We continue the study of 2D gravity—“matrix model” duality on the example of a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mn>2</mn><mo>,</mo><mn>2</mn><mi>p</mi><mo>+</mo><mn>1</mn><mo stretchy="false">)</mo></math> minimal string. We propose a reformulation of the duality, related to a more conventional one by “<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>x</mi><mtext>−</mtext><mi>y</mi></mrow></math> swap” in the language of topological recursion. This formulation elucidates some conceptual and technical difficulties in the dictionary of the duality and relation to other examples. In particular, it allows to circumvent the necessity to use “resonance transformations,” which were previously introduced to match the world sheet and “matrix model” correlators, and the expressions for minimal string amplitudes in this approach are reminiscent of the ones obtained recently for “complex Liouville string” theory. Using this new approach, we also formulate a conjecture on how one can compute amplitudes with operators other than tachyons in the dual theory.

Russia

Aleksandr Artemev

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>x</mi><mtext>−</mtext><mi>y</mi></mrow></math> swap for a (2, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>2</mn><mi>p</mi><mo>+</mo><mn>1</mn></mrow></math>) minimal string

We consider correlation functions of two maximal giant gravitons and two light <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mfrac><mn>1</mn><mn>2</mn></mfrac></math>-BPS (Bogomol’nyi–Prasad–Sommerfield) operators in 4D <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">N</mi><mo>=</mo><mn>4</mn></math> SYM (super Yang-Mills). Viewed as two-point correlators in the presence of a zero-dimensional defect, they can be completely fixed at strong coupling using analytic bootstrap techniques. We determine all infinitely such correlators for arbitrary light <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac></mrow></math>-BPS operators and find that the result can be repackaged into a simple generating function thanks to a hidden higher-dimensional symmetry. We also find evidence that the same symmetry holds at weak coupling for loop correction integrands.

China

Junding Chen

Yunfeng Jiang

Xinan Zhou

Giant Graviton Correlators as Defect Systems

With the help of a semiclassical kinetic theory, a new collision kernel is proposed, which simultaneously conserves the energy-momentum tensor and the spin tensor of a relativistic fluid of spin-1/2 particles irrespective of the frame and matching conditions, even when relaxation time is momentum dependent. The relativistic Boltzmann's equation is solved using this new collision kernel that will lead to the transport coefficients with general definitions for the frame and matching conditions. The results indicate the expected existence of Barnett-like effect and the nonexistence of Einstein–de Haas–like effects. For the first time, a local collision kernel is being proposed that can be used to construct relativistic spin hydrodynamics along the line of Bemfica-Disconzi-Noronha-Kovtun (BDNK) formulation, which may lead to a first-order stable and causal theory.

Poland

Samapan Bhadury

Relativistic spin hydrodynamics from novel relaxation time approximation

Using the Zubarev’s nonequilibrium statistical operator formalism, we derive the second-order expression for the dissipative tensors in relativistic spin hydrodynamics, viz. rotational stress tensor (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>τ</mi><mrow><mi>μ</mi><mi>ν</mi></mrow></msub></math>), boost heat vector (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>q</mi><mi>μ</mi></msub></math>), shear stress tensor (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>π</mi><mrow><mi>μ</mi><mi>ν</mi></mrow></msub></math>), and bulk viscous pressure (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Π</mi></math>). The first two (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>τ</mi><mrow><mi>μ</mi><mi>ν</mi></mrow></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>q</mi><mi>μ</mi></msub></math>) emerge due to the inclusion of the antisymmetric part in the energy-momentum tensor, which, in turn, governs the conservation of spin angular momentum (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi mathvariant="normal">Σ</mi><mrow><mi>α</mi><mi>μ</mi><mi>ν</mi></mrow></msup></math>). As a result, new thermodynamic forces, generated due to the antisymmetric part of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>μ</mi><mi>ν</mi></mrow></msub></math>, contain the spin chemical potential. In this work, we have also taken the spin density (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>S</mi><mrow><mi>μ</mi><mi>ν</mi></mrow></msup></math>) as an independent thermodynamic variable, in addition to the energy density and particle density, thereby resulting in two novel transport coefficients given by the correlation between spin density tensor and rotational stress tensor and vice versa. Additionally, the newly found terms in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>π</mi><mrow><mi>μ</mi><mi>ν</mi></mrow></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Π</mi></math> are the artifacts of the new thermodynamic forces that arise due to the antisymmetric part of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>T</mi><mrow><mi>μ</mi><mi>ν</mi></mrow></msup></math>. Finally, we have derived the evolution equations for the aforesaid tensors: <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>τ</mi><mrow><mi>μ</mi><mi>ν</mi></mrow></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>q</mi><mi>μ</mi></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>π</mi><mrow><mi>μ</mi><mi>ν</mi></mrow></msub></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Π</mi></math>.

India

Abhishek Tiwari

Binoy Krishna Patra

Second-order spin hydrodynamics from Zubarev’s nonequilibrium statistical operator formalism

This paper presents a novel tagging technique to measure the beauty-quark partial decay-width ratio $$R_b$$ and its forward–backward asymmetry $$A_{\textrm{FB}}^b$$ at the FCC-ee, using $$\mathcal {O}(10^{12})$$ $\textit{Z}$-boson decays. The method is based on the exclusive reconstruction of a selected list of $\textit{b}$-hadron decay modes in $$Z\rightarrow b\bar{b}$$ events at the $\textit{Z}$ pole, which can provide the flavour and possibly the charge of the hemisphere. This approach effectively eliminates the contamination from light-quark physics events and reduces the leading systematic uncertainties arising from background contamination, tagging-efficiency correlations, and gluon-radiation corrections by exploiting the geometric and kinematic properties of beauty hadrons. This results in a total relative uncertainty of the order of 0.01 % for both observables. Furthermore, this precision allows to obtain a commensurate precision on the weak mixing angle $$\sin ^2(\theta _\text {W}^{\text {eff}})$$ compared to the muon forward–backward asymmetry on the order of 0.002 %.

Germany

France

Lars Röhrig

Kevin Kröninger

Romain Madar

Stéphane Monteil

Italy

Fabrizio Palla

Switzerland

Emmanuel Perez

Measuring $$A_\textrm{FB}^b$$ and $$R_b$$ with exclusive $\textit{b}$-hadron decays at the FCC-ee

We study nonperturbative effects of torus partition function of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi><mover accent="true"><mi>T</mi><mo stretchy="false">¯</mo></mover></math>-deformed 2D conformal field theory (CFT) by resurgence in this Letter and a companion paper. The deformed partition function can be written as an infinite series of the deformation parameter <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>λ</mi></math>. We develop highly efficient methods to compute perturbative coefficients in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>λ</mi></math> expansion. To exemplify, the first 600 coefficients for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi><mover accent="true"><mi>T</mi><mo stretchy="false">¯</mo></mover></math>-deformed free boson and free fermion are computed. The method can be generalized to any rational CFTs; we present the key idea in this Letter while relegating details and results to the companion paper. Equipped with the large order perturbative data, we provide convincing numerical evidence that the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>λ</mi></math> series is asymptotic and not Borel resummable. We extract the nonperturbative contribution by resurgence and propose that they originate from new complex saddle points after analytically continuing the modular parameters in the integral representation of the partition function. The proposal is checked by comparing the predicted asymptotic behavior of the coefficients and large order perturbative data, which match nicely. The implications of these nonperturbative contributions for the Stokes phenomenon, which relates the positive and negative signs of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>λ</mi></math>, as well as possible comparisons with holography, is also discussed.

Jie Gu

Huajia Wang

Resurgence of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>T</mi><mover accent="true"><mrow><mi>T</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover></mrow></math>-Deformed Partition Function

We compute the four-photon (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>F</mi><mn>4</mn></msup></math>) operators generated by loops of charged particles of spin 0, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mfrac><mn>1</mn><mn>2</mn></mfrac></math>, 1 in the presence of gravity and in any spacetime dimension <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>d</mi></math>. To this end, we expand the one-loop effective action via the heat kernel coefficients, which capture both the gravity-induced renormalization of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>F</mi><mn>4</mn></msup></math> operators and the low-energy Einstein-Maxwell effective field theory (EFT) produced by massive charged particles. We set positivity bounds on the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>F</mi><mn>4</mn></msup></math> operators using standard arguments from extremal black holes (for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>d</mi><mo>≥</mo><mn>4</mn></math>) and from infrared (IR) consistency of four-photon scattering (for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>d</mi><mo>≥</mo><mn>3</mn></math>). We find that both approaches yield nearly equivalent results, even though in the amplitudes we discard the graviton <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>t</mi></math>-channel pole and use the vanishing of the Gauss-Bonnet term at quadratic order for any <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>d</mi></math>. The positivity bounds constrain the charge-to-mass ratio of the heavy particles. If the Planckian <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>F</mi><mn>4</mn></msup></math> operators are sufficiently small or negative, such bounds produce a version of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>d</mi></math>-dimensional weak gravity conjecture (WGC) in most, but not all, dimensions. In the special case of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>d</mi><mo>=</mo><mn>6</mn></math>, the gravity-induced beta functions of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>F</mi><mn>4</mn></msup></math> operators from charged particles of any spin are positive, leading to WGC-like bounds with a logarithmic enhancement. In <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>d</mi><mo>=</mo><mn>9</mn></math>, 10, the WGC fails to guarantee extremal black hole decay in the infrared EFT, thereby requiring the existence of sufficiently large Planckian <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>F</mi><mn>4</mn></msup></math> operators.

Brazil

Pedro Bittar

Sylvain Fichet

Lucas de Souza

Gravity-induced photon interactions and infrared consistency in any dimensions

We elaborate on the resurgence analysis on the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi><mover accent="true"><mi>T</mi><mo stretchy="false">¯</mo></mover></math>-deformed 2D conformal field theory (CFT). Writing the deformed partition function as an infinite series in the deformation parameter <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>λ</mi></math>, we develop efficient analytical methods to compute high-order terms of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>λ</mi></math>-series. Based on the asymptotic behavior of the large-order perturbative series, we show that the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>λ</mi></math>-series is asymptotic and extract nonperturbative contributions by resurgence. This paper extends a previous Letter of the same authors to interacting rational CFTs, with Lee-Yang CFT as a concrete example. We also discuss possible implications of the resurgence results on holography.

Resurgent properties of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi><mover accent="true"><mi>T</mi><mo stretchy="false">¯</mo></mover></math>-deformed conformal field theories

We investigate the possible existence of double-strangeness hidden-charm pentaquark states, denoted as <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>P</mi></mrow><mrow><mi>c</mi><mover accent="true"><mrow><mi>c</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mi>s</mi><mi>s</mi></mrow></msub></mrow></math>, within an off-shell coupled-channel formalism. Eleven meson–baryon channels with total strangeness <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mo>=</mo><mo>−</mo><mn>2</mn></math> are constructed by combining charmed mesons and singly charmed baryons. The two-body scattering amplitudes are derived from an effective Lagrangian that respects heavy-quark spin symmetry, hidden local symmetry, and flavor SU(3) symmetry. The Bethe-Salpeter equation is solved using the Blankenbecler-Sugar reduction scheme, and resonances are identified as poles in the scattering amplitudes on the complex energy plane. We find five negative-parity <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>P</mi><mrow><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mi>s</mi><mi>s</mi></mrow></msub></math> states with spins <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>=</mo><mn>1</mn><mo>/</mo><mn>2</mn></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3</mn><mo>/</mo><mn>2</mn></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>5</mn><mo>/</mo><mn>2</mn></math>, all located below their relevant thresholds. Three positive-parity states are also found: two with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>=</mo><mn>1</mn><mo>/</mo><mn>2</mn></math> and one with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>=</mo><mn>3</mn><mo>/</mo><mn>2</mn></math>, lying above the thresholds with substantial widths. The coupling strengths of each resonance to relevant meson-baryon channels are extracted. The sensitivity of the results to the cutoff parameter <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="normal">Λ</mi><mn>0</mn></msub><mo>=</mo><mi mathvariant="normal">Λ</mi><mo>−</mo><mi>m</mi></math> is examined. These results provide theoretical predictions that may assist future experimental searches for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>P</mi><mrow><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mi>s</mi><mi>s</mi></mrow></msub></math> states in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mi mathvariant="normal">Ξ</mi></math> channel.

South Korea

Samson Clymton

Hyun-Chul Kim

Indonesia

Terry Mart

Double-strangeness hidden-charm pentaquarks

In this study, we present a comprehensive analysis of decay constants and chiral-even and chiral-odd distribution amplitudes (DAs) up to twist 4 for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ρ</mi></math> meson in the standard light-front quark model (LFQM) based on the Bakamjian-Thomas (BT) construction. For the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ρ</mi></math> meson, which possesses both longitudinal (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>h</mi><mo>=</mo><mn>0</mn></mrow></math>) and transverse <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mi>h</mi><mo>=</mo><mo>±</mo><mn>1</mn><mo stretchy="false">)</mo></math> polarizations, two types of decay constants, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>f</mi><mi>ρ</mi><mo stretchy="false">∥</mo></msubsup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>f</mi><mi>ρ</mi><mo>⊥</mo></msubsup></math>, arises accordingly. We demonstrate that these decay constants can be self-consistently extracted from both local (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>z</mi><mi>μ</mi></msup><mo>=</mo><mn>0</mn></math>) and nonlocal (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>z</mi><mi>μ</mi></msup><mo>≠</mo><mn>0</mn></math>) matrix elements <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">⟨</mo><mn>0</mn><mo stretchy="false">|</mo><mover accent="true"><mi>q</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">(</mo><mi>z</mi><mo stretchy="false">)</mo><mi mathvariant="normal">Γ</mi><mi>q</mi><mo stretchy="false">(</mo><mo>−</mo><mi>z</mi><mo stretchy="false">)</mo><mo stretchy="false">|</mo><mi>ρ</mi><mo stretchy="false">(</mo><mi>P</mi><mo>,</mo><mi>h</mi><mo stretchy="false">)</mo><mo stretchy="false">⟩</mo></math>, with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="normal">Γ</mi><mo>=</mo><mo stretchy="false">(</mo><msup><mrow><mi>γ</mi></mrow><mrow><mi>μ</mi></mrow></msup><mo>,</mo><msup><mrow><mi>σ</mi></mrow><mrow><mi>μ</mi><mi>ν</mi></mrow></msup><mo>,</mo><msup><mrow><mi>γ</mi></mrow><mrow><mi>μ</mi></mrow></msup><msub><mrow><mi>γ</mi></mrow><mn>5</mn></msub><mo>,</mo><mn mathvariant="bold">1</mn><mo stretchy="false">)</mo></mrow></math>, in a manner independent of current components, polarizations, and reference frames. In particular, we emphasize the role of nonlocal matrix elements involving axial-vector and scalar currents, where mixing between <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>f</mi><mi>ρ</mi><mo stretchy="false">∥</mo></msubsup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>f</mi><mi>ρ</mi><mo>⊥</mo></msubsup></math> occurs. We show that this mixing is consistently resolved through the BT construction, ensuring the proper extraction of these decay constants. Additionally, we investigate the structure of chiral-even DAs (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>ϕ</mi><mrow><mn>2</mn><mo>;</mo><mi mathvariant="normal">V</mi></mrow><mo stretchy="false">∥</mo></msubsup><mo>,</mo><msubsup><mi>ϕ</mi><mrow><mn>3</mn><mo>;</mo><mi mathvariant="normal">V</mi></mrow><mo stretchy="false">∥</mo></msubsup><mo>,</mo><msubsup><mi>ψ</mi><mrow><mn>3</mn><mo>;</mo><mi mathvariant="normal">A</mi></mrow><mo>⊥</mo></msubsup><mo>,</mo><msubsup><mi>ϕ</mi><mrow><mn>4</mn><mo>;</mo><mi mathvariant="normal">V</mi></mrow><mo stretchy="false">∥</mo></msubsup></math>) and chiral-odd DAs (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>ϕ</mi><mrow><mn>2</mn><mo>;</mo><mi mathvariant="normal">T</mi></mrow><mo>⊥</mo></msubsup><mo>,</mo><msubsup><mi>ϕ</mi><mrow><mn>3</mn><mo>;</mo><mi mathvariant="normal">T</mi></mrow><mo>⊥</mo></msubsup><mo>,</mo><msubsup><mi>ψ</mi><mrow><mn>3</mn><mo>;</mo><mi mathvariant="normal">S</mi></mrow><mo stretchy="false">∥</mo></msubsup><mo>,</mo><msubsup><mi>ϕ</mi><mrow><mn>4</mn><mo>;</mo><mi mathvariant="normal">T</mi></mrow><mo>⊥</mo></msubsup></math>) beyond leading twists, and present their corresponding <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ξ</mi></math>-moments and Gegenbauer moments. These results provide deeper insight into the nonperturbative structure of vector mesons and demonstrate the robustness and self-consistency of the LFQM based on the BT framework.

Japan

Ahmad Jafar Arifi

Ho-Meoyng Choi

United States

Chueng-Ryong Ji

Beyond leading twist: <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ρ</mi></math> meson decay constants and distribution amplitudes in a self-consistent light-front quark model