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.

China

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)

<p>A search for resonant structures in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi><mo>+</mo><mi>ψ</mi><mo stretchy="false">(</mo><mn>2</mn><mi mathvariant="normal">S</mi><mo stretchy="false">)</mo></mrow></math> mass spectrum is performed using proton-proton collision data at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>, corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>140</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>, recorded by the ATLAS experiment at the LHC. The decay channels of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mo>+</mo><mi>ψ</mi><mrow><mo stretchy="false">(</mo><mn>2</mn><mi mathvariant="normal">S</mi><mo stretchy="false">)</mo></mrow><mo stretchy="false">→</mo><mn>4</mn><mi>μ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mo>+</mo><mi>ψ</mi><mrow><mo stretchy="false">(</mo><mn>2</mn><mi mathvariant="normal">S</mi><mo stretchy="false">)</mo></mrow><mo stretchy="false">→</mo><mn>4</mn><mi>μ</mi><mo>+</mo><mn>2</mn><mi>π</mi></math> are analyzed. An excess near 6.9 GeV is observed in both channels with a combined significance of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>8.9</mn><mi>σ</mi></mrow></math>. No significant signal is observed near 7.2 GeV, and an upper limit on its yield relative to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>X</mi><mo stretchy="false">(</mo><mn>6900</mn><mo stretchy="false">)</mo></math> is provided. A simultaneous fit with the di-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math> channel is carried out under assumptions regarding the resonance interferences, yielding a ratio of the partial decay widths between the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mo>+</mo><mi>ψ</mi><mrow><mo stretchy="false">(</mo><mn>2</mn><mi mathvariant="normal">S</mi><mo stretchy="false">)</mo></mrow></math> and di-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math> channels of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1.08</mn><mo>±</mo><mn>0.2</mn><msubsup><mn>0</mn><mrow><mo>−</mo><mn>0.17</mn></mrow><mrow><mo>+</mo><mn>0.40</mn></mrow></msubsup></math> for the resonance near 6.9 GeV.</p>

France

G. Aad

Norway

E. Aakvaag

United States

B. Abbott

United Arab Emirates

S. Abdelhameed

Germany

K. Abeling

N.J. Abicht

S.H. Abidi

M. Aboelela

Morocco

A. Aboulhorma

Israel

H. Abramowicz

Y. Abulaiti

Italy

B.S. Acharya

A. Ackermann

C. Adam Bourdarios

Poland

L. Adamczyk

S.V. Addepalli

United Kingdom

M.J. Addison

J. Adelman

Türkiye

A. Adiguzel

T. Adye

A.A. Affolder

Y. Afik

Spain

M.N. Agaras

A. Aggarwal

Romania

C. Agheorghiesei

F. Ahmadov

S. Ahuja

X. Ai

G. Aielli

A. Aikot

M. Ait Tamlihat

B. Aitbenchikh

M. Akbiyik

Sweden

T.P.A. Åkesson

A.V. Akimov

Japan

D. Akiyama

N.N. Akolkar

S. Aktas

G.L. Alberghi

Canada

J. Albert

Switzerland

U. Alberti

P. Albicocco

G.L. Albouy

S. Alderweireldt

Z.L. Alegria

CERN

M. Aleksa

I.N. Aleksandrov

C. Alexa

Greece

T. Alexopoulos

F. Alfonsi

M. Algren

M. Alhroob

Czechia

B. Ali

H.M.J. Ali

S. Ali

S.W. Alibocus

South Africa

M. Aliev

G. Alimonti

W. Alkakhi

C. Allaire

B.M.M. Allbrooke

D.R. Allen

J.S. Allen

J.F. Allen

P.P. Allport

A. Aloisio

Argentina

F. Alonso

C. Alpigiani

Z.M.K. Alsolami

A. Alvarez Fernandez

M. Alves Cardoso

M.G. Alviggi

M. Aly

Brazil

Y. Amaral Coutinho

A. Ambler

C. Amelung

M. Amerl

C.G. Ames

T. Amezza

D. Amidei

B. Amini

K. Amirie

A. Amirkhanov

Portugal

S.P. Amor Dos Santos

K.R. Amos

D. Amperiadou

S. An

C. Anastopoulos

T. Andeen

J.K. Anders

A.C. Anderson

A. Andreazza

S. Angelidakis

A. Angerami

A.V. Anisenkov

A. Annovi

C. Antel

E. Antipov

M. Antonelli

Observation of structures in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mo>+</mo><mi>ψ</mi><mo stretchy="false">(</mo><mn>2</mn><mi>S</mi><mo stretchy="false">)</mo></math> mass spectrum with the ATLAS detector

Arnau Bas i Beneito

Slovenia

Svjetlana Fajfer

Alexey Petrov

Erratum: New avenues for $\textit{|}$∆$\textit{B|}$ = 2 processes beyond neutron-antineutron oscillations

We calculate inclusive $\textit{B}$-meson decay rates in the Mesogenesis framework — a model explaining baryogenesis and the existence of dark matter — using the Heavy Quark Expansion (HQE), up to the dimension-six two-quark Darwin term. By systematically studying the power-suppressed contributions, we identify regions of parameter space where subleading terms exceed the leading contribution, i.e., the free $\textit{b}$-quark decay, highlighting the limits of the HQE in this BSM scenario. This behavior is reminiscent of the Standard Model only under artificially heavy charm masses, and can be used to study the HQE close to its breakdown. We further update the lower bounds on the exclusive decay mode $\textit{B}$ → $\textit{p}$ $\textit{ψ}$ by incorporating the fully HQE-corrected inclusive width in the ratio Γ $\textit{/}$Γ . Extending the analysis from total decay rates to the lifetime ratio $\textit{τ}$($\textit{B}$ )$\textit{/τ}$($\textit{B}$ ), we find no additional constraints on the couplings beyond existing collider bounds, consistent with analogous results for $\textit{τ}$($\textit{B}$ )$\textit{/τ}$($\textit{B}$ ). We further compare the sensitivity of both lifetime ratios.

Ali Mohamed

Are subleading effects really subleading? $\textit{B}$-meson decays in mesogenesis

<p>We report a measurement of the branching fraction for the leptonic decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>μ</mi><mo>+</mo></msup><msub><mi>ν</mi><mi>μ</mi></msub></math>. This work presents the first <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>μ</mi><mo>+</mo></msup><msub><mi>ν</mi><mi>μ</mi></msub></math> result using Belle II data, an updated Belle measurement that supersedes the previous result, and their combination, which yields the most precise search to date. The analysis is based on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1076</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> of <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> collision data collected at a center-of-mass energy of 10.58 GeV with the Belle and Belle II detectors at the KEKB and SuperKEKB colliders, respectively. We measure <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>μ</mi><mo>+</mo></msup><msub><mi>ν</mi><mi>μ</mi></msub><mo stretchy="false">)</mo><mo>=</mo><mspace linebreak="goodbreak"></mspace><mo stretchy="false">(</mo><mn>4.4</mn><mo>±</mo><mn>1.9</mn><mo>±</mo><mn>1.0</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup></math>, where the first uncertainty is statistical and the second systematic. The observed significance relative to the background-only hypothesis is 2.4 standard deviations. We set a 90% confidence level upper limit of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>μ</mi><mo>+</mo></msup><msub><mi>ν</mi><mi>μ</mi></msub><mo stretchy="false">)</mo><mo>&lt;</mo><mn>6.7</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup></math> using a frequentist approach and a 90% credibility level upper limit of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>μ</mi><mo>+</mo></msup><msub><mi>ν</mi><mi>μ</mi></msub><mo stretchy="false">)</mo><mo>&lt;</mo><mn>7.2</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup></math> using a Bayesian approach. These are the most stringent limits to date. The result is interpreted as an exclusion region in the parameter space of type II and type III two-Higgs-doublet models. We search for stable sterile neutrinos with masses <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>N</mi></msub><mo>∈</mo><mo stretchy="false">[</mo><mn>0</mn><mo>,</mo><mn>1.5</mn><mo stretchy="false">]</mo><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>. No signal is observed, and the resulting exclusion on the squared mixing parameter <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><msub><mi>U</mi><mrow><mi>μ</mi><mi>N</mi></mrow></msub><msup><mo stretchy="false">|</mo><mn>2</mn></msup></math> provides improvement over previous limits. We report a measurement of the partial branching fraction of semileptonic <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><msub><mi>X</mi><mi>u</mi></msub><mo>ℓ</mo><msub><mi>ν</mi><mo>ℓ</mo></msub></math> decays with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>p</mi><mi>μ</mi><mi>B</mi></msubsup><mo>&gt;</mo><mn>2.2</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>, obtaining <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Δ</mi><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><mi>B</mi><mo stretchy="false">→</mo><msub><mi>X</mi><mi>u</mi></msub><mo>ℓ</mo><msub><mi>ν</mi><mo>ℓ</mo></msub><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">(</mo><mn>2.72</mn><mo>±</mo><mn>0.05</mn><mo>±</mo><mn>0.29</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup></math>. We present a model-dependent study of weak annihilation decays using the muon momentum spectrum. We observe a signal of 2.4 standard deviations above the background-only hypothesis in regions where the distribution resembles that of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><msub><mi>X</mi><mi>u</mi></msub><mo>ℓ</mo><msub><mi>ν</mi><mo>ℓ</mo></msub></math> decays.</p>

M. Abumusabh

I. Adachi

K. Adamczyk

L. Aggarwal

H. Ahmed

Y. Ahn

H. Aihara

N. Akopov

S. Alghamdi

M. Alhakami

N. Althubiti

K. Amos

N. Anh Ky

C. Antonioli

D.M. Asner

H. Atmacan

T. Aushev

R. Ayad

V. Babu

H. Bae

N.K. Baghel

S. Bahinipati

P. Bambade

Sw. Banerjee

M. Barrett

M. Bartl

J. Baudot

A. Beaubien

F. Becherer

J. Becker

J.V. Bennett

F.U. Bernlochner

V. Bertacchi

M. Bertemes

E. Bertholet

M. Bessner

S. Bettarini

F. Bianchi

T. Bilka

D. Biswas

A. Bobrov

D. Bodrov

A. Bondar

G. Bonvicini

J. Borah

A. Boschetti

A. Bozek

M. Bračko

P. Branchini

R.A. Briere

T.E. Browder

A. Budano

S. Bussino

Q. Campagna

M. Campajola

L. Cao

G. Casarosa

C. Cecchi

P. Chang

P. Cheema

L. Chen

Study of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>μ</mi><mo>+</mo></msup><msub><mi>ν</mi><mi>μ</mi></msub></math> decays at Belle and Belle II