Thu·Sep 27, 2018Thursday·September 27, 2018

1. 01*

   Effective Field Theory Amplitudes the On-Shell Way: Scalar and Vector Couplings to Gluons

   Yael Shadmi🇮🇱 · Yaniv Weiss🇮🇱

   We use on-shell methods to calculate tree-level effective field theory (EFT) amplitudes, with no reference to the EFT operators. Lorentz symmetry, unitarity and Bose statistics determine the allowed kinematical structures. As a by-product, the number of independent EFT operators simply follows from the set of polynomials in the Mandelstam invariants, subject to kinematical constraints. We demonstrate this approach by calculating several amplitudes with a massive, SM-singlet, scalar ($h$) or vector ($Z^{\prime }$) particle coupled to gluons. Specifically, we calculate $hggg$, $hhgg$ and $Z^{\prime }ggg$ amplitudes, which are relevant for the LHC production and three-gluon decays of the massive particle. We then use the results to derive the massless-$Z^{\prime }$ amplitudes, and show how the massive amplitudes decompose into the massless-vector plus scalar amplitudes. Amplitudes with the gluons replaced by photons are straightforwardly obtained from the above.

   hep-phhep-thJHEP(2019)·119 citations
2. 02*

   Composite Higgs Models with a Hidden Sector

   Ann Nelson🇺🇸 · Michael Park🇺🇸 · Devin Walker🇺🇸

   We discuss the phenomenology of composite Higgs models that naturally produce a Standard Model-like Higgs boson with a mass of $126$ GeV. The effective theory below the compositeness scale is weakly coupled in these models, and the goldstone sector acts as a portal between the third generation of quarks and a hidden gauge sector. The addition of hidden-sector fermions gives rise to a calculable effective scalar potential with a naturally light scalar resonance. The generic prediction of these theories is the existence of additional pseudo-Nambu Goldstone bosons with electroweak-scale cross sections and masses. In this paper we analyze the collider signatures for some simple concrete realizations of this framework. We find that despite the existence of additional weakly and strongly coupled particles that are kinematically within reach of current experiments, the generic signatures are difficult to resolve at the LHC, and could remain well-hidden in the absence of an $e^{+}{e}^{-}$ Higgs factory such as the CEPC or a surface detector such as MATHUSLA.

   hep-phPRD(2019)·4 citations
3. 03*

   Inspiration from Intersecting D-branes: General Supersymmetry Breaking Soft Terms in No-Scale $\mathcal{F}$-$SU(5)$

   Ron De Benedetti🇺🇸 · Chuang Li🇨🇳 · Tianjun Li🇨🇳 · Adam Lux🇨🇳 · James A. Maxin🇺🇸 · Dimitri V. Nanopoulos🇺🇸

   Motivated by D-brane model building, we evaluate the $\mathcal{F}$-$SU(5)$ model with additional vector-like particle multiplets, referred to as flippons, within the framework of No-Scale Supergravity with non-vanishing general supersymmetry breaking soft terms at the string scale. The viable phenomenology is uncovered by applying all current experimental constraints, including but not limited to the correct light Higgs boson mass, WMAP and Planck relic density measurements, and several LHC constraints on supersymmetric particle spectra. Four interesting regions of the parameter space arise, as well as mixed scenarios, given by: (i) light stop coannihilation; (ii) pure Higgsino dark matter; (iii) Higgs funnel; and (iv) light stau coannihilation. All regions can generate the observed value of the relic density commensurate with a 125 GeV light Higgs boson mass, with the exception of the relatively small relic density value for the pure Higgsino lightest supersymmetric particle (LSP). This work is concluded by gauging the model against present LHC search constraints and derivation of the final states observable at the LHC for each of these scenarios.

   hep-phEPJC(2018)·4 citations
4. 04*

   Many-Body Neutrino-Exchange Interactions and Neutrino Mass: Comment on Phys. Rev. Lett. 120, 223202 (2018)

   E. Fischbach🇺🇸

   This Comment corrects an erroneous remark by Stadnik in a recent paper to the effect that many-body neutrino-mediated forces are suppressed in all types of stars.

   hep-ph3 citations
5. 05*

   Effective Field Theory in the top sector: do multijets help?

   Christoph Englert🇬🇧 · Michael Russell🇩🇪 · Chris D. White🇬🇧

   Many studies of possible new physics employ effective field theory (EFT), whereby corrections to the Standard Model take the form of higher-dimensional operators, suppressed by a large energy scale. Fits of such a theory to data typically use parton level observables, which limits the datasets one can use. In order to theoretically model search channels involving many additional jets, it is important to include tree-level matrix elements matched to a parton shower algorithm, and a suitable matching procedure to remove the double counting of additional radiation. There are then two potential problems: (i) EFT corrections are absent in the shower, leading to an extra source of discontinuities in the matching procedure; (ii) the uncertainty in the matching procedure may be such that no additional constraints are obtained from observables sensitive to radiation. In this paper, we review why the first of these is not a problem in practice, and perform a detailed study of the second. In particular, we quantify the additional constraints on EFT expected from top pair plus multijet events, relative to inclusive top pair production alone.

   hep-phhep-exPRD(2019)·20 citations
6. 06*

   Quasi-two-body decays $B_{(s)}\to K^{\ast }(892)h\to K\pi h$ in perturbative QCD approach

   Ya Li🇨🇳 · Wen-Fei Wang🇨🇳 · Ai-Jun Ma🇨🇳 · Zhen-Jun Xiao🇨🇳

   We extend our recent works on the $P$-wave two-pion resonant contributions to the kaon-pion cases in the hadronic charmless $B$ meson decays by employing the perturbative QCD approach. The concerned decay modes are analysed in the quasi-two-body framework by parameterizing the kaon-pion distribution amplitude ${\Phi }_{K\pi }^{\mathrm{P}}$, which contains the final state interactions between the kaon and pion in the resonant region. The relativistic Breit-Wigner formula for the $P$-wave resonant state $K^{\ast }(892)$ is adopted to parameterize the time-like form factor $F_{K\pi }$. We calculate the $CP$-averaged branching ratios and direct $CP$-violating asymmetries of the quasi-two-body decays $B_{(s)}\to K^{\ast }(892)h\to K\pi h$, with $h=(\pi ,K)$, in this work. It is shown that the agreement of theoretical results with the experimental data can be achieved, through which Gegenbauer moments of the $P$-wave kaon-pion distribution amplitudes are determined. The predictions in this work will be tested by the precise data from the LHCb and the future Belle II experiments.

   hep-phhep-exEPJC(2019)·39 citations
7. 07*

   Comment on energy dependence of the slope parameter

   S.M. Troshin🇷🇺 · N.E. Tyurin🇷🇺

   We discuss energy dependence of the slope parameter in elastic proton scattering. It is shown that unitarity generates energy dependence of the slope parameter in geometrical models consistent with the experimental results including recent LHC data.

   hep-phEPL(2018)·5 citations
8. 08*

   Gravitational Waves from Phase Transitions in Models with Charged Singlets

   Amine Ahriche🇩🇿 · Katsuya Hashino🇯🇵 · Shinya Kanemura🇯🇵 · Salah Nasri🇦🇪

   We investigate the effect of extra singlets on the electroweak phase transition (EWPT) strength and the spectrum of the corresponding gravitational waves (GWs). We consider here the standard model (SM) extended with a singlet scalar with multiplicity N coupled to the SM Higgs doublet. After imposing all the theoretical and experimental constraints and defining the region where the EWPT is strongly first order, we obtain the region in which the GWs spectrum can be reached by different future experiments such as LISA and DECIGO.

   hep-phastro-ph.HEPLB(2019)·49 citations
9. 09*

   Study of coherence and mixedness in meson and neutrino systems

   Khushboo Dixit🇮🇳 · Javid Naikoo🇮🇳 · Subhashish Banerjee🇮🇳 · Ashutosh Kumar Alok🇮🇳

   We study the interplay between coherence and mixedness in meson and neutrino systems. The dynamics of the meson system is treated using the open quantum system approach taking into account the decaying nature of the system. Neutrino dynamics is studied in the context of three flavor oscillations within the framework of a decoherence model recently used in the context of LSND (Liquid Scintillator Neutrino Detector) experiment. For meson systems, the decoherence effect is negligible in the limit of zero CP violation. Interestingly, the average mixedness increases with time for about one lifetime of these particles. For neutrino system, in the context of the model considered, the decoherence effect is maximum for neutrino energy around 30 MeV. Further, the effect of CP violating phase is found to decrease (increase) the coherence in the upper $0<\delta <\pi$ (lower $\pi <\delta <2\pi$) half plane.

   hep-phEPJC(2019)·57 citations
10. 10*

    Scale setting in inclusive jet production at hadron colliders

    Joao Pires🇵🇹

    In this contribution we review the status of inclusive jet cross sections at hadron colliders in perturbative QCD, studying in particular the renormalisation and factorisation scale dependence of the one-jet inclusive cross section at NNLO.

    hep-phhep-exPoS(2018)·0 citations
11. 11*

    Enhanced diHiggs signal from hidden scalar QCD at leading-order scale-symmetry limit

    Ruiwen Ouyang🇨🇳 · Shinya Matsuzaki🇨🇳

    We develop an effective-model description arising from a recently proposed scale-invariant hidden scalar-QCD, which has been used to explain the dynamical origin of the electroweak scale. In addition to the previous works, our new effective model includes the dynamical scale-anomaly effect from the hidden QCD gluons, to explicitly break the classical-scale invariance at the level of an effective field theory, which is known as the leading-order scale-symmetry (LOSS). In the phenomenological analysis, the proposed model predicts a light composite dilaton composed of hidden scalar quarks and gluons with the mass around electroweak scale (around 280 GeV), and has only one input parameter, which is the mixing angle between the Higgs boson and the composite dilaton. Our result for the dilaton mass is in accord with the lattice simulation for scalar QCD, where the scalar-quark bound states acquire a large effective mass from the hidden gluon contribution. Furthermore, we predict several significant deviations from the SM, like the diHiggs production cross sections (maximally about 10 times larger than the SM prediction), that could be directly tested at the high luminosity LHC. It is also the first study for the diHiggs production signal predicted from a scale(conformal)-invariant hidden sector, even from dark/hidden QCD. Our proposed effective model is thus significantly different than the conventional realization of scale-invariant hidden-scalar QCD without the scale anomaly effect, and can potentially provide a competitive explanation for many exotic phenomena beyond the standard model, such as new dark matter candidates and a strongly first-order electroweak phase transition.

    hep-phPRD(2019)·3 citations
12. 12*

    Future strategies for the discovery and the precise measurement of the Higgs self coupling

    Alain Blondel🇨🇭 · Patrick Janot🇨🇭

    The European Strategy for Particle Physics (ESSP) submitted in 2013 a deliberation document to the CERN council explaining that a lepton collider with "energies of 500\,GeV or higher could explore the Higgs properties further, for example the [Yukawa] coupling to the top quark, the [trilinear] self-coupling and the total width.". In view of the forthcoming ESPP update in 2020, variations on this qualitative theme have been applied, inaccurately, to the case of the ILC, to argue that an upgrade to 500\,GeV would allow the measurement of the Higgs potential and would increase the potential for new particle searches. As a consequence, the strategic question was raised again whether the FCC-ee design study ought to consider a 500 GeV energy upgrade. In this note, we revisit the ESSP 2013 statement quantitatively and find [...] that 500 GeV is not a particularly useful energy for the lepton colliders under consideration, especially for the FCC-ee. A 5 sigma demonstration of the existence of the Higgs self-coupling is within reach at the energies foreseen for the FCC-ee, with a moderate change of configuration, which certainly deserves consideration.

    hep-ph31 citations
13. 13*

    Dissociation of Quarkonium in hot and Dense Media in an Anisotropic Plasma in the Non-Relativistic Quark Model

    M. Abu-Shady🇪🇬 · H. M. Mansour🇪🇬 · A. I. Ahmadov🇦🇿

    In this paper, quarkonium dissociation is investigated in an anisotropic plasma in the hot and dense media. For that purpose, the multidimensional Schrodinger equation is solved analytically by Nikiforov-Uvarov (NU) method for the real part of the potential in an anisotropic medium. The binding energy and dissociation temperature are calculated. In comparison with an isotropic medium, the binding energy of quarkonium is enhanced in the presence of an anisotropic medium. The present results show that the dissociation temperature increases with increasing anisotropic parameter for 1S state of the charmonium and bottomonium. We observe that the lower baryonic chemical potential has small effect in both isotropic and anisotropic media. A comparison is presented with other pervious theoretical works.

    hep-phAdv.High Energy Phys.(2019)·22 citations
14. 14*

    Doubly heavy baryons at LHC

    A. V. Berezhnoy🇷🇺 · A. K. Likhoded🇷🇺 · A. V. Luchinsky🇷🇺

    The theoretical analysis of production, lifetime, and decays of doubly heavy baryons is presented. The lifetime of ${\Xi }_{cc}^{++}$ baryon recently measured by the LHCb Collaboration is used to estimate the lifetimes of other doubly heavy baryons. The production and the possibility of observation of ${\Xi }_{bc}$ baryon at LHC are discussed.

    hep-phPRD(2018)·64 citations
15. 15*

    Vacuum stability in stau-neutralino coannihilation in MSSM

    Guang Hua Duan🇨🇳 · Chengcheng Han🇯🇵 · Bo Peng🇨🇳 · Lei Wu🇨🇳 · Jin Min Yang🇨🇳

    The stau-neutralino coannihilation provides a feasible way to accommodate the observed cosmological dark matter (DM) relic density in the minimal supersymmetric standard model (MSSM). In such a coannihilation mechanism the stau mass usually has an upper bound since its annihilation rate becomes small with the increase of DM mass. Inspired by this observation, we examine the upper limit of stau mass in the parameter space with a large mixing of staus. We find that the stau pair may dominantly annihilate into dibosons and hence the upper bound on the stau mass ($\sim 400$ GeV) obtained from the $f\bar{f}$ final states can be relaxed. Imposing the DM relic density constraint and requiring a long lifetime of the present vacuum, we find that the lighter stau mass can be as heavy as about 1.4 TeV for the stau maximum mixing. However, if requiring the present vacuum to survive during the thermal history of the universe, this mass limit will reduce to about 0.9 TeV. We also discuss the complementarity of vacuum stability and direct detections in probing this stau coannihilation scenario.

    hep-phPLB(2019)·16 citations
16. 16*

    Inhomogeneous chiral phases away from the chiral limit

    Michael Buballa🇩🇪 · Stefano Carignano🇪🇸

    The effect of explicit chiral-symmetry breaking on inhomogeneous chiral phases is studied within a Nambu-Jona-Lasinio model with nonzero current quark mass. Generalizing an earlier result obtained in the chiral limit, we show within a Ginzburg-Landau analysis that the critical endpoint of the first-order chiral phase boundary between two homogeneous phases gets replaced by a "pseudo-Lifshitz point" when the possibility of inhomogeneous order parameters is considered. Performing a stability analysis we also show that the unstable mode along the phase boundary is in the scalar but not in the pseudoscalar channel, suggesting that modulations which contain pseudoscalar condensates, like a generalized dual chiral density wave, are disfavored against purely scalar ones. Numerically we find that the inhomogeneous phase shrinks as one moves away from the chiral limit, but survives even at significantly large values of the current quark mass.

    hep-phnucl-thPLB(2019)·50 citations
17. 17*

    Multiplicity Dependence of the Jet Structures in pp Collisions at LHC Energies

    Zoltán Varga🇭🇺 · Róbert Vértesi🇭🇺 · Gergely Gábor Barnaföldi🇭🇺

    We study the event multiplicity dependence of the jet structure in pp collisions. We present evidence for jet shape modification due to multi-parton interactions using PYTHIA and HIJING++ Monte Carlo (MC) event generators as an input to our analysis. We introduce a characteristic jet size measure which is independent of the choice of the simulation parameters, parton distribution functions, jet reconstruction algorithms and even of the presence or absence of multi-parton interactions. We also investigate heavy-flavor jets and show the sensitivity of the multiplicity-differential jet structure to flavor-dependent fragmentation.

    hep-phMDPI Proc.(2019)·3 citations
18. 18*

    Determination of the quark mass ratio $Q$ from $\eta \to 3\pi$

    Stefan Lanz🇨🇭

    The decay $\eta \to 3\pi$ proceeds exclusively through isospin violating operators and is therefore an excellent probe to examine the strength of isospin breaking in the strong interaction. The latter can be expressed through the quark mass ratio $Q^2=(m_s^2-{\hat{m}}^2)/(m_d^2-m_u^2)$. The main object of this thesis is to analyse the decay $\eta \to 3\pi$ using dispersion relations in order to extract $Q$ as well as other physical quantities. The dispersion relations are a set of integral equations that lead to a representation of the decay amplitude in terms of four unknown subtraction constants. We apply two different methods to determine these. Following the procedure of Anisovich and Leutwyler, we match our dispersive representation to the one-loop result from chiral perturbation theory, thus updating their old analysis. In addition, we also make use of the recent experimental determination of the Dalitz distribution by the KLOE collaboration to obtain information on the subtraction constants. In this way we find $Q=21.31_{-0.50}^{+0.59}$.

    hep-ph7 citations
19. 19*

    Interplay of super-WIMP and freeze-in production of dark matter

    Mathias Garny🇩🇪 · Jan Heisig🇩🇪

    Non-thermalized dark matter is a cosmologically valid alternative to the paradigm of weakly interacting massive particles. For dark matter belonging to a $Z_2$-odd sector that contains in addition a thermalized mediator particle, dark matter production proceeds in general via both the freeze-in and superWIMP mechanism. We highlight their interplay and emphasize the connection to long-lived particles at colliders. For the explicit example of a colored t-channel mediator model we map out the entire accessible parameter space, cornered by bounds from the LHC, big bang nucleosynthesis and Lyman-alpha forest observations, respectively. We discuss prospects for the HL- and HE-LHC.

    hep-phastro-ph.COPRD(2018)·56 citations
20. 20*

    Indirect Signs of the Peccei-Quinn Mechanism

    Jordy de Vries🇺🇸 · Patrick Draper🇺🇸 · Kaori Fuyuto🇺🇸 · Jonathan Kozaczuk🇺🇸 · Dave Sutherland🇺🇸

    In the Standard Model, the renormalization of the QCD vacuum angle $\theta$ is extremely tiny, and small $\theta$ is technically natural. In the general Standard Model effective field theory (SMEFT), however, $\Delta \theta$ is quadratically divergent, reflecting the fact that new sources of hadronic CP-violation typically produce $\mathcal{O}(1)$ threshold corrections to $\theta$. The observation of such CP-violating interactions would therefore be in tension with solutions to the strong CP problem in which $\theta =0$ is an ultraviolet boundary condition, pointing to the Peccei-Quinn mechanism as the explanation for why $\theta$ is small in the infrared. We study the quadratic divergences in $\theta$ arising from dimension-6 SMEFT operators and discuss the discovery prospects for these operators at electric dipole moment experiments, the LHC, and future proton-proton colliders.

    hep-phPRD(2019)·28 citations
21. 21*

    Dark matter in Hidden Valley models with stable and unstable light dark mesons

    Hugues Beauchesne🇧🇷 · Enrico Bertuzzo🇧🇷 · Giovanni Grilli di Cortona🇧🇷

    It is a distinct possibility that a Hidden Valley sector would have a spectrum of light particles consisting of both stable and unstable dark mesons. The simultaneous presence of these two types of particles can lead to novel mechanisms for generating the correct dark matter relic abundance, which in turn can reflect themselves into new exotic signatures at colliders. We study the viability of such sectors for various Hidden Valley models and map the valid parameter space to possible collider signatures. Mediators studied include various scalar bifundamentals and a heavy $Z^{\prime }$. It is shown that in general bounds from direct and indirect detection can easily be avoided. In most of the allowed parameter space, the relic density is determined by stable mesons annihilating to unstable ones which in turn decay quickly to Standard Model particles. Dark mesons that decay mainly to heavier Standard Model fermions allow for more valid parameter space, though dark mesons are still allowed to decay exclusively to some of the lighter fermions. Possible exotic collider signatures include displaced vertices, emerging jets and semivisible jets.

    hep-phJHEP(2019)·70 citations
22. 22*

    Lowest vector tetraquark states: $Y(4260/4220)$ or $Z_c(4100)$

    Zhi-Gang Wang🇨🇳

    In this article, we take the $Y(4260/4220)$ as the vector tetraquark state with $J^{PC}=1^{--}$, and construct the $C{\gamma }_5\otimes {\overleftrightarrow{\partial }}_{\mu }\otimes {\gamma }_{5}C$ type diquark-antidiquark current to study its mass and pole residue with the QCD sum rules in details by taking into account the vacuum condensates up to dimension 10 in a consistent way. The predicted mass $M_Y=4.24\pm 0.10\mathrm{GeV}$ is in excellent agreement with experimental data and supports assigning the $Y(4260/4220)$ to be the $C{\gamma }_5\otimes {\overleftrightarrow{\partial }}_{\mu }\otimes {\gamma }_{5}C$ type vector tetraquark state, and disfavors assigning the $Z_c(4100)$ to be the $C{\gamma }_5\otimes {\overleftrightarrow{\partial }}_{\mu }\otimes {\gamma }_{5}C$ type vector tetraquark state. It is the first time that the QCD sum rules have reproduced the mass of the $Y(4260/4220)$ as a vector tetraquark state.

    hep-phEPJC(2018)·41 citations
23. 23*

    The Proton Radius Puzzle- Why We All Should Care

    Gerald A. Miller🇺🇸

    The status of the proton radius puzzle (as of the date of the Confer- ence) is reviewed. The most likely potential theoretical and experimental explanations are discussed. Either the electronic hydrogen experiments were not sufficiently accurate to measure the proton radius, the two- photon exchange effect was not properly accounted for, or there is some kind of new physics. I expect that upcoming experiments will resolve this issue within the next year or so.Ta

    ↳ physics.atom-phhep-phnucl-exnucl-th2 citations
24. 24*

    Evolution of the moments of multiplicity distributions

    Radka Sochorova🇨🇿 · Boris Tomasik🇸🇰 · Marcus Bleicher🇩🇪

    Measured moments of the multiplicity distribution for a given sort of particles are used in the literature for the determination of the phase transition parameters of hot QCD matter in ultrarelativistic heavy-ion collisions. We argue that the subsequent cooling in the hadronic phase, however, may drive the multiplicity distribution out of equilibrium. We use a master equation for the description of the evolution of the multiplicity distribution to demonstrate how the different moments depart away from their equilibrium values. If such moments were measured and interpreted as if they were equilibrated, one would obtain different apparent temperatures from different moments.

    ↳ nucl-thhep-phnucl-exPRC(2018)·5 citations
25. 25*

    Informational entropic Regge trajectories of meson families in AdS/QCD

    A. E. Bernardini🇧🇷 · R. da Rocha🇧🇷

    Bulk mesons propagating in chiral and gluon condensates, in a gravity background, are scrutinized in holographic soft wall AdS/QCD models, involving deformed dilatonic backgrounds. The configurational entropy of the $a_1$ axial vector, the $\rho$ vector, and the $f_0$ scalar meson families is then computed. Two types of informational entropic Regge trajectories are then obtained, where the logarithm of the mesons configurational entropy is expressed in terms of both the experimental meson mass spectra and their excitation number as well. Therefore the mass spectra of the next generation of elements in each meson family, besides being predicted as eigenvalues of Schrödinger-like equations, are estimated with better accuracy and discussed.

    ↳ hep-thhep-phPRD(2018)·47 citations
26. 26*

    De Sitter Vacua in No-Scale Supergravity

    John Ellis🇬🇧 · Balakrishnan Nagaraj🇺🇸 · Dimitri V. Nanopoulos🇺🇸 · Keith A. Olive🇺🇸

    No-scale supergravity is the appropriate general framework for low-energy effective field theories derived from string theory. The simplest no-scale Kähler potential with a single chiral field corresponds to a compactification to flat Minkowski space with a single volume modulus, but generalizations to single-field no-scale models with de Sitter vacua are also known. In this paper we generalize these de Sitter constructions to two- and multi-field models of the types occurring in string compactifications with more than one relevant modulus. We discuss the conditions for stability of the de Sitter solutions and holomorphy of the superpotential, and give examples whose superpotential contains only integer powers of the chiral fields.

    ↳ hep-thgr-qchep-phJHEP(2018)·42 citations
27. 27*

    Effects of LESA in Three-Dimensional Supernova Simulations with Multi-Dimensional and Ray-by-Ray-plus Neutrino Transport

    Robert Glas (1,2)🇩🇪 · H.-Thomas Janka (1)🇩🇪 · Tobias Melson (1)🇩🇪 · Georg Stockinger (1,2)🇩🇪 · Oliver Just (3,1) ((1) MPI f. Astrophysics, Garching, (2) Physik Department, TUM, (3) ABBL, RIKEN)🇯🇵

    A set of eight self-consistent, time-dependent supernova (SN) simulations in three spatial dimensions (3D) for 9 solar-mass and 20 solar-mass progenitors is evaluated for the presence of dipolar asymmetries of the electron lepton-number emission as discovered by Tamborra et al. and termed lepton-number emission self-sustained asymmetry (LESA). The simulations were performed with the Aenus-Alcar neutrino/hydrodynamics code, which treats the energy- and velocity-dependent transport of neutrinos of all flavors by a two-moment scheme with algebraic M1 closure. For each of the progenitors, results with fully multi-dimensional (FMD) neutrino transport and with ray-by-ray-plus (RbR+) approximation are considered for two different grid resolutions. While the 9 solar-mass models develop explosions, the 20 solar-mass progenitor does not explode with the employed version of simplified neutrino opacities. In all 3D models we observe the growth of substantial dipole amplitudes of the lepton-number (electron neutrino minus antineutrino) flux with stable or slowly time-evolving direction and overall properties fully consistent with the LESA phenomenon. Models with RbR+ transport develop LESA dipoles somewhat faster and with temporarily higher amplitudes, but the FMD calculations exhibit cleaner hemispheric asymmetries with a far more dominant dipole. In contrast, the RbR+ results display much wider multipole spectra of the neutrino-emission anisotropies with significant power also in the quadrupole and higher-order modes. Our results disprove speculations that LESA is a numerical artifact of RbR+ transport. We also discuss LESA as consequence of a dipolar convection flow inside of the nascent neutron star and establish, tentatively, a connection to Chandrasekhar's linear theory of thermal instability in spherical shells.

    ↳ astro-ph.HEhep-ph59 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.