The rp-Process in Neutrino-driven Winds

Recent hydrodynamic simulations of core-collapse supernovae with accurate neutrino transport suggest that the bulk of the early neutrino-heated ejecta is proton rich, in which the production of some interesting proton-rich nuclei is expected. As suggested in recent nucleosynthesis studies, the rapid proton-capture (rp) process takes place in such proton-rich environments by bypassing the waiting point nuclei with the beta-lives of a few minutes via the faster capture of neutrons continuously supplied from the neutrino absorption by protons. In this study, the nucleosynthesis calculations are performed with the wide ranges of the neutrino luminosities and the electron fractions (Ye), using the semi-analytic models of proto-neutron star winds. The masses of proto-neutron stars are taken to be 1.4 Msolar and 2.0 Msolar, where the latter is regarded as the test for somewhat high entropy winds (about a factor of two). For Ye > 0.52, the neutrino-induced rp-process takes place in many wind trajectories, and the p-nuclei up to A ~ 130 are synthesized with interesting amounts. However, 92Mo is somewhat underproduced compared to those with similar mass numbers. For 0.46 < Ye < 0.49, on the other hand, 92Mo is significantly enhanced by the nuclear flows in the vicinity of the abundant 90Zr that originates from the alpha-process at higher temperature. The nucleosynthetic yields are averaged over the ejected masses of winds, and further the Ye distribution predicted by the recent hydrodynamic simulation of a core-collapse supernova. Comparison of the mass-Ye-averaged yields to the solar compositions implies that the neutrino-driven winds can be potentially the origin of light p-nuclei up to A ~ 110, including 92,94Mo and 96,98Ru that cannot be explained by other astrophysical sites.Comment: 29 pages, 18 figures, accepted for publication in Ap

The retina visual cycle is driven by cis retinol oxidation in the outer segments of cones

Vertebrate rod and cone photoreceptors require continuous supply of chromophore for regenerating their visual pigments after photoactivation. Cones, which mediate our daytime vision, demand a particularly rapid supply of 11-cis retinal chromophore in order to maintain their function in bright light. An important contribution to this process is thought to be the chromophore precursor 11-cis retinol, which is supplied to cones from Müller cells in the retina and subsequently oxidized to 11-cis retinal as part of the retina visual cycle. However, the molecular identity of the cis retinol oxidase in cones remains unclear. Here, as a first step in characterizing this enzymatic reaction, we sought to determine the subcellular localization of this activity in salamander red cones. We found that the onset of dark adaptation of isolated salamander red cones was substantially faster when exposing directly their outer vs. their inner segment to 9-cis retinol, an analogue of 11-cis retinol. In contrast, this difference was not observed when treating the outer vs. inner segment with 9-cis retinal, a chromophore analogue which can directly support pigment regeneration. These results suggest, surprisingly, that the cis-retinol oxidation occurs in the outer segments of cone photoreceptors. Confirming this notion, pigment regeneration with exogenously added 9-cis retinol was directly observed in the truncated outer segments of cones, but not in rods. We conclude that the enzymatic machinery required for the oxidation of recycled cis retinol as part of the retina visual cycle is present in the outer segments of cones

Spectral cues are necessary to encode azimuthal auditory space in the mouse superior colliculus.

Sound localization plays a critical role in animal survival. Three cues can be used to compute sound direction: interaural timing differences (ITDs), interaural level differences (ILDs) and the direction-dependent spectral filtering by the head and pinnae (spectral cues). Little is known about how spectral cues contribute to the neural encoding of auditory space. Here we report on auditory space encoding in the mouse superior colliculus (SC). We show that the mouse SC contains neurons with spatially-restricted receptive fields (RFs) that form an azimuthal topographic map. We found that frontal RFs require spectral cues and lateral RFs require ILDs. The neurons with frontal RFs have frequency tunings that match the spectral structure of the specific head and pinna filter for sound coming from the front. These results demonstrate that patterned spectral cues in combination with ILDs give rise to the topographic map of azimuthal auditory space

Holographic QCD Integrated back to Hidden Local Symmetry

We develop a previously proposed gauge-invariant method to integrate out infinite tower of Kaluza-Klein (KK) modes of vector and axialvector mesons in a class of models of holographic QCD (HQCD). The HQCD is reduced by our method to the chiral perturbation theory with the hidden local symmetry (HLS) having only the lowest KK mode identified as the HLS gauge boson. We take the Sakai-Sugimoto model as a concrete HQCD, and completely determine the ${\cal O} (p^4)$ terms as well as the ${\cal O}(p^2)$ terms from the DBI part and the anomaly-related (intrinsic parity odd) gauge-invariant terms from the CS part. Effects of higher KK modes are fully included in these terms. To demonstrate power of our method, we compute momentum-dependences of several form factors such as the pion electromagnetic form factors, the $\pi^0$-$\gamma$ and $\omega$-$\pi^0$ transition form factors compared with experiment, which was not achieved before due to complication to handle infinite sums. We also study other anomaly-related quantities like $\gamma^*$-$\pi^0$-$\pi^+$-$\pi^-$ and $\omega$-$\pi^0$-$\pi^+$-$\pi^-$ vertex functions.Comment: 4 eps figures, 37 pages, latex, typos fixed; some discussions and references added; fig.4 replace

Coherent versus non-coherent decode-and-forward relaying aided cooperative space-time shift keying

Motivated by the recent concept of Space-Time Shift Keying (STSK), we propose a novel cooperative STSK family, which is capable of achieving a flexible rate-diversity tradeoff, in the context of cooperative space-time transmissions. More specifically, we first propose a Coherent cooperative STSK (CSTSK) scheme, where each Relay Node (RN) activates Decode-and-Forward (DF) transmissions, depending on the success or failure of Cyclic Redundancy Checking (CRC). We invoke a bitto- STSK mapping rule, where according to the input bits, one of the Q pre-assigned dispersion vectors is activated to implicitly convey log2(Q) bits, which are transmitted in combination with the classic log2(L)-bit modulated symbol. Additionally, we introduce a beneficial dispersion vector design, which enables us to dispense with symbol-level Inter-Relay Synchronization (IRS). Furthermore, the Destination Node (DN) is capable of jointly detecting the signals received from the source-destination and relay-destination links, using a low-complexity single-stream-based Maximum Likelihood (ML) detector, which is an explicit benefit of our Inter-Element Interference (IEI)-free system model. More importantly, as a benefit of its design flexibility, our cooperative CSTSK arrangement enables us to adapt the number of the RNs, the transmission rate as well as the achievable diversity order. Moreover, we also propose a Differentially-encoded cooperative STSK (DSTSK) arrangement, which dispenses with CSI estimation at any of the nodes, while retaining the fundamental benefits of the cooperative CSTSK scheme

Dimension-six top-Higgs interaction and its effect in collider phenomenology

Measurement of the Yukawa interaction between the top quark and the Higgs boson should be useful to clarify the mechanism of fermion mass generation. We discuss the impact of non-standard interactions characterized by dimension-six operators on the effective top Yukawa coupling. The cross section of the process $e^-e^+ \to W^-W^+ \nu \bar \nu \to t \bar t \nu \bar \nu$ is calculated including these operators, and possible deviation from the standard model prediction is evaluated under the constraint from perturbative unitarity and current experimental data. We find that if the new physics scale is in a TeV region, the cross section can be significantly enhanced due to the non-standard interactions. Such a large effect should be detectable at the International Linear Collider.Comment: 22 pages, RevTex4, 20 eps figure

A light Higgs scenario based on the TeV-scale supersymmetric strong dynamics

We consider a model based on the supersymmetric QCD theory with N_c=2 and N_f=3. The theory is strongly coupled at the infrared scale \Lambda_H. Its low energy effective theory below \Lambda_H is described by the supersymmetric standard model with the Higgs sector that contains four iso-spin doublets, two neutral iso-spin singlets and two charged iso-spin singlets. If \Lambda_H is at the multi-TeV to 10 TeV, coupling constants for the F-terms of these composite fields are relatively large at the electroweak scale. Nevertheless, the SM-like Higgs boson is predicted to be as light as 125 GeV because these F-terms contribute to the mass of the SM-like Higgs boson not at the tree level but at the one-loop level. A large non-decoupling effect due to these F-terms appears in the one-loop correction to the triple Higgs boson coupling, which amounts to a few tens percent. Such a non-decoupling property in the Higgs potential realizes the strong first order phase transition, which is required for a successful scenario of electroweak baryogenesis

Off-diagonal Gluon Mass Generation and Infrared Abelian Dominance in Maximally Abelian Gauge in SU(3) Lattice QCD

In SU(3) lattice QCD formalism, we propose a method to extract gauge fields from link-variables analytically. With this method, we perform the first study on effective mass generation of off-diagonal gluons and infrared Abelian dominance in the maximally Abelian (MA) gauge in the SU(3) case. Using SU(3) lattice QCD, we investigate the propagator and the effective mass of the gluon fields in the MA gauge with U(1)_3 \timesU(1)_8 Landau gauge fixing. The Monte Carlo simulation is performed on $16^4$ at $\beta$=5.7, 5.8 and 6.0 at the quenched level. The off-diagonal gluons behave as massive vector bosons with the approximate effective mass $M_{\mathrm{off}} \simeq 1.1-1.2\mathrm{GeV}$ in the region of $r =0.3-0.8$fm, and the propagation is limited within a short range, while the propagation of diagonal gluons remains even in a large range. In this way, infrared Abelian dominance is shown in terms of short-range propagation of off-diagonal gluons. Furthermore, we investigate the functional form of the off-diagonal gluon propagator. The functional form is well described by the four-dimensional Euclidean Yukawa-type function $e^{-m_{\rm off}r}/r$ with $m_{\rm off} \simeq 1.3-1.4\mathrm{GeV}$ for $r = 0.1- 0.8$ fm. This also indicates that the spectral function of off-diagonal gluons has the negative-value region

Does the three site Higgsless model survive the electroweak precision tests at loop?

We complete the list of one loop renormalization group equations and matching conditions relevant for the computation of the electroweak precision parameters $S$ and $T$ in the three site Higgsless model. We obtain one-loop formulas for $S$ and $T$ expressed in terms of physical observables such as the KK gauge boson mass $M_{W'}$, the KK fermion mass $M$, and the KK gauge boson ($W'$) couplings with light quarks and leptons $g_{W'ff}$. It is shown that these physical observables, $M_{W'}$, $M$ and $g_{W'ff}$ are severely constrained by the electroweak precision data. Unlike the tree level analysis on the ideally delocalized fermion, we find that perfect fermiophobity of $W'$ is ruled out by the precision data. We also study the cutoff dependence of our analysis. Although the model is non-renormalizable, the dependence on the cutoff parameter $\Lambda$ is shown to be non-significant.Comment: 13pages, 5figures, minor corrections made, references adde