We study the big-bang nucleosynthesis (BBN) with the long-lived exotic particle, called $X$. If the lifetime of $X$ is longer than $\sim 0.1\sec$, its decay may cause nonthermal nuclear reactions during or after the BBN, altering the predictions of the standard BBN scenario. We pay particular attention to its hadronic decay modes and calculate the primordial abundances of the light elements. Using the result, we derive constraints on the primordial abundance of $X$. Compared to the previous studies, we have improved the following points in our analysis: The JETSET 7.4 Monte Carlo event generator is used to calculate the spectrum of hadrons produced by the decay of $X$; the evolution of the hadronic shower is studied taking into account the details of the energy-loss processes of the nuclei in the thermal bath; we have used the most recent observational constraints on the primordial abundances of the light elements; in order to estimate the uncertainties, we have performed the Monte Carlo simulation which includes the experimental errors of the cross sections and transferred energies. We will see that the nonthermal productions of D, ${}^3\mathrm{He}$, ${}^4\mathrm{He}$, and ${}^6\mathrm{Li}$ provide stringent upper bounds on the primordial abundance of a late-decaying particle, in particular, when the hadronic branching ratio of $X$ is sizable. We apply our results to the gravitino problem, and obtain an upper bound on the reheating temperature after inflation.

We study the lepton angular distributions in $B\to D^{(*)}\ell {\nu }_{\ell }$ decays. The lepton angular asymmetries in the decays with the general effective interactions are examined. We demonstrate that the asymmetries are sensitive to new physics with a right-handed quark current.

The $1/N_c$ expansion is formulated for the baryon wave function in terms of a specially constructed generating functional. The leading order of this $1/N_c$ expansion is universal for all low-lying baryons [including the $O(N_c^{-1})$ and $O(N_c^0)$ excited resonances] and for baryon-meson scattering states. A nonlinear evolution equation of Hamilton-Jacobi type is derived for the generating functional describing the baryon distribution amplitude in the large-$N_c$ limit. In the asymptotic regime this nonlinear equation is solved analytically. The anomalous dimensions of the leading-twist baryon operators diagonalizing the evolution are computed analytically up to the next-to-leading order of the $1/N_c$ expansion.

In this paper I show that it is possible to use Regge theory to constrain the initial parton distribution functions of a global Dokshitzer, Gribov, Lipatov, Altarelli, and Parisi (DGLAP) fit. In this approach, both quarks and gluons have the same high-energy behavior which may also be used to describe soft interactions. More precisely, I show that, if we parametrize the parton distributions with a triple-pole pomeron, i.e. like ${log}^2(1/x)$ at small $x$, at $Q^2=Q_0^2$ and evolve these distributions with the DGLAP equation, we can reproduce $F_2^p$, $F_2^d$, $F_2^n/F_2^p$, $F_2^{\nu N}$, and $x{F}_3^{\nu N}$ for $W^2\ge 12.5{\mathrm{GeV}}^2$. In this case, we obtain a new leading-order global QCD fit with a Regge-compatible initial condition. I shall also show that it is possible to use Regge theory to extend the parton distribution functions to small $Q^2$. This leads to a description of the structure functions over the whole $Q^2$ range based on Regge theory at low $Q^2$ and on QCD at large $Q^2$. Finally, I shall argue that, at large $Q^2$, the parton distribution functions obtained from DGLAP evolution and containing an essential singularity at $j=1$ can be approximated by a triple-pole pomeron behavior.

We present a new supersymmetric extension of the standard model. The model is constructed in warped space, with a unified bulk symmetry broken by boundary conditions on both the Planck and TeV branes. In the supersymmetric limit, the massless spectrum contains exotic colored particles along with the particle content of the minimal supersymmetric standard model (MSSM). Nevertheless, the model still reproduces the MSSM prediction for gauge coupling unification and does not suffer from a proton decay problem. The exotic states acquire masses from supersymmetry breaking, making the model completely viable, but there is still the possibility that these states will be detected at the LHC. The lightest of these states is most likely $A_5^{\mathrm{XY}}$, the fifth component of the gauge field associated with the broken unified symmetry. Because supersymmetry is broken on the $SU(5)$-violating TeV brane, the gaugino masses generated at the TeV scale are completely independent of one another. We explore some of the unusual features that the superparticle spectrum might have as a consequence.

We propose an electroweak model which is compatible with the UV insensitive anomaly-mediated supersymmetry breaking. The model is an extension of the next to minimal supersymmetric standard model (NMSSM) by adding vectorlike matter fields which can drive the soft scalar masses of the singlet Higgs field negative and the successful electroweak symmetry breaking is achieved. Viable parameter regions are found to preserve perturbativity of all the coupling constants up to the Planck scale. With this success, the model becomes a perfect candidate of physics beyond the standard model without the flavor changing neutral current and $CP$ problem. The cosmology is also quite interesting. The lightest neutralino is the wino which is a perfect cold dark matter candidate assuming the nonthermal production from the gravitino decay. There is no gravitino problem because it decays before the big-bang nucleosynthesis era, and thus the thermal leptogenesis works. The cosmological domain wall problem inherent in the NMSSM is absent since the $Z_3$ symmetry is broken by the QCD instanton effect in the presence of the vectorlike quarks. We also briefly comment on a possible solution to the strong $CP$ problem à la the Nelson-Barr mechanism.

We present a precise measurement of the standard model $CP$-violation parameter $\sin 2{\varphi }_1$, the direct $CP$ violation parameter $|\lambda |$, the lifetimes of charged and neutral $B$ mesons and their ratio, and the $B^0$-${\overline{B}}^0$ mixing parameter $\Delta m_d$ based on a sample of $152\times {10}^6$ $B\overline{B}$ pairs collected at the ${\rm Y}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. One of two $B$ mesons is fully reconstructed in a $CP$-eigenstate or a flavor-eigenstate decay channel. The flavor of the accompanying $B$ meson is identified from its decay products. From the distributions of the time interval between the two $B$ meson decay points, we obtain $\sin 2{\varphi }_1=0.728\pm 0.056(\mathrm{stat})\pm 0.023(\mathrm{syst})$, $|\lambda |=1.007\pm 0.041(\mathrm{stat})\pm 0.033(\mathrm{syst})$, ${\tau }_{B^0}=[1.534\pm 0.008(\mathrm{stat})\pm 0.010(\mathrm{syst})]\mathrm{ps}$, ${\tau }_{B^{+}}=[1.635\pm 0.011(\mathrm{stat})\pm 0.011(\mathrm{syst})]\mathrm{ps}$, ${\tau }_{B^{+}}/{\tau }_{B^0}=1.066\pm 0.008(\mathrm{stat})\pm 0.008(\mathrm{syst})$ and $\Delta m_d=[0.511\pm 0.005(\mathrm{stat})\pm 0.006{(\mathrm{syst})]\mathrm{ps}}^{-1}$. The results for $\sin 2{\varphi }_1$ and $|\lambda |$ are consistent with the standard model expectations. The significance of the observed deviation from unity in the lifetime ratio exceeds 5 standard deviations.

We investigate a deformed matrix model of type 0A theory related to supersymmetric Witten’s black hole in two-dimensions, a generalization of bosonic model suggested by Kazakov et al. We find a free field realization of the partition function of the matrix model, which includes Ramond-Ramond perturbations in the type 0A theory. In a simple case, the partition function is factorized into two determinants, which are given by $\tau$ function of an integrable system. We work out the genus expansion of the partition function. Holographic relation with the supersymmetric Witten’s black hole is checked by Wilson line computation. The corresponding partition function of the matrix model exhibits a singular behavior, which is interpreted as the point of enhanced $\mathcal{N}=2$ world sheet supersymmetry. An interesting relation between the deformed matrix model and topological string on a $Z_2$ orbifold of conifold is found.

We propose stringy hadronic amplitudes that combine some of the features of sister trajectories and running tension. By summing over string amplitudes with varying Regge trajectories that have integer tension and converging intercept, we obtain parton hard-scattering and Regge soft-scattering behaviors, while preserving discrete poles in both momentum and angular momentum.

We study vortex-type solutions in a $(4+1)$-dimensional Einstein-Yang-Mills-SU(2) model. Assuming all fields to be independent on the extra coordinate, these solutions correspond in a four-dimensional picture to axially symmetric multimonopoles, respectively, monopole-antimonopole solutions. By boosting the five-dimensional purely magnetic solutions, we find new configurations which in four dimensions represent rotating regular non-Abelian solutions with an additional electric charge.

We investigate a condensed matter “black hole” analog, taking the Gross-Pitaevskii (GP) equation as a starting point. The linearized GP equation corresponds to a wave equation on a black hole background, giving quasinormal modes under some appropriate conditions. We suggest that we can know the detailed characters and corresponding geometrical information about the acoustic black hole by observing quasinormal ringdown waves in the low temperature condensed matters.

We consider black-string-type solutions in five-dimensional Einstein-Gauss-Bonnet gravity. Numerically constructed solutions under static, axially symmetric and translationally invariant metric ansatz are presented. The solutions are specified by two asymptotic charges: mass of a black string and a scalar charge associated with the radion part of the metric. Regular black string solutions are found if and only if the two charges satisfy a fine-tuned relation, and otherwise the spacetime develops a singular event horizon or a naked singularity. We can also generate bubble solutions from the black strings by using a double Wick rotation.

Here, we report pp waves configurations of three-dimensional gravity for which a scalar field nonminimally coupled to them acts as a source. In absence of self-interaction the solutions are gravitational plane waves with a profile fixed in terms of the scalar wave. In the self-interacting case, only power-law potentials parameterized by the nonminimal coupling constant are allowed by the field equations. In contrast with the free case the self-interacting scalar field does not behave like a wave since it depends only on the wave-front coordinate. We address the same problem when gravitation is governed by topologically massive gravity and the source is a free scalar field. From the pp waves derived in this case, we obtain at the zero topological mass limit, new pp waves solutions of conformal gravity for any arbitrary value of the nonminimal coupling parameter. Finally, we extend these solutions to the self-interacting case of conformal gravity.

Annihilation of extremely energetic cosmic neutrinos on the relic-neutrino background can give rise to absorption lines at energies corresponding to formation of the electroweak gauge boson $Z^0$. The positions of the absorption dips are set by the masses of the relic neutrinos. Suitably intense sources of extremely energetic (${10}^{21}–{10}^{25}\mathrm{\text{−}}\mathrm{eV}$) cosmic neutrinos might therefore enable the determination of the absolute neutrino masses and the flavor composition of the mass eigenstates. Several factors—other than neutrino mass and composition—distort the absorption lines, however. We analyze the influence of the time evolution of the relic-neutrino density and the consequences of neutrino decay. We consider the sensitivity of the line shape to the age and character of extremely energetic neutrino sources, and to the thermal history of the Universe, reflected in the expansion rate. We take into account Fermi motion arising from the thermal distribution of the relic-neutrino gas. We also note the implications of Dirac vs. Majorana relics, and briefly consider unconventional neutrino histories. We ask what kinds of external information would enhance the potential of cosmic-neutrino absorption spectroscopy, and estimate the sensitivity required to make the technique a reality.

The minimal supersymmetric extension of the standard model (MSSM) can provide the correct neutralino relic abundance and baryon number asymmetry of the universe. Both may be efficiently generated in the presence of $CP$ violating phases, light charginos and neutralinos, and a light top squark. Because of the coannihilation of the neutralino with the light stop, we find a large region of parameter space in which the neutralino relic density is consistent with WMAP and SDSS data. We perform a detailed study of the additional constraints induced when $CP$ violating phases, consistent with the ones required for baryogenesis, are included. We explore the possible tests of this scenario from present and future electron electric dipole moment (EDM) measurements, direct neutralino detection experiments, collider searches and the $b\to s\gamma$ decay rate. We find that the EDM constraints are quite severe and that electron EDM experiments, together with stop searches at the Tevatron and Higgs searches at the LHC, will provide a definite test of our scenario of electroweak baryogenesis in the next few years.

Supersymmetric extensions of the standard model exhibiting bilinear $R$-parity violation can generate naturally the observed neutrino mass spectrum as well as mixings. One interesting feature of these scenarios is that the lightest supersymmetric particle (LSP) is unstable, with several of its decay properties predicted in terms of neutrino mixing angles. A smoking gun of this model in colliders is the presence of displaced vertices due to LSP decays in large parts of the parameter space. In this work we focus on the simplest model of this type that comes from minimal supergravity with universal $R$-parity conserving soft breaking of supersymmetry augmented with bilinear $R$-parity breaking terms at the electroweak scale (RmSUGRA). We evaluate the potential of the Fermilab Tevatron to probe the RmSUGRA parameters through the analysis of events possessing two displaced vertices stemming from LSP decays. We show that requiring two displaced vertices in the events leads to a reach in $m_{1/2}$ twice the one in the usual multilepton signals in a large fraction of the parameter space.

The article contains general formulas for the production of $J=3/2$ resonances by neutrinos and antineutrinos. It specializes to the $P_{33}(1232)$ resonance whose form factors are determined by theory and experiment and then are compared with experimental results at low and high energies. It is shown that the minimum in the low $Q^2$ region is a consequence of a combined effect from the vanishing of the vector form factors, the muon mass and Pauli blocking. Several improvements for the future investigations are suggested.

The geometric distribution of high-energy hadrons $\ge 100\mathrm{GeV}$ in shower cores measured with the KASCADE calorimeter is analyzed. The data are checked for sensitivity to hadronic interaction features and indications of new physics as discussed in the literature. The angular correlation of the most energetic hadrons and, in particular, the fraction of events with hadrons being aligned are quantified by means of the commonly used parameter ${\lambda }_4$. The analysis shows that the observed ${\lambda }_4$ distribution is compatible with that predicted by simulations and is not linked to an angular correlation from hadronic jet production at high energy. Another parameter, $d_4^{\max }$, describing distances between hadrons measured in the detector, is found to be sensitive both to the transverse momenta in secondary hadron production and the primary particle type. Transverse momenta in high-energy hadron interactions differing by a factor two or more from what is assumed in the standard simulations are disfavored by the measured $d_4^{\max }$ distribution.

We analyze $13.8\mathrm{f}{\mathrm{b}}^{-1}$ of the integrated $e^{+}{e}^{-}$ luminosity collected at 10.6 GeV center-of-mass energy with the CLEO II and CLEO II.V detectors to study exclusive two-photon production of hadrons with masses below $1.7\mathrm{GeV}/{\mathrm{c}}^2$ decaying into the $K_S^0{K}^{\pm }{\pi }^{\mp }$ final state. We observe two statistically significant enhancements in the $\eta (1475)$ mass region. These enhancements have large transverse momentum which rules them out as being due to pseudoscalar resonances but is consistent with the production of axial-vector mesons. We use tagged two-photon events to study the properties of the observed enhancements and associate them with the production of $f_1(1285)$ and $f_1(1420)$. Our nonobservation of $\eta (1475)$ is inconsistent by more than 2 standard deviations with the first observation of this resonance in two-photon collisions by the L3 experiment. We present our estimates for 90% confidence level upper limits on the products of two-photon partial widths of light pseudoscalar hadrons and their branching fractions into $K_S^0({\pi }^{+}{\pi }^{-})K^{\pm }{\pi }^{\mp }$.