415 research outputs found
Scanning of the e+e- to pi+pi- cross--section below 1 GeV by radiative events with untagged photon
We discuss an inclusive approach to the measurement of the e+e- --> pi+ pi-
cross--section by the radiative return method without photon tagging. The
essential part of this approach is the choice of rules for event selection
which provide rejection of events with 3 (or more) pions and decrease the
final--state radiation background. The radiative corrections to the
initial--state radiation process are computed for DAPhNE conditions, using the
quasi--real electron approximation for both, the cross--section and the
underlying kinematics. The two cases of restricted and unrestricted pion phase
space are considered. Some numerical calculations illustrate our analytical
results.Comment: 25 pages, 4 figures, late
Radiative Corrections to the Hadronic Cross-Section Measurement at DAPHNE
The hadronic invariant mass distribution for the process of electron-positron
annihilation into a pair of charged pions accompanied by a photon radiated from
the initial state has been studied for the region of DANE energies. The
Born cross-section and the electromagnetic radiative corrections to it are
calculated for realistic conditions of the KLOE detector. The dependence on the
physical parameters which define the event selection is obtained.Comment: 15 pages, Latex, 21 references, no figure
Hadronic Total Cross-sections Through Soft Gluon Summation in Impact Parameter Space
The Bloch-Nordsieck model for the parton distribution of hadrons in impact
parameter space, constructed using soft gluon summation, is investigated in
detail.
Its dependence upon the infrared structure of the strong coupling constant
is discussed, both for finite as well as singular, but integrable,
. The formalism is applied to the prediction of total proton-proton
and proton-antiproton cross-sections, where screening, due to soft gluon
emission from the initial valence quarks, becomes evident.Comment: 20 pages, Latex2e, input FEYNMAN,12 postscipt figures. Submitted to
PR
Hadronic Equipartition of Quark and Glue Momenta
If the ``glue'' which binds quarks within hadrons takes the form of strings,
then a virial theorem may be derived which shows how the total hadron four
momentum splits up into a quark contribution plus a glue contribution. The
hadrons made up of light quarks exhibit an equipartion of four momentum into
equal parts quarks and glue. The agreement with the experimental ``parton''
distribution four momentum sum rule is quite satisfactory as is the string
fragmentation model.Comment: four pages, RevTeX format, one figure *.ep
Adhesion State Estimation for Electrostatic Gripper Based on Online Capacitance Measure
Electroadhesion is a suitable technology for developing grippers for applications where fragile, compliant or variable shape objects need to be grabbed and where a retention action is typically preferred to a compression force. This article presents a self-sensing technique for electroadhesive devices (EAD) based on the capacitance measure. Specifically, we demonstrate that measuring the variation of the capacitance between electrodes of an EAD during the adhesion can provide useful information to automatically detect the successful grip of an object and the possible loss of adhesion during manipulation. To this aim, a dedicated electronic circuit is developed that is able to measure capacitance variations while the high voltage required for the adhesion is activated. A test bench characterization is presented to evaluate the self-sensing of capacitance during different states: (1) the EAD is far away from the object to be grasped; (2) the EAD is in contact with the object, but the voltage is not active (i.e., no adhesion); and (3) the EAD is activated and attached to the object. Correlation between the applied voltage, object material and shape and capacitance is made. The self-sensing EAD is then demonstrated in a closed-loop robotic application that employs a robot manipulator arm to pick and place objects of different kinds
A Wireless, Battery-Powered Probe Based on a Dual-Tier CMOS SPAD Array for Charged Particle Sensing
A compact probe for charged particle imaging, with potential applications in source activity mapping and radio-guided surgery was designed and tested. The development of this technology holds significant implications for medical imaging, offering healthcare professionals accurate and efficient tools for diagnoses and treatments. To fulfill the portability requirements of these applications, the probe was designed for battery operation and wireless communication with a PC. The core sensor is a dual-layer CMOS SPAD detector, fabricated using 150 nm technology, which uses overlapping cells to produce a coincidence signal and reduce the dark count rate (DCR). The sensor is managed and interfaced with a microcontroller, and custom firmware was developed to facilitate communication with the sensor. The performance of the probe was evaluated by characterizing the on-board SPAD detector in terms of the DCR, and the results were consistent with the characterization measurements taken on the same chip samples using a purposely developed benchtop setup
QCD Corrections to Toponium Production at Hadron Colliders
Toponium production at future hadron colliders is investigated. Perturbative
QCD corrections to the production cross section for gluon fusion are calculated
as well as the contributions from gluon-quark and quark-antiquark collisions to
the total cross section. The dependence on the renormalization and
factorization scales and on the choice of the parton distribution functions is
explored. QCD corrections to the branching ratio of into
are included and the two-loop QCD potential is used to predict
the wave function at the origin. The branching ratio of into , , and is compared with the channel.Comment: 16 pages (latex) 9 figures (postscript) available upon request,
TTP92-3
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