123462870
Excited and exotic charmonium spectroscopy from lattice QCD
We study the charmonium spectrum in full QCD on anisotropic lattices generated by Hadron Spectrum Collaboration. We adopt a large basis of interpolating operators to extract the excited charmonium states using the variational method. A detailed spectrum of excited charmonium mesons in many J{sup PC} channels is obtained. Some exotic hybrid states ( with J{sup PC} = 0{sup +-} , 1{sup -+} , 2{sup +-}) are also studied
11641258
Charmed Hadron Interactions
We compute the scattering lengths of charmed mesons and charmonia scattering with light hadrons in full QCD. We use Fermilab formulation for the charm quark and domain-wall fermions for the light quarks and staggered sea quarks. Four different light-quark masses are used to extrapolate to the physical point. The charmed baryon spectrum is also presented.
204005840
Quenched charmed meson spectra using tadpole improved quark action on anisotropic lattices
Charmed meson charmonium spectra are studied with improved quark actions on anisotropic lattices. We measured the pseudo-scalar and vector meson dispersion relations for four lowest lattice momentum modes with quark mass values ranging from the strange quark to charm quark with three different values of gauge coupling β and four different values of bare speed of light ν. With the bare speed of light parameter ν tuned in a mass-dependent way, we study the mass spectra of D, Ds, ηc, D*, Ds* and J/ψ mesons. The results extrapolated to the continuum limit are compared with the experiment, and a qualitative agreement is found.
119269752
Singly and Doubly Charmed $J=1/2$ Baryon Spectrum from Lattice QCD
We compute the masses of the singly and doubly charmed baryons in full QCD using the relativistic Fermilab action for the charm quark. For the light quarks we use domain-wall fermions in the valence sector and improved Kogut-Susskind sea quarks. We use the low-lying charmonium spectrum to tune our heavy-quark action and as a guide to understanding the discretization errors associated with the heavy quark. Our results are in good agreement with experiment within our systematics. For the {Xi}{sub cc}, we find the isospin-averaged mass to be M{sub {Xi}{sub c{sub c}}}=3665{+-}17{+-}14{sub -78}{sup +0} MeV; the three given uncertainties are statistical, systematic, and an estimate of lattice discretization errors, respectively. In addition, we predict the mass splitting of the (isospin-averaged) spin-1/2 {Omega}{sub cc} with the {Xi}{sub cc} to be M{sub {Omega}{sub c{sub c}}}-M{sub {Xi}{sub c{sub c}}}=98{+-}9{+-}22{+-}13 MeV (in this mass splitting, the leading discretization errors are also suppressed by SU(3) symmetry). Combining this splitting with our determination of M{sub {Xi}{sub c{sub c}}} leads to our prediction of the spin-1/2 {Omega}{sub cc} mass, M{sub {Omega}{sub c{sub c}}}=3763{+-}19{+-}26{sub -79}{sup +13} MeV.
53386989
Interactions of Charmed Mesons with Light Pseudoscalar Mesons from Lattice QCD and Implications on the Nature of the $D_{s0}^*(2317)$
We study the scattering of charmed mesons (D, D{sub s}) with light pseudoscalar mesons ({pi}, K) in full lattice QCD. The S-wave scattering lengths are calculated using L{umlt u}schers finite volume technique. We use the relativistic Fermilab formulation for the charm quark. For the light quark, we use domain-wall fermions in the valence sector and improved Kogut-Susskind sea quarks. We calculate the scattering lengths of isospin-3/2 D{pi}, D{sub s}{pi}, D{sub s}K, isospin-0 D{anti K} and isospin-1 D{anti K} channels on the lattice. For the chiral extrapolation, we use the chiral unitary approach to next-to-leading order, which at the same time allows us to give predictions for other channels. Furthermore, the hadronic molecular interpretation of the D{sub s0}*(2317) is consistent with our results. The isospin breaking decay width {Gamma}(D{sub s0}*(2317){yields}D{sub s}{pi}) in the hadronic molecular picture is updated to be (89{+-}22)keV.
27115647
Tetraquarks, hadronic molecules, meson-meson scattering and disconnected contributions in lattice QCD
There are generally two types of Wick contractions in lattice QCD calculations of a correlation function: connected and disconnected ones. The disconnected contribution is difficult to calculate and noisy, thus it is often neglected. In the context of studying tetraquarks, hadronic molecules, and mesonmeson scattering, we show that whenever there are both connected and singly disconnected contractions, the singly disconnected part gives the leading order contribution, and thus should never be neglected. As an explicit example, we show that information about the scalar mesons sigma, f(0)(980), a(0)(980), and kappa will be lost when neglecting the disconnected contributions.
119217520
Moduli stabilisation in early superstring cosmology
We study the cosmological evolution induced by the free energy of a string gas at finite temperature. We first consider the maximally supersymmetric heterotic string in the weak coupling regime in dimension D ≥ 4. The free energy develops local minima associated to some gauge symmetry enhancement induced by perturbative states. This can stabilize all heterotic moduli except the dilaton. By string-string S-dualities, it follows that the dual type I moduli can be stabilized by either non perturbative D-string states or perturbative open string states. We next consider the type II string compactified on Calabi-Yau three-folds, which has = 2 supersymmetry in D = 4. The moduli space has singular loci where the Calabi-Yau space undergoes extremal transitions, accompanied with either conifold transitions or certain gauge symmetry enhancement. Also the free energy reaches local minima due to the emergence of extra non perturbative massless modes. Consequently, the type II moduli are attracted to these singular loci. Using the type II/heterotic string duality, we can stabilize the dual heterotic moduli, and in particular it is possible to stabilize the heterotic dilaton.
8230888
Measurement of the cross section for electromagnetic dissociation with neutron emission in Pb-Pb collisions at sqrt[s(NN)] = 2.76 TeV.
The first measurement of neutron emission in electromagnetic dissociation of ^{208}Pb nuclei at the LHC is presented. The measurement is performed using the neutron zero degree calorimeters of the ALICE experiment, which detect neutral particles close to beam rapidity. The measured cross sections of single and mutual electromagnetic dissociation of Pb nuclei at sqrt[s(NN)]=2.76 TeV with neutron emission are σ(singleEMD)=187.4 ± 0.2(stat)(-11.2)(+13.2) (syst) b and σ(mutualEMD) = 5.7 ± 0.1(stat) ± 0.4(syst) b, respectively. The experimental results are compared to the predictions from a relativistic electromagnetic dissociation model.
118580884
Could the Gravitons Have Rest Masses
If the cosmological constant $\Lambda $ can not be neglected, we will show in this short report, that graviton should have a rest mass $m_g=\sqrt{2\Lambda }=\sqrt{2\Lambda}\hbar c^{-1}$ different from zero.
118483349
Neutrino mixing in matter
Three-neutrino mixing in matter is studied through a set of evolution equations which are based on a rephasing invariant parametrization. Making use of the known properties of measured neutrino parameters, analytic, approximate solutions are obtained. Their accuracy is confirmed by comparison with numerical integration of these equations. The results, when expressed in the elements squared of the mixing matrix, exhibit striking patterns as the matter density varies.
118633437
NON-ABELIAN VORTEX-STRING DYNAMICS FROM NONLINEAR REALIZATION
The dynamics of the non-Abelian vortex-string, which describes its low energy oscillations into the target D = 3+1 space–time as well as its orientations in the internal space, is derived by the approach of nonlinear realization. The resulting action correlating these two sectors is found to have an invariant synthesis form of the Nambu–Goto-CPN-1 model actions. Higher order corrections to the vortex actions are presented up to the order of quartic derivatives. General p-brane dynamics in terms of the internal symmetry breaking is also discussed.