اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدZZ production at high transverse momenta beyond NLO QCD
119
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We study the production of the four-lepton final state $l^+ l^- l^+ l^-$, predominantly produced by a pair of electroweak Z bosons, ZZ. Using the LoopSim method, we merge NLO QCD results for ZZ and ZZ+jet and obtain approximate NNLO predictions for ZZ production. The exact gluon-fusion loop-squared contribution to the ZZ process is also included. On top of that, we add to our merged sample the gluon-fusion ZZ+jet contributions from the gluon-gluon channel, which is formally of N^3LO and provides approximate results at NLO for the gluon-fusion mechanism. The predictions are obtained with the VBFNLO package and include the leptonic decays of the Z bosons with all off-shell and spin-correlation effects, as well as virtual photon contributions. We compare our predictions with existing results for the total inclusive cross section at NNLO and find a very good agreement. Then, we present results for differential distributions for two experimental setups, one used in searches for anomalous triple gauge boson couplings, the other in Higgs analyses in the four charged-lepton final state channel. We find that the approximate NNLO corrections are large, reaching up to 20% at high transverse momentum of the Z boson or the leading lepton, and are not covered by the NLO scale uncertainties. Distributions of the four-lepton invariant mass are, however, stable with respect to QCD corrections at this order.
قيم البحث
اقرأ أيضاً
A fully differential calculation of the next-to-leading order QCD corrections to the production of Z-boson pairs in association with a hard jet at the Tevatron and LHC is presented. This process is an important background for Higgs particle and new p
hysics searches at hadron colliders. We find sizable corrections for cross sections and differential distributions, particularly at the LHC. Residual scale uncertainties are typically at the 10% level and can be further reduced by applying a veto against the emission of a second hard jet. Our results confirm that NLO corrections do not simply rescale LO predictions.
We study WZ production with anomalous couplings at $bar{n}$NLO QCD using the LoopSim method in combination with the Monte Carlo program VBFNLO. Higher order corrections to WZ production are dominated by additional hard jet radiation. Those contributi
ons are insensitive to anomalous couplings and should thus be removed in analyses. We do this using a dynamical jet veto based on the transverse energy of the QCD and EW final state particles. This removes jet dominated events without introducing problematic logs like a fixed $p_{text{T}}$ jet veto.
We consider QCD radiative corrections to the production of four charged leptons in hadron collisions. We present the computation of the next-to-leading order QCD corrections to the loop-induced gluon fusion contribution. Our predictions include, for
the first time, also the quark-gluon partonic channels. The computed corrections, which are formally of ${cal O}(alpha_{rm s}^3)$, turn out to increase the loop-induced Born-level result by an amount ranging from 75% to 71% as $sqrt{s}$ ranges from 8 to 13 TeV. We combine our result with state-of-the-art NNLO corrections to the quark annihilation channel, and present updated predictions for fiducial cross sections and distributions for this process.
Measuring the polarization of electroweak bosons at the LHC allows for important tests of the electroweak-symmetry-breaking mechanism that is realized in nature. Therefore, precise Standard Model predictions are needed for the production of polarized
bosons in the presence of realistic kinematic selections. We formulate a method for the calculation of polarized cross-sections at NLO that relies on the pole approximation and the separation of polarized matrix elements at the amplitude level. In this framework, we compute NLO-accurate cross-sections for the production of two polarized Z bosons at the LHC, including for the first time NLO EW corrections and combining them with NLO QCD corrections and contributions from the gluon-induced process.
We present the first calculation of the full next-to-leading-order electroweak and QCD corrections for vector-boson scattering (VBS) into a pair of Z bosons at the LHC. We consider specifically the process ${rm ppto e^{+}e^{-}mu^{+}mu^{-}jj}+X$ at or
ders $mathcal{O}(alpha^7)$ and $mathcal{O}(alpha_salpha^6)$ and take all off-shell and interference contributions into account. Owing to the presence of enhanced Sudakov logarithms, the electroweak corrections amount to $-16%$ of the leading-order electroweak fiducial cross section and induce significant shape distortions of differential distributions. The QCD corrections on the other hand are larger ($+24%$) than typical QCD corrections in VBS. This originates from considering the full computation including tri-boson contributions in a rather inclusive phase space. We also provide a leading-order analysis of all contributions to the cross section for ${rm pp to e^{+}e^{-}mu^{+}mu^{-}jj}+X$ in a realistic setup.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
