A detailed general relativistic (GR) calculation of the neutrino path for a general metric describing a rotating star is studied. We have calculated the neutrino path along the equatorial and polar plane. The expression for the minimum photosphere radius (MPR) is obtained and matched with the Schwarzschild limit. The MPR is calculated for the stars with two different equations of state (EOS) each rotating with two different velocities, to analyze the dependence of EOS and rotational velocity on the MPR. The results show that the MPR for the hadronic star is much greater than the quark star and the MPR increases as the rotational velocity of the star decreases. The MPR along the polar plane is larger than that along the equatorial plane.

The electron and muon number violating muonium-antimuonium oscillation process in an extended minimal supersymmetric standard model is investigated. The minimal supersymmetric standard model is modified by the inclusion of three right-handed neutrino superfields. While the model allows the neutrino mass terms to mix among the different generations, the sneutrino and slepton mass terms have only intragenerational lepton number violation and not intergenerational lepton number mixing. Thus, the muonium-antimuonium conversion can then be used to constrain those model parameters, which avoid further constraints from the $\mu \to e\gamma$ decay bounds. For a wide range of parameter values, the contributions to the muonium-antimuonium oscillation time scale are at least 2 orders of magnitude below the sensitivity of current experiments. However, if the ratio of the two Higgs field vacuum expectation values, $\tan \beta$, is very small, there is a limited possibility that the contributions are large enough for the present experimental limit to provide an inequality relating $\tan \beta$ to the light neutrino mass scale $m_{\nu }$, which is generated by the seesaw mechanism. The resultant lower bound on $\tan \beta$ as a function of $m_{\nu }$ is more stringent than the analogous bounds arising from the muon and electron anomalous magnetic moments as computed using this model.

We present thick de Sitter brane solutions which are supported by two interacting phantom scalar fields in five-, six-, and seven-dimensional spacetime. It is shown that for all cases regular solutions with anti–de Sitter asymptotic (5D problem) and a flat asymptotic far from the brane (6D and 7D cases) exist. We also discuss the stability of our solutions.

The perturbations in the electron number density during recombination contributes to the cosmic microwave background bispectrum through second order terms. Perturbations in the electron density can be a factor of $\sim 5$ larger than the baryon density fluctuations on large scales as shown in the calculations by Novosyadlyj. This raises the possibility that the contribution to the bispectrum arising from perturbations in the optical depth may be non-negligible. We calculate this bispectrum and find it to peak for squeezed triangles and of peak amplitude of the order of primordial non-Gaussianity of a local type with $f_{NL}\approx 0.05\sim -1$ depending on the $\ell$ modes being considered. This is because the shape of the bispectrum is different from the primordial one although it peaks for squeezed configurations, similar to the local type primordial non-Gaussianity.

We model tribimaximal lepton mixing from first principles in a way that avoids the problem of the vacuum alignment characteristic of such models. This is achieved by using a softly broken $A_4$ symmetry realized with an isotriplet fermion, also triplet under $A_4$. No scalar $A_4$ triplet is introduced. This represents one possible realization of general schemes characterized by the minimal set of either three or five physical parameters. In the three parameter versions the neutrinoless double beta mass parameter $m_{ee}$ vanishes, while in the five parameter schemes the absolute scale of neutrino mass, although not predicted, is related to the two Majorana phases. The model realization we discuss is potentially testable at the LHC through the peculiar leptonic decay patterns of the fermionic and scalar triplets.

We present a framework for phenomenological lattice QCD calculations which makes use of a tree-level Symanzink improved action for gluons and stout-link Wilson fermions. We give details of our efficient HMC/RHMC algorithm and present a scaling study of the low-lying $N_f=3$ baryon spectrum. We find a scaling region that extends to $a\lesssim 0.16\mathrm{fm}$ and conclude that our action and algorithm are suitable for large scale phenomenological investigations of $N_f=2+1$ QCD. We expect this conclusion to hold for other comparable actions.

In this work, we have investigated whether $Y(4260)$ and $Z_2^{+}(4250)$ could be $D_{1}D$ or $D_0{D}^{*}$ molecules in the framework of meson exchange model. The off-diagonal interaction induced by $\pi$ exchange plays a dominant role. The $\sigma$ exchange has been taken into account, which leads to diagonal interaction. The contribution of $\sigma$ exchange is not favorable to the formation of the molecular state with $I^G(J^{PC})=0^{-}(1^{--})$; however, it is beneficial to the binding of the molecule with $I^G(J^P)=1^{-}(1^{-})$. Light vector meson exchange leads to diagonal interaction as well. For $Z_2^{+}(4250)$, the contribution from $\rho$ and $\omega$ exchange almost cancels each other. For the currently allowed values of the effective coupling constants and a reasonable cutoff $\Lambda$ in the range 1–2 GeV, we find that $Y(4260)$ could be accommodated as a $D_{1}D$ and $D_0{D}^{*}$ molecule, whereas the interpretation of $Z_2^{+}(4250)$ as a $D_{1}D$ or $D_0{D}^{*}$ molecule is disfavored. The bottom analog of $Y(4260)$ and $Z_2^{+}(4250)$ may exist, and the most promising channels to discover them are ${\pi }^{+}{\pi }^{-}{\rm Y}$ and ${\pi }^{+}{\chi }_{b1}$, respectively.

Data collected in run II of the Fermilab Tevatron are searched for indications of new electroweak-scale physics. Rather than focusing on particular new physics scenarios, CDF data are analyzed for discrepancies with the standard model prediction. A model-independent approach (Vista) considers gross features of the data, and is sensitive to new large cross-section physics. Further sensitivity to new physics is provided by two additional algorithms: a Bump Hunter searches invariant mass distributions for “bumps” that could indicate resonant production of new particles, and the Sleuth procedure scans for data excesses at large summed transverse momentum. This combined global search for new physics in $2.0{\mathrm{fb}}^{-1}$ of $p\overline{p}$ collisions at $\sqrt{s}=1.96\mathrm{TeV}$ reveals no indication of physics beyond the standard model.

In the AdS/CFT description of four-dimensional QCD matter undergoing Bjorken expansion, does the holographic energy-momentum tensor contain a Casimir-type contribution that should not be attributed to thermal matter? When the bulk isometry ansatz that yielded such a Casimir term for $(1+1)$-dimensional boundary matter is generalized to a four-dimensional boundary, we show that a Casimir term does not arise, owing to singularities in the five-dimensional bulk solution. The geometric reasons are traced to a difference between the isometries of ${\mathrm{AdS}}_3$ and ${\mathrm{AdS}}_{d+1}$ for $d\ge 3$.

We study the AdS/CFT thermodynamics of the spatially isotropic counterpart of the Bjorken similarity flow in $d$-dimensional Minkowski space with $d\ge 3$, and of its generalization to linearly expanding $d$-dimensional Friedmann-Robertson-Walker cosmologies with arbitrary values of the spatial curvature parameter $k$. The bulk solution is a nonstatic foliation of the generalized Schwarzschild-AdS black hole with a horizon of constant curvature $k$. The boundary matter is an expanding perfect fluid that satisfies the first law of thermodynamics for all values of the temperature and the spatial curvature, but it admits a description as a scale-invariant fluid in local thermal equilibrium only when the inverse Hawking temperature is negligible compared with the spatial curvature length scale. A Casimir-type term in the holographic energy-momentum tensor is identified from the threshold of black hole formation and is shown to take different forms for $k\ge 0$ and $k<0$.

Nonperturbative and lattice methods indicate that Gribov copies modify the infrared behavior of gauge theories and cause a suppression of gluon propagation. We investigate whether this can be implemented in a modified perturbation theory. The minimal modification proceeds via a nonlocal generalization of the Fadeev-Popov ghost that automatically decouples from physical states. The expected scale invariance of the physics associated with Gribov copies leads to the emergence of a nontrivial infrared fixed point. For a range of a scaling exponent the gauge bosons exhibit unparticlelike behavior in the infrared. The confining regime of interest for QCD requires a larger scaling exponent, but then the severity of ghost dominance upsets naive power counting for the infrared scaling behavior of amplitudes.

We consider the phase transition of a string with tension ${\epsilon }_1$ to a string with a smaller tension ${\epsilon }_2$ at finite temperature. For sufficiently small temperatures the transition proceeds through thermally catalyzed quantum tunneling, and we calculate in arbitrary number of dimensions the thermal catalysis factor. At ${\epsilon }_2=0$ the found formula for the decay rate also describes a breakup of a metastable string into two pieces.

The problem of nonuniqueness of minimal coupling procedure for Einstein-Cartan (EC) gravity with matter is investigated. It is shown that the predictions of the theory of gravity with fermionic matter can radically change if the freedom of the addition of a divergence to the flat space matter Lagrangian density is exploited. The well-known gravity-induced four-fermion interaction is shown to reveal unexpected features. The solution to the problem of nonuniqueness of minimal coupling of EC gravity is argued to be necessary in order for the theory to produce definite predictions. In particular, the EC theory with fermions is shown to be indistinguishable from usual the general relativity on the effective level, if the flat space fermionic Lagrangian is appropriately chosen. Hence, the solution to the problem of nonuniqueness of minimal coupling procedure is argued to be necessary if EC theory is to be experimentally verifiable. It could also enable experimental tests of theories based on EC, such as the loop approach to quantization of gravitational field. Some ideas of how the arbitrariness incorporated in EC theory could be restricted or even eliminated are presented.

We study the flavor sector in models where the three families of matter are unified in a (16, 3) representation of the $SO(10)\times A_4$ group. The necessary ingredients to realize tribimaximal mixing in the lepton sector are identified systematically. The nonrenormalizable operators contributing to the fermion mass matrices play an important role. We also present a mechanism to explain the interfamily mass hierarchy of quarks and charged leptons, which relies on a “universal seesaw” mechanism and is compatible with tribimaximal mixing.

The recent B factories measurements of new states exhibit, in most of the decays, charmonium-like resonances. Among them we study the $J^{PC}=1^{--}$ hidden charm resonances in order to assert if they are $q\overline{q}$ states or more complicated structures. The energy spectrum, electromagnetic, and strong decays are studied in a constituent quark model which has been able to reproduce the hadronic phenomenology and the baryon-baryon interaction. Most of the reported states are nicely interpreted as $q\overline{q}$ pairs. The new $\psi (4360)$ state is found as the $4S$ state and the $\psi (4415)$ as the $3D$ which differs from the standard assignment. Some of the states, such as the $Y(4260)$, cannot be accommodated as $q\overline{q}$ pairs.

The SciBooNE Collaboration has performed a search for charged current coherent pion production from muon neutrinos scattering on carbon, ${\nu }_{\mu }{}^{12}\mathrm{C}\to {\mu }^{-}{}^{12}\mathrm{C}{\pi }^{+}$, with two distinct data samples. No evidence for coherent pion production is observed. We set 90% confidence level upper limits on the cross section ratio of charged current coherent pion production to the total charged current cross section at $0.67\times {10}^{-2}$ at mean neutrino energy 1.1 GeV and $1.36\times {10}^{-2}$ at mean neutrino energy 2.2 GeV.

In this experiment we aim to detect Kaluza-Klein (KK) excitations of the bulk gauge field, emitted in a bremsstrahlung process on solar plasma constituents, by looking at a process analogous to the photoelectric effect inside the HPGe detector. Using a generic feature of the underlying effective theory that the unknown four-dimensional gauge coupling is independent of the number of extra large dimensions $\delta$, we show that the expected number of events in the detector is insensitive to the true scale of quantum gravity for $\delta =2$. With the entire data collection time of 202 days in the energy interval 1.7–3.8 keV, the number of events detected was as low as $1.1\times {10}^6$, compared to $2.7\times {10}^6$ from the expected high multiplicity of the solar KK excitations for $\delta =2$. Hence, our bound from the presumed existence of new forces associated with additional gauge bosons actually conforms with very stringent bounds set from various astrophysical considerations. Baring any modifications of the infrared part of the KK spectrum, this bound would therefore rule out the possibility of observing any signal at the LHC for $\delta =2$. Although a dependence on the fundamental scale referring to $(4+\delta )$-dimensional gravity turns on again for $\delta =3$, the experimental sensitivity of the present setup proves insufficient to draw any constraint for $\delta >2$.

We construct rolling tachyon solutions of open and boundary string field theory (OSFT and BSFT, respectively), in the bosonic and supersymmetric (susy) case. The wildly oscillating solution of susy OSFT is recovered, together with a family of time-dependent BSFT solutions, for the bosonic and susy string. These are parametrized by an arbitrary constant $r$ involved in solving the Green equation of the target fields. When $r=0$ we recover previous results in BSFT, whereas for $r$ attaining the value predicted by OSFT it is shown that the bosonic OSFT solution is the derivative of the boundary one; in the supersymmetric case the relation between the two solutions is more complicated. This technical correspondence sheds some light on the nature of wild oscillations, which appear in both theories whenever $r>0$.

Recently, two independent calculations have been presented of finite-mass (“self-force”) effects on the orbit of a point mass around a Schwarzschild black hole. While both computations are based on the standard mode-sum method, they differ in several technical aspects, which makes comparison between their results difficult—but also interesting. Barack and Sago [Phys. Rev. D 75, 064021 (2007)] invoke the notion of a self-accelerated motion in a background spacetime, and perform a direct calculation of the local self-force in the Lorenz gauge (using numerical evolution of the perturbation equations in the time domain); Detweiler [Phys. Rev. D 77, 124026 (2008)] describes the motion in terms a geodesic orbit of a (smooth) perturbed spacetime, and calculates the metric perturbation in the Regge-Wheeler gauge (using frequency-domain numerical analysis). Here we establish a formal correspondence between the two analyses, and demonstrate the consistency of their numerical results. Specifically, we compare the value of the conservative $O(\mu )$ shift in $u^t$ (where $\mu$ is the particle’s mass and $u^t$ is the Schwarzschild $t$ component of the particle’s four-velocity), suitably mapped between the two orbital descriptions and adjusted for gauge. We find that the two analyses yield the same value for this shift within mere fractional differences of $\sim {10}^{-5}–{10}^{-7}$ (depending on the orbital radius)—comparable with the estimated numerical error.

Quasiequilibrium models of rapidly rotating triaxially deformed stars are computed in general relativistic gravity, assuming a conformally flat spatial geometry (Isenberg-Wilson-Mathews formulation) and a polytropic equation of state. Highly deformed solutions are calculated on the initial slice covered by spherical coordinate grids, centered at the source, in all angular directions up to a large truncation radius. Constant rest mass sequences are calculated from nearly axisymmetric to maximally deformed triaxial configurations. Selected parameters are to model (proto-) neutron stars; the compactness is $M/R=0.001$, 0.1, 0.14, and 0.2 for polytropic index $n=0.3$ and $M/R=0.001$, 0.1, 0.12, and 0.14 for $n=0.5$, where $M/R$ refers to that of a nonrotating spherical star having the same rest mass. We confirmed that the triaxial solutions exist for these parameters as in the case of Newtonian polytropes. However, it is also found that the triaxial sequences become shorter for higher compactness, and those disappear at a certain large compactness for the $n=0.5$ case. In the scenario of the contraction of proto-neutron stars being subject to strong viscosity and rapid cooling, it is plausible that, once the viscosity driven secular instability sets in during the contraction, the proto-neutron stars are always maximally deformed triaxial configurations, as long as the compactness and the equation of state parameters allow such triaxial sequences. Detection of gravitational waves from such sources may be used as another probe for the nuclear equation of state.