In split supersymmetry, the supersymmetric scalar particles are all very heavy, at least at the order of ${10}^9$ GeV, but the gauginos, Higgsinos, and one of the neutral Higgs bosons remain below a TeV. Here we further split the split supersymmetry by taking the Higgsino mass parameter $\mu$ to be very large. In this case, the $\mu$ problem is avoided and we keep the wino as a dark matter candidate. A crude gauge-coupling unification is still preserved. Dark matter signals and collider phenomenology are discussed in this $\mu$-split SUSY scenario. The most interesting dark matter signal is the annihilation into monochromatic photons. In colliders, chargino-pair and the associated chargino-neutralino production cross sections have a certain ratio due to gauge couplings.

We consider a phenomenologically viable $SO(10)$ grand unification model of the unification scale $M_G$ around ${10}^{16}\mathrm{GeV}$ which reproduces the minimal supersymmetric standard model at low energy and allows perturbative calculations up to the Planck scale $M_P$ or the string scale $M_{st}$. Both requirements strongly restrict a choice of Higgs representations in a model. We propose a simple $SO(10)$ model with a set of Higgs representations $\{2\times \mathbf{10}+\overline{\mathbf{16}}+\mathbf{16}+\mathbf{45}\}$ and show its phenomenological viability. This model can indeed reproduce the low-energy experimental data relating the charged fermion masses and mixings. Neutrino oscillation data can be consistently incorporated in the model, leading to the right-handed neutrino mass scale $M_R\simeq M_G^2/M_P$. Furthermore, there exists a parameter region which results the proton lifetime consistent with the experimental results.

This paper presents a first study of the decay constants of the charged, or flavor-off-diagonal, pseudoscalar mesons to two loops for three flavors of sea quarks, in partially quenched chiral perturbation theory ($\mathrm{PQ}\chi \mathrm{PT}$). Explicit analytical expressions up to $\mathcal{O}(p^6)$ in the momentum expansion are given. The calculations have been performed within the supersymmetric formulation of $\mathrm{PQ}\chi \mathrm{PT}$. We also present some numerical results to indicate the size of the corrections.

We review critically the predictions of pentaquarks in the quark model, in particular, those based on the flavor-spin-dependent (Glozman-Riska) hyperfine interaction and the color-spin (one-gluon-exchange Fermi-Breit) one. We include the antiquark interactions and find that: (1) the exotic SU(3) multiplets are not substantialy affected in the flavor-spin model, whereas some of the nonexotic multiplets are; and (2) the variational upper bound on the ${\Xi }^{--}-{\Theta }^{+}$ mass difference in the color-spin hyperfine interaction model is substantially reduced. This leads us to the $U_A(1)$ symmetry breaking Kobayashi-Kondo-Maskawa-’tHooft interaction. We discuss some of its phenomenological consequences for pentaquarks.

The recent observations of sizable transverse fractions of $\overline{B}\to \varphi {\overline{K}}^{*}$ may hint for the existence of new physics. We analyze all possible new-physics four-quark operators and find that two classes of new-physics operators could offer resolutions to the $\overline{B}\to \varphi {\overline{K}}^{*}$ polarization anomaly. The operators in the first class have structures $(1-{\gamma }_5)\otimes (1-{\gamma }_5)$, $\sigma (1-{\gamma }_5)\otimes \sigma (1-{\gamma }_5)$, and in the second class $(1+{\gamma }_5)\otimes (1+{\gamma }_5)$, $\sigma (1+{\gamma }_5)\otimes \sigma (1+{\gamma }_5)$. For each class, the new-physics effects can be lumped into a single parameter. Two possible experimental results of polarization phases, $\arg (A_{\perp })-\arg (A_{\parallel })\approx \pi$ or 0, originating from the phase ambiguity in data, could be separately accounted for by our two new-physics scenarios: the first (second) scenario with the first (second) class new-physics operators. The consistency between the data and our new-physics analysis suggests a small new-physics weak phase, together with a large(r) strong phase. We obtain sizable transverse fractions ${\Lambda }_{\parallel \parallel }+{\Lambda }_{\perp \perp }\approx {\Lambda }_{00}$, in accordance with the observations. We find ${\Lambda }_{\parallel \parallel }\simeq 0.8{\Lambda }_{\perp \perp }$ in the first scenario but ${\Lambda }_{\parallel \parallel }\gtrsim {\Lambda }_{\perp \perp }$ in the second scenario. We discuss the impact of the new-physics weak phase on observations.

We have measured the azimuthal angular correlation of $b\overline{b}$ production, using $86.5\mathrm{p}{\mathrm{b}}^{-1}$ of data collected by Collider Detector at Fermilab (CDF) in $p\overline{p}$ collisions at $\sqrt{s}=1.8\mathrm{TeV}$ during 1994–1995. In high-energy $p\overline{p}$ collisions, such as at the Tevatron, $b\overline{b}$ production can be schematically categorized into three mechanisms. The leading-order (LO) process is “flavor creation,” where both $b$ and $\overline{b}$ quarks substantially participate in the hard scattering and result in a distinct back-to-back signal in final state. The “flavor excitation” and the “gluon splitting” processes, which appear at next-leading-order (NLO), are known to make a comparable contribution to total $b\overline{b}$ cross section, while providing very different opening angle distributions from the LO process. An azimuthal opening angle between bottom and antibottom, $\Delta \varphi$, has been used for the correlation measurement to probe the interaction creating $b\overline{b}$ pairs. The $\Delta \varphi$ distribution has been obtained from two different methods. One method measures the $\Delta \varphi$ between bottom hadrons using events with two reconstructed secondary vertex tags. The other method uses $b\overline{b}\to (J/\psi X)(\ell X^{\prime })$ events, where the charged lepton ($\ell$) is an electron ($e$) or a muon ($\mu$), to measure $\Delta \varphi$ between bottom quarks. The $b\overline{b}$ purity is determined as a function of $\Delta \varphi$ by fitting the decay length of the $J/\psi$ and the impact parameter of the $\ell$. Both methods quantify the contribution from higher-order production mechanisms by the fraction of the $b\overline{b}$ pairs produced in the same azimuthal hemisphere, $f_{\mathrm{toward}}$. The measured $f_{\mathrm{toward}}$ values are consistent with both parton shower Monte Carlo and NLO QCD predictions.

This work is devoted to the study of the $CP$-breaking dynamics in QCD, at finite $\theta$-angle. By working in the semiclassical limit, in which the topology of the vacuum is clustered around instantons and anti-instantons, we show that the quantum fluctuations of the $\theta$-vacuum generate an effective flavor-dependent repulsion between matter and antimatter. As a consequence, during the tunneling between the degenerate classical vacua, quarks and antiquarks in a neutron migrate in opposite directions, giving rise to an oscillating electric dipole moment. We discuss a possible phenomenological implication of this effect.

We report on a search for the $CP$ asymmetry in the singly Cabibbo-suppressed decays $D^{+}\to K^{-}{K}^{+}{\pi }^{+}$ and in the resonant decays $D^{+}\to \varphi {\pi }^{+}$ and $D^{+}\to {\overline{K}}^{*0}{K}^{+}$ based on a data sample of $79.9{\mathrm{fb}}^{-1}$ recorded by the BABAR detector. We use the Cabibbo-favored $D_s^{+}\to K^{-}{K}^{+}{\pi }^{+}$ branching fraction as normalization in the measurements to reduce systematic uncertainties. The $CP$ asymmetries obtained are $A_{CP}(K^{-}{K}^{+}{\pi }^{\pm })=(1.4\pm 1.0(\mathrm{stat})\pm 0.8(\mathrm{syst}))\times {10}^{-2}$, $A_{CP}(\varphi {\pi }^{\pm })=(0.2\pm 1.5(\mathrm{stat})\pm 0.6(\mathrm{syst}))\times {10}^{-2}$, and $A_{CP}({\overline{K}}^{*0}{K}^{\pm })=(0.9\pm 1.7(\mathrm{stat})\pm 0.7(\mathrm{syst}))\times {10}^{-2}$. The relative branching fraction $\Gamma (D^{+}\to K^{-}{K}^{+}{\pi }^{+})/\Gamma (D^{+}\to K^{-}{\pi }^{+}{\pi }^{+})$ is also measured and is found to be $(10.7\pm 0.1(\mathrm{stat})\pm 0.2(\mathrm{syst}))\times {10}^{-2}$.

S-matrices can be written Lorentz covariantly in terms of free field strengths for vector states, allowing arbitrary gauge choices. In string theory the vertex operators can be chosen so this gauge invariance is automatic. As examples we give four-vector (super)string tree amplitudes in this form, and find the field theory actions that give the first three orders in the slope.

The problem of physical process version of the first law of black hole thermodynamics for charged rotating black hole in $n$-dimensional gravity is elaborated. The formulas for the first order variations of mass, angular momentum and canonical energy in Einstein $(n-2)$-gauge form field theory are derived. These variations are expressed by means of the perturbed matter energy momentum tensor and charge matter current density.

The complete one-loop radiative corrections to third-generation scalar fermions into gauge bosons $Z$ and $W^{\pm }$ is considered. We focus on ${\tilde{f}}_2\to Z{\tilde{f}}_1$ and ${\tilde{f}}_i\to W^{\pm }{\tilde{f}}_j^{\prime }$, $f,f^{\prime }=t,b$. We include SUSY-QCD, QED, and full electroweak corrections. It is found that the electroweak corrections can be of the same order as the SUSY-QCD corrections. The two sets of corrections interfere destructively in some region of parameter space. The full one-loop correction can reach 10% in some supergravity scenario, while in model independent analysis like general the minimal supersymmetric standard model, the one-loop correction can reach 20% for large $\tan \beta$ and large trilinear soft breaking terms $A_b$.

We study the helicity and chirality transitions of a high-energy neutrino propagating in a Schwarzschild space-time background. Using both traditional Schwarzschild and isotropic spherical coordinates, we derive an ultrarelativistic approximation of the Dirac Hamiltonian to first-order in the neutrino’s rest mass, via a generalization of the Cini-Touschek transformation that incorporates noninertial frame effects due to the noncommutative nature of the momentum states in curvilinear coordinates. Under general conditions, we show that neutrino’s helicity is not a constant of the motion in the massless limit due to space-time curvature, while the chirality transition rate still retains an overall dependence on mass. We show that the chirality transition rate generally depends on the zeroth-order component of the neutrino’s helicity transition rate under the Cini-Touschek transformation. It is also shown that the chiral current for high-energy neutrinos is altered by corrections due to curvature and frame-dependent effects, but should have no significant bearing on the chiral anomaly in curved space-time. We determine the upper bound for helicity and chirality transitions near the event horizon of a black hole. The special case of a weak-field approximation is also considered, which includes the gravitational analogue of Berry’s phase first proposed by Cai and Papini. Finally, we propose a method for estimating the absolute neutrino mass and the number of right-handed chiral states from the expectation values of the helicity and chirality transition rates in the weak-field limit.

We present a formalism to study the metric perturbations of the Schwarzschild spacetime. The formalism is gauge invariant, and it is also covariant under two-dimensional coordinate transformations that leave the angular coordinates unchanged. The formalism is applied to the typical problem of calculating the gravitational waves produced by material sources moving in the Schwarzschild spacetime. We examine the radiation escaping to future null infinity as well as the radiation crossing the event horizon. The waveforms, the energy radiated, and the angular-momentum radiated can all be expressed in terms of two gauge-invariant scalar functions that satisfy one-dimensional wave equations. The first is the Zerilli-Moncrief function, which satisfies the Zerilli equation, and which represents the even-parity sector of the perturbation. The second is the Cunningham-Price-Moncrief function, which satisfies the Regge-Wheeler equation, and which represents the odd-parity sector of the perturbation. The covariant forms of these wave equations are presented here, complete with covariant source terms that are derived from the stress-energy tensor of the matter responsible for the perturbation.

In this paper, we extend the idea that the spectrum of Hawking radiation can reveal valuable information on a number of parameters that characterize a particular black hole background—such as the dimensionality of spacetime and the value of coupling constants—to gain information on another important aspect: the curvature of spacetime. We investigate the emission of Hawking radiation from a $D$-dimensional Schwarzschild–de Sitter black hole emitted in the form of scalar fields, and employ both analytical and numerical techniques to calculate greybody factors and differential energy emission rates on the brane and in the bulk. The energy emission rate of the black hole is significantly enhanced in the high-energy regime with the number of spacelike dimensions. On the other hand, in the low-energy part of the spectrum, it is the cosmological constant that leaves a clear footprint, through a characteristic, constant emission rate of ultrasoft quanta determined by the values of black hole and cosmological horizons. Our results are applicable to “small” black holes arising in theories with an arbitrary number and size of extra dimensions, as well as to pure 4-dimensional primordial black holes, embedded in a de Sitter spacetime.

We investigate the dependence of the Yang-Mills wave functional in Coulomb gauge on the Faddeev-Popov determinant. We use a Gaussian wave functional multiplied by an arbitrary power of the Faddeev-Popov determinant. We show, that within the resummation of one-loop diagrams the stationary vacuum energy is independent of the power of the Faddeev-Popov determinant and, furthermore, the wave functional becomes field independent in the infrared, describing a stochastic vacuum. Our investigations show, that the infrared limit is rather robust against details of the variational Ansatz for the Yang-Mills wave functional. The infrared limit is exclusively determined by the divergence of the Faddeev-Popov determinant at the Gribov horizon.

Resummation, i.e. reorganization of perturbative series, can result in an inconsistent perturbation theory, unless the counterterms are reorganized in an appropriate way. In this paper two methods are presented for resummation of counterterms: one is a direct method where the necessary counterterms are constructed order by order; the other is a general one, based on renormalization group arguments. Using the ${\Phi }^4$ model, we demonstrate on one hand that, in mass-independent schemes, mass resummation can be performed by gap equations renormalized prior to the substitution of the resummed mass for its argument. On the other hand it is shown that any (momentum-independent) form of mass and coupling constant resummation is compatible with renormalization, and one can explicitly construct the corresponding counterterms.

We give a Hamiltonian analysis of the asymptotically flat spherically symmetric system of gravity coupled to a scalar field. This $1+1$ dimensional field theory may be viewed as the “standard model” for studying black hole physics. Our analysis is adapted to the flat slice Painleve-Gullstrand coordinates. We give a Hamiltonian action principle for this system, which yields an asymptotic mass formula. We then perform a time gauge fixing that gives a Hamiltonian as the integral of a local density. The Hamiltonian takes a relatively simple form compared to earlier work in Schwarzschild gauge, and therefore provides a setting amenable to full quantization.

We revisit some questions in supersymmetric hybrid inflation. We analyze the amount of fine-tuning required in various models, the problem of decay at the end of inflation and the generation of baryons after inflation. We find that the most natural setting for hybrid inflation is in supersymmetric models with nonrenormalizable couplings. Furthermore, we argue that almost inevitably, one of the fields involved is a modulus, with Planck scale variation. The resulting moduli problem can be solved in two ways: either by a massive modulus (which requires some fine-tuning), or an enhanced symmetry point, in which the moduli becomes strongly coupled to the standard model. Various possibilities for baryon production are discussed.

We investigate the cosmological perturbations of the brane-induced (Dvali-Gabadadze-Porrati) model which exhibits a van Dam-Veltman-Zakharov (vDVZ) discontinuity when linearized over a Minkowski background. We show that the linear brane scalar cosmological perturbations over an arbitrary Friedmann-Lemaître-Robertson-Walker (FLRW) space-time have a well defined limit when the radius of transition between 4D and 5D gravity is sent to infinity with respect to the background Hubble radius. This radius of transition plays for the brane-induced gravity model a rôle equivalent to the Compton wavelength of the graviton in a Pauli-Fierz theory, as far as the vDVZ discontinuity is concerned. This well defined limit is shown to obey the linearized 4D Einstein’s equations whenever the Hubble factor is nonvanishing. This shows the disappearance of the vDVZ discontinuity for general FLRW background, and extends the previously know result for maximally-symmetric space-times of nonvanishing curvature. Our reasoning is valid for matter with simple equation of state such as a scalar field, or a perfect fluid with adiabatic perturbations, and involves to distinguish between space-times with a vanishing scalar curvature and space-times with a nonvanishing one. We also discuss the validity of the linear perturbation theory, in particular, for those FLRW space-times where the Ricci scalar is vanishing only on a set of zero measure. In those cases, we argue that the linear perturbation theory breaks down when the Ricci scalar vanishes (and the radius of transition is sent to infinity), in a way similar to what has been found to occur around sources on a Minkowski background.

We study the improvement of staggered fermions using hypercubically smeared links. We calculate the strange quark mass and the kaon $B$ parameter, $B_K$, in quenched QCD on a ${16}^3\times 64$ lattice at $\beta =6.0$. We find $m_s(\overline{\mathrm{MS}},2\mathrm{GeV})=101.2\pm 1.3\pm 4\mathrm{MeV}$ and $B_K(\overline{\mathrm{MS}},2\mathrm{GeV})=0.578\pm 0.018\pm 0.042$, where the first error is from statistics and fitting, and the second from using one-loop matching factors. The scale ($1/a=1.95\mathrm{GeV}$) is set by $M_{\rho }$, and $m_s$ is determined using the kaon mass. Comparing to quenched results obtained using unimproved staggered fermions and other discretizations, we argue that the size of discretization errors in $B_K$ is substantially reduced by improvement.