11,517 research outputs found
Double vector meson production in interactions at hadronic colliders
In this paper we revisit the double vector meson production in interactions at heavy ion collisions and present, by the first time,
predictions for the and production in proton --
nucleus and proton -- proton collisions. In order to obtain realistic
predictions for rapidity distributions and total cross sections for the double
vector production in ultra peripheral hadronic collisions we take into account
of the description of cross section at low
energies as well as its behaviour at large energies, associated to the gluonic
interaction between the color dipoles. Our results demonstrate that the double
production is dominated by the low energy behaviour of the cross section. In contrast, for the double
production, the contribution associated to the description of the QCD dynamics
at high energies contributes significantly, mainly in collisions.
Predictions for the RHIC, LHC, FCC and CEPC - SPPC energies are shown.Comment: 9 pages, 5 figures, 2 tables. arXiv admin note: text overlap with
arXiv:1504.0441
Exclusive photoproduction in hadronic collisions at CERN LHC energies
The exclusive photoproduction in proton-proton and proton -
nucleus collisions at LHC energies is investigated using the color dipole
formalism and considering different models for the wave function and
forward dipole - target scattering amplitude. Our goal is to update the color
dipole predictions and estimate the theoretical uncertainty present in these
predictions. We present predictions for the kinematical ranges probed by the
ALICE, CMS and LHCb Collaborations.Comment: 8 pages, 5 figures and 3 tables. Version to be published in Physics
Letters
Double vector meson production in photon - hadron interactions at hadronic colliders
In this paper we analyse the double vector meson production in photon --
hadron () interactions at collisions and present
predictions for the , and production
considering the double scattering mechanism. We estimate the total cross
sections and rapidity distributions at LHC energies and compare our results
with the predictions for the double vector meson production in
interactions at hadronic colliders. We present predictions for the different
rapidity ranges probed by the ALICE, ATLAS, CMS and LHCb Collaborations. Our
results demonstrate that the and production in
collisions is dominated by the double scattering mechanism, while the
two - photon mechanism dominates in collisions. Moreover, our results
indicate that the analysis of the production at LHC can be useful
to constrain the double scattering mechanism.Comment: 9 pages, 5 figures, 2 tables. Revised and enlarged version to be
published in the European Physical Journal
Double vector meson production in the International Linear Collider
In this paper we study double vector meson production in
interactions at high energies and, using the color dipole picture, estimate the
main observables which can be probed at the International Linear Collider
(ILC). The total
cross-sections for , , and are computed
and the energy and virtuality dependencies are studied in detail. Our results
demonstrate that the experimental analysis of this process is feasible at the
ILC and it can be useful to constrain the QCD dynamics at high energies.Comment: 11 pages, 8 figure
Jamming transition in a two-dimensional open granular pile with rolling resistance
We present a molecular dynamics study of the jamming/unjamming transition in
two-dimensional granular piles with open boundaries. The grains are modeled by
viscoelastic forces, Coulomb friction and resistance to rolling. Two models for
the rolling resistance interaction were assessed: one considers a constant
rolling friction coefficient, and the other one a strain dependent coefficient.
The piles are grown on a finite size substrate and subsequently discharged
through an orifice opened at the center of the substrate. Varying the orifice
width and taking the final height of the pile after the discharge as the order
parameter, one can devise a transition from a jammed regime (when the grain
flux is always clogged by an arch) to a catastrophic regime, in which the pile
is completely destroyed by an avalanche as large as the system size. A finite
size analysis shows that there is a finite orifice width associated with the
threshold for the unjamming transition, no matter the model used for the
microscopic interactions. As expected, the value of this threshold width
increases when rolling resistance is considered, and it depends on the model
used for the rolling friction.Comment: 9 pages, 6 figure
Produtividade de forragem de gramíneas e leguminosas em pastagens puras e consorciadas no Acre.
A formação de ecossistemas homogêneos de pastagens cultivadas na Amazônia, com a predominância de uma espécie de gramínea forrageira, tem favorecido a ocorrência de pragas e doenças que afetam a produtividade e a sustentabilidade dos sistemas de produção pecuários tradicionais. Este estudo teve o objetivo de avaliar a produtividade e a taxa de acúmulo de forragem de gramíneas e leguminosas em pastagens formadas com as gramíneas Panicum maximum cv. Colonião, Tobiatã, Massai e BRA-006670 e as leguminosas amnedoim forrageiro (Arachis pintoiu BRA-031143 e Arachis glabrata cv. Arbrook) e puerária (Pueraria phaseoloides) em estandes puros e consorciados.bitstream/item/76387/1/CPAF-AC-BOL.-PESQ.-33-01.pd
Exclusive vector meson production with a leading neutron in photon - hadron interactions at hadronic colliders
In this paper we study leading neutron production in photon - hadron
interactions which take place in and collisions at large impact
parameters. Using a model that describes the recent leading neutron data at
HERA, we consider exclusive vector meson production in association with a
leading neutron in collisions at RHIC and LHC energies. The total cross
sections and rapidity distributions of , and produced
together with a leading neutron are computed. Our results indicate that the
study of these processes is feasible and that it can be used to improve the
understanding of leading neutron processes and of exclusive vector meson
production.Comment: 8 pages, 3 figures, 2 table
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