We show how the 2-Higgs Doublet Model (2HDM) Type-I can explain some excesses recently seen at the Large Hadron Collider (LHC) in <italic>&#947;&#947;</italic> and <math altimg='si29.svg'><mrow><msup><mi>&#964;</mi><mo>+</mo></msup><msup><mi>&#964;</mi><mo>&#8722;</mo></msup></mrow></math> final states in turn matching Large Electron Positron (LEP) data in <math altimg='si30.svg'><mrow><mi>b</mi><mover accent='true'><mi>b</mi><mo>&#175;</mo></mover></mrow></math> signatures, all anomalies residing around 95&#8239;GeV. The explanation to such anomalous data is found in the aforementioned scenario when in inverted mass hierarchy, in two configurations: i) when the lightest CP-even Higgs state is alone capable of reproducing the excesses; ii) when a combination of such a state and the CP-odd Higgs boson is able to do so. To test further this scenario, we present some Benchmark Points (BPs) of it amenable to phenomenological investigation.

India

Akshat Khanna

United Kingdom

Sweden

Stefano Moretti

Agnivo Sarkar

Explaining 95 GeV anomalies in the 2-Higgs doublet model type-I

The precise measurement of the top-Higgs coupling is crucial in particle physics, offering insights into potential new physics Beyond the Standard Model (BSM) carrying $$ \mathcal{CP} $$ Violation (CPV) effects. In this paper, we explore the $$ \mathcal{CP} $$ properties of a Higgs boson coupling with a top quark pair, focusing on events where the Higgs state decays into a pair of $\textit{b}$-quarks and the top-antitop system decays leptonically. The novelty of our analysis resides in the exploitation of two conditional Deep Learning (DL) networks: a Multi-Layer Perceptron (MLP) and a Graph Convolution Network (GCN). These models are trained for selected CPV phase values and then used to interpolate all possible values ranging from 0 to $\textit{π}$/2. This enables a comprehensive assessment of sensitivity across all $$ \mathcal{CP} $$ phase values, thereby streamlining the process as the models are trained only once. Notably, the conditional GCN exhibits superior performance over the conditional MLP, owing to the nature of graph-based Neural Network (NN) structures. Specifically, for Higgs top coupling modifier set to 1, with $$ \sqrt{s} $$ = 13.6 TeV and integrated luminosity of 3 ab GCN excludes the $$ \mathcal{CP} $$ phase larger than 5$\textit{°}$ at 95$\textit{.}$4% Confidence Level (C.L). Our Machine Learning (ML) informed findings indicate that assessment of the $$ \mathcal{CP} $$ properties of the Higgs coupling to the $$ t\overline{t} $$ pair can be within reach of the High Luminosity Large Hadron Collider (HL-LHC), quantitatively surpassing the sensitivity of more traditional approaches.

Germany

Waleed Esmail

Japan

A. Hammad

South Korea

Adil Jueid

Boosting probes of $$ \mathcal{CP} $$ violation in the top Yukawa coupling with Deep Learning

Under the assumption that the various evidences of a ‘95 GeV’ excess, seen in data at the Large Electron Positron (LEP) collider as well as the Large Hadron Collider (LHC), correspond to actual signals of new physics Beyond the Standard Model (BSM), we characterise the underlying particle explaining these anomalies in terms of its Charge/Parity (CP) quantum numbers. In doing so, we use <italic>&#967;</italic> 2 fits to test the CP-even (scalar) and CP-odd (pseudoscalar) hypotheses and superpositions of these, thus under the assumption of a spin-0 resonance. This is done through the exploitation of <math altimg='si3.svg'><mrow><msup><mi>&#964;</mi><mo>+</mo></msup><msup><mi>&#964;</mi><mo>&#8722;</mo></msup></mrow></math> decays, in both their fully hadronic and semi-leptonic modes, in a model-independent way, so that our approach enables one to test a variety of BSM hypotheses, having proven here that the High-Luminosity LHC (HL-LHC) will be in a position to disentangle the CP nature of such a new particle within <math altimg='si9.svg'><mrow><mo>&#177;</mo><mo>(</mo><mn>0.27</mn><mo linebreak='goodbreak'>&#8722;</mo><mn>0.47</mn><mo>)</mo></mrow></math> radians of the true hypothesis at 90&#8201;% Confidence Level (CL), depending on the assumed background systematics.

Tanmoy Mondal

Prasenjit Sanyal

On the CP Nature of the `95 GeV' Anomalies

In this study, we propose the interpretation of a 650 GeV excess observed at the Large Hadron Collider (LHC) by the CMS Collaboration in terms of the production of a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>C</mi><mi>P</mi></mrow></math>-odd (or pseudoscalar) Higgs boson <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>A</mi></math>, with mass around 650 GeV, decaying into the Standard Model (SM)-like Higgs state <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>h</mi><mn>125</mn></msub></math> (in turn decaying into <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi><mi>γ</mi></math>) and a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi></math> boson (in turn decaying into <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover></math>), within a three-Higgs doublet model (3HDM) featuring two active and one inert doublet, known as the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="normal">I</mi><mo stretchy="false">(</mo><mrow><mn>1</mn><mo>+</mo><mn>2</mn></mrow><mo stretchy="false">)</mo><mi>HDM</mi></mrow></math>. This theoretical structure features a spectrum with both the SM-like Higgs boson (with a 125 GeV mass) and a lighter <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math>-even (or scalar) Higgs state with mass around 95 GeV, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>h</mi><mn>95</mn></msub></math>, which is present in this scenario for the purpose of simultaneously explaining anomalies seen in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi><mi>γ</mi></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>τ</mi><mo>+</mo></msup><msup><mi>τ</mi><mo>−</mo></msup></math> final states in searches for additional light Higgs states at the Large Electron-Positron collider and LHC itself. It should be noted that, in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="normal">I</mi><mo stretchy="false">(</mo><mrow><mn>1</mn><mo>+</mo><mn>2</mn></mrow><mo stretchy="false">)</mo><mi>HDM</mi></mrow></math>, the inert sector presents loop-induced enhancements to the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>h</mi><mn>95</mn></msub><mo stretchy="false">→</mo><mi>γ</mi><mi>γ</mi></math> width via additional scalar charged states, providing a viable mechanism to explain, in particular, the observed (and most significant) diphoton excess at 95 GeV. Taking into account both experimental and theoretical constraints, our results can not only explain the aforementioned anomalies (possibly, aside from the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>τ</mi><mo>+</mo></msup><msup><mi>τ</mi><mo>−</mo></msup></math>, which is the most marginal one) but also predict, as collateral signals, resonant production of the same <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math>-odd scalar <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>A</mi></math> followed by the decays: (i) <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>A</mi><mo stretchy="false">→</mo><msub><mi>h</mi><mn>95</mn></msub><mi>Z</mi></math>, leading to the same <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi><mi>γ</mi><mi>b</mi><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover></math> final state displaying the original 650 GeV anomaly and (ii) <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>A</mi><mo stretchy="false">→</mo><mi>t</mi><mover accent="true"><mi>t</mi><mo stretchy="false">¯</mo></mover></math>, leading to a well-known and studied signature. Both of these signals are potentially explorable at Run 3 of the LHC and most possibly so at the High-Luminosity LHC, while being consistent with current data at a significance level of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2.5</mn><mi>σ</mi></math>.

Morocco

Ayoub Hmissou

Larbi Rahili

Could the 650 GeV excess be a pseudoscalar of a three-Higgs-doublet model?

We study resonant production of pairs of Standard Model (SM-)like Higgs bosons, in the presence of new neutral Higgs states together with new colored scalars (stops or sbottoms) in loops within the Next-to-Minimal Supersymmetric Standard Model. This is used as a test case to prove that the Large Hadron Collider has sensitivity to a variety of effects stemming from interferences between resonant (heavy) Higgs diagrams and/or among these and nonresonant topologies involving loops of both tops and stops. These effects can alter significantly the naive description of individual <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>s</mi></mrow></math>-channel Breit-Wigner resonances, leading to distortions of the latter, which, on the one hand, may mask their presence but, on the other hand, could enable one to extract features of the underlying new physics scenario. This last aspect is made possible through a decomposition of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>g</mi><mi>g</mi><mo stretchy="false">→</mo><mi>h</mi><mi>h</mi></math> signal process into all its amplitude components, each of which has a well-defined coupling structure. Ultimately, such effects can be traced back to the relevant Feynman diagrams and can enable a detailed interpretation of this process. To illustrate this, we introduce various benchmark points that exhibit potentially observable features during the current and/or upcoming runs of the LHC in one or more of the three customary di-Higgs decay channels: <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover><mi>b</mi><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover><msup><mi>τ</mi><mo>+</mo></msup><msup><mi>τ</mi><mo>−</mo></msup></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover><mi>γ</mi><mi>γ</mi></math>.

Italy

Luca Panizzi

Jörgen Sjölin

Harri Waltari

Deconstructing resonant Higgs boson pair production at the LHC: Effects of colored and neutral scalars in the NMSSM test case

This work investigates the discovery potential for singly produced vectorlike quarks (VLQs) <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Q</mi><mo>=</mo><mo>+</mo><mn>2</mn><mo>/</mo><mn>3</mn><mi>e</mi></math>) and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Y</mi></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Q</mi><mo>=</mo><mo>−</mo><mn>4</mn><mo>/</mo><mn>3</mn><mi>e</mi></math>) decaying to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi><mi>b</mi></math> at future <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>μ</mi><mi>p</mi></math> colliders with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>5.29</mn></math>, 6.48, and 9.16 TeV, analyzing both leptonic and hadronic <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi></math> decay channels through detailed detector simulations. The hadronic channel demonstrates superior sensitivity, enabling <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>5</mn><mi>σ</mi></math> discovery up to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>T</mi></msub><mo>=</mo><mn>3750</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>Y</mi></msub><mo>=</mo><mn>4100</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>) at 9.16 TeV with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>100</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>, while exclusion limits reach <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>T</mi></msub><mo>=</mo><mn>4500</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>g</mi><mo>*</mo></msup><mo>≥</mo><mn>0.06</mn></math>) and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>Y</mi></msub><mo>=</mo><mn>4800</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>κ</mi><mi>Y</mi></msub><mo>≥</mo><mn>0.04</mn></math>)—significantly beyond LHC capabilities. At 5.29 TeV, discovery regions cover <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>g</mi><mo>*</mo></msup><mo>∈</mo><mo stretchy="false">[</mo><mn>0.15</mn><mo>,</mo><mn>0.5</mn><mo stretchy="false">]</mo></math> for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>T</mi></msub><mo>∈</mo><mo stretchy="false">[</mo><mn>1500</mn><mo>,</mo><mn>2520</mn><mo stretchy="false">]</mo><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>κ</mi><mi>Y</mi></msub><mo>∈</mo><mo stretchy="false">[</mo><mn>0.12</mn><mo>,</mo><mn>0.5</mn><mo stretchy="false">]</mo></math> for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>Y</mi></msub><mo>∈</mo><mo stretchy="false">[</mo><mn>1700</mn><mo>,</mo><mn>2700</mn><mo stretchy="false">]</mo><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>, with exclusions extending to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>T</mi></msub><mo>=</mo><mn>2750</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>Y</mi></msub><mo>=</mo><mn>3020</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>. These results, obtained within a simplified two-parameter framework (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mrow><mi>T</mi><mo>/</mo><mi>Y</mi></mrow></msub></math> and electroweak couplings <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>g</mi><mo>*</mo></msup></math>), establish <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>μ</mi><mi>p</mi></math> colliders as uniquely powerful tools for probing high-mass VLQ states, particularly in the boosted jet regime.

China

Jin-Zhong Han

Yao-Bei Liu

Searching for single production of vectorlike quarks decaying into <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi><mi>b</mi></math> at a future muon-proton collider

We propose a method for probing CP-violation in the heavy (pseudo)scalar sector of an extended Higgs model, in which we make simultaneous use of the $\textit{HVV}$ ( $$V=W^\pm , Z$$ ) and $$Ht\bar{t}$$ interactions of a heavy Higgs state $\textit{H}$. The CP-even component of $\textit{H}$ can be probed through the tree-level $\textit{HVV}$ interaction, while the CP-odd component of $\textit{H}$ can be probed if the final $$t\bar{t}$$ pair can be tested to form a $$^1S_0$$ state. We can then confirm CP-violation if both CP-even and CP-odd components of $\textit{H}$ are discovered. This is possible at the Compact Linear Collider (CLIC) by exploiting $\textit{H}$ production from vector-boson fusion (VBF) and decay to $$t\bar{t}$$ pairs. We analyze the distribution of the azimuthal angle between the leptons coming from top and antitop quarks, which allows one to disentangle the CP nature of such a heavy Higgs state. We also show its implications for the two-Higgs-doublet model (2HDM) with CP-violation.

Taiwan

Kingman Cheung

Ying-nan Mao

Rui Zhang

Testing CP-violation in a heavy Higgs sector at CLIC

We explain the ATOMKI anomaly with a very light $\textit{Z}$′ state that features non-anomalous and non-flavour-universal vector and axial-vector couplings to all leptons. This $\textit{Z}$′ comes from a theoretical framework with a spontaneously broken U(1)′ symmetry in addition to the Standard Model gauge group and is compliant with current measurements of the anomalous magnetic moments of the electron and the muon as well as beam dump experiments. The lepton flavour structure of this model allows for $\textit{Z}$′ couplings to all light neutrinos, suggesting the possibility of $\textit{Z}$′-mediated Non-Standard Interactions (NSIs) of neutrinos in matter, so that measurements of the strength parameters of the NSIs can constrain the value of the couplings. We use experimental constraints on NSIs of neutrinos using older TEXONO data and newer IceCube data. The IceCube data, in particular, strongly constrain the flavour universality of the leptonic vector current. The constraints enable us to define the region of parameter space of this theoretical scenario that can be pursued in further phenomenological analyses.

Rikard Enberg

Türkiye

Yaşar Hiçyılmaz

Carlos Heros

Constraints on the $\textit{X}$17 boson from IceCube searches for non-standard interactions of neutrinos

In this paper, we tension the scope of the $$ q\overline{q} $$ , $\textit{gg}$ → $$ T\overline{T} $$ production process against that of the same-charge $\textit{uu}$ → $\textit{TT}$ one in searching for Vector-Like Quarks (VLQs) with electromagnetic charge +2/3 at the Large Hadron Collider (LHC). The study is conducted by considering a simplified model in which such new states couple exclusively to Standard Model quarks of the first generation through $\textit{W}$ , $\textit{Z}$ and $\textit{H}$ currents. We consider both left-handed or right-handed dominant chiralities, representative of SU(2) singlets or doublets, and the total widths are allowed to reach large values relatively to the VLQ masses. By deconstructing the signal into all its components, we assess current and projected constraints, emphasize the role of interference terms and isolate peculiar features which can be used for dedicated searches at the LHC or future colliders.

Liangliang Shang

Vector-like tops from first generation quarks: the role of width and coupling chiralities in same-charge production at the LHC

The supersymmetric custodial triplet model (SCTM), which is a fully supersymmetric generalization of the Georgi-Machacek (GM) model, is constructed by extending the Higgs sector of the minimal supersymmetric standard model by three triplet chiral superfields with hypercharge <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Y</mi><mo>=</mo><mn>0</mn><mo>,</mo><mo>±</mo><mn>1</mn></math>, in order to maintain the holomorphy of the superpotential and satisfy the requirements of anomaly cancellation. The global <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mi>U</mi><mo stretchy="false">(</mo><mn>2</mn><msub><mo stretchy="false">)</mo><mi>L</mi></msub><mo stretchy="false">⊗</mo><mi>S</mi><mi>U</mi><mo stretchy="false">(</mo><mn>2</mn><msub><mo stretchy="false">)</mo><mi>R</mi></msub></math> symmetry has to be respected for the superpotential and soft supersymmetry breaking sector, where the former will only be broken by the Yukawa couplings and the latter one will be broken spontaneously to the custodial <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mi>U</mi><mo stretchy="false">(</mo><mn>2</mn><msub><mo stretchy="false">)</mo><mi>V</mi></msub></math> symmetry after electroweak symmetry breaking similar to the GM model. The ensuing complicated spectrum not only gives rich collider phenomenology but also provides more available weakly interacting massive particle (WIMP) dark matter (DM) candidates. In this paper, we explore the viability of WIMP solutions for DM in the SCTM, by considering the increasingly stringent constraints from direct detection DM experiments. Our numerical simulations show that a significant portion of the SCTM parameter space remains viable despite these constraints and will be fully tested in future experiments.

Yuanping Wang

Xiaokang Du

Bingfang Yang

Triplet fermion WIMP dark matter in the general supersymmetric Georgi-Machacek model