40 research outputs found
Studies of backward particle production with A Fixed-Target Experiment using the LHC beams
The foreseen capability to cover the far backward region at A Fixed-Target
Experiment using the LHC beams allows to explore the dynamics of target
fragmentation in hadronic collisions. In this report we briefly outline the
required theoretical framework and discuss a number of studies of forward and
backward particle production. By comparing this knowledge with the one
accumulated in Deep Inelastic Scattering on target fragmentation, the basic
concept of QCD factorisation could be investigated in detail.Comment: Contribution to the special issue on "A Fixed-Target Experiment using
the LHC beams". Phenomenological section describing single hard diffraction
added. 8 plots adde
Scale evolution of kt-distributions
We review some of the features of the evolutions equations for transverse
momentum dependent parton distributions recently proposed by us. We briefly
describe the new ingredients entering the equations and their relationship with
ordinary evolution equations. We comment on possible choices for the initial
conditions and then show results for the evolved distributions obtained by
numerical implementation of the equations. By computing the average transverse
momentum at different scale we highlight some general properties of the
solutions.Comment: Contribution to the XVIII International Workshop on Deep-Inelastic
Scattering and Related Subjects, April 19 -23, 2010, Florence, Italy. 5
pages, 2 figure
QCD analysis of forward neutron production in DIS
We consider forward neutron production in DIS within fracture functions
formalism. By performing a QCD analysis of available data we extract
proton-to-neutron fracture functions exploiting a method which is in close
relation with the factorisation theorem for this class of processes.Comment: 18 pages, 5 figures, revtex
Lambda production in the DIS target fragmentation region
By using a recently obtained set of Lambda fracture functions, we present
predictions for Lambda production in the target fragmentation region of
Semi-Inclusive Deep Inelastic Scattering in CLAS@12 GeV kinematics,
supplemented with a conservative error estimates. We discuss a number of
observables sensitive to the assumptions of the underlying theory and many of
the assumptions of the proposed phenomenological model.Comment: 16 pages, 11 figures, updated experimental and theoretical errors
estimation. Accepted for publication in EPJ
A second update on double parton distributions
We present two equivalent consistency checks of the momentum sum rule for
double parton distributions and show the importance of the inclusion of the
so-called inhomogeneous term in order to preserve correct longitudinal momentum
correlations. We further discuss in some detail the kinematics of the splitting
at the basis of the inhomogeneous term and update the double parton
distributions evolution equations at different virtualities.Comment: Two reference added. Additional appendix. Minor changes on the tex
Single-diffractive Drell-Yan pair production at the LHC
We present predictions for single-diffractive low-mass Drell-Yan pair
production in collisions at the LHC at TeV. Predictions are
obtained adopting a factorised form for the relevant cross sections and are
based on a new set of diffractive parton distributions resulting from the QCD
analysis of combined HERA leading proton data. We discuss a number of
observables useful to characterise the expected factorisation breaking effects.Comment: 22 pages, 2 tables, 9 figures. Typos corrected, 3 References adde
QCD analysis of Lambda hyperon production in DIS target-fragmentation region
We consider Lambda-hyperon production in the target-fragmentation region of
semi-inclusive deep-inelastic scattering within the framework of fracture
functions. We present a first attempt to determine the flavour and energy
dependences of these non-perturbative distributions through a simultaneous
QCD-based fit to available neutral- and charged-current semi-inclusive-DIS
cross sections. Predictions based on the resulting nucleon-to-Lambda fracture
functions are in good agreement with data and observables not included in the
regression. The successful prediction of the dependence of the Lambda
multiplicity notably represents the first validation of the perturbative
framework implied by fracture functions.Comment: Detailed comparison to quark-gluon string model added together with 3
additional plots. Three references added. Conclusions unchanged. Minor
corrections to the text. 18 pages, 18 figures, 3 table
Hadronic structure from double parton scattering
In the present paper we consider the so-called effective cross section, a
quantity which encodes the experimental knowledge on double parton scattering
in hadronic collisions that has been accomulated so far. We show that the
effective cross section, under some assumptions close to those adopted in its
experimental extractions, can be used to obtain a range of mean transverse
distance between an interacting parton pair in double parton scattering.
Therefore we have proved that the effective cross section offers a way to
access information on the hadronic structure.Comment: 5 pages, 1 figure. References added and figure updated. Referee
suggestions implemented. Published in PRD rapid communicatio
On the QCD Evolution of Transverse Momentum Dependent Distributions
We reconsider the evolution equations for transverse momentum dependent
distributions recently proposed by us and recast them in a form which allows
the comparison with results recently appeared in the literature. We show under
which conditions the obtained results might be consistent with each other.Comment: 13 pages, no figures, minor changes to text, one reference adde
Revisiting QCD Fits in Diffractive DIS
A new method of extracting diffractive parton distributions is presented
which avoids the use of Regge theory ansatz and is in much closer relation with
the factorisation theorem for diffractive hard processes