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SUMMARY:Internal Seminar by Wanli Ju
DTSTART;VALUE=DATE-TIME:20210312T140000Z
DTEND;VALUE=DATE-TIME:20210312T150000Z
DTSTAMP;VALUE=DATE-TIME:20211129T093000Z
UID:indico-event-994@conference.ippp.dur.ac.uk
DESCRIPTION:Title:\n\nTransverse momentum resummation in the azimuthal spe
ctra of Drell-Yan processes\n\nAbstract: \n\nTo propose an alternative po
rtal to the W/Z correlations\, the azimuthal opening angle $\\phi_{L}$ bet
ween the final leptons is investigated in this work. In the fixed-order co
ntext\, the calculation on the $\\phi_L$ distribution is not straightforwa
rd\, as the soft and collimated beam radiations in the regime of $\\phi_L\
\to\\pi$ or $q_T\\to 0$ give rise to large logarithms bringing down the pe
rturbativity. Hence\, it is essential to carry out the all-perturbativ
e order resummation over those singular behaviors\, such as $\\ln[q_T/M_{V
}]$. To accomplish this goal\, the soft-collinear effective theory is ut
ilized in this work to factorize and exponentiate those $\\ln[q_T/M_{V}]
$ terms. Thanks to the rapid developments of the fixed-order studies\,
the beam and soft ingredients for this method have been computed up to t
he three-loop level\, which permits us to access the N$^3$LL$'$ evaluation
s. In tacking the hard sectors\, not only are the non-singlet amplitud
es comprised in the calculation\, the singlet influences are also addresse
d for the neutral DY process particularly. As to the later case\, we emplo
y the axial-vector effective field theory to integrate out the heavy quark
impacts and recollect the hard ingredients. The according anomalous dimen
sions and perturbative expressions can be extracted from the anomaly-dep
endent quark form factors.\n\nFor the numerical outputs\, the comparison b
etween the singular and QCD contributions are presented at first. Their
agreements can be obviously observed in the vicinity of $q_T=0$. Besides t
hat\, the resummation-improved results (from NLL$'$ to N$^3$LL$'$) are e
xhibited as well. It is found that as to the majority of regions\, the N
$^{3(2)}$LL$'$ results are well situated in the N$^{2(1)}$LL$'$ error ba
nds\, and with the accuracy growing\, the decrease in the theoretical unce
rtainties is substantial.\n\n \n\nZoom link: IPPP Seminars (Friday at 2
pm UK time)\n\nhttps://durhamuniversity.zoom.us/j/99420124988?pwd=ZEFLSDB
3THJtaWZOTU54R25mT1NuZz09\n\nMeeting ID: 994 2012 4988\nhttps://conference
.ippp.dur.ac.uk/event/994/
URL:https://conference.ippp.dur.ac.uk/event/994/
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