LHC上Higgs至bottom quark全NNLO QCD过程的精确计算及其影响

26 浏览量更新于2024-09-05 收藏 608KB PDF 举报

在"在完整NNLO QCD中的大型强子对撞机上希格斯玻色子衰变为底部夸克的关联产生"这篇研究论文中，作者探讨了在高能粒子对撞实验，如大型强子对撞机(LHC)中，标准模型中希格斯玻色子(Higgs boson)与W±或Z玻色子共同产生的过程，并特别关注其衰变为底部夸克(Bottom quark)的特性。该研究的焦点在于提供一个高度精确的计算，即包括次顶阶量子色动力学(QCD)辐射校正的计算，达到了Next-to-Next-to-Leading Order (NNLO)的水平。作者们不仅计算了这种过程的生产截面，即事件发生的概率，而且还考虑了希格斯玻色子本身的衰变率。他们的工作不仅考虑了矢量玻色子W±/Z的轻子衰变的自旋相关性，还包含了它们的有限宽度效应，这些都是实际物理过程中不可忽视的细节。为了确保实验结果的可靠性，研究者采用了LHC实验中常见的动量分布边界条件。结果显示，完整的NNLO QCD校正对于这类事件的横截面有显著影响，可能会降低它，同时也会改变事件分布的形态特征。这对于理论家来说是至关重要的，因为这关系到能否精确地预测并解释LHC实验的数据，从而验证或排除物理模型。这篇论文的发表日期为2018年，接收、修订和接受的时间也有所记录，表明研究过程的严谨性和科学价值。编辑为G.F.Giudice。这项研究为理解希格斯玻色子的性质及其在高能物理实验中的行为提供了关键的理论支持，对于粒子物理学的标准模型和新物理搜索具有重要意义。

Physics Letters B 780 (2018) 346–351

Contents lists available at ScienceDirect

Physics Letters B

www.elsevier.com/locate/physletb

Associated production of a Higgs boson decaying into bottom quarks at

the LHC in full NNLO QCD

Giancarlo Ferrera

a,∗

, Gábor Somogyi

, Francesco Tramontano

Dipartimento di Fisica, Università di Milano and INFN, Sezione di Milano, I-20133 Milan, Italy

MTA-DE Particle Physics Research Group, H-4010 Debrecen, PO Box 105, Hungary

Dipartimento di Fisica, Università di Napoli and INFN, Sezione di Napoli, I-80126 Naples, Italy

a r t i c l e i n f o a b s t r a c t

Article history:

Received

15 September 2017

Received

in revised form 24 January 2018

Accepted

6 March 2018

Available

online 12 March 2018

Editor:

G.F. Giudice

We consider the production of a Standard Model Higgs boson decaying to bottom quarks in association

with a vector boson W

/Z in hadron collisions. We present a fully exclusive calculation of QCD radiative

corrections both for the production cross section and for the Higgs boson decay rate up to next-to-

next-to-leading

order (NNLO) accuracy. Our calculation also includes the leptonic decay of the vector

boson with ﬁnite-width effects and spin correlations. We consider typical kinematical cuts applied in

the experimental analyses at the Large Hadron Collider (LHC) and we ﬁnd that the full NNLO QCD

corrections signiﬁcantly decrease the accepted cross section and have a substantial impact on the shape

of distributions. We point out that these additional effects are essential to obtain precise theoretical

predictions to be compared with the LHC data.

(http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP

The discovery of the long sought Higgs boson (H)[1,2]by

the ATLAS and CMS Collaborations at the Large Hadron Collider

(LHC) [3,4]paved the way for the experimental investigation of

the electroweak (EW) symmetry breaking mechanism and, in par-

ticular,

for the measurements of the Higgs boson couplings to

the Standard Model (SM) particles. In this respect the increasing

amount of precise experimental data collected at the LHC demands

a corresponding improvement of theoretical predictions.

One

of the main production mechanisms of the SM Higgs bo-

son

at hadron colliders is the associated production with a vector

boson (V = W

, Z ). This process offers the unique opportunity to

study both the Higgs boson coupling to massive gauge bosons and

to bottom (b) quarks via the decay H → b

A direct search for the SM Higgs boson through associated

VH production and H → b

b decay has been carried out at the

LHC at a centre–of–mass energy of

√

s = 7/8TeV[5,6] and at

√

s = 13 TeV [7,8]. The ATLAS and CMS Collaborations observed

an excess of events above the expected background with a mea-

sured

signal strength relative to the SM expectation of 0.90 ±

0.18 (stat.)

+0.21

−0.19

(syst.) [7] and μ = 1.06

+0.31

−0.29

[8] respectively.

High precision theoretical predictions require detailed com-

putations

of radiative corrections for cross sections and corre-

Corresponding author.

E-mail

address: giancarlo .ferrera @mi .infn .it (G. Ferrera).

sponding distributions. The total cross section for associated VH

production

is known at next-to-next-to-leading order (NNLO) in

QCD [9–12] and next-to-leading order (NLO) in the electroweak

theory [13,14]. Fully differential calculations have been performed

in NNLO QCD for the VH production cross section, together with

the NLO QCD corrections for the Higgs boson decay rate into bot-

tom

quarks [15–18]. The fully differential H → b

b decay rate has

been computed up to NNLO in QCD [19,20] while the inclusive rate

is known up to O(α

) [21] and up to NLO in the electroweak the-

ory [22,23].

Resummation and higher order (beyond NNLO) QCD

effects have been investigated in Refs. [24–30] while the combi-

nation

of ﬁxed-order QCD calculations with parton shower Monte

Carlo algorithms has been considered in Refs. [31–33]. NLO EW ef-

fects

at fully differential level for VH production with the leptonic

decay of the vector boson have been considered in Refs. [14,34].

this letter we present the fully differential calculation of the

NNLO QCD corrections for the production cross section and for the

Higgs boson decay rate to bottom quarks, exploiting the very good

accuracy of the narrow width approximation for the Higgs boson

(

 m

). In Refs. [16,35]it was shown that, when the set of

kinematical cuts applied in the LHC analyses are considered, the

effect of QCD corrections to the Higgs boson decay process can

be large. Motivated by these ﬁndings, we extend existing calcula-

tions

on higher order QCD predictions by considering the complete

second

order terms. Together with the NNLO corrections for the

production cross section, we include the NNLO corrections to the

https://doi.org/10.1016/j.physletb.2018.03.021

0370-2693/

SCOAP

下载后可阅读完整内容，剩余5页未读，立即下载

weixin_38552292

粉丝: 6
资源: 894

LHC上Higgs至bottom quark全NNLO QCD过程的精确计算及其影响

NNLO QCD中DIS的强子态最终状态，并伴有阵雨

在大型强子对撞机上探测沉重的希格斯玻色子

关于在大型强子对撞机中检测Z + bb产生的希格斯衰变H→bb的可能性

强子对撞机ZH生产：NNLO QCD全差分计算及其影响

用希格斯玻色子对产生探测类似矢量的夸克模型

NNLO计算：关联生产希格斯玻色子与矢量玻色子

ATLAS探测器在多轻子最终状态中寻找与顶夸克对关联产生的希格斯玻色子

在两个不同帧中通过极化顶夸克衰变对带电希格斯产生的QCD分析

大型对撞机的希格斯对产量以对数精度近乎领先

稀有顶部腐烂，成为希格斯玻色子的探针

最新资源