1,246 research outputs found
Buoyant Venus station mission feasibility study for 1972 and 1973 launch opportunities. Volume 2 - Trajectory analysis for 1972 and 1973 missions Final report
Trajectory analysis for 1972 and 1973 buoyant Venus station missio
Testing saturation with diffractive jet production in deep inelastic scattering
We analyse the dissociation of a photon in diffractive deep inelastic
scattering in the kinematic regime where the diffractive mass is much bigger
than the photon virtuality. We consider the dominant q\bar{q}g component
keeping track of the transverse momentum of the gluon which can be measured as
a final-state jet. We show that the diffractive gluon-jet production
cross-section is strongly sensitive to unitarity constraints. In particular, in
a model with parton saturation, this cross-section is sensitive to the scale at
which unitarity effects become important, the saturation scale. We argue that
the measurement of diffractive jets at HERA in the limit of high diffractive
mass can provide useful information on the saturation regime of QCD.Comment: 12 pages, 5 figures, misprints corrected, published versio
Forward di-jet production in p+Pb collisions in the small-x improved TMD factorization framework
We study the production of forward di-jets in proton-lead and proton-proton
collisions at the Large Hadron Collider. Such configurations, with both jets
produced in the forward direction, impose a dilute-dense asymmetry which allows
to probe the gluon density of the lead or proton target at small longitudinal
momentum fractions. Even though the jet momenta are always much bigger than the
saturation scale of the target, , the transverse momentum imbalance of the
di-jet system may be either also much larger than , or of the order ,
implying that the small- QCD dynamics involved is either linear or
non-linear, respectively. The small- improved TMD factorization framework
deals with both situation in the same formalism. In the latter case, which
corresponds to nearly back-to-back jets, we find that saturation effects induce
a significant suppression of the forward di-jet azimuthal correlations in
proton-lead versus proton-proton collisions.Comment: 6 figure
Improved TMD factorization for forward dijet production in dilute-dense hadronic collisions
We study forward dijet production in dilute-dense hadronic collisions. By
considering the appropriate limits, we show that both the
transverse-momentum-dependent (TMD) and the high-energy factorization formulas
can be derived from the Color Glass Condensate framework. Respectively, this
happens when the transverse momentum imbalance of the dijet system, , is
of the order of either the saturation scale, or the hard jet momenta, the
former being always much smaller than the latter. We propose a new formula for
forward dijets that encompasses both situations and is therefore applicable
regardless of the magnitude of . That involves generalizing the TMD
factorization formula for dijet production to the case where the incoming
small- gluon is off-shell. The derivation is performed in two independent
ways, using either Feynman diagram techniques, or color-ordered amplitudes.Comment: The improved version of the manuscript. 37 pages, 8 figures, several
table
Heavy-quark energy loss and thermalization in a strongly coupled SYM plasma
Using the AdS/CFT correspondence, we compute the radiative energy loss of a
slowly decelerating heavy quark with mass M moving through a supersymmetric
Yang Mills (SYM) plasma at temperature T at large t'Hooft coupling \lambda. The
calculation is carried out in terms of perturbation in \sqrt{\lambda}T/M, and
the rate of the energy loss is computed up to second order. We explain the
physical meaning of each correction and estimate the thermalization time of a
heavy quark moving in a strongly-coupled plasma.Comment: 14 pages, 1 figur
Consequences of strong fluctuations on high-energy QCD evolution
We investigate the behaviour of the QCD evolution towards high-energy, in the
diffusive approximation, in the limit where the fluctuation contribution is
large. Our solution for the equivalent stochastic Fisher equation predicts the
amplitude as well as the whole set of correlators in the strong noise limit.
The speed of the front and the diffusion coefficient are obtained. We analyse
the consequences on high-energy evolution in QCD.Comment: 5 pages, 1 figure, more detailed discussions added, version to appear
in Phys. Rev.
Small bowel transplantation: An overview
Small bowel transplantation (SBT) would, in theory, be the treatment of choice for patients suffering from the short bowel syndrome. Although SBT has been done with a considerable degree of success in some centers [36,145], it is by no means an established or widely applicable therapy for those with short bowel syndrome. The small bowel is unique among vascularized organ grafts because it not only elicits a vigorous rejection reaction but is also capable of inducing graft-versus-host disease (GVHD). Rejection of the graft does not only lead to loss of function but also to bacterial translocation. The risk of fatal sepsis is aggravated by the immunosuppression given to prevent rejection. Here, the history of SBT is described, and recent developments in experimental and clinical SBT, as well as future prospects for this theoretically optimal treatment modality for patients dependent on total parenteral nutrition (TPN) for life, are outlined
Diffusive scaling and the high-energy limit of deep inelastic scattering in QCD at large
URL: http://www-spht.cea.fr/articles/T06/001 Processus diffractifs en QCD à haute énergie et grand nombre de couleurs http://fr.arxiv.org/abs/hep-ph/0601150International audienceWithin the limits of the large-- approximation (with the number of colors), we establish the high--energy behaviour of the diffractive and inclusive cross--sections for deep inelastic scattering at fixed impact parameter. We demonstrate that for sufficiently high energies and up to very large values of , well above the proton average saturation momentum , the cross--sections are dominated by dense fluctuations in the target wavefunction, that is, by the relatively rare gluon configurations which are at saturation on the resolution scale of the virtual photon. This has important physical consequences, like the emergence of a new, {\em diffusive}, scaling, which replaces the `geometric scaling' property characteristic of the mean field approximation. To establish this, we shall rely on a dipole version of the Good--Walker formula for diffraction (that we shall derive here in the context of DIS), together with the high--energy estimates for the dipole scattering amplitudes which follow from the recently established evolution equations with Pomeron loops and include the relevant fluctuations. We also find that, as a consequence of fluctuations, the diffractive cross--section at high energy is dominated by the elastic scattering of the quark--antiquark component of the virtual photon, up to relatively large virtualities
Azimuthal decorrelation of Mueller-Navelet jets at the Tevatron and the LHC
We study the production of Mueller-Navelet jets at hadron colliders in the
Balitsky-Fadin-Kuraev-Lipatov (BFKL) framework. We show that a measurement of
the relative azimuthal angle \Delta\Phi between the jets can provide a good
testing ground for corrections due to next-leading logarithms (NLL). Besides
the well-known azimuthal decorrelation with increasing rapidity interval
\Delta\eta between the jets, we propose to also measure this effect as a
function of R=k_2/k_1, the ratio between the jets transverse momenta. Using
renormalisation-group improved NLL kernel, we obtain predictions for
d\sigma/d\Delta\eta dR d\Delta\Phi. We analyse NLL-scheme and
renormalisation-scale uncertainties, and energy-momentum conservation effects,
in order to motivate a measurement at the Tevatron and the LHC.Comment: 11 pages, 7 figures, energy conservation effects adde
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