generic leptoquark couplings to quarks and leptons and match to Standard Model effective field theory. After evolving the resulting operators to low energies, we connect to EDM experiments by using up-to-date hadronic, nuclear, and atomic matrix elements. We show that current experimental limits set strong constraints on the possible CP-violating phases in leptoquark models. Depending on the quarks and leptons involved in the interaction, the existing searches for EDMs of leptons, nucleons, atoms, and molecules all play a role in constraining the CP-violating couplings. We discuss the impact of hadronic and nuclear uncertainties as well as the sensitivities that can be achieved with future EDM experiments. Finally, we study the impact of EDM constraints on a specific leptoquark model that can explain the recent $B$-physics anomalies.

    hep-phJHEP(2019)·138 citations
21. 21*

    Low Scale Left-Right Symmetry and Naturally Small Neutrino Mass

    Vedran Brdar🇩🇪 · Alexei Yu. Smirnov🇩🇪

    We consider the low scale ($10$ - $100$ TeV) left-right symmetric model with "naturally" small neutrino masses generated through the inverse seesaw mechanism. The Dirac neutrino mass terms are taken to be similar to the masses of charged leptons and quarks in order to satisfy the quark-lepton similarity condition. The inverse seesaw implies the existence of fermion singlets $S$ with Majorana mass terms as well as the "left" and "right" Higgs doublets. These doublets provide the portal for $S$ and break the left-right symmetry. The inverse seesaw allows to realize a scenario in which the large lepton mixing originates from the Majorana mass matrix of $S$ fields which has certain symmetry. The model contains heavy pseudo-Dirac fermions, formed by $S$ and the right-handed neutrinos, which have masses in the $1$ GeV - $100$ TeV range and can be searched for at current and future colliders such as LHC and FCC-ee as well as in SHiP and DUNE experiments. Their contribution to neutrinoless double beta decay is unobservable. The radiative corrections to the mass of the Higgs boson and the possibility for generating the baryon asymmetry of the Universe are discussed. Modification of the model with two singlets ($S_L$ and $S_R$) per generation can provide a viable keV-scale dark matter candidate.

    hep-phJHEP(2019)·30 citations
22. 22*

    Dark Matter from Strong Dynamics: The Minimal Theory of Dark Baryons

    Anthony Francis🇨🇭 · Renwick J. Hudspith🇨🇦 · Randy Lewis🇨🇦 · Sean Tulin🇨🇦

    As a simple model for dark matter, we propose a QCD-like theory based on $\mathrm{SU}(2)$ gauge theory with one flavor of dark quark. The model is confining at low energy and we use lattice simulations to investigate the properties of the lowest-lying hadrons. Compared to QCD, the theory has several peculiar differences: there are no Goldstone bosons or chiral symmetry restoration when the dark quark becomes massless; the usual global baryon number symmetry is enlarged to $\mathrm{SU}(2{)}_{\mathrm{B}}$, resembling isospin; and baryons and mesons are unified together in $\mathrm{SU}(2{)}_{\mathrm{B}}$ iso-multiplets. We argue that the lightest baryon, a vector boson, is a stable dark matter candidate and is a composite realization of the hidden vector dark matter scenario. The model naturally includes a lighter state, the analog of the ${\eta }^{\prime }$ in QCD, for dark matter to annihilate into to set the relic density via thermal freeze-out. Dark matter baryons may also be asymmetric, strongly self-interacting, or have their relic density set via $3\to 2$ cannibalizing transitions. We discuss some experimental implications of coupling dark baryons to the Higgs portal.

    hep-phhep-latJHEP(2018)·60 citations
23. 23*

    Induced resonance makes light sterile neutrino Dark Matter cool

    F. Bezrukov🇬🇧 · A. Chudaykin🇷🇺 · D. Gorbunov🇷🇺

    We describe two new generation mechanisms for Dark Matter composed of sterile neutrinos with $\mathcal{O}(1)$ keV mass. The model contains a light scalar field which coherently oscillates in the early Universe and modulates the Majorana mass of the sterile neutrino. In a region of model parameter space, the oscillations between active and sterile neutrinos are resonantly enhanced. This mechanism allows us to produce sterile neutrino DM with small mixing angle with active neutrinos, thus evading the X-ray constraints. At the same time the spectrum of produced DM is much cooler, than in the case of ordinary oscillations in plasma, opening a window of lower mass DM, which is otherwise forbidden by structure formation considerations. In other regions of the model parameter space, where the resonance does not appear, another mechanism can operate: large field suppresses the active-sterile oscillations, but instead sterile neutrinos are produced by the oscillating scalar field when the effective fermion mass crosses zero. In this case DM component is cold, and even 1 keV neutrino is consistent with the cosmic structure formation.

    hep-phastro-ph.COhep-exPRD(2019)·14 citations
24. 24*

    P-wave heavy quarkonium spectrum with next-to-next-to-next-to-leading logarithmic accuracy

    Clara Peset🇩🇪 · Antonio Pineda🇪🇸 · Jorge Segovia🇪🇸

    We compute the heavy quarkonium mass of $l\ne 0$ (angular momentum) states, with otherwise arbitrary quantum numbers, with next-next-to-next-to-leading logarithmic (N${}^3$LL) accuracy. This constitutes the first observable in heavy quarkonium for which two orders of the weak-coupling expansion sensitive to the ultrasoft scale are known and the resummation of ultrasoft logarithms is made. We also obtain, for the first time, resummed N${}^3$LL expressions for the different fine and hyperfine energy splittings of these states, which are not sensitive to the ultrasoft scale but still require resummation of (hard) logarithms. We do this analysis for the equal and non-equal mass cases. We also study an alternative computational scheme that treats the static potential exactly. We then perform a comprehensive phenomenological analysis: we apply these results to the $n=2$, $l=1$ bottomonium, $B_c$ and charmonium systems and study their convergence.

    hep-phhep-latnucl-thPRD(2018)·26 citations
25. 25*

    Universal Relations in Composite Higgs Models

    Da Liu🇺🇸 · Ian Low🇺🇸 · Zhewei Yin🇺🇸

    We initiate a phenomenological study of `universal relations' in composite Higgs models, which are dictated by nonlinear shift symmetries acting on the 125 GeV Higgs boson. These are relations among one Higgs couplings with two electroweak gauge bosons (HVV), two Higgses couplings with two electroweak gauge bosons (HHVV), one Higgs couplings with three electroweak gauge bosons (HVVV), as well as triple gauge boson couplings (TGC), which are all controlled by a single input parameter: the decay constant $f$ of the pseudo-Nambu-Goldstone Higgs boson. Assuming custodial invariance in strong sector, the relation is independent of the symmetry breaking pattern in the UV, for an arbitrary symmetric coset $G/H$. The complete list of corrections to HVV, HHVV, HVVV and TGC couplings in composite Higgs models is presented to all orders in $1/f$, and up to four-derivative level, without referring to a particular $G/H$. We then present several examples of universal relations in ratios of coefficients which could be extracted experimentally. Measuring the universal relation requires a precision sensitive to effects of dimension-8 operators in the effective Lagrangian and highlights the importance of verifying the tensor structure of HHVV interactions in the standard model, which remains untested to date.

    hep-phhep-exJHEP(2019)·30 citations
26. 26*

    Searching for the $W\gamma$ decay of a charged Higgs boson

    Heather E. Logan🇨🇦 · Yongcheng Wu🇨🇦

    We study the prospects for charged Higgs boson searches in the $W\gamma$ decay channel. This loop-induced decay channel can be important if the charged Higgs is fermiophobic, particularly when its mass is below the $WZ$ threshold. We identify useful kinematic observables and evaluate the future Large Hadron Collider sensitivity to this channel using the custodial-fiveplet charged Higgs in the Georgi-Machacek model as a fermiophobic benchmark. We show that the LHC with 300~fb${}^{-1}$ of data at 14~TeV will be able to exclude charged Higgs masses below about 130~GeV for almost any value of the SU(2)${}_L$-triplet vacuum expectation value in the model, and masses up to 200~GeV and beyond when the triplet vacuum expectation value is very small. We describe the signal simulation tools created for this analysis, which have been made publicly available.

    hep-phJHEP(2018)·25 citations
27. 27*

    Constraints on Lorentz Invariance and CPT Violation using Optical Photometry and Polarimetry of Active Galaxies BL Lacertae and S5 B0716+714

    Andrew S. Friedman🇺🇸 · David Leon🇺🇸 · Kevin D. Crowley🇺🇸 · Delwin Johnson🇺🇸 · Grant Teply🇺🇸 · David Tytler🇺🇸 · Brian G. Keating🇺🇸 · Gary M. Cole

    Various quantum gravity approaches that extend beyond the standard model predict Lorentz Invariance and Charge-Parity-Time Violation at energies approaching the Planck scale. These models frequently predict a wavelength dependent speed of light, which would result in time delays between promptly emitted photons at different energies, as well as a wavelength-dependent rotation of the plane of linear polarization for photons resulting from vacuum birefringence. Here, we describe a pilot program with an automated system of small telescopes that can simultaneously conduct high cadence optical photometry and polarimetry of Active Galactic Nuclei (AGN) in multiple passbands. We use these observations as a proof-of-principle to demonstrate how such data can be used to test various Lorentz Violation models, including special cases of the Standard Model Extension (SME). In our initial campaign with this system, the Array Photo Polarimeter, we observed two AGN sources, including BL Lacertae at redshift z = 0.069, and S5 B0716+714 at z = 0.31. We demonstrate that optical polarimetry with a broadband Luminance filter combined with simultaneous $I_c$-band observations yields SME parameter constraints that are up to ~10 and ~30 times more sensitive than with a standard $I_c$-band filter, for SME models with mass dimension d = 5 and d = 6, respectively. Using only a small system of telescopes with an effective 0.45-m aperture, we further demonstrate d = 5 constraints for individual lines of sight that are within a factor of ~1-10 in sensitivity to comparable constraints from optical polarimetry with a 3.6-m telescope. Such an approach could significantly improve existing SME constraints via a polarimetric all-sky survey of AGN with multiple 1-meter class telescopes.

    ↳ astro-ph.HEgr-qchep-phPRD(2019)·27 citations
28. 28*

    Charged-current scattering off ${}^{16}$O nucleus as a detection channel for supernova neutrinos

    Ken'ichiro Nakazato🇯🇵 · Toshio Suzuki🇯🇵 · Makoto Sakuda🇯🇵

    Event spectra of the neutrino-${}^{16}$O charged-current reactions in Super-Kamiokande are evaluated for a future supernova neutrino burst. Since these channels are expected to be useful for diagnosing a neutrino spectrum with high average energy, the evaluations are performed not only for an ordinary supernova neutrino model but also for a model of neutrino emission from a black-hole-forming collapse. Using shell model results, whose excitation energies are consistent with the experimental data, the cross sections of the ${}^{16}$O(${\nu }_e,e^{-}$)X and ${}^{16}$O(${\bar{\nu }}_e,e^{+}$)X reactions for each nuclear state with a different excitation energy are employed in this study. It is found that, owing to the components of the reaction with higher excitation energy, the event spectrum becomes 4-7 MeV softer than that in the case without considering the excitation energies. In addition, a simplified approach to evaluate the event spectra is proposed for convenience and its validity is examined.

    ↳ astro-ph.HEhep-phnucl-thPTEP(2018)·22 citations
29. 29*

    Dark energy in Horndeski theories after GW170817: A review

    Ryotaro Kase🇯🇵 · Shinji Tsujikawa🇯🇵

    The gravitational-wave event GW170817 from a binary neutron star merger together with the electromagnetic counterpart showed that the speed of gravitational waves $c_t$ is very close to that of light for the redshift $z<0.009$. This places tight constraints on dark energy models constructed in the framework of modified gravitational theories. We review models of the late-time cosmic acceleration in scalar-tensor theories with second-order equations of motion (dubbed Horndeski theories) by paying particular attention to the evolution of dark energy equation of state and observables relevant to the cosmic growth history. We provide a gauge-ready formulation of scalar perturbations in full Horndeski theories and estimate observables associated with the evolution of large-scale structures, cosmic microwave background, and weak lensing by employing a so-called quasi-static approximation for the modes deep inside the sound horizon. In light of the recent observational bound of $c_t$, we also classify surviving dark energy models into four classes depending on different structure-formation patterns and discuss how they can be observationally distinguished from each other. In particular, the nonminimally coupled theories in which the scalar field $\varphi$ has a coupling with the Ricci scalar $R$ of the form $G_4(\varphi )R$, including $f(R)$ gravity, can be tightly constrained not only from the cosmic expansion and growth histories but also from the variation of screened gravitational couplings. The cross correlation of integrated Sachs-Wolfe signal with galaxy distributions can be a key observable for placing bounds on the relative ratio of cubic Galileon density to total dark energy density. The dawn of gravitational-wave astronomy will open up a new window to constrain nonminimally coupled theories further by the modified luminosity distance of tensor perturbations.

    ↳ gr-qcastro-ph.COhep-phhep-thInt.J.Mod.Phys.D(2019)·266 citations
30. 30*

    Entropy methods for CMB analysis of anisotropy and non-Gaussianity

    Momchil Minkov🇺🇸 · Marvin Pinkwart🇩🇪 · Peter Schupp🇩🇪

    We propose several pseudoentropy measures that agree well with the Wehrl entropy, but are significantly faster to compute. All of them are rotationally invariant measures of entanglement very sensitive to non-Gaussianity, anisotropy, and statistical dependence of spherical harmonic coefficients. We provide a simple proof that the projection pseudoentropy converges to the Wehrl entropy with increasing dimensionality of the ancilla projection space. Furthermore, for $l=2$, we show that both the Wehrl entropy and the angular pseudoentropy can be expressed as functions of the squared chordal distance of multipole vectors. We also show that the angular pseudoentropy can distinguish between Gaussian and non-Gaussian temperature fluctuations at large multipoles and henceforth provides a non-brute-force method for identifying non-Gaussianities. This allows us to study possible hints of statistical anisotropy and non-Gaussianity in the CMB up to multipole $l=1000$ using Planck 2015/2018, and WMAP 7-yr data. We find that $l=5$ and $28$ have a large entropy at $2$--$3\sigma$ significance and a slight hint towards a connection of this with the cosmic dipole. On a wider range of large angular scales we do not find indications of isotropy/Gaussianity violation. We also find a small-scale range, $l\in [895,905]$, that is incompatible with the assumptions at about $3\sigma$ level, although how much this significance can be reduced by taking into account the selection effect is left as an open question. We find overall similar results in our analysis of the 2015 and the 2018 data. Finally, we also demonstrate how a range of angular momenta can be studied with the range angular pseudoentropy. Our main purpose is to introduce the methods, analyze their mathematical background, and demonstrate their usage for providing researchers in this field with an additional tool.

    ↳ astro-ph.COhep-phquant-phPRD(2019)·8 citations
31. 31*

    Can Holographic dark energy models fit the observational data?

    Mohammad Malekjani🇮🇷 · Mehdi Rezaei🇮🇷 · Iman A. Akhlaghi🇮🇷

    In this work we investigate the holographic dark energy models with slowly time-varying model parameter defined based on the current Hubble horizon length scale. While the previous studies on the three popular holographic dark energy models defined based on the future event horizon, Ricci scale and Granda-Oliveros IR cutoffs showed that these models cannot fit the observational data [1], in this work we show that the holographic dark energy models with time-varying model parameter defined on the current Hubble radius are well favored by observations. Using the standard ${\chi }^2$ minimization in the context of Markov Chain Monte Carlo method, we compare the ability of holographic dark energy models with time-varying $c^2$ parameter constructed on the current Hubble length scale against different sets of observational data namely expansion data, growth rate data and expansion+growth rate data respectively. Based on the values of Akaike and Bayesian information criteria, we find that these types of holographic dark energy models are well fitted to both expansion and growth rate observations as equal to $\Lambda$CDM cosmology. We also put constraints on the cosmological parameters and show that the transition epoch form early decelerated to current accelerated expansion calculated in holographic dark energy models with time-varying model parameter defined on the Hubble length is consistent with observations.

    ↳ gr-qcastro-ph.COhep-phPRD(2018)·40 citations
32. 32*

    $\bar{K}\bar{D}N$ molecular state as a "$uuds\bar{c}$ pentaquark" in a three-body calculation

    Junko Yamagata-Sekihara🇯🇵 · Takayasu Sekihara🇯🇵

    We predict a new three-body hadronic molecule composed of antikaon $\bar{K}$, anticharm meson $\bar{D}$, and nucleon $N$ with spin/parity $J^P=1/2^{+}$ and isospin $I=1/2$. This state behaves like an explicit pentaquark state because its minimal quark configuration is $uuds\bar{c}$ or $udds\bar{c}$. Owing to the attraction between every pair of two hadrons, in particular the $\bar{K}\bar{D}$ attraction which dynamically generates $D_{s0}(2317{)}^{-}$ and $\bar{K}N$ attraction which dynamically generates $\Lambda (1405)$, the $\bar{K}\bar{D}N$ system is bound, and its eigenenergy is calculated as $3244-17i$ MeV in a nonrelativistic three-body potential model. We discuss properties of this $\bar{K}\bar{D}N$ quasibound state which emerge uniquely in three-body dynamics.

    ↳ nucl-thhep-phnucl-exPRC(2019)·4 citations
33. 33*

    4d models of dS uplift in KKLT

    Renata Kallosh🇺🇸 · Andrei Linde🇺🇸 · Evan McDonough🇺🇸 · Marco Scalisi🇧🇪

    It was shown in arXiv:1808.09428 that the modified 4d version of the KKLT model proposed in arXiv:1707.08678 is inconsistent for large values of the parameter $c$ advocated in arXiv:1707.08678, since there is a point in the moduli space where $|D_{S}W{|}^2$ vanishes. The authors responded with yet another modification of the 4d KKLT model arXiv:1809.06618. However, for large $c$, this model suffers from an even worse problem: not only is there a point in the moduli space where $|D_{S}W{|}^2$ vanishes, there is also a region in the moduli space where $|D_{S}W{|}^2$ is negative. Meanwhile for small $c$ these models have dS vacua. We construct improved models, which are fully consistent for all values of parameters, just as the original version of the KKLT model using a nilpotent superfield. These models have a family of dS vacua for a broad range of parameter values. Thus, the results of the analysis of all presently available consistent generalizations of the 4d KKLT model, in the domain of their validity, confirm the existence of dS vacua in the KKLT scenario.

    ↳ hep-thgr-qchep-phPRD(2019)·47 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.