Using data samples collected by the Belle and Belle II experiments at the Υ(4$\textit{S}$) resonance with integrated luminosities of 571 fb and 365 fb , respectively, we measure the pseudoscalar $\textit{B}$-meson mass difference to be $\textit{m}$($\textit{B}$ ) − $\textit{m}$($\textit{B}$ ) = (0$\textit{.}$495 ± 0$\textit{.}$024 ± 0$\textit{.}$005) MeV/$\textit{c}$ . The results are based on a simultaneous fit to the variable $${\overline{M} }_{bc}$$ , which is related to the $\textit{B}$ momentum, for $\textit{B}$ and $\textit{B}$ candidates; and to the energy dependence of $$\mathcal{R}=\sigma ({e}^{+}{e}^{-}\to {B}^{0}{\overline{B} }^{0}) / \sigma ({e}^{+}{e}^{-}\to {B}^{+}{B}^{-})$$ , which is measured using changes in the average center-of-mass energy over the data taking periods. The phase-space hypothesis $$\mathcal{R}={({p}_{{B}^{0}} /{p}_{{B}^{+}})}^{3}$$ , upon which previous measurements rely, is strongly disfavored by our fit; the measured mass-difference value for the phase-space hypothesis also differs significantly from our measurement. We constrain $$\mathcal{R}$$ in a broader energy range than covered by the direct measurement and extract the energy dependence of $$\mathcal{R}$$ in the range from the $$B\overline{B }$$ threshold up to 10.59 GeV. We interpret the results using a phenomenological model and constrain the parameters of the $$B\overline{B }$$ potential in the isovector channel.

M. Abumusabh

I. Adachi

L. Aggarwal

H. Ahmed

Y. Ahn

H. Aihara

N. Akopov

S. Alghamdi

M. Alhakami

A. Aloisio

N. Althubiti

K. Amos

N. Anh Ky

C. Antonioli

D. Asner

H. Atmacan

T. Aushev

R. Ayad

V. Babu

N. Baghel

S. Bahinipati

P. Bambade

Sw. Banerjee

M. Barrett

M. Bartl

J. Baudot

A. Beaubien

F. Becherer

J. Becker

J. Bennett

F. Bernlochner

V. Bertacchi

M. Bertemes

E. Bertholet

M. Bessner

S. Bettarini

V. Bhardwaj

F. Bianchi

T. Bilka

D. Biswas

D. Bodrov

A. Bondar

G. Bonvicini

J. Borah

A. Boschetti

A. Bozek

M. Bračko

P. Branchini

R. Briere

T. Browder

A. Budano

S. Bussino

Q. Campagna

M. Campajola

G. Casarosa

C. Cecchi

P. Chang

P. Cheema

L. Chen

B. Cheon

C. Cheshta

H. Chetri

K. Chilikin

J. Chin

K. Chirapatpimol

H.E. Cho

K. Cho

S.J. Cho

S.K. Choi

S. Choudhury

S. Chutia

J. Colorado-Caicedo

I. Consigny

L. Corona

J. Cui

E. Cruz-Burelo

S. Motte

G. Marino

G. Nardo

G. Pietro

R. Sangro

M. Destefanis

S. Dey

A. Canto

Z. Doležal

I. Domínguez Jiménez

T. Dong

X. Dong

M. Dorigo

G. Dujany

P. Ecker

J. Eppelt

R. Farkas

P. Feichtinger

T. Ferber

T. Fillinger

C. Finck

G. Finocchiaro

F. Forti

B. Fulsom

Measurements of the mass difference $\textit{m}$($\textit{B}$ 0) $\textit{− m}$($\textit{B}$ +) and the energy dependence of the cross-section ratio $$\sigma ({e}^{+}{e}^{-}\to {B}^{0}{\overline{B} }^{0})/\sigma ({e}^{+}{e}^{-}\to {B}^{+}{B}^{-})$$ at Belle and Belle II

We investigate the gluon gravitational form factors of the $\textit{π}$, $\textit{N}$, $\textit{ρ}$, and ∆ using lattice QCD data at $\textit{m}$ ≈ 450 MeV and $\textit{m}$ ≈ 170 MeV. We base the analysis on fits to a simple $\textit{σ}$/$\textit{f}$ (500)-meson pole, supplemented by a polynomial background term. The fitted residues agree with predictions from dilaton effective theory, in which the $\textit{σ}$-meson acts as the dilaton, the pseudo Goldstone boson of spontaneously broken scale symmetry. We derive new dilaton-based predictions for the $\textit{ρ}$- and ∆-gravitational form factors, and comment on the $\textit{η}$ - and $\textit{η}$ -form factors in the context of the dilaton interpretation. These results reinforce our earlier findings, based on lattice total (quark and gluon) gravitational form factors, and provide further evidence that QCD dynamics may be governed by an infrared fixed point.

United Kingdom

not found

Roy Stegeman

Roman Zwicky

Gluon gravitational $\textit{D}$-form factor: the $\textit{σ}$-meson as a dilaton confronted with lattice data II

Non-local interactions naturally arise in the ADM formalism after solving the constraint equations and substituting their solutions back into the action. However, the effects of these non-local operators on loop corrections to cosmological correlators remain largely unexplored. Extending the analysis of [1], in this work we compute the 1-loop bispectrum during slow-roll inflation, including the inverse-Laplacian operators present at cubic and quartic order in the ADM action (in the spatially flat gauge). These non-local vertices introduce non-trivial angular dependencies that significantly complicate the evaluation of loop integrals. We find that the diagrammatic rules of [1] for identifying poles and branch cuts in correlators without explicit integration remain valid even in the presence of such non-local interactions. Finally, we derive the flat-space limit of the 1-loop inflationary correlator and verify it with explicit examples, thereby establishing a direct correspondence between its leading total-energy singularities ($\textit{ω}$ → 0) and the flat-space scattering amplitude.

India

Elaf Ansari

Supritha Bhowmick

Diptimoy Ghosh

Singularities in cosmological loop correlators. Part II. Non local interactions and flat space limits

We continue the investigation of symmetries and anomalies of $\textit{T}$[$\textit{M}$] theories obtained by compactifying 6d SCFTs on an internal manifold $\textit{M}$. We extend the notion of “polarizations on a manifold $\textit{M}$” to cases where $\textit{M}$ may have boundaries or defects. Through examples with $\textit{M}$ of dimension two, three, and four, we illustrate recurring themes in compactifications — for instance, the important roles played by Kaluza-Klein modes, and how the generalized symmetries (including higher-group and non-invertible ones) of $\textit{T}$[$\textit{M}$], together with their anomalies, arise from non-trivial combinations of the parent 6d symmetries and the geometric structures of the internal manifold. For each dimension, we also focus on several topics that are especially interesting in that setting. These include: for 2-manifolds, the geometry of the “full moduli space” of $\textit{T}$[$\textit{M}$ ] and its interaction with polarizations and symmetries; for 3-manifolds, the effect of torsion in homology on the spectrum of line operators in $\textit{T}$[$\textit{M}$ ], together with applications to the study of quantum invariants such as $$ {\hat{Z}}_a\left({M}_3,q\right) $$ ; and for 4-manifolds, predictions for VOA[$\textit{M}$ ] following from symmetries of $\textit{T}$[$\textit{M}$ ], as well as the construction of a new invariant of 4-manifolds that depends on two “$\textit{q}$-parameters.” Along the way, we discuss a range of topics that are of independent interest, such as how non-invertible symmetries in higher dimensions can become invertible under compactification, how to classify defects in quantum field theory via their response to a change of framing, and the interplay between $$ {\hat{Z}}_a $$ and volume conjectures.

United States

Sergei Gukov

Po-Shen Hsin

Denmark

Du Pei

Sunghyuk Park

Generalized global symmetries of $\textit{T}$[$\textit{M}$] theories. Part II

Minimal flavor violation (MFV) provides a compelling framework for exploring physics beyond the Standard Model, in which new QCD-singlet fields transforming under the global <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>SU</mi><mo stretchy="false">(</mo><mn>3</mn><msup><mo stretchy="false">)</mo><mn>3</mn></msup></math> quark flavor symmetry can naturally be stable and act as dark matter (DM) candidates. We show that the DM–MFV framework naturally accommodates the excess in either <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>π</mi><mo>+</mo></msup><mi>ν</mi><mover accent="true"><mi>ν</mi><mo stretchy="false">¯</mo></mover></math> or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>K</mi><mo>+</mo></msup><mi>ν</mi><mover accent="true"><mi>ν</mi><mo stretchy="false">¯</mo></mover></math>, while a unified explanation of both channels simultaneously cannot be achieved within a minimal setup containing only a single dark matter multiplet with nearly degenerate masses. Overall, our findings underscore the intricate interplay between MFV-based model building, flavored dark matter scenarios, and precision flavor experiments, highlighting flavored dark matter as a framework that is both theoretically robust and experimentally testable.

Italy

Federico Mescia

South Korea

Japan

Shohei Okawa

CERN

Joel Swallow

France

Claudio Toni

Dark matter emission at Belle II and NA62 in the minimal flavor violation framework

While electron and muon dipole moments are well-established precision probes of physics beyond the standard model, it is notoriously challenging to test realistic new physics (NP) scenarios for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>τ</mi></math> lepton. Constructing suitable asymmetries in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup><mo stretchy="false">→</mo><msup><mrow><mi>τ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>τ</mi></mrow><mrow><mo>−</mo></mrow></msup></mrow></math> has emerged as a promising such avenue, providing access to the electric and magnetic dipole moment once a polarized electron beam is available, e.g., with the proposed polarization upgrade of the SuperKEKB <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup></math> collider. However, this interpretation relies on an effective-field-theory (EFT) argument that only applies if the NP scale is large compared to the center-of-mass energy. In this Letter, we address the consequences of the asymmetry measurements in the case of light NP, using light spin-0 and spin-1 bosons as test cases, to show how results can again be interpreted as constraints on dipole moments, albeit in a model-dependent manner, and how the decoupling to the EFT limit proceeds in these cases. In particular, we observe that the imaginary parts generated by light new particles can yield nonvanishing asymmetries even without electron polarization, which can again be interpreted as constraints on the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>τ</mi></math> anomalous magnetic moment. This proposed measurement, thus, presents a novel opportunity for NP searches that can be realized already with present data at Belle II.

Switzerland

Martin Hoferichter

Gabriele Levati

Light New Physics and the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>τ</mi></math> Lepton Dipole Moments: Prospects at Belle II

Traditional seesaw mechanisms provide an elegant theoretical framework in explaining the tiny yet nonzero masses of neutrinos. Nevertheless, they face significant challenges in experimental searches, primarily because the energy scale associated with the seesaw mechanism is too high to be directly reached by terrestrial experiments. In this paper, we explore the gravitational waves (GWs) generated via graviton bremsstrahlung during the decay of seesaw particles in the early Universe. Specifically, we compute the GW spectrum resulting from the decay of the Higgs triplet within the type-II seesaw model. Our results demonstrate that the resulting GW spectrum depends sensitively on the mass of the Higgs triplet and its couplings to the Standard Model Higgs doublet and the left-handed lepton doublets. The detection of such a high-frequency GW background could offer a unique experimental window into the seesaw mechanism and provide indirect evidence for its validity.

China

Yonghua Wang

Wei Chao

Testing the type-II seesaw mechanism with gravitational waves

We discuss spontaneous Leptogenesis in the Type II Seesaw model of neutrino masses featuring an electroweak triplet scalar $\textit{T}$ in a coherent pseudo Nambu-Goldstone boson (pNGB) background. In the “wash-in” scenario the inverse decays of Higgs bosons to $\textit{T}$ generate a chemical potential for the triplet, that is then transmitted to the lepton sector via the leptonic decays of $\textit{T}$. Our mechanism works with a single triplet, that can be as light as 1 TeV, and has a vacuum expectation value $\textit{v}$ in the window $$ \mathcal{O}\left(1\ \textrm{keV}\right) $$ < $\textit{v}$ < $$ \mathcal{O}\left(1\ \textrm{MeV}\right) $$ . This range of $\textit{v}$ can lead to appreciable decays of the triplet’s doubly charged component into both same sign di-leptons and same sign pairs of $\textit{W}$-bosons, which could potentially allow for an experimental distinction from a recently proposed inflationary Type II Seesaw Affleck-Dine scenario preferring the leptonic mode. In the “singlet-doublet-triplet Majoron” UV-completion of the Type II Seesaw model, the required pNGB is automatically included in the form of the Majoron, that originates from the phase of the lepton number breaking singlet scalar. The coherent motion of the Majoron can furthermore explain the dark matter relic abundance via the kinetic misalignment mechanism. Cogenesis of dark matter and the baryon asymmetry can work for a lepton number breaking scale of $$ \mathcal{O}\left({10}^5\ \textrm{GeV}\right) $$ < $\textit{v}$ < $$ \mathcal{O}\left({10}^8\ \textrm{GeV}\right) $$ and a Majoron mass of $$ \mathcal{O}\left(1\ \textrm{eV}\right) $$ > $\textit{m}$ > $$ \mathcal{O}\left(1\ \upmu \textrm{eV}\right) $$ .

Spain

Maximilian Berbig

Type II Seesaw Leptogenesis in a Majoron background

Generic solutions are studied in Einstein-scalar gravity in an ansatz that can interpolate between de Sitter and Anti-de Sitter regimes. The scalar potential is arbitrary. All solutions are determined by their end-points in the scalar field space. All such end-points are classified. This provides a complete classification and characterization of the full space of regular solutions. It is shown that there are no regular (Centaur) solutions that interpolate between an AdS boundary and a dS interior, within our ansatz, when $\textit{d >}$ 2. This no-go theorem persists in the presence of multiple scalar fields with a non-trivial field space metric. The Gubser classification of regular solutions is also upgraded to include cases that are not Lorentz invariant and do not contain AdS boundaries.

Greece

Elias Kiritsis

Romania

Sergio Morales-Tejera

Christopher Rosen

de Sitter versus Anti de Sitter flows and the (super)gravity landscape. Part II

We study the processes $\textit{χ}$ $\textit{ ω}$ and $\textit{χ}$ ($\textit{π}$ $\textit{π}$ $\textit{π}$ ) ($\textit{J}$ = 0, 1, 2) at center-of-mass energies $$\sqrt{s}$$ from 10.73 to 11.02 GeV using a 142$\textit{.}$5 fb data sample collected with the Belle detector at the KEKB asymmetric-energy $\textit{e}$ $\textit{e}$ collider; and at $$\sqrt{s}\sim 10.75$$ GeV using a 19$\textit{.}$8 fb sample collected with Belle II at SuperKEKB. We find that the Υ(10753) state decays into $\textit{χ}$ $\textit{ ω}$ but not into $\textit{χ}$ ($\textit{π}$ $\textit{π}$ $\textit{π}$ ) , while the Υ(10860) state, in contrast, decays into $\textit{χ}$ ($\textit{π}$ $\textit{π}$ $\textit{π}$ ) but not into $\textit{χ}$ $\textit{ ω}$. The mass and width of the Υ(10753) state are measured to be (10756$\textit{.}$1 ± 3$\textit{.}$4(stat$\textit{.}$) ± 2$\textit{.}$7(syst$\textit{.}$)) MeV/$\textit{c}$ and (32$\textit{.}$2 ± 11$\textit{.}$3(stat$\textit{.}$) ± 14$\textit{.}$9(syst$\textit{.}$)) MeV. The products of the partial width to $\textit{e}$ $\textit{e}$ and branching fractions for Υ(10753) $\textit{→ χ}$ $\textit{ω}$ and Υ(10753) $\textit{→ χ}$ $\textit{ω}$ are (1$\textit{.}$57 $\textit{±}$ 0$\textit{.}$27(stat$\textit{.}$) $\textit{±}$ 0$\textit{.}$22(syst$\textit{.}$)) eV and (1$\textit{.}$39 $\textit{±}$ 0$\textit{.}$41(stat$\textit{.}$) $\textit{±}$ 0$\textit{.}$33(syst$\textit{.}$)) eV.

M. Angelsmark

V. Aushev

M. Aversano

H. Bae

A. Baur

B. Bhuyan

A. Bobrov

A. Bolz

J. Cerasoli

M.C. Chang

R. Cheaib

J. Cochran

R. Dhamija

F. Capua

J. Dingfelder

D. Dossett

K. Dugic

D. Epifanov

A. Fodor

Improved measurement of Born cross sections for $\textit{χ}$ $\textit{bJ}$ $\textit{ ω}$ and $\textit{χ}$ $\textit{bJ}$ ($\textit{π}$ + $\textit{π}$ $\textit{−}$ $\textit{π}$ 0)non$\textit{−ω}$ ($\textit{J}$ = 0, 1, 2) at Belle and Belle II