/pdf/construction-of-a-crossing-symmetric-regge-behaved-amplitude-35hymztfl9.pdf

Construction of a crossing - symmetric, Regge behaved amplitude for linearly rising trajectories

Operator formulation of interacting string field theory (II)

Operator Formulation of Interacting String Field Theory

Since the discovery of the first charmed meson in 1976, many open-charm and open-bottom hadrons were observed. In 2003 two narrow charm-strange states $D_{s0}^*(2317)$ and $D_{s1}(2460)$ were discovered by the BaBar and CLEO Collaborations, respectively. After that, more excited heavy hadrons were reported. In this work, we review the experimental and theoretical progress in this field.

A review of the open charm and open bottom systems

Dual-resonance models

Quantization Conditions for Regge Intercepts and Hadron Masses

We propose a general procedure for constructing the scattering amplitudes of hadrons with external currents. These are obtained from a representation of theN-point function for hadrons and leptons, in the lowest order of the weak constant. We consider a model with external scalar mesons and vector currents only. Current conservation is not required. We study the form factor, electroproduction and Compton scattering finding good analytic properties for the amplitudes.

Nonstrong amplitudes in a veneziano-type model.

The vertex operators associated with the transverse states of DRM are explicitly written. As an application of this result the couplings of three excited «transverse» states are explicitly computed.

/pdf/couplings-of-three-excited-particles-in-the-dual-resonance-9id1uddjxe.pdf

Couplings of three excited particles in the dual-resonance model

In this paper we study the reactions $\ensuremath{\pi}\ensuremath{\pi}\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\omega}({1}^{\ensuremath{-}})$, $\ensuremath{\pi}\ensuremath{\pi}\ensuremath{\rightarrow}\ensuremath{\pi}{A}_{2}({2}^{+})$, and $\ensuremath{\pi}\ensuremath{\pi}\ensuremath{\rightarrow}\ensuremath{\pi}{\ensuremath{\omega}}_{3}({3}^{\ensuremath{-}})$ as a bootstrap system for natural-parity trajectories We start from the solution of our previous work that gave, among other results, expressions for the trajectory and residue functions as well as mass formulas, in agreement with experiment Here we study in detail the sum rules as a function of momentum transfer $t$ We find a set of residue functions $\ensuremath{\beta}(t)$ that are self-consistent and such that the Regge and resonance sides of the equations are almost equal in a large region of $t$ We study also a step-by-step approximation that, at each stage, enlarges the region where the equations are valid We find, however, that the leading Regge trajectories, even if infinitely rising, cannot bootstrap themselves We outline two possible (not incompatible) ways of implementing the bootstrap The first way demands an optimized choice of the cutoff parameter and considers the whole family of reactions $\ensuremath{\pi}\ensuremath{\pi}\ensuremath{\rightarrow}\ensuremath{\pi}{X}_{J}$ (${X}_{J}$ being a normal-parity state of spin $J$) Our results for $J\ensuremath{\le}3$ show that this is a definite possibility The second way is to consider a whole family (parent and daughters) as participating in the bootstrap We find this possibility also attractive, and as a consequence we find that daughters must be parallel to the parent, for linear trajectories The properties of our parametrization are also discussed\char22{}in particular, the Khuri paradox and the coupling of high-spin resonances to the system We also compare our results with experiment whenever possible Our ${A}_{2}$ trajectory, for instance, follows the Gell-Mann mechanism, and the exponential $t$ dependence of our residue functions is perfectly consistent with the one found in recent phenomenological fits to inelastic reactions

Bootstrap of Meson Trajectories from Superconvergence

We study the generalized superconvergent sum rules for a number of processes of the kind $P+P\ensuremath{\rightarrow}P+V$, where $P$ and $V$ stand for pseudoscalar and vector mesons, respectively. We find simple algebraic equations for the parameters of the leading Regge trajectories which are exchanged. The results are in good agreement with experiments. The limit of SU(3) symmetry is also considered.

M. Ademollo

Papers

Quantization Conditions for Regge Intercepts and Hadron Masses

Nonstrong amplitudes in a veneziano-type model.

Couplings of three excited particles in the dual-resonance model

Bootstrap of Meson Trajectories from Superconvergence

Bootstraplike Conditions from Superconvergence