scholarly journals Radiochemical study of sub-barrier fusion hindrance in the 19F+209Bi reaction

2011 ◽  
Vol 1 (1) ◽  
pp. 117-121
Author(s):  
I. Nishinaka ◽  
Y. Kasamatsu ◽  
M. Tanikawa ◽  
S. Goto ◽  
M. Asai

AbstractProduction cross sections of fission product 99Mo produced in the reaction of 19F + 209Bi have been measured at the incident energies 135–83 MeV near and below the fusion barrier by radiochemical methods. The excitation function for the fusion-fission cross sections in this reaction were deduced down to 80 μb from the measured production cross sections. A systematic analysis of the fusion-fission excitation function shows that sub-barrier fusion hindrance in the heavy mass system 19F + 209Bi is different from that in the medium-heavy mass systems but similar to that in the medium-light mass system and in the heavy mass system. This work is the first radiochemical study of sub-barrier fusion hindrance in heavy mass systems.

1968 ◽  
Vol 46 (20) ◽  
pp. 3171-3176 ◽  
Author(s):  
V. P. Narang ◽  
L. Yaffe

Absolute values of the cross sections of (p,n), (p,pn), (p,p2n), and (p,p3n) reactions in 127I have been measured by radiochemical methods for incident proton of energies up to 80 MeV. The initial portion of the excitation function for the (p,n) reaction is characteristic of the compound nucleus mechanism, but evidence for direct interaction is present at higher energies. Above 50 MeV, cross sections are close to the predictions of Monte Carlo calculations based on the cascade–evaporation model. This is particularly true in the case of the (p,pn) and (p,p2n) reactions.


2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Markus A. Ebert ◽  
Bernhard Mistlberger ◽  
Gherardo Vita

Abstract We demonstrate how to efficiently expand cross sections for color-singlet production at hadron colliders around the kinematic limit of all final state radiation being collinear to one of the incoming hadrons. This expansion is systematically improvable and applicable to a large class of physical observables. We demonstrate the viability of this technique by obtaining the first two terms in the collinear expansion of the rapidity distribution of the gluon fusion Higgs boson production cross section at next-to-next-to leading order (NNLO) in QCD perturbation theory. Furthermore, we illustrate how this technique is used to extract universal building blocks of scattering cross section like the N-jettiness and transverse momentum beam function at NNLO.


2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
M. V. Garzelli ◽  
L. Kemmler ◽  
S. Moch ◽  
O. Zenaiev

Abstract We present predictions for heavy-quark production at the Large Hadron Collider making use of the $$ \overline{\mathrm{MS}} $$ MS ¯ and MSR renormalization schemes for the heavy-quark mass as alternatives to the widely used on-shell renormalization scheme. We compute single and double differential distributions including QCD corrections at next-to-leading order and investigate the renormalization and factorization scale dependence as well as the perturbative convergence in these mass renormalization schemes. The implementation is based on publicly available programs, MCFM and xFitter, extending their capabilities. Our results are applied to extract the top-quark mass using measurements of the total and differential $$ t\overline{t} $$ t t ¯ production cross-sections and to investigate constraints on parton distribution functions, especially on the gluon distribution at low x values, from available LHC data on heavy-flavor hadro-production.


2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Claude Duhr ◽  
Falko Dulat ◽  
Bernhard Mistlberger

Abstract We present the production cross section for a lepton-neutrino pair at the Large Hadron Collider computed at next-to-next-to-next-to-leading order (N3LO) in QCD perturbation theory. We compute the partonic coefficient functions of a virtual W± boson at this order. We then use these analytic functions to study the progression of the perturbative series in different observables. In particular, we investigate the impact of the newly obtained corrections on the inclusive production cross section of W± bosons, as well as on the ratios of the production cross sections for W+, W− and/or a virtual photon. Finally, we present N3LO predictions for the charge asymmetry at the LHC.


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