We study the cosmological gravitational particle production (CGPP) of spin- $$ \frac{3}{2} $$ particles during and after cosmic inflation, and map the parameter space that can realize the observed dark matter density in stable spin- $$ \frac{3}{2} $$ particles. Originally formulated by Rarita and Schwinger, the relativistic theory of a massive spin- $$ \frac{3}{2} $$ field later found a home in supergravity as the superpartner of the graviton, and in nuclear physics as baryonic resonances and nuclear isotopes. We study a minimal model realization, namely a free massive spin- $$ \frac{3}{2} $$ field minimally coupled to gravity, and adopt the name raritron for this field. We demonstrate that CGPP of raritrons crucially depends on the hierarchy between the raritron mass $\textit{m}$ and the Hubble parameter at the end of inflation $\textit{H}$ , with high-mass and low-mass cases distinguished by the evolution of the sound speed $\textit{c}$ of the longitudinal (helicity- $$ \frac{1}{2} $$ ) mode, which is approximately unity at all times for heavy (relative to Hubble) raritrons and can become small or vanish for lighter raritrons, leading to a dramatic enhancement of production of high momentum particles in the latter case. Assuming the raritrons are stable, this leads to a wide parameter space to produce the observed dark matter density. Finally, we consider a time-dependent raritron mass, which can be chosen to remove the vanishing sound speed of the longitudinal mode, but which nonetheless enhances the production relative to the constant high-mass case, and in particular does not necessarily tame the high momentum tail of the spectrum. We perform our calculations using the Bogoliubov formalism and compare, when applicable, to the Boltzmann formalism.

United States

Edward Kolb

Andrew Long

Canada

Evan McDonough

Jingyuan Wang

Creation of spin- $$ \frac{3}{2} $$ dark matter via cosmological gravitational particle production

<p>We investigate the radiative decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>10753</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>γ</mi><msub><mi>X</mi><mrow><mi>b</mi><mn>0</mn></mrow></msub></math> within the framework of nonrelativistic effective field theory (NREFT). The <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>10753</mn><mo stretchy="false">)</mo></math> is treated as an <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>S</mi><mtext>−</mtext><mi>D</mi></mrow></math> mixed state of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>4</mn><mi>S</mi><mo stretchy="false">)</mo></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="normal">ϒ</mi><mn>1</mn></msub><mo stretchy="false">(</mo><mn>3</mn><mrow><msub><mrow><mmultiscripts><mrow><mi>D</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>3</mn></mrow></mmultiscripts></mrow><mrow><mn>1</mn></mrow></msub></mrow><mo stretchy="false">)</mo></math>, while the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>X</mi><mrow><mi>b</mi><mn>0</mn></mrow></msub></math> is interpreted as a weakly bound <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> molecule with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>J</mi><mrow><mi>P</mi><mi>C</mi></mrow></msup><mo>=</mo><msup><mn>0</mn><mrow><mo>+</mo><mo>+</mo></mrow></msup></math>. The decay process was assumed to occur via the intermediate meson loops involving the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math>-wave <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mrow><mo stretchy="false">(</mo><mo>*</mo><mo stretchy="false">)</mo></mrow></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>P</mi></math>-wave <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mn>1</mn><mrow><mo stretchy="false">(</mo><mo>′</mo><mo stretchy="false">)</mo></mrow></msubsup></math> mesons. Our calculated results indicate that the decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>10753</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>γ</mi><msub><mi>X</mi><mrow><mi>b</mi><mn>0</mn></mrow></msub></math> is dominated by the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mn>1</mn><mrow><mo stretchy="false">(</mo><mo>′</mo><mo stretchy="false">)</mo></mrow></msubsup></math> meson loops. The partial decay width is predicted to be 0.2–1.5 keV for a binding energy range of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ε</mi><mi>X</mi></msub><mo>=</mo><mn>0</mn><mi>–</mi><mn>10</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi></math>, corresponding to a branching fraction of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>10</mn><mrow><mo>−</mo><mn>6</mn></mrow></msup><mo>−</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup></math>. The decay width is found to be insensitive to the full width of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mn>1</mn><mo>′</mo></msubsup></math> meson. Our study suggests that the radiative decay of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>10753</mn><mo stretchy="false">)</mo></math> is a promising channel to search for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>X</mi><mrow><mi>b</mi><mn>0</mn></mrow></msub></math> state, which is crucial for testing heavy quark symmetries and understanding the exotic hadron spectrum in the bottom sector.</p>

China

Yuan-Jun Gao

Gang Li

Shi-Dong Liu

Qi Wu

Hunting for <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> molecular state <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>X</mi><mrow><mi>b</mi><mn>0</mn></mrow></msub></math> via radiative transition of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>10753</mn><mo stretchy="false">)</mo></math>

In this note we consider examples of decomposition (in which a local QFT is equivalent to a disjoint union of multiple independent theories, known as universes) where there is a continuous family of universes, rather than a finite or countably infinite collection. In particular, this allows us to consistently eliminate all instantons in a local QFT via a suitable topological gauging of the ($\textit{−}$1)-form symmetry. In two dimensional U(1) gauge theories, this is equivalent to changing the gauge group to $\textit{ℝ}$. This makes both locality as well as the instanton restriction explicit. We apply this to clarify the Gross-Taylor string interpretation of the decomposition of two-dimensional pure Yang-Mills. We also apply decomposition to study two-dimensional $\textit{ℝ}$ gauge theories, such as the pure $\textit{ℝ}$ Maxwell theory, and two-dimensional supersymmetric gauged linear sigma models whose gauge groups have factors of $\textit{ℝ}$. In that context, we find that analogues of the Witten effect for dyons, here rotating between universes, play a role in relating anomalies of the individual universes to (different) anomalies in the disjoint union. Finally, we discuss limits of the Tanizaki-Ünsal construction, which accomplish instanton restriction by topologically gauging a $\textit{ℚ}$/$\textit{ℤ}$ ($\textit{−}$1)-form symmetry, and speculate in two-dimensional theories on possible interpretations of those limits in terms of the adelic solenoid.

Alonso Perez-Lona

Eric Sharpe

Xingyang Yu

Hao Zhang

Total instanton restriction via multiverse interference: Noncompact gauge theories and (−1)-form symmetries

The physical origin of spacetime discreteness remains a central open problem in quantum gravity, with most existing approaches relying on specific microscopic structures or model-dependent assumptions. In this letter, spacetime discreteness can arise instead as a consequence of consistent microscopic measurement. By treating infinitesimal spacetime intervals as scale-dependent measurement outcomes rather than predefined geometric entities, we formulate a Micro-Measurement Principle in which spacetime quantum fluctuations are encoded directly in the scaling structure. An equivalent dual representation of microscopic lengths leads to discrete, equidistant measurement outcomes, with the corresponding scaling-deformed uncertainty relation thereby reducing to the standard Heisenberg form. The microscopic lengths are further governed by a geometric renormalization-group flow admitting finite-length fixed points. This construction preserves Lorentz invariance and general covariance without ad hoc cutoffs or symmetry breaking. Our results show that the classical continuous-spacetime description corresponds to an unstable limiting regime, whereas a finite microscopic length and a discrete spacetime structure arise naturally from the fundamental requirements of micro-measurement consistency.

Weihu Ma

Yu-Gang Ma

Spacetime discreteness via consistent microscopic measurement

In gravitational theories containing matter fields and higher-derivative corrections, the standard Smarr formula often fails unless $\textit{all}$ dimensionful couplings are incorporated consistently. Traditionally, parameters such as the cosmological constant or the coefficients of higher-derivative terms are regarded as immutable features of the theory and therefore excluded from the thermodynamic phase space. In our recent work, we developed a fully general framework that promotes every such coupling to a dynamical, freely varying parameter of black hole solutions. This is accomplished by introducing, for each coupling, an auxiliary scalar and gauge field, through which the coupling appears as a conserved charge associated with the global sector of an emergent gauge symmetry. The corresponding conjugate variables naturally arise as electric potentials evaluated at the black hole horizon. As a result, the first law and the Smarr relation acquire additional, systematically determined contributions, yielding a consistent and universal extension of black hole thermodynamics. We illustrate the validity of this construction by revisiting several black hole examples in the literature where the Smarr formula remains inconsistent even after treating the cosmological constant as a thermodynamic variable. Our analysis shows that only by including $\textit{all}$ dimensionful couplings in this generalized manner can one obtain an internally consistent Smarr relation, thereby providing the foundation for a truly universal formulation of black hole thermodynamics.

Türkiye

Germany

Kamal Hajian

Bayram Tekin

Onur Uçanok

A universal Smarr formula via coupling constants

Recent advances in the off-shell formulation of the Double Copy (DC) procedure have revealed a profound connection between gauge theories and T-duality invariant frameworks. The main example is Double Field Theory (DFT), emerging as the off-shell DC of Yang-Mills theory up to cubic order in perturbations. Extending this procedure to a higher-derivative gauge theory gives rise to a Higher-Derivative Double Theory (HDDT), which incorporates Weyl gravity along with $\textit{b}$-field and dilaton contributions, all in a T-duality invariant manner. In this work, we show that the quadratic contributions of HDDT are directly related (up to field redefinitions) to DFT+, a T-duality invariant model associated with the bosonic string that incorporates first-order $\textit{α}$ corrections upon parameterization. Our results expand the potential applications of the off-shell DC program towards constructing perturbative $\textit{α}$ -corrected Lagrangians, while also opening up possibilities for reversing the map by considering the single and zeroth copies.

Poland

Eric Lescano

Argentina

Jesus Rodriguez

Higher-derivative corrections via the double copy procedure

In the Standard Model, the couplings between gauge bosons are tightly constrained by the principles of gauge symmetry and renormalizability. However, the presence of anomalous couplings suggests the possibility of new physics beyond the Standard Model (BSM). In this study, we focus on the sensitivities of anomalous quartic gauge couplings (aQGCs), specially the dimension-8 operators associated with field-strength tensor structures within the effective field theory (EFT) framework, at future Muon Colliders. Our analysis targets the neutral aQGC-sensitive processes $\textit{μ}$ $\textit{μ}$ → $\textit{μ}$ $\textit{γγμ}$ and $\textit{μ}$ $\textit{μ}$ → $\textit{μ}$ $\textit{Zγμ}$ , simulated at center-of-mass energies of 3 TeV and 10 TeV. Signal and background events are generated using MadGraph5_aMC@NLO, interfaced with Pythia8 for parton showering and hadronization, and Delphes for fast detector simulation. A multivariate analysis based on Boosted Decision Trees (BDTs) is employed to enhance signal-to-background discrimination, utilizing a comprehensive set of kinematic and reconstructed observables from the final-state particles. Unitarity is preserved through the application of an energy-dependent clipping procedure within the EFT validity regime.

M. Tekin

A. Senol

H. Denizli

Constraints on anomalous quartic gauge couplings via $\textit{γγ}$ and $\textit{Zγ}$ vector boson scattering at muon colliders

We formulate a boundary-residual-closure mechanism to systematically construct finite-parameter open XXZ Hamiltonians featuring non-diagonal boundary data. By retaining the standard trigonometric XXZ <italic>R</italic>-matrix, we promote the auxiliary boundary entries to operator-valued generators and establish the sixteen reflection-residual components as the defining relations of a boundary extension algebra. Reducing this algebraic system to its regular Hermitian scalar sector endogenously generates a non-diagonal six-vertex boundary representative, ensuring that the required amplitude and phase emerge prior to the formulation of the double-row transfer object. Subsequently, we embed this residual-generated representative into a mixed detuned double-row seed. By extracting the regularity-point logarithmic derivative of this composite structure, we derive an explicit Hermitian open XXZ Hamiltonian with a transverse left boundary field. Ultimately, this exact mathematical framework ensures the resulting system strictly recovers the standard diagonal open XXZ chain as its zero-amplitude anchor.

Ze Tao

Fujun Liu

Algebraic construction of finite-parameter open XXZ Hamiltonians via boundary residual closure

We investigate how the gravitational effects of a black hole manifest themselves as thermal behavior in the dual finite-temperature conformal field theory (CFT). In the holographic framework of AdS/CFT, we analyze a wave packet propagating into a black hole geometry in the bulk by computing three-point functions of a scalar primary operator in the boundary CFT. Our setup captures thermal signatures such as exponential damping of the expectation value, which are absent at zero-temperature. This provides a concrete and analytically tractable example of how black hole physics can be probed from the CFT side.

Japan

Norihiro Tanahashi

Seiji Terashima

Shiki Yoshikawa

Probing black hole thermal effects in the dual CFT via wave packets

We propose that generalized symmetries in some string-constructed QFTs are given by K-theory. We thus have $\textit{even-form}$ and $\textit{odd-form}$ symmetries determined by $\textit{K}$ ($\textit{∂X}$), the twisted K-theory as D-brane charges on the asymptotic boundary $\textit{∂X}$ of internal geometry $\textit{X}$ with twist class $\textit{N}$. For these QFTs, “$\textit{p-form symmetries}$” are no longer separately well-defined for individual $\textit{p}$, but are instead mixed together. We discuss 6D ADE-type (2,0) SCFTs and some 6d (1,0) LSTs as examples and demonstrate their twisted K-theoretic symmetries, and check that they are compatible with T-duality. We further point out, through explicit examples, that K-theory leads to symmetry extensions that cannot be detected by cohomology for Type II string theory on certain orbifolds of ℂ and ℂ . We also discuss the implications of these results in the dual brane descriptions.

Generalized symmetries in string-constructed QFTs via K-theory