We investigate the formation of the double pulsar PSR $J0737\mathrm{\text{−}}3039$ and examine its most likely progenitors, taking into account the most recent and all currently available observational constraints. We show that the most likely kick velocity and progenitor parameters depend strongly on the consideration of the full five-dimensional probability distribution function for the magnitude and direction of the kick velocity imparted to pulsar B at birth, the mass of pulsar B’s presupernova helium star progenitor, and the presupernova orbital separation rather than marginalized one- or two-dimensional distributions for the kick velocity and progenitor mass. The priors that enter the analysis are the age of the system, the minimum helium star mass required to form a neutron star, the transverse systemic velocity, and the treatment of the unknown radial velocity. Since the latter cannot be measured observationally, we adopt a statistical approach and use theoretical radial-velocity distributions obtained from population synthesis calculations for coalescing double neutron stars. We find that when the minimum presupernova helium star mass required for neutron star formation is assumed to be $2.1M_{\odot }$, the most likely kick velocity ranges from $70\mathrm{km}{\mathrm{s}}^{-1}$ to $180\mathrm{km}{\mathrm{s}}^{-1}$. When, on the other hand, masses lower than $2.1M_{\odot }$ are allowed as neutron star progenitors, the most likely kick velocity can reach very low values (as low as a few $\mathrm{km}{\mathrm{s}}^{-1}$), although the majority of the models still yield most likely kick velocities of $50\mathrm{km}{\mathrm{s}}^{-1}$ to $170\mathrm{km}{\mathrm{s}}^{-1}$. Hence, we agree with Piran and Shaviv [T. Piran and N. J. Shaviv, Phys. Rev. Lett. 94, 051102 (2005).] that the observed system properties, including the low transverse systemic velocity, can indeed be compatible with low progenitor masses and low kick velocities. Equally important though, we show that this is not the only likely formation path of pulsar B, due to the role of different prior assumptions that are necessary in the analysis. Moreover, in contrast to earlier claims in the literature, we show that the proximity of the double pulsar to the Galactic plane and the small proper motion do not pose stringent constraints on the kick velocity and progenitor mass of pulsar B at all. Instead, the constraints imposed by the current orbital semimajor axis and eccentricity and the orbital dynamics of asymmetric supernova explosions turn out to be much more restrictive. We conclude that without further knowledge of the priors, the currently available observational constraints cannot be used to unambiguously favor a specific core-collapse and neutron star-formation mechanism. Both electron capture and neutrino-driven supernovae therefore remain viable formation mechanisms for pulsar B.

We derive new model independent constraints on the supersymmetric extensions of the standard model from the new experimental measurements of $B_s-{\overline{B}}_s$ mass difference. We point out that supersymmetry can still give a significant contribution to the $CP$ asymmetry of $B_s\to J/\psi \varphi$ that can be measured at the LHCb experiment. These new constraints on the $LL$ and $RR$ squark mixing severely restricted their possible contributions to the $CP$ asymmetries of $B\to \varphi K$ and $B\to {\eta }^{\prime }K$. Therefore, SUSY models with dominant $LR$ flavor mixing is the only way to accommodate the apparent deviation of $CP$ asymmetries from those expected in the standard model. Finally we present an example of SUSY nonminimal flavor model that can accommodate the new $\Delta M_{B_s}$ results and also induces significant $CP$ asymmetries in $B_s\to J/\psi \varphi$, $B\to \varphi K$, and $B\to {\eta }^{\prime }K$ processes.

Supersymmetric (SUSY) theories include many new parameters, some of which are $CP$-violating. Assuming that SUSY is found at a future high-energy collider, we examine the decay ${\tilde{t}}_2\to {\tilde{t}}_1{\tau }^{-}{\tau }^{+}$ with an eye to obtaining information about the new $CP$ phases. We show that there are two $CP$-violating asymmetries which can be large in some regions of the SUSY parameter space. These involve measuring one or both of the $\tau$ spins. These asymmetries are particularly sensitive to ${\varphi }_{A_t}$, the phase of the trilinear coupling $A_t$.

In a recent paper, Armoni, Shifman, and Veneziano (ASV) gave a formal nonperturbative proof of planar equivalence between the bosonic sectors of $\mathrm{SU}(N)$ super Yang-Mills theory and of a gauge theory with a massless quark in the antisymmetric two-indexes representation. In the case of three colors, the latter theory is nothing but one-flavor QCD. I will give a lattice version of the ASV proof of orientifold planar equivalence. It will be clear that it holds only in the strong-coupling and large-mass phase. Therefore, numerical simulations are necessary to test the validity of the orientifold planar equivalence in a physical region of the bare parameters on the lattice and to estimate the size of $1/N$ corrections.

The next-to-leading-order (NLO) term in the operator product expansion (OPE) of the quark propagator vector part $Z_{\psi }$ and the vertex function $g_1$ of the vector current in the Landau gauge should be dominated by the same $⟨A^2⟩$ condensate as in the gluon propagator. On the other hand, the perturbative part has been calculated to a very high precision thanks to Chetyrkin and collaborators. We test this on the lattice, with both clover and overlap fermion actions at $\beta =6.0$, 6.4, 6.6, 6.8. Elucidation of discretization artifacts appears to be absolutely crucial. First hypercubic artifacts are eliminated by a powerful method, which gives results notably different from the standard democratic method. Then, the presence of unexpected, very large, nonperturbative, $O(4)$ symmetric discretization artifacts, increasing towards small momenta, is demonstrated by considering $Z_V^{\mathrm{MOM}}$, which should be constant in the absence of such artifacts. They impede in general the analysis of OPE. However, in two special cases with overlap action—(1) for $Z_{\psi }$; (2) for $g_1$, but only at large $p^2$—we are able to identify the $⟨A^2⟩$ condensate; it agrees with the one resulting from gluonic Green functions. We conclude that the OPE analysis of quark and gluon Green function has reached a quite consistent status, and that the power corrections have been correctly identified. A practical consequence of the whole analysis is that the renormalization constant $Z_{\psi }$ ($=Z_2^{-1}$ of the momentum-subtraction (MOM) scheme) may differ sizably from the one given by democratic selection methods. More generally, the values of the renormalization constants may be seriously affected by the differences in the treatment of the various types of artifacts, and by the subtraction of power corrections.

We present branching fraction measurements of 12 $B$ meson decays of the form $B\to D^{(*)}{D}_{s(J)}^{(*)}$. The results are based on ${\rm Y}(4S)$ decays in $B\overline{B}$ pairs. One of the $B$ mesons is fully reconstructed and the other decays to two charm mesons, of which one is reconstructed, and the mass and momentum of the other is inferred by kinematics. Combining these results with previous exclusive branching fraction measurements, we determine $\mathcal{B}(D_s^{-}\to \varphi {\pi }^{-})=(4.62\pm {0.36}_{\mathrm{stat}.}\pm {0.51}_{\mathrm{syst}.})\%$, $\mathcal{B}(D_{sJ}(2460{)}^{-}\to D_s^{*-}{\pi }^0)=(56\pm {13}_{\mathrm{stat}.}\pm 9_{\mathrm{syst}.})\%$ and $\mathcal{B}(D_{sJ}(2460{)}^{-}\to D_s^{-}\gamma )=(16\pm 4_{\mathrm{stat}.}\pm 3_{\mathrm{syst}.})\%$.

In this paper the KTeV collaboration reports the analysis of $112.1\times {10}^3$ candidate $K_L\to {\pi }^{+}{\pi }^{-}\gamma$ decays including a background of $671\pm 41$ events with the objective of determining the photon production mechanisms intrinsic to the decay process. These decays have been analyzed to extract the relative contributions of the $CP$ violating bremsstrahlung process and the $CP$ conserving M1 and $CP$ violating E1 direct photon emission processes. The M1 direct photon emission amplitude and its associated vector form factor parameterized as $|{\tilde{g}}_{M1}|(1+\frac{a_1/a_2}{(M_{\rho }^2-M_K^2)+2M_K{E}_{\gamma }})$ have been measured to be $|{\tilde{g}}_{M1}|=1.198\pm 0.035(\mathrm{stat})\pm 0.086(\mathrm{syst})$ and $a_1/a_2=-0.738\pm 0.007(\mathrm{stat})\pm 0.018(\mathrm{syst}){\mathrm{GeV}}^2/c^2$ respectively. An upper limit for the $CP$ violating E1 direct emission amplitude $|g_{E1}|\le 0.21$ (90%CL) has been found. The overall ratio of direct photon emission (DE) to total photon emission including the bremsstrahlung process (IB) has been determined to be $\mathrm{DE}/(\mathrm{DE}+\mathrm{IB})=0.689\pm 0.021$ for $E_{\gamma }\ge 20\mathrm{MeV}$.

We present measurements of the $B\to \eta K\gamma$ branching fractions and upper limits for the $B\to {\eta }^{\prime }K\gamma$ branching fractions. For $B^{+}\to \eta K^{+}\gamma$ we also measure the time-integrated charge asymmetry. The data sample, collected with the BABAR detector at the Stanford Linear Accelerator Center, represents $232\times {10}^6$ produced $B\overline{B}$ pairs. The results for branching fractions and upper limits at 90% confidence level in units of ${10}^{-6}$ are: $\mathcal{B}(B^0\to \eta K^0\gamma )={11.3}_{-2.6}^{+2.8}\pm 0.6$, $\mathcal{B}(B^{+}\to \eta K^{+}\gamma )=10.0\pm 1.3\pm 0.5$, $\mathcal{B}(B^0\to {\eta }^{\prime }{K}^0\gamma )<6.6$, $\mathcal{B}(B^{+}\to {\eta }^{\prime }{K}^{+}\gamma )<4.2$. The charge asymmetry in the decay $B^{+}\to \eta K^{+}\gamma$ is ${\mathcal{A}}_{\mathrm{ch}}=-0.09\pm 0.12\pm 0.01$. The first errors are statistical and the second systematic.

We present a study of the decays ${\overline{B}}^0\to D^{(*)0}{\overline{K}}^{(*)0}$ using a sample of $226\times {10}^6$ ${\rm Y}(4S)\to B\overline{B}$ decays collected with the BABAR detector at the PEP-II asymmetric-energy $e^{+}{e}^{-}$ collider at SLAC. We report evidence for the decay of $B^0$ and ${\overline{B}}^0$ mesons to the $D^{*0}{K}_S^0$ final state with an average branching fraction $\mathcal{B}({\tilde{B}}^0\to D^{*0}{\tilde{K}}^0)\equiv (\mathcal{B}({\overline{B}}^0\to D^{*0}{\overline{K}}^0)+\mathcal{B}(B^0\to D^{*0}{K}^0))/2=(3.6\pm 1.2\pm 0.3)\times {10}^{-5}$. Similarly, we measure $\mathcal{B}({\tilde{B}}^0\to D^0{\tilde{K}}^0)\equiv (\mathcal{B}({\overline{B}}^0\to D^0{\overline{K}}^0)+\mathcal{B}(B^0\to D^0{K}^0))/2=(5.3\pm 0.7\pm 0.3)\times {10}^{-5}$ for the $D^0{K}_S^0$ final state. We measure $\mathcal{B}({\overline{B}}^0\to D^0{\overline{K}}^{*0})=(4.0\pm 0.7\pm 0.3)\times {10}^{-5}$ and set a 90% confidence level upper limit $\mathcal{B}({\overline{B}}^0\to {\overline{D}}^0{\overline{K}}^{*0})<1.1\times {10}^{-5}$. We determine the upper limit for the decay amplitude ratio $|\mathcal{A}({\overline{B}}^0\to {\overline{D}}^0{\overline{K}}^{*0})/\mathcal{A}({\overline{B}}^0\to D^0{\overline{K}}^{*0})|$ to be less than 0.4 at the 90% confidence level.

We report two-dimensional numerical results of jet formation driven by a magnetic field due to a current loop near a rapidly rotating black hole. We initially set the current loop along the intersection of the equatorial plane and the surface of the ergosphere around the black hole. In such magnetic configurations, there are magnetic flux tubes which bridge the region between the ergosphere and the corotating disk. The magnetic flux tube, which we call a “magnetic bridge,” is twisted rapidly by the plasma in the ergosphere due to the frame-dragging effect. The magnetic pressure of the magnetic flux tube increases and the strong magnetic pressure blows off the plasma near the ergosphere to form outflow. The outflow is pinched by the magnetic tension of the magnetic flux tube. Then, eventually, the jet is formed. That is, the magnetic bridges cannot be stationary, and they expand explosively to form a jet. The parameter survey of the background pressure shows that the radius of the collimated jet depends on the gas pressure of the corona. However, this does not mean the gas pressure collimates the jet. The gas pressure decelerates the jet and the pinch effect by the magnetic field becomes significant.

The purpose of this paper is to discuss in detail the use of scalar matter coupled to linearly polarized Einstein-Rosen waves as a probe to study quantum gravity in the restricted setting provided by this symmetry reduction of general relativity. We will obtain the relevant Hamiltonian and quantize it with the techniques already used for the purely gravitational case. Finally, we will discuss the use of particlelike modes of the quantized fields to operationally explore some of the features of quantum gravity within this framework. Specifically, we will study two-point functions, the Newton-Wigner propagator, and radial wave functions for one-particle states.

Assuming the Hubble parameter is a continuous and differentiable function of comoving time, we investigate necessary conditions for the quintessence to phantom phase transition in the quintom model. For power-law and exponential potential examples, we study the behavior of dynamical dark energy fields and the Hubble parameter near the transition time, and show that the phantom-divide line $\omega =-1$ is crossed in these models.

We report on further analysis of coherent microwave Cherenkov impulses emitted via the Askaryan mechanism from high-energy electromagnetic showers produced at the Stanford Linear Accelerator Center (SLAC). In this report, the time-domain based analysis of the measurements made with a broadband (nominally 1–18 GHz) log periodic dipole array antenna is described. The theory of a transmit-receive antenna system based on time-dependent effective height operator is summarized and applied to fully characterize the measurement antenna system and to reconstruct the electric field induced via the Askaryan process. The observed radiation intensity and phase as functions of frequency were found to agree with expectations from 0.75–11.5 GHz within experimental errors on the normalized electric field magnitude and the relative phase; ${\sigma }_{R|E|}=0.039\mu \mathrm{V}/\mathrm{MHz}/\mathrm{TeV}$ and ${\sigma }_{\varphi }=17°$. This is the first time this agreement has been observed over such a broad bandwidth, and the first measurement of the relative phase variation of an Askaryan pulse. The importance of validation of the Askaryan mechanism is significant since it is viewed as the most promising way to detect cosmogenic neutrino fluxes at $E_{\nu }\gtrsim {10}^{15}\mathrm{eV}$.

The current measurements of the cosmic ray energy spectrum at ultra-high energies ($\mathrm{E}>{10}^{19}\mathrm{eV}$) are characterized by large systematic errors and poor statistics. In addition, the experimental results of the two experiments with the largest published data sets, AGASA and HiRes, appear to be inconsistent with each other, with AGASA seeing an unabated continuation of the energy spectrum even at energies beyond the Greisen-Zatsepin-Kuzmin cutoff energy at ${10}^{19.6}\mathrm{eV}$. Given the importance of the related astrophysical questions regarding the unknown origin of these highly energetic particles, it is crucial that the extent to which these measurements disagree be well understood. Here we evaluate the consistency of the two measurements for the first time with a model-independent method that accounts for the large statistical and systematic errors of current measurements. We further compare the AGASA and HiRes spectra with the recently presented Auger spectrum. The method directly compares two measurements, bypassing the introduction of theoretical models for the shape of the energy spectrum. The inconsistency between the observations is expressed in terms of a Bayes factor, a standard statistic defined as the ratio of a separate parent source hypothesis to a single parent source hypothesis. Application to the data shows that the two-parent hypothesis is disfavored. We expand the method to allow comparisons between an experimental flux and that predicted by any model.

We present a model based on the implication of an exceptional $E_6$-GUT symmetry for the anomalous magnetic moment of the muon. We follow a particular chain of breakings with Higgses in the $\mathbf{78}$ and $\mathbf{351}$ representations. We analyze the radiative correction contributions to the muon mass and the effects of the breaking of the so-called Weinberg symmetry. We also estimate the range of values of the parameters of our model.

The idea of quark-lepton universality at high energies has recently been explored in unified theories based upon the quartification gauge group $SU(3{)}^4$. These schemes encompass a quark-lepton exchange symmetry that results upon the introduction of leptonic color. It has been demonstrated that, in models in which the quartification gauge symmetry is broken down to the standard model gauge group, gauge coupling constant unification can be achieved, and there is no unique scenario. The same is also true when the leptonic color gauge group is only partially broken, leaving a remnant $SU(2{)}_{\ell }$ symmetry at the standard model level. Here we perform an analysis of the neutrino mass spectrum of such models. We show that these models do not naturally generate small Majorana neutrino masses, thus correcting an error in our earlier quartification paper, but with the addition of one singlet neutral fermion per family there is a realization of seesaw suppressed masses for the neutrinos. We also show that these schemes are consistent with proton decay.

Precision tests of the standard model are essential for constraining models of new physics. Neutrino-electron elastic scattering offers a clean probe into many electroweak effects that are complimentary to the more canonical measurements done at collider facilities. Such reactions are rare, even as compared with the already tiny cross sections for neutrino-nucleon scattering, and competitive precision measurements have historically been challenging to obtain. Because of new existing and proposed high-flux neutrino sources, this is about to change. We present a topical survey of precision measurements that can be done with neutrino-electron scattering in light of these new developments. Specifically, we consider four distinct neutrino sources: nuclear reactors, neutrino factories, beta beams, and conventional beams. For each source we estimate the expected future precision of several representative observables, including the weak mixing angle, neutrino magnetic moments, and potential leptonic $Z^{\prime }$ couplings. We find that future neutrino-electron scattering experiments should add nontrivially to our understanding of fundamental physics.

We analyze the three-body charmless decay $B^{\pm }\to K^{\pm }{K}^{\pm }{K}^{\mp }$ using a sample of $226.0\pm 2.5$ million $B\overline{B}$ pairs collected by the BABAR detector. We measure the total branching fraction and $CP$ asymmetry to be $\mathcal{B}=(35.2\pm 0.9\pm 1.6)\times {10}^{-6}$ and $A_{CP}=(-1.7\pm 2.6\pm 1.5)\%$. We fit the Dalitz plot distribution using an isobar model and measure the magnitudes and phases of the decay coefficients. We find no evidence of $CP$ violation for the individual components of the isobar model. The decay dynamics is dominated by the $K^{+}{K}^{-}$ $S$-wave, for which we perform a partial-wave analysis in the region $m(K^{+}{K}^{-})<2\mathrm{GeV}/c^2$. Significant production of the $f_0(980)$ resonance, and of a spin zero state near $1.55\mathrm{GeV}/c^2$ are required in the isobar model description of the data. The partial-wave analysis supports this observation.

We propose some new simplifying ingredients for Feynman diagrams that seem necessary for random lattice formulations of superstrings. In particular, half the fermionic variables appear only in particle loops (similarly to loop momenta), reducing the supersymmetry of the constituents of the type IIB superstring to $N=1$, as expected from their interpretation in the $1/N$ expansion as super Yang-Mills.