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.
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.
209955454
Charmed hadron interactions
16924371
The cosmological origin of Higgs particles
A proposal of the cosmological origin of Higgs particles is given. We show, that the Higgs field could be created from the vacuum quantum conformal fluctuation of Anti-de Sitter space-time, the spontaneous breaking of vacuum symmetry, and the mass of Higgs particle are related to the cosmological constant of our universe,especially the theoretical estimated mass m$_{H}$ of Higgs particles is m$_{H}=\sqrt{-2\mu ^{2}}$ =$\sqrt{|\Lambda /\pi}$.
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.
16274144
On the Gravitational Wave in de Sitter Spacetime
For there is always a wrong sign in the mass of graviton in the so-called perturbation expansion approximation of both Minkowski and de Sitter spacetimes, the existence of gravitational wave from the metric perturbation of de Sitter spacetime is doubtful. We try another way to start from the assumption that the gravitational wave equation should be both general covariant and conformal invariant and find that graviton is no longer a part of metric field, it has an effective mass of $m_g=\sqrt{R/6}=% \sqrt{2\Lambda/3}$ with correct sign in de Sitter spacetime, though it's intrinsic mass remains zero.
119090662
Sommerfeld's quantum condition of action and the spectra of Schwarzschild black hole
If the situation of quantum gravity nowadays is nearly the same as that of the quantum mechanics in it's early time of Bohr and Sommerfeld, then a first step study of the quantum gravity from Sommerfeld's quantum condition of action might be helpful. In this short paper the spectra of Schwarzschild black hole(SBH) in quasi-classical approach of quantum mechanics is given. We find the quantum of area, the quantum of entropy and the Hawking evaporation will cease as the black hole reaches its ground state.
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.