There is growing interest in using 3-dimensional neutral hydrogen mapping with the redshifted 21 cm line as a cosmological probe. However, its utility depends on many assumptions. To aid experimental planning and design, we quantify how the precision with which cosmological parameters can be measured depends on a broad range of assumptions, focusing on the 21 cm signal from $6<z<20$. We cover assumptions related to modeling of the ionization power spectrum, to the experimental specifications like array layout and detector noise, to uncertainties in the reionization history, and to the level of contamination from astrophysical foregrounds. We derive simple analytic estimates for how various assumptions affect an experiment’s sensitivity, and we find that the modeling of reionization is the most important, followed by the array layout. We present an accurate yet robust method for measuring cosmological parameters that exploits the fact that the ionization power spectra are rather smooth functions that can be accurately fit by 7 phenomenological parameters. We find that for future experiments, marginalizing over these nuisance parameters may provide constraints almost as tight on the cosmology as if 21 cm tomography measured the matter power spectrum directly. A future square kilometer array optimized for 21 cm tomography could improve the sensitivity to spatial curvature and neutrino masses by up to 2 orders of magnitude, to $\Delta {\Omega }_k\approx 0.0002$ and $\Delta m_{\nu }\approx 0.007\mathrm{eV}$, and give a $4\sigma$ detection of the spectral index running predicted by the simplest inflation models.

We compute, in $\mathcal{N}=4$ super Yang-Mills theory, the four point correlation function of $R$-currents in the Regge limit in the leading logarithmic approximation at weak coupling. Such a correlator is the closest analog to photon-photon scattering within QCD, and there is a well-defined procedure to perform the analogous computation at strong coupling via the AdS/CFT correspondence. The main result of this paper is, on the gauge theory side, the proof of Regge factorization and the explicit computation of the $R$-current impact factors.

We demonstrate how to systematically test a well-motivated mechanism for neutrino mass generation (type II seesaw) at the LHC, in which a Higgs triplet is introduced. In the optimistic scenarios with a small Higgs triplet vacuum expectation value $v_{\Delta }<{10}^{-4}\mathrm{GeV}$, one can look for clean signals of lepton-number violation in the decays of doubly charged ($H^{\pm \pm }$) and singly charged ($H^{\pm }$) Higgs bosons to distinguish the normal hierarchy (NH), the inverted hierarchy (IH), and the quasidegenerate (QD) spectrum for the light neutrino masses. The observation of either $H^{+}\to {\tau }^{+}\overline{\nu }$ or $H^{+}\to e^{+}\overline{\nu }$ will be particularly robust for the spectrum test since they are independent of the unknown Majorana phases. The $H^{++}$ decays moderately depend on a Majorana phase ${\Phi }_2$ in the NH, but sensitively depend on ${\Phi }_1$ in the IH. In a less favorable scenario $v_{\Delta }>2\times {10}^{-4}\mathrm{GeV}$, when the leptonic channels are suppressed, one needs to observe the decays $H^{+}\to W^{+}{H}_1$ and $H^{+}\to t\overline{b}$ to confirm the triplet-doublet mixing which in turn implies the existence of the same gauge-invariant interaction between the lepton doublet and the Higgs triplet responsible for the neutrino mass generation. In the most optimistic situation, $v_{\Delta }\sim {10}^{-4}\mathrm{GeV}$, both channels of the lepton pairs and gauge boson pairs may be available simultaneously. The determination of their relative branching fractions would give a measurement for the value of $v_{\Delta }$.

We study the heavy-heavy-light quark ($QQq$) potential in SU(3) quenched lattice QCD, and discuss one of the roles of the finite-mass valence quark in the interquark potential. Monte Carlo simulations are performed with the standard gauge action on the ${16}^4$ lattice at $\beta =6.0$ and the $O(a)$-improved Wilson fermion action at four hopping parameters. For statistical improvement, the gauge configuration is fixed with the Coulomb gauge. We calculate the potential energy of $QQq$ systems as a function of the inter-heavy-quark distance $R$ in the range of $R\le 0.8\mathrm{fm}$. The $QQq$ potential is well described with a Coulomb plus linear potential, and the effective string tension between the two heavy quarks is significantly smaller than the string tension $\sigma \simeq 0.89\mathrm{GeV}/\mathrm{fm}$. It would generally hold that the effect of the finite-mass valence quark reduces the inter-two-quark confinement force in baryons.

A compact general integral formula is derived from which the fermionic contribution to the one-loop coefficient in the perturbative expansion of the $\overline{MS}$ coupling in powers of the bare lattice coupling can be extracted. It is seen to reproduce the known results for unimproved naive, staggered and Wilson fermions, and has advantageous features which facilitate the evaluation in the case of improved lattice fermion formulations. This is illustrated in the case of Wilson clover fermions, and an expression in terms of known lattice integrals is obtained in this case which gives the coefficient to much greater numerical accuracy than in the previous literature.

We calculate a two-pion wave function for the $I=2$ $S$-wave two-pion system with a finite scattering momentum and estimate the interaction range between two pions, which allows us to examine the validity of a necessary condition for the finite size formula presented by Rummukainen and Gottlieb. We work in the quenched approximation employing the plaquette gauge action for gluons and the improved Wilson action for quarks at $1/a=1.63\mathrm{GeV}$ on the ${32}^3\times 120$ lattice. The quark masses are chosen to give $m_{\pi }=0.420$, 0.488, and 0.587 GeV. We find that the energy dependence of the interaction range is small and the necessary condition is satisfied for our range of the quark mass and the scattering momentum, $k\le 0.16\mathrm{GeV}$. We also find that the scattering phase shift can be obtained with a smaller statistical error from the two-pion wave function than from the two-pion time correlator.

We present a quenched lattice calculation of the weak nucleon form factors: vector [$F_V(q^2)$], induced tensor [$F_T(q^2)$], axial vector [$F_A(q^2)$] and induced pseudoscalar [$F_P(q^2)$] form factors. Our simulations are performed on three different lattice sizes $L^3\times T={24}^3\times 32$, ${16}^3\times 32$, and ${12}^3\times 32$ with a lattice cutoff of $a^{-1}\approx 1.3\mathrm{GeV}$ and light quark masses down to about $1/4$ the strange quark mass ($m_{\pi }\approx 390\mathrm{MeV}$) using a combination of the DBW2 gauge action and domain wall fermions. The physical volume of our largest lattice is about $(3.6\mathrm{fm}{)}^3$, where the finite volume effects on form factors become negligible and the lower momentum transfers ($q^2\approx 0.1{\mathrm{GeV}}^2$) are accessible. The $q^2$ dependences of form factors in the low $q^2$ region are examined. It is found that the vector, induced tensor, and axial-vector form factors are well described by the dipole form, while the induced pseudoscalar form factor is consistent with pion-pole dominance. We obtain the ratio of axial to vector coupling $g_A/g_V=F_A(0)/F_V(0)=1.219(38)$ and the pseudoscalar coupling $g_P=m_{\mu }{F}_P(0.88m_{\mu }^2)=8.15(54)$, where the errors are statistical errors only. These values agree with experimental values from neutron $\beta$ decay and muon capture on the proton. However, the root mean-squared radii of the vector, induced tensor, and axial vector underestimate the known experimental values by about 20%. We also calculate the pseudoscalar nucleon matrix element in order to verify the axial Ward-Takahashi identity in terms of the nucleon matrix elements, which may be called as the generalized Goldberger-Treiman relation.

The hadronic $k_{\perp }$-spectrum inside a high-energy jet is determined including corrections of relative magnitude $\mathcal{O}(\sqrt{{\alpha }_s})$ with respect to the Modified Leading Logarithmic Approximation (MLLA) in the limiting spectrum approximation (assuming an infrared cutoff $Q_0={\Lambda }_{\mathrm{QCD}}$) and beyond ($Q_0\ne {\Lambda }_{\mathrm{QCD}}$). The results in the limiting spectrum approximation are found to be, after normalization, in impressive agreement with preliminary measurements by the CDF Collaboration, unlike what occurs at MLLA, pointing out small overall nonperturbative contributions. Within the same framework, 2-particle correlations inside a jet are also predicted at next-to-MLLA and compared to previous MLLA calculations.

Two-body charmed decays $B_{(s)}\to D_{(s)}P$, $D_{(s)}^{*}P$, $D_{(s)}V$, and $D_{(s)}^{*}V$, where $P$ and $V$ denote the light pseudoscalar meson and vector meson, respectively, are analyzed in the perturbative QCD (pQCD) approach. Using the experimental data of six $B\to DP$ channels, we test the $D$ meson wave function by ${\chi }^2$ fit. We give the branching ratios of all the charmed $B$ decay channels, most of which agree with experiments amazingly well. The predicted $B_s$ decays can be confronted with the future experimental data. By straightforward calculations, our pQCD approach gives the right relative strong phase of $a_2/a_1$ that agrees with experiments. We also predict the percentage of transverse polarizations in $B_{(s)}\to D^{*}V$ decay channels.

After a brief review of the muon $g-2$ status, we analyze the possibility that the present discrepancy between experiment and the standard model (SM) prediction may be due to hypothetical errors in the determination of the hadronic leading-order contribution to the latter. In particular, we show how an increase of the hadroproduction cross section in low-energy $e^{+}{e}^{-}$ collisions could bridge the muon $g-2$ discrepancy, leading however to a decrease on the electroweak upper bound on $M_H$, the SM Higgs boson mass. That bound is currently $M_H\lesssim 150\mathrm{GeV}$ (95% C.L.) based on the preliminary top quark mass $M_t=172.6(1.4)\mathrm{GeV}$ and the recent determination $\Delta {\alpha }_{\mathrm{had}}^{(5)}(M_Z)=0.02768(22)$, while the direct-search lower bound is $M_H>114.4\mathrm{GeV}$ (95% C.L.). By means of a detailed analysis we conclude that this solution of the muon $g-2$ discrepancy is unlikely in view of current experimental error estimates. However, if this turns out to be the solution, the 95% C.L. upper bound on $M_H$ is reduced to about 130 GeV which, in conjunction with the experimental lower bound, leaves a narrow window for the mass of this fundamental particle.

We show that in supersymmetric left-right models (SUSYLR), the upper bound on the lightest neutral Higgs mass can be appreciably higher than that in the minimal supersymmetric standard model (MSSM). The exact magnitude of the bound depends on the scale of parity restoration and can be 10–20 GeV above the MSSM bound if the mass of the right-handed $W_R$ is in the TeV range. An important implication of our result is that since SUSYLR models provide a simple realization of the seesaw mechanism for neutrino masses, measurement of the Higgs boson mass could provide an independent probe of a low seesaw scale.

We investigate the occurrence of ambiguities for the Lorentz-violating gravitational Chern-Simons term. It turns out that this term is accompanied by a coefficient depending on an undetermined parameter, due to an arbitrariness in the choice of the conserved current.

We consider a gauge-Higgs system on a fuzzy 2-sphere and study the topological structure of gauge configurations, when the $U(2)$ gauge symmetry is spontaneously broken to $U(1)\times U(1)$ by the vev of the Higgs field. The topology is classified by the index of the Dirac operator satisfying the Ginsparg-Wilson relation, which turns out to be a noncommutative analog of the topological charge introduced by ’t Hooft. It can be rewritten as a form whose commutative limit becomes the winding number of the Higgs field. We also study conditions which assure the validity of the formulation, and give a generalization of the admissibility condition. Finally we explicitly calculate the topological charge of a one-parameter family of configurations.

We evolve equal-mass, equal-spin black-hole binaries with specific spins of $a/m_H\sim 0.925$, the highest spins simulated thus far and nearly the largest possible for Bowen-York black holes, in a set of configurations with the spins counteraligned and pointing in the orbital plane, which maximizes the recoil velocities of the merger remnant, as well as a configuration where the two spins point in the same direction as the orbital angular momentum, which maximizes the orbital hangup effect and remnant spin. The coordinate radii of the individual apparent horizons in these cases are very small and the simulations require very high central resolutions ($h\sim M/320$). We find that these highly spinning holes reach a maximum recoil velocity of $\sim 3300\mathrm{km}{\mathrm{s}}^{-1}$ (the largest simulated so far) and, for the hangup configuration, a remnant spin of $a/m_H\sim 0.922$. These results are consistent with our previous predictions for the maximum recoil velocity of $\sim 4000\mathrm{km}{\mathrm{s}}^{-1}$ and remnant spin; the latter reinforcing the prediction that cosmic censorship is not violated by merging highly spinning black-hole binaries. We also numerically solve the initial data for, and evolve, a single maximal-Bowen-York-spin black hole, and confirm that the 3-metric has an $\mathcal{O}(r^{-2})$ singularity at the puncture, rather than the usual $\mathcal{O}(r^{-4})$ singularity seen for nonmaximal spins.

A holographic model is presented, which allows us to describe scalar hadrons with an arbitrary number of constituents.

A benchmark $CP$-violating supersymmetric scenario (known in the literature as “CPX-scenario”) is studied in the context of the Large Hadron Collider (LHC). It is shown that the LHC, with low to moderate accumulated luminosity, will be able to probe the existing “hole” in the $m_{h_1}\mathrm{\text{−}}\tan \beta$ plane, which cannot be ruled out by the Large Electron Positron Collider data. This can be done through associated production of Higgs bosons with top quark and top squark pairs leading to the signal $\mathrm{\text{dilepton}}+\le 5\mathrm{\text{jets}}(\mathrm{\text{including}}3b-\mathrm{\text{jets}})+\mathrm{\text{missing}}{p}_T$. Efficient discrimination of such a $CP$-violating supersymmetric scenario from other contending ones is also possible at the LHC with a moderate volume of data.

We calculate the total cross section for single charged slepton production in association with a top quark at hadron colliders in the baryon-triality (${\mathrm{B}}_3$) supersymmetric model. We compute event rates for the Fermilab Tevatron and CERN LHC. We study the signatures for different supersymmetric scenarios including neutralino and stau lightest supersymmetric particles. We perform a detailed analysis with basic cuts for the ${\mathrm{B}}_3$ operator ${\lambda }_{231}^{\prime }$ using Monte Carlo simulations to show that the signal can be distinguished from the background at the LHC. In particular, we employ the resulting lepton charge asymmetry.

This article presents the compatibility of experimental data from neutrino oscillation experiments with a high-$\Delta m^2$ two-neutrino oscillation hypothesis. Data is provided by the Bugey, Karlsruhe Rutherford Medium Energy Neutrino Experiment 2 (KARMEN2), Los Alamos Liquid Scintillator Neutrino Detector (LSND), and MiniBooNE experiments. The LSND, KARMEN2, and MiniBooNE results are 25.36% compatible within a two-neutrino oscillation hypothesis. However, the point of maximal compatibility is found in a region that is excluded by the Bugey data. A joint analysis of all four experiments, performed in the ${sin}^{2}2\theta \mathrm{vs}\Delta m^2$ region common to all data, finds a maximal compatibility of 3.94%. This result does not account for additions to the neutrino oscillation model from sources such as $CP$ violation or sterile neutrinos.

We report a search for the decay $B^0\to J/\psi \varphi$, using a sample of $657\times {10}^6$ $B\overline{B}$ pairs collected with the Belle detector at the ${\rm Y}(4S)$ resonance. No statistically significant signal is found and an upper limit for the branching fraction is determined to be $\mathcal{B}(B^0\to J/\psi \varphi )<9.4\times {10}^{-7}$ at 90% confidence level.