N.K. Pak

Gauged Goldstone Boson Effective Action From Direct Integration of Bardeen Anomaly

We derive the effective action which describes the anomalous Goldstone boson interactions in the presence of external flavour SU(N)L×SU(N)R gauge fields, by a direct integration of the Bardeen anomaly. Through comparison with other results, we are able to elucidate the relationship between anomalies based on different regularization schemes. We also give a compact representation of the anomalous part of the fermionic determinant allowing for a simpler rederivation of our results.

Vector mesons within the effective Lagrangian approach

Abstract We construct an effective lagrangian which describes the non-anomalous and the anomalous interactions between the low-lying pseudoscalar mesons and their vector and axial vector partners. By first observing that the approximate non-abelian gauging of the Wess-Zumino-Witten action does not reproduce the purely pionic and electromagnetic low-energy theorems through the vector-meson dominance, we develop a systematic functional subtraction formalism to implement the vector meson dominance unambiguously. This enables us to construct the unique effective π V and π VA actions which reproduce all the low-energy theorems exactly without any constraints on the fundamental parameters of the model.

Meson-gluonium mixing from QCD sum rules☆

Abstract We evaluate the off-diagonal two-point correlation function responsible for the gluonium-meson mixing, including the leading non-perturbative lowest dimension vacuum condensate contributions. Then, using spectral function sum rules approach, we deduce a small meson-gluonium mixing angle. We also derive upper bounds for the η′ and for the strange quark masses.

Exact path integral solution of a class of potentials related to the rigid rotator

Abstract The path integral for the Scarf, Poschl-Teller, and Rosen-Morse potential problems are exactly calculated by connecting them to the rigid rotator problem through suitably chosen point canonical transformations.

Construction of the Effective Vertices and the Gauge Invariant Currents in the Gauged {Wess-Zumino} Action

Abstract The vector flavour current is derived directly from the recently proposed gauged Wess-Zumino action. This gauge covariant expression is used to compute the baryonic and electromagnetic currents. We perform a small field expansion of the pure vector Wess-Zumino action and present the first few terms in a gauge invariant form. Special attention is paid to the two flavour action; in the electromagnetic and the vector-axial vector cases, the results are presented in a manifestly gauge invariant form in terms of the physical pion field.

Rare radiative B→τ+τ−γ decay

Abstract The radiative B → τ + τ − γ decay is investigated in the framework of the Standard Model. When only short (short and long together) distance contributions are taken into account, the Branching Ratio is found as 9.54×10 −9 (1.52×10 −8 ), for the value of the cut δ =0.01 imposed on the photon energy.The radiative B -> tau^+ tau^- gamma decay is investigated in the framework of the Standard Model. When only short (short and long together) distance contributions are taken into account, the Branching Ratio is found as 9.54x10^(-9) (1.52x10^(-8)), for the value of the cut delta = 0.01 imposed on the photon energy.

The Quantization of the Gursey Model

Abstract The Gursey model, a conformally invariant pure spinor model in four dimensions, is quantized to result in an asymptotically free theory.

Radiative B*-->B gamma and D*-->D gamma decays in light-cone QCD sum rules.

The radiative decays

Dipole coefficients in B→Xsγ in supersymmetry with large tanβ and explicit CP violation

B^{*} (D^{*})\to B(D) \gamma

One-loop effects in supergravity models with an additional U(1)

are investigated in the framework of light cone QCD sum rules. The transition amplitude and decay rates are estimated.It is shown that our results on branching ratios of D meson decays are in good agreement with the existing experimental data.