We assess the impact of measuring deeply virtual Compton scattering (DVCS) off protons using the planned detector at the Electron-Ion Collider in China (EicC), which is proposed as an upgrade to the High Intensity Heavy-Ion Accelerator Facility (HIAF). We develop a neural-network architecture to flexibly parameterize Compton form factors (CFFs), reliably extrapolate into unmeasured kinematic regions, and provide robust uncertainty estimates using the replica method. The framework is fitted to available worldwide DVCS data using the $ {\mathrm{Gepard}}$ software. We find a significant reduction in the uncertainties of all CFFs after incorporating pseudo-data from single and double polarization asymmetries at the EicC, with particularly strong improvements in the sea-quark region.

China

Yuan-Yuan Huang

Xu Cao

Taifu Feng

Croatia

Krešimir Kumerički

Yu Lu

Assessing the impact of the Electron-Ion Collider in China on deeply virtual Compton scattering * Supported by the National Key R&D Program of China (2023YFA1606703), the National Natural Science Foundation of China (12547111, 12235008, 12405105) and (PK.1.1.10.0004) co-financed by the European Union and through the European Regional Development Fund - Competitiveness and Cohesion Programme 2021-2027. TF also thanks the Hebei Natural Science Foundation (A2022201017, A2023201041) and Natural Science Foundation of Guangxi Autonomous Region (2022GXNSFDA035068)

The interference between amplitudes corresponding to different intermediate resonances plays an important role in generating large CP asymmetries in the phase space in multi-body decays of bottom and charmed mesons. In this study, we examine the CP violation in the decay channel $ {\overline{B}}^{0}\rightarrow K^{-}\pi^{+}\pi^{0} $ in the phase-space region where the intermediate resonances $ \overline{K}^{*}(892)^{0} $ and $ {\overline{K}^{*}_{0}(700)} $ dominate. In particular, the forward-backward asymmetry (FBA) and the CP asymmetry induced by FBA (FB-CPA), which are closely related to the interference effects between the two aforementioned resonances, are investigated. The nontrivial correlation between FBA and FB-CPA is analyzed. The analysis indicates that FB-CPAs around the resonance $ \overline{K}^{*}(892)^{0} $ can be as large as approximately 35%, which can be potentially accessible by Belle and Belle-II collaborations in the near future.

Jian-Yu Yang

Yu-Jie Zhao

Jing-Juan Qi

Zhen-Hua Zhang

The forward-backward asymmetry induced CP asymmetry in ${{\overline{B}}^{0}\rightarrow K^{-}\pi^{+}\pi^{0}}$ in phase space around the resonances ${{\overline{K}}^{*}(892)^{0}}$ and ${{\overline{K}}^{*}_{0}(700)}$ * Supported by National Natural Science Foundation of China (12475096, 12405115, 12192261) and Scientific Research Fund of Hunan Provincial Education Department (22A0319)

We present the first lattice QCD determination of the electromagnetic form factors of the exotic tetraquark <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>b</mi><mi>b</mi></mrow></msub><mo stretchy="false">(</mo><mi>b</mi><mi>b</mi><mover accent="true"><mrow><mi>u</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mover accent="true"><mrow><mi>d</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mo stretchy="false">)</mo></mrow></math> with quantum numbers <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>I</mi><mo stretchy="false">(</mo><msup><mrow><mi>J</mi></mrow><mrow><mi>P</mi></mrow></msup><mo stretchy="false">)</mo><mo>=</mo><mn>0</mn><mo stretchy="false">(</mo><msup><mrow><mn>1</mn></mrow><mrow><mo>+</mo></mrow></msup><mo stretchy="false">)</mo></mrow></math>. The extracted form factors encode information about its internal structure, including the charge distribution and the magnetic dipole moments, determined separately for the light and heavy quarks. Our results provide evidence in favor of it being a bound state consisting of a compact heavy diquark <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">[</mo><mi>b</mi><mi>b</mi><mo stretchy="false">]</mo></math> in a color-antitriplet with spin one and a light antidiquark <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mo stretchy="false">[</mo><mover accent="true"><mrow><mi>u</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mover accent="true"><mrow><mi>d</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mo stretchy="false">]</mo></mrow></math> in a color-triplet with spin zero. The charge radius of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>b</mi><mi>b</mi></mrow></msub></math> is found to be significantly smaller than the combined charge radii of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>*</mo></msup></math> mesons. These two comprise the lowest-lying threshold <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><msup><mi>B</mi><mo>*</mo></msup></math> in the channel that we are considering, and their electric charge form factors are also determined. The computations were performed on a single ensemble, generated by the Coordinated Lattice Simulations effort, with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>N</mi></mrow><mrow><mi>f</mi></mrow></msub><mo>=</mo><mn>2</mn><mo>+</mo><mn>1</mn></mrow></math> dynamical quarks and a lattice spacing of approximately <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>a</mi><mo>≈</mo><mn>0.064</mn><mtext> </mtext><mtext> </mtext><mi>fm</mi></mrow></math> at the pion mass <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>m</mi></mrow><mrow><mi>π</mi></mrow></msub><mo>≈</mo><mn>290</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi></mrow></math>.

Ivan Vujmilovic

Sara Collins

Luka Leskovec

Sasa Prelovsek

Electromagnetic Form Factors and Structure of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>b</mi><mi>b</mi></mrow></msub></mrow></math> Tetraquark from Lattice QCD

The normalised decay rate of $\textit{B}$ → $\textit{J/ψ}$(→ $\textit{μ}$ $\textit{μ}$ )$\textit{K}$ is measured as a function of the lepton helicity angle using a data sample corresponding to an integrated luminosity of 1$\textit{.}$1 fb collected during October 2024 with the upgraded (Upgrade I) LHCb detector. This angular distribution can be parameterised by two coefficients, the forward-backward asymmetry, $\textit{A}$ , and the flatness parameter, $\textit{F}$ , whose values are constrained by conservation of angular momentum. These coefficients are measured both integrated and differentially across various kinematic and detector-response variables, and the results are found to be in good agreement with expectations. These measurements show that the detector response of the LHCb Upgrade I experiment is understood to the precision required to reliably extract the angular coefficients associated with rare $\textit{b}$ → $\textit{sμ}$ $\textit{μ}$ and $\textit{b}$ → $\textit{dμ}$ $\textit{μ}$ transitions, which are particularly sensitive to physics beyond the Standard Model.

Netherlands

R. Aaij

United Kingdom

A. Abdelmotteleb

Switzerland

C. Abellan Beteta

F. Abudinén

T. Ackernley

United States

A. Adefisoye

Spain

B. Adeva

M. Adinolfi

Sweden

P. Adlarson

France

C. Agapopoulou

C. Aidala

Z. Ajaltouni

S. Akar

K. Akiba

Poland

M. Akthar

Italy

P. Albicocco

Germany

J. Albrecht

Lithuania

R. Aleksiejunas

F. Alessio

P. Alvarez Cartelle

R. Amalric

Brazil

S. Amato

J. Amey

Y. Amhis

L. An

L. Anderlini

M. Andersson

P. Andreola

M. Andreotti

S. Andres Estrada

A. Anelli

D. Ao

C. Arata

F. Archilli

Z. Areg

M. Argenton

Costa Rica

S. Arguedas Cuendis

L. Arnone

Russia

A. Artamonov

M. Artuso

E. Aslanides

R. Ataíde Da Silva

M. Atzeni

B. Audurier

J. Authier

D. Bacher

I. Bachiller Perea

S. Bachmann

M. Bachmayer

J. Back

P. Baladron Rodriguez

V. Balagura

A. Balboni

W. Baldini

Z. Baldwin

L. Balzani

H. Bao

J. Baptista de Souza Leite

C. Barbero Pretel

M. Barbetti

I. Barbosa

R. Barlow

M. Barnyakov

S. Barsuk

W. Barter

J. Bartz

S. Bashir

B. Batsukh

P. Battista

A. Bay

A. Beck

M. Becker

F. Bedeschi

I. Bediaga

N. Behling

S. Belin

A. Bellavista

K. Belous

I. Belov

I. Belyaev

E. Ben-Haim

G. Benane

G. Bencivenni

A. Berezhnoy

R. Bernet

S. Bernet Andres

A. Bertolin

F. Betti

J. Bex

Ukraine

O. Bezshyyko

Hungary

S. Bhattacharya

J. Bhom

M. Bieker

N. Biesuz

A. Biolchini

M. Birch

F. Bishop

A. Bitadze

A. Bizzeti

T. Blake

Differential decay rate of $\textit{B}$ + $\textit{→ J/ψK}$ + with the LHCb Upgrade I experiment

Recent lattice QCD simulations and phenomenological models indicate that the nucleon’s gravitational form factor <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>N</mi></msub><mo stretchy="false">(</mo><mi>t</mi><mo stretchy="false">)</mo></math> remains remarkably small at finite momentum transfer <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>t</mi></math>. While <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>N</mi></msub><mo stretchy="false">(</mo><mn>0</mn><mo stretchy="false">)</mo><mo>=</mo><mn>0</mn></math> is a known consequence of the equivalence principle, the physical origin of its suppression at finite <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>t</mi></math> has not been fully elucidated. In this work, we demonstrate that the smallness of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>N</mi></msub><mo stretchy="false">(</mo><mi>t</mi><mo stretchy="false">)</mo></math> arises from a fundamental cancellation within the nucleon’s wave functions. Using light-front holographic QCD, we show that <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>N</mi></msub><mo stretchy="false">(</mo><mi>t</mi><mo stretchy="false">)</mo></math> is governed by an antisymmetric factor in the longitudinal dynamics that leads to an exact vanishing in the symmetric limit and significant suppression for realistic nucleon structures. Our results suggest that the smallness of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>N</mi></msub><mo stretchy="false">(</mo><mi>t</mi><mo stretchy="false">)</mo></math> is a signature of the nucleon’s dominant S-wave character, providing a formal justification for its frequent omission in practical applications like near-threshold <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math> production.

Xianghui Cao

Bheemsehan Gurjar

Chandan Mondal

Chen Chen

Yang Li

Origin of the nucleon gravitational form factor <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>N</mi></msub><mo stretchy="false">(</mo><mi>t</mi><mo stretchy="false">)</mo></math>: Exposition in light-front holographic QCD

The decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>B</mi></mrow><mrow><mo>±</mo></mrow></msup><mo stretchy="false">→</mo><msubsup><mrow><mi>K</mi></mrow><mrow><mi mathvariant="normal">S</mi></mrow><mrow><mn>0</mn></mrow></msubsup><msup><mrow><mi>π</mi></mrow><mrow><mo>±</mo></mrow></msup></mrow></math>, with a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> asymmetry expected to be close to zero in the standard model, is theoretically clean and sensitive to potential new physics. An analysis of the decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>B</mi></mrow><mrow><mo>±</mo></mrow></msup><mo stretchy="false">→</mo><msubsup><mrow><mi>K</mi></mrow><mrow><mi mathvariant="normal">S</mi></mrow><mrow><mn>0</mn></mrow></msubsup><msup><mrow><mi>π</mi></mrow><mrow><mo>±</mo></mrow></msup></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>±</mo></msup><mo stretchy="false">→</mo><msubsup><mi>K</mi><mi mathvariant="normal">S</mi><mn>0</mn></msubsup><msup><mi>K</mi><mo>±</mo></msup></math> is performed using proton-proton collision data collected by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>5.4</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>. The <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> asymmetries are determined to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi mathvariant="script">A</mi></mrow><mrow><mi>C</mi><mi>P</mi></mrow></msup><mo stretchy="false">(</mo><msup><mrow><mi>B</mi></mrow><mrow><mo>±</mo></mrow></msup><mo stretchy="false">→</mo><msubsup><mrow><mi>K</mi></mrow><mrow><mi mathvariant="normal">S</mi></mrow><mrow><mn>0</mn></mrow></msubsup><msup><mrow><mi>π</mi></mrow><mrow><mo>±</mo></mrow></msup><mo stretchy="false">)</mo><mo>=</mo><mo>−</mo><mn>0.028</mn><mo>±</mo><mn>0.009</mn><mo>±</mo><mn>0.009</mn></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi mathvariant="script">A</mi></mrow><mrow><mi>C</mi><mi>P</mi></mrow></msup><mo stretchy="false">(</mo><msup><mrow><mi>B</mi></mrow><mrow><mo>±</mo></mrow></msup><mo stretchy="false">→</mo><msubsup><mrow><mi>K</mi></mrow><mrow><mi mathvariant="normal">S</mi></mrow><mrow><mn>0</mn></mrow></msubsup><msup><mrow><mi>K</mi></mrow><mrow><mo>±</mo></mrow></msup><mo stretchy="false">)</mo><mo>=</mo><mn>0.118</mn><mo>±</mo><mn>0.062</mn><mo>±</mo><mn>0.031</mn></mrow></math>, and the branching fraction ratio is measured to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msup><mrow><mi>B</mi></mrow><mrow><mo>±</mo></mrow></msup><mo stretchy="false">→</mo><msubsup><mrow><mi>K</mi></mrow><mrow><mi mathvariant="normal">S</mi></mrow><mrow><mn>0</mn></mrow></msubsup><msup><mrow><mi>K</mi></mrow><mrow><mo>±</mo></mrow></msup><mo stretchy="false">)</mo><mo>/</mo><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msup><mrow><mi>B</mi></mrow><mrow><mo>±</mo></mrow></msup><mo stretchy="false">→</mo><msubsup><mrow><mi>K</mi></mrow><mrow><mi mathvariant="normal">S</mi></mrow><mrow><mn>0</mn></mrow></msubsup><msup><mrow><mi>π</mi></mrow><mrow><mo>±</mo></mrow></msup><mo stretchy="false">)</mo><mo>=</mo><mn>0.055</mn><mo>±</mo><mn>0.004</mn><mo>±</mo><mn>0.002</mn></mrow></math>, where the first uncertainties are statistical and the second are systematic. These results are the most precise measurements of these quantities to date. A search for the rare decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>c</mi><mo>±</mo></msubsup><mo stretchy="false">→</mo><msubsup><mi>K</mi><mi mathvariant="normal">S</mi><mn>0</mn></msubsup><msup><mi>K</mi><mo>±</mo></msup></math> is also performed. No significant signal is observed, and the upper limit on the product of the branching fraction ratio <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msubsup><mrow><mi>B</mi></mrow><mrow><mi>c</mi></mrow><mrow><mo>±</mo></mrow></msubsup><mo stretchy="false">→</mo><msubsup><mrow><mi>K</mi></mrow><mrow><mi mathvariant="normal">S</mi></mrow><mrow><mn>0</mn></mrow></msubsup><msup><mrow><mi>K</mi></mrow><mrow><mo>±</mo></mrow></msup><mo stretchy="false">)</mo><mo>/</mo><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msup><mrow><mi>B</mi></mrow><mrow><mo>±</mo></mrow></msup><mo stretchy="false">→</mo><msubsup><mrow><mi>K</mi></mrow><mrow><mi mathvariant="normal">S</mi></mrow><mrow><mn>0</mn></mrow></msubsup><msup><mrow><mi>π</mi></mrow><mrow><mo>±</mo></mrow></msup><mo stretchy="false">)</mo></mrow></math> and the fragmentation-fraction ratio <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>f</mi><mi>c</mi></msub><mo>/</mo><msub><mi>f</mi><mi>u</mi></msub></math> is set to be 0.015 (0.016) at the 90% (95%) confidence level.

A.S.W. Abdelmotteleb

A.A. Adefisoye

C.A. Aidala

J.L. Amey

J.A. Authier

J.J. Back

I.R. Barbosa

R.J. Barlow

P.B. Battista

I.B. Bediaga

N.A. Behling

M.S. Bieker

N.V. Biesuz

F.C.R. Bishop

F. Blanc

Precision Measurement of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> Violation and Branching Fractions in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>B</mi></mrow><mrow><mo>±</mo></mrow></msup><mo stretchy="false">→</mo><msubsup><mrow><mi>K</mi></mrow><mrow><mi>S</mi></mrow><mrow><mn>0</mn></mrow></msubsup><msup><mrow><mi>h</mi></mrow><mrow><mo>±</mo></mrow></msup></mrow></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>h</mi><mo>=</mo><mi>π</mi></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>K</mi></mrow></math>) Decays and Search for the Rare Decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi>B</mi></mrow><mrow><mi>c</mi></mrow><mrow><mo>±</mo></mrow></msubsup><mo stretchy="false">→</mo><msubsup><mrow><mi>K</mi></mrow><mrow><mi>S</mi></mrow><mrow><mn>0</mn></mrow></msubsup><msup><mrow><mi>K</mi></mrow><mrow><mo>±</mo></mrow></msup></mrow></math>

In double charmonium production, a long-standing challenge is that the theoretical predictions are not consistent with the measurements at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math> factories. Within the Non-Relativistic Quantum Chromodynamics (NRQCD) framework, the next-to-leading order calculation has proved its power to cut down the discrepancy between theory and experiments. To further clarify this puzzle, we have performed the next-to-next-to-leading order calculation. The amplitude is obtained as an analytical asymptotic expansion in the ratio of the squared charm-quark mass over the squared center-of-mass energy, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>m</mi><mi>c</mi><mn>2</mn></msubsup><mo>/</mo><mi>s</mi></math>. We investigate the origin of the leading logarithms by performing a region analysis, revealing the intricate factorization structure in this process. We provide numerical predictions on the total cross sections of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mo>+</mo><msub><mi>η</mi><mi>c</mi></msub></math> production, which agree with the experimental results. Extension of our computation to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">ϒ</mi><mo>+</mo><msub><mi>η</mi><mi>b</mi></msub></math> production is also discussed.

Xiang Chen

Xin Guan

Chuan-Qi He

Yan-Qing Ma

Jian Wang

Da-Jiang Zhang

Analytical two-loop amplitudes 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><mo stretchy="false">→</mo><mi>J</mi><mo>/</mo><mi>ψ</mi><mo>+</mo><msub><mi>η</mi><mi>c</mi></msub></math> at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math> factories

In 2023, the Belle II Collaboration announced the observation of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>B</mi></mrow><mrow><mo>+</mo></mrow></msup><mo stretchy="false">→</mo><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup><mi>ν</mi><mover accent="true"><mrow><mi>ν</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover></mrow></math> decay channel for the first time. This decay channel provides a clean signal with high precision in theoretical calculations. However, we encounter a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2.8</mn><mi>σ</mi></math> deviation from the Standard Model prediction. To resolve this excess, we study a scalar dark matter model with local discrete <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mn>3</mn></msub></math> symmetry. Assuming dark <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi><mo stretchy="false">(</mo><mn>1</mn><msub><mo stretchy="false">)</mo><mi>X</mi></msub><mo>≡</mo><mi>U</mi><mo stretchy="false">(</mo><mn>1</mn><msub><mo stretchy="false">)</mo><mrow><msub><mi>L</mi><mi>μ</mi></msub><mo>−</mo><msub><mi>L</mi><mi>τ</mi></msub></mrow></msub></math> symmetry, this <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi><mo stretchy="false">(</mo><mn>1</mn><msub><mo stretchy="false">)</mo><mrow><msub><mi>L</mi><mi>μ</mi></msub><mo>−</mo><msub><mi>L</mi><mi>τ</mi></msub></mrow></msub></math> symmetry is spontaneously broken into local discrete <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mn>3</mn></msub></math> by nonzero vacuum expectation value of dark Higgs boson. Considering a dark Higgs mass is 2 GeV, we can explain the recent <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>Br</mi><mo stretchy="false">(</mo><msup><mrow><mi>B</mi></mrow><mrow><mo>+</mo></mrow></msup><mo stretchy="false">→</mo><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup><mi>ν</mi><mover accent="true"><mrow><mi>ν</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mo stretchy="false">)</mo></mrow></math> excess reported from the Belle II Collaboration and relic abundance at the same time.

Jongkuk Kim

Pyungwon Ko

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mrow><msup><mrow><mi>B</mi></mrow><mrow><mo>+</mo></mrow></msup><mo stretchy="false">→</mo></mrow><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup><mi>ν</mi><mover accent="true"><mrow><mi>ν</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover></mrow></math> excess and DM semi-annihilation

We propose the Λ <inf><italic>b</italic></inf>&#8239;&#8594;&#8239; <italic>&#981;&#951;<inf>c</inf></italic>&#923; reaction to observe a <italic>P<inf>cs</inf></italic> state around 4200 MeV, predicted at lower masses than expected from comparison with the <italic>P<inf>c</inf></italic> states, stemming as a consequence of the important role played by coupled channels in the <italic>P<inf>cs</inf></italic> case, which does not appear in the <italic>P<inf>c</inf></italic> case. That state decays to <italic>&#951;<inf>c</inf></italic>&#923; with a width of about 200 keV. The reaction is related to <math altimg='si78.svg'><mrow><msubsup><mstyle mathvariant='normal'><mi>&#923;</mi></mstyle><mi>b</mi><mn>0</mn></msubsup><mo>&#8594;</mo><mi>&#981;</mi><msubsup><mi>D</mi><mi>s</mi><mo>&#8722;</mo></msubsup><msubsup><mstyle mathvariant='normal'><mi>&#923;</mi></mstyle><mi>c</mi><mo>+</mo></msubsup></mrow></math>, which has already been observed. We predict a branching fraction for &#923; <inf><italic>b</italic></inf>&#8239;&#8594;&#8239; <italic>&#981;P<inf>cs</inf></italic>(4200); <italic>P<inf>cs</inf></italic>&#8239;&#8594;&#8239; <italic>&#951;<inf>c</inf></italic>&#923; of the order of <math altimg='si79.svg'><msup><mn>10</mn><mrow><mo>&#8722;</mo><mn>5</mn></mrow></msup></math>, which is within present capabilities of the LHCb collaboration. The observation of this state would bring valuable light on the nature of the <italic>P<inf>c</inf></italic> and <italic>P<inf>cs</inf></italic> states and the role played by coupled channels in hadron structure and hadron reactions.

Wen-Tao Lyu

Eulogio Oset

Searching for a <italic>P<inf>cs</inf></italic>(4200) state in the &#923; <inf><italic>b</italic></inf>&#8239;&#8594;&#8239; <italic>&#981;&#951;<inf>c</inf></italic>&#923; reaction

We investigate the decays $$ {B}_c^{-} $$ → $$ {\overline{D}}^{\left(\ast \right)0}{\ell}^{-}{\overline{\nu}}_{\ell } $$ and $$ {B}_c^{-} $$ → $\textit{D}$ $\textit{ℓ}$ $\textit{ℓ}$ within the Standard Model (SM), employing perturbative QCD (pQCD) form factors that are sensitive to the wave functions of $\textit{B}$ and $\textit{D}$ mesons. Using lattice QCD inputs for $\textit{B}$ → $\textit{D}$ and $\textit{B}$ → $\textit{D}$ transitions, we extract the shape parameters of the meson wave functions and estimate the $\textit{q}$ -dependence of $\textit{B}$ → $\textit{D}$ form factors via heavy quark spin symmetry. We present predictions for branching fractions, lepton flavor violating observables, and perform a detailed angular analysis of the cascade decay $$ {B}_c^{-} $$ → $\textit{D}$ (→ $\textit{D}$ $\textit{π}$ )$\textit{ℓ}$ $\textit{ℓ}$ , providing SM expectations for several angular observables.

India

Utsab Dey

Soumitra Nandi

Study of form factors and observables in $$ {B}_c^{-} $$ → $$ {\overline{D}}^{\left(\ast \right)0}{\ell}^{-}{\overline{\nu}}_{\ell } $$ and $$ {B}_c^{-} $$ → $\textit{D}$ (∗)− $\textit{ℓ}$ + $\textit{ℓ}$ − decays