Search results for "Cross Section"
showing 10 items of 3111 documents
Thermal neutron capture cross sections of tellurium isotopes
2003
New values for thermal neutron capture cross sections of the tellurium isotopes 122Te, 124Te, 125Te, 126Te, 128Te, and 130Te are reported. These values are based on a combination of newly determined partial g-ray cross sections obtained from experiments on targets contained natural Te and gamma intensities per capture of individual Te isotopes. Isomeric ratios for the thermal neutron capture on the even tellurium isotopes are also given.
The Pion Single-Event Latch-Up Cross Section Enhancement: Mechanisms and Consequences for Accelerator Hardness Assurance
2021
Pions make up a large part of the hadronic environment typical of accelerator mixed fields. Characterizing device cross sections against pions is usually disregarded in favor of tests with protons, whose single-event latch-up (SEL) cross section is, nonetheless, experimentally found to be lower than that of pions for all energies below 250 MeV. While Monte Carlo simulations are capable of reproducing such behavior, the reason for the observed pion cross-section enhancement can only be explained by a deeper analysis of the underlying mechanisms dominating proton–silicon and pion–silicon reactions. The mechanisms dominating the SEL response are found to vary with the energy under consideratio…
Out-of-plane measurements of the fifth response function of the exclusive electronuclear response
1999
The first measurements of f{sub LT}{sup '}, known as the fifth response function, have been made for the {sup 2}H(e(vector sign),e{sup '}p) and {sup 12}C(e(vector sign),e{sup '}p) reactions. This response is directly related to the imaginary part of the interference between the transverse and longitudinal nuclear electromagnetic currents. Its observation requires longitudinally polarized electron beams and out-of-plane detection, the latter made possible by the newly developed out-of-plane spectrometer system. The initial measurements were made by using a 560-MeV polarized electron beam and quasielastic kinematics at Q{sup 2}=3.3 fm{sup -2}. The development of the methodology for out-of-pla…
Evidence for e+e−→γηc(1S) at center-of-mass energies between 4.01 and 4.60 GeV
2017
We present first evidence for the process e(+)e(-) -> gamma eta(c)(1S) at six center-of-mass energies between 4.01 and 4.60 GeV using data collected by the BESIII experiment operating at BEPCII. We measure the Born cross section at each energy using a combination of twelve eta(c)(1S) decay channels. We also combine all six energies under various assumptions for the energy-dependence of the cross section. If the process is assumed to proceed via the Y(4260), we measure a peak Born cross section sigma(peak)(e(+)e(-) -> gamma eta(c)(1S)) = 2.11 +/- 0.49 (stat.) +/- 0.36 (syst.) pb with a statistical significance of 4.2 sigma.
Updated Z Parameters, and Standard Model Fits from Electroweak Precision Data
1999
Data taking around the Z resonance at LEP I ended in 1995, and determinations of the mass, width, hadronic pole cross section and leptonic couplings of the Z boson are approaching a final status. This is accompanied by an improved understanding of the beam energy during the high-statistics data taking approximately two GeV above and below the Z resonance in 1993 and 1995. Together with other precision measurements presented at this conference impressive tests of the consistency of the Standard Model can be made and an upper limit on the mass of the Higgs boson can be derived.
Impact parameter dependent JIMWLK evolution meets HERA data
2019
We calculate the small-$x$ evolution of protons with finite size by solving numerically the JIMWLK evolution equation. The initial condition is constrained by the HERA measurements of charm reduced cross section and of exclusive vector meson production. We compute the energy dependence of diffractive cross sections in order to access the energy evolution of the event-by-event fluctuating proton density profile. The fundamental problems arising from the regime sensitive to non-perturbatively large dipoles are also discussed.
b-Hadron production in the general-mass variable-flavour-number scheme and LHC data
2018
We study inclusive b-hadron production in pp collisions at the LHC at different center-of-mass energies and compare with experimental data from the LHCb and CMS collaborations. Our predictions for cross sections differential in the transverse momentum and (pseudo-)rapidity agree with data within uncertainties due to renormalization scale variations. A small tension is found if data and theory predictions are compared for cross section ratios at different center-of-mass energies.
Soft gluon resummation for Slepton pair-production
2011
We report on recent results on the differential cross section for slepton pair-production at hadron colliders. We use an approach to threshold resummation, based on soft-collinear effective theory, to quantify the dynamical enhancement of the partonic threshold region. We evaluate the resummed invariant mass distribution and total cross section at next-to-next-to-next-to-leading logarithmic order, and match the result onto next-to-leading order calculation.
Measurement of the Ratioσtt¯/σZ/γ*→lland Precise Extraction of thett¯Cross Section
2010
We report a measurement of the ratio of the t (t) over bar to Z/gamma* production cross sections in root s = 1.96 TeV p (p) over bar collisions using data corresponding to an integrated luminosity of up to 4.6 fb(-1), collected by the CDF II detector. The t (t) over bar cross section ratio is measured using two complementary methods, a b-jet tagging measurement and a topological approach. By multiplying the ratios by the well-known theoretical Z/gamma* -> ll cross section predicted by the standard model, the extracted t (t) over bar cross sections are effectively insensitive to the uncertainty on luminosity. A best linear unbiased estimate is used to combine both measurements with the resul…
Cross section measurement of e+e−→pp¯η and e+e−→pp¯ω at center-of-mass energies between 3.773 GeV and 4.6 GeV
2021
Using data samples with a total integrated luminosity of $20.1~\rm fb^{-1}$ collected by the BESIII detector operating at the BEPCII collider, the cross section of the process $e^+e^- \rightarrow \pi^+\pi^-\psi(3686)$ is measured at center-of-mass energies between 4.0076 and 4.6984 GeV. The measured cross section is consistent with previous results, but with much improved precision. A fit to the measured energy-dependent cross section, which includes three Breit-Wigner functions and a non-resonant contribution, confirms the existence of the charmonium-like states $Y(4220)$, $Y(4390)$, and $Y(4660)$. This is the first observation of the $Y(4660)$ at the BESIII experiment.