7,657 research outputs found
Comment on `Glueball spectrum from a potential model'
In a recent article, W.-S. Hou and G.-G. Wong [Phys. Rev. D {\bf 67}, 034003
(2003)] have investigated the spectrum of two-gluon glueballs below 3 GeV in a
potential model with a dynamical gluon mass. We point out that, among the 18
states calculated by the authors, only three are physical. The other states
either are spurious or possess a finite mass only due to an arbitrary
restriction of the variational parameter.Comment: Comment on pape
Scattering solutions of the spinless Salpeter equation
A method to compute the scattering solutions of a spinless Salpeter equation
(or a Schrodinger equation) with a central interaction is presented. This
method relies on the 3-dimensional Fourier grid Hamiltonian method used to
compute bound states. It requires only the evaluation of the potential at
equally spaced grid points and yields the radial part of the scattering
solution at the same grid points. It can be easily extended to the case of
coupled channel equations and to the case of non-local interactions.Comment: 7 page
Why Do REITs Repurchase Stock? Extricating the Effect of Managerial Signaling in Open Market Share Repurchase Announcements
This paper explores the effect of stock repurchase announcements on equity returns for publicly traded real estate investment trusts (REITs). In addition to providing analysis of the corporate decision to repurchase shares, the study of share repurchases in the context of REITs provides a novel opportunity to disentangle the impact of competing theories for the abnormal returns observed around repurchase announcements. Prior literature advances six hypotheses to explain the stock price reaction associated with repurchases. Given that the theories all predict the same stock price reaction, existing studies are unable to disentangle the competing hypotheses. The intent of this research is to extricate the signaling hypothesis from the competing explanations to determine whether the managerial signaling hypothesis is a credible explanation for the abnormal returns observed around share repurchase announcements. After controlling for relevant economic variables, we provide evidence for the efficacy of the managerial signaling hypothesis.
A semiclassical model of light mesons
The dominantly orbital state description is applied to the study of light
mesons. The effective Hamiltonian is characterized by a relativistic kinematics
supplemented by the usual funnel potential with a mixed scalar and vector
confinement. The influence of two different finite quark masses and potential
parameters on Regge and vibrational trajectories is discussed.Comment: 1 figur
Electromagnetic splitting for mesons and baryons using dressed constituent quarks
Electromagnetic splittings for mesons and baryons are calculated in a
formalism where the constituent quarks are considered as dressed
quasiparticles. The electromagnetic interaction, which contains coulomb,
contact, and hyperfine terms, is folded with the quark electrical density. Two
different types of strong potentials are considered. Numerical treatment is
done very carefully and several approximations are discussed in detail. Our
model contains only one free parameter and the agreement with experimental data
is reasonable although it seems very difficult to obtain a perfect description
in any case.Comment: 14 pages, Revised published versio
On the modification of Hamiltonians' spectrum in gravitational quantum mechanics
Different candidates of Quantum Gravity such as String Theory, Doubly Special
Relativity, Loop Quantum Gravity and black hole physics all predict the
existence of a minimum observable length or a maximum observable momentum which
modifies the Heisenberg uncertainty principle. This modified version is usually
called the Generalized (Gravitational) Uncertainty Principle (GUP) and changes
all Hamiltonians in quantum mechanics. In this Letter, we use a recently
proposed GUP which is consistent with String Theory, Doubly Special Relativity
and black hole physics and predicts both a minimum measurable length and a
maximum measurable momentum. This form of GUP results in two additional terms
in any quantum mechanical Hamiltonian, proportional to and
, respectively, where is the GUP
parameter. By considering both terms as perturbations, we study two quantum
mechanical systems in the framework of the proposed GUP: a particle in a box
and a simple harmonic oscillator. We demonstrate that, for the general
polynomial potentials, the corrections to the highly excited eigenenergies are
proportional to their square values. We show that this result is exact for the
case of a particle in a box.Comment: 11 pages, to appear in Europhysics Letter
Universality of Regge and vibrational trajectories in a semiclassical model
The orbital and radial excitations of light-light mesons are studied in the
framework of the dominantly orbital state description. The equation of motion
is characterized by a relativistic kinematics supplemented by the usual funnel
potential with a mixed scalar and vector confinement. The influence of finite
quark masses and potential parameters on Regge and vibrational trajectories is
discussed. The case of heavy-light mesons is also presented.Comment: 12 page
REIT Stock Repurchases: Completion Rates, Long - Run Returns, and the Straddle Hypothesis
This study of real estate investment trusts (REITs) analyzes three possible explanations for the stock price reaction to a repurchase announcement and the subsequent repurchase behavior of managers under each hypothesis. Two of the hypotheses, the signaling hypothesis and the exchange option hypothesis, are established in the existing literature; the third hypothesis is a modification of the exchange option hypothesis. The exchange option hypothesis is extended to allow for additional flexibility in management decisions. This extended exchange option hypothesis is termed the ââstraddleââ hypothesis because it provides management with both a call and put option. The empirical analyses show the straddle hypothesis is a more robust explanation of changes in shares outstanding in the postannouncement period than the alternative explanations.
A Note on Internet Resources for the Entrepreneur: A Small Firm Finance Perspective
This article concentrates on internet resources that are available to those interested in entrepreneurial and small firm finance. Specifically, I present web pages that focus on general entrepreneurial issues and different avenues for acquiring capital. The three main areas of external financing that I include are venture capital, going public, and loans. Additionally, the advantages of using electronic mail, distribution lists, and personal web page applications are discussed and several examples presented
Center Domains and their Phenomenological Consequences
We argue that the domain structure of deconfined QCD matter, which can be
inferred from the properties of the Polyakov loop, can simultaneously explain
the two most prominent experimentally verified features of the quark-gluon
plasma, namely its large opacity as well as its near ideal fluid properties
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