116438391
Search for $B_{s}^{0}\rightarrow\gamma\gamma$ and a measurement of the branching fraction for $B_{s}^{0}\rightarrow\phi\gamma$
We search for the decay $B_{s}^{0}\rightarrow\gamma\gamma$ and measure the branching fraction for $B_{s}^{0}\rightarrow\phi\gamma$ using 121.4~$\textrm{fb}^{-1}$ of data collected at the $\Upsilon(\mathrm{5}S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$ collider. The $B_{s}^{0}\rightarrow\phi\gamma$ branching fraction is measured to be $(3.6 \pm 0.5 (\mathrm{stat.}) \pm 0.3 (\mathrm{syst.}) \pm 0.6 (f_{s})) \times 10^{-5}$, where $f_{s}$ is the fraction of $B_{s}^{(*)}\bar{B}_{s}^{(*)}$ in $b\bar{b}$ events. Our result is in good agreement with the theoretical predictions as well as with a recent measurement from LHCb. We observe no statistically significant signal for the decay $B_{s}^{0}\rightarrow\gamma\gamma$ and set a $90\%$ confidence-level upper limit on its branching fraction at $ 3.1 \times 10^{-6}$. This constitutes a significant improvement over the previous result.
124556172
Searches for charmless decays $B^0 \to \eta \omega$, $B^0 \to \eta K^0$, $B^{+} \to \eta \rho^{+}$, and $B^{+} \to \eta^\prime \pi^{+}$
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.
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.
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.
118088369
Estimate for GLAST LAT Milky Way Dark Matter WIMP Line Sensitivity
The LAT Dark Matter and New Physics Working group has been developing approaches for the indirect astrophysical detection of annihilation of dark matter. Our work has assumed that a significant component of dark matter is a new type of Weakly Interacting Massive Particle (WIMP). The annihilation of two WIMPs usually results in the production of many high energy gamma rays (>1 GeV) that can be well measured in the GLAST LAT if present. There is also the possibility to observe γ lines from annihilation into γγ and or γZ final states. In popular SUSY theories these line decays occur at the 10−4 to 10−2 branching fraction level. Estimates of LAT sensitivity (at 5σ above background) and upper limits (upper limit at the 95% confidence level) to these WIMP lines will be presented. These sensitivities are given in photons/cm2/sec/sr and so do not depend on the WIMP models. However, they do depend on the diffuse background model. The latter is derived from GALPROP based on EGRET and other data in the EGRET energy ...
24034026
Strange electric form factor of the proton.
By combining the constraints of charge symmetry with new chiral extrapolation techniques and recent low-mass quenched lattice QCD simulations of the individual quark contributions to the electric charge radii of the baryon octet, we obtain an accurate determination of the strange electric charge radius of the proton. While this analysis provides a value for G(E)(s)(Q(2) = 0.1 GeV(2)) in agreement with the best current data, the theoretical error is comparable with that expected from future HAPPEX results from JLab. Together with the earlier determination of G(M)(s), this result considerably constrains the role of hidden flavor in the structure of the nucleon.
31587325
Fermi-LAT search for pulsar wind nebulae around gamma-ray pulsars
The high sensitivity of the Fermi-LAT (Large Area Telescope) offers the first opportunity to study faint and extended GeV sources such as pulsar wind nebulae (PWNe). After one year of observation the LAT detected and identified three pulsar wind nebulae: the Crab Nebula, Vela-X and the PWN inside MSH 15-52. In the meantime, the list of LAT detected pulsars increased steadily. These pulsars are characterized by high energy loss rates from ~3 \times 10^{33} erg s$^{-1}$ to 5 \times 10$^{38}$ erg s$^{-1}$ and are therefore likely to power a PWN. This paper summarizes the search for PWNe in the off-pulse windows of 54 LAT-detected pulsars using 16 months of survey observations. Ten sources show significant emission, seven of these likely being of magnetospheric origin. The detection of significant emission in the off-pulse interval offers new constraints on the gamma-ray emitting regions in pulsar magnetospheres. The three other sources with significant emission are the Crab Nebula, Vela-X and a new pulsar wind nebula candidate associated with the LAT pulsar PSR J1023-5746, coincident with the TeV source HESS J1023-575. We further explore the association between the H.E.S.S. and the Fermi source by modeling its spectral energy distribution. Flux upper limits derived for the 44 remaining sources are used to provide new constraints on famous PWNe that have been detected at keV and/or TeV energies.
119450769
Isospin dependence of liquid–gas phase transition in hot asymmetric nuclear matter
Abstract By using the Furnstahl, Serot and Tang's model, the effect of density dependence of the effective nucleon–nucleon– ρ -meson (NN ρ ) coupling on the liquid–gas phase transition in hot asymmetric nuclear matter is investigated. A limit pressure p lim has been found. We found that the liquid–gas phase transition cannot take place if p > p lim . The binodal surface for density dependent NN ρ coupling situation is addressed.
17647646
Strange quark matter in a chiral SU(3) quark mean field model
We apply the chiral SU(3) quark mean field model to investigate strange quark matter. The stability of strange quark matter with different strangeness fraction is studied. The interaction between quarks and vector mesons destabilizes the strange quark matter. If the strength of the vector coupling is the same as in hadronic matter, strangelets can not be formed. For the case of beta equilibrium, there is no strange quark matter which can be stable against hadron emission even without vector meson interactions.