125575431
Measurement of the branching ratios for J / psi --> gamma pi0, gamma eta, gamma eta' --> 3gamma on the BES
7471018
A side-by-side comparison of Daya Bay antineutrino detectors
The Daya Bay Reactor Neutrino Experiment is designed to determine precisely the neutrino mixing angle θ_(13) with a sensitivity better than 0.01 in the parameter sin^22θ_(13) at the 90% confidence level. To achieve this goal, the collaboration will build eight functionally identical antineutrino detectors. The first two detectors have been constructed, installed and commissioned in Experimental Hall 1, with steady data-taking beginning September 23, 2011. A comparison of the data collected over the subsequent three months indicates that the detectors are functionally identical, and that detector-related systematic uncertainties are smaller than requirements.
126297547
Experimental study of hadron inclusive production in J / psi energy region
12149444
Observation of a Near-Threshold Enhancement in the p-anti-p Mass Spectrum from Radiative J/psi --> gamma-p-anti-p Decays
We observe a narrow enhancement near 2m{sub p} in the invariant mass spectrum of p{bar p} pairs from radiative J/{psi} {yields} {gamma}p{bar p} decays. No similar structure is seen in J/{psi} {yields} {pi}{sup 0} p{bar p} decays. The results are based on an analysis of a 58 million event sample of J/{psi} decays accumulated with the BESII detector at the Beijing electron-positron collider. The enhancement can be fit with either an S- or P-wave Breit Wigner resonance function. In the case of the S-wave fit, the peak mass is below 2m{sup p} at M = 1859{sub -10}{sup +3} (stat){sub -25}{sup +5} (sys) MeV/c{sup 2} and the total width is {Lambda} < 30 MeV/c{sup 2} at the 90 percent confidence level. These mass and width values are not consistent with the properties of any known particle.
120632182
Direct measurements of the branching fractions for inclusive K± and inclusive semileptonic decays of D+ and D0 mesons
Abstract With singly-tagged D ¯ samples selected from the data collected at and around 3.773 GeV with the BESII detector at the BEPC collider, we have measured the branching fractions for the inclusive K ± decays of D + and D 0 mesons, which are BF ( D + → K − X ) = ( 24.7 ± 1.3 ± 1.2 ) % , BF ( D + → K + X ) = ( 6.1 ± 0.9 ± 0.4 ) % , BF ( D 0 → K − X ) = ( 57.8 ± 1.6 ± 3.2 ) % and BF ( D 0 → K + X ) = ( 3.5 ± 0.7 ± 0.3 ) % , respectively. We have also measured the branching fractions for the inclusive semileptonic decays of D + and D 0 mesons to be BF ( D + → e + X ) = ( 15.2 ± 0.9 ± 0.8 ) % and BF ( D 0 → e + X ) = ( 6.3 ± 0.7 ± 0.4 ) % . These yield the ratio of their partial widths to be Γ ( D + → e + X ) / Γ ( D 0 → e + X ) = 0.95 ± 0.12 ± 0.07 .
125590985
Experimental study of f0(975) in J / psi decays
118458330
A Model Independent Method to Study Dark Matter Induced Leptons and Gamma Rays
By using recent data, we directly determine the dark matter (DM)-induced e± spectrum at the source from experimental measurements at the earth, without reference to specific particle physics models. The DM-induced gamma rays emitted via inverse Compton scattering are then obtained in a model-independent way. However, the results depend on the choice of the astrophysical e± background, which is not reliably known. Nevertheless, we calculate, as an illustration, the fluxes of gamma rays from the Fornax cluster in the decaying DM scenario with various astrophysical e± backgrounds. Without any assumptions on details of the DM model, the predictions turn out to be either in disagreement with or only marginally below the upper limits measured recently by the Fermi-LAT Collaboration. In addition, these DM-induced ICS gamma rays in the GeV range are shown to be almost independent of choices of cosmic ray propagation model and of DM density profile, when a given astrophysical e± background is assumed. This provide...
124189092
Working Group Report: New Particles, Forces, and Dimensions
119285874
Separable and non-separable multi-field inflation and large non-Gaussianity
In this paper we provide a general framework based on $\delta N$ formalism to estimate the cosmological observables pertaining to the cosmic microwave background radiation for non-separable potentials, and for generic \emph{end of inflation} boundary conditions. We provide analytical and numerical solutions to the relevant observables by decomposing the cosmological perturbations along the curvature and the isocurvature directions, \emph{instead of adiabatic and entropy directions}. We then study under what conditions large bi-spectrum and tri-spectrum can be generated through phase transition which ends inflation. In an illustrative example, we show that large $f_{NL}\sim {\cal O}(80)$ and $\tau_{NL}\sim {\cal O}(20000)$ can be obtained for the case of separable and non-separable inflationary potentials.
119257125
Higgs boson decays and production via gluon fusion at LHC in littlest Higgs models with T-parity
We study the Higgs boson decays and production via gluon fusion at the LHC as a probe of two typical littlest Higgs models which introduce a top quark partner with different (even and odd) T parity to cancel the Higgs mass quadratic divergence contributed by the top quark. For each model, we consider two different choices for the down-type quark Yukawa couplings. We first examine the branching ratios of the Higgs boson decays and then study the production via gluon fusion followed by the decay into two photons or two weak gauge bosons. We find that the predictions can be quite different for different models or different choices of down-type quark Yukawa couplings, and all these predictions can sizably deviate from the standard model predictions. So the Higgs boson processes at the LHC can be a sensitive probe for these littlest Higgs models.
119107111
The Goldstino field in linear and nonlinear realizations of supersymmetry
Abstract A Goldstino field in the nonlinear realization of supersymmetry is constructed from an appropriate chiral super-multiplet of the linear theory, in general O'Raifeartaigh-like models. The linear theories can thus be reformulated into their nonlinear versions, via the standard procedure. The Goldstino field disappears totally from the original Lagrangian in the process, but reemerges in the Jacobian of the transformation and covariant derivatives. Vertices with Goldstino fields carry at least one space–time derivative, as one would have expected.