<p>Motivated by the possible 95 GeV diphoton excess, we investigate the capability of the Type-I two-Higgs-doublet model (2HDM-I) to explain this signal under current theoretical and experimental constraints. Using full Monte Carlo simulations for the process of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>p</mi><mo stretchy="false">→</mo><mi>t</mi><mo stretchy="false">(</mo><mo stretchy="false">→</mo><msup><mi>W</mi><mo>+</mo></msup><mi>b</mi><mo stretchy="false">)</mo><mover accent="true"><mi>t</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">(</mo><mo stretchy="false">→</mo><msup><mi>W</mi><mo>−</mo></msup><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">)</mo><mi>h</mi><mo stretchy="false">(</mo><mo stretchy="false">→</mo><mi>γ</mi><mi>γ</mi><mo stretchy="false">)</mo></math>, we evaluate the discovery potential of a 95 GeV Higgs boson at future colliders. Direct Higgs searches strongly constrain the parameter <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>α</mi></math>, excluding the region with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>α</mi><mo>≲</mo><mn>0.95</mn></math>. Monte Carlo results indicate that a minimum cross section of 0.3 fb is required to achieve a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>5</mn><mi>σ</mi></math> signal statistical significance at the high-luminosity LHC (HL-LHC) with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>L</mi><mo>=</mo><mn>3</mn><mtext> </mtext><mtext> </mtext><msup><mi>ab</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>. For the same luminosity, high-energy LHC (HE-LHC) and future circular collider-hadron-hadron (FCC-hh) require 0.67 fb and 2.36 fb, respectively. At the 14 TeV HL-LHC with an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3</mn><mtext> </mtext><mtext> </mtext><msup><mi>ab</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>, parameter regions with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>sin</mi><mo stretchy="false">(</mo><mi>β</mi><mo>−</mo><mi>α</mi><mo stretchy="false">)</mo><mo>≳</mo><mn>0.4</mn></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>sin</mi><mo stretchy="false">(</mo><mi>β</mi><mo>−</mo><mi>α</mi><mo stretchy="false">)</mo><mo>≳</mo><mn>0.25</mn></math> can be probed at the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>5</mn><mi>σ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2</mn><mi>σ</mi></math> significance levels, respectively. At the 27 TeV HE-LHC with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>L</mi><mo>=</mo><mn>10</mn><mtext> </mtext><mtext> </mtext><msup><mi>ab</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>, the sensitivity improves to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>sin</mi><mo stretchy="false">(</mo><mi>β</mi><mo>−</mo><mi>α</mi><mo stretchy="false">)</mo><mo>≳</mo><mn>0.25</mn></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>5</mn><mi>σ</mi></math>) and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>≳</mo><mn>0.15</mn></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2</mn><mi>σ</mi></math>). For the 100 TeV FCC-hh with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>L</mi><mo>=</mo><mn>30</mn><mtext> </mtext><mtext> </mtext><msup><mi>ab</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>, even regions with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>sin</mi><mo stretchy="false">(</mo><mi>β</mi><mo>−</mo><mi>α</mi><mo stretchy="false">)</mo><mo>≳</mo><mn>0.1</mn></math> or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>sin</mi><mo stretchy="false">(</mo><mi>β</mi><mo>−</mo><mi>α</mi><mo stretchy="false">)</mo><mo>≲</mo><mo>−</mo><mn>0.05</mn></math> can be covered at the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>5</mn><mi>σ</mi></math> level. Parameter regions near <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>sin</mi><mo stretchy="false">(</mo><mi>β</mi><mo>−</mo><mi>α</mi><mo stretchy="false">)</mo><mo>≈</mo><mn>0</mn></math> remain challenging to probe in the diphoton channel, even with increased energy or luminosity.</p>

China

Yabo Dong

Kun Wang

Jingya Zhu

Probing a type I 2HDM light Higgs boson in the top-pair-associated diphoton channel

We classify the physical operators of the most general bosonic effective gauge theory up to dimension six using on-shell methods. Based on this classification, we compute the complete one-loop anomalous dimension employing both on-shell unitarity-based and geometric techniques. Our analysis fully accounts for the mixing of operators with different dimensions. The results broadly apply to any Effective Field Theory with arbitrary gauge symmetry and bosonic degrees of freedom. To illustrate their utility, we perform a complete cross-check of results on the renormalization of the Standard Model Effective Field Theory (SMEFT), $\textit{O}$($\textit{n}$) scalar theory, and the SMEFT extended with an axion-like particle. Additionally, we present new results for axion-like particles with CP-violating interactions.

Switzerland

Jason Aebischer

Italy

Luigi Bresciani

Nudžeim Selimović

Anomalous dimension of a general effective gauge theory. Part I. Bosonic sector

We introduce the concept of symmetry packaging for quantum field excitations: in a quantum field theory with a gauge group <italic>G</italic>, every local creation operator carries its full set of internal quantum numbers (IQNs) as a single irreducible <italic>G</italic>-block and forbids any partial factorization. We elevate this observation to a symmetry packaging principle, which asserts that packets of IQNs remain intact throughout all physical processes. We analyze a quantum-field excitation in six successive stages: (1) particle creation/annihilation, (2) hybridization with gauge-blind external degrees of freedom (DOFs), (3) tensor-product assembly, (4) isotypic decomposition, (5) packaged superposition/entanglement, and (6) local Gauge-Invariance constraint. We show that packaging survives every stage and culminates in a gauge-invariant physical Hilbert space. These stages unfold within a three packaging layer hierarchy (raw-Fock &#8594; isotypic &#8594; physical) with distinct packaging characters. Packaging alone reproduces familiar charge-superselection rules and, within any fixed-charge sector, admits a new class of packaged entangled states where internal and external DOFs are inseparably locked. We derive necessary and sufficient conditions for such superpositions and show that packaged irreps behave as noise-protected logical qudits. This framework unifies representation theory, superselection, and entanglement under a single mathematical roof and provides a roadmap for constructing and manipulating packaged states in any gauge theory.

Canada

Rongchao Ma

Symmetry packaging I: Irreducible representation blocks, superselection, and packaged entanglement in quantum field theory

In a previous paper, we proposed an entropy function for AdS BPS black holes in M-theory with general magnetic charges, resolving a long-standing puzzle about baryonic charges in three-dimensional holography and offering a prediction for the large-$\textit{N}$ limit of several partition functions whose saddle points have yet to be found. The entropy function is constructed from the master volume of the internal manifold. In this paper, we prove that the entropy of a general class of black holes based on toric geometry can indeed be reformulated as an $$ \mathcal{I} $$ -extremization problem, and we provide a set of examples. As an aside, we also simplify existing proofs of the equivalence between $\textit{a}$-, $\textit{c}$-, and $\textit{F}$-extremizations and their gravitational duals.

United Kingdom

Seyed Hosseini

Alberto Zaffaroni

$$ \mathcal{I} $$ -extremization for AdS

The Frolov black hole (BH) is a charged extension of the Hayward BH, having regularity at the central point <math altimg='si1.svg'><mi>r</mi><mo linebreak='goodbreak' linebreakstyle='after'>=</mo><mn>0</mn></math> and an asymptotically Schwarzschild form for large values of <italic>r</italic>. Such a BH is parameterized by a length scale parameter, <math altimg='si2.svg'><msub><mrow><mi>&#945;</mi></mrow><mrow><mn>0</mn></mrow></msub></math>. In this paper, we analyze the thermodynamic properties, null and timelike geodesics, and shadows of a Frolov BH immersed in a quintessence field. Our results indicate that the smaller BH is locally thermodynamically stable yet globally unstable at all horizon radii. Neither the quintessence parameter nor the other model parameters like the charge <italic>q</italic> and length scale parameter <math altimg='si2.svg'><msub><mrow><mi>&#945;</mi></mrow><mrow><mn>0</mn></mrow></msub></math> change this global instability. We extend the study of the null and timelike geodesics to the vicinity of the BH by analyzing how the geodesic motion depends on the model parameters. Finally, we analyze the shadow of the BH system and find that the shadow radii are sensitively dependent on model parameters. In contrast, the influence of the quintessence parameter itself on the size of the shadow is found to be rather weak.

India

Mrinnoy M. Gohain

Kalyan Bhuyan

Rajnandini Borgohain

Tonmoyee Gogoi

Kakoli Bhuyan

Prabwal Phukon

Frolov black hole surrounded by quintessence - I: Thermodynamics, geodesics and shadows

We propose a minimal scenario for light thermal dark matter (DM) in sub-GeV to GeV range by incorporating a scalar singlet DM in a type-I seesaw scenario extended by an additional Higgs doublet $\textit{ϕ}$ . The latter permits efficient annihilation of light scalar DM into leptonic final states including right-handed neutrinos (RHN). We keep the charged fermion as well as neutral fermion final states in forbidden regime to avoid bounds from indirect search as well as cosmic microwave background (CMB) data. After studying the purely forbidden DM scenario with neutral and charged fermion final states separately, we discuss the interplay of forbidden and non-forbidden channels in generating light thermal DM relic by considering neutral fermions in non-forbidden mode due to relatively weaker constraints. The model can also explain the anomalous magnetic moment of muon, W-mass anomaly and saturate experimental bounds on charged lepton flavour violation and DM direct detection while offering tantalising detection prospects of RHN, the mass of which is kept approximately in the same range as DM.

Debasish Borah

Pritam Das

South Korea

Satyabrata Mahapatra

Narendra Sahu

Light thermal dark matter via type-I seesaw portal

A correction to this paper has been published: https://doi.org/10.1007/JHEP11(2023)198

Armenia

Hasmik Poghosyan

Rubik Poghossian

Erratum to: A note on rank 5/2 Liouville irregular block, Painlevé I and the $$ {\mathcal{H}}_0 $$ Argyres-Douglas theory

This is the first in a series of two papers, in which we compute the third-order QCD corrections to top-antitop production near threshold in $\textit{e}$ $\textit{e}$ collisions. The present paper provides a detailed outline of the strategy of computation in the framework of non-relativistic effective theory and the threshold expansion, applicable more generally to heavy-quark pair production near threshold. It summarizes matching coefficients and potentials relevant to the next-to-next-to-next-to-leading order and ends with the master formula for the computation of the third-order Green function. The master formula is evaluated in part II of the series.

Germany

M. Beneke

Japan

Y. Kiyo

K. Schuller

Third-order correction to top-quark pair production near threshold. Part I. Effective theory set-up and matching coefficients

In left-right symmetric models, the Majorana coupling matrix, <italic>f</italic>, and hence the right-handed neutrino (RHN) mass matrix, admits eight solutions assuming the form of the Dirac coupling matrix is known. Additionally, the coupling matrix depends on the parity-breaking scale, <math altimg='si1.svg'><msub><mrow><mi>v</mi></mrow><mrow><mi>R</mi></mrow></msub></math>, as a new physics scale. RHNs being Majorana in nature can possess a transition magnetic moment (TMM). Neutrino magnetic moments are inherently related to neutrino masses, as neutrino masses imply neutrino magnetic moments. We study, along with small neutrino TMM, the heavy RHN transition magnetic moment contributions to muon <math altimg='si2.svg'><mi>g</mi><mo linebreak='goodbreak' linebreakstyle='after'>&#8722;</mo><mn>2</mn></math>, <math altimg='si3.svg'><msub><mrow><mo stretchy='false'>(</mo><mi>g</mi><mo linebreak='badbreak' linebreakstyle='after'>&#8722;</mo><mn>2</mn><mo stretchy='false'>)</mo></mrow><mrow><mi>&#956;</mi></mrow></msub></math> anomaly for all eight solutions of <italic>f</italic>. We find, of the eight solutions, only two solutions of <italic>f</italic> matrix contribute to the <math altimg='si3.svg'><msub><mrow><mo stretchy='false'>(</mo><mi>g</mi><mo linebreak='badbreak' linebreakstyle='after'>&#8722;</mo><mn>2</mn><mo stretchy='false'>)</mo></mrow><mrow><mi>&#956;</mi></mrow></msub></math> in the experimental predicted range. The range of <math altimg='si1.svg'><msub><mrow><mi>v</mi></mrow><mrow><mi>R</mi></mrow></msub></math> in these cases is found to be <math altimg='si4.svg'><mn>3.4</mn><mo>&#215;</mo><msup><mrow><mn>10</mn></mrow><mrow><mn>3</mn></mrow></msup><mo linebreak='goodbreak' linebreakstyle='after'>&#8722;</mo><mn>1.5</mn><mo>&#215;</mo><msup><mrow><mn>10</mn></mrow><mrow><mn>4</mn></mrow></msup></math> GeV. For a complimentary check, we also study TMM-induced neutrinoless double beta decay ( <math altimg='si5.svg'><mn>0</mn><mi>&#957;</mi><mi>&#946;</mi><mi>&#946;</mi></math>), for the same set of choice of parameters. While certain parameter choices allow RHNs to explain the <math altimg='si3.svg'><msub><mrow><mo stretchy='false'>(</mo><mi>g</mi><mo linebreak='badbreak' linebreakstyle='after'>&#8722;</mo><mn>2</mn><mo stretchy='false'>)</mo></mrow><mrow><mi>&#956;</mi></mrow></msub></math> anomaly, the same configurations lead to an extremely long half-life for <math altimg='si5.svg'><mn>0</mn><mi>&#957;</mi><mi>&#946;</mi><mi>&#946;</mi></math> decay, well beyond experimental reach. Even under extreme magnetic field enhancements, the half-life decreases only marginally, reinforcing the dominance of weak interaction vertices over TMM contributions in <math altimg='si5.svg'><mn>0</mn><mi>&#957;</mi><mi>&#946;</mi><mi>&#946;</mi></math> decay.

Vivek Banerjee

Sasmita Mishra

Magnetic moment of neutrinos in a left-right symmetric model and Interplay of type-I and type-II seesaw

In this work, we develop machine learning techniques to study nonperturbative scattering amplitudes. We focus on the two-to-two scattering amplitude of identical scalar particles and study a toy model where we set the double discontinuity to zero, thereby simplifying the problem numerically. Neural networks provide an efficient parameterization for scattering amplitudes, offering a flexible toolkit to describe the details of their nonperturbative structure. Combined with the bootstrap approach based on the dispersive representation of the amplitude and machine learning’s gradient descent algorithms, they offer a new method to explore the space of consistent S-matrices. We derive bounds on the values of the first two low-energy Taylor coefficients of the amplitude and characterize the resulting amplitudes that populate the allowed region. Crucially, we parallel our neural network analysis with the standard S-matrix bootstrap, both primal and dual, and observe perfect agreement across all approaches.

France

Mehmet Gümüş

Damien Leflot

Piotr Tourkine

Alexander Zhiboedov

The S-matrix bootstrap with neural optimizers. Part I. Zero double discontinuity