119717624
Asymmetric nuclear matter at finite temperature and density
Asymmetric nuclear matter is studied by using an effective nuclear model in a mean-field approximation. The density, temperature, and asymmetric parameter dependence of the effective baryon mass is discussed. The liquid-gas phase transition of a system with two independent conserved charges (baryon number and isospin) is studied using the stability conditions on the free energy and Gibbs conditions for phase equilibrium. The critical temperature is calculated with and without $\ensuremath{\rho}$ meson contribution, respectively.
118501601
First observation of CP violation and improved measurement of the branching fraction and polarization of B0→D*+D*− decays
We report the measurement of the branching fraction, the polarization, and the parameters of the time-dependent CP violation in B-0 -> D*(+) D*(-) decays using a data sample of 772 x 10(6)B (B) over bar pairs, collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We obtain a branching fraction of B = (7.82 +/- 0.38 +/- 0.63) x 10(-4), a CP-odd fraction of R-perpendicular to = 0.138 +/- 0.024 +/- 0.006 and, additionally, a fraction of the longitudinal component in the transversity base of R-0 = 0.624 +/- 0.029 +/- 0.011. The measured values of the parameters of the CP violation are SD*+ D*- = 0.79 +/- 0.13 +/- 0.03 and A(D*+ D*-) 0.15 +/- 0.08 +/- 0.04.
21907946
Search for T, CP, and CPT violation in B0-B0 mixing with inclusive dilepton events.
We report the results of a search for T, CP, CPT, and violation in B0-B0 mixing using an inclusive dilepton sample collected by the BABAR experiment at the PEP-II factory. Using a sample of 232 x 10(6) BB pairs, we measure the T and CP violation parameter |q/p| - 1 = (-0.8 +/- 2.7(stat) +/- 1.9(syst) x 10(-3), and the CPT and CP parameters Imz = (13.9 +/- 7.3(stat) +/- 3.2(syst)) x 10(-3) and Delta Gamma x Rez = (7.1 +/- 3.9(stat) +/- 2.0(stat)) x 10(-3) ps(-1). The statistical correlation between the measurements of Imz and Delta Gamma x Rez is 76%.
120186826
Physics at BES-III
This physics book provides detailed discussions on important topics in $\tau$-charm physics that will be explored during the next few years at \bes3 . Both theoretical and experimental issues are covered, including extensive reviews of recent theoretical developments and experimental techniques. Among the subjects covered are: innovations in Partial Wave Analysis (PWA), theoretical and experimental techniques for Dalitz-plot analyses, analysis tools to extract absolute branching fractions and measurements of decay constants, form factors, and CP-violation and \DzDzb-oscillation parameters. Programs of QCD studies and near-threshold tau-lepton physics measurements are also discussed.
120311240
Observation of $J/\psi \rightarrow p\bar{p}a_{0}(980)$ at BESIII
Using $2.25\times10^{8}$ $J/\psi$ events collected with the BESIII detector at the BEPCII storage rings, we observe for the first time the process $J/\psi\rightarrow p\bar{p}a_{0}(980)$, $a_{0}(980)\rightarrow \pi^{0}\eta$ with a significance of $6.5\sigma$ ($3.2\sigma$ including systematic uncertainties). The product branching fraction of $J/\psi\rightarrow p\bar{p}a_{0}(980)\rightarrow p\bar{p}\pi^{0}\eta$ is measured to be $(6.8\pm1.2\pm1.3)\times 10^{-5}$, where the first error is statistical and the second is systematic. This measurement provides information on the $a_{0}$ production near threshold coupling to $p\bar{p}$ and improves the understanding of the dynamics of $J/\psi$ decays to four body processes.
124556172
Searches for charmless decays $B^0 \to \eta \omega$, $B^0 \to \eta K^0$, $B^{+} \to \eta \rho^{+}$, and $B^{+} \to \eta^\prime \pi^{+}$
53591668
Liquid-gas phase transition in nuclear matter including strangeness
We apply the chiral SU(3) quark mean field model to study the properties of strange hadronic matter at finite temperature. The liquid-gas phase transition is studied as a function of the strangeness fraction. The pressure of the system cannot remain constant during the phase transition, since there are two independent conserved charges (baryon and strangeness number). In a range of temperatures around 15 MeV (precise values depending on the model used) the equation of state exhibits multiple bifurcates. The difference in the strangeness fraction f{sub s} between the liquid and gas phases is small when they coexist. The critical temperature of strange matter turns out to be a nontrivial function of the strangeness fraction.
118407973
Solid quantization for non-point particles
In quantum field theory, elemental particles are assumed to be point particles. As a result, the loop integrals are divergent in many cases. Regularization and renormalization are necessary in order to get the physical finite results from the infinite, divergent loop integrations. We propose new quantization conditions for non-point particles. With this solid quantization, divergence could be treated systematically. This method is useful for effective field theory which is on hadron degrees of freedom. The elemental particles could also be non-point ones. They can be studied in this approach as well.
7419903
Chiral symmetry restoration in strange hadronic matter
The phase transition of chiral symmetry restoration in strange hadronic matter is studied in the chiral SU(3) quark mean field model. When the baryon density is larger than a critical density {rho}{sub c}, the minimal energy density of the system occurs at the point where the effective masses of nucleon, {lambda}, or {xi} drop to zero. The physical quantities change discontinuously at this density and the system will be in the phase of chiral symmetry restoration. A rich phase structure of strange hadronic matter with different strangeness fraction f{sub s} is obtained.
47886823
Fermi-LAT Study of Gamma-ray Emission in the Direction of Supernova Remnant W49B
We present an analysis of the gamma-ray data obtained with the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope in the direction of SNR W49B (G43.3-0.2). A bright unresolved gamma-ray source detected at a significance of 38 sigma is found to coincide with SNR W49B. The energy spectrum in the 0.2-200 GeV range gradually steepens toward high energies. The luminosity is estimated to be 1.5x10^{36} (D/8 kpc)^2 erg s^-1 in this energy range. There is no indication that the gamma-ray emission comes from a pulsar. Assuming that the SNR shell is the site of gamma-ray production, the observed spectrum can be explained either by the decay of neutral pi mesons produced through the proton-proton collisions or by electron bremsstrahlung. The calculated energy density of relativistic particles responsible for the LAT flux is estimated to be remarkably large, U_{e,p}>10^4 eV cm^-3, for either gamma-ray production mechanism.
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.