19,734 research outputs found
Looking at the photoproduction of massive gauge bosons at the LHeC
In this contribution we report on the investigation of the photoproduction of
W and Z bosons in the planned electron-proton/nucleus collider, the LHeC. The
production cross sections and the number of events are provided and theoretical
uncertainties are discussed. We also analyze the sensitivity of the LHeC
experiment to physics beyond Standard Model by studying the role played by
anomalous WWgamma coupling in the presented process.Comment: Contribution to the proceedings of the XXI International Workshop on
Deep-Inelastic Scattering and Related Subjects (DIS2013), Marseille, 22-26
April 201
Quarkonium plus prompt-photon associated hadroproduction and nuclear shadowing
The quarkonium hadroproduction in association with a photon at high energies
provides a probe of the dynamics of the strong interactions as it is dependent
on the nuclear gluon distribution. Therefore, it could be used to constrain the
behavior of the nuclear gluon distribution in proton-nucleus and
nucleus-nucleus collisions. Such processes are useful to single out the
magnitude of the shadowing/antishadowing effects in the nuclear parton
densities. In this work we investigate the influence of nuclear effects in the
production of JPsi + photon and Upsilon + photon and estimate the transverse
momentum dependence of the nuclear modification factors. The theoretical
framework considered in the JPsi (Upsilon) production associated with a direct
photon at the hadron collider is the non-relativistic QCD (NRQCD) factorization
formalism.Comment: 8 pages, 4 figures. Final version to be published in European
Physical Journal
Inclusive and exclusive dilepton photoproduction at high energies
In this work we investigate the inclusive and exclusive photoproduction of
dileptons, which is relevant for the physics programme to be studied in the
proposed electron-proton collider, the LHeC. In the inclusive case, the process
is sensitive to the parton distribution functions in the photon whereas the
exclusive channel is connected to the small- QCD dynamics. For the latter,
we investigate the role played by saturation physics at a very high energy
scenario. The estimates for production cross sections and the number of events
are presented.Comment: 5 pages, version to be published in Physical Review
Reconstruction of the Cosmic Equation of State for High Redshift
We investigate the possibilities of reconstructing the cosmic equation of
state (EoS) for high redshift. In order to obtain general results, we use two
model-independent approaches. The first reconstructs the EoS using comoving
distance and the second makes use of the Hubble parameter data. To implement
the first method, we use a recent set of Gamma-Ray Bursts (GRBs) measures. To
implement the second method, we generate simulated data using the Sandage-Loeb
() effect; for the fiducial model, we use the model. In both
cases, the statistical analysis is conducted through the Gaussian processes
(non-parametric). In general, we demonstrate that this methodology for
reconstructing the EoS using a non-parametric method plus a model-independent
approach works appropriately due to the feasibility of calculation and the ease
of introducing a priori information ( and ). In the near
future, following this methodology with a higher number of high quality data
will help obtain strong restrictions for the EoS.Comment: 9 pages, 5 figure
Quantiles for Counts
This paper studies the estimation of conditional quantiles of counts. Given the discreteness of the data, some smoothness has to be artificially imposed on the problem. The methods currently available to estimate quantiles of count data either assume that the counts result from the discretization of a continuous process, or are based on a smoothed objective function. However, these methods have several drawbacks. We show that it is possible to smooth the data in a way that allows inference to be performed using standard quantile regression techniques. The performance and implementation of the estimator are illustrated by simulations and an application.Asymmetric maximum likelihood, Jittering, Maximum score estimator, Quantile regression, Smoothing.
Performance evaluation methods in the hotel industry
This paper aims to contribute to increasing knowledge of performance evaluation methods used by the hotel industry, analysing whether there is a link between hotel characteristics and evaluation methods used. To achieve this goal we conducted surveys and interviews with financial officers of 275 four and five star hotels located in Portugal. The results support the conclusion that there is a link between hotel characteristics and performance evaluation methods used
Financial assessment of performance in the hotel industry
This paper aims to increase the knowledge on the financial methods of performance assessment used in the hotel industry, and is based on a review of empirical studies already performed. The reviewed articles allow us to conclude that the financial measures have a significant weight in the hotel industry performance assessment, but they should be complemented by other non-financial measures that consider the particularities of this industry, as well as the specific characteristics of hotel service. As this paper’s main limitation we state the reduced number of studies found on the hotel industry, thus suggesting the need for further research on the performance assessment systems effectively used by the sector, as well as the identification of possible contingency variables that justify the use of specific measures in specific hotels
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