11 research outputs found
Scaling and Duality in Semi-exclusive Processes
We discuss extending scaling and duality studies to semi-exclusive processes.
We show that semi-exclusive hard pion photoproduction should exhibit scaling
behavior in kinematic regions where the photon and pion both interact directly
with the same quark. We show that such kinematic regions exist. We also show
that the constancy with changing momentum transfer of the resonance
peak/scaling curve ratio, familiar for many resonances in deep inelastic
scattering, is also expected in the semi-exclusive case.Comment: 8 pages, 4 figures, submitted to Phys.Rev.
Flavor from Strongly Coupled Supersymmetry
Strongly coupled supersymmetric theories can give rise to composite quarks
and leptons at low energy. We show that the internal structure of these
particles can explain the origin of three generations and provide a qualitative
understanding of mass ratios and mixing angles between the different flavors of
fermions, all within a renormalizable theory. The main point of the paper is to
show how fermion masses and mixing angles can result from a ``dual''
Frogatt-Nielsen mechanism: fields neutral under which carry flavor quantum numbers are confined within quarks and
leptons, and from their perturbative interactions arises the observed flavor
structure.Comment: 28 pages, 5 figures, LATEX. A few typos corrected and references
adde
Hadron Spectrum in QCD with Valence Wilson Fermions and Dynamical Staggered Fermions at $6/g^2=5.6
We present an analysis of hadronic spectroscopy for Wilson valence quarks
with dynamical staggered fermions at lattice coupling at
sea quark mass and 0.025, and of Wilson valence quarks in quenched
approximation at and 5.95, both on lattices. We
make comparisons with our previous results with dynamical staggered fermions at
the same parameter values but on lattices doubled in the temporal
direction.Comment: 32 page
Simple quark model with chiral phenomenology
We propose a new approach to the determination of hadronic observables in which the essential features of chiral symmetry are combined with conventional constituent quark models. To illustrate the approach, we consider the simple quark model in the limit of SU~3! flavor symmetry at the strange quark mass. The comparison with data is made after an analytic continuation which ensures the correct leading nonanalytic behavior of chiral perturbation theory. The approach not only gives an excellent fit for the octet baryon magnetic moments but the prediction for the D11 magnetic moment is also in good agreement with current measurements.I. C. Cloet, D. B. Leinweber, and A. W. Thoma
Baryon Spectroscopy in Lattice QCD
We review recent developments in the study of excited baryon spectroscopy in
lattice QCD. After introducing the basic methods used to extract masses from
correlation functions, we discuss various interpolating fields and lattice
actions commonly used in the literature. We present a survey of results of
recent calculations of excited baryons in quenched QCD, and outline possible
future directions in the study of baryon spectra.Comment: Contribution to Lecture Notes in Physics on Lattice Hadron Physics,
43 pages, 11 figures, 3 table
XSEN: a νN Cross Section Measurement using High Energy Neutrinos from pp collisions at the LHC
XSEN (Cross Section of Energetic Neutrinos) is a small experiment designed to study, for the first time, neutrino-nucleon interactions (including the tau flavour) in the 0.5-1 TeV neutrino energy range. The detector will be installed in the decommissioned TI18 tunnel and uses nuclear emulsions. Its simplicity allows construction and installation before the LHC Run 3, 2021-2023; with 150/fb in Run3, the experiment can record up to two thousand neutrino interactions, and up to a hundred tau neutrino events. The XSEN detector intercepts the intense neutrino flux, generated by the LHC beams colliding in IP1, at large pseudo-rapidities, where neutrino energies can exceed the TeV. Since the neutrino-N interaction cross section grows almost linearly with energy, the detector can be light and still collect a considerable sample of neutrino interactions. In our proposal, the detector weighs less than 3 tons. It is lying slightly above the ideal prolongation of the LHC beam from the straight section; this configuration, off the beam axis, although very close to it, enhances the contribution of neutrinos from c and b decays, and consequently of tau neutrinos. The detector fits in the TI18 tunnel without modifications. We plan for a demonstrator experiment in 2021 with a small detector of about 0.5 tons; with 25/fb, nearly a hundred interactions of neutrinos of about 1 TeV can be recorded. The aim of this pilot run is a good in-situ characterisation of the machine-generated backgrounds, an experimental verification of the systematic uncertainties and efficiencies, and a tuning of the emulsion analysis infrastructure and efficiency. This Letter provides an overview of the experiment motivations, location, design constraints, technology choice, and operation