Showing papers in "Progress of Theoretical Physics in 2009"

Large Non-Gaussianity from Multi-Brid Inflation

Abstract: A model of multi-component hybrid inflation, dubbed multi-brid inflation, in which various observable quantities including the non-Gaussianity parameter fNL can be analytically calculated was proposed recently. In particular, for a two-brid inflation model with an exponential potential and the condition that the end of inflation is an ellipse in the field space, it was found that, while keeping the other observational quantities within the range consistent with observations, large non-Gaussianity is possible for certain inflationary trajectories, provided that the ratio of the two masses is large. One might question whether the resulting large non-Gaussianity is specific to this particular form of the potential and the condition for the end of inflation. In this paper, we consider a model of multi-brid inflation with a potential given by an exponential function of terms quadratic in the scalar field components. We also consider a more general class of ellipses for the end of inflation than those studied previously. Then, focusing on the case of two-brid inflation, we find that large non-Gaussianity is possible in the present model even for the equal-mass case. Then by tuning the model parameters, we find that there exist models for which both the non-Gaussianity and the tensor-to-scalar ratio are large enough to be detected in the very near future. Subject Index: 440

Higher-Derivative Corrections to the Asymptotic Virasoro Symmetry of 4d Extremal Black Holes

Abstract: We study the asymptotic Virasoro symmetry which acts on the near-horizon region of extremal four-dimensional black hole solutions of gravity theories with higher-derivative corrections, following the recently proposed Kerr/CFT correspondence. We demonstrate that its central charge correctly reproduces the entropy formula of Iyer-Wald, once the boundary terms in the symplectic structure are carefully chosen.

Rotating Black Hole in Extended Chern-Simons Modified Gravity

Abstract: We investigate a slowly rotating black hole in four-dimensional extended Chern-Simons modified gravity. We obtain an approximate solution that reduces to the Kerr solution when a coupling constant vanishes. The Chern-Simons correction effectively reduces the frame-dragging effect around a black hole in comparison with that of the Kerr solution. Subject Index: 420, 453

On Unitarity of Massive Gravity in Three Dimensions

Abstract: We examine a unitarity of a particular higher-derivative extension of general relativity in three space-time dimensions, which has been recently shown to be equivalent to the Pauli-Fierz massive gravity at the linearized approximation level, and explore a possibility of generalizing the model to higher space-time dimensions. We find that the model in three dimensions is indeed unitary in the tree-level, but the corresponding model in higher dimensions is not so due to the appearance of non-unitary massless spin-2 modes.

Decaying Hidden Gauge Boson and the PAMELA and ATIC/PPB-BETS Anomalies

Abstract: We show that the PAMELA anomaly in the positron fraction as well as the ATIC/PPBBETS excesses in the e − +e + flux are simultaneously explained in our scenario that a hidden U (1)H gauge boson constitutes dark matter of the Universe and decays into the standardmodel particles through a kinetic mixing with an U (1)B−L gauge boson. Interestingly, the

Influence on Observation from IR Divergence during Inflation. I.

Abstract: We propose a way to regularize the fluctuations generated during inflation, whose infrared (IR) corrections diverge logarithmically. In the case of a single-field inflation model, recently, we have proposed a solution to the IR divergence problem. There, we introduced new perturbative variables that better mimic actual observable fluctuations, and proved the regularity of correlation functions with respect to these variables. In this paper, we extend our previous discussions to a multi-field inflation model. We show that, as long as we consider the case that the nonlinear interaction acts for a finite duration, observable fluctuations are also free from IR divergences in the multi-field model. In contrast to the single-field model, to discuss observables, we need to take into account the effects of quantum decoherence, which pick up a unique history of the universe from various possibilities contained in an initial quantum state set naturally in the early stage of the universe.

A Holographic Dual of Bjorken Flow

Abstract: We propose a consistent setup for a holographic dual of Bjorken flow of strongly coupled large-Nc N = 4 SYM-theory plasma. We employ Eddington-Finkelstein type coordinates for the dual geometry, and we propose a late-time expansion there. We construct the dual geometry order by order, and we show that the transport coefficients are determined by the regularity of the geometry. We also show that the dual geometry has an apparent horizon hence an event horizon, which covers the singularity at the origin. We prove that the dual geometry is regular at all orders under an appropriate choice of the transport coefficients. Our model is a concrete well-defined example of time-dependent AdS/CFT. Subject Index: 121, 231, 451

Nuclear Force from String Theory

Abstract: We compute the nuclear force in a holographic model of QCD on the basis of a D4-D8 brane configuration in type IIA string theory. The repulsive core of nucleons is important in nuclear physics, but its origin has not been well understood in strongly coupled QCD. We find that the string theory via gauge/string duality deduces this repulsive core at a short distance between nucleons. Since baryons in the model are realized as solitons given by Yang-Mills instanton configuration on flavor D8-branes, ADHM construction of two instantons probes well the nucleon interaction at short scale, which provides the nuclear force quantitatively. We obtain a central force, as well as a tensor force, which is strongly repulsive as suggested in experiments and lattice results. In particular, the nucleon-nucleon potential V (r) (as a function of the distance) scales as r−2, which is peculiar to the holographic model. We compare our results with the one-boson exchange model using the nucleon-nucleon-meson coupling obtained in our previous paper [K. Hashimoto, T. Sakai and S. Sugimoto, Prog. Theor. Phys. 120 (2008), 1093, arXiv:0806.3122].

An Efficient Numerical Method for Computing Gravitational Waves Induced by a Particle Moving on Eccentric Inclined Orbits around a Kerr Black Hole

Abstract: We develop a numerical code to compute gravitational waves induced by a particle moving on eccentric inclined orbits around a Kerr black hole. For such systems, the black hole perturbation method is applicable. The gravitational waves can be evaluated by solving the Teukolsky equation with a point like source term, which is computed from the stress-energy tensor of a test particle moving on generic bound geodesic orbits. In our previous papers, we computed the homogeneous solutions of the Teukolsky equation using a formalism developed by Mano, Suzuki and Takasugi and showed that we could compute gravitational waves efficiently and very accurately in the case of circular orbits on the equatorial plane. Here, we apply this method to eccentric inclined orbits. The geodesics around a Kerr black hole have three constants of motion: energy, angular momentum and the Carter constant. We compute the rates of change of the Carter constant as well as those of energy and angular momentum. This is the first time that the rate of change of the Carter constant has been evaluated accurately. We also treat the case of highly eccentric orbits with e = 0.9. To confirm the accuracy of our codes, several tests are performed. We find that the accuracy is only limited by the truncation of -, kand n-modes, where is the index of the spin-weighted spheroidal harmonics, and n and k are the harmonics of the radial and polar motion, respectively. When we set the maximum of to 20, we obtain a relative accuracy of 10−5 even in the highly eccentric case of e = 0.9. The accuracy is better for lower eccentricity. Our numerical code is expected to be useful for computing templates of the extreme mass ratio inspirals, which is one of the main targets of the Laser Interferometer Space Antenna (LISA).

S4 Flavor Symmetry of Quarks and Leptons in SU(5) GUT

Abstract: We present an S4 flavor model to unify quarks and leptons in the framework of the SU(5) GUT. Three generations of 5-plets in SU(5) are assigned to 31 of S4, while the first and second generations of 10-plets in SU(5) are assigned to 2 of S4, and the third generation of 10-plets is assigned to 11 of S4. Right-handed neutrinos are also assigned to 2 for the first and second generations and to 11 for the third generation. By considering the vacuum alignments of relevant gauge singlet scalars, we predict the quark mixing as well as the tribimaximal mixing of neutrino flavors. In particular, the Cabbibo angle is predicted to be 15 ◦ in the limit of the vacuum alignment. We can improve the model to predict observed CKM mixing angles as well as the nonvanishing Ue3 of the neutrino flavor mixing. Subject Index: 140, 154

Spherical Deformation for One-Dimensional Quantum Systems

Abstract: System-size dependence of the ground-state energy E is investigated for N -site onedimensional (1D) quantum systems with open boundary condition, where the interaction strength decreases towards the both ends of the system. For the spinless Fermions on the 1D lattice we have considered, it is shown that the finite-size correction to the energy per site, which is defined as E/N − limN→∞ E/N , is of the order of 1/N when the reduction factor of the interaction is expressed by a sinusoidal function. We discuss the origin of this fast convergence from the viewpoint of the spherical geometry.

Chern-Simons Theories and Wrapped M-Branes in Their Gravity Duals

Abstract: We investigate a class of N = 4 quiver Chern-Simons theories and their gravity duals. We define the group of fractional D3-brane charges in a type IIB brane setup with taking account of D3-brane creation due to Hanany-Witten effect, and confirm that it agrees with the 3-cycle homology of the dual geometry, which describes the charges of fractional M2branes, M5-branes wrapped on 3-cycles. The relation between the fractional brane charge and the torsion of the three-form potential field is partially established. We also discuss the duality between baryonic operators in the Chern-Simons theories and M5-branes wrapped on 5-cycles in the dual geometries. The degeneracy and the conformal dimension of the operators are reproduced on the gravity side. We also comment on the relation between wrapped M2-branes and monopole operators. The baryonic operators we consider are not gauge invariant. We argue that the gauge invariance cannot be imposed on all the operators corresponding to wrapped M-branes in AdS4/CFT3 correspondence.

Quantum Three-Body Calculation of the Nonresonant Triple-α Reaction Rate at Low Temperatures

Abstract: Triple-α reaction rate is re-evaluated by directly solving the three-body Schrodinger equation. The resonant and nonresonant processes are treated on the same footing using the continuum-discretized coupled-channels method for three-body scattering. An accurate de- scription of the α-α nonresonant states significantly quenches the Coulomb barrier between the first two α-particles and the third α-particle. Consequently, the α-α nonresonant contin- uum states below the resonance at 92.04 keV, i.e., the ground state of 8 Be, give a markedly larger contribution at low temperatures than that reported in previous studies. We show that Nomoto's method for three-body nonresonant capture processes, which is adopted in the NACRE compilation and many other studies, is a crude approximation of the accurate quantum three-body model calculation. We find an increase in triple-α reaction rate by about 20 orders of magnitude around 10 7 K compared with the rate of NACRE. Subject Index: 240, 481

Crum's Theorem for `Discrete' Quantum Mechanics

Abstract: In one-dimensional quantum mechanics, or the Sturm-Liouville theory, Crum’s theorem describes the relationship between the original and the associated Hamiltonian systems, which are iso-spectral except for the lowest energy state. Its counterpart in ‘discrete’ quantum mechanics is formulated algebraically, elucidating the basic struc�

Tensor-Optimized Shell Model with Bare Nucleon-Nucleon Interaction for 4He

Abstract: The pion exchange between nucleons generates a strong tensor interaction, which provides a large attractive contribution for the binding energy of nucleus. This noncentral tensor interaction is difficult to handle in the shell model framework, which hinders full understanding of nuclear structure. We develop the tensor-optimized shell model (TOSM) for the strong tensor interaction and now we are able to use bare nucleon-nucleon interaction with the help of the unitary correlation operator method (UCOM) for the short-range hard core. We adopt the nucleon-nucleon interaction, AV8 � , and calculate explicitly the ground state of 4 He and make a detailed comparison with rigorous few-body model calculations. We show a large amount of success of the tensor-optimized shell model with bare nucleon-nucleon interaction for 4 He. Subject Index: 205, 206, 210, 211, 213 It is important to develop a theoretical framework to calculate nuclear structure with many nucleons using the realistic nucleon-nucleon interaction, which is obtained from two nucleon scattering. Recently, it has become possible to calculate nuclei up to a mass of approximately A ∼ 12 1)–3) using the realistic nucleon-nucleon interaction. The method used for the calculation is the Green’s function MonteCarlo method (GFMC) with the use of relative nucleon coordinates. This method introduces various correlation functions with many variational parameters in the nuclear wave function. In GFMC, the nuclear structures and binding energies were successfully reproduced by including three-body interaction. One big surprise is the extremely large contribution of the one pion exchange interaction, which is about 70 ∼ 80% of the entire nucleon-nucleon interaction. In principle, they can extend this method to calculate heavier nuclei. It is, however, extremely time-consuming even with the present computer power. Hence, it is strongly desired to develop a new method of calculating nuclei with large nucleon numbers using the nucleon-nucleon interaction. The nucleon-nucleon interaction has distinctive features, namely there exist

Influence on Observation from IR Divergence during Inflation. II Multi-Field Inflation

Abstract: We propose a way to regularize the fluctuations generated during inflation, whose infrared (IR) corrections diverge logarithmically. In the case of a single-field inflation model, recently, we have proposed a solution to the IR divergence problem. There, we introduced new perturbative variables that better mimic actual observable fluctuations, and proved the regularity of correlation functions with respect to these variables. In this paper, we extend our previous discussions to a multi-field inflation model. We show that, as long as we consider the case that the nonlinear interaction acts for a finite duration, observable fluctuations are also free from IR divergences in the multi-field model. In contrast to the single-field model, to discuss observables, we need to take into account the effects of quantum decoherence, which pick up a unique history of the universe from various possibilities contained in an initial quantum state set naturally in the early stage of the universe. Subject Index: 440, 442

Designing the Dynamics of Globally Coupled Oscillators

Abstract: A method for designing cluster states with prescribed stability is presented for coupled phase oscillator systems with all-to-all coupling. We determine criteria for the coupling function that ensure the existence and stability of a large variety of clustered configurations. We show that such criteria can be satisfied by choosing Fourier coefficients of the coupling function. We demonstrate that using simple trigonometric and localized coupling functions one can realize arbitrary patterns of stable clusters and that the designed systems are capable of performing finite state computation. The design principles may be relevant when engineering complex dynamical behavior of coupled systems, e.g. the emergent dynamics of artificial neural networks, coupled chemical oscillators and robotic swarms. Subject Index: 034, 044, 054, 055

Monopole Operators in N = 4 Chern-Simons Theories and Wrapped M2-Branes

Abstract: Monopole operators in Abelian N = 4 Chern-Simons theories described by circular quiver diagrams are investigated. The magnetic charges of non-diagonal U (1) gauge symmetries form the SU(p) × SU(q) root lattice where p and q are numbers of untwisted and twisted hypermultiplets, respectively. For monopole operators corresponding to the root vectors, we propose a correspondence between the monopole operators and states of a wrapped M2-brane in the dual geometry. Subject Index: 103, 121, 125

Big-Bang Nucleosynthesis Reactions Catalyzed by a Long-Lived Negatively Charged Leptonic Particle

Abstract: An accurate quantum three-body calculation is performed for the new type of big-bang nucleosynthesis (BBN) reactions that are catalyzed by a hypothetical long-lived negatively charged, massive leptonic particle (called X−) such as the supersymmetric (SUSY) particle stau, the scalar partner of the tau lepton. It is known that if the X− particle has a lifetime τX >∼ 10 s, it can capture a light element previously synthesized in standard BBN and form a Coulombic bound state, for example, (7BeX−) at temperature T9 <∼ 0.4 (in units of 10 K), (αX−) at T9 <∼ 0.1 and (pX−) at T9 <∼ 0.01. The bound state, an exotic atom, is expected to induce the following reactions in which X− acts as a catalyst: i) α-transfer reactions such as (αX−)+ d → Li+X, ii) radiative capture reactions such as (7BeX−)+ p → (8BX−)+ γ, iii) three-body breakup reactions such as (7LiX−) + p → α+ α+X−, iv) charge-exchange reactions such as (pX−) + α → (αX−) + p and v) neutron induced reactions such as (8BeX−) + n → Be + X−. In recent papers it has been claimed that some of these X−catalyzed reactions have significantly large cross sections so that the inclusion of the reactions into the BBN network calculation can markedly change the abundances of some elements, giving not only a solution to the Li-Li problem (the calculated underproduction of Li by a factor of ∼ 1000 and overproduction of Li+Be by a factor of ∼ 3) but also a constraint on the lifetime and primordial abundance of the elementary particle X−. However, most of these calculations of the reaction cross sections in the literature were performed assuming too naive models or approximations that are unsuitable for these complicated low-energy nuclear reactions. We use a high-accuracy few-body calculation method developed by the authors and provide precise cross sections and rates of these catalyzed BBN reactions for use in the BBN network calculation.

Clustering of Huygens' Clocks

Abstract: We study synchronization of a number of pendulum clocks hanging from an elastically fixed horizontal beam. It has been shown that after a transient, different types of synchronization between pendulums can be observed; (i) the complete synchronization in which all pendulums behave identically, (ii) pendulums create three or five clusters of synchronized pendulums, (iii) anti-phase synchronization in pairs (for even n). We give evidence why the configurations with a different number of clusters are not observed. Subject Index: 000, 034 In the 17th century the Dutch researcher Christian Huygens showed that a couple of mechanical clocks hanging from a common support were synchronized. 1) Over the last three decades the subject of the synchronization has attracted the increasing attention from different fields. 2)−4) In Huygens experiment 1),5)−9) clocks (subsystems) are coupled thought elastic structure. Generally, this type of coupling allows investigating how the dynamics of the particular subsystem is influenced by the dynamics of other subsystems. 10)−12) However, the precise dynamics of the n clocks hanging from the common support is unknown. Here, we study a synchronization problem for n pendulum clocks hanging from an elastically fixed horizontal beam. Each pendulum performs a periodic motion which starts from different initial conditions. We show that after a transient, different types of synchronization between pendulums can be observed; (i) the complete synchronization in which all pendulums behave identically, (ii) pendulums create three or five clusters of synchronized pendulums, (iii) anti-phase synchronization in pairs (for even n). Our results demonstrate that other stable cluster configurations do not exist. We anticipate our assay to be a starting point for further studies of the synchronization and creation of the small-worlds 13)−16) in the systems coupled by an elastic medium. For example, the behavior of the biological systems (groups of humans or animals) located on elastic structure could be investigated. In particular, a general mechanism for crowd synchrony can be identified. The large oscillations of London’s Millennium Bridge on the day it was opened have restarted the interest in be dynamical behavior of the systems coupled by elastic structure. The detailed theoretical and experimental explanation of the phenomena observed by Huygens for two pendulum clocks has been presented. 5)−9) In our pre

Towards a Theory of Entropy Production in the Little and Big Bang

Abstract: We propose a broadly applicable formalism for the description of coarse grained entropy production in quantum mechanical processes. Our formalism is based on the Husimi transform of the quantum state, which encodes the notion that information about any quantum state is limited by the experimental resolution. We show in two analytically tractable cases (the decay of an unstable vacuum state and reheating after cosmic inflation) that the growth rate of the Wehrl entropy associated with the Husimi function approaches the classi

Vacuum Structure around Identity-Based Solutions

Abstract: We explore the vacuum structure in bosonic open string field theory expanded around an identity-based solution parameterized by a (≥ −1/2). Analyzing the expanded theory using level truncation approximation up to level 14, we find that the theory has a stable vacuum solution for a > −1/2. The vacuum energy and gauge invariant overlap numerically approach those of the tachyon vacuum solution with increasing truncation level. We also find that, at a = −1/2, there exists an unstable vacuum solution in the expanded theory and it rapidly becomes the trivial zero configuration just above a = −1/2. The numerical behavior of the two gauge invariants suggests that the unstable solution corresponds to the perturbative open string vacuum. These results reasonably support the expectation that the identity-based solution is a trivial pure gauge configuration for a > −1/2, but it can be regarded as the tachyon vacuum solution at a = −1/2.

Black Holes in the Dilatonic Einstein-Gauss-Bonnet Theory in Various Dimensions. II Asymptotically AdS Topological Black Holes

Abstract: We study asymptotically AdS topological black hole solutions with k =0 (plane symmetric) in the Einstein gravity with Gauss-Bonnet term, the dilaton and a “cosmological constant” in various dimensions. We derive the field equations for suitable ansatz for general D dimensions. We determine the parameter regions including dilaton couplings where such solutions exist and construct black hole solutions of various masses numerically in D =4 , 5, 6 and 10 dimensional spacetime with (D − 2)-dimensional hypersurface of zero curvature. Subject Index: 121, 122, 454

Instabilities of kerr-AdS5 × S5 spacetime

Abstract: We study gravitational perturbations of the Kerr-AdS_5 x S^5 spacetime with equal angular momenta. In this spacetime, we found the two kinds of classical instabilities, superradiant and Gregory-Laflamme instabilities. The superradiant instability is caused by the wave amplification via superradiance, and by wave reflection due to the potential barrier of the AdS spacetime. The Gregory-Laflamme instability appears in Kaluza-Klein modes of the internal space S^5 and breaks the symmetry SO(6). Taken into account these instabilities, the phase structure of Kerr-AdS_5 x S^5 spacetime is revealed. The implication for the AdS/CFT correspondence is also discussed.

Quarkyonic matter in lattice QCD at strong coupling

Abstract: The QCD phase transition at finite temperature (T ) is the latest vacuum phase transition in our universe, and it can be experimentally investigated at RHIC and LHC. Phase transitions at finite chemical potential (μ) in dense matter may be also realized during black hole formation or in neutron stars, where we have the following central question. “What is the next to the hadronic Nambu-Goldstone phase in the larger μ direction ?” Monte-Carlo (MC) simulations are not yet reliable in the region μ/T > 1 because of the notorious sign problem, then it is necessary to invoke some approximations such as the large number of colors (Nc) or the strong coupling limit (SCL)2)–9) in order to answer this question in QCD. Recently, McLerran and Pisarski have shown that the next phase at large Nc should be the so called quarkyonic phase, in which the colors are confined and the baryon density is high.1) At large Nc, gluon contribution to the pressure ∼ O(N2 c ) is larger than those from hadrons ∼ O(1) and quarks ∼ O(Nc), then the deconfinement transition temperature Td is independent of the quark chemical potential μ as far as it is moderate μ ∼ O(1). In the confined region T mq and soon reaches high density ∼ O(Nc). This dense matter has a characteristic feature that it is made of quarks, while only baryonic excitations are allowed because it is confined. If the quarkyonic phase is the next at Nc = 3, it may be formed at high densities in compact astrophysical phenomena or in heavy-ion collisions at 10-100 A GeV. MC results with the density of state method also show the transition to high density phase,10) but its nature is not yet known. Very recently, quarkyonic matter is found to exist at Nc = 3 in effective models of QCD.12)–14) It is now very important and urgently required to discuss the possibility of the quarkyonic matter phase in QCD for Nc = 3. The above discussion tells us that the quarkyonic transition, the transition from the chiral broken Nambu-Goldstone (NG) phase to the quarkyonic matter, is characterized by the quark number density. If the quarkyonic matter exists, the quarkyonic transition occurs at μ ∼ mq where density rapidly grows as ρq = O(1) → O(Nc), and the chiral restoration follows at higher chemical potential as shown in Fig. 1. In this paper, we discuss the possibility of the quarkyonic matter in the strong coupling lattice QCD (SC-LQCD),2)–8) which is another powerful tool in studying dense mat-

ω-ρ0 Mixing as a Possible Origin of the Hypothetical Isospin Non-Conservation in the X(3872) → π+π−J/ψ Decay

Abstract: The ratio of branching fractions Br(X(3872) → γJ/ψ)/Br(X(3872) → π + π � J/ψ )i s studied by assuming that the X(3872) → π + π � J/ψ decay proceeds through the ρ 0 meson pole which is caused by the ω-ρ 0 mixing. As the result, it is seen that the calculated ratio is compatible with the measured values of the ratio when X(3872) is an axial-vector tetra-quark state, while it would be much larger than the measurements when it is a charmonium. Therefore, the existing data on the ratio seem to favor the tetra-quark interpretation of X(3872) over the charmonium, although a small mixing of the charmonium is not excluded. Subject Index: 169, 232

Adaptive H∞ Anti-Synchronization for Time-Delayed Chaotic Neural Networks

Abstract: In this paper, an adaptive H∞ control scheme is developed to study the antisynchronization behavior of time-delayed chaotic neural networks with unknown parameters. This adaptive H∞ anti-synchronization controller is designed based on LyapunovKrasovskii theory and an analytic expression of the controller with its adaptive laws of parameters is shown. The proposed synchronization method guarantees the asymptotical anti-synchronization of drive and response systems. Furthermore, this method reduces the effect of external disturbance to an H∞ norm constraint. The proposed controller can be obtained by solving a linear matrix inequality (LMI) problem. An illustrative example is given to demonstrate the effectiveness of the proposed method. Subject Index: 044, 055

KEKB B-Factory, The Luminosity Frontier

Abstract: As an introduction, let us begin with a brief introduction of particle colliders related to KEKB. There have been two colliders. The first one was TRISTAN,1) a single ring electron-positron collider with a circumference of 3 km, at the centerof-mass energy up to 64 GeV. TRISTAN was approved in 1981, and experiments started in 1987. Its main object was the discovery of the t-quark, whose mass was not known when it was started. The second collider in Japan is KEKB, a double-ring collider with asymmetric energy 3.5 GeV positrons and 8 GeV electrons, built in the same tunnel as TRISTAN. KEKB was approved in 1994, experiments started in 1999, and then have continued through 2009. KEKB’s energy is tuned around the resonance Υ (4S) ≈ 10.56 GeV to observe the asymmetry in the decay of Band B-mesons. KEKB’s luminosity reached 1.96×1034 cm−2 s−1 in 2009, which is twice as high as its design luminosity. PEP-II2) is also a double-ring collider with 3.1 GeV positrons and 9 GeV electrons built in the same tunnel as PEP, which was a single-ring collider with 2.2 km circumference at SLAC. It was a peculiar situation in the history of colliders in the world that the two machines, KEKB and PEP-II were designed, constructed, and operated at the same time in parallel, with the same scientific goal. This was a severe head-to-head competition. At the beginning PEP-II made a good start in the luminosity, but KEKB has taken a lead since 2001. PEP-II ended its operation in 2008, with the highest luminosity 1.2 × 1034 cm−2 s−1. The competition between the two machines provided various benefits to both. It was not hostile but rather cooperative. Most information was open to each other via meetings, web, and visiting people. Both sides invited reviewers from the other to participate in machine review committees.

New Approach for Evaluating Incomplete and Complete Fusion Cross Sections with Continuum-Discretized Coupled-Channels Method

Abstract: We propose a new method for evaluating incomplete and complete fusion cross sections separately using the Continuum-Discretized Coupled-Channels method. This method is applied to analysis of the deuteron induced reaction on a Li target up to 50 MeV of the deuteron incident energy. Effects of deuteron breakup on this reaction are explicitly taken into account. Results of the method are compared with those of the Glauber model, and the difference between the two is discussed. It is found that the energy dependence of the incomplete fusion cross sections obtained by the present calculation is almost the same as that obtained by the Glauber model, while for the complete fusion cross section, the two models give markedly different energy dependence. We show also that a prescription for evaluating incomplete fusion cross sections proposed in a previous study gives much smaller result than an experimental value.

Black Holes in the Dilatonic Einstein-Gauss-Bonnet Theory in Various Dimensions. III. Asymptotically AdS Black Holes with k = +-1

Abstract: We study black hole solutions in the Einstein-Gauss-Bonnet gravity with the dilaton and a negative “cosmological constant”. We derive the field equations for the static spherically symmetric (k = 1) and hyperbolically symmetric (k = −1) spacetime in general D dimensions. The system has some scaling symmetries which are used in our analysis of the solutions. Nontrivial asymptotically AdS solutions are obtained numerically in D =4 –6 and 10 dimensional spacetimes. For spherically symmetric solutions, there is the minimum horizon radius below which no solution exists in D = 4 – 6. However in D = 10, there is not such lower bound but the solution continues to exist to zero horizon size. For hyperbolically symmetric solution, there is the minimum horizon radius in all dimensions. Our solutions can be used for investigations of the boundary theory through AdS/CFT correspondence. We also discuss the possible fate of these black hole solutions. Subject Index: 121, 122, 454