1,354,208 research outputs found
Evolution Equations for Extended Dihadron Fragmentation Functions.
No full textAbstractWe consider dihadron fragmentation functions, describing the fragmentation of a parton in two unpolarized hadrons, and in particular extended dihadron fragmentation functions, explicitly dependent on the invariant mass, Mh, of the hadron pair. We first rederive the known results on Mh-integrated functions using jet calculus techniques, and then we present the evolution equations for extended dihadron fragmentation functions. Our results are relevant for the analysis of experimental measurements of two-particle-inclusive processes at different energies
An application of transverse momentum dependent evolution equations in QCD
No full textAbstractThe properties and behaviour of the solutions of the recently obtained kt-dependent QCD evolution equations are investigated. When used to reproduce transverse momentum spectra of hadrons in Semi-Inclusive DIS, an encouraging agreement with data is found. The present analysis also supports at the phenomenological level the factorization properties of the Semi-Inclusive DIS cross-sections in terms of kt-dependent distributions. Further improvements and possible developments of the proposed evolution equations are envisaged
NLO semi-inclusive Drell–Yan cross-section in quantum chromodynamics as a factorization analyzer
No full textAbstractWe evaluate in perturbative QCD the semi-inclusive Drell–Yan cross-section for the production of a single hadron accompanying the lepton pair. We demonstrate to one loop level a collinear factorization formula within the fracture functions approach. We propose such a process as a factorization analyzer in hadronic collisions. Phenomenological implications at the hadron colliders are briefly discussed
On the QCD evolution of transverse momentum dependent distributions
No full textAbstractWe 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 are consistent with each other
Relativistic effects in model calculations of double parton distribution functions
No full textpeer reviewedIn this paper we consider double-parton distribution functions (dPDFs), which are the main nonperturbative ingredients appearing in the double-parton scattering cross section formula in hadronic collisions. By using recent calculation of dPDFs by means of constituent quark models within the so-called light-front approach, we investigate the role of relativistic effects on dPDFs. We find, in particular, that the so-called Melosh operators, which allow us to properly convert the LF spin into the canonical one and incorporate a proper treatment of boosts, produce sizeable effects on dPDFs. We discuss specific partonic correlations induced by these operators in the transverse plane which are relevant to the proton structure, and we study under which conditions these results are stable against variations in the choice of the proton wave function. © 2017 American Physical Society
Valutazione della qualità delle acque e dell'ambiente mediante l'Indice Biologico Esteso (macroinvertebrati): Fiume Frigido
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A VLSI front-end circuit for microstrip silicon detectors for medical imaging applications
No full textAn analog CMOS-Integrated Circuit has been developed as Front-End for a double-sided microstrip silicon detector. The IC processes and discriminates signals in the 5-30 keV energy range. Main features are low noise and precise timing information. Low noise is achieved by optimizing the cascoded integrator with the 8 pF detector capacitance and by using an inherently low noise 1.2 μm CMOS technology. Timing information is provided by a double discriminator architecture. The output of the circuit is a digital pulse. The leading edge is determined by a fixed threshold discriminator, while the trailing edge is provided by a zero crossing discriminator. In this paper we first describe the architecture of the Front-End chip. We then present the performance of the chip prototype in terms of noise, minimum discrimination threshold and time resolution
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