More about on the short distance contribution to the "B_c -> B_u^* gamma" decay

We calculate the transition form factor for the 'B_c -> B_u^* gamma' decay taking into account only the short distance contribution, in framework of QCD sum rules method. We observe that the transition form factor predicted by the QCD sum rules method is approximately two times larger compared to the result predicted by the Isgur, Scora, Grinstein and Wise model.Comment: 12 pages, 2 figures, LaTeX formatte

Simplified diagrammatic expansion for effective operator

For a quantum many-body problem, effective Hamiltonians that give exact eigenvalues in reduced model space usually have different expressions, diagrams and evaluation rules from effective transition operators that give exact transition matrix elements between effective eigenvectors in reduced model space. By modifying these diagrams slightly and considering the linked diagrams for all the terms of the same order, we find that the evaluation rules can be made the same for both effective Hamiltonian and effective transition operator diagrams, and in many cases it is possible to combine many diagrams into one modified diagram. We give the rules to evaluate these modified diagrams and show their validity.Comment: 5 journal pages, 4 figure

Coupling any number of balls in the infinite-bin model

The infinite-bin model, introduced by Foss and Konstantopoulos, describes the Markovian evolution of configurations of balls placed inside bins, obeying certain transition rules. We prove that we can couple the behaviour of any finite number of balls, provided at least two different transition rules are allowed. This coupling makes it possible to define the regeneration events needed by Foss and Zachary to prove convergence results for the distribution of the balls.Comment: 12 pages, 2 figure

Light-Cone Sum Rules for the Form Factors of the NγΔN\gamma\Delta transition at Q^2=0

The radiative $\Delta \to \gamma N$ transition is examined at the real photon point $Q^2=0$ using the framework of light-cone QCD sum rules. In particular, we determine the sum rules for the transition form factors $G_M(0)$ and $R_{EM}$ up to twist 4.Comment: Talk given at the Workshop on Exclusive Reactions at High Momentum Transfer 200

Magnetooptical sum rules close to the Mott transition

We derive new sum rules for the real and imaginary parts of the frequency-dependent Hall constant and Hall conductivity. As an example, we discuss their relevance to the doped Mott insulator that we describe within the dynamical mean-field theory of strongly correlated electron systems.Comment: 4 pages, 4 ps figures; accepted for publication in PR

"Taylored rules". Does one fit (or hide) all?

Modern monetary policymakers consider a huge amount of information to evaluate events and contingencies. Yet most research on monetary policy relies on simple instrument rules and one relevant underpinning for this choice is the good empirical fit of the Taylor rule. This paper challenges the solidness of this foundation. We investigate the way the coefficients of the Taylor-type rules change over time according to the evolution of general economic conditions. We model the Federal Reserve reaction function during the Greenspan’s tenure as a Logistic Smoothing Transition Regime model in which a series of economic meaningful transition variables drive the transition across monetary regimes. We argue that estimated linear rules are weighted averages of the actual rules working in the diverse monetary regimes, where the weights merely reflect the length and not necessarily the relevance of the regimes. Accordingly, an estimated linear Taylor-type reaction function tends to resemble the rule adopted in the longest regime. Thus, the actual presence of finer monetary policy regimes corrupts the general predictive and descriptive power of linear Taylor-type rules. These latter, by hiding the specific rules at work in the various finer regimes, lose utility directly with the uncertainty in the economy.Instrument Rules, LSTR, Monetary Policy Regime, Risk Management, Taylor Rule

Land Use Dynamics: a Cellular Automata

Usually applications of urban growth cellular automata are related to an only one town, with transition rules and constraints a priori defined. This seems to be a severe limits in applications. The paper presented is born to follow a different kind of approach, so to have rules and constraints directly from observed past data. We consider ten European towns and for each one we have data for time series approx. 40 years long. We deduce rules and constraints directly from the data set, solving an inverse problem (in which we have input and output measures and we have to determine a system model).The study aims to define in detail the stochastic or deterministic character of transition rules (in the stochastic case evaluating transition probability). At last the rules are applied to towns maps (by means of ad hoc cellular automaton). With this cellular automaton we try to simulate past dynamics (for a validation of the model) and also to forecast the spatial development of the towns by means of scenarios (based on the past histories of the cities).

Pseudorandom number generation with self programmable cellular automata

In this paper, we propose a new class of cellular automata – self programming cellular automata (SPCA) with specific application to pseudorandom number generation. By changing a cell's state transition rules in relation to factors such as its neighboring cell's states, behavioral complexity can be increased and utilized. Interplay between the state transition neighborhood and rule selection neighborhood leads to a new composite neighborhood and state transition rule that is the linear combination of two different mappings with different temporal dependencies. It is proved that when the transitional matrices for both the state transition and rule selection neighborhood are non-singular, SPCA will not exhibit non-group behavior. Good performance can be obtained using simple neighborhoods with certain CA length, transition rules etc. Certain configurations of SPCA pass all DIEHARD and ENT tests with an implementation cost lower than current reported work. Output sampling methods are also suggested to improve output efficiency by sampling the outputs of the new rule selection neighborhoods

Sum rules for baryon decuplet magnetic moments

In chiral models with SU(3) group structure, baryon decuplet and octet magnetic moments are evaluated by constructing their sum rules to yield theoretical predictions. In these sum rules we exploit six experimentally known baryon magnetic moments. Sum rules for flavor components and strange form factors of the octet and decuplet magnetic moments and decuplet-to-octet transition magnetic moments are also investigated.Comment: 12 page