NLO QCD corrections to W-b-bbar and Z-b-bbar production
Fernando Febres Cordero, Laura Reina, Doreen Wackeroth
备注：
6 pages, 6 eps figures, LaTeX, to appear in the proceedings of the "8th International Symposium on Radiative Corrections (RADCOR 2007)", Florence, Italy, October 1-5
We present NLO QCD results for W/Z gauge boson production with bottom quark pairs at the Tevatron including full bottom-quark mass effects. We study the impact of QCD corrections on both total cross-section and invariant mass distribution of the bottom-quark pair. Including NLO QCD corrections greatly reduces the dependence of the tree-level cross-section on the renormalization and factorization scales. We also compare our calculation to a calculation that considers massless bottom quarks and find that the bottom-quark mass effects amount to about 8-10% of the total NLO QCD cross-section and can impact the shape of the bottom-quark pair invariant mass distribution, in particular in the low invariant mass region.
NLO calculation of the Delta F = 2 Hamiltonians in the MSSM and phenomenological analysis of the B - Bbar mixing
我们给出了对MSSM强相互作用区中Delta F = 2哈密顿量Wilson系数的非线性光学修正，这是中性介子振荡的原因。这种修正，结合Delta F = 2算符的NLO异常维度矩阵和在晶格上计算的相应强子矩阵元，首次允许对与介子振荡相关的可观测量进行完整的NLO唯象分析。我们提出了在B_d - B_d棒扇区中的初步结果.
我们提出了一个实施的下一个领先的顺序强子生产的W玻色子与一对大质量的底夸克的框架中的POWHEG，一种方法，一贯接口NLO QCD计算与淋浴蒙特卡罗发电机。这个过程已经实现了使用POWHEG BOX，一个自动化的计算机代码，系统地适用于POWHEG方法的非线性光学QCD计算。在W玻色子衰变成轻子的自旋关联已被考虑使用标准的近似技术。我们目前的唯象结果为W b bbar-> l nu b bbar生产，在Tevatron和LHC，通过淋浴的POWHEG结果与PYTHIA和HERWIG，我们讨论了两个不同的淋浴蒙特卡罗程序的输出。
I summarize phenomenological LHC13 studies of the effect of dimension six effective operators on the inclusive cross section and differential distributions for the t-channel single top process at NLO in QCD.
We study tetraquark resonances with lattice QCD potentials computed for a static bbar bbar pair in the presence of two lighter quarks u d, the Born-Oppenheimer approximation and the emergent wave method. As a proof of concept we focus on the system with isospin I = 0, but consider different relative angular momenta l of the heavy quarks bbar bbar. For l=0 a bound state has already been predicted with quantum numbers I(JP) = 0(1+). Exploring various angular momenta we now compute the phase shifts and search for S and T matrix poles in the second Riemann sheet. We predict a tetraquark resonance …
The FMNRxPYTHIA interface for Heavy Quark production at HERA
本文介绍了一种基于FMNR程序与PYTHIA接口计算量子色动力学（QCD）中次主导级（NLO）重味可见能级截面的方法。它使用FMNR提供的夸克水平的NLO预测，并使用统计约化程序（REDSTAT），允许链接到PYTHIA 6.2，从那里获得完整的强子碎裂和衰变链的描述。该方法适用于在HERA的ep -> b bbar X -> D* mu X和mu+ mu- X终态。在可见光和b夸克水平上的数据和非线性光学截面的比较被发现是一致的。
We calculate the next-to-leading order (NLO) quantum chromodynamics (QCD) corrections to inclusive processes $W^+\to J/ψ(η_c)+c+\bar{s}+X$ and $W^+\to B_c(B_c^{*})+b+\bar{s}+X$ in the framework of nonrelativistic QCD (NRQCD) factorization formalism. Result indicates that the NLO corrections are significant, and the uncertainties in theoretical predictions with NLO corrections are greatly reduced. The charmonium and $B_c$ meson yielding rates at the Large Hadron Collider (LHC) are given.
In this work we investigate the NLO QCD+EW corrections to the top quark pair production and their effects on the spin correlation coefficients and asymmetries at fixed-order top quark pair production and LO decay in the dilepton channel, within the narrow-width approximation. The spin correlations are implicitly measured through the lepton kinematics. Moreover we study the EW effects to the leptonic differential distributions. We find that the EW corrections to the $t \bar t$ production are within the NLO QCD theoretical uncertainties for the spin correlation coefficients and the leptonic asym…
We report on state-of-the-art theoretical predictions for $pp\to t\bar{t}b\bar{b}$ including full off-shell effects in the di-lepton decay channel at NLO QCD accuracy. We briefly discuss the impact of NLO QCD corrections on differential distributions and also asses theoretical uncertainties from scale and PDF dependence. Furthermore, we propose a simple kinematic reconstruction in order to distinguish $b$ jets originating from top-quark decays from arising from gluon splittings.
We review the recent developments of the QCD shockwave approach at Next-to-Leading Order. The general method of this effective action is sketched, and illustrated by the case of diffractive processes.
In this paper we calculate the next-to-leading order (NLO) QCD $[{\cal O}(α_s α^3)]$ and electroweak (EW) $[{\cal O}(α^4)]$ corrections to the $WWW$ production at the LHC and deal with the subsequent leptonic decays from $W$ bosons by adopting an improved narrow-width approximation which takes into account the spin correlation and finite-width effects. The NLO QCD correction from the real jet radiation is discussed, which significantly enhances the production rate, particularly in the high-energy region. We also provide the integrated cross section for the $WWW$ production and various kinemati…
The trace amplitude method (TAM) provides us a straightforward way to calculate the helicity amplitudes with massive fermions analytically. In this work, we review the basic idea of this method, and then discuss how it can be applied to next-to-leading order (NLO) quantum chromodynamics (QCD) calculations, which has not been explored before. By analyzing the singularity structures of both virtual and real corrections, we show that the TAM can be generalized to NLO QCD calculations straightforwardly, the only caution is that the unitarity should be guaranteed. We also present a simple example t…
本文介绍了在克拉科夫IFJ PAN建立一个完整的NLO级部分子簇射蒙特卡罗程序的计划。讨论了四个问题：（1）将标准的包含共线分解扩展为一个新的完全排他的方案;（2）在新方案中重建LO Parton Shower;（3）将排他的NLO修正包含到硬过程中;（4）将排他的NLO修正包含到演化（阶梯）部分中。
