Related papers: Center of mass motion in bag model
Using the CLEO detector at the Cornell Electron Storage Ring, we have studied the distribution of kinematic variables in the decay Lambda_c^+ -> Lambda e^+ nu_e. By performing a four-dimensional maximum likelihood fit, we determine the form…
We report results on the $\pi$-$\gamma$ transition form factor obtained within the hard scattering approach including transverse momentum effects and Sudakov corrections. The results clearly favor distribution amplitudes close to the…
In a covariant quark-diquark model, we investigate the rare decay of $\Lambda_b \rightarrow n l^+ l^-$ and $\Lambda_b \rightarrow n \gamma$ in the Bethe-Salpeter equation approach. In this model the baryons are treated as bound states of a…
Meson Green's functions and decay constants $f_{\Gamma}$ in different channels $\Gamma$ are calculated using the Field Correlator Method. Both, spectrum and $f_\Gamma$, appear to be expressed only through universal constants: the string…
We present a study in the quenched approximation of the $B$ parameter $B_B$ and the decay constant $f_B$ using heavy-quark propagators implemented in the static approximation, and light-quark propagators computed using an $O(a)$-improved…
Two particular ratios related to mesons are proposed for the study of the conformal window in $SU(3)$ gauge theory and fundamental fermions. Lattice and other studies indicate that the lower end, $N_f^*$, is at around 7 - 13 flavors which…
A systematic calculation for the transition form factors of heavy to light mesons ($B,B_s,D,D_s \to \pi, K, \eta, \rho, K^*, \omega, \phi$) is carried out by using light-cone sum rules in the framework of heavy quark effective field theory.…
The masses and decay constants of the light vector mesons $\rho/\omega$, $\phi$ and $K^\star$ are studied within a ladder-rainbow truncation of the coupled Dyson-Schwinger and Bethe-Salpeter equations of QCD with a model 2-point gluon…
Using events in which one of two neutral B mesons from the decay of an Y(4S) meson is fully reconstructed, we determine parameters governing decay (\Delta\Gamma_d/\Gamma_d), CP and T violation (|q/p|), and CP and CPT violation (Rez,Imz).…
Masses and decay constants of mesons containing a single $c$ or $b$ quark are described within the framework of heavy-quark symmetry. The $B_s^* - B_s$ and $\bar B^{*0} - \bar B^0$ mass splittings are found equal to within a fraction of an…
Although well studied, the neutron still offers a unique laboratory for precise tests of Standard Model (SM) predictions. Neutron decay is free of nuclear structure corrections present in nuclear beta decays, and, with a $10^8$ times larger…
Modifications of baryon properties due to the restoration of the chiral symmetry in an external hot and dense baryon medium are investigated in an effective chiral quark-meson theory. The nucleon arises as a soliton of the Gell-Mann -…
It is well known that estimating cosmological parameters from cosmic microwave background (CMB) data alone results in a significant degeneracy between the total neutrino mass and several other cosmological parameters, especially the Hubble…
It is shown that a 25(20)% difference between the decay constants $f_{D_s}(f_{B_s})$ and $f_D(f_B)$ occurs due to large differences in the pole masses of the $s$ and $d(u)$ quarks. The values $\eta_D =f_{D_s}/f_D\approx 1.23(15)$, recently…
We calculate the decay constant of $D_s$ and $D_s^{*}$ with $\bar{B}^0 \ra D^{+}\ell^{-}\nu$ and $\bar{B}^0 \ra D^{+}D_s^{-(*)}$ decays. In our analysis we assume that factorization ansatz works and used two different form factor behaviours…
Recently, a variant of the Bohr Hamiltonian was proposed where the mass term is allowed to depend on the beta variable of nuclear deformation. Analytic solutions of this modified Hamiltonian have been obtained using the Davidson and the…
We study the baryon vertex (BV) in the presence of medium using DBI action and the force balance condition between BV and the probe branes. We note that a stable BV configuration exists only in some of the confining backgrounds. For the…
The influence of dark matter particle decay on the baryon-to-photon ratio has been studied for different cosmological epochs. We consider different parameter values of dark matter particles such as mass, lifetime, the relative fraction of…
We study the decay constants ($f_M$) of the heavy vector ($D^{*}$, $D^{*}_{s}$, $B^{*}$, $B^{*}_{s}$, $B^{*}_{c}$) and tensor ($D_{2}^{*}$, $D_{s2}^{*}$, $B^{*}_{2}$, $B^{*}_{s2}$) mesons in the light front quark model. With the known…
We augment standard branching Brownian motion by adding a competitive interaction between nearby particles. Informally, when particles are in competition, the local resources are insufficient to cover the energetic cost of motion, so the…