Phenomenology of Matching Exponentiated Photonic Radiation to a Parton Shower in KKMChh

Abstract

KKMChh adapts the soft photon exponentiation of the program KKMC, initially for electron-positron annihilation, to hadron collisions, where it must interface to a parton shower and parton distribution functions (PDFs) which may already include effects of QED radiation. We describe the NISR (Negative Initial State Radiation) algorithm developed to consistently interface with PDFs including QED effects, and present results on its effect on some distributions of phenomenological interest.

Figures (6)

• Figure 1: The left graph shows the QED ISR radiator function $\rho_{\rm ISR}(v)$ as a function of the ISR photon energy fraction $v$, and the left graph shows the ratio of the integrand of Eq. (\ref{['eq6']}) to $xL_{q{\bar{q}}}(xs)$ without QED corrections
• Figure 2: The QED-corrected joint parton luminosity functions $x L^{\rm QED}_{q{\bar{q}}}$ for each flavor on the left, together with the ratio to the original NNPDF joint parton luminosity function on the right, for $M_{q{\bar{q}}}$ between 60 and 140 GeV.
• Figure 3: The QED-corrected joint parton luminosity functions $x L^{\rm QED}_{q{\bar{q}}}$ for each flavor on the left, together with the ratio to the original NNPDF joint parton luminosity function on the right, for $M_{q{\bar{q}}}$ up to 1000 GeV.
• Figure 4: The ratio of the up quark QED-corrected joint parton luminosity function $x L^{\rm QED}_{q{\bar{q}}}$ to the original NNPDF joint parton luminosity function with the charge varied from $2e/3$ to $e/3$ to $e$ for energy scales between 60 and 140 GeV on the left and up to 1000 GeV on the right.
• Figure 5: The ratio of the up quark QED-corrected joint parton luminosity function $x L^{\rm QED}_{q{\bar{q}}}$ to the original NNPDF joint parton luminosity function with the mass varied from $m_u = 2.2$ MeV to 4.7 MeV, 320 MeV, and 0.511 MeV, for energy scales between 60 and 140 GeV on the left and up to 1000 GeV on the right.