Showing papers on "Meson published in 2003"
TL;DR: In this article, a comprehensive study of exclusive hadronic B -meson decays into final states containing two pseudoscalar mesons (PP) and a vector meson (PV) is presented.
797 citations
TL;DR: In this paper, the meson spectrum of an = 2 super Yang-Mills theory with fundamental matter from its dual string theory on AdS5 × S5 with a D7-brane probe was computed.
Abstract: We compute the meson spectrum of an = 2 super Yang-Mills theory with fundamental matter from its dual string theory on AdS5 × S5 with a D7-brane probe [1]. For scalar and vector mesons with arbitrary R-charge the spectrum is computed in closed form by solving the equations for D7-brane fluctuations; for matter with non-zero mass mq it is discrete, exhibits a mass gap of order mq/(gsN)1/2 and furnishes representations of SO(5) even though the manifest global symmetry of the theory is only SO(4). The spectrum of mesons with large spin J is obtained from semiclassical, rotating open strings attached to the D7-brane. It displays Regge-like behaviour for J > (gsN)1/2 it corresponds to that of two non-relativistic quarks bound by a Coulomb potential. Meson interactions, baryons and `giant gauge bosons' are briefly discussed.
506 citations
TL;DR: In this paper, the authors observed a narrow state near 2.32 GeV/c(2) in the inclusive D(+)(s)pi(0) invariant mass distribution from e(+)e(-) annihilation data at energies near 10.6 GeV.
Abstract: We have observed a narrow state near 2.32 GeV/c(2) in the inclusive D(+)(s)pi(0) invariant mass distribution from e(+)e(-) annihilation data at energies near 10.6 GeV. The observed width is consistent with the experimental resolution. The small intrinsic width and the quantum numbers of the final state indicate that the decay violates isospin conservation. The state has natural spin-parity and the low mass suggests a J(P)=0(+) assignment. The data sample corresponds to an integrated luminosity of 91 fb(-1) recorded by the BABAR detector at the SLAC PEP-II asymmetric-energy e(+)e(-) storage ring.
497 citations
TL;DR: In this article, the meson spectrum of an N = 2 super Yang-Mills theory with fundamental matter from its dual string theory on AdS_5 x S_5 with a D7-brane probe is computed.
Abstract: We compute the meson spectrum of an N=2 super Yang-Mills theory with fundamental matter from its dual string theory on AdS_5 x S_5 with a D7-brane probe. For scalar and vector mesons with arbitrary R-charge the spectrum is computed in closed form by solving the equations for D7-brane fluctuations; for matter with non-zero mass m_q it is discrete, exhibits a mass gap of order m_q / sqrt(g_s N) and furnishes representations of SO(5) even though the manifest global symmetry of the theory is only SO(4). The spectrum of mesons with large spin J is obtained from semiclassical, rotating open strings attached to the D7-brane. It displays Regge-like behaviour for J > sqrt(g_s N) it corresponds to that of two non-relativistic quarks bound by a Coulomb potential. Meson interactions, baryons and `giant gauge bosons' are briefly discussed.
456 citations
TL;DR: In this article, the relativistic corrections of order (v}^{2/c}^{ 2), including retardation effects and one-loop radiative corrections, are systematically taken into account in the computations of the mass spectra.
Abstract: The mass spectra and electromagnetic decay rates of charmonium, bottomonium, and ${B}_{c}$ mesons are comprehensively investigated in the relativistic quark model. The presence of only heavy quarks allows the expansion in powers of their velocities. All relativistic corrections of order ${v}^{2}{/c}^{2},$ including retardation effects and one-loop radiative corrections, are systematically taken into account in the computations of the mass spectra. The obtained wave functions are used for the calculation of radiative magnetic dipole $(M1)$ and electric dipole $(E1)$ transitions. It is found that relativistic effects play a substantial role. Their account and the proper choice of the Lorentz structure of the quark-antiquark interaction in a meson is crucial for bringing theoretical predictions in accord with experimental data. A detailed comparison of the calculated decay rates and branching fractions with available experimental data for radiative decays of charmonium and bottomonium is presented. The possibilities to observe the currently missing spin-singlet S and P states as well as D states in bottomonium are discussed. The results for ${B}_{c}$ masses and decays are compared with other quark model predictions.
333 citations
TL;DR: In this article, it was shown that in the restricted class of models with minimal flavour violation (MFV) in which only the SM low energy operators are relevant, the ratios Br (B q →μ μ )/ Δ M q ( q = s, d ) do not depend on F B q and the CKM matrix elements.
237 citations
TL;DR: In this paper, the authors studied decay mechanisms unique to flavor-singlet states, such as their coupling to gluons or their intrinsic charm, in the context of QCD factorization and heavy-quark expansion.
205 citations
TL;DR: In this paper, the authors report on measurements of differential cross sections dsigma/dp(T) for prompt charm meson production in ppmacr; collisions at sqrt[s]=1.96 TeV using 5.8+/-0.3 pb(-1) of data from the CDF II detector at the Fermilab Tevatron.
Abstract: We report on measurements of differential cross sections dsigma/dp(T) for prompt charm meson production in ppmacr; collisions at sqrt[s]=1.96 TeV using 5.8+/-0.3 pb(-1) of data from the CDF II detector at the Fermilab Tevatron. The data are collected with a new trigger that is sensitive to the long lifetime of hadrons containing heavy flavor. The charm meson cross sections are measured in the central rapidity region |y| K-pi(+), D(*+)-->D0pi(+), D+-->K-pi(+)pi(+), D(+)(s)-->phipi(+), and their charge conjugates. The measured cross sections are compared to theoretical calculations.
193 citations
CERN1
TL;DR: In this paper, the experimental searches and determinations of direct CP violation in meson decays and other systems are reviewed and a review of the experimental results is presented, as well as a discussion of CP violations in other systems.
Abstract: We review the experimental searches and determinations of direct CP violation in meson decays and other systems.
174 citations
TL;DR: In this paper, the authors evaluate strong decay amplitudes and partial widths of strange mesons (strangeonia and kaonia) in the quark model up to ca. 2.2 GeV.
Abstract: In this paper we evaluate strong decay amplitudes and partial widths of strange mesons (strangeonia and kaonia) in the ${}^{3}{P}_{0}$ decay model. We give numerical results for all energetically allowed open-flavor two-body decay modes of all $n\overline{s}$ and $s\overline{s}$ strange mesons in the $1S,$ $2S,$ $3S,$ $1P,$ $2P,$ $1D$ and $1F$ multiplets, comprising strong decays of a total of 43 resonances into 525 two-body modes, with 891 numerically evaluated amplitudes. This set of resonances includes all strange $q\overline{q}$ states with allowed strong decays expected in the quark model up to ca. 2.2 GeV. We use standard nonrelativistic simple harmonic oscillator quark model wave functions to evaluate these amplitudes, and quote numerical results for all amplitudes present in each decay mode. We also discuss the status of the associated experimental candidates, and note which states and decay modes would be especially interesting for future experimental study at hadronic, ${e}^{+}{e}^{\ensuremath{-}}$ and photoproduction facilities. These results should also be useful in distinguishing conventional quark model mesons from exotica such as glueballs and hybrids through their strong decays.
161 citations
TL;DR: In this paper, the relativistic meson wave functions are used for the calculation of the decay rates of the meson to charmonium and D mesons, and the decay form factors are explicitly expressed through the overlap integrals of the wave functions in the whole accessible kinematical range.
Abstract: Semileptonic and nonleptonic decays of the ${B}_{c}$ meson to charmonium and D mesons are studied in the framework of the relativistic quark model. The decay form factors are explicitly expressed through the overlap integrals of the meson wave functions in the whole accessible kinematical range. The relativistic meson wave functions are used for the calculation of the decay rates. The obtained results are compared with the predictions of other approaches.
TL;DR: In this article, the authors calculate the Sudakov factors in the large-recoil limit in the perturbative QCD approach, including both the vector (axial vector) and tensor operators.
Abstract: We calculate the $B\to P$
, $B\to V$
(P is the light pseudoscalar meson, V the light vector meson) form factors in the large-recoil limit in the perturbative QCD approach, including both the vector (axial vector) and tensor operators. In general there are two leading components $\phi_B$
and $\bar{\phi}_B$
for the B meson wave functions. We consider both contributions of them. Sudakov effects (
$k_{\perp}$
and threshold resummation) are included to regulate the soft end-point singularity. By choosing the hard scale as the maximum virtualities of the internal particles in the hard b quark decay amplitudes, Sudakov factors can effectively suppress the long-distance soft contribution. The hard contribution can be dominant in these approaches.
TL;DR: In this paper, the authors compute the next-to-leading order QCD corrections to the off-diagonal elements of the decay-width matrix Γ entering the neutral B-meson oscillations.
Abstract: We compute the next-to-leading order QCD corrections to the off-diagonal elements of the decay-width matrix Γ entering the neutral B-meson oscillations. From this calculation the width differences ΔΓ and the CP violation parameters (q/p) of B d and B s mesons are estimated, including the complete (αs) QCD corrections and the 1/m b contributions. For the width difference ΔΓs we agree with previous results. By using the lattice determinations of the relevant hadronic matrix elements we obtain the theoretical predictions ΔΓ d /Γ d = (2.42±0.59) × 10−3 and ΔΓ s /Γ s = (7.4±2.4) × 10−2 . For the CP violation parameters, we find |(q/p) d |−1 = (2.96±0.67) × 10−4 and |(q/p) s |−1 = −(1.28±0.27) × 10−5 . These predictions are compatible with the experimental measurements which, however, suffer at present from large uncertainties.
TL;DR: In this article, a review of the state-of-the-art results for low-lying nucleon resonances can be found, focusing on experiments aiming at precise studies of the low lying nucleon resonance.
TL;DR: First measurements of low-mass electron-positron pairs in Pb-Au collisions at the CERN SPS beam energy of 40 AGeV support the notion that the in-medium modifications of the rho are more driven by baryon density than by temperature.
Abstract: We report on first measurements of low-mass electron-positron pairs in Pb-Au collisions at the CERN SPS beam energy of 40 AGeV. The observed pair yield integrated over the range of invariant masses 0.2 < m ≤ 1 GeV/c 2 is enhanced over the expectation from neutral meson decays by a factor of 5.9 ′ 1.5(stat) ′ 1.2(syst data) ′ 1.8(syst meson decays), somewhat larger than previously observed at the higher energy of 158 AGeV. The results are discussed with reference to model calculations based on π + π - → e + e - annihilation with a modified p propagator. They may be linked to chiral symmetry restoration and support the notion that the in-medium modifications of the p are more driven by baryon density than by temperature.
TL;DR: In this paper, the odd-intrinsic-parity effective lagrangian of QCD is analyzed for processes involving one pseudoscalar with vector mesons described in terms of antisymmetric tensor fields.
Abstract: We analyse the most general odd-intrinsic-parity effective lagrangian of QCD valid for processes involving one pseudoscalar with vector mesons described in terms of antisymmetric tensor fields. Substantial information on the odd-intrinsic-parity couplings is obtained by constructing the vector-vector-pseudoscalar Green's three-point function, at leading order in 1/NC, and demanding that its short-distance behaviour matches the corresponding OPE result. The QCD constraints thus enforced allow us to predict the decay amplitudes ω→πγ and ρ→πγ, and the (p6) corrections to π→γγ. Noteworthy consequences concerning the vector meson dominance assumption in the decay ω→3π are also extracted from the previous analysis.
TL;DR: In this article, the SU(3) breaking effect on meson-baryon scattering amplitudes in the chiral unitary model was examined and it was shown that it cannot explain the channel dependence of the subtraction parameters of the model.
Abstract: We examine flavor SU(3) breaking effects on meson-baryon scattering amplitudes in the chiral unitary model. It turns out that the SU(3) breaking, which appears in the leading quark mass term in the chiral expansion, cannot explain the channel dependence of the subtraction parameters of the model, which are crucial for reproducing the observed scattering amplitudes and resonance properties.
TL;DR: It is shown that in strongly coupled N=4 supersymmetric Yang-Mills conformal theory the binding energy of a heavy and a light quark is independent of the strength of the coupling constant, and the analog of the QCD string can snap and color charges are screened.
Abstract: We show that in strongly coupled $\mathcal{N}=4$ supersymmetric Yang-Mills conformal theory the binding energy of a heavy and a light quark is independent of the strength of the coupling constant. As a consequence we are able to show that in the presence of light quarks the analog of the QCD string can snap and color charges are screened. The resulting neutral mesons interact with each other only via pion exchange and we estimate the masses of those states.
TL;DR: In this article, a soft-collinear effective theory is generalized to include soft massless quarks in addition to collinear fields, which is necessary for the treatment of interactions with the soft spectator quark in a heavy meson.
TL;DR: In this paper, the authors compute the next-to-leading order QCD corrections to the off-diagonal elements of the decay-width matrix Gamma entering the neutral B-meson oscillations.
Abstract: We compute the next-to-leading order QCD corrections to the off-diagonal elements of the decay-width matrix Gamma entering the neutral B-meson oscillations. From this calculation the width differences DeltaGamma and the CP violation parameters (q/p) of Bd and Bs mesons are estimated, including the complete O}(alpha_s) QCD corrections and the 1/mb contributions. For the width difference DeltaGamma_s we agree with previous results. By using the lattice determinations of the relevant hadronic matrix elements we obtain the theoretical predictions DeltaGamma_d/Gamma_d=(2.42+-0.59) x 10^(-3) and DeltaGamma_s/Gamma_s=(7.4+-2.4) x 10^(-2). For the CP violation parameters, we find |(q/p)_d|-1=(2.96+-0.67) x 10^(-4) and |(q/p)_s|-1=(-1.28+-0.27) x 10^(-5). These predictions are compatible with the experimental measurements which, however, suffer at present from large uncertainties.
TL;DR: In this paper, a covariant coalescence model was proposed to describe the hadron production in relativistic heavy ion collisions from both soft partons in the quark-gluon plasma and hard partons of minijets.
Abstract: Using a covariant coalescence model, we study hadron production in relativistic heavy ion collisions from both soft partons in the quark-gluon plasma and hard partons in minijets. Including transverse flow of soft partons and independent fragmentation of minijet partons, the model is able to describe available experimental data on pion, kaon, and antiproton spectra. The resulting antiproton to pion ratio is seen to increase at low transverse momenta and reaches a value of about 1 at intermediate transverse momenta, as observed in experimental data at RHIC. A similar dependence of the antikaon to pion ratio on transverse momentum is obtained, but it reaches a smaller value at intermediate transverse momenta. At high transverse momenta, the model predicts that both the antiproton to pion and the antikaon to pion ratio decrease and approach those given by the perturbative QCD. Both collective flow effect and coalescence of minijet partons with partons in the quark-gluon plasma affect significantly the spectra of hadrons with intermediate transverse momenta. Elliptic flows of phi mesons and baryons such as protons, lambdas, cascades, and omegas have also been evaluated from partons with elliptic flows extracted from fitting measured pion and kaon elliptic flows. The predicted proton and lambda elliptic flows are consistent with available experimental data.
TL;DR: The D s (2320) state recently observed by BaBar in the D s + π 0 channel may be the first of a host of cq q q q four-quark states.
TL;DR: In this article, the authors present the results of the current analysis of the partial wave IJPC = 00+ + based on the available data for meson spectra ( ππ, K¯K, ηη,η\(\),πππPπ), in the framework of the K-matrix approach, the analytical amplitude has been reconstructed in the mass region 280 MeV < \(\) < 1900 MeV.
Abstract: We present the results of the current analysis of the partial wave IJPC = 00+ + based on the available data for meson spectra ( ππ, K¯K,ηη,η\(\),ππππ). In the framework of the K-matrix approach, the analytical amplitude has been reconstructed in the mass region 280 MeV < \(\) < 1900 MeV. The following scalar-isoscalar states are seen: comparatively narrow resonances f0(980), f0(1300), f0(1500), f0(1750) and the broad state f0(1200-1600). The positions of the amplitude poles (masses and total widths of the resonances) are determined as well as pole residues (partial widths to meson channels ππ, K¯K,ηη,η\(\),ππππ). The fitted amplitude gives us the positions of the K-matrix poles (bare states) and the values of bare-state couplings to meson channels thus allowing the quark-antiquark nonet classification of bare states. On the basis of the obtained partial widths to the channels ππ, K¯K,ηη,η\(\), we estimate the quark/gluonium content of f0(980), f0(1300), f0(1500), f0(1750), f0(1200-1600). For f0(980), f0(1300), f0(1500) and f0(1750), their partial widths testify the q¯q origin of these mesons though being unable to provide precise evaluation of the possible admixture of the gluonium component in these resonances. The ratios of the decay coupling constants for the f0(1200-1600) support the idea about the gluonium nature of this broad state.
TL;DR: In this paper, the authors analyzed the hadronic and radiative decay modes of the recently observed DsJ(2317) meson, in the hypothesis that it can be identified with the scalar s l P = 1 2 + state of c s spectrum (Ds0).
TL;DR: In this article, the FONLL approach in perturbative QCD was used to calculate the D*+, D+ and D0 meson single inclusive production cross section for the Tevatron Run II.
Abstract: We present a calculation of the D*+, D+ and D0 meson single inclusive production cross section for the Tevatron Run II. We use the FONLL approach in perturbative QCD, which, besides including the known next-to-leading order corrections, also provides for the resummation at the next-to-leading logarithmic level of terms enhanced at large pT by powers of log (pT/m), where m is the charm mass and pT is its transverse momentum. Non-perturbative effects in charm hadronization are extracted, in moment space, from recent ALEPH data for D* fragmentation in e+e? collisions.
TL;DR: In this article, the pi-N interaction is studied within a meson exchange model and in a coupled-channels approach which includes the channels pi, eta-N, as well as three effective pi-pi-N channels.
Abstract: The pi-N interaction is studied within a meson-exchange model and in a coupled-channels approach which includes the channels pi-N, eta-N, as well as three effective pi-pi-N channels namely rho-N, pi-Delta, and sigma-N. Starting out from an earlier model of the Julich group systematic improvements in the dynamics and in some technical aspects are introduced. With the new model an excellent quantitative reproduction of the pi-N phase shifts and inelasticity parameters in the energy region up to 1.9 GeV and for total angular momenta J leq 3/2 is achieved. Simultaneously, good agreement with data for the total and differential pi-N -> eta-N transition cross sections is obtained. The connection of the pi_N dynamics in the S_{11} partial wave with the reaction pi-N -> eta-N is discussed.
TL;DR: In this article, the soft hadronic component of the photon was used to calculate corrections to the factorized expression which are induced by the ''soft'' hadronic components of photon and showed that these corrections are numerically not effective for physical values of the $b$ quark mass.
Abstract: B->gamma e nu transitions have recently been studied in the framework of QCD factorization The attractiveness of this channel for such an analysis lies in the fact that, at least in the heavy quark limit, the only hadron involved is the B meson itself, so one expects a very simple description of the form factor in terms of a convolution of the B meson distribution amplitude with a perturbative kernel This description, however, does not include contributions suppressed by powers of the b quark mass In this letter, we calculate corrections to the factorized expression which are induced by the ``soft'' hadronic component of the photon We demonstrate that the power-suppression of these terms is numerically not effective for physical values of the $b$ quark mass and that they increase the form factor by about 30% at zero momentum transfer We also derive a sum rule for lambda_B, the first negative moment of the B meson distribution amplitude, and find lambda_B = 06 GeV (to leading order in QCD)
TL;DR: The charge form factor of the neutron was determined from asymmetries measured in quasi-elastic 3He(e→,e′n) at a momentum transfer of 067 (GeV/c).
TL;DR: In this article, the authors examined the properties of generalized quarkonium with light adjoint particles and showed that these hadrons are unlike any known in QCD, and that they appear infinite in size, but this is a failure of the yardstick.
Abstract: Adding fundamental matter of mass m_Q to N=4 Yang Mills theory, we study quarkonium, and "generalized quarkonium" containing light adjoint particles. At large 't Hooft coupling the states of spin<=1 are anomalously light (Kruczenski et al., hep-th/0304032). We examine their form factors, and show these hadrons are unlike any known in QCD. By a traditional yardstick they appear infinite in size (as with strings in flat space) but we show that this is a failure of the yardstick. All of the hadrons are actually of finite size ~ \sqrt{g^2N}/m_Q, regardless of their radial excitation level and of how many valence adjoint particles they contain. Certain form factors for spin-1 quarkonia vanish in the large-g^2N limit; thus these hadrons resemble neither the observed J/Psi quarkonium states nor rho mesons.
TL;DR: In this article, the relativistic Hartree approach describing the bound states of both nucleons and antinucleons in finite nuclei has been extended to include tensor couplings for the omega and rho mesons.
Abstract: The relativistic Hartree approach describing the bound states of both nucleons and antinucleons in finite nuclei has been extended to include tensor couplings for the omega and rho mesons. After readjusting the parameters of the model to the properties of spherical nuclei, the effect of tensor-coupling terms raises the spin-orbit force by a factor of 2, while a large effective nucleon mass m*/M(N)approximate to0.8 sustains. The overall nucleon spectra of shell-model states are improved evidently. The predicted antinucleon spectra in the vacuum are deepened about 20-30 MeV.