4,944 research outputs found
Quenching of Leading Jets and Particles: the p_t Dependent Landau-Pomeranchuk-Migdal effect from Nonlinear k_t Factorization
We report the first derivation of the Landau-Pomeranchuk-Migdal effect for
leading jets at fixed values of the transverse momentum p_t in the beam
fragmentation region of hadron-nucleus collisions from RHIC (Relativistic Heavy
Ion Collider) to LHC (Large Hadron Collider). The major novelty of this work is
a derivation of the missing virtual radiative pQCD correction to these
processes - the real-emission radiative corrections are already available in
the literature. We manifestly implement the unitarity relation, which in the
simplest form requires that upon summing over the virtual and real-emission
corrections the total number of scattered quarks must exactly equal unity. For
the free-nucleon target, the leading jet spectrum is shown to satisfy the
familiar linear Balitsky-Fadin-Kuraev-Lipatov leading log(1/x) (LL-1/x)
evolution. For nuclear targets, the nonlinear k_t-factorization for the LL-1/x
evolution of the leading jet sepctrum is shown to exactly match the equally
nonlinear LL-1/x evolution of the collective nuclear glue - there emerges a
unique linear k_t-factorization relation between the two nonlinear evolving
nuclear observables. We argue that within the standard dilute uncorrelated
nucleonic gas treatment of heavy nuclei, in the finite energy range from RHIC
to LHC, the leading jet spectrum can be evolved in the LL-1/x
Balitsky-Kovchegov approximation. We comment on the extension of these results
to, and their possible reggeon field theory interpretation for, mid-rapidity
jets at LHC.Comment: 36 pages, 8 eps figs, revised, discussion on reggeon interpretation
and refs. adde
Rheological Characteristics of Loam Compositions with Mineral Additives of Different Genesis and Morfology
Structural clay products manufacturing is depends on the potential of local raw materials. Shoddy silty loams are the main component of molding mixtures in view of shortage of the quality clays. Therefore, methods for determining the structural characteristics of molding compounds are becoming important. The objective of study is the influence of mineral additives different genesis and morphology at structural characteristics and molding properties of the compounds based on shoddy silty loams. Photometrical sedimentometer FSH-6K and optical microscopy method were used for the determining of granulometric compositions and morphological properties of the additives. Conical rheometer method was used for the determining plastic strength of the moulding compounds. Shear plastometer method was used to determining values of the low elastic, high elastic and plastic deformations. It had defined the optimal values of molding clay compound’s moisture in which molding compositions had being tested. Optimal values of the molding composition’s moisture in which molding compounds has not subjected to negative influences of the gravitational water are equal to 15-19%. Structural constants were calculated for molding compositions based on different kinds of additives. Values of the percent of low elastic, high elastic and plastic deformation were calculated on the grounds of rheological curves. Optimal values of composition’s structural characteristics were accepted from the condition of three types of deformations
Glue in the pomeron from nonlinear k_\perp-factorization
We derive the nonlinear k_\perp-factorization for the spectrum of jets in
high-mass diffractive deep inelastic scattering as a function of three hard
scales - the virtuality of the photon Q^2, the transverse momentum of the jet
and the saturation scale Q_A. In contrast to all other hard reactions studied
so far, we encounter a clash between the two definitions of the glue in the
pomeron -- from the inclusive spectrum of leading quarks and the small-\beta
evolution of the diffractive cross section. This clash casts a further shadow
on customary applications of the familiar collinear factorization to a pQCD
analysis of diffractive deep inelastic scattering.Comment: 9 page
Revisiting the 'LSND anomaly' II: critique of the data analysis
This paper, together with a preceding paper, questions the so-called 'LSND
anomaly': a 3.8 sigma excess of antielectronneutrino interactions over standard
backgrounds, observed by the LSND Collaboration in a beam dump experiment with
800 MeV protons. That excess has been interpreted as evidence for the
antimuonneutrino to antielectronneutrino oscillation in the \Deltam2 range from
0.2 eV2 to 2 eV2. Such a \Deltam2 range is incompatible with the widely
accepted model of oscillations between three light neutrino species and would
require the existence of at least one light 'sterile' neutrino. In a preceding
paper, it was concluded that the estimates of standard backgrounds must be
significantly increased. In this paper, the LSND Collaboration's estimate of
the number of antielectronneutrino interactions followed by neutron capture,
and of its error, is questioned. The overall conclusion is that the
significance of the 'LSND anomaly' is not larger than 2.3 sigma.Comment: 30 pages, 16 figures, 6 table
Reply to 'Corrections to the HARP-CDP Analysis of the LSND Neutrino Oscillation Backgrounds'
The alleged mistakes in recent papers that reanalyze the backgrounds to the
'LSND anomaly' do not exist. We maintain our conclusion that the significance
of the 'LSND anomaly' is not 3.8 sigma but not larger than 2.3 sigma.Comment: 3 page
Interaction of Wilson loops in confining vacuum
Nonperturbative and perturbative interaction mechanisms of Wilson loops in
gluodynamics are studied within the background field formalism. The first one
operates when distance between minimal surfaces of the loops is small and may
be important for sea quark effects and strong decay processes. The second
mechanism -- perturbative interaction in nonperturbative confining background
is found to be physically dominant for all loop configurations characteristic
of scattering process. It reduces to perturbative gluon exchanges at small
distances, while at larger distances it corresponds to the t-channel exchange
of (reggeized) glueball states.
Comparison to other approaches is made and possible physical applications are
discussed.Comment: LaTeX, 25 pages, 5 EPS-figure
Cross-sections of large-angle hadron production in proton- and pion-nucleus interactions VII: tin nuclei and beam momenta from \pm3 GeV/c to \pm15 GeV/c
We report on double-differential inclusive cross-sections of the production
of secondary protons, charged pions, and deuterons, in the interactions with a
5% nuclear interaction length thick stationary tin target, of proton and pion
beams with momentum from \pm3 GeV/c to \pm15 GeV/c. Results are given for
secondary particles with production angles between 20 and 125 degrees.
Cross-sections on tin nuclei are compared with cross-sections on beryllium,
carbon, copper, tantalum and lead nuclei.Comment: 68 pages, 13 figure
From EMC- and Cronin-effects to signals of quark-gluon plasma
The EMC- and Cronin-effects are explained by a unitarized evolution equation,
where the shadowing and antishadowing corrections are dynamically produced by
gluon fusions. For this sake, an alternative form of the GLR-MQ-ZRS equation is
derived. The resulting integrated and unintegrated gluon distributions in
proton and nuclei are used to analyze the contributions of the initial parton
distributions to the nuclear suppression factor in heavy ion collisions. A
simulation of the fractional energy loss is extracted from the RHIC and LHC
data, where the contributions of the nuclear shadowing and antishadowing
effects are considered. We find a rapid crossover from week energy loss to
strong energy loss at a universal critical energy of gluon jet .Comment: 35 pages, 13 figures, to be published in Int. J. Mod. Phys.
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