Search results for "Amplitude"
showing 10 items of 1169 documents
Optical properties of oxygen-deficiency related centers in amorphous SiO 2 investigated by synchrotron radiation
2002
We report an investigation of the photoluminescence activity at 4.4 v eV in g -irradiated silica under UV and vacuum-UV excitation by synchrotron radiation. Our results evidence two iso-energetic contributions which can be related to two oxygen-deficient centers variants: ODC(I) and ODC(II). The first, excited within the 7.6 v eV absorption, is detected only at low temperature and has a lifetime of about 2 v ns. The second exhibits two excitation maxima peaked at 5.0 and 6.8 v eV, its amplitude decreases by a factor 2 on increasing the temperature whereas its lifetime has a value of about 4 v ns. These features give new insights on the excitation pathway of the 4.4 v eV emission involving t…
ESR response of phenol compounds for dosimetry of gamma photon beams
2014
Abstract In the present paper we investigate the features of IRGANOX® 1076 phenols as a material for electron spin resonance (ESR) dosimetry. We experimentally analyzed the ESR response of pellets of IRGANOX® 1076 phenols irradiated with 60Co photons. The best experimental parameters (modulation amplitude and microwave power) for dosimetric applications have been obtained. The dependence of ESR signal as function of γ dose is found to be linear in the dose range studied (12–60 Gy) and the lowest measurable dose is found to be of the order of 1 Gy. The signal after irradiation is very stable in the first thirty days. From the point of view of the tissue equivalence, these materials have mass…
Numerical exploration of three relativistic particles in a finite volume including two-particle resonances and bound states
2019
In this work, we use an extension of the quantization condition, given in Ref. [1], to numerically explore the finite-volume spectrum of three relativistic particles, in the case that two-particle subsets are either resonant or bound. The original form of the relativistic three-particle quantization condition was derived under a technical assumption on the two-particle K matrix that required the absence of two-particle bound states or narrow two-particle resonances. Here we describe how this restriction can be lifted in a simple way using the freedom in the definition of the K-matrix-like quantity that enters the quantization condition. With this in hand, we extend previous numerical studie…
Study ofe+e−→pp¯π0in the vicinity of theψ(3770)
2014
The process e(+)e(-) -> p (p) over bar pi(0) has been studied by analyzing data collected at root s = 3.773 GeV, root s = 3.650 GeV, and during a psi(3770) line shape scan with the BESIII detector at the BEPCII collider. The Born cross section of p (p) over bar pi(0) in the vicinity of the psi(3770) is measured, and the Born cross section of psi(3770) -> p (p) over bar pi(0) is extracted considering interference between resonant and continuum production amplitudes. Two solutions with the same probability and a significance of 1.5 sigma are found. The solutions for the Born cross section of psi(3770) -> p (p) over bar pi(0) are 33.8 +/- 1.8 +/- 2.1 pb and 0.06(-0.04-0.01)(+0.10+0.01) pb ( ->…
Amplitude analysis and branching-fraction measurement of Ds+→KS0K−π+π+
2021
Using 6.32 fb−1 of e+e− collision data collected by the BESIII detector at the center-of-mass energies between 4.178 and 4.226 GeV, an amplitude analysis of the D+s → K0SK−π+π+ decays is performed ...
Three-Body Coulomb Effects in the Direct Coulomb Breakup of 8B into 7Be + p in the Field of a 208Pb Ion
1999
The amplitude for the Coulomb breakup of a light nucleus in the field of a highly charged ion is considered in the framework of the distorted wave approach, with particular emphasis being laid on correctly taking into account the three-body Coulomb interactions in the final state. Numerical calculations have been performed for the double differential cross section for the reaction 208Pb(8B, 7Be p)208Pb. They clearly demonstrate the importance of long-range three-body Coulomb correlations in the astrophysically interesting regime when the ejectiles have the extremely small relative energies.
Dispersive approach to the nuclear compton amplitude and exchange effects
1981
We discuss the limitation of the standard approach to exchange current effects from photonuclear sum rules. We propose to look for an energy-independent contribution to the real part of the forward Compton-scattering amplitude below pion threshold. Experimental data on photonuclear cross-sections are used to calculate the real part of the amplitude, by means of an once-subtracted dispersion relation. The analysis is made for2H,7Li and9Be at energies varying between 50 and 150 MeV. A remarkably stable value ofK=0.60 is extracted for deuterium. For 1p shell nuclei, the main uncertainty is due to the lack of data above 300 MeV.
Nuclear pion photoproduction in theΔresonance region
1999
A measurement of the /sup 12/C( gamma , pi /sup +/n)/sup 11/B reaction in quasifree pi -production kinematic regimes has been performed using tagged photons in conjunction with large solid angle pi and n detectors. The aim of the experiment was to investigate predicted modifications to the Delta excitation of nucleons and their subsequent propagation and decay, brought about by the nuclear medium. Differential cross sections are presented for photon energies spanning the Delta (1232) excitation region. The measurements are consistent with distorted wave impulse approximation calculations in which the amplitude for proton Delta excitation, followed by Delta propagation and decay to pi /sup +…
Dipole amplitude with uncertainty estimate from HERA data and applications in Color Glass Condensate phenomenology
2014
We determine the initial condition for the small-x evolution equation (BK) from the HERA deep inelastic scattering data using a new parametrization that also keeps the unintegrated gluon distribution positive. The obtained dipole amplitude and its uncertainty estimate can be used to compute single inclusive particle production in proton-proton and proton-nucleus collisions. We argue that one has to use consistently the proton transverse area measured in DIS and the total inelastic cross section when calculating the single inclusive cross section. This leads to a midrapidity nuclear modification factor RpA that approaches unity at large transverse momentum, independently of the center-of-mas…
Three-Body Analysis of Incoherent Photoproduction of η Mesons on the Deuteron near Threshold
2003
The importance of three-body dynamics in the ηnp system in elastic and inelastic η-deuteron scattering as well as coherent and incoherent η photo-production on the deuteron in the energy region from threshold up to 30 MeV above has been investigated. It is shown that a restriction to first order rescattering with respect to the NN- and ηN-final state interactions, i.e., restriction to rescattering in the two-body subsystems, does not give a sufficiently accurate approximation to the s-wave reaction amplitude and that higher order terms, as described by the three-body dynamics give very substantial contributions.