42969120
Quark compositeness, new physics, and ultrahigh-energy cosmic-ray double-core gamma -family events.
We find a significant excess of ultrahigh-energy cosmic-ray events at large transverse momenta with respect to the prediction by standard perturbative QCD at E(lab) approximately 10(4)-10(5) TeV, an energy regime beyond the reach of existing colliders but within the range of future hadron colliders. Such a large deviation cannot be accounted for by a compositeness model of quarks with a characteristic energy scale LAMBDA(c) > 1.4 TeV allowed by current collider experiments, pointing towards new physics.
120678530
A Monte Carlo model for diffractive dissociation in hadron-hadron collisions at high energies
We present a Monte Carlo generator for single diffractive dissociation in hadron-hadron collisions at high energies. The generator, which is based on some kinematic consideration and involves the minimum of theoretical hypothesis, reproduces the experimental data. Such a generator is useful to study the phenomenology of diffractive processes and to explore important roles of diffractive processes in cosmic ray interaction and propagation in the atmosphere and in interstellar space.
121407076
RESULTS FROM THE L3+C EXPERIMENT
40623558
High Energy Processes in Clusters of Galaxies and the Origin of Cosmic Rays.
We test the hypothesis of a universal cosmic ray intensity by calculating the secondary electron or positron production in the hadronic interactions of cosmic ray nuclei with intergalactic gas within clusters of galaxies. We find that the spectral characteristics of the radio synchrotron emission by these secondary electrons is not consistent with observations of the Coma cluster. Thus the hypothesis can be ruled out on cluster scales.
121614633
Reexamination of Cosmic-Ray Composition around 1018 eV from Fly's Eye Data
The cosmic-ray composition around 1018 eV is reexamined using the Chou-Yang model for the simulation of air showers and comparing with Fly's Eye data. This model is quite different from models previously used. Using this model leads to the same conclusion that the primary cosmic-ray composition gets lighter in the region from 3 × 1017 eV to 1019 eV. This conclusion of a changing composition is not sensitive to the choice of model because it results from the measured elongation rate being greater than that predicted for a constant composition by any reasonable model that can account for the measured depths of shower maxima at the Fly's Eye threshold energy. That constraint on elongation rate for a constant composition also implies that the increased rate of energy dissipation that appears in hadron-nucleus interactions near 1014 eV may continue up to the region of 1019 eV.
56454701
Nature of 100 TeV Hadronic Interactions in the Forward Region Seen from Muon Data of the L3+C Experiment
Since the primary cosmic ray composition have been directly measured at energies up to 100 TeV, the multi-muon data of L3+C in the corresponding energy region could be used to determine the nature of the hadronic interactions in the forward region at these energies. Monte Carlo simulation of two hadronic interaction models, implemented in two separate air shower generators, are compared with the L3+C data in this paper.
41291678
A dependence of the K factor in the nuclear shadowing region.
The analysis of the QCD correction to the dilepton production on nuclear targets shows that the gluon Compton scattering terms result in an evident dependence of the {ital K} factor on the mass number of nuclear targets and on the gluon shadowing strength in the nuclear shadowing region. A model is constructed for the nuclear dependence of parton densities, and it suggests that if nuclear targets were bombarded by a proton beam with multi-TeV momentum, the QCD correction to their high-mass dilepton production would be expected to be observable. However, the correction mentioned above to the result of the E772 experiment may be negligible.
39230762
Exact identities in the Hubbard model and t-J model.
Exact identities among the nth extended s-wave-pairing amplitudes in the Hubbard model are presented. They provide more constraints on the possible symmetries of the superconducting gap in the Hubbard model than that between the on-site and the first extended s-wave pairings pointed out by Zhang. For the t-J model, we also find an exact identity between the on-site and the first extended s-wave-pairing amplitudes, which is essentially consistent with that in the Hubbard model. Besides the s-wave pairings, we discuss the constraints on the other pairing amplitudes
32045166
Nuclear dilepton production of Drell-Yan process in the constituent quark model.
The high-mass dilepton production on nuclear targets observed by the E772 Collaboration is analyzed by the constituent quark model. We show that the constituent quark model even without the nuclear shadowing improvement agrees better with the existing data on nuclear targets not only in the inelastic-scattering process, but also in the Drell-Yan process. Further, the QCD improvement for the partonic shadowing model is made. It is found that both the {ital Q}{sup 2} dependence of the shadowing strength and the momentum loss due to the annihilation of the shadowed sea quarks evidently depress the distributions of nuclear sea components in the antishadowing region.