Observation of a J^PC = 1-+ exotic resonance in diffractive dissociation of 190 GeV/c pi- into pi- pi- pi+

The COMPASS experiment at the CERN SPS has studied the diffractive dissociation of negative pions into the pi- pi- pi+ final state using a 190 GeV/c pion beam hitting a lead target. A partial wave analysis has been performed on a sample of 420000 events taken at values of the squared 4-momentum transfer t' between 0.1 and 1 GeV^2/c^2. The well-known resonances a1(1260), a2(1320), and pi2(1670) are clearly observed. In addition, the data show a significant natural parity exchange production of a resonance with spin-exotic quantum numbers J^PC = 1-+ at 1.66 GeV/c^2 decaying to rho pi. The resonant nature of this wave is evident from the mass-dependent phase differences to the J^PC = 2-+ and 1++ waves. From a mass-dependent fit a resonance mass of 1660 +- 10+0-64 MeV/c^2 and a width of 269+-21+42-64 MeV/c^2 is deduced.Comment: 7 page, 3 figures; version 2 gives some more details, data unchanged; version 3 updated authors, text shortened, data unchange

Interface diffusion and amorphous intergranular layers in nanocrystalline Fe90Zr7B3

Herth S, Eggersmann M, Eversheim PD, Wurschum R. Interface diffusion and amorphous intergranular layers in nanocrystalline Fe90Zr7B3. Journal of Applied Physics. 2004;95(9):5075-5080.Iron tracer diffusion was studied in soft-magnetic nanocrystalline Fe90Zr7B3 without any influence of porosity, relaxation, or grain growth. The interfacial diffusion characteristics differ substantially from grain boundaries in metals due to the presence of an intergranular amorphous phase. The reduced diffusivity in thin amorphous layers compared to in the initial amorphous phase indicates the effect of confinement. The indication of a second, fast interfacial diffusion path is found and quantitatively analyzed within the framework of a two interface-type model. (C) 2004 American Institute of Physics

Alpha-decay half-life of 253Es in metallic Fe at temperatures between 4 K and 50 mK

It has been claimed recently that half-lives of radioactive nuclei embedded in metals would be significantly affected by electron screening provided by the metal. The effectwould further be strengthened at low temperatures. We have determined the half-life-of 253Es nuclei embedded in iron at temperatures between 4 K and 50 mK. Our results agree with the room temperature literature value within about 2% and show no dependence on temperature over a range of almost two orders of magnitude.status: publishe

X-ray Reflectivity Studies of the Surface Structure of Liquid Metals

Extensive theoretical predictions of atomic layering at the surfaces of liquid metals have remained unconfirmed due to the limited range of wave vector transfer qz that has been previously measured. We report here on X-ray reflectivity studies from the surfaces of liquid mercury to qz greater-than or equivalent to 2.8 Å−1, and gallium to qz greater-than or equivalent to 3.0 Å−1, that show peaks which clearly demonstrate atomic layering with spacing on the order of the atomic diameter. The exponential decay of layer penetration into the bulk for Ga (6.5 Å) is larger than for Hg (3–3.5 Å). The prominent features of the layering remain unchanged under self-assembled monolayers of thiols. The Ga layering shows an unexpected strong temperature dependence. Differences between the reflectivity from Ga and Hg at small qz indicate fundamental differences in the surface structure for these two liquid metals.Engineering and Applied Science

Hadron transverse momentum distributions in muon deep inelastic scattering at 160 GeV/c

Multiplicities of charged hadrons produced in deep inelastic muon scattering off a LiD target have been measured as a function of the DIS variables x , Q , W and the final state hadron variables p and z. The p distributions are fitted with a single exponential function at low values of p to determine the dependence of 〈p 〉 on x , Q , W and z. The z-dependence of 〈p 〉 is shown to be a potential tool to extract the average intrinsic transverse momentum squared of partons, 〈k 〉, as a function of x and Q in a leading order QCD parton model. 6 2 2 2 2 2 2 2 2 2 2 Bj T T T T Bj T ⊥ B

Hadron transverse momentum distributions in muon deep inelastic scattering at 160 GeV/c

Multiplicities of charged hadrons produced in deep inelastic muon scattering off a 6LiD target have been measured as a function of the DIS variables xBj , Q2, W2 and the final state hadron variables pT and z. The p2T distributions are fitted with a single exponential function at low values of p2T to determine the dependence of 〈p2T 〉 on xBj , Q2, W2 and z. The z-dependence of 〈p2T 〉 is shown to be a potential tool to extract the average intrinsic transverse momentum squared of partons, 〈k2⊥〉, as a function of xBj and Q2 in a leading order QCD parton model

Epidemiological applications of long-term stress in daily life.

The gluon polarisation in the nucleon has been determined by detecting charm production via D0 meson decay to charged K and \u3c0 in polarised muon scattering off a longitudinally polarised deuteron target. The data were taken by the COMPASS Collaboration at CERN between 2002 and 2006 and correspond to an integrated luminosity of 2.8 fb 121. The dominant underlying process of charm production is the photon\u2013gluon fusion to a_(c barc) pair. A leading order QCD approach gives an average gluon polarisation of _x= 120.49\ub10.27(stat)\ub10.11(syst) at a scale \u3bc^2 4813 (GeV/c)^2 and at an average gluon momentum fraction 480.11. The longitudinal cross-section asymmetry for D0 production is presented in bins of the transverse momentum and the energy of the D0 meson