13,473 research outputs found
Inclusive hadron and photon production at LHC in dipole momentum space
Using a momentum space model for the dipole scattering amplitude we present
an analysis of the saturation effects at LHC energies, describing the data on
proton-proton and proton-lead collisions. The model is based on the asymptotic
solutions of the Balitsky-Kovchegov equation, being ideal in the saturation
domain where the target wave function has a high occupation number. We also
make predictions for the nuclear modification ratios on charged hadron and
prompt photon production in the forward region, where the high parton density
effects are important.Comment: New section added and typos corrected. To be published in PR
Dynamics of the peel front and the nature of acoustic emission during peeling of an adhesive tape
We investigate the peel front dynamics and acoustic emission of an adhesive
tape within the context of a recent model by including an additional
dissipative energy that mimics bursts of acoustic signals. We find that the
nature of the peeling front can vary from smooth to stuck-peeled configuration
depending on the values of dissipation coefficient, inertia of the roller, mass
of the tape. Interestingly, we find that the distribution of AE bursts shows a
power law statistics with two scaling regimes with increasing pull velocity as
observed in experiments. In this regimes, the stuck-peeled configuration is
similar to the `edge of peeling' reminiscent of a system driven to a critical
state.Comment: Accepted for publication in Phys. Rev. Let
Aspects of the Unitarized Soft Multipomeron Approach in DIS and Diffraction
We study in detail the main features of the unitarized Regge model (CFKS),
recently proposed to describe the small- domain. It takes into account a
two-component description with two types of unitarized contributions: one is
the multiple pomeron exchange contribution, interacting with the large dipole
configurations, and the other one consists of a unitarized dipole cross
section, describing the interaction with the small size dipoles. We analyze the
ratio between soft and hard pieces as a function of the virtuality, and also
compare the resulting dipole cross section to that from the saturation model.
Diffraction dissociation is also considered, showing the scaling violations in
diffractive DIS and estimating the corresponding logarithmic slope.Comment: 14 pages, 5 postscript figures. Version to be published in Eur. Phys.
J.
Unitarity Corrections to the Proton Structure Functions through the Dipole Picture
We study the dipole picture for the description of the deep inelastic
scattering, focusing on the structure functions which are driven directly by
the gluon distribution. One performs estimates using the effective dipole cross
section given by the Glauber-Mueller approach in QCD, which encodes the
corrections due to the unitarity effects associated with the saturation
phenomenon. We also address issues about frame invariance of the calculations
when analysing the observables.Comment: 16 pages, 8 figures. Version to be published in Phys. Rev.
Momentum space saturation model for deep inelastic scattering and single inclusive hadron production
We show how the AGBS model, originally developed for deep inelastic
scattering applied to HERA data on the proton structure function, can also
describe the RHIC data on single inclusive hadron yield for and
collisions through a new simultaneous fit. The single inclusive hadron
production is modeled through the color glass condensate, which uses the
quark(and gluon)--condensate amplitudes in momentum space. The AGBS model is
also a momentum space model based on the asymptotic solutions of the BK
equation, although a different definition of the Fourier transform is used.
This aspect is overcome and a description entirely in transverse momentum of
both processes arises for the first time. The small difference between the
simultaneous fit and the one for HERA data alone suggests that the AGBS model
describes very well both kind of processes and thus emerges as a good tool to
investigate the inclusive hadron production data. We use this model for
predictions at LHC energies, which agree very well with available experimental
data.Comment: 10 pages, 7 figure
Secondary schooling and rural youth transitions in Lesotho and Zimbabwe
Based on case studies centred on two rural secondary schools in Lesotho and Zimbabwe, this paper examines the gendered impacts of schooling on young people’s transitions to adulthood. School attendance is shown, first, to disrupt the conventional pathways to adulthood: young people attending school may leave home sooner than they otherwise would, and take responsibility for their day-to-day survival, while marriage and childbearing are often delayed. More significantly, secondary schooling reflects, and contributes to, a growing sense that adulthood itself is not fixed. An alternative version of adulthood is promoted through schools in which formal sector employment is central. Yet while young people are encouraged to opt for, and work towards, this goal, only a minority are able to obtain paid employment. The apparent possibility of determining one’s own lifecourse serves to cast the majority of young people as failures in their transitions to adulthood
Evaluation of a measles vaccine campaign by oral-fluid surveys in a rural Kenyan district: interpretation of antibody prevalence data using mixture models
We evaluated the effectiveness of a measles vaccine campaign in rural Kenya, based on oral-fluid surveys and mixture-modelling analysis. Specimens were collected from 886 children aged 9 months to 14 years pre-campaign and from a comparison sample of 598 children aged 6 months post-campaign. Quantitative measles-specific antibody data were obtained by commercial kit. The estimated proportions of measles-specific antibody negative in children aged 0–4, 5–9 and 10–14 years were 51%, 42% and 27%, respectively, pre- campaign and 18%, 14% and 6%, respectively, post-campaign. We estimate a reduction in the proportion susceptible of 65–78%, with ~85% of the population recorded to have received vaccine. The proportion of ‘weak’ positive individuals rose from 35% pre-campaign to 54% post-campaign. Our results confirm the effectiveness of the campaign in reducing susceptibility to measles and demonstrate the potential of oral-fluid studies to monitor the impact of measles vaccination campaigns
Dilepton distributions at backward rapidities
The dilepton production at backward rapidities in and collisions
at RHIC and LHC energies is investigated in the dipole approach. The results
are shown through the nuclear modification ratio considering
transverse momentum and rapidity spectra. The dilepton modification ratio
presents interesting behavior at the backward rapidities when compared with the
already known forward ones, since it is related with the large kinematical
region that is being probed. The rapidity dependence of the nuclear
modification ratio in the dilepton production is strongly dependent on the
Bjorken behavior of the nuclear structure function ratio
. The transverse momentum dependence at
backward rapidities is modified due to the large nuclear effects: at RHIC
energies, for instance, the ratio is reduced as increases,
presenting an opposite behavior when compared with the forward one. It implies
that the dilepton production at backward rapidities should carry information of
the nuclear effects at large Bjorken , as well as that it is useful to
investigate the dependence of the observables in this kinematical regime.Comment: 15 pages, 6 figures. Version published in the Phys. Rev.
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