[en] We generalize the leading twist theory of nuclear shadowing and calculate quark and gluon generalized parton distributions (GPDs) of spinless nuclei. We predict very large nuclear shadowing for nuclear GPDs. In the limit of the purely transverse momentum transfer, our nuclear GPDs become impact parameter dependent nuclear parton distributions (PDFs). Nuclear shadowing induces non-trivial correlations between the impact parameter b$ and the light-cone fraction x$. We make predictions for the deeply virtual Compton scattering (DVCS) amplitude and the DVCS cross section on ²⁰⁸Pb at high energies. We calculate the cross section of the Bethe-Heitler (BH) process and address the issue of the extraction of the DVCS signal from the e A → e γ A cross section. We find that the e A → e γ A differential cross section is dominated by DVCS at the momentum transfer t$ near the minima of the nuclear form factor. We also find that nuclear shadowing leads

[en] In this article, we take the D_s_3"∗(2860) and D_s_1"∗(2860) as the 1"3D_3 and 1"3D_1cs"-"b"a"r states, respectively, and we study their strong decays with the heavy meson effective theory by including the chiral symmetry-breaking corrections. We can reproduce the experimental data Br(D_s_J"∗(2860))(→D"∗K)/Br(D_s_J"∗(2860)→DK)=1.10±0.15±0.19 with suitable hadronic coupling constants; the assignment of the D_s_J"∗(2860) as the D_s_3"∗(2860) is favored, the chiral symmetry-breaking corrections are large. Furthermore, we obtain the analytical expressions of the decay widths, which can be confronted with the experimental data in the future to fit the unknown coupling constants. The predictions of the ratios among the decay widths can be used to study the decay properties of the D_s_3"∗(2860) and D_s_1"∗(2860) so as to identify them unambiguously. On the other hand, if the chiral symmetry-breaking corrections are small, the large ratio R=1.10±0.15±0.19 requires that the D_s_J"∗(2860) consists of at least the four resonances, D_s_1"∗(2860), D_s_2"∗(2860), D_s_2"∗"′(2860), D_s_3"∗(2860)

[en] The GERmanium Detector Array (Gerda) at the Gran Sasso Underground Laboratory (LNGS) searches for the neutrinoless double beta decay (0νββ) of "7"6Ge. Germanium detectors made of material with an enriched "7"6Ge fraction act simultaneously as sources and detectors for this decay. During Phase I of theexperiment mainly refurbished semi-coaxial Ge detectors from former experiments were used. For the upcoming Phase II, 30 new "7"6Ge enriched detectors of broad energy germanium (BEGe)-type were produced. A subgroup of these detectors has already been deployed in Gerda during Phase I. The present paper reviews the complete production chain of these BEGe detectors including isotopic enrichment, purification, crystal growth and diode production. The efforts in optimizing the mass yield and in minimizing the exposure of the "7"6Ge enriched germanium to cosmic radiation during processing are described. Furthermore, characterization measurements in vacuum cryostats of the first subgroup of seven BEGe detectors and their long-term behavior in liquid argon are discussed. The detector performance fulfills the requirements needed for the physics goals of Gerda Phase II

[en] We propose a model based on the SU(3)_C⊗SU(3)_L⊗U(1)_X gauge symmetry with an extra S_3⊗Z_2⊗Z_4⊗Z_1_2 discrete group, which successfully accounts for the SM quark mass and mixing pattern. The observed hierarchy of the SM quark masses and quark mixing matrix elements arises from the Z_4 and Z_1_2 symmetries, which are broken at a very high scale by the SU(3)_L scalar singlets (σ,ζ) and τ, charged under these symmetries, respectively. The Cabbibo mixing arises from the down-type quark sector whereas the up quark sector generates the remaining quark mixing angles. The obtained magnitudes of the CKM matrix elements, the CP violating phase, and the Jarlskog invariant are in agreement with the experimental data

[en] A search for the production of single-top-quarks in association with missing energy is performed in proton–proton collisions at a centre-of-mass energy of √s=8 TeV with the ATLAS experiment at the large hadron collider using data collected in 2012, corresponding to an integrated luminosity of 20.3 fb"-"1. In this search, the W boson from the top quark is required to decay into an electron or a muon and a neutrino. No deviation from the standard model prediction is observed, and upper limits are set on the production cross-section for resonant and non-resonant production of an invisible exotic state in association with a right-handed top quark. In the case of resonant production, for a spin-0 resonance with a mass of 500 GeV, an effective coupling strength above 0.15 is excluded at 95 % confidence level for the top quark and an invisible spin-1/2 state with mass between 0 and 100 GeV. In the case of non-resonant production, an effective coupling strength above 0.2 is excluded at 95 % confidence level for the top quark and an invisible spin-1 state with mass between 0 and 657 GeV

[en] We calculate the cross section for the inclusive production of B mesons in pp and pp_-_b_a_r collisions at next-to-leading order in the general-mass variable-flavor-number scheme and show that a suitable choice of factorization scales leads to a smooth transition to the fixed-flavor-number scheme. Our numerical results are in good agreement with data from the Tevatron and LHC experiments at small and at large transverse momenta

[en] Measurements of the differential and double-differential Drell–Yan cross sections in the dielectron and dimuon channels are presented. They are based on proton–proton collision data at √s=8 TeV recorded with the CMS detector at the LHC and corresponding to an integrated luminosity of 19.7 fb"-"1. The measured inclusive cross section in the Z peak region (60–120 GeV), obtained from the combination of the dielectron and dimuon channels, is 1138±8 (exp)±25 (theo)±30 (lumi)/,pb, where the statistical uncertainty is negligible. The differential cross section dσ/dm in the dilepton mass range 15–2000 GeV is measured and corrected to the full phase space. The double-differential cross section d"2σ/dm d|y| is also measured over the mass range 20 to 1500 GeV and absolute dilepton rapidity from 0 to 2.4. In addition, the ratios of the normalized differential cross sections measured at √s=7 and 8 TeV are presented. These measurements are compared to the predictions of perturbative QCD at next-to-leading and next-to-next-to-leading (NNLO) orders using various sets of parton distribution functions (PDFs). The results agree with the NNLO theoretical predictions computed with fewz 3.1 using the CT10 NNLO and NNPDF2.1 NNLO PDFs. The measured double-differential cross section and ratio of normalized differential cross sections are sufficiently precise to constrain the proton PDFs

[en] A contribution to J/ψ hadroproduction is analyzed in which the meson production is mediated by three-gluon partonic state, with two gluons coming from the target and one gluon from the projectile. This mechanism involves double gluon density in one of the protons, hence this contribution enters at a non-leading twist. It is, however, relevant due to an enhancement factor coming from large double gluon density at small x. We calculate the three-gluon contribution to J/ψ hadroproduction within perturbative QCD in the k_T-factorization framework. Results are obtained for differential p_T-dependent cross sections for all J/ψ polarizations and for the sum over the polarization components. The rescattering contribution is found to provide a significant correction to the standard leading twist cross section at the energies of the Tevatron or the LHC at moderate p_T. We suggest J/ψ production in proton–nucleus collision as a possible probe of the triple-gluon mechanism

[en] In this article, we calculate the form factors and the coupling constant of the vertex D_s"∗D_sϕ using the three-point QCD sum rules. We consider the contributions of the vacuum condensates up to dimension 7 in the operator product expansion. And all possible off-shell cases are considered, ϕ, D_s and D_s"∗, resulting in three different form factors. Then we fit the form factors into analytical functions and extrapolate them into time-like regions, which giving the coupling constant for the process. Our analysis indicates that the coupling constant for this vertex is G_D__s_"∗_D__s_ϕ=4.12±0.70 GeV"-"1. The results of this work are very useful in the other phenomenological analysis. As an application, we calculate the coupling constant for the decay channel D_s"∗→D_sγ and analyze the width of this decay with the assumption of the vector meson dominance of the intermediate ϕ(1020). Our final result about the decay width of this decay channel is Γ=0.59±0.15 keV

[en] We study static black hole solutions in Einstein and Einstein–Gauss–Bonnet gravity with the topology of the product of two spheres, S"n×S"n, in higher dimensions. There is an unusual new feature of the Gauss–Bonnet black hole: the avoidance of a non-central naked singularity prescribes a mass range for the black hole in terms of Λ>0. For an Einstein–Gauss–Bonnet black hole a limited window of negative values for Λ is also permitted. This topology encompasses black strings, branes, and generalized Nariai metrics. We also give new solutions with the product of two spheres of constant curvature