Precision measurements of top-quark production with energetic photons provide a complementary probe of vectorlike quarks with nonstandard radiative decays. We reinterpret the CMS differential <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><mi>γ</mi></math> measurement and the ATLAS fiducial <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><mi>γ</mi><mi>γ</mi></math> cross section to constrain the electromagnetic and chromomagnetic transition interactions of a charge-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2</mn><mo>/</mo><mn>3</mn></math> vectorlike top partner, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi></math>. We consider effective interactions written in terms of physical fields after electroweak symmetry breaking, retaining only the decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi><mo stretchy="false">→</mo><mi>t</mi><mi>γ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi><mo stretchy="false">→</mo><mi>t</mi><mi>g</mi></math>. The CMS signal includes both the mixed <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mi>t</mi><mi>γ</mi><mo stretchy="false">)</mo><mo stretchy="false">(</mo><mi>t</mi><mi>g</mi><mo stretchy="false">)</mo></math> topology and double-radiative <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><mi>γ</mi><mi>γ</mi></math> events entering the exactly-one-photon fiducial region, while the ATLAS rate is interpreted using a signal-specific detector-response transfer factor. Signal uncertainties are included, and the interpretation is restricted point by point to the domain satisfying the effective field theory and narrow-width requirements. Denoting the electromagnetic and chromomagnetic transition coefficients by <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>c</mi><mrow><mi>t</mi><mi>γ</mi></mrow></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>c</mi><mrow><mi>t</mi><mi>g</mi></mrow></msub></math>, respectively, we find that, for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>c</mi><mrow><mi>t</mi><mi>g</mi></mrow></msub><mo>=</mo><mn>1.0</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>GeV</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>T</mi></msub><mo>=</mo><mn>500</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>, the observed Run 2 exclusions at 95% confidence level extend down to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>c</mi><mrow><mi>t</mi><mi>γ</mi></mrow></msub><mo>≃</mo><mn>4.7</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>GeV</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> for CMS and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2.3</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>6</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>GeV</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> for ATLAS within the valid domain. At <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>T</mi></msub><mo>=</mo><mn>1000</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>, the corresponding values are <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2.1</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>6</mn></mrow></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>8.5</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>6</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>GeV</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>. Projections to the HL-LHC indicate improved sensitivity to these radiative transition interactions. These results establish top-associated photon measurements as complementary probes of radiative top-partner interactions beyond searches targeting conventional decay modes.

Iran

M. Sahraei

Y. Hosseini

M. Mohammadi Najafabadi

Constraints on vectorlike top dipole interactions from top-associated photon measurements at the LHC

Scintillating molecular crystals have emerged as prime candidates for directional dark matter detector targets. This anisotropy makes them exquisitely sensitive due to the daily modulation induced by the directional dark matter wind. However, predicting the interaction rate for arbitrary molecules requires accurate modeling of the many-body ground as well as excited states, a task that has been historically computationally expensive. Here, we present a theory and computational framework for efficiently computing dark matter scattering form factors for molecules. We introduce scarfff, a GPU-accelerated code to compute the fully three-dimensional anisotropic molecular form factor for arbitrary molecules. We use a full time-dependent density functional theory framework to compute the lowest-lying singlet excited states. Once the many-body electronic structure is computed, the form factors are computed in a small fraction of the time from the transition density matrix. We show that scarfff can compute the first 12 form factors for a molecule of 10 heavy atoms in approximately 5 s, opening the door to accurate, high-throughput material screening for optimal directional dark matter detector targets. Our code can perform the calculation in three independent ways, two semianalytical and one fully numeric, providing optimized methods for every precision goal.

United States

Benjamin Lillard

United Kingdom

Jack D. Shergold

Sweden

Carlos Blanco

Numerical method for the efficient calculation of scattering form factors

We address momentum entanglement in Higgs decays to weak boson pairs, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>H</mi><mo stretchy="false">→</mo><mi>W</mi><mi>W</mi><mo>,</mo><mi>Z</mi><mi>Z</mi></math>, by discretizing momentum space. The momenta of the two weak bosons are entangled, as well as the degrees of freedom in momentum and spin spaces. For <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>H</mi><mo stretchy="false">→</mo><mi>Z</mi><mi>Z</mi></math> in the four-lepton final state, we also estimate the statistical sensitivity of entanglement measures at the Large Hadron Collider and future upgrades. The discretization method introduced here is broadly applicable, offering a framework for studies of momentum entanglement at the energy frontier.

Spain

J.A. Aguilar-Saavedra

Momentum entanglement at colliders: The <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>H</mi><mo stretchy="false">→</mo><mi>W</mi><mi>W</mi><mo>,</mo><mi>Z</mi><mi>Z</mi></math> case

Wineglass wormholes mediate the nucleation of baby universes out of an asymptotically anti-de Sitter or flat spacetime. Upon materialization, the new universe naturally undergoes an inflationary phase. Here, we study the quantum state of tensor and probe scalar field fluctuations that these wormhole geometries prepare, finding that they reproduce the Bunch-Davies vacuum for short-wavelength modes but lead to deviations from Bunch-Davies on large scales. These deviations, which depend on the charge of the wormhole, cause a small shift as well as oscillations in the angular power spectrum generated by an ensuing inflationary phase, and thus provide a distinctive cosmological observable. The wormholes are supported by either axionic or magnetic charges. In the limit of vanishing charge, they undergo a topological transition after which they contain no-boundary instantons. We find that the small-charge limit suppresses deviations from the Bunch-Davies state for both scalar and tensor fluctuations, indicating that the topological transition is smooth.

Georgia

George Lavrelashvili

Germany

Jean-Luc Lehners

Quantum states prepared by wormholes: Long-wavelength deviations from the Bunch-Davies vacuum

We explore, for the first time in lattice QCD, the radiative decays to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi><mi>η</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi><msup><mi>η</mi><mo>′</mo></msup></math> of the <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>1</mn><mrow><mo>+</mo><mo>−</mo></mrow></msup></math> charmonium state, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>h</mi><mi>c</mi></msub></math>. This work expands upon a previous calculation of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math> decays to the same final states, incorporating novel technology to access the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>h</mi><mi>c</mi></msub></math> where it is an excited state and to separate the independent electric dipole and longitudinal form factors. Results for the radiative decay rates, computed on three-flavor lattices with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>π</mi></msub><mo>∼</mo><mn>391</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi></math>, show a suppression relative to experiment that is similar to that observed in the prior calculation of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mo stretchy="false">→</mo><mi>γ</mi><msup><mi>η</mi><mrow><mo stretchy="false">(</mo><mo>′</mo><mo stretchy="false">)</mo></mrow></msup></math>. The timelike <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>Q</mi><mn>2</mn></msup></math> dependence of both form factors together influence the Dalitz decays, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>h</mi><mi>c</mi></msub><mo stretchy="false">→</mo><msup><mo>ℓ</mo><mo>+</mo></msup><msup><mo>ℓ</mo><mo>−</mo></msup><msup><mi>η</mi><mrow><mo stretchy="false">(</mo><mo>′</mo><mo stretchy="false">)</mo></mrow></msup></math>, which are as yet unmeasured experimentally.

Australia

Mischa Batelaan

Jozef J. Dudek

Robert G. Edwards

Radiative decays of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>h</mi><mi>c</mi></msub></math> meson from lattice QCD

We conduct numerical simulations to map out the phase diagram and critical behavior of a lattice Higgs model composed of two massless staggered fermion fields forming a doublet under a global <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>S</mi><mi>U</mi><mo stretchy="false">(</mo><mn>2</mn><mo stretchy="false">)</mo></mrow></math> and coupled to a scalar field in the adjoint representation of the group. The scalar action consists of a potential comprising quadratic and quartic terms and a scalar kinetic term. At fixed quartic coupling we explore a two-dimensional parameter space finding a massless symmetric phase at weak coupling and a massive symmetric phase (SMG phase) at strong coupling. An intermediate antiferromagnetic phase separates these two regimes. These results are consistent with leading order weak and strong coupling expansions. We find that the critical lines bounding the intermediate phase merge at a unique point where all fermion bilinear condensates vanish but fermion susceptibilities diverge as nontrivial powers of the lattice size. We conjecture that this merged point corresponds to a multicritical point and may describe a phase consisting of a condensate of certain topological defects.

Nouman Butt

Simon Catterall

Gwen Hartshaw

Anna Hasenfratz

Searching for symmetric mass generation with staggered fermions in four dimensions

Within the framework of nonrelativistic quantum chromodynamics (NRQCD) factorization, we calculate the next-to-leading-order (NLO) QCD corrections to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>b</mi><mi>J</mi></mrow></msub><mo stretchy="false">→</mo><mi>J</mi><mo>/</mo><mi>ψ</mi><mo>+</mo><mi>γ</mi></math> with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>=</mo><mn>0</mn></math>, 1, 2. We determine all six independent helicity amplitudes, including the one-loop corrections to the quantum electrodynamics (QED) amplitude and the two-loop corrections to the QCD amplitude, and retain the interference between the QED and QCD amplitudes in the decay widths. The NLO corrections substantially enhance the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>b</mi><mn>0</mn></mrow></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>b</mi><mn>1</mn></mrow></msub></math> decay widths, while reducing the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>b</mi><mn>2</mn></mrow></msub></math> decay width by approximately 36%. Including the QED amplitude leads to sizable destructive interference for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>b</mi><mn>0</mn></mrow></msub></math> and an enhancement for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>b</mi><mn>2</mn></mrow></msub></math>, but has only a small effect on the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>b</mi><mn>1</mn></mrow></msub></math> decay width. Two treatments of photon fragmentation, based on the NRQCD matrix element and the experimentally determined <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math> decay constant, yield NLO unpolarized decay widths that agree at the few percent level or better. Using the decay constant scheme at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>μ</mi><mi>R</mi></msub><mo>=</mo><msub><mi>m</mi><mi>b</mi></msub></math>, we obtain NLO central branching fractions of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1.03</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>6</mn></mrow></msup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1.45</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1.99</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>6</mn></mrow></msup></math> for the three channels, respectively. The NLO corrections reduce the renormalization scale dependence, particularly for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>b</mi><mn>2</mn></mrow></msub></math>, although a sizable dependence remains for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>b</mi><mn>0</mn></mrow></msub></math>. At fixed <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>b</mi></msub></math>, the branching fractions decrease with increasing <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>r</mi><mo>=</mo><msub><mi>m</mi><mi>c</mi></msub><mo>/</mo><msub><mi>m</mi><mi>b</mi></msub></math>, more strongly for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>b</mi><mn>1</mn></mrow></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>b</mi><mn>2</mn></mrow></msub></math> than for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>b</mi><mn>0</mn></mrow></msub></math>. For <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>p</mi></math> collisions at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>14</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math> and an integrated luminosity of <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>, we estimate approximately <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1.9</mn><mo>×</mo><msup><mn>10</mn><mn>4</mn></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>4.8</mn><mo>×</mo><msup><mn>10</mn><mn>4</mn></msup></math> <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mo>ℓ</mo><mo>+</mo></msup><msup><mo>ℓ</mo><mo>−</mo></msup><mi>γ</mi></math> events from <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>b</mi><mn>0</mn></mrow></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>b</mi><mn>2</mn></mrow></msub></math> decays, respectively. Measurements with the existing Belle <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo></math> sample remain challenging because of the small expected yields. A substantially larger <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo></math> sample at Belle II would improve the prospects for observing these radiative decays.

China

Yu-Dong Zhang

Zai-Fu Jiang

Next-to-leading-order QCD corrections to the radiative decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>b</mi><mi>J</mi></mrow></msub><mo stretchy="false">→</mo><mi>J</mi><mo>/</mo><mi>ψ</mi><mo>+</mo><mi>γ</mi></math>

Left-right symmetric theories with generalized parity restrict the bare QCD angle to a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math>-conserving value and relate the physical strong-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> phase <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>θ</mi><mo stretchy="false">¯</mo></mover></math> to a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math>-odd parity-breaking parameter <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ε</mi></math>. We show that, in the Dirac-neutrino realization, imposing a sectorial reality condition on the Dirac lepton Yukawa matrices turns observable leptonic <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation from an independent input into a branch-dependent prediction. Parity reconstructs the right-handed leptonic mixing matrix, whereas leptonic reality requires it to be rephasing-equivalent to the complex conjugate of the left-handed one. For generic three-generation Yukawas, compatibility is equivalent to the vanishing of a single Jarlskog-type <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math>-odd invariant. In the physical Dirac hierarchy, for fixed oscillation data, mass ordering, and discrete leptonic branch, compatibility determines the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) Jarlskog invariant as a function of the lightest neutrino mass and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ε</mi></math>. We derive its leading analytic behavior and obtain the nonlinear compatibility branches numerically. In compressed mixed-sign Dirac-neutrino spectra, small signed mass sums can amplify a tiny parity deformation into order-one values of the normalized PMNS Jarlskog invariant, including maximal <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation. The corresponding quark reconstruction independently provides a calculable, branch-dependent conversion between <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ε</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>θ</mi><mo stretchy="false">¯</mo></mover></math>. Together, the leptonic and quark relations define a family of correlations among leptonic <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation, the absolute neutrino mass scale, and strong <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math>.

Croatia

Vladimir Tello

Strong <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> phase and the PMNS phase in Dirac left-right symmetry

The local solar gravitational potential forms a basin for ultralight dark matter (ULDM) with discrete energy levels. Even if barely populated, it introduces a new characteristic timescale in DM dynamics. This necessitates a generalization of the notion of coherence time. We find that, at long times, the phenomenon of “recoherence” emerges, whereby a subcomponent of ULDM exhibits a formally divergent coherence time. The fact that this generalized coherence time can significantly exceed the naive estimate implies an enhanced sensitivity for dark matter searches that accumulate data over extended observation periods.

Israel

Chaitanya Paranjape

Gilad Perez

Wolfram Ratzinger

Somasundaram Sankaranarayanan

Is the conventional picture of coherence time complete? Dark matter recoherence from substructures

In this paper, we study the renormalization of a three-dimensional quartic model on a compact connected Riemannian manifold with a boundary. We show that, in addition to the standard shift of the mass parameter, it is necessary to take into account boundary contributions involving singular coefficients. This indicates the need to extend the classical action within the framework of standard renormalization theory. The requirements of consistency regarding the gluing of manifolds lead to renormalization of an operator on the boundary.

Russia

A.V. Ivanov

Renormalization, cutoff, and gluing for a quartic model with boundary