Conveners
分会场一: TeV物理和超出标准模型新物理（一）
- 益 廖 ()
- 昊 张 ( 理论室)
- 冰 李 (山东大学)
- Xiaohu SUN (Peking University)
Interest in searches for Charged Lepton Flavor Violation (CLFV) has persisted over the past few decades, as the observation of CLFV would indicate new physics beyond the Standard Model (BSM). Several future high-luminosity lepton colliders have been proposed, which will enable CLFV searches to reach unprecedented precision. This work performs a detailed comparative study of CLFV searches at...
We present FMNLO, a framework to combine general-purpose Monte Carlo generators and fragmentation functions (FFs).
It is based on a hybrid scheme of phase-space slicing method and local subtraction method,
and accurate to next-to-leading order (NLO) in QCD.
The new framework has been interfaced to MadGraph and made publicly available in this work.
We perform a simultaneous global...
A review of Higgs property measurement from ATLAS including both the di-Higgs and single Higgs measurement.
Physics is an empirical discipline, so any theory, no matter how elegant, must be tested through experiments. The scattering amplitude, as a physical quantity, serves as a bridge between theory and experiment. With the current precision of accelerators and experiments, the leading-order calculation of tree-level amplitude is insufficient in terms of experimental precision. Therefore,...
We describe the origin of the hierarchical SM quark/lepton Yukawa couplings with the single SM Higgs doublet in an SU(8) theory, where three-generational SM fermions are non-trivially embedded.
A combination of searches for new heavy spin-1 resonances decaying into different pairings of W, Z, or Higgs bosons, as well as directly into leptons or quarks, is presented. The data sample used corresponds to 139 fb−1 of proton-proton collisions at √s = 13TeV collected during 2015–2018 with the ATLAS detector at the CERN Large Hadron Collider. Analyses selecting quark pairs (qq, bb, tt, and...
Ref. https://arxiv.org/abs/2406.01656
A combination of searches for Higgs boson decaying into a visible photon and a massless dark photon (H→γγ$_{d}$) is presented using 139 fb$^{-1}$ of proton--proton collision data at a centre-of-mass energy of √s = 13 TeV recorded by the ATLAS detector at the Large Hadron Collider. The observed (expected) 95% confidence level upper limit on the Standard...
This talk would present a combination of searches for Higgs boson pair production using the ATLAS Run2 data sets. The upper limit on the production rate at 95% confidence level(CL) is 2.9 times the Standard Model (SM) prediction, with an expected limit of 2.4 assuming no Higgs boson pair production. Constraints on the Higgs boson self-coupling...
∆L = 2 lepton number violation at the TeV scale connects 0νββ decay (intensity frontier), LHC
searches (energy frontier), and leptogenesis (cosmic frontier). I will focus on some progress on the
promising UV completions of 0νββ decay operators, which can be diagnosed with complementary
searches at the HL-LHC and HE-LHC.
Millicharged particles can be created in the atmosphere when high energy cosmic rays collide with nuclei, resulting in potentially observable signals at neutrino detectors. We analyse the resulting single scatter and multiple scatter signals at SuperK and JUNO. Searches for low energy coincident signals at JUNO will be sensitive to MCPs with masses between 2 GeV and 10 GeV with milli-charges...
We propose a new ``disappearing positron track'' channel at Belle II to search for dark matter, in which a positron that is produced at the primary interaction vertex scatters with the electromagnetic calorimeter to produce dark matter particles. Such scatterings can occur via either annihilation with atomic electrons, or the bremsstrahlung process with target nuclei. The main backgrounds are...
The case that a Z' hidden inside a Z resonance was neglected in the literature, maybe for the complicated mixing and interference effects of the nearly-degenerate system. We aimed at filling in this gap and discussed the possibility of the existence of such a system, and the possibility of searching this Z' particle at a lepton collider.
Ref. https://arxiv.org/abs/2403.02809
The observation of the electroweak production of a W boson and a photon in association with two jets, using pp collision data at the Large Hadron Collider at a centre of mass energy of √s = 13 TeV, is reported. The data were recorded by the ATLAS experiment from 2015 to 2018 and correspond to an integrated luminosity of 140 fb$^{−1}$. This process is...
Fragmentation functions (FFs) are essential non-perturbative inputs for precision calculations of hadron production cross sections in high energy scattering from first principle of QCD. They are usually extracted from global analysis on world data from single inclusive hadron production at lepton colliders, semi-inclusive DIS and pp collisions, e.g., as in recent NPC23 analysis. Future lepton...
We propose a theory to systematically construct a complete set of on-shell effective operator bases involving massive particles with any spins. The amplitude bases involving massive fields can be factorized into two charged and neutral parts under the little groups of massive particles, respectively. The complete bases of these two parts can be constructed by the Young diagrams of Lorentz...
We calculate the total cross-section and differential distribution of Higgs boson pair production and decay to $b\bar{b}\gamma\gamma$ at NLO in QCD
This talk will discuss a few recent results from diboson sector in the ATLAS experiment, focusing on novelty and impact of these results. Propects will also be breifly discussed.
The muon (−2) anomaly is a longstanding puzzle in particle physics. Both the theoretical prediction and experimental measurement are expected to be improved in the near future. It may be a signal of new physics, and tremendous amount of new physics models are proposed to explain this anomaly. However, many papers focus on the singlet and doublet vector-like lepton extended models without...
This talk presents the first comprehensive search for non-resonant Higgs boson pair (HH) production in multiple-lepton decay channels, including VVVV, VVtautau, tautautautau, yyVV, and yytautau, where V is W or Z boson. The analysis also explores decays of HH to bbZZ with the Z bosons decaying into leptons. Data is derived from proton-proton collisions at 13 TeV, captured by the ATLAS detector...
The ForwArd Search ExpeRiment (FASER,), is a recently installed detector at the LHC that can detect light, long lived particles. In this work we study the prospect of detecting light CP-even and CP-odd scalars at the FASER. We develop the general formalism for the scalar production and decay from mesons at LHC, given modified couplings of the scalars to the SM particles, as well as...
We compute low energy supernova constraints on new light particles.
We consider real Higgs triplet extension to Standard Model and match it to a non-linear effective field theory, the Higgs Effective Field Theory(HEFT). For the decoupling and non-decoupling regimes different power counting methods are adopted, the effective Lagrangians at leading order are derived. Their effects in physical observables are plotted. Later we present the parametrization of the...
The Higgs Boson plays a fundamental role in Standard Model, and the precise measurement of its mass and width is one of the most important tasks of particle physics experiments. The mass measurement benefits from the processes where Higgs Boson decays into four leptons and two photons due to their excellent mass resolution, while Higgs boson width is measured indirectly by combining the...
I will present ttW differential cross-section measurement using 140fb-1 proton-proton collision data recorded from 2015 to 2018 with the ATLAS detector at the Large Hadron Collider. The inclusive ttW production cross-section is measured to be 880+80fb, in agreement with predictions within 2 standard deviations. This result is a very important input for the ongoing ttH...
The recent observation of four-top-quark production at the ATLAS experiment in 2023 has highlighted the complexities involved in the reconstruction of heavy particles like the top quark. This process is particularly challenging due to issues such as missing momentum and the extensive permutations of jets. To address these challenges, we apply SPA-Net, a machine learning method, which...
In the high-energy limit, the massive amplitudes can be expanded in $v/E$. The power counting suggests that the term with $v^l$ corresponds to the massless amplitudes with $l$ extra Higgs bosons. Once we know the massless amplitudes, we can use this correspondence to determine the massive amplitudes, in both renormalizable theory and effective theory with spontaneouly symmetry breaking.
Photons are important particles in collider physics. They play a crucial role in Standard Model (SM) processes, Higgs decays, or any potential new interactions that beyond the Standard Model. Therefore, photon identification efficiency is indispensable for many interesting physical analyses in collider physics. This poster presents the electron extrapolation method for photon identification...
The center-of-mass energy of Circular Electron
Positron Collider (CEPC) could be upgrade to 360 GeV level
(CEPC@360GeV) after its ten-year running at 240 GeV.
Besides SM precision measurements, CEPC@360GeV also
has good potential for BSM physics searches, which is a
good complementary for hadron colliders. This paper presents
the sensitivity study of direct stau and smuon pair...
Precision measurements have played a key role in the development of particle physics. This presentation will report the latest measurement of differential cross-section of Drell-Yan $Z\gamma$ process using data collected by the ATLAS detector in run2, in particular concerning the jet activities. $Z\gamma$ production is a major background for many new physics process and $Z\gamma$ itself can...
To describes a preliminary simplified fiducial decay selection for the H to 4l channel to be used with STXS measurements in order to reduce acceptance corrections needed in the presence of BSM contributions in the H to 4l decay. The simplified fiducial decay selection is Lorentz invariant in order to have a production mode and boost independent acceptance. The reconstruction fraction as...
Ref. https://arxiv.org/abs/2404.15937
(Accepted by Frontier of Physics)
Neutral triple gauge couplings (nTGCs) are absent in the Standard Model (SM) and at the dimension-6 level in the Standard Model Effective Field Theory (SMEFT), arising first from dimension-8 operators. As such, they provide a unique window for probing new physics beyond the SM. These dimension-8 operators can be mapped...
Higgs boson couplings to second generation fermions and rare decays of the Higgs boson are an active field of study and are an important pillar to the Higgs boson physics at the LHC. This talk will present the latest results on second-generation Yukawa couplings from the ATLAS experiment. It will also include the latest results on the Higgs boson decaying to a Z boson and a photon.
Quirk particles are charged under both the Standard Model gauge group and a new confinement gauge group. The confinement scale of the new confining group is much smaller than quirk masses. Thus a TeV scale quirk can be copiously produced at the LHC and traveling with anomalous trajectories. There will be a significant amount of quirk events traveling in the forward direction. The timing...
Quantum simulation of High Energy Physics (HEP) has seen remarkable growth in recent years. Nevertheless, there is a continuous need for advancements in the overall simulation framework. In my talk, I will first motivate the critical need for quantum computing in HEP and discuss recent developments. Then I will explore the roles of gauge redundancies in simulating field theories on a quantum...
Ref: https://arxiv.org/abs/2306.00641
Results from a wide range of searches targeting different experimental signatures with and without missing transverse momentum ($^{}_{}$) are used to constrain a Two-Higgs-Doublet Model (2HDM) with an additional pseudo-scalar mediating the interaction between ordinary and dark matter (2HDM+a). The analyses use up to 139 fb$^{−1}$ of proton-proton...
A search for a heavy resonance decaying into a top quark and a W boson in proton-
proton collisions at √s = 13 TeV is presented. The data was recorded by CMS detector and correspond to an integrated luminosity of up to 138 fb−1. The analysis is performed in the lepton+jets final state, where the top quark is reconstructed from an electron or muon, missing transverse momentum and a jet...
A search for a hypothetical heavy scalar particle, $X$, decaying into a singlet scalar particle, $S$, and a Standard Model Higgs boson, $H$, using 140 fb$^{-1}$ of proton--proton collision data at the centre-of-mass energy of 13 TeV recorded with the ATLAS detector at the LHC is presented. The explored mass range is $300 \leq m_X \leq 1000$ GeV and $170 \leq m_S \leq 500$ GeV. The signature of...
A search is presented for new Higgs bosons in proton-proton (pp) collision events in which a same-sign top quark pair is produced in association with a jet, via the pp → tH/A → tt¯c and pp → tH/A → tt¯u processes. Here, H and A represent the extra scalar and pseudoscalar boson, respectively, of the second Higgs doublet in the generalized two-Higgs-doublet model (g2HDM). The search is based on...
Ref. https://arxiv.org/abs/2404.17193
A search for Higgs boson pair production via vector-boson fusion is performed in the Lorentz-boosted regime, where a Higgs boson candidate is reconstructed as a single large-radius jet, using 140 fb$^{−1}$ of proton-proton collision data at √s = 13 TeV recorded by the ATLAS detector at the Large Hadron Collider. Only Higgs boson decays into bottom quark...
Within the Standard Model, transverse single spin asymmetries in electron elastic scatterings arise only from multi-photon exchanges. Experiments at MIT-Bates, MAMI, JLab, where transversely polarized electron beams scatter off both hydrogen and nuclei targets, show surprising discrepancies from theoretical calculations based on unitary and optical theorem. Comparing with the unitary...
Recent SUSY searches in final states with light leptons or taus using 139 $\mathrm{fb}^{-1}$ of $pp$ collision data at $\sqrt{s} = 13$ TeV collected with the ATLAS detector at the Large Hadron Collider will be presented.
Both $R$-parity conserving and violating scenarios will be covered, including the direct pair production of squarks, gluinos, gauginos, higgsinos, and staus.
In general,...
This talk will present the latest search for the non-resonant production of Higgs boson pairs in the $HH\rightarrow b\bar{b}\tau^+\tau^-$ channel. The search is performed using 140 fb$^{-1}$ of proton--proton collisions at a centre-of-mass energy of $13$ TeV recorded by the ATLAS detector at the LHC. The analysis strategy is optimized to probe anomalous values of the Higgs boson self-coupling...
The future muon collider with high energy and high luminosity can be an ideal place to search for new physics. It can play as an emitter of electroweak gauge bosons and thus leads to substantial vector boson scattering (VBS) processes. In this series of works, we focus on heavy neutral lepton (HNL), Type-II and Type-III seesaw mechanisms, attempting to reveal the origin of neutrino masses...
To reveal hidden NP effects on the top of SM, it is SMEFT that provides a powerful systematic bottom-up approach to parameterize them. Among them the chirality-flip operators, which flip fermion helicities, remain poorly constrained by current experimental analyses for lack of interference with the SM amplitudes in traditional observables with leading effect starting at...
磁单极子是被大统一理论预言的基本粒子，其在解释电荷量子化,宇宙暴涨模型等问题上具有重要理论意义,但已有的在地面或者深地开展的物理实验未发现其存在的可靠证据。随着航天技术的飞速发展,深空粒子探测实验为磁单极子的搜寻提供了新的可能，但考虑到深空严峻的本底环境,在深空开展稀有物理事例搜寻需要探测器具备极佳的事例判选能力。为此,SCEP实验组提出利用感应信号以及塑料闪烁体之间的偶然符合方式在深空环境中对磁单极子进行搜寻。本报告将阐述SCEP实验组在探测系统预研过程中的模拟,实验测试等工作,并给出这套探测系统能达到预期磁单极子通量探测的灵敏度。
Search for nonresonant Higgs boson pair production in the $b\bar{b}\gamma\gamma$ final state is performed using 140 fb$^{-1}$ of proton--proton collisions at a centre-of-mass energy of 13 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. This analysis supersedes and expands upon the previous nonresonant ATLAS results in this final state based on the same data sample. The...
We present the calculation of QCD one-loop correction for tWb production. In particular, due to the well-known interference between tWb and top pair production, we introduce a new method to subtract the anti-top resonance at loop level. This method is implemented by extracting the leading-order (LO) of the resonance expansion, employing the idea of effective theory.
Serval summary studies of the ATLAS Run 2 SUSY searches at the LHC are presented in this talk, including the recent results on the constraints from the searches performed by the ATLAS Collaboration on the 19-parameter phenomenological minimal supersymmetric standard model (pMSSM-19), statistical combinations of searches for the SUSY particles in various decay channels, and the...
We systematically investigate dark matter direct detection in effective field theories, including nuclear recoil signal, electron recoil signal, and Migdal effects.
The Standard Model extended with a complex or real singlet scalar can admit a strong first order electroweak phase transition as needed for electroweak baryogenesis. The real singlet component that mixes with the Standard Model Higgs boson leads to the possibility of di-Higgs and di-boson final states in pp collisions. The complex component can provide a dark matter (DM) candidate that leads...
This study focuses on quantum simulation of the sphaleron configurations in a 1+1-dimensional field theory model, achieved by introducing linear additional terms into the action of the $O(3)$ nonlinear sigma-model. We discretize the Lagrangian of the aforementioned (1+1)D model and construct a Hamiltonian representation based on unitary quantum gate forms, enabling the construction of...
One kind of the large logarithm at subleading power appears in the loop-induced processes. In the prosses of Higgs boson dedcay H -> γγ via a bottom quark loop, we have developed a method with soft-collinear effective theory to extract and resum these large logarithms.
In 2023, the Fermilab Muon g-2 collaboration reported the Run-2/3 results, achieving a precision measurement of the muon's anomalous magnetic moment at 0.20 ppm. The analysis for the combined dataset from Run-4/5/6 is nearing completion, aiming to surpass previous precision levels. The slow term effects, which have been identified as significant contributors to systematic uncertainties in...
For loops with UV divergences, finite physical results obtained via infinity − infinity mean the physical transition amplitudes of loops are not mathematically well-defined. In this talk, a new method of UV-free scheme will be introduced to derive loop results without UV divergences. It provides a new perspective to the hierarchy problem of Higgs mass without fine-tuning within the Standard...
按SU(5)大统一模型[1]、[2]，对称性破缺方式是SU（5）→SU（3）×SU(2)×U(1)→U(1)。在强子内部有近似的SU(3)×U(1)定域对称性，强子作为非拓扑孤粒子存在；在强子中的夸克与胶子具有近似已知夸克与胶子的性质；在强子外部，夸克具有整数电荷，只有U(1)定域对称性。强子内部夸克与胶子的质量远小于强子外部夸克与胶子的质量，自由夸克与胶子能够存在，但将很快衰变为强子和轻子；轻子进入强子中的质量显著大于轻子在强子外部时的质量，因此轻子不能存在于强子内部。按本模型，没有夸克禁闭问题，自然地解释了宇宙中正反重子不对称现象，μ子磁矩反常（比标准模型预言的更大），Xe原子的电子受到的反常作用，B介子的反常衰变。最近超出标准模型的一个新实验是
Σ^+→p^++μ^-+μ^+, ...
带电轻子味道破坏（cLFV）过程在标准模型内受中微子质量影响被严重压低，而在多种新物理模型中却可能被提高到实验可观测的量级，因此是新物理模型研究的重要信号之一。考虑到电子缪子相互作用的独特优势，我们研究了未来电子缪子对撞机上由额外引入的中性规范玻色子$Z$'传播的cLFV过程。基于蒙特卡洛计算和检测器快速模拟，我们对cLFV信号和可能的本底的特征进行了研究，并给出了信号在90%置信水平下的截面上限和对应耦合常数$\lambda_{e\mu}$和$\lambda_{e\tau}$的结果。对比当前实验上限与未来实验预期，电子缪子对撞在含陶子末态的耦合常数灵敏度上表现出显著优势。与此同时，轻子对撞实验还可对当前缺乏研究的$\lambda_{\mu\mu}×\lambda_{e\mu}$过程进行测量，且具备较好的灵敏度。
在高能物理中，散射振幅连结着理论与实验，扮演着极重要的角色。如何超越传统费曼图，建立新的原理和方法，更好地计算和理解振幅，是振幅现代研究的核心问题之一。在这个报告中，我将给出一种逆用无质量粒子的软行为来构造树图振幅的新方法。这是一种在壳方法，避免了费曼规则的规范冗余度。相比其他逆用软行为的方法，这种新方法不需要假设软因子为已知，只假设软行为的普遍性，因而增大了方法的适用范围，同时也避免了振幅与软因子谁决定谁的逻辑混乱。我将介绍如何用这种方法构造Yang-Mills-scalar与Yang-Mills树图振幅，给出任意点振幅的普遍表达式，并通过double copy结构推广到含引力子的情况。同时，我也会讨论将这种方法推广到有效理论，构造含高阶导数相互作用的胶子振幅，及非线性sigma模型等标量有效理论的振幅。
费曼积分是高能物理精确理论预言的基本计算工具。传统高圈多外线费曼积分的解析计算非常困难。运用动量 twistor 变量和多对数函数字母表新搜索算法，我们在高圈多外线费曼积分解析计算领域取得了突破。我们将介绍维数正规化下双圈六点费曼积分的解析结果，该成果可用于 4 jets 产生过程的 NNLO 截面计算。这一发展也是迄今为止维数正规化下,含标度最多的双圈费曼积分解析结果。
