Decay Constants Of Heavy-light Mesons Research Articles

Spin averaged mass spectra and decay constants of heavy quarkonia and heavy-light mesons using bi-confluent heun equation

Spin averaged mass spectra and decay constants of heavy quarkonia and heavy-light mesons using bi-confluent heun equation

Nonrelativistic quark model for mass spectra and decay constants of heavy-light mesons using conformable fractional derivative and asymptotic iteration method

In this paper, we use the concept of conformable fractional derivative to study the nonrelativistic radial Schrödinger equation. We suggest an extended version of the Cornell potential as the quark–antiquark interaction of light and heavy mesons. We generalize the asymptotic iteration method to the fractional domain. The latter is used to calculate the energy eigenvalues, as well as the effect of the fractional order [Formula: see text] on energy spectra. To test the applicability of our model, we use the obtained results to reproduce the mass spectra of some light and heavy mesons such as [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] quarks. The mass spectra are obtained at different values of the fractional order parameter [Formula: see text] and were compared with experimental results and other relevant theoretical works. Using the wave function, we calculated the decay constants for heavy-light [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] mesons. Our results are found to be in good agreement with the experimental data, and improved in comparison with other theoretical previsions.

Masses, decay constants and HQE matrix elements of pseudoscalar and vector heavy-light mesons in LQCD

We present a precise lattice computation of masses and decay constants of pseudoscalar and vector heavy-light mesons with mℓ = mu/d, ms and mh in the range (mc, ∼ 3mc). We employ the ETMC gauge configurations with both Nf = 2 and Nf = 2 + 1 + 1 dynamical quarks and the ETMC ratio method to reach the b-quark mass. In the case of the vector decay constants an unusual quenching effect of the strange quark is observed. Specific masses combinations are then analyzed in terms of the Heavy Quark Expansion (HQE) to extract matrix elements up to dimension-6, including , and and with a good precision. These parameters play a crucial role in the inclusive determination of the Vub and Vcb matrix elements.

B - and D -meson leptonic decay constants from four-flavor lattice QCD

We calculate the leptonic decay constants of heavy-light pseudoscalar mesons with charm and bottom quarks in lattice quantum chromodynamics on four-flavor QCD gauge-field configurations with dynamical $u$, $d$, $s$, and $c$ quarks. We analyze over twenty isospin-symmetric ensembles with six lattice spacings down to $a\approx 0.03$~fm and several values of the light-quark mass down to the physical value $\frac{1}{2}(m_u+m_d)$. We employ the highly-improved staggered-quark (HISQ) action for the sea and valence quarks; on the finest lattice spacings, discretization errors are sufficiently small that we can calculate the $B$-meson decay constants with the HISQ action for the first time directly at the physical $b$-quark mass. We obtain the most precise determinations to-date of the $D$- and $B$-meson decay constants and their ratios, $f_{D^+} = 212.7(0.6)$~MeV, $f_{D_s} = 249.9(0.4)$~MeV, $f_{D_s}/f_{D^+} = 1.1749(16)$, $f_{B^+} = 189.4 (1.4)$~MeV, $f_{B_s} = 230.7(1.3)$~MeV, $f_{B_s}/f_{B^+} = 1.2180(47)$, where the errors include statistical and all systematic uncertainties. Our results for the $B$-meson decay constants are three times more precise than the previous best lattice-QCD calculations, and bring the QCD errors in the Standard-Model predictions for the rare leptonic decays $\overline{\mathcal{B}}(B_s \to \mu^+\mu^-) = 3.64(11) \times 10^{-9}$, $\overline{\mathcal{B}}(B^0 \to \mu^+\mu^-) = 1.00(3) \times 10^{-10}$, and $\overline{\mathcal{B}}(B^0 \to \mu^+\mu^-)/\overline{\mathcal{B}}(B_s \to \mu^+\mu^-) = 0.0273(9)$ to well below other sources of uncertainty. As a byproduct of our analysis, we also update our previously published results for the light-quark-mass ratios and the scale-setting quantities $f_{p4s}$, $M_{p4s}$, and $R_{p4s}$. We obtain the most precise lattice-QCD determination to date of the ratio $f_{K^+}/f_{\pi^+} = 1.1950(^{+16}_{-23})$~MeV.

Mass Spectra and Decay Constants of Heavy-Light Mesons: A Case Study of QCD Sum Rules and Quark Model

We visited mass spectra and decay constants of pseudoscalar and vector heavy-light mesons (B, Bs, D, and DS) in the framework of QCD sum rule and quark model. The harmonic oscillator wave function was used in quark model while a simple interpolating current was used in QCD sum rule calculation. We obtained good results in accordance with the available experimental data and theoretical studies.

Mass spectrum and decay properties of heavy-light mesons: D, Ds, B and Bs mesons

We present a study of mass spectrum and decay properties of heavy-light mesons in the non-relativistic potential model. We consider a new type of potential for the mesonic system, the combination of harmonic and Yukawa-type potentials. To obtain the wave function of the system, we use the perturbation method. We take the harmonic term as parent and the Yukawa term as perturbation for the generation of wave function for the meson. For calculating the parent wave function, the Nikiforov-Uvarov (NU) approach is used and thereby we obtained a series solution for the perturbative wave function and then reported the total wave function. With this wave function, we then study the mass spectrum, the decay constant, the leptonic and semileptonic decay widths of heavy-light mesons.

Decay Constants of Heavy-Light Mesons from QCD

We summarize our recently improved results for the pseudoscalar [S. Narison, Phys.Lett. B718 (2013) 132; S. Narison, Nucl. Phys. Proc. Suppl. 234 (2013) 187; S. Narison, Phys.Lett. B721 (2013) 269], vector and Bc [S. Narison, Int. J. Mod. Phys. A30 (2015) 20, 1550116] meson decay constants from QCD spectral sum rules where N2LO⊕ estimate of the N3LO PT⊕d≤6 condensates have been included in the SVZ expansion. The “optimal results” based on stability criteria with respect to the variations of the Laplace/Moments sum rule variables, QCD continuum threshold and subtraction constant μ are compared with recent sum rules and lattice calculations. To understand the “apparent tension” between some recent results, we present in Section 8 a novel extraction of forfB⁎/fBfrom heavy quark effective theory (HQET) sum rules by including the normalization factor (Mb/MB)2 relating the pseudoscalar to the universal HQET correlators for finite b-quark and B-meson masses. We obtain fB⁎/fB=1.025(16) in good agreement with 1.016(16) from spectral sum rules (SR) in full QCD [3]. We complete the paper by including new improved estimates of the scalar, axial andBc⁎meson decay constants (Sections 11–13). For further phenomenological uses, we attempt to extract a Global Average of the sum rules and lattice determinations which are summarized in Tables 2–6. We do not found any deviation of these SM results from the present data.

Erratum: Decay constants of heavy-light vector mesons from QCD sum rules [Phys. Rev. D88, 014015 (2013)

Erratum: Decay constants of heavy-light vector mesons from QCD sum rules [Phys. Rev. D<b>88</b>, 014015 (2013)

Erratum: Decay constants of heavy-light vector mesons from QCD sum rules [Phys. Rev. D 88, 014015 (2013)

Erratum: Decay constants of heavy-light vector mesons from QCD sum rules [Phys. Rev. D 88, 014015 (2013)

Decay constants of heavy-light vector mesons from QCD sum rules

We revisit QCD sum rules for the decay constants of heavy-light mesons. In the sum rules for the vector mesons ${B}_{(s)}^{*}$ and ${D}_{(s)}^{*}$ we improve the accuracy of OPE, taking into account the $O({\ensuremath{\alpha}}_{s}^{2})$ terms in the perturbative part and calculating the $O({\ensuremath{\alpha}}_{s})$ corrections to the quark-condensate contribution. With this accuracy, we obtain the ratios of decay constants: ${f}_{{B}^{*}}/{f}_{B}={1.02}_{\ensuremath{-}0.03}^{+0.07}$, ${f}_{{D}^{*}}/{f}_{D}={1.20}_{\ensuremath{-}0.07}^{+0.10}$. The sum rule predictions for the decay constants of pseudoscalar mesons are updated with the results ${f}_{B}=({207}_{\ensuremath{-}9}^{+17})\text{ }\text{ }\mathrm{MeV}$, ${f}_{{B}_{s}}=({242}_{\ensuremath{-}12}^{+17})\text{ }\text{ }\mathrm{MeV}$, ${f}_{D}=({201}_{\ensuremath{-}13}^{+12})\text{ }\text{ }\mathrm{MeV}$, ${f}_{{D}_{s}}=({238}_{\ensuremath{-}23}^{+13})\text{ }\text{ }\mathrm{MeV}$. In order to assess the sensitivity of our calculation to the form of the sum rule, we consider alternative versions such as the power moments and Borel sum rules with different weights of the spectral density. We also investigated the heavy-quark limit of the sum rules for vector and pseudoscalar mesons, estimating the violations of the heavy-quark spin and flavor symmetry.

Hadron properties in AdS/QCD

We discuss a holographic soft-wall model developed for the description of mesons and baryons with adjustable quantum numbers n,J,L,S. This approach is based on an action which describes hadrons with broken conformal invariance and which incorporates confinement through the presence of a background dilaton field. Results obtained for heavy-light meson masses and decay constants are consistent with predictions of HQET. In the baryon sector, applications to the baryon masses, nucleon electromagnetic form factors and generalized parton distributions are discussed.

Nonperturbative QCD simulations with2+1flavors of improved staggered quarks

Dramatic progress has been made over the last decade in the numerical study of quantum chromodynamics (QCD) through the use of improved formulations of QCD on the lattice (improved actions), the development of new algorithms, and the rapid increase in computing power available to lattice gauge theorists. In this article simulations of full QCD are described using the improved staggered quark formalism, ``asqtad'' fermions. These simulations were carried out with two degenerate flavors of light quarks (up and down) and with one heavier flavor, the strange quark. Several light quark masses, down to about three times the physical light quark mass, and six lattice spacings have been used. These enable controlled continuum and chiral extrapolations of many low energy QCD observables. The improved staggered formalism is reviewed, emphasizing both advantages and drawbacks. In particular, the procedure for removing unwanted staggered species in the continuum limit is reviewed. Then the asqtad lattice ensembles created by the MILC Collaboration are described. All MILC lattice ensembles are publicly available, and they have been used extensively by a number of lattice gauge theory groups. The physics results obtained with them are reviewed, and the impact of these results on phenomenology is discussed. Topics include the heavy quark potential, spectrum of light hadrons, quark masses, decay constants of light and heavy-light pseudoscalar mesons, semileptonic form factors, nucleon structure, scattering lengths, and more.

A proposal for B-physics on current lattices

A method to extract B-physics parameters (b-quark mass and f B , $ {f_{{B_s}}} $ decay constants) from currently available lattice data is presented and tested. The approach is based on the idea of constructing appropriate ratios of heavy-light meson masses and decay constants, respectively, possessing a precisely known static limit, and evaluating them at various pairs of heavy quark masses around the charm. Via a smooth interpolation in the heavy quark mass from the easily accessible charm region to the asymptotic point, B-physics parameters are computed with a few percent (statistical + systematic) error using recently produced N f = 2 maximally twisted Wilson fermions data.

Moving nonrelativistic QCD for heavy-to-light form factors on the lattice

We formulate nonrelativistic quantum chromodynamics (NRQCD) on a lattice which is boosted relative to the usual discretization frame. Moving NRQCD allows us to treat the momentum for the heavy quark arising from the frame choice exactly. We derive moving NRQCD through $\mathcal{O}(1/{m}^{2},{v}_{\mathrm{rel}}^{4})$, as accurate as the NRQCD action in present use, both in the continuum and on the lattice with $\mathcal{O}({a}^{4})$ improvements. We have carried out extensive tests of the formalism through calculations of two-point correlators for both heavy-heavy (bottomonium) and heavy-light (${B}_{s}$) mesons in $2+1$ flavor lattice QCD and obtained nonperturbative determinations of energy shift and external momentum renormalization. Comparison to perturbation theory at $\mathcal{O}({\ensuremath{\alpha}}_{s})$ is also made. The results demonstrate the effectiveness of moving NRQCD. In particular we show that the decay constants of heavy-light and heavy-heavy mesons can be calculated with small systematic errors up to much larger momenta than with standard NRQCD.

Spectrum and decay constants of heavy-light mesons

Heavy-light mesons masses and decay constants are calculated within the framework of the field correlator model. Good agreement is obtained with the experimental data.

Heavy-strange meson decay constants in the continuum limit of quenched QCD

We improve a previous quenched result for heavy-light pseudoscalar meson decay constants with the light quark taken to be the strange quark. A finer lattice resolution (a ? 0.05 fm) in the continuum limit extrapolation of the data computed in the static approximation is included. We also give further details concerning the techniques used in order to keep the statistical and systematic errors at large lattice sizes L/a under control. Our final result, obtained by combining these data with determinations of the decay constant for pseudoscalar mesons around the Ds, follows nicely the qualitative expectation of the 1/m-expansion with a (relative) 1/m-term of about ?0.5GeV/mPS. At the physical b-quark mass we obtain FBs = 193(7)MeV, where all errors apart from the quenched approximation are included.

Running mass m s at low scale from the heavy-light meson decay constants

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 observed in the CLEO experiment, and $\eta_B=f_{B_s}/f_B\approx 1.20$, obtained in unquenched lattice QCD, can be reached only if the running mass $m_s$ at low scale is $m_s(\sim 0.5 $ GeV)$= 170 - 200$ MeV. Our results follow from the analytical expression for the pseudoscalar decay constant $f_{\rm P}$ based on the path-integral representation of the meson Green's function.

CURRENT PHYSICS RESULTS FROM STAGGERED CHIRAL PERTURBATION THEORY

We review several results that have been obtained using lattice QCD with the staggered quark formulation. Our focus is on the quantities that have been calculated numerically with low statistical errors and have been extrapolated to the physical quark mass limit and continuum limit using staggered chiral perturbation theory. We limit our discussion to a brief introduction to staggered quarks, and applications of staggered chiral perturbation theory to the pion mass, decay constant, and heavy–light meson decay constants.

Heavy-light decay constants using clover valence quarks and three flavors of dynamical improved staggered quarks

Starting in 2001, the MILC Collaboration began a large scale calculation of heavy-light meson decay constants using clover valence quarks on esembles of three flavor configurations. For the coarse configurations, with a = 0.12 fm , eight combinations of dynamical light and strange quarks have been analyzed. For the fine configurations, with a = 0.09 fm , three combinations of quark masses are studied. Since we last reported on this calculation, statistics have been increased on the fine ensembles, and, more importantly, a preliminary value fir the perturbative renormalization of the axial-vector current has become available. Thus, results for f B , f B s , f D and f D s can, in principle, be calculated in MeV, in addition to decay-constant ratios that were calculated previously.

Progress calculating decay constants with NRQCD and AsgTad actions

Abstract We combine a light AsgTad antiquark with a nonrelativistic heavy quark to compute the decay constants of heavy-light pseudoscalar mesons using the ensemble of 3-flavor gauge field configurations generated by the MILC collaboration. Preliminary results for f B s and f D s are given and status of the chiral extrapolation to f B is reported. We also touch upon results of the perturbative calculation which matches matrix elements in the effective theory to the full theory at 1-loop order.