4,567 research outputs found
TMD evolution and the Higgs transverse momentum distribution
The effect of the linear polarization of gluons on the transverse momentum
distribution in Higgs production is studied within the framework of TMD
factorization. For this purpose we consider the TMD evolution for general
colorless scalar boson production, from the lower mass -even scalar
quarkonium states and to the Higgs mass scale. In the
absence of an intrinsic nonperturbative linearly polarized gluon distribution
the results correspond to the CSS formalism, indicating a rather rapid decrease
with increasing energy scale. At the Higgs mass scale the contribution from
linearly polarized gluons is in this case found to be on the percent level,
somewhat larger than an earlier finding in the literature. At the lower mass
scale of quarkonium states and we find contributions at
the 15-70% level, albeit with considerable uncertainty. In the presence of an
intrinsic linear gluon polarization, percent level effects are also found at
the Higgs mass scale, but with a considerably slower evolution. Although these
results were obtained using a model for the TMDs that are approximately
Gaussian at small transverse momenta and have the correct perturbative power
law fall off at large transverse momenta, it illustrates well the differences
that can exist between results obtained from a TMD formalism as compared to a
CSS formalism. The behavior of the TMDs at small can affect the results
for all transverse momenta of the produced boson, even for a particle as heavy
as the Higgs. The TMD evolution from to may be used to
constrain the nonperturbative contributions and improve on the prediction of
the effect at the Higgs mass scale.Comment: 12 pages, 5 figures, minor additions, matches version accepted for
publication in Nuclear Physics
The development of a resource-efficient photovoltaic system
This paper presents the measures taken in the demonstration of the photovoltaic case study developed within the European project ‘Towards zero waste in industrial networks’ (Zerowin), integrating the D4R (Design for recycling, repair, refurbishment and reuse) criteria at both system and industrial network level. The demonstration is divided into three phases. The first phase concerns the development of a D4R photovoltaic concept, the second phase focused on the development of a specific component of photovoltaic systems and the third phase was the demonstration of the D4R design in two complete photovoltaic systems (grid-connected and stand-alone). This paper includes a description of the installed photovoltaic systems, including a brief summary at component level of the lithium ion battery system and the D4R power conditioning system developed for the pilot installations. Additionally, industrial symbioses within the network associated with the photovoltaic systems and the production model for the network are described
Linearly Polarized Gluons and the Higgs Transverse Momentum Distribution
We study how gluons carrying linear polarization inside an unpolarized hadron
contribute to the transverse momentum distribution of Higgs bosons produced in
hadronic collisions. They modify the distribution produced by unpolarized
gluons in a characteristic way that could be used to determine whether the
Higgs boson is a scalar or a pseudoscalar particle.Comment: 4 pages, 3 figures, final version, published in PR
Double Sivers effect asymmetries and their impact on transversity measurements at RHIC
We study double transverse spin asymmetries in the Drell-Yan process at
measured transverse momentum of the lepton pair. Contrary to what a collinear
factorization approach would suggest, a nonzero double transverse spin
asymmetry in the laboratory frame a priori does not imply nonzero transversity.
TMD effects, such as the double Sivers effect, in principle form a background.
Using the current knowledge of the relevant TMDs we estimate their contribution
in the laboratory frame for Drell-Yan and W production at RHIC and point out a
cross check asymmetry measurement to bound the TMD contributions. We also
comment on the transverse momentum integrated asymmetries that only receive
power suppressed background contributions.Comment: 12 pages, 11 eps figures, minor changes, matches the published
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