119335036
Exclusive semileptonic and nonleptonic decays of the B c meson
We study exclusive nonleptonic and semileptonic decays of the B{sub c}-meson within a relativistic constituent quark model previously developed by us. For the nonleptonic decays we use the factorizing approximation. We update our model parameters by using new experimental data for the mass and the lifetime of the B{sub c} meson and the leptonic decay constants of the D-meson. We calculate the branching ratios for a large set of exclusive nonleptonic and semileptonic decays of the B{sub c} meson and compare our results with the results of other studies. As a guide for further experimental exploration we provide explicit formulas for the full angular decay distributions in the cascade decays B{sub c}{sup -}{yields}J/{psi}({yields}l{sup +}l{sup -})+{rho}{sup -}({yields}{pi}{sup -}{pi}{sup 0}) and B{sub c}{sup -}{yields}J/{psi}({yields}l{sup +}l{sup -})+W{sub off-shell}{sup -}({yields}l{sup -}+{nu}{sub l})
119064723
The Quark Confinement Model of Hadrons
INTRODUCTION QCD-HADRONIZATION QCD functional with a gluon background Quarks in vacuum gluon fields QCD bosonization The composites condition Z^O2 = 0 THE QUARK CONFINEMENT MODEL Quark-hadron interactions The calculation technique in the QCM The choice of the confinement function The chiral fit LIGHT MESONS Introduction The interaction Lagrangian The Dalitz decays The pion form factor Scalar mesons A role of axial mesons in the electroweak decay ^D*p->^DIevyPion and kaon polarizabilities Appendix References BARYONS AS THREE-QUARK SYSTEMS Introduction Quark currents of baryons Confinement ansatz for three-quark states Quark-diquark approximation Electromagnetic form factors of baryons Strong meson-baryon form factors HEAVY QUARKS Introduction ... Toward heavy quarks Kinematics of semileptonic meson decays Heavy final states Light final states b-c flavor changing decays of baryons Appendix References INDEX
995629
The Semileptonic decays of the $B_c$ meson
We study the semileptonic transitionsBc → �c, J/ , D, D ∗ , B, B ∗ , Bs, B ∗ s in the framework of a relativistic constituent quark model. We use experimental data on leptonic J/ decay, lattice and QCD sum rule results on leptonic Bc decay, and experimental data on radiativec transitions to adjust the quark model parameters. We compute all form factors of the above semileptonic Bc-transitions and give predictions for various semileptonic Bc decay modes including their �-modes when they are kinematically accessible. The impli- cations of heavy quark symmetry for the semileptonic decays are discussed and are shown to be manifest in our explicit relativistic quark model calcu- lation. A comparison of our results with the results of other calculations is performed.
18648204
Decay Constants and Semileptonic Form Factors of Pseudoscalar Mesons 1
AbstractA relativistic constituent quark model is adopted to give an uniﬁed description of the leptonic andsemileptonic decays of pseudoscalar mesons (π, K, D, D s , B, B s ). The calculated leptonic decayconstants and form factors are found to be in good agreement with available experimental data andthe results of other approaches. Eventually, the model is found to reproduce the scaling behavioursof spin-ﬂavor symmetry in the heavy-quark limit. 1 Introduction Semileptonic decays of pseudoscalar mesons allow to evaluate the elements of the Cabibbo–Kobayashi–Maskawa (CKM) matrix, which are fundamental parameters of the Standard Model. The decay K → πeνprovides the most accurate determination of V us , the semileptonic decays of D and B mesons, D →K(K ∗ )lν, B → D(D ∗ )lν and B → π(ρ)lν, can be used to determine |V cs |, |V cb | and |V ub |, respectively.This program can be performed if the non-perturbative QCD eﬀects, which are parameterized by theform factors, are known. Up to now, these form factors cannot be evaluated from ﬁrst principles, thusmodels, more or less connected with QCD, are usually considered for this purpose. Here we discuss arelativistic quark model [1], previously used to study the baryon form factors [2].This model is based on an eﬀective Lagrangiandescribingthe coupling ofmesons with their constituentquarks. The physical processes are described by the one-loop quark diagrams and meson-quark verticesrelated to the Bethe-Salpeter amplitudes. In principle, the vertex functions and quark propagatorsshouldbe given by the Bethe-Salpeter and Dyson-Schwinger equations, respectively. This kind of analysis isprovided by the Dyson-Schwinger Equation (DSE) studies [3] and an uniﬁed description of light andheavy meson observables was carried out in [4, 5]. Here, instead, we use free propagators for constituentquarks and consider a Gaussian vertex function as Bethe-Salpeter conﬁning function. The adjustableparameters, the widths of Bethe-Salpeter amplitudes in momentum space, and the constituent quarkmasses, are determined from the best ﬁt of available experimental data and some lattice simulations.Our results are in good agreement with experimental data and other approaches. We also reproduce thespin-ﬂavor symmetry relations and scaling for leptonic decay constants and semileptonic form factors inthe heavy-quark limit [6].An approach similar to the one presented here, can be found in [7]. That model is based on meson-quark interactions, so the mesonic transition amplitudes are described by diagrams with heavy mesonsattached to quark loops. The free propagator has been used for light quarks, while the quark propagatorobtained in the heavy-quark limit has been adopted for heavy quarks.
120222175
Isgur-Wise function and observables of lambda(b) baryon
In connection with planned experiments devoted to investigation of semileptonic decays of beauty baryons Isgur-Wise function and observables of $\Lambda_b$ baryon (decay rates and distributions, leptonic spectra and asymmetry parameters) are calculated in the framework of diquark model with taking into account of infrared regime for heavy quark.
198488906
The Box anomaly and radiative decays of eta(eta-prime) mesons
We report on a confined quark model calculation of the transition form factors for the radiative decays of \eta(\eta')->\gamma l^+l^- and \eta(\eta')->\gamma\pi^+\pi^-. The \eta-\eta' mixing angle \theta_P is determined from the set of data on the electromagnetic \eta(\eta') decays. It is found that \theta_P\sim -16.5. The analysis of the dipionic mass distribution in the decay \eta'->\gamma\pi^+\pi^- confirms the existence of a non-resonant contribution which is the box anomaly.
119020799
Another possible interpretation of SN 1a data - without kinematics: Comments on the paper astro-ph/0402512 by A. Riess et al
It is shown here that for redshifts $z < 0.5$ the luminosity distance, which is predicted in author's model astro-ph/0005084 v2, fits well supernova observational data of astro-ph/0402512 by A.Riess et al. Discrepancies for higher $z$ would be explained in the model as a result of specific deformation of SN spectra due to a discrete character of photon energy losses. The model does not require any dark energy; it is based on the conjecture that gravitons are super-strong interacting particles fulfilling a flat non-expanding universe.
1458405
Low-energy quantum gravity: new challenges for an experiment and observation
Some new challenges for an experiment and observation, which are consequences of the model of low-energy quantum gravity by the author, are considered here. In particular, the property of asymptotic freedom of this model leads to the unexpected consequence: if a black hole arises due to a collapse of a matter with some characteristic mass of particles, its full mass should be restricted from the bottom. For usual baryonic matter, this limit of mass is of the order $10^{7}M_{\odot}$.
14365154
Lorentz symmetry violation due to interactions of photons with the graviton background
The average time delay of photons due to multiple interactions with gravitons of the background is computed in a frame of the model of low-energy quantum gravity by the author. The two variants of evaluation of the lifetime of a virtual photon are considered: 1$)$ on a basis of the uncertainties relation (it is a common place in physics of particles) and 2$)$ using a conjecture about constancy of the proper lifetime of a virtual photon. It is shown that in the first case Lorentz violation is negligible: the ratio of the average time delay of photons to their propagation time is equal approximately to $10^{-28}$; in the second one (with a new free parameter of the model), the time-lag is proportional to the difference $\sqrt{E_{01}}-\sqrt{E_{02}}$, where $E_{01}, E_{02}$ are initial energies of photons, and more energetic photons should arrive later, also as in the first case. The effect of graviton pairing is taken into account, too.
12841244
Hubble diagrams of soft and hard radiation sources in the graviton background: to an apparent contradiction between supernova 1a and gamma-ray burst observations
In the sea of super-strong interacting gravitons, non-forehead collisions with gravitons deflect photons, and this deflection may differ for soft and hard radiations. As a result, the Hubble diagram would not be a universal function and it will have a different view for such sources as supernovae in visible light and gamma-ray bursts. Observations of these two kinds are compared here with the limit cases of the Hubble diagram.
18218791
Non-Dopplerian cosmological redshift parameters in a model of graviton-dusty universe
Possible effects, which could be caused by a hypothetical super-strong interaction of photons or massive bodies with single gravitons of the graviton background, are considered. If full cosmological redshift magnitudes are caused by the interaction, then the luminosity distance in a flat non-expanding universe as a function of redshift is very similar to the specific function which fits supernova cosmology data by Riess et al (1998 Astron. J. 116 1009). From another side, in this case every massive body, moving slowly relative to the background, would experience a constant acceleration, proportional to the Hubble constant, of the same order as a small additional acceleration of Pioneer 10, 11.