373 research outputs found

    Upsilon Production In pp Collisions For Forward Rapidities At LHC

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    This is a continuation of recent studies of Υ(nS)\Upsilon(nS) production at the LHC in pp collisions. Our previous studies were for rapidity y=-1 to 1 for the CMS detector, while the present study is for y=2.5 to 4.0 at the LHC.Comment: 5 pages, 2 figure

    Reduced Aspect Ratio HELIAS Configurations

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    Estimate of CP Violation for the LBNE Project and $\delta_{CP}

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    Measurements of CP violation (CPV) and the basic δCP\delta_{CP} parameter are the goals of the LBNE Project, which is being planned. Using the expected energy and baseline parameters for the LBNE Project, CPV and the dependence of CPV on δCP\delta_{CP} are estimated, to help in the planning of this project.Comment: 7 pages, 1 figur

    The electromagnetic effects in isospin symmetry breakings of q{\bar q} systems

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    The isospin symmetry breakings of q{\bar q} are investigated in the QCD sum rule method. The electromagnetic effects are evaluated following the procedure requiring that the electromagnetic effects for charged meson be gauge invariant. We find that the electromagnetic effects are also dominant in the isospin violations of rho meson, which have been shown to be the case in the mass splittings of pions. The numerical results for the difference of pion decay constants and the masses of rho mesons are presented, which are consistent with the data.Comment: To appear in Phys. Rev. D (1997

    Determining 1−−1^{--} Heavy Hybrid Masses via QCD Sum Rules

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    The masses of 1−−1^{--} charmonium and bottomonium hybrids are evaluated in terms of QCD sum rules. We find that the ground state hybrid in charm sector lies in mHc=4.12∼4.79m_{H_c}=4.12\sim 4.79 GeV, while in bottom sector the hybrid may situated in mHb=10.24∼11.15m_{H_b} = 10.24\sim 11.15 GeV. Since the numerical result on charmonium hybrid mass is not compatible with the charmonium spectra, including structures newly observed in experiment, we tempt to conclude that such a hybrid does not purely exist, but rather as an admixture with other states, like glueball and regular quarkonium, in experimental observation. However, our result on bottomonium hybrid coincide with the "exotic structure" recently observed at BELLE.Comment: 15 pages, 5 figures, version to appear in J.Phys.

    Quark propagator, instantons and gluon propagator

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    The Schwinger-Dyson formalism is used to check the consistency of instanton model solutions for the quark propagator with recent models of confining gluon propagators. We find that the models are not consistent. A major discrepancy is the absence of a vector condensate in the instanton model that is present in the solutions with nonperturbative confining gluons.Comment: Latex file, no figure

    Constructing Hybrid Baryons with Flux Tubes

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    Hybrid baryon states are described in quark potential models as having explicit excitation of the gluon degrees of freedom. Such states are described in a model motivated by the strong coupling limit of Hamiltonian lattice gauge theory, where three flux tubes meeting at a junction play the role of the glue. The adiabatic approximation for the quark motion is used, and the flux tubes and junction are modeled by beads which are attracted to each other and the quarks by a linear potential, and vibrate in various string modes. Quantum numbers and estimates of the energies of the lightest hybrid baryons are provided.Comment: 4 pages, RevTeX. Submitted to Physical Review Letter

    A model for the distribution of aftershock waiting times

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    In this work the distribution of inter-occurrence times between earthquakes in aftershock sequences is analyzed and a model based on a non-homogeneous Poisson (NHP) process is proposed to quantify the observed scaling. In this model the generalized Omori's law for the decay of aftershocks is used as a time-dependent rate in the NHP process. The analytically derived distribution of inter-occurrence times is applied to several major aftershock sequences in California to confirm the validity of the proposed hypothesis.Comment: 4 pages, 3 figure
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