Non-leading mass effects in the effective weak Hamiltonian for Δc = 1 decays

1982 ◽  
Vol 60 (8) ◽  
pp. 1163-1167
Author(s):  
Gerry McKeon

Recently Altarelli, Curci, Martinelli, and Petrarca have calculated the second order corrections induced by quantum chromodynamics to the effective weak Hamiltonian in Δc = 1 processes. We extend their analysis by including the effects of the heavy t and b quarks. The technique used is that first introduced by Witten to study the effects of heavy quarks in deep inelastic scattering and used by Gilman and Wise and Guberina and Peccei to discuss how quark masses alter the effective weak Hamiltonian to leading order in [Formula: see text] processes.

2019 ◽  
Vol 79 (12) ◽  
Author(s):  
T. Gehrmann ◽  
A. Huss ◽  
J. Mo ◽  
J. Niehues

AbstractWe compute the next-to-next-to-leading order (NNLO) QCD corrections to event shape distributions and their mean values in deep inelastic lepton–nucleon scattering. The magnitude and shape of the corrections varies considerably between different variables. The corrections reduce the renormalization and factorization scale uncertainty of the predictions. Using a dispersive model to describe non-perturbative power corrections, we compare the NNLO QCD predictions with data from the H1 and ZEUS experiments. The newly derived corrections improve the theory description of the distributions and of their mean values.


2016 ◽  
Vol 40 ◽  
pp. 1660027
Author(s):  
Fabienne Kunne

We present preliminary COMPASS results on pion and kaon multiplicities produced in semi inclusive deep inelastic scattering of 160[Formula: see text]GeV muons off an isoscalar ([Formula: see text]LiD) target. The results constitute an impressive data set of more than 400 points in p and 400 in K, covering a large x,Q[Formula: see text] and z domain in a fine binning, which will be used in future QCD fits at next to leading order to extract quark fragmentation functions. We show results of a first leading order fit performed to extract the favored and unfavored quark fragmentation functions into pions D[Formula: see text] and D[Formula: see text].


2010 ◽  
Vol 834 (1-2) ◽  
pp. 116-162 ◽  
Author(s):  
Stefano Forte ◽  
Eric Laenen ◽  
Paolo Nason ◽  
Juan Rojo

1992 ◽  
Vol 07 (29) ◽  
pp. 2695-2702 ◽  
Author(s):  
PRAKASH MATHEWS ◽  
V. RAVINDRAN

We analyze polarized Drell-Yan process using the factorization method and derive operator definitions for polarized parton distribution functions. We demonstrate that a factorization analogous to that in the unpolarized Drell-Yan case holds in this process. We study the leading order gluonic contribution to the first moment of polarized Drell-Yan function and show that it is consistent with the results obtained from polarized deep inelastic scattering.


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