Realistic Mass Research Articles

ANALYSIS OF TERRESTRIAL PLANET FORMATION BY THE GRAND TACK MODEL: SYSTEM ARCHITECTURE AND TACK LOCATION

ABSTRACT The Grand Tack model of terrestrial planet formation has emerged in recent years as the premier scenario used to account for several observed features of the inner solar system. It relies on the early migration of the giant planets to gravitationally sculpt and mix the planetesimal disk down to ∼1 au, after which the terrestrial planets accrete from material remaining in a narrow circumsolar annulus. Here, we investigate how the model fares under a range of initial conditions and migration course-change (“tack”) locations. We run a large number of N-body simulations with tack locations of 1.5 and 2 au and test initial conditions using equal-mass planetary embryos and a semi-analytical approach to oligarchic growth. We make use of a recent model of the protosolar disk that takes into account viscous heating, includes the full effect of type 1 migration, and employs a realistic mass–radius relation for the growing terrestrial planets. Our results show that the canonical tack location of Jupiter at 1.5 au is inconsistent with the most massive planet residing at 1 au at greater than 95% confidence. This favors a tack farther out at 2 au for the disk model and parameters employed. Of the different initial conditions, we find that the oligarchic case is capable of statistically reproducing the orbital architecture and mass distribution of the terrestrial planets, while the equal-mass embryo case is not.

Dibaryons with two strange quarks and total spin zero in a constituent quark model

We investigate the symmetry property and construct the wave function of the dibaryon states containing two strange quarks with S=0 in both the flavor SU(3) symmetric and breaking cases. We discuss how the color $\otimes$ isospin $\otimes$ spin states of dibaryon in the symmetry broking case of flavor SU(3) can be extracted from the fully antisymmetric states in flavor SU(3). The stability of the dibaryon against the strong decay into two baryons are then discussed, by using the variational method within a constituent quark model with a confining and color-spin interactions. To compare our results with that from lattice QCD in flavor SU(3) limit, we search for the stable H-dibaryon in a wide range of $\pi$ meson mass. We find that with the given potential, there is no compact six quark dibaryon state in the SU(3) flavor symmetry broken case with realistic quark masses as well as in flavor SU(3) symmetric case in a wide range of quark masses.

Lepton mass and mixing in a neutrino mass model based onS4flavor symmetry

We study a neutrino mass model based on [Formula: see text] flavor symmetry which accommodates lepton mass, mixing with nonzero [Formula: see text] and CP violation phase. The spontaneous symmetry breaking in the model is imposed to obtain the realistic neutrino mass and mixing pattern at the tree-level with renormalizable interactions. Indeed, the neutrinos get small masses from one [Formula: see text] doublet and two [Formula: see text] singlets in which one being in [Formula: see text] and the two others in [Formula: see text] under [Formula: see text] with both the breakings [Formula: see text] and [Formula: see text] are taken place in charged lepton sector and [Formula: see text] in neutrino sector. The model also gives a remarkable prediction of Dirac CP violation [Formula: see text] or [Formula: see text] in both the normal and inverted spectrum which is still missing in the neutrino mixing matrix. The relation between lepton mixing angles is also represented.

Radiative breaking of the minimal supersymmetric left–right model

We study a variation to the SUSY Left-Right symmetric model based on the gauge group $SU(3)_c\times SU(2)_L\times SU(2)_R\times U(1)_{BL}$. Beyond the quark and lepton superfields we only introduce a second Higgs bidoublet to produce realistic fermion mass matrices. This model does not include any $SU(2)_R$ triplets. We calculate renormalization group evolutions of soft SUSY parameters at the one-loop level down to low energy. We find that an $SU(2)_R$ slepton doublet acquires a negative mass squared at low energies, so that the breaking of $SU(2)_R\times U(1)_{BL}\rightarrow U(1)_Y$ is realized by a non-zero vacuum expectation value of a right-handed sneutrino. Small neutrino masses are produced through neutrino mixings with gauginos. Mass limits on the $SU(2)_R\times U(1)_{BL}$ sector are obtained by direct search results at the LHC as well as lepton-gaugino mixing bounds from the LEP precision data.

Fitting fermion masses and mixings in F-theory GUTs

We analyse the structure of Yukawa couplings in local SU(5) F-theory models with $E_7$ enhancement. These models are the minimal setting in which the whole flavour structure for the MSSM charged fermions is encoded in a small region of the entire compactification space. In this setup the $E_7$ symmetry is broken down to SU(5) by means of a 7-brane T-brane background, and further to the MSSM gauge group by means of a hypercharge flux that also implements doublet-triplet splitting. At tree-level only one family of quarks and charged leptons is massive, while the other two obtain hierarchically smaller masses when stringy non-perturbative effects are taken into account. We find that there is a unique $E_7$ model with such hierarchical flavour structure. The relative simplicity of the model allows to perform the computation of Yukawa couplings for a region of its parameter space wider than previous attempts, obtaining realistic fermion masses and mixings for large parameter regions. Our results are also valid for local models with $E_8$ enhancement, pointing towards a universal structure to describe realistic fermion masses within this framework.

Leptogenesis in E 6 × U(1) A SUSY GUT model

We study the thermal leptogenesis in the $E_6\times U(1)_A$ SUSY GUT model in which realistic masses and mixings of quarks and leptons can be realized. We show that the sufficient baryon number can be produced by the leptogenesis in the model, in which the mass parameter of the lightest right-handed neutrino is predicted to be smaller than $10^8$ GeV. The essential point is that the mass of the lightest right-handed neutrino can be enhanced in the model because it has a lot of mass terms whose mass parameters are predicted to be the same order of magnitude which is smaller than $10^8$ GeV. We show that O(10) enhancement for the lightest right-handed neutrino mass is sufficient for the observed baryon asymmetry. Note that such mass enhancements do not change the predictions of neutrino masses and mixings at the low energy scale in the $E_6$ model which has six right-handed neutrinos. In the calculation, we include the effects of supersymmetry and flavor in final states of the right-handed neutrino decay. We show that the effect of supersymmetry is quite important even in the strong washout regime when the effect of flavor is included. This is because the washout effects on the asymmetries both of the muon and the electron become weaker than that of the tau asymmetry.

Solution of bivariate population balance equations with high-order moment-conserving method of classes

In this work the high-order moment-conserving method of classes (HMMC) (Alopaeus et al., 2006) is extended to solve the bivariate Population Balance Equation (PBE). The method is capable of guaranteeing the internal consistency of the discretized equations for a generic moment set, including mixed-order moments of the distribution. The construction of the product tables in the case of aggregation, breakage and convection in internal coordinate space are discussed. Eventually, several test cases are considered to assess the accuracy of the method. The application to a realistic mass transfer problems in a liquid–liquid system is preliminarily discussed. The comparison with analytical solutions of pure aggregation problems shows that the proposed method is accurate with only a limited number of categories.

Quantitative rates of release from weathered nanocomposites are determined across 5 orders of magnitude by the matrix, modulated by the embedded nanomaterial

Major uses of nanomaterials are as functional fillers embedded in a solid matrix, such as plastics, tires, and coatings. Degradation of the solid matrix during the use phase can lead to a release of the nanomaterial and of fragments which might further degrade and release nanomaterials or smaller fragments in secondary processes. Here we focus on release induced by weathering, and specifically on quantitative rates of the mass of fragments released in the size range between 2nm and 10μm. We combine data from several experimental campaigns and 27 materials, using identical aging and sampling intensities, and identical analysis technique. The protocol specifies ISO4892 conditions of UV aging, optionally with rain, then immersed sonication, then size-selective quantification. All of these are elements of the protocol that was developed and pre-validated in a pilot international interlab comparison by the NanoRelease initiative. We rescaled releases for UV dose and immersion volumes, and find that the resulting release rates in units of mg release per MJ photons are determined across 5 orders of magnitude by the matrix (PE, PU, PA, POM, epoxy, cement), with less than a factor 10 up- or down-modulation by the embedded metal-oxide, carbonaceous, or organic nanomaterials. Variations of the aging and sampling conditions or a restriction of quantification to the size range from 2nm to 150nm do not affect this conclusion. Our results enable more realistic mass flow modeling and suggest limits in which release rates of nanocomposite materials can be estimated from rates measured on the neat matrix.

Modified Friedberg-Lee symmetry for neutrino mixing

In this letter, we put forward a special neutrino mass matrix which is invariant under a modified Friedberg-Lee (FL) transformation $\nu^{}_e \to \nu^{}_e-2\theta$ and $\nu^{}_{\mu, \tau} \to \nu^{}_{\mu, \tau}+\theta$ with $\theta$ being a space-time independent element of the Grassmann algebra. Compared to the original FL symmetry (with the transformation $\nu^{}_{e, \mu, \tau} \to \nu^{}_{e, \mu, \tau}+\theta$) which results in the TM2 neutrino mixing, the modified FL symmetry will lead us to the TM1 mixing which has a better agreement with the experimental results. While the original FL symmetry has to be broken in order to produce a realistic neutrino mass spectrum, the modified FL symmetry is allowed to remain intact and give us a vanishing $m^{}_1$. A combination of the FL symmetry with the $\mu$-$\tau$ reflection symmetry is also discussed.

Similarity and analytical solutions of free convective flow of dilatant nanofluid in a Darcian porous medium with multiple convective boundary conditions

This paper deals with an analytical solution of free convective flow of dilatant nanofluid past a vertical cone/plate. A two-phase mixture model is used for nanofluid in which the Brownian motion and thermophoretic diffusivities are the important slip mechanisms between solid and liquid phases. The governing transport equations along with physically realistic thermal and mass convective boundary conditions are reduced to similarity equations using relevant similarity transformations before being solved by homotopy analysis method. The effects of the governing parameters (Brownian motion, thermophoresis, convection–conduction, convection–diffusion, Lewis number, buoyancy ratio, and power-law) on the dimensionless velocity, temperature and nanoparticle volume fraction, friction and heat transfer rates are plotted and discussed. It is found that friction factor decreases with the increase in Le and Nr for both vertical plate and cone. The local Nusselt number decreases with the increase in the thermophoresis and Brownian motion parameters for both the plate and cone. The local Sherwood number increases with the Brownian motion parameter and decreases for thermophoresis parameter. The results have been compared with the published ones and an excellent agreement has been noticed.

The nonlinear equation of state of sea water and the global water mass distribution

AbstractThe role of nonlinearities of the equation of state (EOS) of seawater for the distribution of water masses in the global ocean is examined through simulations with an ocean general circulation model with various manipulated versions of the EOS. A simulation with a strongly simplified EOS, which contains only two nonlinear terms, still produces a realistic water mass distribution, demonstrating that these two nonlinearities are indeed the essential ones. Further simulations show that each of these two nonlinear terms affects a specific aspect of the water mass distribution: the cabbeling term is crucial for the formation of Antarctic Intermediate Water and the thermobaric term for the layering of North Atlantic Deep Water and Antarctic Bottom Water.

Modified Dincer and Dost Method for Predicting the Mass Transfer Coefficients in Solids

Abstract The analytical model developed by Dincer and Dost [3] for the estimation of diffusivities and mass transfer coefficients has been reviewed, and the equations used for the evaluation of the mass transfer coefficients have been corrected. The corrected equations have been used for the calculation of mass transfer coefficients from literature data. It was observed that the corrected diffusivities showed significant differences from the previously calculated values. The use of the modified equations in future drying calculations will lead to more realistic mass transfer coefficient values.

Three-body non-leptonic B decays and QCD factorization

We extend the framework of QCD factorization to non-leptonic B decays into three light mesons, taking as an example the decay B+→π+π+π−. We discuss the factorization properties of this decay in different regions of phase space. We argue that, in the limit of very large b-quark mass, the central region of the Dalitz plot can be described in terms of the B→π form factor and the B and π light-cone distribution amplitudes. The edges of the Dalitz plot, on the other hand, require different non-perturbative input: the B→ππ form factor and the two-pion distribution amplitude. We present the set-up for both regions to leading order in both αs and ΛQCD/mb and discuss how well the two descriptions merge. We argue that for realistic B-meson masses there is no perturbative center in the Dalitz plot, but that a systematic description might be possible in the context of two-pion states. As an example, we estimate the B→ρπ branching fraction beyond the quasi-particle approximation. We also discuss the prospects for studies of three-body and quasi-two-body non-leptonic B decays from QCD.

Cardiac fibrillation risks with TASER conducted electrical weapons.

The TASER(®) conducted electrical weapon (CEW) delivers electrical pulses that can temporarily incapacitate subjects. We analyzed the cardiac fibrillation risk with TASER CEWs. Our risk model accounted for realistic body mass index distributions, used a new model of effects of partial or oblique dart penetration and used recent epidemiological CEW statics.

Transonic galactic outflows in a dark matter halo with a central black hole

AbstractWe study fundamental properties of transonic galactic outflows in the gravitational potential of a cold dark matter halo (DMH) with a central super-massive black hole (SMBH) assuming an isothermal, steady and spherically symmetric state. Transonic solutions of galactic outflows are classified according to their topological features. As result, we find two types of transonic solutions distinguished by a magnitude relationship between the gravity of DMH and that of SMBH. The loci of transonic points for two types are different; one transonic point is formed at a central region (< 0.01kpc) and another is at a very distant region (> 100kpc). Also, mass fluxes and outflow velocities are different for two solutions. Thus, these solutions may differently influence the evolution of galaxies and the release of metals into the intergalactic space.Furthermore, we apply our model to the Sombrero galaxy. In this galaxy, the wide-spread hot gas is detected as the trace of galactic outflows while the star-formation rate is low, and the observed gas density distribution is similar to the hydrostatic state (Li et al. 2011). To solve this discrepancy, we propose a solution that this galaxy has a slowly accelerating outflow; the transonic point forms in a very distant region (~ 120 kpc) and the wide subsonic region spreads across the stellar distribution. Thus, the gas density distribution in the observed region is similar to the hydrostatic state. Such slowly accelerating outflows are different from high-velocity outflows conventionally studied (Igarashi et al. 2014).However, this isothermal model requires an unrealistically large mass flux. Then, we apply the polytropic model to this galaxy incorporating mass flux supplied by stellar components. We find that it can reproduce the observed gas density and the temperature distributions with the realistic mass flux. Thus, our polytropic model successfully demonstrates the existence of the slowly accelerating outflow in the Sombrero galaxy (Igarashi et al. 2015).

Generalized μ–τ symmetry and discrete subgroups of [formula omitted

The generalized μ–τ interchange symmetry in the leptonic mixing matrix U corresponds to the relations: |Uμi|=|Uτi| with i=1,2,3. It predicts maximal atmospheric mixing and maximal Dirac CP violation given θ13≠0. We show that the generalized μ–τ symmetry can arise if the charged lepton and neutrino mass matrices are invariant under specific residual symmetries contained in the finite discrete subgroups of O(3). The groups A4, S4 and A5 are the only such groups which can entirely fix U at the leading order. The neutrinos can be (a) non-degenerate or (b) partially degenerate depending on the choice of their residual symmetries. One obtains either vanishing or very large θ13 in case of (a) while only A5 can provide θ13 close to its experimental value in the case (b). We provide an explicit model based on A5 and discuss a class of perturbations which can generate fully realistic neutrino masses and mixing maintaining the generalized μ–τ symmetry in U. Our approach provides generalization of some of the ideas proposed earlier in order to obtain the predictions, θ23=π/4 and δCP=±π/2.

Nucleon self-energies for supernova equations of state

Nucleon self-energies and interaction potentials in supernova (SN) matter, which are known to have an important effect on nucleosynthesis conditions in SN ejecta are investigated. Corresponding weak charged-current interaction rates with unbound nucleons that are consistent with existing SN equations of state (EOSs) are specified. The nucleon self-energies are made available online as electronic tables. The discussion is mostly restricted to relativistic mean-field models. In the first part of the article, the generic properties of this class of models at finite temperature and asymmetry are studied. It is found that the quadratic expansion of the EOS in terms of asymmetry works reasonably well at finite temperatures and deviations originate mostly from the kinetic part. The interaction part of the symmetry energy is found to be almost temperature independent. At low densities, the account of realistic nucleon masses requires the introduction of a linear term in the expansion. Finally, it is shown that the important neutron-to-proton potential difference is given approximately by the asymmetry of the system and the interaction part of the zero-temperature symmetry energy. The results of different interactions are then compared with constraints from nuclear experiments and thereby the possible range of the potential difference is limited. In the second part, for a certain class of SN EOS models, the formation of nuclei is considered. Only moderate modifications are found for the self-energies of unbound nucleons that enter the weak charged-current interaction rates. This is because in the present approach the binding energies of bound states do not contribute to the single-particle energies of unbound nucleons.

Generation of magnetic holes in fully kinetic simulations of collisionless turbulence.

The results of three-dimensional fully kinetic simulations of decaying turbulence with the amplitude of the fluctuating magnetic field comparable to that of the mean field are presented. Coherent structures in the form of localized depressions in the magnitude of the magnetic field are observed to form self-consistently in the simulations. These depressions bear considerable resemblance to the so-called magnetic holes frequently reported in spacecraft observations. The structures are pressure-balanced and tend to be aligned with the local magnetic field. In the smallest structures observed, the decrease in the magnetic field strength is compensated by an increase in the electron perpendicular pressure, such that the transverse size of these structures is comparable to the electron gyroradius inside the depression. It is suggested that the structures evolve self-consistently out of the depressions in the fluctuating magnetic field, rather than being the consequence of instability growth and saturation. This is confirmed by additional, small-scale simulations, including those with realistic mass ratio between protons and electrons.

Fidelity of reduced and realistic electron mass ratio multi-scale gyrokinetic simulations of tokamak discharges

The first study using multi-scale (coupled ITG/TEM/ETG) gyrokinetic simulations at both reduced and realistic electron mass ratios, μ = (mD/me).5 = 20.0, 40.0 and 60.0, has been performed on a standard, Alcator C-Mod, L-mode discharge. Ion-scale (kθρs ∼ 1.0) and multi-scale (up to kθρe ∼ 0.8) gyrokinetic simulations are compared at different simulated mass ratios to investigate the fidelity of reduced electron mass ratio, multi-scale simulation through direct comparison with realistic mass ratio, multi-scale simulation. Detailed description of both the numerical setup and the turbulent scales required to obtain meaningful coupled ITG/TEM/ETG simulation is presented. Significant high-k driven (TEM/ETG) heat flux is found to exist at scales of approximately kθρe ∼ 0.1 at all mass ratios but can only be obtained by simulation capturing turbulence up to kθρe ∼ 1.0. At slightly reduced mass ratio, μ = 40.0, qualitative agreement with realistic mass simulation can be obtained in the studied discharge, consistent with intuition obtained from linear stability analysis. However, realistic electron mass is required for any robust quantitative comparison with experimental heat fluxes for the condition studied, as significant differences are observed at even slightly reduced electron mass ratio. The details of this numerical study are presented to provide a basis for future studies utilizing coupled ITG/TEM/ETG gyrokinetic simulation.

Forensic analysis of explosions: Inverse calculation of the charge mass

Forensic analysis of explosions consists of determining the point of origin, the explosive substance involved, and the charge mass. Within the EU FP7 project Hyperion, TNO developed the Inverse Explosion Analysis (TNO-IEA) tool to estimate the charge mass and point of origin based on observed damage around an explosion. In this paper, inverse models are presented based on two frequently occurring and reliable sources of information: window breakage and building damage. The models have been verified by applying them to the Enschede firework disaster and the Khobar tower attack. Furthermore, a statistical method has been developed to combine the various types of data, in order to determine an overall charge mass distribution.In relatively open environments, like for the Enschede firework disaster, the models generate realistic charge masses that are consistent with values found in forensic literature. The spread predicted by the IEA tool is however larger than presented in the literature for these specific cases. This is also realistic due to the large inherent uncertainties in a forensic analysis. The IEA-models give a reasonable first order estimate of the charge mass in a densely built urban environment, such as for the Khobar tower attack. Due to blast shielding effects which are not taken into account in the IEA tool, this is usually an under prediction. To obtain more accurate predictions, the application of Computational Fluid Dynamics (CFD) simulations is advised.The TNO IEA tool gives unique possibilities to inversely calculate the TNT equivalent charge mass based on a large variety of explosion effects and observations. The IEA tool enables forensic analysts, also those who are not experts on explosion effects, to perform an analysis with a largely reduced effort.