22 research outputs found

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

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    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

    Transplant resources for Triticeae genomic data.

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    © Crop Science Society of America. The genome sequences of many important Triticeae species, including bread wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.), remained uncharacterized for a long time because their high repeat content, large sizes, and polyploidy. As a result of improvements in sequencing technologies and novel analyses strategies, several of these have recently been deciphered. These efforts have generated new insights into Triticeae biology and genome organization and have important implications for downstream usage by breeders, experimental biologists, and comparative genomicists. transPLANT (http://www.transplantdb.eu) is an EU-funded project aimed at constructing hardware, software, and data infrastructure for genome-scale research in the life sciences. Since the Triticeae data are intrinsically complex, heterogenous, and distributed, the transPLANT consortium has undertaken efforts to develop common data formats and tools that enable the exchange and integration of data from distributed resources. Here we present an overview of the individual Triticeae genome resources hosted by transPLANT partners, introduce the objectives of transPLANT, and outline common developments and interfaces supporting integrated data access

    TransPLANT resources for triticeae genomic data

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    The genome sequences of many important Triticeae species, including bread wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.), remained uncharacterized for a long time because their high repeat content, large sizes, and polyploidy. As a result of improvements in sequencing technologies and novel analyses strategies, several of these have recently been deciphered. These efforts have generated new insights into Triticeae biology and genome organization and have important implications for downstream usage by breeders, experimental biologists, and comparative genomicists. transPLANT (http://www.transplantdb.eu) is an EU-funded project aimed at constructing hardware, software, and data infrastructure for genome-scale research in the life sciences. Since the Triticeae data are intrinsically complex, heterogenous, and distributed, the transPLANT consortium has undertaken efforts to develop common data formats and tools that enable the exchange and integration of data from distributed resources. Here we present an overview of the individual Triticeae genome resources hosted by transPLANT partners, introduce the objectives of transPLANT, and outline common developments and interfaces supporting integrated data access

    Final COMPASS results on the deuteron spin-dependent structure function g(1)(d) and the Bjorken sum rule

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    Final results are presented from the inclusive measurement of deep-inelastic polarised-muon scattering on longitudinally polarised deuterons using a 6LiD target. The data were taken at 160 GeV beam energy and the results are shown for the kinematic range 1 (GeV/c)2 < Q2 < 100 (GeV/c)2 in photon virtuality, 0.004 < x < 0.7 in the Bjorken scaling variable and W > 4GeV/c2 in the mass of the hadronic final state. The deuteron double-spin asymmetry A(1)(d) and the deuteron longitudinal-spin structure function g(1)(d) are presented in bins of x and Q2. Towards lowest accessible values of x, g(1)(d) decreases and becomes consistent with zero within uncertainties. The presented final g(1)(p) values together with the recently published final g(1)(p) values of COMPASS are used to again evaluate the Bjorken sum rule and perform the QCD fit to the g1 world data at next-to-leading order of the strong coupling constant. In both cases, changes in central values of the resulting numbers are well within statistical uncertainties. The flavour singlet axial charge a0, which is identified in the MS renormalisation scheme with the total contribution of quark helicities to the nucleon spin, is extracted at next-to-leading order accuracy from only the COMPASS deuteron data: a0(Q2 = 3 (GeV/c)2) = 0.32 +/- 0.02stat +/- 0.04syst +/- 0.05evol. Together with the recent results on the proton spin structure function g(1)(p), the results on g(1)(d) constitute the COMPASS legacy on the measurements of g1 through inclusive spin-dependent deep inelastic scattering

    Measurement of the Cross Section for High-pTp_T Hadron Production in Scattering of 160 GeV/c Muons off Nucleons

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    The cross section for production of charged hadrons with high transverse momenta in scattering of 160 GeV/c muons off nucleons at low photon virtualities has been measured at the COMPASS experiment at CERN. The results, which cover transverse momenta from 1.1 to 3.6 GeV/c, are compared to a next-to-leading order perturbative Quantum Chromodynamics (NLO pQCD) calculation in order to evaluate the applicability of pQCD to this process in the kinematic domain of the experiment. The shape of the calculated differential cross section as a function of transverse momentum is found to be in good agreement with the experimental data, but the normalization is underestimated by NLO pQCD. This discrepancy may point towards the relevance of terms beyond NLO in the pQCD framework. The dependence of the cross section on the pseudo-rapidity and on the charge of the hadrons is also discussed

    Odd and even partial waves of ηπ\eta\pi^- and ηπ\eta'\pi^- in πpη()πp\pi^-p\to\eta^{(\prime)}\pi^-p at 191GeV/c191\,\textrm{GeV}/c

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