Related papers: QCD Constraints on Form Factor Shapes
Baryon form factors can be analyzed in a largely model-independent fashion in terms of two complementary approaches. These are chiral perturbation theory and dispersion relations. I review the status of dispersive calculations of the…
The electromagnetic form factors of hadrons at large momentum transfer have been the subject of intense theoretical and experimental scrutiny over the past two decades, yet there is still not a universally-accepted framework for their…
The form factors of the light pseudoscalar mesons are investigated in a dispersive formalism based on hadronic unitarity, analyticity and the OPE expansion of the QCD Green functions. We propose generalizations of the original mathematical…
We present a method for parametrizing heavy meson semileptonic form factors using dispersion relations, and from it produce a two-parameter description of the B -> B elastic form factor. We use heavy quark symmetry to relate this function…
I discuss recent applications of QCD light-cone sum rules to various form factors of pseudoscalar mesons. In this approach both soft and hard contributions to the form factors are taken into account. Combining QCD calculation with the…
We present a method for parametrizing heavy meson semileptonic form factors using dispersion relations, and from it produce a two-parameter description of the B -> B elastic form factor. We use heavy quark symmetry to relate this function…
The dispersive approach to quantum chromodynamics is applied to the study of the hadronic vacuum polarization function and associated quantities. This approach merges the intrinsically nonperturbative constraints, which originate in the…
Understanding the effects of a background hadronic medium on hadronic observables is important in the context of hadron structure. Many experiments probing nucleon structure make use of nuclear targets and unraveling the modifications that…
It is generally assumed that due to factorization of long- and short-distance dynamics perturbative QCD can be applied to exclusive hadronic reactions at large momentum transfers. Within such a perturbative approach diquarks turn out to be…
We use chiral perturbation theory to study the extrapolations necessary to make physical predictions from lattice QCD data for the electromagnetic form factors of pseudoscalar mesons. We focus on the quark mass, momentum, lattice spacing,…
I briefly discuss the derivation of dispersive sum rules constraining semileptonic form-factors. I outline the use of these constraints in the context of charmless semileptonic decays and suggest how, in combination with other theoretical…
We review the present situation with hadron form factors in space-like and time-like regions. The possibility to transfer high momenta, and therefore to access small internal nucleon distances, allows to test nucleon models in particular…
We analyze the isovector vector form factors of $D$, $D^*$, $B$, and $B^*$ mesons at low energies. We employ all constraints due to chiral and heavy-quark symmetry, and include the physics of resonant pion-pion rescattering in a…
The quark parts of the gravitational form factors of hyperons are calculated by means of the light-cone QCD sum rule. In the calculations, the distribution amplitudes (DAs) of $\Sigma$, $\Xi$ and $\Lambda$ together with the general forms of…
We use dispersive techniques to address the behavior of the pion form factor as $Q^2 \to \infty$ and $Q^2 \to 0$. We perform the matching with the constraints of perturbative QCD and chiral perturbation theory in the high energy and low…
Dispersion relations for the scattering of hadrons are considered within the framework of Quantum Chromodynamics. It is argued that the original methods of proof remain applicable. The setting and the spectral conditions are provided by an…
The method of QCD sum rules has proven to be particularly useful in heavy quark physics, where a small distance scale is provided by the inverse heavy quark mass. We present two new examples for the application of this method to B-physics:…
We demonstrate that fermion masses in the Standard Model (SM) can be constrained by the dispersion relations obeyed by hadronic and semileptonic decay widths of a fictitious heavy quark $Q$ with an arbitrary mass. These relations, imposing…
A method of deriving bounds on the weak meson form factors, based on perturbative QCD, analyticity and unitarity, is generalized in order to fully exploit heavy quark spin symmetry in the ground state $(L=0)$ doublet of pseudoscalar $(B)$…
We review theoretical approaches to form factors that arise in heavy-meson decays and are hadronic expressions of non-perturbative QCD. After motivating their origin in QCD factorisation, we retrace their evolution from quark-model…