The dimensional reduction of M-theory couplings at order <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mo>ℓ</mo><mi>p</mi><mn>6</mn></msubsup></math> is known to produce one-loop <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mrow><mi>α</mi></mrow><mrow><mo>′</mo><mn>3</mn></mrow></msup></math> corrections in type IIA string theory. In this paper, we perform the Kaluza-Klein reduction of the M-theory Chern-Simons coupling <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>t</mi><mn>8</mn></msub><msub><mi>ε</mi><mn>11</mn></msub><mi>A</mi><msup><mi>R</mi><mn>4</mn></msup></math> at this order. By meticulously accounting for nongauge-invariant total derivative terms, we derive the complete set of corresponding one-loop, gauge-invariant couplings in the type IIA effective action. Our results not only reproduce the standard Chern-Simons term <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>t</mi><mn>8</mn></msub><msub><mi>ε</mi><mn>10</mn></msub><mi>B</mi><msup><mi>R</mi><mn>4</mn></msup></math>—which is gauge invariant up to total derivatives—but also unveil a new set of gauge-invariant couplings involving Ramond-Ramond and Neveu-Schwarz–Neveu-Schwarz field strengths. To validate our findings, we test their consistency under string dualities. We dimensionally reduce the derived type IIA couplings on a K3 manifold and show that the resulting one-loop <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>α</mi><mo>′</mo></msup></math> corrections in six dimensions transform under S-duality into the dimensional reduction of the tree-level heterotic string Chern-Simons coupling <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>H</mi><mrow><mi>μ</mi><mi>ν</mi><mi>α</mi></mrow></msub><msup><mi mathvariant="normal">Ω</mi><mrow><mi>μ</mi><mi>ν</mi><mi>α</mi></mrow></msup></math> on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>T</mi><mn>4</mn></msup></math>. This nontrivial agreement provides strong evidence for the correctness of both the M-theory Chern-Simons term and its reduction to type IIA.

Iran

Mohammad R. Garousi

Dimensional reduction of the M-theory Chern-Simons term at order <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mo>ℓ</mo><mi>p</mi><mn>6</mn></msubsup></math>

We discuss that the string/M-theory partition function requires a choice of ensembles, depending on which background fields are held fixed. The background fields correspond to worldvolume couplings in the effective action approach to the superstring, which we extrapolate to the M2-brane. One natural ensemble in this context, which we call the M2-ensemble, corresponds to fixing the value of the M-theory three-form potential. In holographic setups the choice of ensemble is important when comparing to observables in the dual field theory. Indeed, in AdS holography the M2-ensemble does not map gravitational observables directly to field theory observables at a fixed rank $\textit{N}$, but rather to observables in the grand canonical ensemble. We remark that many M2-brane partition functions take a simple form in this ensemble hinting at one-loop exactness. We also discuss how in AdS holography, the M2-ensemble does correspond to the canonical ensemble in the field theory, i.e. the (2,0) theory at fixed rank $\textit{N}$.

United Kingdom

Friðrik Gautason

Jesse Muiden

Ensembles in M-theory and holography

Within the framework of the next-to-minimal supersymmetric (SUSY) extension of the Standard Model (SM) with a local B-L gauge symmetry (N-B-LSSM), we study lepton flavor violating (LFV) $ \tau\rightarrow e M^+ M^- $ decays: $ \tau \rightarrow e \pi^+\pi^- $ , $ \tau \rightarrow e \pi^+K^- $ , and $ \tau \rightarrow e K^+K^- $ . Based on the latest experimental data, the influence of different sensitive parameters on the branching ratios is considered. It can be seen from the numerical analysis that the main sensitive parameters and LFV sources are non-diagonal elements corresponding to the initial and final leptons. This work can provide a basis for discovering the existence of new physics (NP).

China

Rong-Zhi Sun

Shu-Min Zhao

Shuang Di

Portugal

Xing-Xing Dong

Study of ${\boldsymbol\tau\rightarrow {\boldsymbol e M^+ M^-}}$ decays in N-B-LSSM * Supported by National Natural Science Foundation of China (NNSFC) (12075074), Natural Science Foundation of Hebei Province (A2023201040, A2022201022, A2022201017, A2023201041), Natural Science Foundation of Hebei Education Department (QN2022173), Post-graduate's Innovation Fund Project of Hebei University (HBU2024SS042), the Project of the China Scholarship Council (CSC) (202408130113). X. Dong acknowledges support from Fundação para a Ciência e a Tecnologia (FCT, Portugal) through the projects CFTP FCT Unit (UIDB/00777/2020, UIDP/00777/2020)

We present the first calculation of the high-energy corrections to the process of isolated photon production in association with two jets. These corrections both stabilise the perturbative behaviour in $$ {m}_{j_1{j}_2} $$ and lead to a significantly improved description of data from a recent ATLAS measurement.

Switzerland

Jeppe Andersen

Spain

Andreas Maier

Malina Rosca

Germany

Giacomo Ruisi

Stable perturbative predictions for isolated photon production with a jet pair at large $$ {m}_{j_1{j}_2} $$

We present the perturbative results of the discretization errors proportional to the quark mass [<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">O</mi><mo stretchy="false">(</mo><mi>a</mi><mi>m</mi><mo stretchy="false">)</mo></math>] on the QCD running coupling within lattice perturbation theory. Our analysis involves calculating the two-loop renormalization factor <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>g</mi></msub></math> using improved lattice actions for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mi>U</mi><mo stretchy="false">(</mo><msub><mi>N</mi><mi>c</mi></msub><mo stretchy="false">)</mo></math> gauge group and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>N</mi><mi>f</mi></msub></math> multiplets of fermions with a finite quark mass. We employ the background field method to compute <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>g</mi></msub></math>, by calculating quantum corrections on both the background and quantum gluon propagator, respecting the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">O</mi><mo stretchy="false">(</mo><mi>a</mi><mo stretchy="false">)</mo></math> improvement. This allows us to evaluate the perturbative <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">O</mi><mo stretchy="false">(</mo><mi>a</mi><mi>m</mi><mo stretchy="false">)</mo></math> lattice errors which affect the determination of the running coupling. Eliminating these <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">O</mi><mo stretchy="false">(</mo><mi>a</mi><mi>m</mi><mo stretchy="false">)</mo></math> effects is crucial for the nonperturbative studies of precision determinations of the strong coupling constant using lattice field theory.

Cyprus

M. Costa

D. Gavriel

H. Panagopoulos

G. Spanoudes

Perturbative determination of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">O</mi><mo stretchy="false">(</mo><mi>a</mi><mi>m</mi><mo stretchy="false">)</mo></math> improvement on the QCD running coupling

To give more credence to the M-theoretic Emergence Proposal it is important to show that also classical kinetic terms in a low energy effective action arise as a quantum effect from integrating out light towers of states. We show that for compactifications of type IIA on Calabi-Yau manifolds, the classical weak coupling Yukawa couplings, which are the triple intersection numbers of the Calabi-Yau threefold, can be obtained from the 1/2-BPS protected one-loop Schwinger integral over $\textit{D}$2-$\textit{D}$0 bound states, after employing a novel regularization for the final infinite sum of Gopakumar-Vafa invariants. Approaching the problem in a consecutive manner from 6D decompactification over emergent string to the ultimate M-theory limits, we arrive at a mathematically concrete regularization that involves finite distance degeneration limits of Calabi-Yau threefolds in an intriguing way. We test and challenge this proposal by the concrete determination of the periods around such degeneration points for threefolds with one Kähler modulus and the two examples $\textit{ℙ}$ [18] and $\textit{ℙ}$ [12].

Ralph Blumenhagen

Aleksandar Gligovic

Emergence of CY triple intersection numbers in M-theory

Axionlike particles (ALPs), hypothetical particles beyond the Standard Model (SM), are considered as promising dark matter candidates. ALPs can convert into photons and vice versa in a magnetic field via the Primakoff effect, potentially generating detectable oscillation in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi></math>-ray spectra. This study analyzes 16.5 years of data from the Fermi Large Area Telescope (Fermi-LAT) on NGC 1275, the brightest galaxy in the Perseus cluster, to constrain the ALP parameter space. Our results improve the previous 95% exclusion limits of the photon-ALP coupling <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>g</mi><mrow><mi>a</mi><mi>γ</mi></mrow></msub></math> by a factor of 2 in the ALP mass range of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>4</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>10</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi><mo>≲</mo><msub><mi>m</mi><mi>a</mi></msub><mo>≲</mo><mn>5</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>9</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi></math>. Moreover, we investigate the projected sensitivity of the future Very Large Area <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi></math>-ray Space Telescope (VLAST) on searching for ALPs. We find that (i) the expected sensitivity on the photon-ALP coupling <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>g</mi><mrow><mi>a</mi><mi>γ</mi></mrow></msub></math> can be stronger than that from the upcoming International Axion Observatory in the ALP mass range of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>11</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi><mo>≲</mo><msub><mi>m</mi><mi>a</mi></msub><mo>≲</mo><mn>1</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi></math>, with the best sensitivity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>g</mi><mrow><mi>a</mi><mi>γ</mi></mrow></msub><mo>∼</mo><mn>7</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>13</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>GeV</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>a</mi></msub><mo>∼</mo><mn>2</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>10</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi></math>; (ii) VLAST can extend the sensitivity of the ALP masses below <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>5</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>12</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi></math>, where the photon-ALP coupling <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>g</mi><mrow><mi>a</mi><mi>γ</mi></mrow></msub><mo>≳</mo><mn>1.5</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>11</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>GeV</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> will be excluded; (iii) the entire parameter space of ALP accounting for TeV transparency can be fully tested. These results demonstrate that VLAST will offer an excellent opportunity for ALPs searches.

Zhi-Qi Guo

Yue-Lin Sming Tsai

Lei Wu

Zi-Qing Xia

Constraints on axionlike particles from 16.5 years of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>F</mi><mi>e</mi><mi>r</mi><mi>m</mi><mi>i</mi></math>-LAT data and prospects for VLAST

In this study, we construct a traversable wormhole solution within the framework of <math altimg='si16.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi>L</mi><mi>m</mi></msub><mo>,</mo><mi>T</mi><mo>)</mo></mrow></math> gravity by assuming conformal symmetry. The matter content is modeled using phantom energy, characterized by an equation of state parameter <math altimg='si17.svg'><mrow><mi>&#969;</mi><mo linebreak='goodbreak'>&lt;</mo><mo>&#8722;</mo><mn>1</mn></mrow></math>, which inherently violates the null energy condition. By employing conformal Killing vector symmetry, we derive exact analytical expressions for the shape function, energy density, and pressure components of the anisotropic fluid. Our analysis includes a detailed examination of the flare-out condition, proper radial distance, embedding diagrams, and the generalized Tolman-Oppenheimer-Volkoff equation. Notably, the model yields a positive active gravitational mass and positive total gravitational energy, despite the presence of exotic matter.

Türkiye

Doğukan Taşer

Existence of conformal symmetric wormhole with phantom energy in <math altimg='si16.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi>L</mi><mi>m</mi></msub><mo>,</mo><mi>T</mi><mo>)</mo></mrow></math> theory

In this study, we investigate the viability of the <math altimg='si4.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi mathvariant='script'>L</mi><mi>m</mi></msub><mo>)</mo></mrow></math> gravity framework in explaining the accelerated expansion of the universe within the context of the locally rotationally symmetric (LRS) Bianchi-I space-time. Modified gravity theories have emerged as promising alternatives to General Relativity (GR) to account for cosmic acceleration and dark energy phenomena. We employ observational constraints from Type Ia Supernovae (SN Ia), Baryon Acoustic Oscillations (BAO), and Cosmic Chronometers (CC) to calibrate the free parameters of our model. The field equations are formulated based on a specific functional form of <math altimg='si4.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi mathvariant='script'>L</mi><mi>m</mi></msub><mo>)</mo></mrow></math>, and analytical solutions are obtained. The Hubble parameter, deceleration parameter ( <math altimg='si10.svg'><mi>q</mi></math>), statefinder diagnostics <math altimg='si74.svg'><mrow><mo>(</mo><mi>r</mi><mo>,</mo><mi>s</mi><mo>)</mo></mrow></math>, and the jerk parameter ( <math altimg='si12.svg'><mi>j</mi></math>) are utilized to analyze the evolutionary dynamics of the universe. Our results indicate a transition from a decelerating to an accelerating phase, with the transition redshift <math altimg='si75.svg'><mrow><msub><mi>z</mi><mi>t</mi></msub><mo linebreak='goodbreak'>=</mo><mn>0</mn><mo>.</mo><msubsup><mn>7293</mn><mrow><mo>&#8722;</mo><mn>0.06</mn></mrow><mrow><mo>+</mo><mn>0.07</mn></mrow></msubsup></mrow></math> and present deceleration parameter <math altimg='si76.svg'><mrow><msub><mi>q</mi><mn>0</mn></msub><mo linebreak='goodbreak'>=</mo><mo>&#8722;</mo><mn>0.56</mn></mrow></math>, consistent with observational data. The estimated age of the universe in this framework is <math altimg='si77.svg'><mrow><mn>13.27</mn><mo>&#177;</mo><mn>0.26</mn></mrow></math> Gyrs. The statefinder parameters suggest that the model closely mimics the standard <math altimg='si5.svg'><mstyle mathvariant='normal'><mi>&#923;</mi></mstyle></math>CDM scenario at present but exhibits deviations at earlier epochs, potentially indicating a dynamic nature of dark energy. The <math altimg='si78.svg'><msub><mi>O</mi><mi>m</mi></msub></math> diagnostic further confirms the compatibility of our model with a phantom-like behavior of dark energy. These findings support the viability of <math altimg='si4.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi mathvariant='script'>L</mi><mi>m</mi></msub><mo>)</mo></mrow></math> gravity as an alternative framework for explaining cosmic acceleration, providing new interplay between matter and curvature in gravitational dynamics.

India

Vinod Kumar Bhardwaj

Anil Kumar Yadav

S.H. Shekh

Constraining <math altimg='si4.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi mathvariant='script'>L</mi><mi>m</mi></msub><mo>)</mo></mrow></math> gravity with SN Ia and BAO observational data in Bianchi I space time

We construct superinvariants in M-theory via local supersymmetry, which include ($\textit{DF}$) terms and fermionic bilinear terms with mass dimension eight. The bases of the ($\textit{DF}$) and the fermionic bilinear terms are classified and the variations under the local supersymmetry are evaluated by using the Mathematica codes. By imposing the local supersymmetry, we find that 24 independent terms of ($\textit{DF}$) are governed by 10 parameters. The result is consistent with the effective action obtained by analyzing scattering amplitudes of superparticles or supermembranes.

Japan

Yoshifumi Hyakutake

Effective action in M-theory: ($\textit{DF}$)