China

Hao-Fu Zhu

Guo-Zhu Liu

Xufen Wu

Corrigendum to “Rapid cooling of the Cassiopeia A neutron star due to superfluid quantum criticality” [Physics Letters B 879 (2026) 140591]

We compute one-loop QCD corrections to the triple differential width of the inclusive decay $$ \overline{B}\to {X}_c\ell {\overline{\nu}}_{\ell } $$ including contributions from all relevant dimension-six operators in the Weak Effective Theory (WET), at leading power in the heavy quark expansion. Furthermore we derive for the first time up to order $$ \mathcal{O}\left({\alpha}_s\right) $$ analytic expressions for the first three moments of the distribution in the lepton energy, hadronic invariant mass and dilepton invariant mass, in the presence of beyond the Standard Model contributions from the WET.

Germany

Alexandre Carvunis

Italy

Gael Finauri

One-loop QCD corrections to $$ \overline{B}\to {X}_c\ell {\overline{\nu}}_{\ell } $$ in and beyond the Standard Model

An anisotropic Bianchi type-I cosmological model is examined in the framework of modified teleparallel gravity described by a general function $\textit{f}$($\textit{T}$, $\textit{B}$) of the torsion scalar and the boundary term. We consider the general cosmological solutions of the field equations obtained without imposing symmetry conditions at the level of the action. These solutions are employed to analyze the associated Noether symmetries and the structure of the corresponding symmetry algebras. In particular, we identify distinct classes of solutions admitting higher-dimensional Noether vector fields, whose dimensionality reflects enhanced geometrical invariance and leads to qualitatively different anisotropic cosmological behaviors. For representative cases, we investigate the geometrical evolution of the scale factors, relevant cosmological parameters, and the behavior of the effective energy density and anisotropic pressures. Our analysis shows that physically acceptable cosmological evolution arises only for restricted classes of solutions, thereby providing viability constraints on anisotropic dynamics in $\textit{f}$($\textit{T}$, $\textit{B}$) gravity.

Arshad Ali

Pakistan

Fiaz Hussain

General anisotropic cosmological solutions and physical viability in $\textit{f}$($\textit{T}$, $\textit{B}$) gravity

We demonstrate that a vector-like fourth family of quarks induces a genuine chiral enhancement in $\textit{b}$ → $\textit{sγ}$, which is absent in the Standard Model (SM). The coexistence of doublet and singlet states allows the chirality flip to occur inside the loop, leading to contributions proportional to the heavy vector-like mass. The resulting amplitude is enhanced by a factor $$ {\overline{\lambda}}_d{v}_H/{m}_b $$ , which can be as large as $$ \mathcal{O}(40) $$ for moderate Yukawa couplings. This leads to sizable deviation from the SM prediction even for $$ \mathcal{O}\left(\mathrm{TeV}\right) $$ vector-like quark masses and small mixing angles. We find that $$ \mathrm{Br}\left(\overline{B}\to {X}_s\gamma \right) $$ provides the most stringent constraint on this scenario among a wide range of precision observables.

Japan

Junichiro Kawamura

Yuji Omura

Chiral enhancement in the vector-like fourth family: case of $\textit{b}$ → $\textit{sγ}$

The Belle Collaboration has recently reported a measurement of the branching fraction for the semileptonic decay $ B^{-}\to\pi^{+}\pi^{-}\ell^{-}\bar\nu_\ell $ , with $ \ell=e $ or $\textit{μ}$. Using the newly available data across the full $ \pi\pi $ invariant-mass spectrum, we determine the non-resonant $ B\to\pi\pi $ transition form factors. We obtain a non-resonant branching fraction $ {\cal B}_N(B^{-}\to\pi^{+}\pi^{-}\ell^{-}\bar\nu_\ell)=(3.5\pm 1.4^{+4.3}_{-2.4})\times 10^{-5} $ . This result indicates that the non-resonant contribution can be comparable in magnitude to the resonant components and should not be treated as a negligible background in precision measurements. Our findings highlight the importance of dedicated experimental efforts at Belle II and LHCb to further probe the non-resonant contribution.

Yan-Li Wang

Xiao-Yu Hao

Yu-Kuo Hsiao

Semileptonic ${B^{-}\to\pi^{+}\pi^{-}\ell^{-}\bar\nu_\ell}$ decay over the full ${\pi\pi}$ invariant mass spectrum * Supported in part by the National Natural Science Foundation of China (12575101, 12175128)

The <math altimg='si1.svg'><msubsup><mn>3</mn><mn>1</mn><mo>&#8722;</mo></msubsup></math> state at an excitation energy of 2748 keV in the <italic>N</italic>=50 semi-magic 90Zr nucleus was investigated via safe Coulomb excitation in the 32S+ 90Zr system. The octupole transition strength, <math altimg='si7.svg'><mrow><mi>B</mi><mo stretchy='true'>(</mo><mi>E</mi><mn>3</mn><mo>;</mo><msubsup><mn>3</mn><mn>1</mn><mo>&#8722;</mo></msubsup><mo>&#8594;</mo><msubsup><mn>0</mn><mn>1</mn><mo>+</mo></msubsup><mo stretchy='true'>)</mo></mrow></math>, was extracted by fitting the measured <italic>&#947;</italic>-ray intensities using the semiclassical least-squares search codes <small-caps>gosia</small-caps> and <small-caps>gosia2</small-caps>. A pronounced <italic>E</italic>3 strength of <math altimg='si22.svg'><mrow><mn>19</mn><mo>.</mo><msubsup><mn>6</mn><mrow><mo>&#8722;</mo><mn>1.6</mn></mrow><mrow><mo>+</mo><mn>1.7</mn></mrow></msubsup></mrow></math> W.u. was obtained, indicating a collective octupole character for this state. State-of-the-art shell model calculations reproduce this result by describing the excitation as emergent collectivity rooted in microscopic configuration mixing, whereas pure harmonic vibrational models tend to overestimate the strength. In addition, the spectroscopic quadrupole moment of the <math altimg='si2.svg'><msubsup><mn>2</mn><mn>1</mn><mo>+</mo></msubsup></math> state in 90Zr was determined to be <math altimg='si23.svg'><mrow><mo>+</mo><mn>0.09</mn><mo>(</mo><mn>10</mn><mo>)</mo></mrow></math> <italic>e</italic>b, by normalizing the target excitation to the Coulomb-excitation intensities of the 32S projectile in a simultaneous analysis. This value is consistent with the near-spherical structure expected for a semi-magic nucleus. The results yield a coherent picture of collectivity in 90Zr, and are discussed in the context of the evolution of <italic>E</italic>3 strength along the stable Zr chain towards the <italic>N</italic>=56 octupole-magic neutron number.

Poland

India

P. Dey

A. Kundu

R. Palit

P.J. Napiorkowski

K. Yanase

N. Shimizu

Y. Utsuno

T. Inakura

E. Ideguchi

United States

U. Garg

M. Kumar Raju

Vishal Malik

V. Nanal

S. Pal

A. Sindhu

S. Thorat

First measurement of <math altimg='si7.svg'><mrow><mi>B</mi><mo stretchy='true'>(</mo><mi>E</mi><mn>3</mn><mo>;</mo><msubsup><mn>3</mn><mn>1</mn><mo>&#8722;</mo></msubsup><mo>&#8594;</mo><msubsup><mn>0</mn><mn>1</mn><mo>+</mo></msubsup><mo stretchy='true'>)</mo></mrow></math> in 90Zr through Coulomb excitation: Revisiting octupole collectivity in the Zr chain

Semileptonic $$b\rightarrow c\tau \bar{\nu }_{\tau }$$ decays are powerful probes of non-Standard-Model effects within an effective-field-theory (EFT) framework, but fully exploiting them in current and future data demands combinations that maximise sensitivity while controlling biases from Standard-Model-based modelling and from theory inputs that are shared, and therefore correlated, across analyses in different experiments. We present a first sensitivity study of a $\textit{combined}$ extraction of Wilson coefficients in $$\bar{B}\rightarrow D^{(*)}\tau \bar{\nu }_{\tau }$$ decays using LHCb- and Belle II-like analysis configurations. Detector simulations for signal and backgrounds are typically generated under Standard Model assumptions; if non-SM contributions are present, this can bias the fitted Wilson coefficients. In addition, hadronic inputs such as form-factor parameters of signal and background components are common across analyses, requiring a consistent treatment of fully correlated effects in combinations. To avoid repeating large-scale detector simulation for each EFT hypothesis, we use event-by-event reweighting to map simulated samples to arbitrary combinations of Wilson coefficients. We then compare a simultaneous fit across multiple $$\bar{B}\rightarrow D^{(*)}\tau \bar{\nu }_{\tau }$$ channels and datasets with a combination based on post-fit averages. Sharing Wilson coefficients and common form-factor parameters in the simultaneous fit reduces model-induced biases and improves sensitivity relative to independent fits, providing a robust and scalable strategy for precision EFT constraints in $$b\rightarrow c\tau \bar{\nu }_{\tau }$$ transitions using forthcoming LHCb and Belle II datasets.

Johannes Albrecht

Florian Bernlochner

Marco Colonna

Lorenz Gärtner

Switzerland

Abhijit Mathad

United Kingdom

Biljana Mitreska

Markus Prim

Ilias Tsaklidis

Joint LHCb–Belle II prospects to constrain new physics in $$B\rightarrow D^{(*)}\tau \nu $$

J.G. Wang

Z.C. Li

Z.Y. Zhang

Z.G. Gan

A.N. Andreyev

M.H. Huang

L. Ma

M.M. Zhang

H.B. Yang

C.L. Yang

Y.H. Qiang

Z.H. Li

X.Y. Huang

G. Xie

L. Zhu

H. Zhou

X. Zhang

J.H. Zheng

S.Y. Xu

Z. Zhao

L.C. Sun

F. Guan

X.L. Wu

W.X. Huang

Y.L. Tian

Y.S. Wang

J.Y. Wang

Z.W. Lu

Y. He

L.T. Sun

Z.Z. Ren

S.G. Zhou

Russia

V.K. Utyonkov

A.A. Voinov

Yu. S. Tsyganov

A.N. Polyakov

Corrigendum to “Decay properties of new isotopes 235Bk and 231Am” [Physics Letters B 875 (2026) 140365]

We investigate the $\textit{b}$ → $\textit{c}$ semileptonic sum rule in the presence of a massive sterile neutrino. Recent measurements of charged-current semitauonic $\textit{B}$-meson decays exhibit a ∼ 4$\textit{σ}$ deviation from the Standard Model predictions, whereas no such tension has been reported for the lowest-lying baryonic counterpart, the Λ decay. Since these decay rates are related through the sum rule, accommodating such a mismatch beyond the level of uncertainties is nontrivial. We revisit this issue by considering dimension-six operators involving a massive sterile neutrino, and evaluate the resulting violation of the sum rule. We find that the induced effect remains negligible compared with the current experimental uncertainties, further strengthening the sum rule as a consistency check for the experimental data.

Motoi Endo

Syuhei Iguro

Tim Kretz

Satoshi Mishima

$\textit{b}$ → $\textit{c}$ semileptonic sum rule: exploring a sterile neutrino loophole

We study the rates of two-body charmed-anticharmed baryonic <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mover accent="true"><mrow><mi>B</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mo stretchy="false">→</mo><msub><mrow><mi mathvariant="script">B</mi></mrow><mrow><mi>c</mi></mrow></msub><msub><mrow><mover accent="true"><mrow><mi mathvariant="script">B</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover></mrow><mrow><mi>c</mi></mrow></msub></mrow></math> decays using the topological amplitude approach. All amplitudes of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">→</mo><msub><mi mathvariant="script">B</mi><mi>c</mi></msub><mo stretchy="false">(</mo><msub><mover accent="true"><mn mathvariant="bold">3</mn><mo stretchy="false">¯</mo></mover><mi mathvariant="bold">f</mi></msub><mo stretchy="false">)</mo><msub><mover accent="true"><mi mathvariant="script">B</mi><mo stretchy="false">¯</mo></mover><mi>c</mi></msub><mo stretchy="false">(</mo><msub><mn mathvariant="bold">3</mn><mi mathvariant="bold">f</mi></msub><mo stretchy="false">)</mo></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="script">B</mi><mi>c</mi></msub><mo stretchy="false">(</mo><msub><mn mathvariant="bold">6</mn><mi mathvariant="bold">f</mi></msub><mo stretchy="false">)</mo><msub><mover accent="true"><mi mathvariant="script">B</mi><mo stretchy="false">¯</mo></mover><mi>c</mi></msub><mo stretchy="false">(</mo><msub><mn mathvariant="bold">3</mn><mi mathvariant="bold">f</mi></msub><mo stretchy="false">)</mo></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="script">B</mi><mi>c</mi></msub><mo stretchy="false">(</mo><msub><mover accent="true"><mn mathvariant="bold">3</mn><mo stretchy="false">¯</mo></mover><mi mathvariant="bold">f</mi></msub><mo stretchy="false">)</mo><msub><mover accent="true"><mi mathvariant="script">B</mi><mo stretchy="false">¯</mo></mover><mi>c</mi></msub><mo stretchy="false">(</mo><msub><mover accent="true"><mn mathvariant="bold">6</mn><mo stretchy="false">¯</mo></mover><mi mathvariant="bold">f</mi></msub><mo stretchy="false">)</mo></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="script">B</mi><mi>c</mi></msub><mo stretchy="false">(</mo><msub><mn mathvariant="bold">6</mn><mi mathvariant="bold">f</mi></msub><mo stretchy="false">)</mo><msub><mover accent="true"><mi mathvariant="script">B</mi><mo stretchy="false">¯</mo></mover><mi>c</mi></msub><mo stretchy="false">(</mo><msub><mover accent="true"><mn mathvariant="bold">6</mn><mo stretchy="false">¯</mo></mover><mi mathvariant="bold">f</mi></msub><mo stretchy="false">)</mo></math> decays are decomposed topologically. SU(3) breaking effects on these amplitudes, depending on the position of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>s</mi></math>-quark line, are modeled. Using existing data as input, we obtained the following results: (i) In the low-lying <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">→</mo><msub><mi mathvariant="script">B</mi><mi>c</mi></msub><mo stretchy="false">(</mo><msub><mover accent="true"><mn mathvariant="bold">3</mn><mo stretchy="false">¯</mo></mover><mi mathvariant="bold">f</mi></msub><mo stretchy="false">)</mo><msub><mover accent="true"><mi mathvariant="script">B</mi><mo stretchy="false">¯</mo></mover><mi>c</mi></msub><mo stretchy="false">(</mo><msub><mn mathvariant="bold">3</mn><mi mathvariant="bold">f</mi></msub><mo stretchy="false">)</mo></math> decays, we find that the exchange diagram is sizable. Furthermore, there is a large cancellation between internal <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi></math>-tree and exchange-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi></math>-tree amplitudes. The SU(3) breaking is sizable, 35% SU(3) breaking effects are needed, and they work differently in different amplitudes. Namely, the internal <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi></math>-tree amplitude is enlarged, while the exchange-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi></math>-tree amplitude is reduced. The rates of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">→</mo><msub><mi mathvariant="script">B</mi><mi>c</mi></msub><mo stretchy="false">(</mo><msub><mover accent="true"><mn mathvariant="bold">3</mn><mo stretchy="false">¯</mo></mover><mi mathvariant="bold">f</mi></msub><mo stretchy="false">)</mo><msub><mover accent="true"><mi mathvariant="script">B</mi><mo stretchy="false">¯</mo></mover><mi>c</mi></msub><mo stretchy="false">(</mo><msub><mn mathvariant="bold">3</mn><mi mathvariant="bold">f</mi></msub><mo stretchy="false">)</mo></math> decays with excited <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="script">B</mi><mi>c</mi></msub><mo stretchy="false">(</mo><msub><mover accent="true"><mn mathvariant="bold">3</mn><mo stretchy="false">¯</mo></mover><mi mathvariant="bold">f</mi></msub><mo stretchy="false">)</mo></math>, such as <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="normal">Λ</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>2595</mn><msup><mo stretchy="false">)</mo><mo>+</mo></msup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="normal">Ξ</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>2790</mn><msup><mo stretchy="false">)</mo><mrow><mo>+</mo><mo>,</mo><mn>0</mn></mrow></msup></math>, are also studied. (ii) The <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">→</mo><msub><mi mathvariant="script">B</mi><mi>c</mi></msub><mo stretchy="false">(</mo><msub><mn mathvariant="bold">6</mn><mi mathvariant="bold">f</mi></msub><mo stretchy="false">)</mo><msub><mover accent="true"><mi mathvariant="script">B</mi><mo stretchy="false">¯</mo></mover><mi>c</mi></msub><mo stretchy="false">(</mo><msub><mn mathvariant="bold">3</mn><mi mathvariant="bold">f</mi></msub><mo stretchy="false">)</mo></math> decays, with low-lying <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mover accent="true"><mi mathvariant="script">B</mi><mo stretchy="false">¯</mo></mover><mi>c</mi></msub><mo stretchy="false">(</mo><msub><mn mathvariant="bold">3</mn><mi mathvariant="bold">f</mi></msub><mo stretchy="false">)</mo></math> and low-lying and excited <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="script">B</mi><mi>c</mi></msub><mo stretchy="false">(</mo><msub><mn mathvariant="bold">6</mn><mi mathvariant="bold">f</mi></msub><mo stretchy="false">)</mo></math> baryons, such as <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="normal">Σ</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>2520</mn><msup><mo stretchy="false">)</mo><mrow><mo>+</mo><mo>,</mo><mn>0</mn></mrow></msup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="normal">Ξ</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>2645</mn><msup><mo stretchy="false">)</mo><mrow><mo>+</mo><mo>,</mo><mn>0</mn></mrow></msup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="normal">Ω</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>2770</mn><msup><mo stretchy="false">)</mo><mn>0</mn></msup></math>, are studied with some predictions on rates obtained. Furthermore, as the excited states are spin-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>3</mn><mo>/</mo><mn>2</mn></mrow></math> states, some of their rates are highly suppressed by the kinematic factor. (iii) The <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">→</mo><msub><mi mathvariant="script">B</mi><mi>c</mi></msub><mo stretchy="false">(</mo><msub><mover accent="true"><mn mathvariant="bold">3</mn><mo stretchy="false">¯</mo></mover><mi mathvariant="bold">f</mi></msub><mo stretchy="false">)</mo><msub><mover accent="true"><mi mathvariant="script">B</mi><mo stretchy="false">¯</mo></mover><mi>c</mi></msub><mo stretchy="false">(</mo><msub><mover accent="true"><mn mathvariant="bold">6</mn><mo stretchy="false">¯</mo></mover><mi mathvariant="bold">f</mi></msub><mo stretchy="false">)</mo></math> decays with low-lying charmed-anticharmed baryons are studied with some predictions on rates obtained. (iv) Uncertainties in most predicted rates are large, reflecting our current poor understanding of the related SU(3) breaking effects. Measuring these rates can provide very useful information about these effects.

Chun-Khiang Chua

Two-body charmed-anticharmed baryonic <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math> decays