首页/论文/2007.12704

arXiv 2007.127042020-07hep-phhep-ex

A new approach to modelling elastic and inelastic photon-initiated production at the LHC: SuperChic 4

L. A. Harland-Lang, M. Tasevsky, V. A. Khoze, M. G. Ryskin

备注：: 19 pages, 5 figures, 1 table. SF formulae updated
DOI：: 10.1140/epjc/s10052-020-08455-0

英文摘要：

We present the results of the new SuperChic 4 Monte Carlo implementation of photon-initiated production in proton-proton collisions, considering as a first example the case of lepton pair production. This is based on the structure function calculation of the underlying process, and focusses on a complete account of the various contributing channels, including the case where a rapidity gap veto is imposed. We provide a careful treatment of the contributions where either (single dissociation), both (double dissociation) or neither (elastic) proton interacts inelastically and dissociates, and interface our results to Pythia for showering and hadronization. The particle decay distribution from dissociation system, as well the survival probability for no additional proton-proton interactions, are both fully accounted for; these are essential for comparing to data where a rapidity gap veto is applied. We present detailed results for the impact of the veto requirement on the differential cross section, compare to and find good agreement with ATLAS 7 TeV data on semi-exclusive production, and provide a new precise evaluation of the background from semi-exclusive lepton pair production to SUSY particle production in compressed mass scenarios, which is found to be low.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

阅读原文

阅读 PDF ↗

arXiv 页面 ↗HTML 原文 ↗

本文内容

英文摘要相关论文

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

继续探索

相关论文

Exclusive LHC physics with heavy ions: SuperChic 3

We present results of the updated SuperChic 3 Monte Carlo event generator for central exclusive production. This extends the previous treatment of proton-proton collisions to include heavy ion (pA and AA) beams, for both photon and QCD-initiated production, the first time such a unified treatment of exclusive processes has been presented in a single generator. To achieve this we have developed a theory of the gap survival factor in heavy ion collisions, which allows us to derive some straightforward results about the $A$ scaling of the corresponding cross sections. We compare against the recen…

2019-03-11hep-exhep-ph

Exclusive physics at the LHC with SuperChic 2

We present a range of physics results for central exclusive production processes at the LHC, using the new SuperChic 2 Monte Carlo event generator. This includes significant theoretical improvements and updates, most importantly a fully differential treatment of the soft survival factor, as well as a greater number of generated processes. We provide an overview of the latest theoretical framework, and consider in detail a selection of final states, namely exclusive 2 and 3 jets, photoproduced vector mesons, two-photon initiated muon and $W$ boson pairs and heavy $χ_{c,b}$ quarkonia.

2016-02-04hep-ph

LHC光子发起产生中对tau $g-2$的更高精度约束：强子解离与软存活效应的完整考量

Higher precision constraints on the tau $g-2$ in LHC photon-initiated production: a full account of hadron dissociation and soft survival effects

首次在光子发起$τ$对产生中完整考量强子解离与软存活效应对非零反常磁矩和电偶极矩的影响，发现当前可忽略但未来需重视，并已在SuperChic生成器中公开计算。

2024-10-14hep-exhep-ph

Heavy Quark Initiated Contributions to Deep Inelastic Structure Functions

We present O(alpha_s^1) corrections to deep inelastic scattering amplitudes on massive quarks obtained within the scheme of Aivazis, Collins, Olness and Tung (ACOT). After identifying the correct subtraction term the convergence of these contributions towards the analogous coefficient functions for massless quarks, obtained within the modified minimal subtraction scheme (MSbar), is demonstrated. Furthermore, the quantitative relevance of the contributions to neutral current (NC) and charged current (CC) structure functions is investigated for several choices of the factorization scale.

1998-07-17hep-ph

重夸克引发的电弱深inelastic散射系数函数通过$\mathcal{O}(α_s^2)$

Heavy-quark initiated charged-current deep-inelastic scattering coefficient functions through $\mathcal{O}(α_s^2)$

School of Physics, Shandong University（山东大学物理学院）；Tif Lab, Dipartimento di Fisica, Universit‘a di Milano and INFN, Sezione di Milano（米兰大学物理系蒂夫实验室及意大利国家核物理研究所米兰分部）

本文通过$\mathcal{O}(α_s^2)$计算重夸克引发的电弱深inelastic散射系数函数，采用切割方法求解主积分微分方程，并在脱耦方案下实现变量味数方案的应用。

2026-01-06hep-ph

A new calculation of semi-exclusive axion-like particle production at the LHC

We present a new calculation of axion-like particle (ALP) production in the semi-exclusive photon-initiated (PI) channel, that is either with intact outgoing protons or rapidity gaps present in the final state, and with no colour flow between the colliding LHC protons. This is the first full treatment of this process, accounting for both the possibility of proton dissociation and the survival factor probability of no additional proton-proton interactions, including its kinematic and process dependence. We present the expected event yields in the case that either one or both protons are require…

2023-02-22hep-exhep-ph

更多相关论文收起更多论文

Modelling $W^+ W^-$ production with rapidity gaps at the LHC

We present a new calculation of $W^+ W^-$ production in the semi-exclusive channel, that is either with intact outgoing protons or rapidity gaps present in the final state, and with no colour flow between the colliding protons. This study provides the first complete prediction of the $W^+ W^-$ semi-exclusive cross section, as well as the breakdown between elastic and proton dissociative channels. It combines the structure function calculation for a precise modelling of the region of low momentum transfers with a parton-level calculation in the region of high momentum transfers. The survival fa…

2022-01-20hep-exhep-ph

超周边重离子碰撞中重合粒子产生的建模

Modelling Coincident Particle Production in Ultraperipheral Heavy Ion Collisions

本文针对超周边重离子碰撞中的重合粒子产生进行建模，首次给出与μ子对产生相关联的ρ⁰介子产生的详细微分预测，并公开于SuperChic生成器，同时探讨了重合双光子产生及对排他性否决的影响。

2025-06-23hep-exhep-phnucl-ex

CT14QED PDFs from Isolated Photon Production in Deep Inelastic Scattering

We describe the implementation of Quantum Electrodynamic (QED) evolution at Leading Order (LO) along with Quantum Chromodynamic (QCD) evolution at Next-to-Leading Order (NLO) in the CTEQ-TEA Global analysis package. The inelastic contribution to the photon Parton Distribution Function (PDF) is described by a two-parameter ansatz, coming from radiation off the valence quarks, and based on the CT14 NLO PDFs. Setting the two parameters to be equal allows us to completely specify the inelastic photon PDF in terms of the inelastic momentum fraction carried by the photon, $p_0^γ$, at the initial sca…

2016-06-13hep-ph

Azimuthal Dependence of the Heavy Quark Initiated Contributions to DIS

We analyze the azimuthal dependence of the heavy-quark-initiated contributions to the lepton-nucleon deep inelastic scattering (DIS). First we derive the relations between the parton level semi-inclusive structure functions and the helicity $γ^{*}Q$ cross sections in the case of arbitrary values of the heavy quark mass. Then the azimuth-dependent ${\cal O}(α_{s})$ lepton-quark DIS is calculated in the helicity basis. Finally, we investigate numerically the properties of the $\cosϕ$ and $\cos2ϕ$ distributions caused by the photon-quark scattering (QS) contribution. It turns out that, contrary t…

2007-01-15hep-ph

Ad Lucem: QED Parton Distribution Functions in the MMHT Framework

We present the MMHT2015qed PDF set, resulting from the inclusion of QED corrections to the existing set of MMHT Parton Distribution Functions (PDFs), and which contain the photon PDF of the proton. Adopting an input distribution from the LUXqed formulation, we discuss our methods of including QED effects for the full, coupled DGLAP evolution of all partons with QED at $\mathcal{O}(α)$, $\mathcal{O}(αα_{S})$, $\mathcal{O}(α^2)$. While we find consistency for the photon PDF of the proton with other recent sets, building on this we also present a set of QED corrected neutron PDFs and provide the …

2021-05-07hep-exhep-ph

Dynamic colour screening in diffractive deep inelastic scattering

We present a novel Monte-Carlo implementation of dynamic colour screening via multiple exchanges of semi-soft gluons as a basic QCD mechanism to understand diffractive electron-proton scattering at the HERA collider. Based on the kinematics of individual events in the standard QCD description of deep inelastic scattering at the parton level, which at low $x$ is dominantly gluon-initiated, the probability is evaluated for additional exchanges of softer gluons resulting in an overall colour singlet exchange leading to a forward proton and a rapidity gap as the characteristic observables for diff…

2016-05-19hep-ph

Determination of collinear and TMD photon densities using the Parton Branching method

We present the first determination of transverse momentum dependent (TMD) photon densities with the Parton Branching method. The photon distribution is generated perturbatively without intrinsic photon component. The input parameters for quarks and gluons are determined from fits to precision measurements of deep inelastic scattering cross sections at HERA. The TMD densities are used to predict the mass and transverse momentum spectra of very high mass lepton pairs from both Drell-Yan production and Photon-Initiated lepton processes at the LHC.

2021-02-02hep-ph

Single-inclusive jet production in electron-nucleon collisions through next-to-next-to-leading order in perturbative QCD

We compute the ${\cal O}(α^2α_s^2)$ perturbative corrections to inclusive jet production in electron-nucleon collisions. This process is of particular interest to the physics program of a future Electron Ion Collider (EIC). We include all relevant partonic processes, including deep-inelastic scattering contributions, photon-initiated corrections, and parton-parton scattering terms that first appear at this order. Upon integration over the final-state hadronic phase space we validate our results for the deep-inelastic corrections against the known next-to-next-to-leading order (NNLO) structure …

2016-10-26hep-phnucl-th

极化质子-质子和轻子-质子碰撞中喷注内π介子产生的柯林斯效应

Collins effect in pion-in-jet production in polarized $pp$ and $ep$ collisions

Jefferson Lab（杰斐逊实验室）

研究极化质子-质子和轻子-质子碰撞中喷注内π介子产生的柯林斯方位角不对称性，采用混合横向动量依赖方法，利用相关数据提取函数，给出电子-离子对撞机运动学预测，有助于清晰获取横向极化分布。

2026-07-09hep-exhep-phnucl-th

Azimuthal Asymmetries in DIS as a Probe of Intrinsic Charm Content of the Proton

We calculate the azimuthal dependence of the heavy-quark-initiated ${\cal O}(α_{s})$ contributions to the lepton-nucleon deep inelastic scattering (DIS). It is shown that, contrary to the photon-gluon fusion (GF) component, the photon-quark scattering (QS) mechanism is practically $\cos2ϕ$-independent. We investigate the possibility to discriminate experimentally between the GF and QS contributions using their strongly different azimuthal distributions. Our analysis shows that the GF and QS predictions for the azimuthal $\cos2ϕ$ asymmetry are quantitatively well defined in the fixed flavor num…

2007-01-10hep-ph

Production of $e^{+} e^{-}$ in proton-lead collision: photon-photon fusion

We analyze the photon-initiated processes for production of $ e ^ + e ^- $ pairs in proton-nucleus collisions at LHC energy, taking into account both elastic processes and proton dissociations in the low-mass region (LMR) and intermediate-mass region (IMR) as defined by the ALICE collaboration. The calculations are performed within the $k_{\rm T}$-factorisation approach, including transverse momenta of intermediate photons. We discuss several differential distributions in invariant mass of both the leptons $M_{ll}$, pair rapidity $Y_{ll}$ and transverse momenta of the lepton pair $p_{t,ll}$. I…

2022-08-24hep-ph

极化 $\ell p$ 碰撞中喷注内介子产生的 Collins 不对称性在 EIC 的研究

Collins asymmetries for pion-in-jet production in polarized $\ell p$ collisions at the EIC

Università di Cagliari（卡利亚里大学）；INFN, Sezione di Cagliari（意大利国家核物理研究所卡利亚里分部）；Jefferson Lab（杰斐逊实验室）

本文采用简化横向动量依赖方法，计算极化轻子-质子碰撞中喷注内介子产生的 Collins 方位角不对称性，为电子-离子对撞机运动学提供预言，并验证 Collins 函数的普适性和 TMD 因子化。

2026-05-25hep-ph