632 research outputs found

    A study of the f0(1370), f0(1500), f0(2000) and f2(1950) observed in the centrally produced 4pi final states

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    The production and decay properties of the f0(1370), f0(1500), f0(2000) and f2(1950) have been studied in central pp interactions at 450 GeV/c. The dPT, phi and |t| distributions of these resonances are presented. For the J = 0 states, the f0(1370) and f0(2000) have similar dPT and phi dependences. These are different to the dPT and phi dependences of the f0(980), f0(1500) and f0(1710). For the J = 2 states the f2(1950) has different dependences to the f2(1270) and f2'(1520). This shows that the dPT and phi dependences are not just J phenomena.Comment: 14 pages, Latex, 4 Figure

    A coupled channel analysis of the centrally produced K+K- and pi+pi- final states in pp interactions at 450 GeV/c

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    A coupled channel analysis of the centrally produced K+K- and pi+pi- final states has been performed in pp collisions at an incident beam momentum of 450 GeV/c. The pole positions and branching ratios to pipi and KK of the f0(980), f0(1370), f0(1500) and f0(1710) have been determined. A systematic study of the production properties of all the resonances observed in the pi+pi- and K+K- channels has been performed.Comment: 16 pages, Latex, 5 Figure

    Experimental evidence for a vector-like behaviour of Pomeron exchange

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    Evidence is presented that the Pomeron act as a non-conserved vector current. A study has been made of the azimuthal angle phi, which is defined as the angle between the pT vectors of the two outgoing protons, in the reaction pp -> pp(X0) for those resonances (X0) which are compatible with being produced by double Pomeron exchange. These distributions have been compared with a model which describes the Pomeron as a non-conserved vector current and a qualitative agreement is found. In addition, when one of the particles exchanged is known to have spin 0, namely pi-Pomeron exchange, the phi distribution is flat.Comment: 13 pages, Latex, 4 Figure

    General Spectral Flow Formula for Fixed Maximal Domain

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    We consider a continuous curve of linear elliptic formally self-adjoint differential operators of first order with smooth coefficients over a compact Riemannian manifold with boundary together with a continuous curve of global elliptic boundary value problems. We express the spectral flow of the resulting continuous family of (unbounded) self-adjoint Fredholm operators in terms of the Maslov index of two related curves of Lagrangian spaces. One curve is given by the varying domains, the other by the Cauchy data spaces. We provide rigorous definitions of the underlying concepts of spectral theory and symplectic analysis and give a full (and surprisingly short) proof of our General Spectral Flow Formula for the case of fixed maximal domain. As a side result, we establish local stability of weak inner unique continuation property (UCP) and explain its role for parameter dependent spectral theory.Comment: 22 page

    A study of the etapipi channel produced in central pp interactions at 450 GeV/c

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    The reaction pp -> pf (eta pi pi) ps has been studied at 450 GeV/c. There is clear evidence for an a2(1320)pi decay mode of the eta2(1645) and eta2(1870). In addition, there is evidence for an a0(980)pi$ decay mode of both resonances and an f2(1270)eta decay mode of the eta2(1870). No evidence is found for a JPC = 2++ a2(1320)pi wave.Comment: 15 pages, Latex, 4 Figures Branching ratio a2pi /f2 eta correcte

    On the Quantum Invariant for the Spherical Seifert Manifold

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    We study the Witten--Reshetikhin--Turaev SU(2) invariant for the Seifert manifold S3/ΓS^3/\Gamma where Γ\Gamma is a finite subgroup of SU(2). We show that the WRT invariants can be written in terms of the Eichler integral of the modular forms with half-integral weight, and we give an exact asymptotic expansion of the invariants by use of the nearly modular property of the Eichler integral. We further discuss that those modular forms have a direct connection with the polyhedral group by showing that the invariant polynomials of modular forms satisfy the polyhedral equations associated to Γ\Gamma.Comment: 36 page

    Particle Acceleration in Pulsar Wind Nebulae: PIC modelling

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    We discuss the role of particle-in-cell (PIC) simulations in unveiling the origin of the emitting particles in PWNe. After describing the basics of the PIC technique, we summarize its implications for the quiescent and the flaring emission of the Crab Nebula, as a prototype of PWNe. A consensus seems to be emerging that, in addition to the standard scenario of particle acceleration via the Fermi process at the termination shock of the pulsar wind, magnetic reconnection in the wind, at the termination shock and in the Nebula plays a major role in powering the multi-wavelength signatures of PWNe.Comment: 32 pages, 16 figures, to appear in the book "Modelling Nebulae" edited by D. Torres for Springer, based on the invited contributions to the workshop held in Sant Cugat (Barcelona), June 14-17, 201

    An overlooked play? Structure, stratigraphy and hydrocarbon prospectivity of the Carboniferous in the East Irish Sea–North Channel basin complex

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    Seismic mapping of key Paleozoic surfaces in the East Irish Sea–North Channel region has been incorporated into a review of hydrocarbon prospectivity. The major Carboniferous basinal and inversion elements are identified, allowing an assessment of the principal kitchens for hydrocarbon generation and possible migration paths. A Carboniferous tilt-block is identified beneath the central part of the (Permian–Mesozoic) East Irish Sea Basin (EISB), bounded by carbonate platforms to the south and north. The importance of the Bowland Shale Formation as the key source rock is reaffirmed, the Pennine Coal Measures having been extensively excised following Variscan inversion and pre-Permian erosion. Peak generation from the Bowland source coincided with maximum burial of the system in late Jurassic–early Cretaceous time. Multiphase Variscan inversion generated numerous structural traps whose potential remains underexplored. Leakage of hydrocarbons from these into the overlying Triassic Ormskirk Sandstone reservoirs is likely to have occurred on a number of occasions, but currently unknown is how much resource remains in place below the Base Permian Unconformity. Poor permeability in the Pennsylvanian strata beneath the Triassic fields is a significant risk; the same may not be true in the less deeply buried marginal areas of the EISB, where additional potential plays are present in Mississippian carbonate platforms and latest Pennsylvanian clastic sedimentary rocks. Outside the EISB, the North Channel, Solway and Peel basins also contain Devonian and/or Carboniferous rocks. There have, however, been no discoveries, largely a consequence of the absence of a high-quality source rock and a regional seal comparable to the Mercia Mudstone Group and Permian evaporites of the Cumbrian Coast Group in the EISB
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