118164401
Neutrino cyclotron radiation from superfluid vortexes in neutron stars: a new mechanism for pulsar spin down.
16233799
Bulge formation in very late-type galaxies
The dynamical evolution of super star clusters (SSCs) moving in the background of a dark matter halo has been investigated as a possible event responsible for the formation of bulges in late-type spirals. The underlying physical processes include sinking of SSCs due to the dynamical friction and stripping of SSCs on their way to the center. Based on the assumption of a universal density profile for the dark matter halo, and an isothermal model for the SSCs, our simulations have yielded bulges that are similar in many aspects to the observational ones. In particular, the derived surface density profiles can be well fitted by an exponential structure with nuclear cusps, which is consistent with HST observations.The preliminary simulations with the Burkert density profile yield very instructive predictions on the bulge formation, which is surely worth further investigating.
119331816
An Equilibrium Dark Matter Halo with the Burkert Profile
In this paper a prescription for generating an equilibrium spherical system depicted with cuspy density profiles is extended to a core density profile, the Burkert profile, which is observationally more suitable to dwarfs. By using a time-saving Monte Carlo method instead of N-body simulations, we show that the Burkert halo, which is initialized with a distribution function that depends only on energy, is in a practically stable equilibrium. The one generated with the local Maxwellian approximation is unstable, where the flat core density structure tends to steepen. This is fundamentally different from a previous study on a halo with a cuspy density profile. The deviation of the unstable “Burkert” from the initial Burkert profile is found to be closely related to taking a Gaussian as the velocity distribution at any given point. The significance of not using the local Maxwellian approximation is further demonstrated by exploring the dynamical evolution of compact super star clusters (SSCs) in the Burkert halo. In particular, the local Maxwellian approximation results in underestimating the dynamical friction and overestimating sinking time scale. Accordingly, this leads to a lower probability of forming massive bulges and young nuclear star clusters in bulgeless galaxies.
118335526
TeV SCALE MODELS OF NEUTRINO MASSES AND THEIR PHENOMENOLOGY
We review various TeV scale models for neutrino masses utilizing different types of seesaw mechanisms, higher dimensional operators, expanded gauge symmetries, or low scale extra dimensions. In addition, we discuss the implications of these models for the collider experiments and low energy lepton flavor violation searches.
122395245
Chiral symmetry breaking in QED for weak coupling
The authors examine the procedure for studying chiral symmetry breaking for weak coupling in QED. They note that while the lowest non-trivial order calculations using numerical solutions to the Schwinger-Dyson equation indicate a breaking of chiral symmetry, the neglected higher-order contributions to the effective potential have imaginary values which can indicate possible instabilities in the theory.
119301023
Lifting slepton masses with a non-universal, non-anomalous U(1)NAF′ in Anomaly Mediated SUSY Breaking
Abstract We extend the Minimum Supersymmetry Standard Model by a non-anomalous family (NAF) U ( 1 ) NAF ′ gauge symmetry. All gauge anomalies are cancelled with no additional exotics other than the three right-handed neutrinos. The FI D-terms associated with the U ( 1 ) NAF ′ symmetry lead to additional positive contributions to slepton squared masses. In a RG invariant way, this thus solves the tachyonic slepton mass problem in Anomaly Mediated Supersymmetry Breaking. In addition, the U ( 1 ) NAF ′ symmetry naturally gives rise to the fermion mass hierarchy and mixing angles, and determines the mass spectrum of the sparticles.
1384985
HerMES: SPECTRAL ENERGY DISTRIBUTIONS OF SUBMILLIMETER GALAXIES AT z > 4*
We present a study of the infrared properties for a sample of seven spectroscopically confirmed submillimeter galaxies (SMGs) at z > 4.0. By combining ground-based near-infrared, Spitzer IRAC and MIPS, Herschel SPIRE, and ground-based submillimeter/millimeter photometry, we construct their spectral energy distributions (SEDs) and a composite model to fit the SEDs. The model includes a stellar emission component at λ_(rest) 50 μm. Six objects in the sample are detected at 250 and 350 μm. The dust temperatures for the sources in this sample are in the range of 40-80 K, and their L_(FIR) ~ 10^(13) L_☉ qualifies them as hyper-luminous infrared galaxies. The mean FIR-radio index for this sample is around 〈q〉 = 2.2 indicating no radio excess in their radio emission. Most sources in the sample have 24 μm detections corresponding to a rest-frame 4.5 μm luminosity of Log_(10)(L_(4.5)/L_☉) = 11 ~ 11.5. Their L_(4.5)/L_(FIR) ratios are very similar to those of starburst-dominated SMGs at z ~ 2. The L_(CO) – L_(FIR) relation for this sample is consistent with that determined for local ULIRGs and SMGs at z ~ 2. We conclude that SMGs at z > 4 are hotter and more luminous in the FIR but otherwise very similar to those at z ~ 2. None of these sources show any sign of the strong QSO phase being triggered.
121710663
SPIN-2 GLUON - GRAVITON MODEL WITH BARYON NUMBER NONCONSERVATION
We have shown how a weak-strong gravity model with Higgs fields can contain a baryon-number-violating mechanism. If more than one set of Higgs particles are allowed, the Higgs-fermion coupling will generate the violation of baryon-number symmetry spontaneously. To illustrate our point, we present some numerical examples on quark and nucleon decay. We find that some of the quarks can decay into leptons, antileptons, and pions with very short lifetimes. The proton is found to be much more stable than the neutron and both have possible baryon-number-violating modes of decay with very long lifetimes.