Related papers: Violations of Dashen's Theorem
By including the strong isospin symmetry breaking effects and the electromagnetic contributions between the pseudoscalar mesons, we calculate the phase shifts of the $P$-wave $\pi\pi$ and $K\pi$ scattering up to $\mathcal{O}(p^4)$ in the…
The $K\to\pi\pi$ system is analyzed in the chiral limit within the Standard Model. We discuss how to connect the short-distance running in the $|\Delta S|=1$ case to the matrix-elements calculated in a low-energy approximation in a…
We calculate the charm-quark contribution to the decay K_L -> mu^+ mu^- in next-to-next-to-leading order of QCD. This new contribution reduces the theoretical uncertainty in the relevant parameter P_c from +/-22% down to +/-7%,…
We generalize the Cottingham formula at finite (T\neq 0) temperature by using the imaginary time formalism. The Cottingham formula gives the theoretical framework to compute the electromagnetic mass differences of the hadrons using a…
In the low energy domain, Chiral Perturbation Theory parametrizes the small chiral symmetry breaking effects, produced by the quark masses $m_u$, $m_d$ and $m_s$, in terms of order parameters of massless QCD. The latter can then, in…
The $SU(3)$ and hyperfine mass splittings of mesons containing a single heavy quark are computed to one-loop order in chiral perturbation theory with heavy quark spin symmetry. Electromagnetic contributions of order $\alpha_em$ are…
The bosonic contributions to the photon mass are shown to be of the same form as the fermionic contributions, but of opposite sign. A mass sum rule for bosons and fermions follows from gauge invariance. Assuming completeness of the standard…
The complete list of electroweak chiral Lagrangian for W', Z' and a neutral light higgs with symmetry $SU(2)_1\otimes SU(2)_2\otimes U(1)$ is provided. The bosonic part is accurate up to order of $p^4$, the matter part involving various…
It has been previously shown that a particular nonperturbative constituent-quark model of hadrons describes experimental measurements of electromagnetic form factors of light charged mesons through a small number of common phenomenological…
The strange-quark vector current form factors of the nucleon are analyzed within the framework of dispersion relations. Particular attention is paid to contributions made by $K\bar{K}$ intermediate states to the form factor spectral…
I demonstrate that the short distance contribution to K --> Pi Pi decays must be supplemented with large distance effects. A hybrid calculation is outlined based on QCD diagrams supplemented by chiral contributions and Pi-Pi phaseshifts.
In this work, the mass of the strange quark is calculated from QCD sum rules for the divergence of the strangeness-changing vector current. The phenomenological scalar spectral function which enters the sum rule is determined from our…
The LHCb measurements on the B ->$ K^*$$\mu^+ \mu^-$ angular observables have shown slight deviations from their Standard Model predictions. The significance of the deviations in the B -> $K^*$$\mu^+ \mu^-$ decay depends on the assumptions…
Observing the mass shifts of mesons immersed in nuclear matter is interesting, as the changes are expected to shed light on the effects of chiral symmetry breaking on the origin of hadron masses. At the same time, it is important to…
We describe two recent theoretical calculations of the $B \to K^* \gamma$ decay. The first method is based on an effective lagrangian incorporating chiral symmetry for the light degrees of freedom and the heavy quark spin-flavor symmetries…
In the present work we study the effects of an unparticle $\unpart$ as the possible source of missing energy in the decay $B \to K (K^*) + {\rm missing energy}$. We find that the dependence of the differential branching ratio on the…
A brief overview of the recent measurements of the branching ratio of the rare $K_L^0 \to \mu^+ \mu^-$ decay in the context of their agreement with the Standard Model (SM) is given. It is shown that KEK result well correlates with the SM…
The relation between the on-shell quark mass and the mass defined in the modified minimal subtraction scheme is computed up to order \alpha_s^3. Implications for the numerical values of the top and bottom quark masses are discussed. We show…
The infinite mass effective theory, when a heavy quark mass tends to infinity, and Chiral perturbation theory at the quark level, based on the extended Nambu -- Jona -- Lasinio model with linear realization of chiral $U(3)\times U(3)$…
Quantum mechanics with quaternionic mass is considered. The momentum eigen-value equation with quaternionic mass yields the Klein-Gordon equation with a mass consisting of longitudinal and traverse masses. The scalar field total mass is…