29 research outputs found
Estimation of Hydrodynamical Model Parameters from the Invariant Spectrum and the Bose-Einstein Correlations of pi-mesons Produced in (pi+/K+)p Interactions at 250 GeV/c
The invariant spectra of pi- mesons produced in (pi+/K+)p interactions at 250
GeV/c are analysed in the framework of the hydrodynamical model of
three-dimensionally expanding cylindrically symmetric finite systems.
A satisfactory description of experimental data is achieved.
The data favour the pattern according to which the hadron matter undergoes
predominantly longitudinal expansion and non-relativistic transverse expansion
with mean transverse velocity = 0.20(7), and is characterized by a large
temperature inhomogeneity in the transverse direction: the extracted freeze-out
temperature at the center of the tube and at the transverse rms radius are
140(3) MeV and 82(7) MeV, respectively. The width of the (longitudinal)
space-time rapidity distribution of the pion source is found to be Delta eta =
1.36(2).
Combining this estimate with results of the Bose-Einstein correlation
analysis in the same experiment, one extracts a mean freeze-out time of the
source of = 1.4(1) fm/c and its transverse geometrical rms radius, R_G
(rms)=1.2(2) fm.Comment: latex, 14 pages, 5 figure
Estimation of hydrodynamical model parameters from the invariant spectrum and the Bose-Einstein correlations of -mesons produced in ( interactions at 250 GeV/c
The invariant spectra of pi- mesons produced in (pi+/K+)p interactions at 250 GeV/c are analysed in the framework of the hydrodynamical model of three-dimensionally expanding cylindrically symmetric finite systems. A satisfactory description of experimental data is achieved. The data favour the pattern according to which the hadron matter undergoes predominantly longitudinal expansion and non-relativistic transverse expansion with mean transverse velocity = 0.20(7), and is characterized by a large temperature inhomogeneity in the transverse direction: the extracted freeze-out temperature at the center of the tube and at the transverse rms radius are 140(3) MeV and 82(7) MeV, respectively. The width of the (longitudinal) space-time rapidity distribution of the pion source is found to be Delta eta = 1.36(2). Combining this estimate with results of the Bose-Einstein correlation analysis in the same experiment, one extracts a mean freeze-out time of the source of = 1.4(1) fm/c and its transverse geometrical rms radius, R_G (rms)=1.2(2) fm.The invariant spectra of pi- mesons produced in (pi+/K+)p interactions at 250 GeV/c are analysed in the framework of the hydrodynamical model of three-dimensionally expanding cylindrically symmetric finite systems. A satisfactory description of experimental data is achieved. The data favour the pattern according to which the hadron matter undergoes predominantly longitudinal expansion and non-relativistic transverse expansion with mean transverse velocity = 0.20(7), and is characterized by a large temperature inhomogeneity in the transverse direction: the extracted freeze-out temperature at the center of the tube and at the transverse rms radius are 140(3) MeV and 82(7) MeV, respectively. The width of the (longitudinal) space-time rapidity distribution of the pion source is found to be Delta eta = 1.36(2). Combining this estimate with results of the Bose-Einstein correlation analysis in the same experiment, one extracts a mean freeze-out time of the source of = 1.4(1) fm/c and its transverse geometrical rms radius, R_G (rms)=1.2(2) fm
Self-affine scaling from non-integer phase-space partition in and collisions at 250 GeV/
A factorial-moment analysis with real (integer and non-integer) phase space partition is applied to p and Kp collisions at 250 GeV/. Clear evidence is shown for self-affine rather than self-similar power-law scaling in multiparticle production. The three-dimensional self-affine second-order scaling exponent is determined to be 0.0610.010.A factorial-moment analysis with real (integer and non-integer) phase space partition is applied to p and Kp collisions at 250 GeV/. Clear evidence is shown for self-affine rather than self-similar power-law scaling in multiparticle production. The three-dimensional self-affine second-order scaling exponent is determined to be 0.0610.010.A factorial-moment analysis with real (integer and non-integer) phase space partition is applied to p and Kp collisions at 250 GeV/. Clear evidence is shown for self-affine rather than self-similar power-law scaling in multiparticle production. The three-dimensional self-affine second-order scaling exponent is determined to be 0.0610.010.A factorial-moment analysis with real (integer and non-integer) phase space partition is applied to π + p and K + p collisions at 250 GeV/ c . Clear evidence is shown for self-affine rather than self-similar power-law scaling in multiparticle production. The three-dimensional self-affine second-order scaling exponent is determined to be 0.061±0.010
Large Self-affine fractality in \p^+p and Kp collisions at 250 GeV/
Taking into account the anisotropy of phase space in multiparticle
production, a self-affine analysis of factorial moments was carried out on the
NA22 data for \p^+\Pp and \PK^+\Pp collisions at 250 GeV/. Within the
transverse plane, the Hurst exponents measuring the anisotropy are consistent
with unit value (i.e. no anisotropy). They are, however, only half that value
when the longitudinal direction is compared to the transverse ones. Fractality,
indeed, turns out to be self-affine rather than self-similar in multiparticle
production. In three-dimensional phase space, power-law scaling is observed to
be better realized in self-affine than in self-similar analysis.Comment: 10 pages and 4 figure
Electron Scattering From High-Momentum Neutrons in Deuterium
We report results from an experiment measuring the semi-inclusive reaction
where the proton is moving at a large angle relative to the
momentum transfer. If we assume that the proton was a spectator to the reaction
taking place on the neutron in deuterium, the initial state of that neutron can
be inferred. This method, known as spectator tagging, can be used to study
electron scattering from high-momentum (off-shell) neutrons in deuterium. The
data were taken with a 5.765 GeV electron beam on a deuterium target in
Jefferson Laboratory's Hall B, using the CLAS detector. A reduced cross section
was extracted for different values of final-state missing mass ,
backward proton momentum and momentum transfer . The data
are compared to a simple PWIA spectator model. A strong enhancement in the data
observed at transverse kinematics is not reproduced by the PWIA model. This
enhancement can likely be associated with the contribution of final state
interactions (FSI) that were not incorporated into the model. A ``bound neutron
structure function'' was extracted as a function of and
the scaling variable at extreme backward kinematics, where effects of
FSI appear to be smaller. For MeV/c, where the neutron is far
off-shell, the model overestimates the value of in the region of
between 0.25 and 0.6. A modification of the bound neutron structure
function is one of possible effects that can cause the observed deviation.Comment: 33 pages RevTeX, 9 figures, to be submitted to Phys. Rev. C. Fixed 1
Referenc
Charmonium production in Pb-Pb collisions
NA50The elaboration of specific media-planning is necessary to communicate with an opinion leader. Opinion leaders in 27 product categories are selected from a 10,000 sample of French representative consumers. Magazine is the favorite media of opinion leaders; the more important is the number of product categories in which a consumer is leaders, the greater the media consumption. Leaders do not systematically prefer the Internet, their preference appears to be category specific. However, a second study conducted among 600 brand website visitors shows that brand sites represent a major information source for the leaders
Pomeron-pomeron cross-section from inclusive production of a central cluster in quasi-elastic Pi(+)P and K(+)P scattering at 250 Gev/C
Contains fulltext :
29799.PDF (publisher's version ) (Open Access
Collective Sea-Gull Effect in Pi(+)P Interactions at 250 Gev/C
Contains fulltext :
26861___.PDF (publisher's version ) (Open Access
Reactions with leading hadrons in meson-proton interactions at 250 GeV/c
Contains fulltext :
26247.pdf (publisher's version ) (Open Access